UNITED STATES DEPARTMENT OF THE INTERIOR

OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT

Colowyo Coal Mine 

South Taylor/Lower Wilson Permit Expansion Area Project 

Federal Mining Plan Modification 

Environmental Assessment

Moffat and Rio Blanco Counties, Colorado

August 2015

Prepared in cooperation with the 

Bureau of Land Management, 

State of Colorado’s Department of Natural Resources, 

and Moffat County

U.S. Department of the Interior

Office of Surface Mining Reclamation and Enforcement

Program Support Division

1999 Broadway, Suite 3320

Denver, CO 80202

PH: 303-293-5000

FAX: 303-293-5032
Table of Contents and Acronyms

Table of Contents and Acronyms

Table of Contents

CHAPTER 1 PURPOSE AND NEED

1.1 Introduction ..................................................................................................................................1-1

1.2 Background....................................................................................................................................1-2

1.2.1 Statutory and Regulatory Background............................................................................1-5

1.3 Purpose and Need .......................................................................................................................1-5

1.3.1 Need.......................................................................................................................................1-5

1.3.2 Purpose ..................................................................................................................................1-6

1.4 Relationship to Statutes, Regulations, and Other Agency Plans........................................1-6

1.4.1 Statutes and Regulations....................................................................................................1-6

1.4.2 Other Agency Plans.............................................................................................................1-7

1.5 Authorizing Actions.....................................................................................................................1-8

1.6 Outreach and Issues....................................................................................................................1-8

CHAPTER 2 PROPOSED ACTION AND ALTERNATIVES

2.1 Introduction ..................................................................................................................................2-1

2.2 Alternative A – Proposed Action – PR02 as Approved in 2007.......................................2-4

2.2.1 Proposed Mine Operation Components in 2007.........................................................2-5

2.2.2 Methods and Operation.....................................................................................................2-8

2.2.3 Project Design Features.....................................................................................................2-9

2.3 Alternative B – PR02 as Revised.............................................................................................2-12

2.3.1 CDRMS Approved Revisions to the Permit 2008 - Present....................................2-13

2.3.2 Currently Approved Mine Operation Components..................................................2-15

2.3.3 Mining Methods and Operation......................................................................................2-16

2.3.4 Project Design Features...................................................................................................2-16

2.4 Alternative C - No Action Alternative .................................................................................2-18

2.5 Alternatives Considered but Eliminated from Further Study ..........................................2-18

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2.5.1 Underground Mining Alternative ...................................................................................2-19

2.5.2 Air Quality Mitigation Alternatives................................................................................2-19

2.5.3 Mining Plan with Reduced Disturbance Alternatives.........................................................2-20

CHAPTER 3 AFFECTED ENVIRONMENT

3.1 GENERAL SETTING...................................................................................................................3-1

3.2 TOPOGRAPHY............................................................................................................................3-3

3.3 AIR AND CLIMATE RESOURCES ..........................................................................................3-3

3.3.1 Airshed for Analysis............................................................................................................3-3

3.3.2 Regional Climate..................................................................................................................3-4

3.3.3 Local Climate and Meteorology .......................................................................................3-4

3.3.4 Regulatory Requirements ..................................................................................................3-7

3.3.5 Regional Air Quality..........................................................................................................3-13

3.3.6 Hazardous Air Pollutants.................................................................................................3-17

3.3.7 Onsite Air Quality.............................................................................................................3-17

3.3.8 Existing Air Pollutant Emission Sources .......................................................................3-19

3.3.9 Existing Coal Combustion Environment ......................................................................3-19

3.3.10 Climate Change..................................................................................................................3-20

3.3.11 Black Carbon ......................................................................................................................3-23

3.4 GEOLOGY..................................................................................................................................3-24

3.4.1 Minerals................................................................................................................................3-24

3.5 WATER RESOURCES ..............................................................................................................3-25

3.5.1 Surface Water....................................................................................................................3-25

3.5.2 Groundwater......................................................................................................................3-30

3.6 VEGETATION............................................................................................................................3-33

3.6.1 Mountain Shrub Community...........................................................................................3-33

3.6.2 Sagebrush Community......................................................................................................3-34

3.6.3 Aspen Woodland Community........................................................................................3-34

3.6.4 Juniper Shrub Community ...............................................................................................3-34

3.6.5 Bottomland Community...................................................................................................3-36

3.6.6 Grassland Community ......................................................................................................3-36

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3.6.7 Riparian ................................................................................................................................3-36

3.6.8 Other Communities..........................................................................................................3-37

3.6.9 Noxious Weeds.................................................................................................................3-37

3.7 WETLANDS AND RIPARIAN ZONES ...............................................................................3-37

3.7.1 Wetlands and Riparian Zones.........................................................................................3-37

3.7.2 Waters of the U.S..............................................................................................................3-38

3.8 FISH AND WILDLIFE RESOURCES .....................................................................................3-39

3.8.1 Mammals..............................................................................................................................3-39

3.8.2 Big Game..............................................................................................................................3-40

3.8.3 Migratory Birds...................................................................................................................3-44

3.8.4 Raptors.................................................................................................................................3-45

3.8.5 Reptiles and Amphibians..................................................................................................3-46

3.8.6 Fish ........................................................................................................................................3-46

3.9 SPECIAL STATUS SPECIES .....................................................................................................3-46

3.9.1 Threatened, Endangered, and Candidate Species ............................................................3-48

3.9.2 State Listed and BLM Sensitive Species ........................................................................3-55

3.10 CULTURAL AND HISTORIC RESOURCES.......................................................................3-59

3.10.1 Cultural Context ...............................................................................................................3-59

3.10.2 Project Specific Inventory ................................................................................................3-60

3.11 INDIAN CONCERNS ..............................................................................................................3-60

3.12 SOCIOECONOMICS ...............................................................................................................3-61

3.13 ENVIRONMENTAL JUSTICE .................................................................................................3-63

3.14 VISUAL .........................................................................................................................................3-64

3.14.1 BLM Visual Resources Management..............................................................................3-64

3.14.2 Project Area Visual Resources.......................................................................................3-65

3.15 RECREATION............................................................................................................................3-66

3.16 PALEONTOLOGY....................................................................................................................3-66

3.17 ACCESS AND TRANSPORTATION ...................................................................................3-67

3.18 SOLID OR HAZARDOUS WASTE ......................................................................................3-67

3.19 NOISE...........................................................................................................................................3-68

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3.20 LIVESTOCK GRAZING...........................................................................................................3-70

3.21 SOILS ............................................................................................................................................3-71

3.22 PRIME FARMLANDS.................................................................................................................3-78

3.23 ALLUVIAL VALLEY FLOORS .................................................................................................3-78

CHAPTER 4 ENVIRONMENTAL CONSEQUENCES (DIRECT AND INDIRECT IMPACTS)

4.1 Introduction ..................................................................................................................................4-1

4.1.1 Summary Comparison of Direct and Indirect Environmental Impacts....................4-3

4.2 Topography ...................................................................................................................................4-7

4.2.1 Alternative A – Proposed Action, PR02 as Approved in 2007 .................................4-7

4.2.2 Alternative B – PR02 as Revised ......................................................................................4-7

4.2.3 No Action Alternative........................................................................................................4-8

4.2.4 Mitigation Measures............................................................................................................4-8

4.3 Air and Climate Resources........................................................................................................4-8

4.3.1 Alternative A - Proposed Action, PR02 as Approved in 2007..................................4-8

4.3.2 Alternative B – PR02 as Revised ....................................................................................4-25

4.3.3 No Action Alternative......................................................................................................4-55

4.3.4 Mitigation Measures..........................................................................................................4-57

4.4 Geology ........................................................................................................................................4-58

4.4.1 Alternative A – Proposed Action, PR02 as Approved in 2007 ...............................4-58

4.4.2 Alternative B – PR02 as Revised ....................................................................................4-58

4.4.3 No Action Alternative......................................................................................................4-59

4.4.4 Mitigation Measures..........................................................................................................4-59

4.5 Water Resources.......................................................................................................................4-59

4.5.1 Alternative A – Proposed Action, PR02 as Approved in 2007 ...............................4-59

4.5.2 Alternative B – PR02 as Revised ....................................................................................4-64

4.5.3 No Action Alternative......................................................................................................4-68

4.5.4 Mitigation Measures..........................................................................................................4-68

4.6 Vegetation....................................................................................................................................4-68

4.6.1 Alternative A – Proposed Action, PR02 as Approved in 2007 ...............................4-68

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4.6.2 Alternative B – PR02 as Revised ....................................................................................4-69

4.6.3 No Action Alternative......................................................................................................4-70

4.6.4 Mitigation Measures..........................................................................................................4-70

4.7 Wetlands......................................................................................................................................4-71

4.7.1 Alternative A – Proposed Action, PR02 as Approved in 2007 ...............................4-71

4.7.2 Alternative B – PR02 as Revised ....................................................................................4-71

4.7.3 No Action Alternative......................................................................................................4-71

4.7.4 Mitigation Measures..........................................................................................................4-71

4.8 Fish and Wildlife.........................................................................................................................4-71

4.8.1 Alternative A – Proposed Action, PR02 as Approved in 2007 ...............................4-71

4.8.2 Alternative B – PR02 as Revised ....................................................................................4-73

4.8.3 No Action Alternative......................................................................................................4-74

4.8.4 Mitigation Measures..........................................................................................................4-74

4.9 Special Status Species................................................................................................................4-74

4.9.1 Alternative A – Proposed Action, PR02 as Approved in 2007 ...............................4-74

4.9.2 Alternative B – PR02 as Revised ....................................................................................4-83

4.9.3 No Action Alternative......................................................................................................4-86

4.9.4 Mitigation Measures..........................................................................................................4-87

4.10 Cultural and Historic Resources............................................................................................4-88

4.10.1 Alternative A – Proposed Action, PR02 as Approved in 2007 ...............................4-88

4.10.2 Alternative B – PR02 as Revised ....................................................................................4-89

4.10.3 No Action Alternative......................................................................................................4-89

4.10.4 Mitigation Measures..........................................................................................................4-89

4.11 Indian Concerns.........................................................................................................................4-90

4.11.1 Alternative A – Proposed Action, PR02 as Approved in 2007 ...............................4-90

4.11.2 Alternative B – PR02 as Revised ....................................................................................4-91

4.11.3 No Action Alternative......................................................................................................4-91

4.11.4 Mitigation Measures..........................................................................................................4-91

4.12 Socioeconomics..........................................................................................................................4-91

4.12.1 Alternative A – Proposed Action, PR02 as Approved in 2007 ...............................4-91

4.12.2 Alternative B – PR02 as Revised ....................................................................................4-92

4.12.3 No Action Alternative......................................................................................................4-93

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4.12.4 Mitigation Measures..........................................................................................................4-93

4.13 Visual Resources ........................................................................................................................4-93

4.13.1 Alternative A – Proposed Action, PR02 as Approved in 2007 ...............................4-93

4.13.2 Alternative B – PR02 as Revised ....................................................................................4-95

4.13.3 No Action Alternative......................................................................................................4-96

4.13.4 Mitigation Measures..........................................................................................................4-96

4.14 Recreation ...................................................................................................................................4-97

4.14.1 Alternative A – Proposed Action, PR02 as Approved in 2007 ...............................4-97

4.14.2 Alternative B – PR02 as Revised ....................................................................................4-97

4.14.3 No Action Alternative......................................................................................................4-97

4.14.4 Mitigation Measures..........................................................................................................4-97

4.15 Paleontology................................................................................................................................4-98

4.15.1 Alternative A – Proposed Action, PR02 as Approved in 2007 ...............................4-98

4.15.2 Alternative B – PR02 as Revised ....................................................................................4-98

4.15.3 No Action Alternative......................................................................................................4-98

4.15.4 Mitigation Measures..........................................................................................................4-98

4.16 Access and Transportation......................................................................................................4-99

4.16.1 Alternative A – Proposed Action, PR02 as Approved in 2007 ...............................4-99

4.16.2 Alternative B – PR02 as Revised ....................................................................................4-99

4.16.3 No Action Alternative................................................................................................... 4-100

4.16.4 Mitigation Measures....................................................................................................... 4-100

4.17 Solid or Hazardous Waste.................................................................................................... 4-100

4.17.1 Alternative A – Proposed Action, PR02 as Approved in 2007 ............................ 4-100

4.17.2 Alternative B – PR02 as Revised ................................................................................. 4-101

4.17.3 No Action Alternative................................................................................................... 4-101

4.17.4 Mitigation Measures....................................................................................................... 4-101

4.18 Noise.......................................................................................................................................... 4-101

4.18.1 Alternative A – Proposed Action, PR02 as Approved in 2007 ............................ 4-101

4.18.2 Alternative B – PR02 as Revised ................................................................................. 4-101

4.18.3 No Action Alternative................................................................................................... 4-102

4.18.4 Mitigation Measures....................................................................................................... 4-102

4.19 Livestock Grazing.................................................................................................................... 4-102

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4.19.1 Alternative A – Proposed Action, PR02 as Approved in 2007 ............................ 4-102

4.19.2 Alternative B – PR02 as Revised ................................................................................. 4-103

4.19.3 No Action Alternative................................................................................................... 4-103

4.19.4 Mitigation Measures....................................................................................................... 4-103

4.20 Soils............................................................................................................................................ 4-104

4.20.1 Alternative A – Proposed Action, PR02 as Approved in 2007 ............................ 4-104

4.20.2 Alternative B – PR02 as Revised ................................................................................. 4-105

4.20.3 No Action Alternative................................................................................................... 4-106

4.20.4 Mitigation Measures....................................................................................................... 4-107

4.21 Alluvial Valley Floors.............................................................................................................. 4-107

4.21.1 Alternative A – Proposed Action, PR02 as Approved in 2007 ............................ 4-107

4.21.2 Alternative B – PR02 as Revised ................................................................................. 4-107

4.21.3 No Action Alternative................................................................................................... 4-108

4.21.4 Mitigation Measures....................................................................................................... 4-108

CHAPTER 5 CUMULATIVE IMPACTS

5.1 Introduction ..................................................................................................................................5-1

5.2 Past and Present Actions............................................................................................................5-1

5.3 Reasonably Foreseeable Future Actions.................................................................................5-3

5.4 Cumulative Impacts.....................................................................................................................5-5

5.4.1 Topography...........................................................................................................................5-5

5.4.2 Air and Climate Resources................................................................................................5-5

5.4.3 Geology................................................................................................................................5-21

5.4.4 Water Resources...............................................................................................................5-21

5.4.5 Vegetation ...........................................................................................................................5-22

5.4.6 Wetlands..............................................................................................................................5-22

5.4.7 Fish and Wildlife.................................................................................................................5-23

5.4.8 Special Status Species........................................................................................................5-24

5.4.9 Cultural and Historic Resources....................................................................................5-25

5.4.10 Indian Concerns.................................................................................................................5-26

5.4.11 Socioeconomics .................................................................................................................5-26

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5.4.12 Visual Resources................................................................................................................5-27

5.4.13 Recreation ...........................................................................................................................5-27

5.4.14 Paleontology........................................................................................................................5-28

5.4.15 Access and Transportation..............................................................................................5-28

5.4.16 Solid and Hazardous Waste ............................................................................................5-28

5.4.17 Noise ....................................................................................................................................5-29

5.4.18 Livestock..............................................................................................................................5-29

5.4.19 Soils.......................................................................................................................................5-29

5.4.20 Alluvial Valley Floors.........................................................................................................5-30

CHAPTER 6 COORDINATION AND CONSULTATION

6.1 Agencies/Persons Consulted .....................................................................................................6-1

6.1.1 Public Comment Process........................................................................................................6-1

6.1.2 US Fish and Wildlife Section 7 Process................................................................................6-2

6.1.3 Tribal Consultation .................................................................................................................6-2

6.2 Cooperating Agencies.................................................................................................................6-3

6.3 Preparers and Participants.........................................................................................................6-4

CHAPTER 7 REFERENCES

7.1 References.....................................................................................................................................7-1

Appendix A Legal Notice and Outreach Letter

Appendix B Design Features and Resource Protection Plans

Appendix C Air Data Tables

Appendix D 2006, 2007, and 2015 Biological Opinions

Appendix E SHPO Consultation and Tribal Consultation

Appendix F Public Comments on the Draft EA and OSMRE Response

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List of Tables

Table 1.6-1 Public Outreach Comments Categorized by Resource Topic .................................1-9

Table 2.2-1 Alternative A Proposed Disturbance Acreage by Project Component .................2-7

Table 2.2-2 Summary of Principal Design Features.........................................................................2-10

Table 2.3-1 Alternative B Proposed Acreage by Project Component........................................2-16

Table 2.3-2 Summary of Alternative B Additional Design Features............................................2-18

Table 3.1-1 Resources and Determination of Need for Further Analysis.................................................1

Table 3.3-1 National Ambient Air Quality Standards ...........................................................................8

Table 3.3-2 Federal Prevention of Significant Deterioration Limits...................................................9

Table 3.3-3 MATS Emission Requirements........................................................................................... 12

Table 3.3-4 Regional Air Quality Monitoring Conditions.................................................................. 15

Table 3.3-5 Colowyo Mine Network High PM10 Concentration Events........................................ 18

Table 3.3-6 Regional Coal Fired Generating 2014 CDPHE Reported Actual Emissions........... 19

Table 3.3-7 U.S. Greenhouse Gas Emissions Allocated to Economic Sectors............................. 21

Table 3.3-8 U.S. Greenhouse Gas Emissions and Sinks..................................................................... 21

Table 3.3-9 U.S. Sulfur Dioxide (Indirect GHG) Emissions .............................................................. 22

Table 3.6-1 Vegetation Communities within the Project Area........................................................ 33

Table 3.8-1 BCC Species that have the Potential to Occur in the Project Area......................... 44

Table 3.9-1 Federal, State, and BLM Sensitive Species in Moffat and Rio Blanco Counties....... 46

Table 3.9-2 GSG Lek Counts Near the Project Area ........................................................................ 52

Table 3.9-3 Columbian Sharp-tailed Grouse Lek Counts in the Vicinity of the Project Area.. 57

Table 3.12-1 Population Estimates........................................................................................................... 61

Table 3.12-2 Per Capita Personal Income .............................................................................................. 61

Table 3.12-3 Mean Household Income ................................................................................................... 61

Table 3.12-4 Housing Characteristics...................................................................................................... 62

Table 3.19-1 Sound Levels Associated With Ordinary Noise Sources........................................... 69

Table 3.20-1 Grazing Allotments.............................................................................................................. 70

Table 4.3-1 Criteria Pollutant and HAP Emission Estimates (tpy), Alternative A....................4-10

Table 4.3-2 Direct GHG Emissions (metric tpy), Alternative A..................................................4-13

Table 4.3-3 Black Carbon Emissions (tpy) from Haul Trucks, Alternative A............................4-13

Table 4.3-4 Reporting Year 2014 Criteria Emissions Data ...........................................................4-16

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Table 4.3-5 Predicted Criteria Emissions Data Based on Regional Maximum, Average, and 

Craig Generating Station Only Emissions Rates........................................................4-16

Table 4.3-6 Predicted Criteria Emissions Data Based on Regional Maximum, Average, and 

Craig Generating Station Only Emissions Rates........................................................4-17

Table 4.3-7 GHG Coal Combustion Emissions, Alternative A.....................................................4-18

Table 4.3-8 Predicted Ozone Precursor Emissions Rates Based on 2013 Craig Generating 

Station Factors and Blasting Emissions, Alternative A................................................4-21

Table 4.3-9 2014 Western Slope Ozone Monitor Concentrations............................................4-22

Table 4.3-10 TRI Reported Atmospheric Emissions for the Craig Generating Station ............4-23

Table 4.3-11 Potential Coal Comb. Merc. Emissions, Craig Gen. Sta. TRI Actual Emissions..4-23

Table 4.3-12 Railroad Coal Transportation, Railroad Maintenance Emission Estimates (tpy) 4-25

Table 4.3-13 APEN Activity Breakdown..............................................................................................4-26

Table 4.3-14 Maximum APEN Particulate Estimates from 2007-2014..........................................4-27

Table 4.3-15 Monitoring Station Potential High Values, Alternative B ..........................................4-28

Table 4.3-16 High Value Dates................................................................................................................4-28

Table 4.3-17 High Wind Days................................................................................................................4-29

Table 4.3-18 Maximum Emission Estimates 2007-2014 (tpy)..........................................................4-31

Table 4.3-19 Annual Methane Emissions 2015-2019, Alternative B ..............................................4-31

Table 4.3-20 Black Carbon Emissions (tpy) from Haul Trucks, Alternative B............................4-32

Table 4.3-21 Alternative B GHG Emissions, 4 mtpy.........................................................................4-33

Table 4.3-22 Alternative B Direct Criteria Emissions, 4 mtpy .......................................................4-33

Table 4.3-23 Background Concentration Values ...............................................................................4-36

Table 4.3-24 Minimum & Maximum Impacts 2014 Ambient Analysis...........................................4-37

Table 4.3-25 Predicted Criteria Emissions, Alternative B................................................................4-39

Table 4.3-26 Predicted Criteria Emissions Compared to NEI, Alternative B .............................4-41

Table 4.3-27 GHG Coal Combustion Emissions, Alternative B.....................................................4-42

Table 4.3-28 Predicted Ozone Precursor Emissions Rates, Alternative B...................................4-43

Table 4.3-29 TRI Reported Atmospheric Mercury Emissions, Craig Generating Station ........4-44

Table 4.3-30 Potential Coal Comb. Merc. Emissions, Craig Gen. Sta. TRI Actual Emissions..4-44

Table 4.3-31 Approximate Mercury Emissions from the Craig Generating Station Based on TRI 

Actual Emissions, Alternative B .....................................................................................4-45

Table 4.3-32 2009 Western Counties Particulate Monitor Concentrations...............................4-48

Table 4.3-33 2010 Western Counties Particulate Monitor Concentrations...............................4-49

Table 4.3-34 2010 Western Counties Ozone Monitor Concentrations......................................4-49

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Table 4.3-35 2011 Western Counties Particulate Monitor Concentrations...............................4-50

Table 4.3-36 2011 Western Counties Ozone Monitor Concentrations......................................4-51

Table 4.3-37 2012 Western Slope Particulate Monitor Concentrations .....................................4-52

Table 4.3-38 2012 Western Counties Ozone Monitor Concentrations......................................4-52

Table 4.3-39 2013 Western Slope Particulate Monitor Concentrations .....................................4-53

Table 4.3-40 2013 Western Slope Ozone Monitor Concentrations............................................4-53

Table 4.3-41 Actual Coal Shipped via Rail 2007-2014 ......................................................................4-54

Table 4.3-42 Railcar and Rail Maintenance Emission Estimates (tpy)............................................4-54

Table 4.3-43 Criteria Pollutant Emissions Rates................................................................................4-55

Table 4.3-44 GHG Coal Combustion Emissions from the Craig Generating Station...............4-56

Table 4.3-45 Ozone Precursor Emissions Rates Based on the 2013 Craig Generating Station 

CDPHE Reported Emissions..........................................................................................4-57

Table 4.5-1 Summary of Pre-2007 Water Monitoring Data for Selected Parameters............4-62

Table 4.5-2 Stream Flow Data Summary...........................................................................................4-64

Table 4.5-3 Summary of Post-2007 Water Monitoring Data for Selected Parameters..........4-65

Table 4.6-1 Impacts to Previously Undisturbed Vegetation, Alternative A...............................4-69

Table 4.6-2 Previous Impacts to Previously Undisturbed Vegetation, Alternative B ..............4-70

Table 4.9-1 Disturbance to GSG Habitat, Alternative A...............................................................4-79

Table 4.9-2 Previous Disturbance to GSG Habitat.........................................................................4-84

Table 4.10-1 NRHP-Eligible and “Needs Data” Cultural Resource Sites within APE ...............4-88

Table 4.19-1 Impacts to Grazing Allotments, Alternative A........................................................ 4-103

Table 4.20-1 Disturbance to Soil Types, Alternative A................................................................. 4-105

Table 4.20-2 Disturbance to Soil Types in the Project Area, Alternative B............................. 4-106

Table 5.4-1 Criteria Pollutant APEN Annual Emissions...................................................................5-6

Table 5.4-2 2011 Criteria Pollutants by County (tpy)......................................................................5-6

Table 5.4-3 Cumulative Emissions from Criteria Pollutants (tpy) .................................................5-8

Table 5.4-4 Criteria Pollutants as Percentage of 2011 Regional Criteria Pollutant Emissions 5-9

Table 5.4-5 Cumulative Emissions from Greenhouse Gases (metric tonnes/yr).......................5-9

Table 5.4-6 GHG Emissions as Percentage of State and National Emissions (mmt/yr)..........5-10

Table 5.4-7 Cumulative Emissions of Hazardous Air Pollutants (tpy) ........................................5-10

Table 5.4-8 HAP Emissions as Percentage of State and National Emissions.............................5-10

Table 5.4-9 Cumulative Emissions of Criteria Pollutants - 2007 (tpy) .......................................5-11

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Table 5.4-10 2007 Criteria Pollutants as Percentage of 2011 Regional Criteria Pollutant 

Emissions.............................................................................................................................5-11

Table 5.4-11 Cumulative Emissions of Criteria Pollutants - 2008 (tpy)........................................5-12

Table 5.4-12 2008 Criteria Pollutants as Percentage of 2011 Regional Criteria Pollutant 

Emissions.............................................................................................................................5-12

Table 5.4-13 Cumulative Emissions of Criteria Pollutants - 2009 (tpy)........................................5-12

Table 5.4-14 2009 Criteria Pollutants as Percentage of 2011 Regional Criteria Pollutant 

Emissions.............................................................................................................................5-12

Table 5.4-15 Cumulative Emissions of Criteria Pollutants - 2010 (tpy)........................................5-13

Table 5.4-16 2010 Criteria Pollutants as Percentage of 2011 Regional Criteria Pollutant 

Emissions.............................................................................................................................5-13

Table 5.4-17 Cumulative Emissions of Criteria Pollutants - 2011 (tpy)........................................5-13

Table 5.4-18 2011 Criteria Pollutants as Percentage of 2011 Regional Criteria Pollutant 

Emissions.............................................................................................................................5-13

Table 5.4-19 Cumulative Emissions of Criteria Pollutants - 2012 (tpy)........................................5-14

Table 5.4-20 2012 Criteria Pollutants as Percentage of 2011 Regional Criteria Pollutant 

Emissions.............................................................................................................................5-14

Table 5.4-21 Cumulative Emissions of Criteria Pollutants - 2013 (tpy)........................................5-14

Table 5.4-22 2013 Criteria Pollutants as Percentage of 2011 Regional Criteria Pollutant 

Emissions.............................................................................................................................5-14

Table 5.4-23 Cumulative Emissions of Criteria Pollutants - 2014 (tpy)........................................5-15

Table 5.4-24 2014 Criteria Pollutants as Percentage of 2011 Regional Criteria Pollutant 

Emissions.............................................................................................................................5-15

Table 5.4-25 Cumulative Emissions of Criteria Pollutants – 4 Million (tpy)................................5-15

Table 5.4-26 4 Million Throughput Criteria Pollutants as Percentage of 2011 Regional Criteria 

Pollutant Emissions...........................................................................................................5-15

Table 5.4-27 Cumulative Emissions of Greenhouse Gases (metric tonnes CO2e/yr)...............5-16

Table 5.4-28 Cumulative Emissions of Greenhouse Gases (metric tonnes CO2e/yr)..............5-16

Table 5.4-29 GHG Emissions as Percentage of State and National Emissions 2007-2014.......5-16

Table 5.4-30 GHG Emissions as Percentage of State and National Emissions (4 mt)...............5-16

Table 5.4-31 Cumulative Emissions of Hazardous Air Pollutants (tpy) ........................................5-17

Table 5.4-32 Regional NAAQS Comparison from CARMMS Data...............................................5-19

Table 6.2-1 Participants from Cooperating Agencies........................................................................6-3

Table 6.3-1 Office of Surface Mining Reclamation and Enforcement.............................................6-4

Table 6.3-2 Consultants...........................................................................................................................6-4

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project TOC-12

Mining Plan Modification Environmental Assessment
Table of Contents and Acronyms

List of Figures

Figure 1-1 Regional Location Map .....................................................................................................1-3

Figure 2-1 Project Area .......................................................................................................................2-3

Figure 2-2 Alternative A Mine Components and Proposed Disturbance Area ......................2-6

Figure 2-3 Alternative B PR02 as Revised......................................................................................2-17

Figure 3-1 Air Quality Region.............................................................................................................3-5

Figure 3-2 Onsite Meteorological Monitoring ................................................................................3-6

Figure 3-3 Class I Areas.....................................................................................................................3-11

Figure 3-4 Regional Air Quality Monitoring..................................................................................3-14

Figure 3-5a Hydrology..........................................................................................................................3-27

Figure 3-5b Hydrology..........................................................................................................................3-28

Figure 3-6 Vegetative Communities................................................................................................3-35

Figure 3-7 Big Game Range – Mule Deer and Pronghorn..........................................................3-42

Figure 3-8 Big Game Range – Elk.....................................................................................................3-43

Figure 3-9 Colorado River Fish Habitat.........................................................................................3-50

Figure 3-10 Greater Sage-grouse Habitat........................................................................................3-53

Figure 3-11 Soils.....................................................................................................................................3-72

Figure 4-1 Modeled Period Windrose............................................................................................4-35

Figure 4-2 Geographic Location of Modeled Sources ................................................................4-38

Figure 5-1 Air and Climate Resources CIAA..................................................................................5-7

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project TOC-13

Mining Plan Modification Environmental Assessment
Table of Contents and Acronyms

Abbreviations and Acronyms

AADT average annual daily traffic

ACHP Advisory Council on Historic Preservation

AERMAP AERMOD Mapping Program

AERMET AERMOD Meteorological Preprocessor

AERMOD American Meteorological Society/Environmental 

Protection Agency Regulatory Model

af/yr acre-feet per year

amsl above mean sea level

ANFO ammonium nitrate fuel oil

APCD Air Pollution Control Division

APE Area of Potential Effect 

APEN Air Pollution Emission Notice

APLIC Avian Power Line Interaction Committee 

AQCR Air Quality Control Region

AQRV Air Quality Related Values

ASLM Assistant Secretary, Land and Minerals Management

AUM animal unit month

AVF alluvial valley floor

BART Best Available Retrofit Technology

BCC Birds of Conservation Concern

bcy bank cubic yards

bhp brake horsepower

BLM Bureau of Land Management

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project TOC-14

Mining Plan Modification Environmental Assessment
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BMP Best Management Practices

CAA Clean Air Act

CARMMS Colorado Air Resources Management Modeling Study

CCIA Colorado Commission of Indian Affairs

CCRs Coal combustion residuals

CDPHE Colorado Department of Public Health and 

Environment 

CDRMS Colorado Division of Reclamation Mining and Safety

CEQ Council on Environmental Quality

cfs cubic feet per second

CFR Code of Federal Regulations

CH4 methane 

CIAA cumulative impact analysis area

CNHP Colorado Natural Heritage Programs 

CO carbon monoxide

CO2 carbon dioxide

CO2e carbon dioxide equivalent

COA Conditions of Approval

Colowyo Colowyo Coal Company

CPW Colorado Parks and Wildlife 

cv coefficient variation

CWA Clean Water Act

cy cubic yards

DAU Data Analysis Unit

dB decibel

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project TOC-15

Mining Plan Modification Environmental Assessment
Table of Contents and Acronyms

dBA decibel-A weighted

DM Departmental Manual

DNR Department of Natural Resources

DOI Department of Interior

DOT Department of Transportation

DPF diesel particulate filter

DQO data quality objectives

dv deciview

EA Environmental Assessment

EER Exceptional Events Rule

EGU electric generating unit

EIS Environmental Impact Statement

ERMA extensive recreation management area

ERPI Electric Research Policy Institute

ESA Endangered Species Act

FCLAA Federal Coal Leasing Amendments Act 

FEL front end loader

FEM federal equivalent method

FHA Federal Housing Administration

FLPMA Federal Land Policy and Management Act

FNCA Federal Noise Control Act

FONSI Finding of No Significant Impact

FRAN upper limit on the meander factor

FRM federal reference method

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project TOC-16

Mining Plan Modification Environmental Assessment
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FWPCA Federal Water Pollution Control Act

GHG greenhouse gase

GHGRP Greenhouse Gas Reporting Program

GHMA general habitat management area

gpm gallons per minute

GSG greater sage-grouse

GSGWG Greater Sage-Grouse Working Group

GWP global warming potential

GRP gross regional product

HAP Hazardous Air Pollutant

IMPROVE Interagency Monitoring of Protected Visual 

Environments

IPPC Intergovernmental Panel on Climate Change 

kV kilovolt

Leq equivalent sound level

LOWWIND2 low wind speed option 2

LSFO Little Snake Field Office

LSRMP Little Snake Resource Management Plan

MATS Mercury and Air Toxics Standards

MBTA Migratory Bird Act 

MDN mercury deposition network

MFP Management Framework Plans

MLA Mineral Leasing Act

MMPA Mining and Minerals Policy Act 

mmt million metric tons 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project TOC-17

Mining Plan Modification Environmental Assessment
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MPDD mining plan decision document

MSHA Mine Safety and Health Act

mt metric ton

mtpy million tons per year

m/s meters per second

NAAQS National Ambient Air Quality Standards

NAD83 North American Datum 1983

NAGPRA Native American Graves Protection and Repatriation 

Act

NCDC National Climate Data Center

NED National Elevation Dataset

NEI National Emission Inventory

NEPA National Environmental Policy Act

NESHAP National Emissions Standards for Hazardous Air 

Pollutants

NHPA National Historic Preservation Act

NO2 nitrogen dioxide

NO3- nitrate

N2O nitrous oxide

NPDES National Pollutant Discharge Elimination System

NRCS Natural Resources Conservation Service

NRHP National Register of Historic Places

NSPS New Source Performance Standards

O3 ozone

OHV off-highway vehicle

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project TOC-18

Mining Plan Modification Environmental Assessment
Table of Contents and Acronyms

OSAC Office of the State Archaeologist at History Colorado 

OSHA Occupational Safety and Health Administration 

OSMRE Office of Surface Mining Reclamation and Enforcement

PAH polycyclic aromatic hydrocarbon

PAP Permit Application Package

PBO programmatic biological opinion

PCE primary constituent element

PEL permissible exposure limit

PFYC Potential Fossil Yield Classification

PHMA preliminary habitat management area

PM2.5 particulate matter 2.5 microns

PM10 particulate matter 10 microns

ppb parts per billion

ppm parts per million

PR02 Permit Revision 02

PSD Prevention of Significant Deterioration

QAPP Quality Assurance Project Plan

R2P2 Resource Recovery and Protection Plan

RCRA Resource Conservation and Recovery Act 

RFD reasonably foreseeable development

RIPRAP Recovery Implementation Program Recovery Action 

Plan

RMP Resource Management Plan

ROD Record of Decision 

SCC social cost of carbon

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SCR Selective Catalytic Reduction

SDWA Safe Drinking Water Act

SEM Scanning Electron Microscopy

SHPO State Historic Preservation Office

SIP State Implementation Plan

SLB State Land Board

SMCRA Surface Mining Control and Reclamation Act

SNCR Selective Non-Catalytic Reduction

SO2 sulfur dioxide

SO4

2

- sulfate

SPCC spill prevention, control, and countermeasures

SRMA special recreation management area

T&E threatened and endangered 

TDS total dissolved solids

tpy tons per year

TRI Toxic Release Inventory

TSCA Toxic Substances Control Act

TSS Total suspended solids

TWA8 8 hour time-weighted average

μg/g microgram per gram

μg/l microgram per liter

USACE U.S. Army Corps of Engineers

USDA U.S. Department of Agriculture

USFWS U.S. Fish and Wildlife Service

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USGS U.S. Geological Survey

VER valid existing rights

VMT vehicle miles travel

VOC volatile organic compound

VRI visual resource inventory

VRM Visual Resource Management

WOTUS Waters of the U.S.

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OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project TOC-22

Mining Plan Modification Environmental Assessment
Chapter 1 – Purpose and Need

CHAPTER 1 PURPOSE AND NEED

1.1 INTRODUCTION

This Environmental Assessment (EA) has been prepared by the Office of Surface Mining 

Reclamation and Enforcement (OSMRE), Western Region Office, with assistance from the 

following cooperating agencies: the Bureau of Land Management (BLM), Little Snake Field Office 

(LSFO); the State of Colorado, Department of Natural Resources (DNR) (including the 

Executive Director’s Office, Colorado Division of Reclamation Mining and Safety (CDRMS), 

Colorado Division of Parks and Wildlife (CPW), and Colorado State Land Board (SLB)); and 

Moffat County. Because of a recent court decision issued on May 8, 2015, WildEarth Guardians 

v. U.S. Office of Surface Mining et al., Case 1:13-cv-00518-RBJ (D. Colo. 2015), which is requiring 

subsequent analysis, this EA reevaluates the environmental impacts resulting from a mining plan 

modification for the South Taylor/Lower Wilson Permit Expansion Area (the Project). The 

Project was originally proposed by the Colowyo Coal Company, L.P. (Colowyo) in 2006, and 

approved by the U.S. Department of the Interior (DOI) Assistant Secretary, Land and Minerals 

Management (ASLM) in 2007, pursuant to the requirements of the Mineral Leasing Act of 1920, 

as amended (MLA), and the implementing regulations. The Colowyo Coal Mine is located 

approximately 26 miles (42 kilometers [km]) southwest of Craig, Colorado and 22 miles

(35 km) north-northeast of Meeker, Colorado, west of Colorado Highway 13 in southeast 

Moffat and northern Rio Blanco Counties, Colorado (Figure 1-1). 

The National Environmental Policy Act of 1969 (NEPA) requires Federal agencies to disclose to 

the public the potential environmental impacts of projects they authorize and to make a 

determination as to whether the analyzed actions would “significantly” impact the environment. 

“Significantly” is defined by NEPA and is found in Title 40 Code of Federal Regulations (CFR)

1508.27. If OSMRE determines that this Project would have significant impacts following the 

analysis in the EA, then an Environmental Impact Statement (EIS) would be prepared for the 

Project. If OSMRE determines that the potential impacts would not be “significant,” OSMRE 

will prepare a “Finding of No Significant Impact” (FONSI) statement to document this finding, 

and accordingly would not prepare an EIS. 

On July 3, 2006, Colowyo proposed to extend existing mining operations on Federal leases 

COC 29225 and COC 29226 (under previous permit revisions and mining plan modification

approvals) into the remainder of those Federal coal leases. The Project also included extending 

the mining operation into undeveloped Federal coal lease COC 012347601, along with 

additional private lands, within the Lower Wilson Area. At that time, Colowyo did not propose

to mine in the Lower Wilson area but noted that this area may be proposed for mining in the 

future. OSMRE prepared a supplemental EA for the Project and, based on that EA, reached a 

FONSI on May 8, 2007.

CDRMS approved a Mine Permit Revision 02 (PR02), which became final on June 8, 2007 in 

accordance with its responsibilities under the Surface Mining Control and Reclamation Act of 

1977 (SMCRA). The DOI ASLM, in accordance with the MLA, approved Colowyo’s mining plan 

modification for the Project on June 15, 2007, based on a recommendation from OSMRE for 

approval of the Project. In 2008, Colowyo commenced mining in the Project Area in 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 1-1 

Mining Plan Modification Environmental Assessment
Chapter 1 – Purpose and Need

accordance with its state mine permit and Federal mining plan modification approvals. To date, 

mining and reclamation operations under PR02 have been ongoing in the approved permit area.

This EA has been prepared in accordance with the following: NEPA and the Council on 

Environmental Quality (CEQ) regulations for implementing NEPA (40 CFR 1500-1508); the 

DOI’s regulations for implementation of NEPA (43 CFR Part 46); the DOI’s Departmental 

Manual (DM) Part 516; and OSMRE’s Directive REG-1, Handbook on Procedures for 

Implementing the National Environmental Policy Act of 1969 (OSMRE 1989). Information 

gathered from the public; Federal, state, and local agencies; Colowyo; and publicly available 

literature, as well as in-house OSMRE sources such as Colowyo’s Permit Application Package 

(PAP), were used in the preparation of this EA.

1.2 BACKGROUND

Coal has been mined on a commercial scale in the Colowyo Coal Mine area for over 100 years. 

Coal was mined by underground mining techniques continuously until 1974 when the 

underground mines closed. In 1977, Colowyo initiated its first surface mining operation at the 

Colowyo Coal Mine, to access thinner coal seams located closer to the surface than the seams 

historically developed through underground mining. 

In 1979, BLM completed the Final EIS for the Federal Coal Management Program and the 

Secretary of the Interior adopted a new program for the management of coal resources on 

Federal lands. The potential environmental impacts of leasing Federal coal resources in 

Colorado and Wyoming were analyzed in the Final Green River - Hams Fork Regional Coal EIS 

(BLM 1980). 

Colowyo subsequently obtained rights to the additional Federal coal leases and a state lease to 

expand its coal reserve base and ensure continuity of mining. Three Federal leases are included 

in the Project. Lease COC 012347601 was issued by BLM in December 1966 to Utah 

International Inc., and assigned to Colowyo in March 1994. In May 1982, BLM issued lease 

COC 29225 to Utah International, and approved assignment of the lease to Colowyo in March 

1994. Lease COC 29226 was issued by BLM in March 1983 to Utah International and also 

assigned to Colowyo in March 1994. 

To plan ahead for the depletion of coal reserves and ensure continued mining operations, 

Colowyo submitted PR02 to CDRMS in 2006 to revise the PAP and expand the approved 

boundary of their existing SMCRA permit. The Project included approximately 2,223 acres of 

Federal surface estate and approximately 5,219 acres of Federal mineral estate in the Federal 

coal leases that are managed by the BLM. The Project also included approximately 3,827 acres 

of surface estate privately owned by Colowyo and approximately 831 acres of mineral estate 

that are privately owned by another entity. No state lands were included in the Project. The 

revision proposed adding approximately 6,050 acres of the combination of private and Federal, 

surface lands and subsurface mineral estate described above to the previously approved permit 

area of 7,531 acres, for a new total of 13,581.15 acres within the expanded permit area. 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 1-2 

Mining Plan Modification Environmental Assessment
Colorado

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The

Project

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UV13

UV13

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UV13

UV394

UV318

UV317

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Colowyo

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1N 91W

4N 88W

5N 92W

4N 90W

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4N 96W

3N 94W

7N 95W

3N 92W 3N 88W

7N 90W

2N 90W

7N 93W

7N 89W

2N 93W

6N 91W

2N 96W

6N 94W

1N 89W

6N

88W

1N 94W

5N 95W

1N 92W

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4N 89W

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7N 96W

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6N 92W

6N 95W

5N 88W

2N 88W

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Craig

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Garfield

Rio Blanco

Moffat

Rio Blanco

Moffat

Routt

Rio Blanco

Routt

Regional Location Map

1-1

Colowyo Coal Mine, South Taylor/Lower Wilson

Permit Expansion Area Mining Plan Modification

Environmental Assessment

Notes

1.

2.

0 4 8

miles

Approved SMCRA

Permit Area

"d Craig Generating

Station

Railroad

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Township Boundary

County Boundary

($$ ̄

1:253,440 (At original document size of 11x17)

Disclaimer: Figure prepared for OSMRE by Stantec. Stantec assumes no responsibility for data supplied in electronic format. The recipient accepts full responsibility for verifying the accuracy and completeness of the data. The recipient releases Stantec, its officers, employees, consultants and agents, from any and all claims arising in any way from the content or provision of the data.

Rio Blanco & Moffat Counties

Colorado

Coordinate System: NAD 1983 UTM Zone 13N

Basemap: Content may not reflect National Geographic's

current map policy. Sources: National Geographic, Esri,

DeLorme, HERE, UNEP-WCMC, USGS, NASA, ESA, METI, NRCAN,

GEBCO, NOAA, increment P Corp.

Project 

Location

Project Location

Project

Figure No.

Title
Chapter 1 – Purpose and Need

PR02 and the mining plan modification for the Project, approved by CDRMS and the ASLM 

respectively in 2007, permitted Colowyo to mine 43 million tons of coal, produce at a rate of 

up to 6 million tons per year (mtpy) over the period from 2008 to 2017 and disturb a total of 

1,562 acres, including 1,180.7 acres of new surface disturbance, and 381.3 acres of disturbance of 

lands that had already been disturbed under previous permit approvals1

. PR02 also included baseline 

soils, vegetation, and hydrology information for a possible future Lower Wilson Pit to 

potentially be developed in the northwestern portion of the Project. Development of the 

possible future Lower Wilson Pit would include Federal lease COC 012347601. While 

Colowyo provided baseline information for this area, no mine plan or discussion of any mining 

operations, including disturbed and affected acreages, were proposed by Colowyo in their PAP 

for PR02. CDRMS included several stipulations attached to the approved PR02 regarding 

additional investigations that Colowyo would need to conduct and information submittals they 

would need to provide for CDRMS to consider for a possible future Lower Wilson Pit. 

CDRMS also stipulated that no disturbance was approved for the Lower Wilson Area under 

the approved PR02. Since 2007, Colowyo has not proposed development of the Lower Wilson 

Pit and has no future plans to initiate that proposal. As a result, no surface disturbance, mining 

or related operations have or are planned to occur on Federal lease COC 012347601, and it is 

not included in descriptions below of past, current, or reasonably foreseeable future 

operations. 

Colowyo Coal Company L.P., operator of the Colowyo Coal Mine, is a limited partnership 

which is indirectly owned by Western Fuels – Colorado. Western Fuels - Colorado is owned 

by Tri-State Generation & Transmission Association, Inc. The mine produces coal from the 

South Taylor Pit located on Federal coal leases COC 29225 and COC 29226. Coal has been 

produced from the South Taylor Pit since 2008. The Section 16 and West pits were also mined 

at various levels between 2008 and 2013 and 2014, respectively, under previous CDRMS 

approvals. Colowyo operates the existing Colowyo mine under Coal Mining Permit number C1981-019 issued by CDRMS in accordance with their Colorado State Coal Regulatory Program 

(30 CFR Part 906) approved under SMCRA. Currently, the Colowyo Coal Mine produces 

approximately 2.3 mtpy and provides coal primarily to the Craig Station located in Craig, 

Colorado, approximately 26 miles (42 km) northeast of the mine. However, the mine has sold 

coal on the open market to several organizations including, but not limited to, Arizona Electric 

Power Cooperative, American Electric Power, Celanese, City of Colorado Springs, Coleto 

Creek, Coors Energy, Entergy, Public Service Company of Colorado, and the Salt River Project. 

Colowyo actively markets its coal. Once an inquiry is received from an interested buyer, 

Colowyo sends a small sample of coal so that test burns can be conducted, which may lead to a 

future contract. Contracts typically range in length from one time only, on the spot sales, to 

about three years. Once contracts are in place, Colowyo ships coal to customers via an on-site 

rail spur connected to a Union Pacific main rail line that can accommodate coal shipments to 

anywhere in the country.

1 Italicized text denotes language inserted either in response to comments received (see 

Appendix F) or to clarify or update a topic. If you require additional details regarding the 

changes applied please contact the OSMRE Field Operations Branch Manager at (303) 293-

5035.

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 1-4 

Mining Plan Modification Environmental Assessment

 
Chapter 1 – Purpose and Need

1.2.1 Statutory and Regulatory Background

For new mining plans, OSMRE prepares a mining plan decision document (MPDD) in support of 

its recommendation to the ASLM. For existing approved mining plans that are proposed to be 

modified, as is the case here, OSMRE prepares a MPDD for a mining plan modification. The 

ASLM reviews the MPDD and decides whether or not to approve the mining plan modification, 

and, if approved, what conditions, if any, may be needed. Pursuant to 30 CFR 746.13, OSMRE’s

recommendation is based, at a minimum, upon:

• The PAP;

• Information prepared in compliance with NEPA, including this EA;

• Documentation assuring compliance with the applicable requirements of Federal laws, 

regulations and executive orders other than NEPA;2

• Comments and recommendations or concurrence of other Federal agencies and the 

public; 

• Findings and recommendations of the BLM with respect to the Resource Recovery and 

Protection Plan (R2P2), Federal lease requirements, and the MLA; 

• Findings and recommendations of CDRMS with respect to the mine permit application 

and the Colorado State program; and, 

• The findings and recommendations of the OSMRE with respect to the additional 

requirements of 30 CFR Chapter VII, Subchapter D.

1.3 PURPOSE AND NEED

1.3.1 Need

Coal mining operators must have a mining plan approved by the ASLM to mine federal coal. 

30 CFR 746.11. OSMRE is the agency responsible for making a recommendation to the ASLM 

regarding a decision on proposed mining plan modifications. 30 CFR 746.13. Colowyo is 

presently operating under a surface mining plan modification approved in 2007 that allows it to 

mine federal coal from the South Taylor/Lower Wilson Expansion Area in accordance with the 

surface mining permit issued by CDRMS. Under state regulations, surface mining and 

underground mining are permitted separately and subject to differing requirements (CDRMS 

2005). CDRMS has approved the Colowyo Mine only for surface mining (Colowyo 2013). 

On May 8, 2015, the U.S. District Court for the District of Colorado found various NEPA 

violations in connection with Interior’s 2007 approval of a mining plan modification for the 

South Taylor/Lower Wilson Expansion Area. See WildEarth Guardians v. U.S. Office of Surface 

2 In order to assist with assuring compliance with other Federal laws, regulations and executive 

orders, OSMRE also reviews, at a minimum, the following documents to make its 

recommendation to the ASLM: information/correspondence concerning the U.S. Fish and 

Wildlife Service (USFWS) Section 7 consultation for threatened and endangered (T&E) species 

potentially affected by the proposed mining plan under the Endangered Species Act of 1973

(ESA) (USFWS 2006 and 2007), and the National Historic Preservation Act of 1966 (NHPA) 

“Section 106” consultations for the affected area (CHS 2007). 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 1-5 

Mining Plan Modification Environmental Assessment

 
Chapter 1 – Purpose and Need

Mining et al., Case 1:13-cv-00518-RBJ (D. Colo. 2015). The court ordered DOI to complete 

additional NEPA analysis (complete with public participation) within 120 days, indicating that 

the Secretary’s approval of the 2007 mining plan modification for Colowyo would be vacated if 

DOI does not timely complete the required analysis. As a result, OSMRE has identified a need 

for it to re-evaluate its previous mining plan modification recommendation for this area based, 

in part, on the PAP submitted to OSMRE and CDRMS and for the ASLM to issue a new 

decision whether to approve, disapprove, or approve the mining plan modification with 

conditions. 30 CFR 746.14. 

1.3.2 Purpose

The purpose of this federal action is to re-evaluate the environmental effects of the currently 

approved coal mining in the South Taylor/Lower Wilson Permit Expansion Area, PR02, to assist 

OSMRE in developing a new recommendation for the ASLM to make a new decision on the 

mining plan modification for this area.

1.4 RELATIONSHIP TO STATUTES, REGULATIONS, AND

OTHER AGENCY PLANS

1.4.1 Statutes and Regulations

The following key laws, as amended, establish the primary authorities, responsibilities, and 

requirements for developing Federal coal resources: 

- Mineral Leasing Act of 1920 (MLA)

- National Historic Preservation Act of 1966 (NHPA)

- National Environmental Policy Act of 1969 (NEPA)

- Mining and Minerals Policy Act of 1970 (MMPA) 

- Clean Air Act of 1970 (CAA)

- Clean Water Act of 1972 (CWA)

- Endangered Species Act of 1973 (ESA)

- Colorado Surface Coal Mining Reclamation Act of 1979 

- Federal Land Policy and Management Act of 1976 (FLPMA)

- Federal Coal Leasing Amendments Act of 1976 (FCLAA) 

- Surface Mining Control and Reclamation Act of 1977 (SMCRA) 

The MLA and FCLAA provide the legal foundation for the leasing and development of Federal 

coal resources. BLM is the Federal agency delegated the authority to offer Federal coal 

resources for leasing and to issue leases. The MMPA declares that it is the continuing policy of 

the Federal government to foster and encourage the orderly and economic development of 

domestic mineral resources. In that context, BLM complies with FLPMA to plan for multiple 

uses of public lands and determine those lands suitable and available for coal leasing and 

development. Through preparation of land use plans and/or in response to coal industry 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 1-6 

Mining Plan Modification Environmental Assessment
Chapter 1 – Purpose and Need

proposals to lease Federal coal, BLM complies with NEPA to disclose to the public the potential 

impacts from coal leasing and development, and also complies with the NHPA, CAA, CWA, 

ESA and other environmental laws to ensure appropriate protection of other resources. BLM 

then makes the lands that are determined suitable for coal development available for leasing. 

BLM is also responsible for ensuring that the public receives fair market value for the leasing of 

Federal coal. Once a lease is issued, BLM ensures that the maximum economic recovery of 

coal is achieved during the mining of those Federal leases and ensures that waste of Federal coal 

resources is minimized through review and approval of a mine’s R2P2 as required under the 

MLA. BLM implements its responsibilities for leasing and oversight of coal exploration and 

development under its regulations at CFR, Title 43, Public Lands, Subtitle B, Chapter II, BLM, 

Department of the Interior, Subchapter C – Minerals Management, Parts 3400 – 3480 (43 CFR 

Parts 3400-3480). 

SMCRA provides the legal framework for the Federal government to regulate coal mining by 

balancing the need for continued domestic coal production with protection of the environment 

and ensuring the mined land is returned to beneficial use when mining is finished. OSMRE was 

created in 1977 under SMCRA to carry out and oversee those Federal responsibilities. OSMRE 

implements its MLA and SMCRA responsibilities under regulations at CFR Title 30 - Mineral 

Resources, Chapter VII - Office of Surface Mining Reclamation and Enforcement, Department of 

the Interior, Subchapters A-T, Parts 700-955. 

As provided for under SMCRA, OSMRE works with coal producing states to develop their own 

regulatory programs to permit coal mining. Once a regulatory program is approved for a state, 

OSMRE steps into an oversight role. OSMRE has approved CDRMS’s coal regulatory program, 

and as a result, CDRMS manages its own program under the Colorado Surface Coal Mining 

Reclamation Act of 1979 (30 CFR 906.10). CDRMS has the authority and responsibility to 

make decisions to approve surface coal mining permits and regulate coal mining in Colorado 

under Regulations of the Colorado Mined Land Reclamation Board for Coal Mining (revised 

09/14/2005). 

1.4.2 Other Agency Plans

The BLM LSFO manages approximately 1.3 million surface acres and 1.1 million acres of mineral 

estate in northwest Colorado, including BLM managed surface and mineral estate in the Project 

area. As required by FLPMA, BLM periodically prepares and revises land use plans to 

determine those uses that are suitable and compatible on specific portions of the public lands, 

and under what conditions those uses would be authorized to mitigate potential impacts on 

other resource values and protect human health and safety. In the late 1960’s and early 1970’s, 

BLM prepared Management Framework Plans (MFP) as their land use plans. The MFP, which 

was in effect when the Federal leases for the Project were issued and which guides the BLM 

decisions for proposals on the subject coal leases, was the Williams Fork MFP. 

Subsequent to the Williams Fork MFP, the LSFO approved the 1989 Little Snake Resource 

Management Plan (RMP) and associated Record of Decision (ROD) (1989, LSRMP – ROD) 

(BLM 1989), which superseded the Williams Fork MFP. Then in 2011, BLM approved the LSFO 

RMP and associated ROD (2011, LSFO RMP-ROD) (BLM 2011), which replaced the 1989 

LSRMP-ROD. Colowyo’s leases were issued by BLM in conformance with the decisions of the 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 1-7 

Mining Plan Modification Environmental Assessment
Chapter 1 – Purpose and Need

Williams Fork MFP and therefore were established as valid existing rights (VER) prior to 

approval of the newer RMPs. As is recognized and stated in the 2011 LSFO RMP-ROD, a valid 

existing lease conveys certain rights of development to the leaseholder and a stipulation cannot 

be added after the lease is issued without the consent of both the lessee and lessor. 

Conditions of Approval (COA) and/or Best Management Practices (BMP) required by BLM in 

accordance with the newer RMPs would need to be consistent with the VER granted in existing 

leases. In this context, BLM made subsequent and periodic decisions regarding readjustment of 

the lease terms for each lease as required under the MLA and FCLAA. For each readjustment 

decision, BLM determined whether the lease terms were in conformance with the land use plan 

in effect at the time and in each case BLM determined the leases did conform with the plans. 

Further, OSMRE consulted with the BLM LSFO during the 2007 mining plan modification 

decision process to review and make a recommendation to the ASLM for the decision on the 

PR02 mining plan modification. In a letter dated May 2, 2007, the BLM LSFO determined and 

documented that the R2P2, which BLM approves and which is directly linked to the PR02 

proposal, was in conformance with the 1989 LSRMP-ROD. In the context of this EA, BLM has

again reviewed the Project and, considering VER, confirms the Project is in conformance with 

the 2011 LSFO-ROD. 

1.5 AUTHORIZING ACTIONS

Two separate approvals are needed for a coal mine operator to conduct mining operations on 

lands containing leased Federal coal: 1) a SMCRA mine permit approved by the state regulatory 

authority, in this case, CDRMS; and 2) a mining plan or mining plan modification approved by 

the ASLM in accordance with the MLA. 

1.6 OUTREACH AND ISSUES

Public comments were solicited through multiple methods. OSMRE published legal notices in 

the Rio Blanco Herald Times and the Craig Daily Press on May 21 and 22, 2015, and again on June 

4 and 5, 2015, respectively (Appendix A). The notice described the Project in summary form, 

informed the public that a public outreach meeting for the EA was scheduled for June 10, 2015 

at the Center of Craig facility, and that public comments would be accepted until June 15, 2015. 

The notice was also posted at various public locations in Craig and Meeker. An outreach letter 

describing the Project, announcing the public outreach meeting, and soliciting comments was 

mailed on May 21, 2015, to a total of 98 recipients, including BLM, Indian tribes, state agencies, 

city and county governments, adjacent landowners, and other interested parties. A total of 51 

of the parties receiving the outreach letter, primarily private citizens, had recently expressed 

interest in receiving information on the proposed nearby Collom Mine Expansion project at the 

Colowyo Mine and thus were also included in the public outreach. 

On May 28 and 29, legal notices were again published in the Rio Blanco Herald Times and the 

Craig Daily Press, respectively (Appendix A) informing the public that the meeting location had 

been changed to the Grandstands Building at the Moffat County Fairgrounds. In addition, on 

May 28, a second outreach letter was mailed to the same recipients who received the original 

May 21 letter, informing them of the change in location for the June 10, 2015 outreach meeting.

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 1-8 

Mining Plan Modification Environmental Assessment
Chapter 1 – Purpose and Need

On May 21, 2015, OSMRE published the following Project website, which provided additional 

Project notice, Project information, and comment opportunities: 

http://www.wrcc.osmre.gov/initiatives/colowyoMineSouthTaylor.shtm. 

The public outreach meeting was held on June 10, 2015, at the Grandstands Building, Moffat 

County Fairgrounds, 601 Victory Way in Craig from 4:00 PM until 8:00 PM. Six-hundred and 

thirty-two people attended and 447 submitted comment forms onsite. A total of 1,174 

individuals or organizations submitted a total of 1,432 distinct comments by the end of the 

comment period. 

The following table (Table 1.6-1) summarizes the comment topics by resource category.

Table 1.6-1 Public Outreach Comments Categorized by Resource Topic

Comment 

Category

Number of 

Comments

% of Total 

Comments

Air Quality/ 

Climate Change 155 10.82% 

Grazing 1 0.07%

Reclamation 124 8.66%

Socioeconomic 507 35.40%

Vegetation 1 0.07%

Water 4 0.28%

Wildlife 66 4.61%

Topic Not Clear 

But Supportive of 

the Mine 

564 39.39% 

Topic Not Clear 10 0.70%

Total 1,432 100%

The comments received during the public outreach comment period varied widely but the 

overall majority indicated either direct support for the continuation of Colowyo’s mining 

operation or identified a wide range of benefits of their mining activity. More than a third of 

the comments were statements of support for the continuation of mining at the mine. Another 

roughly third of the comments addressed socioeconomic effects. Some of this group focused 

on the potential for the mine to shut down and the potential adverse socioeconomic effects of 

that action, such as loss of income, on individuals, families, local businesses, and local 

communities. In addition, a number of the latter comments identified the beneficial impacts the 

Colowyo mining operation has historically had on the economy and quality of life in Craig and 

greater northwestern Colorado, such as providing jobs, supporting the need for related 

businesses, and attracting major retail stores to Craig. Other comments addressed the 

beneficial effects of Colowyo’s reclamation efforts on big game and other wildlife through 

improved habitats post mining and that Colowyo’s reclamation operations have been 

recognized through receiving awards. Some of the comments identified the beneficial effects of 

Colowyo’s mining operation on wildlife by providing personal observations of greater wildlife 

numbers within the mine permit boundary than outside the boundary. 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 1-9 

Mining Plan Modification Environmental Assessment
Chapter 1 – Purpose and Need

Commenters also raised several concerns over the potential adverse impacts of the Project on 

a number of resources. Almost 11 percent of the comments addressed air quality, including

climate change. Some expressed anecdotal observations about the air quality in northwest 

Colorado in proximity to the Craig Generating Station, asserting that the quality of the air in 

this area is as good or better as other parts of the state. Others expressed concern about the 

adverse effects of coal combustion on air quality and the need to carefully evaluate and consider 

its impacts. In particular, some commenters identified concerns over the potential impacts on 

air quality from mining operations, coal transportation, and burning coal, including impacts to 

climate change from greenhouse gases (GHGs) and the social costs of carbon emissions. Other 

air quality impact concerns raised by one commenter include: impacts of mining to national 

ambient air quality standards (NAAQS), particularly for ozone; particulate matter and nitrogen; 

and impacts on threatened and endangered fish species in the Yampa River, and their habitats, 

from the associated regional deposition of combustion byproducts such as mercury from the 

Craig Generating Station. Comments also raised concerns over impacts to surface water 

quality especially with regard to possible contributions of the Project to existing water quality 

problems, such as the state identified exceedance of iron standards in the Yampa River.

Comments also identified alternatives to the Project that could be analyzed. These alternatives 

included: reduced mining levels, underground mining, reduced air quality impacts including 

reduced GHGs, and an alternative that would require offsite mitigation or compensation for 

impacts. These alternatives and reasons for dismissing or carrying them forward for analysis 

are addressed in Chapter 2. 

All outreach comments received have been considered and included as appropriate in the 

preparation of this document.

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 1-10

Mining Plan Modification Environmental Assessment
Chapter 2 – Proposed Action and Alternatives

CHAPTER 2 PROPOSED ACTION AND ALTERNATIVES

2.1 Introduction

This chapter describes the alternatives considered and analyzed in detail: Alternative A (the 

Proposed Action), Alternative B (PR02 as Revised), and the No Action Alternative. In addition, 

it identifies alternatives considered but eliminated from detailed analysis. 

Alternative A, the Proposed Action, goes back in time to 2007, as if no mining or related 

surface disturbance for PR02 has yet occurred. This alternative is based on the mining plan 

modification submitted for PR02, which was first analyzed in OSMRE’s EA prepared in May 2007 

and approved by both CDRMS and the ASLM in June 2007 (PR02 as Approved in 2007). This 

unusual approach is necessary to effectively address the court order direction to re-evaluate 

the mining plan modification that OSMRE had previously analyzed under NEPA in 2007. 

Alternative A is described below with the information that would have been available to OSMRE 

back in 2007. PR02 as Approved in 2007 added approximately 6,050 acres to the previously 

approved permit area, (i.e., PR01), extending surface coal mining operations into those portions 

of federal leases COC 29225 and COC 29226 that were not included in PR01. PR02 as 

Approved in 2007 also included undeveloped federal coal lease COC 12347601, along with 

additional private lands, in the Lower Wilson Area. At that time Colowyo indicated this

undeveloped lease may be proposed for surface mining in the future. This Alternative uses the 

assumption that mining would continue under PR02 as Approved in 2007 without any additional 

revisions. In accordance with PR02 as Approved in 2007, mining was planned to be completed 

in 2017 and the South Taylor final pit closure was also planned to commence in 2017.

Since June 2007, however, Colowyo has been mining under PR02 and has already disturbed 

approximately 789 acres of previously undisturbed land over the past 8 years. However, it is 

important to understand that mining is a dynamic process that requires continual collection, 

interpretation, and analysis of new geologic and engineering data as the operation progresses. 

This process results in constant refinement of the geologic and engineering models used for 

planning future mining operations. Changes in mining operations require the company to revise 

the Permit over time through the CDRMS revision process, in order to most efficiently mine 

the coal. Pursuant to its delegated SMCRA permitting authority, CDRMS has approved a 

number of minor revisions to PR02 as Approved in 2007, which have changed the mining and 

reclamation plan approved in 2007 but did not require approval of a mining plan modification by the 

ASLM. 

Alternative B spans the timeframe from 2007, after approval of PR02 and starting with the 

commencement of operations, through the present, inclusive of the mining operations and 

disturbance that have already occurred over the last 8 years. Further, this alternative includes 

the reasonably foreseeable future mining operations to be conducted over the next four years, 

and projected to be completed in 2019 when reclamation would begin. In other words, 

Alternative B is based on PR02 as currently implemented, inclusive of all revisions approved 

between 2007 and the present. In general, when compared with Alternative A, Alternative B

(PR02 as Revised) has a lower production rate, results in less surface disturbance, and recovers 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 2-1 

Mining Plan Modification Environmental Assessment
Chapter 2 – Proposed Action and Alternatives

less coal over the life of the Project. Greater detail regarding the currently approved PR02

(Alternative B), which consists of additional descriptions, maps, and drawings contained in the 

PAP, is available at the Colowyo Mine Administration Office at: 5731 State Highway 13, 

Meeker, CO 81641; the CDRMS office at: 1313 Sherman Street Denver, CO 80203; and the 

OSMRE at: 1999 Broadway, Suite 3320 Denver, CO 80202.

The No Action Alternative, Alternative C, like Alternative B (PR02 as Revised), spans the 

timeframe from when operations commenced in 2007 after the initial approval of PR02, 

through the present, inclusive of the mining operations and disturbance that have already 

occurred. However, under this alternative, the ASLM would not approve the mining plan 

modification for PR02, which would require termination of mining of federal coal in the Project 

Area in September 2015 and immediate reclamation of the Project Area in accordance with the 

permit and federal lease terms. 

For the purposes of this EA, the Project Area boundary (Figure 2-1) includes all areas 

potentially affected by Alternatives A and B. The Project Area boundary also includes all of the 

areas of PR02 that have already been affected since mining development began in 2007, as well 

as portions of non-federal lands previously permitted for mining, such as State Lease 257-13s 

and portions of federal leases COC 29255 and COC 29256, also previously permitted for 

mining. Coal has been actively mined from the Project Area from 2008 until present. Approximately

789 surface acres of previously undisturbed land in the Project Area have already been disturbed

under Alternative B; this accounts for approximately 66.8 percent of the new surface disturbance 

anticipated under Alternative A and 97.5 percent of the new surface disturbance anticipated for 

Alternative B. The Lower Wilson Area has not been proposed for mining under either 

Alternative A or Alternative B and Colowyo indicates that it has no future plans for mining in 

that area.

The Project Area is located immediately west, southwest, and northwest of the mining 

operations occurring in 2007 in the West Pit. The Project Area boundary (Figure 2-1) 

includes the three federal coal leases noted above (COC 012347601, COC 29225, and COC 

29226), and a very small portion of an additional federal lease COD 034365 underlying private

lands owned by Colowyo, portions of State of Colorado lease 257-13s, and other private lands. 

Federal lease COD 034365 was issued in October 1924 and assigned to Colowyo in April 1946.The 

Project Area boundary encompasses 7,115.54 acres and includes all or portions of:

Township (T) 3 North (N), Range (R) 93 West (W), 6th Prime Meridian (PM),

Sections 5, 7, 8, 9, 16, 17, 18, 19, 20, 21, 22, 28, 29, and 30; 

T4N, R93W, 6th PM, Sections 15, 16, 21, 22, 28, 32, and 33. 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 2-2 

Mining Plan Modification Environmental Assessment
Colorado

Mine

Entrance

Gossard

Loadout

UV13

5N 92W

4N 93W

3N 94W 3N 92W

5N 93W

4N 94W

3N 93W

4N 92W

5N 94W

05 06

07 08

17 18

19 20

29 30

01 02 03 04 05 06

07

08 09 10 11 12

13 14 15 16 17

18

19 20 21 22 23 24

26 25 27 28 30 29

01 02 03 04 05 06

07

08 09 10 11 12

13

14 15 16 17

20 21 22 23 24

26 25 27 29 28

07

17

18

19 20

29 30

31 32

07 08 09 10 11 12

13 14 15 16

17

18

19 20

21

22

23

24

25 27 26 28 29 30

31

32 33 34 35 36

07 08 09 10 11 12

13 14 15 16 17 18

19 20 21 22

23

24

25 26

27

28 30 29

31 32 33 34 35 36

31 32

31 32 33 34 35 36

35 36

UV9

UV17

UV51

UV32

UV180

Moffat

Rio Blanco

Project Area

2-1

Colowyo Coal Mine, South Taylor/Lower Wilson

Permit Expansion Area Mining Plan Modification

Environmental Assessment

Notes

1.

2.

0 1 2

miles

Project Area

Approved SMCRA Permit Area

Lease Area

COC 029225

COC 029226

COC 012347601

COD 0034365

257-13s

County Road

Highway

Section Boundary

Township Boundary

County Boundary

Land Status

Bureau of Land Management

Private

State

State, County, City - Park/

Outdoor Rec Areas

($$ ̄

1:63,360 (At original document size of 11x17)

Disclaimer: Figure prepared for OSMRE by Stantec. Stantec assumes no responsibility for data supplied in electronic format. The recipient accepts full responsibility for verifying the accuracy and completeness of the data. The recipient releases Stantec, its officers, employees, consultants and agents, from any and all claims arising in any way from the content or provision of the data.

Coordinate System: NAD 1983 UTM Zone 13N

Basemap: Content may not reflect National Geographic's

current map policy. Sources: National Geographic, Esri,

DeLorme, HERE, UNEP-WCMC, USGS, NASA, ESA, METI, NRCAN,

GEBCO, NOAA, increment P Corp.

Project 

Location

Project Location

Project

Figure No.

Title

Rio Blanco & Moffat Counties

Colorado
Chapter 2 – Proposed Action and Alternatives

The following are the legal descriptions of those portions of the federal leases included within 

the Project Area:

Lease COC 29225

T3N, R93W, 6th P.M.

Section 5: lots 1 and 2, S1/2 NE1/4, SE1/4; 

Section 7: NE1/4NE1/4, S1/2NE1/4, SE1/4;

Section 8; S1/2SE1/4SE1/4, W1/2E1/2, W1/2;

Section 17: All;

Section 18: lots 3 and 4, E1/2, E1/2SW1/4;

Lease COC 29226

T3N, R93W, 6th P.M.

Section 19: lots 1-3, E1/2, E1/2W1/2; 

Section 20: lot 1, N1/2, SW1/4, N1/2SE1/4, SW1/4SE1/4;

Section 21: TR 47 lots 6, 8; lots 1, 3, 5, 7, 10, N1/2, N1/2SW1/4, NW1/4SE1/4;

Section 28: TR 47 lots 4, 5, 8, 12, 13, 15; lots 6, 24;

Section 29: lots 2, 3, 13;

Lease COC 012347601

T4N, R93W, 6th PM

Section 5: SW1/4; E1/2NW1/4;

Section 32: lot 4, S1/2SE1/4; 

Lease COD 034365

T3N, R93W, 6th P.M.

Section 9: S1/2SW1/4SW1/4

2.2 Alternative A – Proposed Action – PR02 as Approved in 2007 

Alternative A reflects Colowyo’s original proposal for mining the South Taylor/Lower Wilson 

Permit Expansion Area as presented to CDRMS in 2006 and approved by CDRMS, OSMRE, and 

the ASLM in 2007, and projects the same level of activity approved in 2007 would continue for 

the life of the Project. The 2007 approved mining plan modification included the following: 

mining approximately 43 million tons of federal coal; mining at a maximum rate of up to 6 mtpy; 

disturbing up to 1,562 acres of surface land within the permit area (Figure 2-2); and 

conducting mining operations from 2008 through 2017. 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 2-4 

Mining Plan Modification Environmental Assessment
Chapter 2 – Proposed Action and Alternatives

2.2.1 Proposed Mine Operation Components in 2007

The operation plan for PR02 as Approved in 2007 included the following mine components and 

facilities:

• One open pit, the South Taylor Pit, to access the coal seams, including by highwall 

mining methods; 

• Two permanent and two temporary stockpile areas to store spoil material removed 

prior to mining for use in backfilling the open pit during reclamation;

• Dispersed facilities necessary to conduct mining operations including: 

o Temporary light use roads;

o Temporary stockpile areas to store topsoil removed from disturbed areas for 

use in reclamation;

o A 69 kilovolt (kV) power line and associated power poles within the area of 

mining operations to power the dragline and shovel; 

o Temporary berms; 

o Waterlines;

o Temporary construction staging areas; 

• Sediment ponds and diversion ditches. 

Colowyo’s original 2006 PAP submittal to CDRMS proposed to disturb a total of approximately 1,562 

acres as described in Table 2.2-1. Most of the proposed disturbance would occur as new disturbance 

both within the applied for expansion area (PR02) and within the existing permit area (PR01), totaling

1,180.7 acres. (Total of Columns (A) + (B) in Table 2.2-1). It is not uncommon that a proposed 

permit expansion project area would overlap with an existing operation, disturbing areas that were 

already disturbed under a previous permit approval. Disturbance within the existing permit area would 

also occur on lands that were: 1) currently disturbed and with no re-grading or ongoing reclamation; 

and 2) previously disturbed and that were re-graded and may also be undergoing reclamation efforts. 

The balance of the Alternative A’s proposed disturbance would occur on lands already disturbed under 

previous permit approvals, as described in 1) and 2) above, totaling 381.3 acres (Total of columns (C) 

+ (E) in Table 2.1-2). Under CDRMS’ SMCRA responsibilities and authority, the agency decides 

whether or not to approve areas of new disturbance (lands not previously approved by CDRMS for 

disturbance) and areas of re-disturbance (lands approved by CDRMS for disturbance under a previous 

permit revision and for which re-grading and/or reclamation activities have begun). PR02 as Approved in 

2007 included a combined total of 1,532.6 acres of new disturbance and re-disturbance acres 

approved by CDRMS. The remaining 29.4 acres of the 1,562 acres proposed for disturbance in 

Colowyo’s 2006 PAP would occur on lands previously approved by CDRMS for disturbance, but for 

which no regrading had yet occurred and also for which no reclamation activities had yet been initiated. 

CDRMS does not consider disturbance for the latter such lands as part of the overall acres of 

disturbance reported when processing permitting actions.

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 2-5 

Mining Plan Modification Environmental Assessment
Colorado

13

3N 94W

3N 93W

03 02

07

08 09 10

11

14

15 16

17

18

19

20 21 22

23

26 27

28

29

30

12

13

24

25

51

Moffat

Rio Blanco

SCS

SCS

SCS

SCS

Alternative A Mine Components

and Proposed Disturbance Area

2-2

Colowyo Coal Mine, South Taylor/Lower Wilson

Permit Expansion Area Mining Plan Modification

Environmental Assessment

Notes

1.

2.

0 2,000 4,000

Feet

Project Area

Approved SMCRA Permit Area

Proposed Disturbance Area

Disturbance not associated with PR 02

Topsoil Stockpile

Sediment Control Structure (SCS)

East Taylor Fill

West Taylor Fill

Temporary Spoil Pile

South Taylor Pit Shell

County Road

Highway

Section Boundary

Township Boundary

County Boundary

Land Status

Bureau of Land Management

Private

State

1:24,000 (At original document size of 11x17)

Disclaimer: Figure prepared for OSMRE by Stantec. Stantec assumes no responsibility for data supplied in electronic format. The recipient accepts full responsibility for verifying the accuracy and completeness of the data. The recipient releases Stantec, its officers, employees, consultants and agents, from any and all claims arising in any way from the content or provision of the data.

Coordinate System: NAD 1983 UTM Zone 13N

Basemap: Content may not reflect National Geographic's

current map policy. Sources: National Geographic, Esri,

DeLorme, HERE, UNEP-WCMC, USGS, NASA, ESA, METI, NRCAN,

GEBCO, NOAA, increment P Corp.

Project 

Location

Project Location

Project

Figure No.

Title

Rio Blanco & Moffat Counties

Colorado
Chapter 2 – Proposed Action and Alternatives

Table 2.2-1 Alternative A Proposed Disturbance Acreage by Project Component

Project 

Component

(A) 

DRMS Approved

New Disturbance 

in the Expanded 

Permit Area

(B) 

DRMS Approved

New Disturbance 

in the Existing 

Permit Area

(C) 

DRMS Approved

Re-Disturbance in 

the Existing

Permit Area

(D) 

Subtotal 

DRMS 

Approved 

Disturbance

(E)

Acres Disturbed

in Previously

Disturbed and

Un-Reclaimed

lands in the 

Existing Permit

Area

(F)

Total Acres

Proposed to be 

Disturbed 

under 

Alternative A

Pit 646.3 162.7 172.1 981.1 0 981.1

East Taylor

Fill 0 59.8 76.2 136.0 0 136.0

West Taylor

Fill 248.9 12.0 0 260.9 0 260.9

Between Fills 8.5 26.7 9.4 44.6 0 44.6

Temporary Fill 0 0 70.2 70.2 0 70.2

West Taylor

Pond 5.7 0 0 5.7 0 5.7

Sec 21 Pond 6.6 0 0 6.6 0 6.6

Sec 28 Pond 2.1 0 0 2.1 0 2.1

Pond Roads 1.4 0 0 1.4 0 1.4

Topsoil 

Stockpiles 0 0 24 24 29.4 53.4

Totals 919.5 261.2 351.9 1,532.6 29.4 1,562

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 2-7 

Mining Plan Modification Environmental Assessment
Chapter 2 – Proposed Action and Alternatives

2.2.2 Methods and Operation

In its original application for PR02, Colowyo proposed to utilize truck/shovel, dragline, and 

highwall surface mining techniques, which it has used in other parts of the mine since 1977.

In general, the following mining operation sequence was proposed to be implemented although 

some activities would occur concurrently or overlap:

• Construct sediment ponds and diversions ditches;

• Strip and stockpile topsoil from areas to be mined and disturbed;

• Begin removing spoil material from the South Taylor Pit area; 

• Develop two temporary spoil stockpiles; 

• Begin reclamation during mining operations;

• Complete mining of the South Taylor Pit; and,

• Complete reclamation.

All truck haul and access routes within the South Taylor/Lower Wilson Permit Expansion Area 

that connect the South Taylor Pit to the existing operation were proposed to be constructed 

as in-pit truck routes. 

Existing mine support facilities, located approximately 3.5 miles (5.6 km) north of the South 

Taylor area, would be used for the mining operation. These existing facilities include an office 

building, machine shop, warehouse, welding shop, tire bay, wash bay, maintenance shop, parking 

lot, explosives storage facility, and an oil and fuel storage area. 

Explosives would be used to fragment the spoil material. Blasting would be conducted in 

accordance with the procedures and specifications presented in the approved surface mining 

permit.

Under this alternative, truck/shovel operations would remove the upper three layers of spoil 

material, and the dragline would remove the final layer of spoil material. The South Taylor Pit 

would be 8,835 feet long by 7,005 feet wide and 580 feet deep covering approximately 981

surface acres. The initial material excavated from the South Taylor Pit (also known as the 

boxcut) would be placed in two permanent valley fills, the East Taylor and West Taylor Fills, 

which would also be designed to contain approximately 60 million cubic yards of spoil material. 

Following development of the boxcut, spoil material from the upper seams, of the South Taylor 

Pit would be hauled to two temporary spoil piles. One would be constructed on top of the 

East Taylor Fill and the other directly east of the East Taylor Fill, within a previously mined and 

reclaimed pit called the Section 16 Pit (Figure 2-2). The dragline spoils would remain in the 

pit. 

Prior to PR02 as Approved in 2007, the average production rate for the Colowyo mine outside 

the Project Area was approximately 4.5 mtpy. PR02 as Approved in 2007 allows a maximum 

production rate of 6.0 mtpy for the life of the Project Area. The time anticipated to mine the 

coal under this Alternative would be approximately ten years, from 2008 to 2017.

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 2-8 

Mining Plan Modification Environmental Assessment
Chapter 2 – Proposed Action and Alternatives

Recovered coal under this Alternative would be trucked to an existing primary crusher and an 

existing coal stockpile located just north of the West Pit. From there coal would be trucked to 

an existing secondary crusher and coal stockpile located approximately four miles (6.4 km) 

north at the Gossard Loadout. From the loadout, coal would be transported to coal markets 

by rail in unit trains, i.e. “a railway train that transports a single commodity directly from 

producer to consumer” (Merriam-Webster 2015). 

Under Alternative A, the proposed reclamation objective would be to restore the disturbed 

areas to the pre-mining use of rangeland, capable of supporting both domestic livestock and 

wildlife. Re-grading and topsoil placement would occur in accordance with the approved 

reclamation plan and while mining is ongoing.

2.2.3 Project Design Features

The surface mining permitting process under the State of Colorado’s coal regulatory program 

requires applicants to incorporate design features into their mining proposals to protect or 

minimize impacts to a wide variety of environmental resources (CDRMS 1980). Examples of 

such environmental resources include water, air, fish, and wildlife. Each PAP submitted to 

CDRMS for a new or revised mining permit is required to contain a number of resource 

specific plans. The resource specific plans describe the proposed mine’s (or proposed mine 

revision’s) design features for reducing or eliminating the potential impacts to various resources

or how those resources will be restored to pre-mining conditions after mining is complete. 

CDRMS reviews the PAP, which includes the required resource specific plans, design features, 

and associated performance standards. If the PAP meets the state standards, CDRMS approves 

the PAP. The CDRMS approval commits the applicant to implementing the design features

contained in the PAP. It is important to note that the design features of the original permit also 

apply to the newly revised permit, unless CDRMS approves any changes to the revised permit 

that would replace older design features.

In Colowyo’s case, CDRMS approved Colowyo’s original surface mining permit in 1982 (C1981-019). PR01 for the West Pit was approved in July 1992, and PR02 for the South 

Taylor/Lower Wilson Permit Expansion Area was approved in June 2007. The PAP, for PR02, 

incorporated new design features, as well as retained the design features that were included in 

the original permit approval and those included in the PR01 approval. A summary of the design 

features to reduce or eliminate potential impacts to environmental resources that were 

incorporated in PR02 as Approved in 2007 and are included in the analysis of Alternative A are

included in Table 2.2-2, and a more detailed description of the design features is included in 

Appendix B. 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 2-9 

Mining Plan Modification Environmental Assessment
Chapter 2 – Proposed Action and Alternatives

Table 2.2-2 Summary of Principal Design Features

Resource Area Measure

Topography

Restore the area to approximate original contours (AOC).

Grade backfilled mining areas to establish a stable post mine topography that blends into 

the undisturbed areas outside the mining limits.

Grade final slopes to not exceed the approximate original pre-mining slope grade.

Grade all final slopes so that overall grades do not exceed 33%.

Blend the highwall into the backfilled material to result in a natural and gradual slope 

change.

For a more detailed description of design features, refer to the Reclamation Plan 

(Appendix B).

Air Quality

Water haul roads as necessary to control fugitive dust. Obtain a CDPHE Air Pollution

Control Division Construction Permit (modification to current permit) (Note: 

Approval conditions are included in Colowyo’s Air Pollution Control Division

permit – such as the Fugitive Dust Control Plan (as an appendix to the permit)). 

For a more detailed description of design features, refer to the Air Quality Control Plan 

(Appendix B).

Water Resources

Construct new sedimentation structures and diversion ditches to control runoff, avoid 

erosion and an increased contribution of sediment load to runoff, and protect 

surface and ground water quality.

Control and monitor the quantity and quality of any discharges from the permit area in 

compliance with the National Pollutant Discharge Elimination System (NPDES) 

Permit (Number CO-0045161 issued by the CDPHE).

Designate stream buffer zones and install sedimentation ponds on the drainages from 

disturbed areas feeding into surface water features.

Retain drainage off the "in-pit" roads in the pit or divert to drainage and sediment 

control structures.

Line channels with rock riprap and install energy dissipaters when necessary.

Seed the entire embankment of all sedimentation ponds, including the surrounding areas 

disturbed by construction, after the embankment is completed.

Design sedimentation ponds to treat the theoretical 10-year, 24-hour storm event and 

contain the theoretical 25-year, 24-hour storm event.

Construct small impoundments on reclaimed areas to collect surface runoff from 

precipitation events and snowmelt from reclaimed areas.

Where practicable, use diversion methods to change the flow of water from 

undisturbed areas so as to bypass the disturbed areas rather than using treatment 

facilities.

Direct all surface runoff from the disturbed areas through sedimentation ponds.

For a more detailed description of design features, refer to the Protection of the 

Hydrologic Balance Section and Performance Standards 4.05 Hydrologic Balance 

(Appendix B).

Vegetation

Manage livestock (cattle) grazing to select against grasses resulting in increased shrubs 

and forbs.

Use elk-proof fencing to preclude access into large blocks of maturing shrub 

populations, especially core areas.

In concert with CPW, use hunting pressure to reduce elk utilization of new reclamation 

areas where it can be incorporated in a safe manner given proximity to active 

mining.

Use orchard grass (Dactylis glomerata) in key reclamation locations to encourage elk to 

move away from maturing shrub populations. 

Implement procedures for micro-habitat development whereby snow catchment is 

encouraged and shrub heavy mixes can be applied.

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 2-10

Mining Plan Modification Environmental Assessment
Chapter 2 – Proposed Action and Alternatives

Resource Area Measure

Vegetation

Interseed shrubs (as necessary as a normal husbandry practice) in areas not exhibiting 

satisfactory establishment of shrubs, but with opportunities (micro-niches) for 

shrub establishment. 

Fence reclaimed areas as appropriate, if necessary, to manage grazing or browsing by 

livestock or wildlife. 

For a more detailed description of design features, refer to the Reclamation Plan 

(Appendix B).

Fish and Wildlife

Revegetate for big game benefit/use.

Construct power lines to Avian Power Line Interaction Committee (APLIC) standards.

Implement construction guidelines for retrofitting existing power poles to protect 

raptors.

Limit vehicle speeds in the mine area to reduce the likelihood of collisions with wildlife.

Provide topographic relief for wildlife habitat. 

Reestablish escape cover, south facing slopes for wintering big game populations and 

small drainages suitable as future location of stockponds, necessary to achieve the 

post-mining land use.

For a more detailed description of features, refer to the Fish and Wildlife Plan 

(Appendix B).

T&E Species

Continue the established practice of clearing areas of thick brush and decadent stands of 

the mountain shrub vegetation within and adjacent to the lease area as part of the 

big game mitigation program production of succulent herbaceous vegetation and 

provide more forage for the Greater sage grouse brood population.

Continue collaboration with CPW for Greater sage grouse studies.

Implement measures required as part of the Endangered Fish Recovery Agreement with 

USFWS.

Cultural Resources Perform pre-disturbance field surveys.

Visual Resources

Restore disturbed areas to original contours.

For a more detailed description of design features, refer to the Reclamation Plan 

(Appendix B).

Soils

Construct a drainage control bench or furrow, where necessary, to slow water flow on 

the longer slopes and minimize erosion.

Provide a buffer zone between the area disturbed by mining and the area where topsoil 

has not been removed. 

Restrict non-essential vehicular traffic from undisturbed area.

Construct topsoil stockpiles with outside slopes no steeper than 3h: 1v. 

Locate topsoil stockpiles to avoid erosion from wind and water and additional 

compaction or contamination.

Protect topsoil stockpiles from wind erosion by planting a perennial mixture as soon as 

conditions allow.

No topsoil stockpiles will be placed in a drainage bottom where external erosion might 

pose a potential threat.

Mark all topsoil stockpiles with identifying signs.

If soil compaction is a problem, rip the soil with a dozer to minimize compaction, assure 

stability, and minimize slippage after topsoil replacement.

Develop concave landforms (to encourage snow entrapment) on a case-by-case basis.

Leave reapplied topsoil in a rough condition to help control wind and water erosion 

prior to seeding. 

For more detailed description of design features, refer to the Reclamation Plan 

(Appendix B).

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 2-11

Mining Plan Modification Environmental Assessment
Chapter 2 – Proposed Action and Alternatives

2.3 Alternative B – PR02 as Revised 

Alternative B reflects the surface disturbance and mining operations that have actually occurred 

in the South Taylor/Lower Wilson Permit Expansion Area since 2007 as the result of 

subsequent revisions to PR02 approved by CDRMS, and those effects that are reasonably 

anticipated to occur throughout the remaining life of the Project under the currently approved 

PR02. In general, when compared with Alternative A, Alternative B (PR02 as Revised) has less 

acreage disturbed, less coal mined, and a lower annual production rate. This reduced level of 

mining and surface disturbance is expected to continue under this alternative. 

Under Alternative B, Colowyo has already disturbed approximately 789 acres of previously 

undisturbed land over the past 8 years. This accounts for approximately 97.5 percent of the new 

surface disturbance (previously undisturbed land) expected under Alternative B because future 

mining activities under this Alternative are anticipated to occur within areas that have already 

been disturbed with the exception of a small amount of additional surface disturbance 

(approximately 20 acres) that is planned during reclamation operations to allow for the 

topography of disturbed areas to be blended back to the pre-mining state. 

Under Alternative B, it is anticipated that approximately 23.3 million tons of federal coal will be 

extracted, which is about 20 million tons less than the 43 million tons in Alternative A (PR02 as 

Approved in 2007).1

 Based on ongoing geologic and engineering work performed after the 

approval of PR02 in 2007, Colowyo applied for and received a R2P2 modification from BLM in 

2014. This R2P2 modification reflected a determination that approximately 20 million of the 43 

million tons originally approved by BLM for mining was no longer economically recoverable. As 

explained below, it is common for actually-recoverable coal to differ from the originally 

approved tonnage, as additional experience and data is gathered and the geologic model is 

updated. Alternative B also analyzes mining at a maximum rate of 5.0 mtpy from 2008 through 

2014 instead of the 6.0 mtpy under Alternative A, and mining at a maximum rate of 4.0 mtpy 

from 2015 until the end of mining in about 2019. These rates reflect recent production 

experience and are the best estimates of rates that are reasonably foreseeable given the 

remaining reserves. 

Under Alternative B, the life of the Project is projected to be from 2008 through 2019. This 

estimate is based on the actual production rate that has ranged from a high of about 4.95 mtpy 

in 2008 to a low of about 2.1 mtpy in 2012 for the mine as a whole. For the time period from 

2008 to 2014, the South Taylor Pit produced coal at an average rate of 1.47 mtpy, ranging from 

a high of about 1.84 mtpy to a low of about 1.18 mtpy. Production primarily from the 

previously permitted West Pit accounted for the balance of the production from the mine as a 

whole through 2014 when the West Pit operation ceased. The previously permitted Section 16 

Pit also contributed small amounts to the mine production through 2013 when operations in 

that pit ceased. Based on remaining coal reserves and the actual 2014 production rate of 2.48 

mtpy, mining at the South Taylor/Lower Wilson Permit Expansion Area, this alternative 

1 Of this 23.3 million tons of coal, approximately 10 million tons have already been extracted from the South 

Taylor Pit since 2008.

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 2-12

Mining Plan Modification Environmental Assessment

 
Chapter 2 – Proposed Action and Alternatives

projects that mining would be completed in the Project Area in approximately four years, or 

2019.2

 

From 2008 through 2014, the Colowyo coal mine produced a total of 20,446,445 tons of coal 

from all permitted operations (Section 16 Pit, West Pit, and South Taylor Pit) at an average 

production rate of 2.92 mtpy. Between 2008 and 2014, a total of 10,314,641 tons were

produced from just the South Taylor Pit. Under this alternative, mining would continue at the 

2014 production rate of approximately 2.48 mtpy and approximately 13 million tons of 

additional coal is projected to be mined from the South Taylor Pit over approximately the next 

four years. Under this alternative, the total amount of coal already mined and projected to be 

mined from the South Taylor Pit is about 23.3 million tons—a reduction of about 20 million 

tons from that projected under Alternative A. 

Under Alternative B, approximately 13 million tons of recoverable coal remains to be mined in 

the South Taylor/Lower Wilson permit expansion area. Surface mine reserves for the South 

Taylor Pit are calculated using the geologic model. The geologic model is constructed using 

drill data collected during exploratory drilling projects as well as periodic in-pit drilling projects. 

The drilling data is used to develop three-dimensional models of the coal seams that are then 

used to calculate a projected amount of recoverable coal. The projected amount of 

recoverable coal is fully contained within the selected pit shell. Recovery percentages are 

estimated for the target coal seams and a contingency value of 10 percent is projected to 

address seam thicknesses when recoverable tons are estimated.

Under this alternative, the reclamation objective for the South Taylor area is to restore the 

mined area to a land use capability that will be equal to or better than that which previously

existed. Ultimately, the areas being mined will be returned to their original use as rangeland, 

and the watersheds affected by the mined areas will be restored to their approximate premining character. Specifically, Colowyo proposes to reclaim the mined areas to a rangeland 

condition capable of supporting both domestic livestock and wildlife. Reclamation, including 

backfilling and grading, replacement of topsoil, and the re-vegetation of approved flora, has 

already occurred at the mine, and, under this alternative, we expect this to continue in 

accordance with the revised PR02. Of the 789 acres of new disturbance that has already occurred, 

approximately 62 acres have been reclaimed with regrading, topsoil, and reseeding. Colowyo is 

currently self-bonded for $80,517,829 which is the total liability for the existing mining operation and 

which includes the existing East, West, and South Taylor Pits and the supporting infrastructure. 

Colowyo’s self-bond will ensure that reclamation for the Project is completed in accordance with 

the permit, State rules, and SMCRA.

2.3.1 CDRMS Approved Revisions to the Permit 2008 - Present

In 2008, Colowyo began mining at the South Taylor Pit, which has continued to the present. 

However, as described in Section 2.3 above, this mining has conformed to numerous revisions 

approved by CDRMS to PR02 as Approved in 2007. These revisions reflect the fact that mining 

is a dynamic process that requires continual collection, interpretation, and analysis of new 

2 In contrast, under Alternative A, the maximum production rate for the mining operation is expected to increase 

from 4.5 mtpy to up to a maximum of 6.0 mtpy and the for the life of the mine, which would be from 2008-2017.

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 2-13

Mining Plan Modification Environmental Assessment

 
Chapter 2 – Proposed Action and Alternatives

geologic and engineering data as the operation progresses. This process results in constant 

refinement of the geologic and engineering models that are the basis for mine operation 

decisions. The CDRMS coal mine permitting program is authorized under the Colorado 

Surface Coal Mining Reclamation Act of 1979 and has been approved by the Secretary as 

provided for in SMCRA. The program is implemented through the regulations of the Colorado 

Mined Land Reclamation Board for Coal Mining. It provides mine permittees the opportunity 

to submit for review and approval, if appropriate, of a variety of potential revisions of approved 

mining permits, depending on the nature of the proposed revision. 

Those revisions are defined in state regulations as follows: 

“’Minor revision’ means a modification in permit provisions to reflect minor alterations in the 

location of roads or other facilities within the permit area, minor alterations in the timing or 

sequencing of mining or reclamation plans approved in accordance with the requirements of 

these Rules or other minor alterations in surface coal mining and reclamation operations which 

shall not cause a significant alteration in the permittee's reclamation plan.” (CDRMS 1980, 

revised 2005)

‘Technical revision’ means a minor change, including incidental permit boundary revisions, to 

the terms or requirements of a permit issued under these Rules, which change shall not cause a 

significant alteration in the operator's reclamation plan. The term includes, but is not limited 

to, increases in coal production, reduction or termination of approved environmental 

monitoring programs, or design changes for regulated structures or facilities.” (CDRMS 1980, 

revised 2005)

‘Permit revision’ means a significant alteration of the terms or requirements of a permit issued 

under the Rules and the Act, including, but not limited to, significant changes in the reclamation 

plan, and other actions which the Board may by regulation prescribe. ‘Permit revision’ does not 

include a technical revision as defined in 1.04(136).” (CDRMS 1980, revised 2005)

Whenever CDRMS determines that a revision may result in the mining of leased federal coal, 

the State notifies OSMRE. OSMRE then makes a determination as to whether the revision 

triggers preparation of a mining plan or mining plan modification, and proceeds accordingly. 

Under the state coal mine permitting rules, surface mining permits are valid for a term of five years 

with a right of renewal. CDRMS is also required to perform a review of existing permits at the 

permit midterm and, during that review process, it may require revision or modification of 

permit provisions to ensure compliance with the Colorado Surface Coal Mining Reclamation 

Act of 1979 and state rules. In order to ensure compliance with reclamation and other permit 

requirements, CDRMS performs monthly inspections of the Project. In addition, valid existing 

permits have the right of successive renewal at the end of the permit term, with the approval of 

CDRMS. Through the application process for a permit renewal, CDRMS may also require 

revision or modification of permit provisions. (CDRMS 1980, revised 2005) 

Mining in the South Taylor Pit has progressed from 2008 under the revised PR02, and as is 

typical with most Colorado mines, a number of revisions have been approved by CDRMS. A 

total of 45 Minor Revisions, 34 Technical Revisions, 2 renewals, and 1 midterm review of PR02 

have been approved by CDRMS since 2007, some of which have resulted in changes to the 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 2-14

Mining Plan Modification Environmental Assessment
Chapter 2 – Proposed Action and Alternatives

original plan as reflected in the PR02 as Approved in 2007. However, none of these revisions 

required approval of new mining plan modification. The resulting current configuration and existing 

disturbance area of the South Taylor operation is shown in Figure 2-3. Some of the more 

substantial changes to revised PR02 that did not require approval by the ASLM since it was 

originally approved are described below:

• A technical revision moved the locations of the two temporary spoil stockpiles to the 

west. In Alternative A, two temporary spoil stockpiles would be constructed, one on 

top of the East Taylor Fill and the other directly east of the East Taylor Fill within a 

previously reclaimed area called the Section 16 Pit. Under Alternative B, the two 

temporary spoil stockpiles were actually constructed on top of the West Taylor Fill and 

on top of the East Taylor Fill avoiding the reclaimed area and further disturbance of 

approximately 70 acres of re-established vegetation.

• A technical revision reduced the surface disturbance by a total of 450 acres for 

Alternative B by relocating spoil stockpiles to fill areas.

• A technical revision reduced the disturbance footprint of the South Taylor Pit. In 

Alternative A, the South Taylor Pit would be 8,835 feet long by 7,005 feet wide and 580 

feet deep covering approximately 981 acres. In Alternative B, the pit as it is currently 

configured is 4,974 feet long by 4,138 feet wide and 440 feet deep, covering 

approximately 429 acres, a reduction of disturbed acres by about 44 percent when 

compared to Alternative A.

2.3.2 Currently Approved Mine Operation Components 

The Alternative B operation plan includes the following mine components and facilities:

• One open pit, the South Taylor Pit, to access the coal seams, including a highwall 

mining operation; 

• Two permanent and two temporary spoil stockpile areas to store spoil permanently 

and during mining for use in backfilling the open pit during reclamation;

• Dispersed facilities necessary to conduct mining operations including: 

o Temporary light use roads;

o Temporary topsoil stockpile areas to store topsoil removed from disturbed 

areas for use in reclamation;

o A 69 kV power line and associated power poles within the area of mining 

operations to power the dragline and shovel;

o Temporary berms; 

o Waterline and storage tank; and,

o Parking lot, first aid building, and a fuel island.

• Sediment ponds and diversion ditches.

The total acreage proposed to be disturbed for the Project components under Alternative B is 

1,250 acres (Table 2.3-1). PR02 as Revised in 2007 would disturb 809 acres of previously 

undisturbed land and 441 acres of land previously disturbed under PR01, including some land 

under partial or final reclamation. It is not uncommon that a proposed permit expansion 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 2-15

Mining Plan Modification Environmental Assessment
Chapter 2 – Proposed Action and Alternatives

project area would overlap an existing operation and plan to disturb areas that were already 

disturbed and/or in various stages of reclamation. 

Since 2007, 789 acres of previously undisturbed land have now been disturbed by Alternative B 

mining activities. From now until the proposed completion of mining, all mining activities would 

occur within areas that are already disturbed. All facilities supporting the mining operation 

have been constructed. An additional 20 acres would be disturbed during final reclamation 

operations. Upon completion of Alternative B there would be a total new disturbance of 809 

acres that had not previously been disturbed within the permit area. This is 371.7 acres less 

than the 1,180.7 acres of undisturbed land proposed to be disturbed under Alternative A. 

Table 2.3-1 Alternative B Proposed Acreage by Project Component 

Project Component Total Acres Disturbed 

for Each Component

Previously 

Disturbed Acres

Previously 

Undisturbed Acres

South Taylor Pit 429 19 410 

Temporary Spoil Stockpiles 310 136 174

Permanent Spoil Valley Fills 

(East and West Taylor)1

 287 214 73

Sediment Ponds & Ditches 8 0 8

Temporary Topsoil 

Stockpiles 69 62 7 

Other Disturbed Areas 61 6 55

Reclaimed Areas 66 4 62

Future Disturbance 20 0 20

Total Acres 1,250 441 809 1

Includes acreage from an area between the two permanent valley fills disturbed to support mining activities.

2.3.3 Mining Methods and Operation

Since 2008, the mining methods and operation have been the same as those described for 

Alternative A in Section 2.2.2, and are planned to continue in the same manner for the 

remainder of the mine life. 

2.3.4 Project Design Features

As described in Section 2.2.3, the SMCRA permitting process under the State of Colorado’s 

approved regulatory program requires applicants to incorporate design features into their mining 

proposals to protect or minimize impacts to a wide variety of environmental resources. 

Alternative B incorporates the design features included in Alternative A (Table 2.2-1 and

Appendix B), and additional features required as a result of approved minor revisions, 

technical revisions, midterm reviews, and permit renewals since 2008. A summary list of the 

more substantial additional design features incorporated in Alternative B (PR02 as Revised) is 

included in Table 2.3-2 and a more detailed description of the design features incorporated in 

Alternative A is included in Appendix B. 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 2-16

Mining Plan Modification Environmental Assessment
Colorado

13

3N 94W

3N 93W

03 02

07

08 09 10

11

14

15 16

17

18

19

20 21 22

23

26 27

28

29

30

12

13

24

25

51

Moffat

Rio Blanco

SCS

SCS

SCS

SCS

Future Planned

Disturbance

Alternative B

PR02 As Revised

2-3

Colowyo Coal Mine, South Taylor/Lower Wilson

Permit Expansion Area Mining Plan Modification

Environmental Assessment

Notes

1.

2.

0 2,000 4,000

Feet

Project Area

Approved SMCRA Permit Area

Future Planned Disturbance

Actual Disturbance since PR 02

Disturbance not associated with PR 02

Topsoil Stockpile

Sediment Control Structure (SCS)

East Taylor Fill

East Taylor Temporary Fill

Reclaimed Area

West Taylor Fill

South Taylor Pit Shell

County Road

Highway

Section Boundary

Township Boundary

County Boundary

Land Status

Bureau of Land Management

Private

State

1:24,000 (At original document size of 11x17)

Disclaimer: Figure prepared for OSMRE by Stantec. Stantec assumes no responsibility for data supplied in electronic format. The recipient accepts full responsibility for verifying the accuracy and completeness of the data. The recipient releases Stantec, its officers, employees, consultants and agents, from any and all claims arising in any way from the content or provision of the data.

Coordinate System: NAD 1983 UTM Zone 13N

Basemap: Content may not reflect National Geographic's

current map policy. Sources: National Geographic, Esri,

DeLorme, HERE, UNEP-WCMC, USGS, NASA, ESA, METI, NRCAN,

GEBCO, NOAA, increment P Corp.

Project 

Location

Rio Blanco & Moffat Counties

Colorado

Project Location

Project

Figure No.

Title
Chapter 2 – Proposed Action and Alternatives

Table 2.3-2 Summary of Alternative B Additional Design Features

2.4 Alternative C - No Action Alternative

The No Action Alternative, like Alternative B, reflects the surface disturbance and mining operations that 

have already occurred in the South Taylor/Lower Wilson Permit Expansion Area since 2007 as the 

result of subsequent revisions to PR02 approved by CDRMS. Under Alternative C, Colowyo has already 

disturbed approximately 789 acres of previously undisturbed land over the past 8 years. Of the 789 

acres of new disturbance that has already occurred, approximately 62 acres have been reclaimed 

with regrading, topsoil, and reseeding. However, the proposed mining plan modification as 

described under Alternative B above, i.e., to continue mining operations, would not be approved. 

Colowyo would terminate the current mining operation in the South Taylor/Lower Wilson 

Permit Expansion Area in September 2015 following an orderly shutdown and would proceed 

immediately to initiate reclamation of remaining un-reclaimed lands disturbed by the South 

Taylor/Lower Wilson operation since 2007. 

2.5 Alternatives Considered but Eliminated from Further Study

If an alternative is considered during the NEPA process, but the agency decides not to analyze 

the alternative in detail, the agency must identify those alternatives and briefly explain why 

those alternatives were eliminated from detailed study (40 CFR 1502.14). An action alternative 

may be eliminated from detailed study for a number of reasons, including: 

• it is ineffective (does not respond to the purpose and need);

• it is technically or economically infeasible (consider whether implementation of the 

alternative is likely given past and current practice and technology);

• it is inconsistent with the basic policy objectives for the management of the area (such 

as, not in conformance with the land use plan (LUP);

• its implementation is remote or speculative;

• it is substantially similar in design to an alternative that is analyzed; or, 

• it would have substantially similar effects to an alternative that is analyzed.

Resource Area Measure

Fish and Wildlife

Establish sagebrush steppe to benefit Greater sage grouse (comprised of both core and 

ecotonal areas) on approximately 450 acres (minimum of 225 acres core) of the post-2008 

reclamation for the original and South Taylor permit areas, or as otherwise agreed upon 

between Colowyo and CDRMS. 

Threatened and 

Endangered 

Species

Revegetate for Greater sage grouse brooding habitat.

Limit grazing to 60% to 80% of carrying capacity to provide for increased Greater sage 

grouse brood population. 

Livestock Grazing Limit grazing to 60% to 80% of carrying capacity.

Soils

Beginning with 2010 reclamation activities, institute a variable topsoil depth program to 

create distinct ecotonal habitats. Ridgelines and sideslopes received a variable depth to 

mimic natural deposition of soils and target a stable grassland ecotone (i.e. grazing areas). 

Flatter areas receive a constant topsoil depth to encourage sagebrush establishment to 

create sage grouse brood rearing habitat (i.e., sagebrush steppe areas) 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 2-18

Mining Plan Modification Environmental Assessment
Chapter 2 – Proposed Action and Alternatives

2.5.1 Underground Mining Alternative

An alternative to require Colowyo to use underground mining methods to extract the coal was 

identified in public comments received during the outreach period, considered by OSMRE and 

eliminated from detailed study for the following reasons: CDRMS has approved a surface mining

permit for this project using surface mining techniques; and underground mining is inconsistent 

with the approved permit. The Purpose and Need for this EA is predicated upon review of a 

surface mining plan included as part of the approved surface mining permit. An Underground 

Mining Alternative would, thus, be inconsistent with the Purpose and Need for this action. 

Also, federal coal leases COC 29225 and COC 29226 are surface reserve leases only. These 

leases were sold by the federal government, purchased by the mining company, and held by the 

mining company, with the clear understanding by all parties concerned that these leases would 

be mined by surface mining methods only. 

This alternative is also economically infeasible at current permitted production rates, and the 

economics of initiating an underground longwall mining operation in the South Taylor/Lower 

Wilson Expansion Area are not cost effective. The facilities and equipment needed for 

underground mining are different from surface mining. Because the infrastructure for 

underground mining is not in place at the Colowyo Mine, new infrastructure for underground 

mining would need to be constructed. The capital expenditure to develop an underground 

mine would be prohibitive. In addition, all new surface facilities would need to be constructed, 

including, but not limited to, conveyors, coal stock piles, a wash plant, and maintenance and 

support facilities. In addition, all new underground mining equipment would need to be 

purchased such as, but not limited to, a long wall mining system, conveyor 

systems/drives/power stations, vehicles for transporting men and supplies, several continuous 

miners, shuttle cars, large and small ventilation fans, and roof bolters. 

In addition, approval by CDRMS of an application for a Permit Revision would be required to 

authorize underground mining. The process for Colowyo to design and engineer a new 

underground mine and for CDRMS to process a new permit application would take a number 

of years. The timeline for these processes would exceed the projected life of current surface 

mining at the South Taylor Pit and the revenue generation to allow investment in new 

infrastructure at the Colowyo Mine. These factors would also result in this being an 

economically unreasonable alternative to consider.

In summary, this alternative was not brought forward for analysis because underground mining 

does not respond to the Purpose and Need for this action and in addition, the economic 

burden to shift to underground mining would be prohibitive. 

2.5.2 Air Quality Mitigation Alternatives

Some public comments suggested that OSMRE consider alternatives that mitigate air quality 

impacts, specifically by imposing more stringent emission limits at the Craig Generating Station

and by requiring oil and gas operators in the region to reduce their emissions. These proposals 

are not alternatives to the mining operation. OSMRE has determined that, under NEPA, 

activities at the Craig Generating Station and nearby oil and gas operations are not dependent 

on the Proposed Action considered here and therefore do not meet the regulatory definition 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 2-19

Mining Plan Modification Environmental Assessment
Chapter 2 – Proposed Action and Alternatives

of a connected action (40 CFR 1508.25 (a) 1.) relative to any alternative carried forward, and 

do not fall within the scope of the Purpose and Need. However, the effects of coal combustion 

are analyzed in Alternatives A and B, as well as in the No Action Alternative because they are 

considered to be indirect effects. CEQ regulations at 40 CFR 1508 (b) define “indirect effects” 

as those which are caused by the proposed action and are later in time or farther removed in 

distance, but are still reasonably foreseeable. These indirect effects would occur as a result of 

burning the coal that is mined. 

The Colowyo Mine is required to comply with the requirements of the Clean Air Act of 1970, 

as revised, and to obtain approval of an air quality permit from the CDPHE, under the 

requirements of the Colorado Air Pollution Prevention and Control Act that would 

incorporate measures that address the issues raised. Both Alternative A and Alternative B

incorporate an Air Pollution Control Plan approved by CDRMS as part of the surface mining

permit approval that incorporates design features committed to by Colowyo. As such, specific 

air quality mitigation under a separate and specific alternative would have substantially similar 

effects to that analyzed for Alternatives A and B. 

2.5.3 Mining Plan with Reduced Disturbance Alternatives

As described above, PR02 was approved by CDRMS in 2007 and the mining plan modification for 

PR02 was initially approved by the ASLM (Alternative A). As a result of these approvals, mine 

operations were initiated in 2008, and mining has continued over the past seven years, subject to 

CDRMS approved revisions, which reduced the disturbance area (Alternative B). Alternatives that would 

consider a mining plan that is substantively different than what has already occurred between 2007 

and the present would be technically infeasible and not consistent with the Purpose and Need and were 

not carried forward for analysis. We also considered alternatives that would reduce the disturbance 

area; however, we also did not carry these forward for analysis because those alternatives would be 

substantially similar in design and have substantially similar effects to Alternative B. 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 2-20

Mining Plan Modification Environmental Assessment
Chapter 3 – Affected Environment

CHAPTER 3 AFFECTED ENVIRONMENT

3.1 GENERAL SETTING

The CEQ regulations state that NEPA documents “must concentrate on the issues that are truly 

significant to the action in question, rather than amassing needless detail” (40 CFR 1500.1(b)). While 

many issues may arise during scoping, not all of the issues raised warrant analysis in an EA. Issues will 

be analyzed if: 1) an analysis of the issue is necessary to make a reasoned choice between alternatives, 

or 2) if the issue is associated with a significant direct, indirect, or cumulative impacts, or where analysis 

is necessary to determine the significance of the impacts. Table 3.1-1 lists the resources considered 

and the determination as to whether they require additional analysis.

Table 3.1-1 Resources and Determination of Need for Further Analysis

Determination1 Resource Rationale for Determination

PI Topography See discussion below.

PI Air Quality See discussion below.

PI Greenhouse Gases See discussion below.

PI Geology and 

Minerals See discussion below.

PI Surface and 

Ground Water See discussion below.

PI

Vegetation (includes 

invasive species and 

upland vegetation)

See discussion below.

PI Wetlands and 

Riparian Zones See discussion below.

PI Fish and Wildlife 

Resources See discussion below.

PI

Special Status 

Species (includes 

animal and plant 

species)

See discussion below.

PI Cultural and 

Historic Resources See discussion below.

PI Indian Concerns See discussion below.

PI Socioeconomics See discussion below.

PI Environmental 

Justice See discussion below.

PI Visual Resources See discussion below.

PI Recreation See discussion below.

PI Paleontology See discussion below.

PI Access and See discussion below.

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 3-1

Mining Plan Modification Environmental Assessment
Chapter 3 – Affected Environment

Determination1 Resource Rationale for Determination

Transportation

Solid or Hazardous PI See discussion below. Waste

PI Noise See discussion below.

PI Livestock Grazing See discussion below.

PI Soils Resources See discussion below.

NP Prime Farmlands See discussion below.

NP Alluvial Valley Floors See discussion below.

PI Public Involvement See discussion in Chapter 6.

No Herd Management Areas are located within or near the NP Wild Horses Project Area.

No FEMA- designated floodplains are located within the Project NP Floodplains Area.

Wildfire NI There would be no impact to fire management. Management

Forest No portion of the Project Area is managed for commercial timber NP Management operations. 

Areas of Critical No designated Areas of Critical Environmental Concern are located NP Environmental 

within or near the Project Area. Concern

Wild and Scenic No Wild and Scenic Rivers are located within or near the Project NP Rivers Area.

All alternatives would have no impact to existing realty Realty NI authorizations. There are no proposed changes to land tenure in Authorizations

the Project Area.

As the permit area is closed to the general public, no special use Special Use NP authorizations are available in the Project Area. Therefore, this will Authorization

not be discussed further.

Inventoried There are no inventoried roadless areas located within or near the NP Roadless Areas Project Area.

There are no Wilderness Study Areas or lands that meet the 

NP Wilderness Areas criteria for wilderness characteristics located within or near the 

Project Area.

NP Scenic Byways There are no scenic byways located within or near the Project Area. 1 NP = Not present in the Project Area. NI = Present, but not affected to a degree that detailed analysis is required. 

PI = Present with the potential for impact analyzed in this EA.

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 3-2 

Mining Plan Modification Environmental Assessment
Chapter 3 – Affected Environment

The Project Area is located approximately 22 miles (35.4 km) north of Meeker, Colorado in 

Moffat and Rio Blanco counties (Figure 1-1). Nearby Moffat and Rio Blanco County 

communities include Maybell, Hamilton, Craig, and Meeker. 

The climate is semi-arid shrub steppe with a mean annual precipitation of approximately 14 to 

16 inches per year. The growing season is approximately 90 days. Prevailing winds are 

westerly. Vegetative communities in this landscape include sagebrush-perennial grass, and other

shrub/woodland types such as oak brush, snowberry (Symphoricarpos albus), serviceberry 

(Amelanchier sp.), mountain mahogany (Cercocarpus ledifolius), pinyon-juniper, and aspen (Populus 

tremuloides). Vegetation cover ranges between 35 and 75 percent. Scattered aspen groves 

grow at the higher elevations and scattered juniper trees occur in the Project Area. Riparian 

vegetation occurs along the fringes of both Good Spring and Taylor Creeks and their tributaries 

(OSMRE 2001).

Figure 2-1 depicts the Affected Environment for the entire Project Area, which includes the 

entire South Taylor/Lower Wilson Permit Expansion, and is the area included in the analysis for 

each resource in this chapter. We note, however, that the actual disturbance area for the 

Project has been smaller than the Project Area. The actual and reasonably foreseeable future 

disturbance of the Project is shown on Figures 2-3 (Alternative B) and 2-2 (Alternative A),

respectively.

3.2 TOPOGRAPHY

The Project Area is located on the southern edge of the Yampa River Basin north of the 

Danforth Hills. The elevation ranges from approximately 8,660 feet above mean sea level 

(amsl) on the southern end of the Project Area to 6,620 feet on the north end. The area 

consists of gently sloping interfluvial ridges divided by deeply entrenched gulches and drainage 

valleys. Good Spring Creek to the east and Taylor Creek and Wilson Creek to the west are 

perennial streams. All of these drainages flow northeasterly to Milk Creek, a tributary of the 

Yampa River. Valley bottoms are generally narrow with very steep sides. Valley and gulch 

slopes are frequently 30 to 60 percent grade or steeper, but ridgetops are wide and gently 

sloping. The pre-mining topography is presented on Figure 18A in the approved PR02 (CDRMS 

2007).

3.3 AIR AND CLIMATE RESOURCES

3.3.1 Airshed for Analysis

The regional airshed (approximately 4,000 square miles [12,360 km2]) was defined using a 

topographic/airshed approach. An assessment was conducted to determine the reasonable 

airshed where regional impacts could occur. Boundaries were defined by topographic features. 

Meeker represents the southwest corner of the airshed. Heading northwest along Route 64, 

the western edge is defined by Sagebrush Draw, Elk Spring Ridge, and Cross Mountain. The 

northwest corner runs through Ninemile Basin just northwest of Godiva Rim. The boundary 

follows the Little Snake River northeast until approximately Shaffer’s Draw. The northern 

boundary extends east across the Great Divide ridge, past State Highway 13 and the Elkhead 

Mountains. Sand Mountain represents the northeast corner of the air boundary and heads 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 3-3

Mining Plan Modification Environmental Assessment
Chapter 3 – Affected Environment

southeast to the town of Clark. The eastern edge is Steamboat Springs. The southeastern 

edge heads south through the town of Yampa and into Garfield County. Big Ridge and Oak 

Ridge, and back to Meeker, encompasses the southern boundary (Figure 3-1).

3.3.2 Regional Climate 

The climate of the area is typical of a semi-arid, continental, mid-latitude region: warm summers 

and cold winters are characterized by high diurnal and seasonal temperature variations. The 

flow of Pacific air dominating the climate descends into the area as a warming and drying mass 

after depositing most of its moisture over the western slopes of the Sierra Nevada and Cascade 

Mountains. This generally creates a large rain shadow effect over Nevada, Utah, and western 

Colorado. Typically, severe storms and low pressure systems bypass the region by deflecting 

north or south over lower elevations of the Rocky Mountains in Wyoming and New Mexico. 

The predominant air mass over the Rocky Mountains during the winter is usually continental 

polar and produces cold, dry air during storm-free periods. High pressure systems that result 

in fine, light, powdery snow tend to become established in winter over the region which lies 

within the mean winter storm track. During the summer months, the air masses are generally 

maritime polar. This region is usually south of the main storm track in the summer; however, 

localized thundershowers do occur primarily during the afternoon, if a moisture supply is 

available either locally or in the air mass (BLM 2006).

3.3.3 Local Climate and Meteorology

Two onsite meteorological towers exist at the mine (Figure 3-2). The North Site was 

installed in 1997 and was brought back into service in 2008. The Gossard Site was installed in 

2011. The North Site is approximately 3 miles (5 km) northeast of the center of the South 

Taylor Pit, at an elevation of 7,395 feet amsl, and the Gossard Site is located near the mine’s rail 

load-out approximately 6 miles (10 km) north of the center of the South Taylor Pit at an 

elevation of 6,325 feet amsl. Each site collects data for temperature, relative humidity, wind 

speed and direction, barometric pressure and solar radiation. Data from these sites is provided 

to the CDPHE on a quarterly basis. Data for each site was reviewed from installation through 

the end of 2013 (Appendix C). The onsite data was also reviewed in the context of other 

regional meteorological monitoring sites at Craig and Meeker to develop a climatological

summary of the region. 

The data from Craig was collected at the Craig Airport (Station ID 24046). The station is 

located at 40.4930°, -107.5239° at approximately 6,191 feet amsl. The site records 

temperature, barometric pressure, relative humidity, precipitation, and wind speed and 

direction. The National Climate Data Center (NCDC) provides data for this site from 

September of 1996 through the present and the University of Utah’s Mesowest provides data 

for this site since January of 1997 though the present (Appendix C).

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 3-4

Mining Plan Modification Environmental Assessment
Colorado

"d "d

Eagle

Garfield

Eagle

Routt

Garfield

Rio Blanco

Garfield

Routt

Moffat

Rio Blanco

Moffat

Routt

Rio Blanco

Routt

Craig

Generating

Station

Hayden

Generating

Station

Air Quality Region

3-1

Colowyo Coal Mine, South Taylor/Lower Wilson

Permit Expansion Area Mining Plan Modification

Environmental Assessment

Notes

1.

2.

0 8 16

miles

Project Area

Air Quality Analysis Area

Regional Airshed Boundary

"d Generating Station

County Boundary

($$ ̄

1:506,880 (At original document size of 11x17)

Disclaimer: Figure prepared for OSMRE by Stantec. Stantec assumes no responsibility for data supplied in electronic format. The recipient accepts full responsibility for verifying the accuracy and completeness of the data. The recipient releases Stantec, its officers, employees, consultants and agents, from any and all claims arising in any way from the content or provision of the data.

Coordinate System: NAD 1983 UTM Zone 13N

Basemap: Content may not reflect National Geographic's

current map policy. Sources: National Geographic, Esri,

DeLorme, HERE, UNEP-WCMC, USGS, NASA, ESA, METI, NRCAN,

GEBCO, NOAA, increment P Corp.

Project 

Location

Rio Blanco & Moffat Counties

Colorado

Project Location

Project

Figure No.

Title
Colorado

!(

!(

UV13

SCS

SCS

SCS

SCS

UV180

UV51

UV32

UV17

UV9

Moffat

Rio Blanco

Future Planned

Disturbance

North

(On-site)

Gossard

(On-site)

Onsite Meteorological Monitoring

3-2

Colowyo Coal Mine, South Taylor/Lower Wilson

Permit Expansion Area Mining Plan Modification

Environmental Assessment

($$ ̄

0 4,000 8,000

Feet

1:48,000 (At Original document size of 11x17)

!( Air Quality Monitoring Site

Project Area

Approved SMCRA Permit Area

Future Planned Disturbance

Actual Disturbance since PR 02

Sediment Control Structure

(SCS)

County Road

Highway

County Boundary

Project 

Location

Notes

1: Coordinate System: NAD 1983 UTM Zone 13N

2: Service Layer Credits: Copyright:© 2013 National Geographic

Society, i-cubed

Disclaimer: Figure prepared for OSMRE by Stantec. Stantec assumes no

responsibility for data supplied in electronic format. The recipient

accepts full responsibility for verifying the accuracy and completeness

of the data. The recipient releases Stantec, its officers, employees,

consultants and agents, from any and all claims arising in any way from

the content or provision of the data.

Project

Figure No.

Title

Rio Blanco & Moffat Counties

Colorado

Project Location
Chapter 3 – Affected Environment

The data from Meeker was collected at the Meeker Airport (Station ID 28801). The station is 

located at 40.0444° -107.8883° at approximately 6,365 amsl. The site records temperature, 

barometric pressure, relative humidity, precipitation and wind speed and direction. The NCDC 

provides data for this site from June 1, 1997 through the present and the University of Utah’s 

Mesowest provides data for this site from April 1997 through the present (Appendix C).

The highest mean monthly temperatures occur in July, and range from 66.9 degrees Fahrenheit 

(°F) to 69.2 °F. The lowest mean monthly temperatures occur in January and range from 9.4 °F 

to 20.3 °F. Regional winds are affected by both synoptic events and orographic influences that 

cause wind patterns to predominately flow from southwest to northeast. Wind patterns atop 

the mountain ranges exhibit a stronger west to east flow pattern, while locally in the Project 

Area wind patterns are predominately from the west-southwest direction. The local 

topography also influences wind patterns; the Project Area terrain generally descends from 

south to north with some micro-scale terrain channeling of wind. The northern end of the 

Project Area runs along an east west axis to the south of the Yampa River Valley and the south 

end of the Project Area is characterized by higher mountainous terrain, with more complex 

topographic features. Wind speeds are generally more moderate in the daylight hours and 

lighter in the evening and night time hours. The mean monthly wind speeds ranged from 1.45 

to 5.0m/s. Mean monthly wind speeds are generally lowest in January and highest during the 

four month period of March through June. 

Regional precipitation averages approximately 1.25 inches per month with the highest monthly 

precipitation totals occurring during the spring and fall. Annual precipitation amounts averaged 

from 2005 to 2013 were 13.8 inches in Craig and 16.2 inches in Meeker.

3.3.4 Regulatory Requirements 

The regulatory framework for air quality includes both federal and state rules, regulations, and 

standards promulgated by the EPA and implemented by the CDPHE. The Clean Air Act (CAA)

established the NAAQS for seven criteria pollutants. The criteria pollutants include carbon 

monoxide (CO), lead, nitrogen dioxide (NO2), ozone, particulate matter 10 microns (PM10) or 

less in diameter, particulate matter 2.5 microns (PM2.5) or less in diameter, and sulfur dioxide 

(SO2) (Table 3.3-1). 

Pursuant to the CAA, the EPA has developed classifications for distinct geographical regions 

known as Air Quality Control Regions (AQCR). In Colorado, the state has been divided into 

eight multi-county areas that are generally based on topography and have similar airshed 

characteristics. The Project Area airshed analysis area (Section 3.3.1) lies in the Western 

Slope Air Pollution Control Region as designated by the State of Colorado. The EPA 

designates whole or partial counties as Attainment, Non-Attainment, or Maintenance for each 

criteria air pollutant. Regions classified as in Attainment, are areas in which the pollutant has 

not exceeded the NAAQS. A Non-Attainment classification represents an area in which the 

pollutant has exceeded the NAAQS. The Maintenance designation is used when monitored 

pollutants have been reduced from the Non-Attainment to the Attainment levels. Moffat 

County has been designated as Attainment for all criteria pollutants based on monitoring 

results that were below the applicable NAAQS.

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 3-7

Mining Plan Modification Environmental Assessment
Chapter 3 – Affected Environment

Table 3.3-1 National Ambient Air Quality Standards

Pollutant Averaging 

Time

National 

Standard Form

Carbon Monoxide (CO) 8-hour 9 ppm Not to be exceeded more than once a year

1-hour 35ppm

Lead Rolling 3 month 

average

0.15 μg/m3 Not to be exceeded

Nitrogen Dioxide (NO2) 1-hour 100 ppb 98th percentile, averaged over 3 years

Annual 53 ppb Annual Mean

Ozone 8-hour 0.075 ppm Annual fourth-highest daily maximum 8-hr 

concentration, averaged over 3 years

Particle Pollution PM2.5 Annual 12 μg/m3 Annual mean, averaged over 3 years

24-hour 35 μg/m3 98th percentile, averaged over 3 years

PM10 24-hour 150 μg/m3 Not to be exceeded more than once per year 

on average over 3 years

Sulfur Dioxide (SO2) 1-hour 75 ppb 99th percentile of 1-hour daily maximum 

concentrations, averaged over 3 years

3-hour 0.5 ppm Not to be exceeded more than once per year

3-hour 700 μg/m3 Not to be exceeded more than once in any 

twelve month period

Source: http://www.epa.gov/air/criteria.html as of October, 2011

μg/m3 = micrograms per cubic meter of air

ppm = parts per million, ppb = parts per billion

State standard established by the Colorado Air Quality Control Commission

The CAA also divides areas where air quality is already cleaner than required by federal 

standards into three classes, and specifies the increments of SO2, NO2 and particulate pollution 

allowed in each class as regulated by the Prevention of Significant Deterioration (PSD) 

regulations (40 CFR 52.21). Class I areas include international and national parks, wilderness 

and other pristine areas; allowable increments of new pollution in these areas are very small. 

Class II areas include all attainment and not classifiable areas, which are not designated as Class 

I; allowable increments of new pollution in these areas are modest. Class III represents 

selected areas that states may designate for development; allowable increments of new 

pollution are large (but not exceeding NAAQS); no Class III areas are designated in Colorado. 

All areas not designated as Class I are initially designated as Class II areas. The Project Area is 

located in a Class II area as codified in the Colorado State PSD permitting rules1

. The PSD 

regulations are applicable to a source pollutant if the source has the potential to exceed the 

major source thresholds, of either 100 or 250 tons per year (tpy) of a regulated New Source 

Review pollutant, depending on the type of source pollutant that it is. For stationary source 

categories listed in the regulation, the threshold is 100 tpy. For source categories that are not 

listed, such as surface mining operations, the threshold is 250 tpy. The potential to emit 

calculation does not include fugitive emissions for the purpose of determining if the facility 

exceeds the 250 tpy threshold. Fugitive emissions are defined by EPA as, “those emissions that 

could not reasonably pass through a stack, chimney, vent, or other functionally-equivalent 

opening”. The Project is classified under the CAA as a minor source of air quality emissions 

1 5 CCR 1001-05, Regulation Number 3, Part D, Concerning Major Stationary Source New Source Review and 

Prevention of Significant Deterioration

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 3-8

Mining Plan Modification Environmental Assessment

 
Chapter 3 – Affected Environment

and would not exceed these thresholds under the PSD regulations because the majority of the 

project emissions sources are fugitive in nature and as such are not included in the 

determination of PSD applicability for a non-listed source category such as coal mining. 

Therefore, PSD regulations and preconstruction monitoring would not be applicable to the 

mine. It should be noted that minor sources while not subject to PSD regulations can affect 

increments, but emissions remain below increment thresholds. 

Stationary sources in the vicinity of the Project Area that are regulated under PSD include the 

Craig Generating Station and the Hayden Generating Station outside of Craig and Hayden, 

Colorado respectively. 

Federal PSD regulations limit the maximum allowable increase in ambient pollutant 

concentration in Class I, Class II, and Class III areas (Table 3.3-2). The nearest Class I areas to 

the Project Area are the Flat Top Wilderness, 22 miles (35 km) southeast; Mount Zirkel 

Wilderness, 50 miles (80 km) northeast; and the Maroon Bells-Snowmass Wilderness and 

Eagle's Nest Wilderness, 62 miles(100 km) south/southeast and southeast, respectively

(Figure 3-3). It should also be noted that Class II areas such as Dinosaur National Monument 

and Colorado National Monument are treated as Class I areas with regard to SO2

concentrations.

Table 3.3-2 Federal Prevention of Significant Deterioration Limits

Maximum Allowable Increase (μg/m3)

Pollutant Averaging Time Class I Area Class II Area Class III Area

PM2.5 Annual 1 4 8

24-hour 2 9 18

PM10 Annual 4 17 34

24-hour 8 30 60

SO2 Annual 2 20 40

24-hour 5 91 182

3-hour 25 512 700

NO2 Annual 2.5 25 50

μg/m3 = Micrograms Per Cubic Meter of Air

The CAA also enacted the New Source Performance Standards (NSPS) and National Emissions 

Standards for Hazardous Air Pollutants (NESHAP) for specific types of equipment located at 

new or modified stationary pollutant sources. NSPS regulations limit emissions from source 

categories to minimize the deterioration of air quality. Stationary sources are required to meet 

these limits by installing newer equipment or adding pollution controls to older equipment that 

reduce emissions below the specified limit. The Project Area would include equipment that is 

subject to various NSPS and NESHAP regulations. NSPS and NESHAP standards also apply to 

the locations of final coal combustion. 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 3-9

Mining Plan Modification Environmental Assessment
Chapter 3 – Affected Environment

The CAA Amendments of 1990 introduced a new facility-wide Federal Operating Permit 

program. Federal Operating Permits, also known as Title V permits, are required for facilities 

with the potential to emit more than 100 tpy of a regulated pollutant, 10 tpy of any single 

hazardous air pollutant (HAP), or 25 tpy of any combination of HAPs and considered to be 

major sources of air quality emissions. No NAAQS exist for HAPs; instead emissions of these 

pollutants are regulated by a variety of laws (e.g., NESHAPs) that target the specific source class 

and industrial sectors for stationary, mobile, and product use/formulations. However, Title V 

permitting is still required if HAP emissions rise above the defined thresholds.

The mine’s potential to emit is below the requirements to obtain a Federal Operating Permit 

and, therefore, it would not be subject to Title V permitting. Title V operating permit 

requirements are typically applicable for the locations of final coal combustion. Both the Craig 

and Hayden Generating Stations have Title V permit applicability.

In addition to the permitting of criteria and HAPs regulations exist for the control of mercury 

and air toxics, acid deposition, visibility impacts, and regional haze. 

The final location of coal combustion is often regulated under numerous environmental 

regulations. Until 2011, the Craig Generating Station and other generating facilities had no 

federal standards that required them to limit their emissions of toxic air pollutants like 

mercury, arsenic and metals. On December 16, 2011, the EPA finalized the first national 

standards to reduce mercury and other toxic air pollution from coal and oil-fired power plants. 

These rules set technology-based emissions limitation standards for mercury and other toxic air 

pollutants, reflecting levels achieved by the best-performing sources currently in operation. 

The final rule sets standards for all HAPs emitted by coal- and oil-fired electric generating units 

(EGUs) with a capacity of 25 megawatts or greater. All regulated EGUs are considered major 

under the final rule. EPA did not identify any size, design, or engineering distinction between 

major and area sources. Existing sources generally have up to four years if they need it to 

comply with the Mercury and Air Toxics Standards (MATS)

2

. 

The emissions limits associated with the MATS rule are presented in Table 3.3-3. The Craig 

Generating Station has attained compliance with MATS for Units 1 and 2 at the facility and Unit 

3 will attain compliance by the end of 2015. The Hayden Generating Station complies with a 

more stringent Colorado state-only regulation (Colorado Regulation No. 6, Part B, Section 

VIII.B.10) where each unit is considered a Low Emitter, emitting no more than 29 lb of mercury 

per year.

2 The Supreme Court recently held that the EPA did not properly consider the costs of the MATS rule. See 

Michigan v. EPA, ___ U.S. ___, 192 L. Ed. 2d 674 (June 29, 2015). The consequences of this decision are still 

being assessed by EPA and the lower courts. For purposes of this EA, the analysis includes the MATS rule in effect 

because the primary emitters have already complied with those standards.

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 3-10

Mining Plan Modification Environmental Assessment

 
Colorado

Mount

Zirkel

Wilderness

Maroon

Bells-Snowmass

Wilderness

Flat Tops

Wilderness

Colorado

Utah

Colorado

Wyoming

Class I Areas

3-3

Colowyo Coal Mine, South Taylor/Lower Wilson

Permit Expansion Area Mining Plan Modification

Environmental Assessment

($$ ̄

0 14 28

Miles

1:887,040 (At Original document size of 11x17)

Project Area

Project Area 100-km Buffer

Approved SMCRA Permit Area

USFS Class I Area

State Boundary

Project 

Location

Notes

1: Coordinate System: NAD 1983 UTM Zone 13N

2: Service Layer Credits: Content may not reflect National

Geographic's current map policy. Sources: National

Geographic, Esri, DeLorme, HERE, UNEP-WCMC, USGS, NASA,

ESA, METI, NRCAN, GEBCO, NOAA, increment P Corp.

Disclaimer: Figure prepared for OSMRE by Stantec. Stantec assumes no

responsibility for data supplied in electronic format. The recipient

accepts full responsibility for verifying the accuracy and completeness

of the data. The recipient releases Stantec, its officers, employees,

consultants and agents, from any and all claims arising in any way from

the content or provision of the data.

Project

Figure No.

Title

Rio Blanco & Moffat Counties

Colorado

Project Location
Chapter 3 – Affected Environment

Table 3.3-3 MATS Emission Requirements 

Coal and Oil Fired Units

Subcategory

Mercury Emission Limit

(lb./GWh)

Regular Coal 0.013

Designed for Low Rank Coal

1 0.12 or 0.040

Existing IGCC (Gasified Coal) 0.03

Solid-oil Derived & Continental Liquid Oil 0.002

Non-continental Liquid Oil 0.004

Regular Coal 0.0002

Designed for Low Rank Coal 0.04

New IGCC (Gasified Coal) 0.003

Solid-oil Derived 0.002

Continental Liquid Oil 0.0001

Non-continental Liquid Oil 0.0004

Source: EPA MATS final rule, pp. 347-351, http://www.epa.gov/mats/pdfs/20111216MATSfinal.pdf

lb./GWh = pounds of pollutant per gigawatt – electric output 1 Most of these units burn lignite coal

The PSD regulations described previously also regulate the degradation of Air Quality Related 

Values (AQRV) in Class I areas. The authority to protect AQRVs in federally mandated Class I 

areas is to be done as part of the preconstruction permitting process of major sources. 

AQRVs include all resources sensitive to changes in air quality and typically include visibility 

degradation, pollutant deposition on vegetation and water bodies, and acidification of sensitive 

water bodies. AQRV impact review during permitting is applicable to both the Craig and 

Hayden Generating Stations.

In addition to PSD AQRV analyses, visibility impacts are also included under a State 

Implementation Plan (SIP) for the reduction of Regional Haze. This regulation is used to reduce 

the visibility impacts from existing facilities and introduce additional emissions controls to a 

standard known as Best Available Retrofit Technology (BART). 

The Craig Generating Station has three units that are BART eligible. Units 1 and 2 are included 

in the current Regional Haze SIP. As a result, both are required to include Selective Catalytic 

Reduction (SCR) to control NOx emissions. They are also required to have a wet lime 

scrubber for SO2 control. According to modeling prepared as part of the BART analysis, NOx

controls will improve visibility by 1.01 deciview (dv; a unit of visibility impairment) for Unit 1 

and 0.98 dv for Unit 2. Unit 3 is considered to be eligible for “Reasonable Progress”3. The 

Colorado SIP includes a determination for Unit 3 stating that it is reasonable to include a 

Selective Non-Catalytic Reduction (SNCR) for NOx, which will improve visibility by 0.32 dv. 

3 CDPHE Regional Haze SIP Craig Station https://www.colorado.gov/pacific/sites/default/files/AP_PO_Craig-PowerPlant_0.pdf

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 3-12

Mining Plan Modification Environmental Assessment

 
Chapter 3 – Affected Environment

Similarly, the Hayden Generating Station has two units identified as BART eligible in the SIP. 

Both are using lime spray dryers to control SO2. Unit 1 improves visibility by 0.10 dv and Unit 

2 by 0.21 dv. Hayden also controls NOx using SCR. Visibility improvements are estimated at 

1.12 dv and 0.85 dv for Units 1 and 2, respectively.

The controls being implemented by the two power stations are helping to greatly improve the 

visibility in the region surrounding the Mount Zirkel Wilderness. In addition, the U.S. Forest 

Service has stated that their concerns regarding visibility (originally noted in a letter to the State 

in 1993) within the wilderness have been resolved. The State of Colorado is also in agreement 

that control measures taken by the two facilities are sufficient in resolving the U.S. Forest 

Service concerns. 

3.3.5 Regional Air Quality

The Project Area and vicinity is currently in Attainment or unclassified for all criteria pollutants. 

Monitoring of criteria pollutants in the region is located near population centers or areas of 

specific interest. In the late 1990s the EPA allowed monitoring to cease where pollutants were 

less than 60 percent of the NAAQS, and as a result the data collected for this analysis is 

regionally representative but often monitored at some distance from the Project.

PM10 data from two monitoring locations, one in Steamboat Springs, 74 miles (119 km) eastnortheast of the Project Area, and one in Parachute, 87 miles (140 km) south of the Project 

Area, were reviewed for 2014 (Figure 3-4). Data from 2014 are also available for Rifle and 

Grand Junction. The highest 24-hr concentration for Parachute was 39 micrograms per cubic 

meter of air (μg/m3) and the highest 24-hr concentration for Steamboat was 84 μg/m3. Both 

values were below the NAAQS (150 μg/m3

) (Table 3.3-4).

3.3.5.1 NO2

The nearest representative NO2 data is collected at the USDA Upper Colorado Environmental 

Plant Center in Meeker, 16 miles (25 km) south of the Project Area. The highest hourly 

background at the site during 2014 was 6.1 parts per billion (ppb) which is below the NAAQS 

(100 ppb).

3.3.5.2 PM2.5

The nearest representative PM2.5 data is collected in Rangely, 53 miles (85 km) west of the 

Project Area. The highest 24-hr concentration background at the site during 2014 was 

17.8μg/m3 which is below the NAAQS (35 μg/m3

). 

3.3.5.3 Ozone 

The nearest representative ozone data is collected at Lay Peak (27 km northwest of the Project 

Area). The highest 8-hr background at the site during 2014 was 0.067 parts per million (ppm)

which is below the NAAQS (0.075 ppm).

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 3-13

Mining Plan Modification Environmental Assessment
Colorado

!(

!(

!(

!(

!(

!(

!(

!(

Colorado

Wyoming

Parachute

High School

Steamboat

Meeker

Rocky Mountain

National

Park (RMNP)

Rangely

Lay Peak

North (On-site)

Gossard

(On-site)

Regional Air Quality

Monitoring

3-4

Colowyo Coal Mine, South Taylor/Lower Wilson

Permit Expansion Area Mining Plan Modification

Environmental Assessment

($$ ̄

0 14 28

Miles

1:960,324 (At Original document size of 11x17)

!( Air Quality Monitoring Site

Project Area

Approved SMCRA Permit Area

State Boundary

Project 

Location

Notes

1: Coordinate System: NAD 1983 UTM Zone 13N

2: Service Layer Credits: Content may not reflect National

Geographic's current map policy. Sources: National

Geographic, Esri, DeLorme, HERE, UNEP-WCMC, USGS, NASA,

ESA, METI, NRCAN, GEBCO, NOAA, increment P Corp.

Disclaimer: Figure prepared for OSMRE by Stantec. Stantec assumes no

responsibility for data supplied in electronic format. The recipient

accepts full responsibility for verifying the accuracy and completeness

of the data. The recipient releases Stantec, its officers, employees,

consultants and agents, from any and all claims arising in any way from

the content or provision of the data.

Project

Figure No.

Title

Rio Blanco & Moffat Counties

Colorado

Project Location
Chapter 3 – Affected Environment

Table 3.3-4 Regional Air Quality Monitoring Conditions

Monitor Location Active 

Since

Monitoring 

Agency

Annual 

Samples Elevation (ft.) 1-hr 3-hr 8-hr 24-hr

PM10 (μg/m3)

Rifle 51 mi (82 km) south in 

Rifle, CO 2005 CDPHE 120 47

Grand Junction

93 mi (148 km)

southwest in Grand 

Junction , CO

2004 CDPHE 118 46

Parachute High School

88 mi (140 km)

southwest in Parachute, 

CO

2001 CDPHE 119 5,100 39

Steamboat

56 mi (89 km)

northeast in Steamboat, 

CO

1987 CDPHE 346 7,400 84

Colowyo Onsite Colowyo Existing 

Facility

Detailed discussion in Section 

3.3.7“On-site Air Quality” 7,100 Detailed discussion in Section 3.3.7“On-site Air Quality” 

NO2 (ppb)

Rangely

51 mi (82 km)

southwest near Rangely, 

CO

2011 National Park 

Service 8592 19.6

Meeker 18 mi (28 km) south in 

Meeker, CO 2011 National Park 

Service 8584 6,500 6.1

SO2 (ppb)

Walden - Colorado, 

Chandler Ranch

91 mi (145 km)

northeast, north of the 

Project Area

2012 National Park 

Service 4452 7,930 1 0.5

CO (ppm)

Walden - Colorado, 

Chandler Ranch

91 mi (145 km)

northeast, north of the 

Project Area 

2013 National Park 

Service 4330 7,930 0.3 0.3

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 3-15

Mining Plan Modification Environmental Assessment
Chapter 3 – Affected Environment

Monitor Location Active 

Since

Monitoring 

Agency

Annual 

Samples

Elevation 

(ft.) 1-hr 3-hr 8-hr 24-hr

PM2.5 (μg/m3)

Grand Junction

93 mi (148 km)

southwest in Grand 

Junction, CO

2003 CDPHE 363 29.3

Rangely 51 mi (82 km) west in 

Rangely, CO 2011 National Park Service 325 5,500 17.8

Ozone (ppm)

Rifle 51 mi (82 km) south 

near Rifle, CO 2009 CDPHE

192 days out 

of 214 

required

0.062

Palisade

83 mi (132 km)

southwest near 

Palisade, CO

2009 CDPHE

212 days out 

of 214 

required

0.064

Meeker

17 mi (27 km)

southwest in Meeker, 

CO

2010 National Park 

Service

206 days out 

of 214 

required

0.063

Rangely

51 mi (82 km)

southwest near Rangely, 

CO

2011 National Park 

Service

203 days out 

of 214 

required

0.066

Lay Peak

17 mi (27 km)

northwest, west of 

Craig, CO

2012 CDPHE 6516 6,250 0.067

μg/m3 = micrograms per cubic meter of air; ppm = parts per million; ppb = parts per billion

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 3-16

Mining Plan Modification Environmental Assessment
Chapter 3 – Affected Environment

3.3.5.4 SO2 and CO

The Williams Willow Creek station, which monitors both SO2 and CO, is within 38 miles (61

km) of the Project Area. SO2 and CO measured concentrations of 1.0 ppb in 2012 for all 

averaging periods of interest. Both SO2 and CO are highly affected by local sources of 

combustion and are typically low in the rural Project Area. For similar mining projects in the 

western U.S.

4

, backgrounds of zero have been used when no monitoring data exists. The 

nearest rural monitoring station for SO2 and CO exists at the Chandler Ranch in Walden, 

Colorado, 90 miles (145 km) from the Project Area. For 2014, the highest SO2 1-hr, 3-hr and 

24-hr backgrounds at the site were 1.0, 0.5 and 0.3 ppb, respectively. The highest 1-hr and 8-hr 

CO backgrounds were 0.25 and 0.3 ppb, respectively. Both SO2 and CO are below the 

NAAQS. 

3.3.6 Hazardous Air Pollutants

HAPs are those pollutants that are known or suspected to cause cancer or other serious health 

effects, such as reproductive effects or birth defects, or adverse environmental effects. The 

majority of HAPs originate from stationary sources (e.g., factories, refineries, power plants) and 

mobile sources (e.g., cars, trucks, buses), as well as indoor sources (building materials and 

cleaning solvents). The majority of HAPs emitted from the Project would be the result of 

vehicle use. The major source threshold for HAPs is 10 tpy of any one HAP or 25 tpy of 

aggregate HAPs. The Colowyo Mine would not be categorized as a major source for HAPs

because the mine produces approximately 2 tpy of total HAPs. 

3.3.7 Onsite Air Quality

The North and Gossard air monitoring stations are equipped with Rupprecht & Patashnick 

Model 1400a continuous PM10 samplers and R.M. Young AQ Model 05305 prop-vane 

anemometers. The station locations were selected with direction and approval from the 

Colorado Air Pollution Control Division (APCD), and were designed to monitor the maximum 

PM10 impacts at the Colowyo Mine property line. The monitoring stations are operated 

according to separate Quality Assurance Project Plans (QAPPs) for the meteorological and the 

PM10 measurements. The EPA requirements for format and content have been followed in each 

QAPP and each has been approved by the APCD. 

The monitors provide hourly and daily PM10 concentrations. A summary of each monitor’s high 

concentration events is provided below and in Table 3.3-5.

• North Site: July 29, 2008 through present. There have been 12 high concentration PM10

events recorded during this period.

• Gossard: July 17, 2011 through present. There has been one high concentration PM10

event recorded during this period.

4 Draft EIS for the Gold Rock Mine Project Volume 2 BLM/NV/EL/ES/15-05+1793 February, 2015

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 3-17

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Chapter 3 – Affected Environment

Note that for comparisons of PM10 data to the NAAQS, the resulting concentration must be 

greater than 155 μg/m3 in order to be considered an exceedance. The PM10 NAAQS is a 

probabilistic standard and is defined as a level not to be exceeded more than once per year and 

is averaged over a three year period. As such, an exceedance of the daily value does not 

directly equate to an exceedance of the standard (or a non-attainment determination). 

Table 3.3-5 Colowyo Mine Network High PM10 Concentration Events

Event Number Date

North Site Daily 

Value of PM10, 

μg/m3

Gossard Daily 

Value of PM10, 

μg/m3

Calendar

Quarter

1 11/02/08 298 - 4

2 03/04/09 237 - 1

3 03/22/09 167 - 1

4 07/06/09 157 - 3

5 09/29/09 291 - 3

6 09/30/09 180 - 3

7 12/04/09 193 - 4

8 05/28/10 198 - 2

9 01/14/12 156 - 1

10 05/26/12 200 178 2

11 01/29/14 174 - 1

12 01/05/15 186 - 1

The monitoring of high concentration PM10 (Table 3-3.5) was addressed by CDPHE. The 

result was the development of a Colowyo Mine PM10 mitigation plan and modeling report 

(Colowyo 2010a). The report addressed Events 1-8 and identified that the PM10 sources for 

these events were: 1) an active coal pile (identified as ‘R3’) located close to the property 

boundary, 2) a parking area, 3) a maintenance area, and 4) an area referred to as the ‘boneyard’ 

that is used to store old vehicles and salvageable materials. The report demonstrated that the 

boneyard and R3 coal pile contributed 64 percent and 14 percent, respectively, of the PM10

source impact. Since the time of that report an updated Colowyo Mine Air Quality Mitigation 

Plan (Colowyo 2010a) called for the following: 1) increased dust controls at the boneyard, and 

2) the relocation of the R3 coal pile to a previously mined area that is below the level of the 

surrounding terrain. In October 2012, the R3 coal stockpile was relocated and the area was 

reclaimed and vegetated as a further dust mitigation measure. The mitigation strategy has 

significantly reduced monitored impacts.

The final three daily value exceedances, found in high concentration PM10 events (Table 3-3.5),

occurred in 2012 and 2014. Events 9 and 10 are potentially associated with natural or 

exceptional high wind events (Colowyo 2013b, Colowyo 2013c, and Colowyo 2013d). The 

January 29, 2014 event (Event 11) is currently being evaluated; site data indicates this event also 

qualifies as a natural or exceptional event. These reports detail the classification of a high 

concentration PM10 event as an event that should not be included in compliance determinations,

due to its classification as natural or exceptional, based on EPA guidelines for such events. This 

conclusion is supported by regional meteorological and air quality data from the event periods. 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 3-18

Mining Plan Modification Environmental Assessment
Chapter 3 – Affected Environment

3.3.8 Existing Air Pollutant Emission Sources

There are a total of 163 permitted air quality emission sources that are currently located within 

31 miles (50 km) of the Project Area. The region is generally rural and the emissions sources 

are dominated by mining, power generation, oil and gas production, and aggregate (sand and 

gravel) processing (CDPHE 2015a) (Appendix C). CDPHE (2015a) includes in its permits all 

sources of air quality emissions that are required by law to acquire a state air quality permit. 

Sources such as dust from dirt roads, agricultural operations, recreational activities and 

automobile use are not included because they are not regulated as stationary industrial sources 

but have the capacity to produce air quality emissions regionally.

3.3.9 Existing Coal Combustion Environment

Two existing coal fired electrical generating facilities are currently operating in the vicinity of 

the Project Area. The Craig Generating Station is located 4 miles (6 km) southwest of Craig, 

and twenty miles (32 km) northeast of the center of the Project Area. The Craig Generating 

Station is operated by Tri-State. It consists of three coal fired steam driven electric generating 

units (Units 1, 2, and 3). Total net electric generating capacity is 1,264 MW. The Hayden 

Generating Station, owned and operated by the Public Service Company of Colorado, is located 

4 miles (6 km) east of Hayden, and 39 miles (63 km) northeast of the center of the Project 

Area. It consists of two coal fired steam driven electric generating units (Units 1 and 2). Unit 1 

is rated at 205 MW and Unit 2 is rated at 300 MW. Both facilities receive their coal from a 

variety of sources. Each facility operates under a PSD major source permit issued by CDPHE. 

CDPHE requires the submission of actual emissions data for each facility on an annual basis

(Table 3.3-6).

Table 3.3-6 Regional Coal Fired Generating 2014 CDPHE Reported Actual 

Emissions Summary5

Location 2014 APENs Annual Actual Pollutant Emissions (tpy)

PM10 PM2.5 CO NO2 SO2 VOC1 HAPS

Craig Generating 

Station 172.2 121.1 1232.8 12091.0 3261.0 62.2 52.26

Hayden Generating 

Station 148.3 67.5 385.1 6483.6 2330.7 49.2 15.08

1 volatile organic compound

Colowyo has historically provided coal to a variety of end users, both regionally and nationally. 

Since 1977, the beginning of coal sales records, Colowyo has provided coal to approximately 

ninety different end users all over the nation (Appendix C ). In recent years, 2007 to present,

Colowyo has sold between 41 percent and 99 percent of their coal to the Craig Generating 

Station. The average annual sales to the Craig Generating Station between 2007 and 2014 

were 2.3 million tpy. This represents approximately 48 percent of the coal required for the 

Craig Generating Station’s annual coal needs. 

5 CDPHE APENS Reporting for 2014, provided electronically by CDPHE.

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 3-19

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Chapter 3 – Affected Environment

Colowyo has provided the Hayden Generating Station with coal in the past but only in small 

amounts ranging from below 100 tpy to a maximum of approximately 500 tpy. Colowyo has 

not provided any coal to the Hayden Generating Station since 2005.

The trend towards supplying coal exclusively to the Craig Generating Station seen from 2007 

to present is a deviation from historical coal sales within which Colowyo sold coal to a much 

wider array of end users. The coal distribution may become more consistent with the longer 

historical sales record as the Colowyo Mine continues to pursue additional clients,

3.3.10 Climate Change

The primary natural and synthetic GHGs in the Earth's atmosphere are water vapor, carbon 

dioxide (CO2), methane, nitrous oxide, and fluorinated gases. GHGs allow heat from the sun 

to pass though the upper atmosphere and warm the earth by blocking some of the heat that is 

radiated from the earth back into space. As GHG concentrations increase in our atmosphere 

they impact the global climate by further decreasing the amount of heat that is allowed to 

escape back into space. Many GHGs are naturally occurring in the environment; however, 

human activity has contributed to increased concentrations of these gases in the atmosphere. 

Carbon dioxide is emitted from the combustion of fossil fuels (i.e., oil, natural gas, and coal), 

solid waste, trees and wood products, and also as a result of other chemical reactions (e.g., 

manufacture of cement). Methane results from livestock and other agricultural practices and by 

the decay of organic waste in municipal solid waste landfills. Methane is also emitted during the 

production and transport of coal, natural gas, and oil. Nitrous oxide is emitted during 

agricultural and industrial activities, as well as during combustion of fossil fuels and solid waste. 

Fluorinated gases, while not abundant in the atmosphere, are powerful GHGs that are emitted 

from a variety of industrial processes and are often used as substitutes for ozone-depleting 

substances (e.g., chlorofluorocarbons, hydrochloroflourocarbons, and halons). 

The EPA tracks GHG emissions in the U.S. by source sector (e.g., industrial, land use, electricity 

generation, etc.), fuel source (e.g., coal, natural gas, geothermal, petroleum, etc.), and economic 

sector (e.g., residential, transportation, commercial, agriculture, etc.) (Table 3.3-7). With so 

many GHG emission sources nationally, from cattle to vehicles to electric power generators, 

no single source is likely to represent a significant percentage of national emissions. 

Nevertheless, GHG emissions for the U.S. are provided here in several ways. Table 3.3-7

shows GHG emissions (in CO2 equivalent [CO2e]) by economic sectors for 1995, 2000, and 

2007. Table 3.3-8 shows total U.S. emissions in 1995, 2000, and 2007 by gas and source and 

by CO2e; only the largest sources/sinks are shown for each gas. Note that, for CO2, “Land 

Use, Land-Use Change, and Forestry” represents a sink rather than a source, and is therefore 

in parentheses.

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 3-20

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Chapter 3 – Affected Environment

Table 3.3-7 U.S. Greenhouse Gas Emissions Allocated to Economic Sectors

Implied Sectors

1995

(million metric 

tons [mmt]

CO2e )

2000

(mmt CO2e)

2007

(mmt CO2e)

Electric Power Industry 1,989.0 2,329.3 2,445.1

Transportation 1,685.2 1,919.7 1,995.2

Industry 1,524.5 1,467.5 1,386.3

Agriculture 453.7 470.2 502.8

Commercial 401.0 388.2 407.6

Residential 368.8 386.0 355.3

U.S. Territories 41.1 47.3 57.7

Total Emissions 6,463.3 7,008.2 7,150.1

Land Use, Land-Use Change, and 

Forestry (Sink) (851.0) (717.5) (1,062.6)

Net Emissions (Sources and Sinks) 5,612.3 6,290.7 6,087.5

Table 3.3-8 U.S. Greenhouse Gas Emissions and Sinks

Gas/Source 1995

(mmt CO2e)

2000

(mmt CO2e)

2007

(mmt CO2e)

CO2 5,407.9 5,955.2 6,103.4

Fossil Fuel Combustion 5,013.9 5,561.5 5,735.8

Non-Energy Use of Fuels 137.5 144.5 133.9

Iron and Steel Production and Metallurgical 

Coke Production

103.1 95.1 77.4

Cement Manufacture 36.8 41.2 44.5

Natural Gas Systems 33.8 29.4 28.7

CH4 615.8 591.1 585.3

Enteric Fermentation 143.6 134.4 139.0

Landfills 144.3 122.3 132.9

Natural Gas Systems 132.6 130.8 104.7

Coal Mining 67.1 60.5 57.6

Manure Management 34.5 37.9 44.0

N2O 334.1 329.2 311.9

Agricultural Soil Management 202.3 204.5 207.9

Mobile Combustion 53.7 52.8 30.1

Nitric Acid Production 22.3 21.9 21.7

Stationary Combustion 13.3 14.5 14.7

Manure Management 12.9 14.0 14.7

HFCs, PFCs, and SF6 105.5 132.8 149.5

Substitution of Ozone Depleting Substances 28.5 71.2 108.3

HCFC-22 Production 33.0 28.6 17.0

Electrical Transmission and Distribution 21.6 15.1 12.7

Total Emissions 6,463.3 7.008.2 7,150.1

Land Use, Land-Use Change, and Forestry (Sink) (851.0) (717.5) (1,062.6)

Net Emissions (Sources and Sinks) 5,612.3 6,290.7 6,087.5

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 3-21

Mining Plan Modification Environmental Assessment
Chapter 3 – Affected Environment

Secondary GHGs do not have a direct atmospheric warming effect, but indirectly affect 

terrestrial radiation absorption by influencing the formation and destruction of tropospheric 

and stratospheric ozone, or in the case of SO2, the absorptive characteristics of the 

atmosphere. 

Additionally, some of these gases may react with other chemical compounds in the atmosphere 

to form compounds that are GHGs. For example, the roasting of molybdenite in ore 

processing is among the sources of indirect GHG emissions to the atmosphere, specifically SO2. 

Sulfur dioxide emissions are listed in Table 3.3-9. Levels of sulfur dioxide emissions have 

decreased since 1995 somewhat due to reductions in electricity generation, but primarily due 

to increased consumption of low sulfur coal from surface mines in the western states.

Table 3.3-9 U.S. Sulfur Dioxide (Indirect GHG) Emissions

Gas/Source GHG 1995 

(mmt)

GHG 2000 

(mmt)

GHG 2007 

(mmt)

SO2 16.89 14.83 11.73

Energy (combustion, etc.) 15.77 13.80 10.89

Industrial Processes 1.12 1.03 0.84

Chemical manufacturing 0.26 0.31 0.23

Metals processing 0.48 0.28 0.19

Other 0.37 0.37 0.29

NAAQS do not exist for GHGs. In its Endangerment and Cause or Contribute Findings for 

Greenhouse Gases under Section 202(a) of the CAA (FR EPA-HQ-OAR-2009-0171), the EPA 

determined that GHGs are air pollutants subject to regulation under the CAA. GHGs’ status 

as pollutants are due to the added long-term impacts they have on the climate because of their 

increased concentrations in the earth’s atmosphere. Ongoing scientific research has identified 

that anthropogenic GHG emissions impact the global climate. Industrialization and the burning 

of fossil fuels have contributed to increased concentrations of GHGs in the atmosphere. GHGs 

are produced from both the direct process of coal mining as well as from the combustion of 

the mined coal. The amount of GHG emissions associated with both of these processes varies 

greatly based on mining techniques and combustion methodologies used.

The EPA has taken action to regulate six key GHGs - CO2, methane, nitrous oxide, 

hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride. Because CO2 is the most 

prevalent of the regulated GHGs, the EPA references the potential impact of GHG emissions in 

terms of their equivalence to CO2 or CO2e. In addition to the EPA estimates, the International 

Energy Agency estimated global emissions of CO2e to be 29,000 mmt in 2008. On a regional 

scale, CDPHE (2014) estimated the total CO2e emissions in 2010 to be 130 million metric tons 

for the State of Colorado.

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 3-22

Mining Plan Modification Environmental Assessment
Chapter 3 – Affected Environment

The EPA has promulgated rules to regulate GHG emissions and the industries responsible 

under the Mandatory Reporting Rule (74 FR 56260, 40 CFR 98) and the Tailoring Rule (70 FR 

31514, 40 CFR 51, 52, 70, 71). Under the EPA’s GHG Mandatory Reporting Rule, coal mines 

subject to the rule are required to report emissions in accordance with the requirements of 

Subpart FF. Subpart FF is applicable only to underground coal mines and is not applicable to 

surface coal mines. Under the provisions of the Tailoring Rule (and a subsequent Supreme 

Court decision6, a facility would be subject to PSD permitting if it has the potential to emit 

GHGs in excess of 100,000 tpy of CO2e and the facility exceeded the PSD major source 

threshold for a criteria pollutant. For existing facilities this review would take place during any 

subsequent modifications to the facility. Based on emissions estimates for the Colowyo Coal 

Mine, no GHG reporting or permitting would apply to the facility; however, GHG reporting 

and permitting will apply to both the Craig and Hayden Generating Stations.

The first EPA regulation to limit emissions of GHGs imposed CO2 emission standards on lightduty vehicles, including passenger cars and light trucks. EPA is gathering detailed GHG emission 

data from thousands of facilities throughout the U.S. and will use the data in order to develop 

an improved national GHG inventory, as well as to establish future GHG emission control 

regulations. The EPA proposed regulations for GHG emissions from new and existing fossil 

fuel fired electric utility generating units in 2014 and plans to finalize the rules in 2015. 

Consequently, GHG emissions from fossil fuel fired power plants are likely to be increasingly 

regulated in the future. 

3.3.11 Black Carbon

Black carbon is a by-product of incomplete combustion of fossil fuels, biofuels, and biomass. It 

can be emitted when coal is burned, as well as through tailpipe emissions from engines that use 

diesel fuel (such as diesel trucks and locomotives). Black carbon is a likely by-product that 

would be emitted from haul trucks used during coal mining operations. Black carbon is an 

unregulated pollutant; however, the EPA does regulate diesel fuel quality, such that in recent 

years diesel fuel quality has been improved.

Black carbon emissions associated with coal combustion occur at the facility where the coal is 

burned, not where it is being mined. At the mine, black carbon occurs as a result of the use of 

diesel vehicles. Black carbon is a component of the anthropogenic climate phenomenon; 

however, it is very short-lived, staying in the atmosphere only a few days to a few weeks. 

Although short lived, while in the atmosphere black carbon is the most strongly light-absorbing 

component of particulate matter7

. Black carbon can absorb a million times more energy than 

carbon dioxide. Black carbon is a major component of “soot”, a complex light-absorbing 

mixture that also contains some organic carbon. 

6 Utility Air Regulatory Group v. EPA, ___ U.S. ___, 134 S. Ct. 2427 (June 23, 2014) 7 http://www.epa.gov/blackcarbon/basic.html

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 3-23

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Chapter 3 – Affected Environment

3.4 GEOLOGY

The Project Area is located in the north-central portion of the Danforth Hills coal field in the 

Rocky Mountain Coal Province of Tully (USGS 2008). This area is situated in the Wyoming 

Basin physiographic province, which is characterized by north- and east-trending ridges 

separated by steep canyons on the north, and to the south and west by steeply dipping, long 

and narrow hogbacks (CGS 2015, USGS 2008). Geology maps and stratigraphic sections can be 

found in various references (e.g., CGS 2015; USGS 2008; Colowyo 2007 (Figure 2.04.6-1, 

2.04.6-2, Map 7); KEC 2005).

The Project Area lies within a region that is deformed by several major folds, indicating that 

various coal seams will fold over and split. The Project Area occurs on both the southern and 

northern limbs of the generally southeast-trending asymmetrical Collom Syncline and extends 

north toward the southeast-trending Axial Basin Anticline and east toward the northnortheast-trending Elkhorn Syncline (Colowyo 2007, USGS 2008). Two smaller unnamed 

anticlines also cross the southern part of the Project Area and trend slightly more eastward. 

The complex structures seen in the Project Area are overlain by younger sedimentary 

sequences that reflect upward-diminishing deformation. Periodic movements along the 

ancestral Axial Fault located north of the Danforth Hills coal field are believed to have been the 

source of the major deformation observed in the Project Area. The latest movement along the 

fault was during the Laramide Uplift, a Tertiary orogenic event (35-70 million years ago) which 

led to the uplift of the modern Rocky Mountains. This episode of uplift was a compressional 

event that eventually formed faults and major folds, such as the Collom and Elkhorn Synclines, 

and the prominent Axial Basin Anticline (BLM 2006). 

3.4.1 Minerals

The coal seams in the Project Area are contained within the Upper Cretaceous Williams Fork 

Formation of the Mesaverde Group (BLM 2006, USGS 2008). The Mesaverde Group generally 

consists of a thinly to thickly interbedded succession of shale, siltstone, and sandstone that was 

deposited largely in a terrestrial environment. The Mesaverde Group is categorized into two 

formations: the overlying Williams Fork Formation, and the underlying Iles Formation (USGS 

2008). 

The Williams Fork Formation has been subdivided into five stratigraphic units. In ascending 

order these are the Fairfield coal group, barren interval, Goff coal group, Lion Canyon 

Sandstone, and Lion Canyon coal group. The Iles Formation has been subdivided into three 

stratigraphic units. In ascending order these are the Lower coal group, the Black Diamond coal 

group, and the Trout Creek Sandstone Member (USGS 2008). The Williams Fork and Iles 

Formations comprise a sedimentary rock sequence that originated from a deltaic and marginal 

marine depositional environment. The Trout Creek Sandstone Member consists of thick 

marine sandstone that represents the marine facies (beach) of the delta front. The high-quality, 

low-sulfur coal seams present in the Project Area occur within the Fairfield coal group of the 

Williams Fork Formation, which conformably overlies the Trout Creek Sandstone Member of 

the Iles Formation. The Williams Fork Formation is the surface rock covering most the Project 

Area. However, a narrow band of Iles Formation is found at the surface along the north limb of 

the Collom Syncline, with a small area of Mancos Shale occurring in the northern-most 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 3-24

Mining Plan Modification Environmental Assessment
Chapter 3 – Affected Environment

extension of the Project Area. Mancos Shale is also of Upper Cretaceous Age, and is the oldest 

of the geologic formations exposed in or near the Project Area. It is a thick marine, mostly 

massive sandy shale, with few thin-bedded coarser zones. Overlying these three units, 

particularly in stream valleys within the Project Area, are local occurrences of Quaternary 

alluvium, colluvium, and landslide deposits (Colowyo 2007). 

Coal seams X and A through G789 have been or will be mined in the South Taylor area 

(Colowyo 2007). This includes 11 or more coal seams or seam groups (X34, A, B12, C35, 

D12, E2, F1, F356, Fab, G3, and G789 seams); the total thickness of the mined unit, including 

overburden, coal, and interburden, is approximately 600 feet (KEC 2005).

3.5 WATER RESOURCES

3.5.1 Surface Water

The Project Area is located in the Lower Yampa River basin, which is part of the Colorado 

River system. Specifically, it is located primarily within three small drainage basins. From west 

to east, they are Wilson Creek, Taylor Creek, and Good Spring Creek (Figures 3-5a and 3-

5b). 

Additionally, the northernmost tip of the Project Area includes a very small section of the Jubb 

Creek watershed. All four of these streams flow generally northeast through narrow, steepsided valleys on their way to ultimately join the Yampa River. Jubb Creek and Taylor Creek 

both join Wilson Creek downstream of the Project Area. In turn, Wilson Creek flows into 

Milk Creek and then into the Yampa River. Good Spring Creek also flows into Milk Creek

several miles upstream of Milk Creek’s confluence with Wilson Creek. The morphology, flow 

characteristics, and water chemistry of these surface water resources are described in the PR02 

PAP (2007). The approved PAP (Colowyo 2015) incorporates the approved application for

PR02, which included the expansion into the South Taylor Pit area.

The morphology of the Project Area's surface water features is strongly influenced by geologic 

materials and geologic structure. The southern limb of the Collom Syncline dips gently to the 

north through the Project Area, and the pattern and orientation of most of the main tributary 

channels reflect this dip. These channels are relatively straight, having incised into the narrow 

valley fills and in some areas into bedrock associated with the Williams Fork Formation. Some 

of the upper reaches are bedrock controlled (Colowyo 2007). As is common with incised 

channels, many reaches have unstable cut banks and recently-slumped surfaces, although some 

riparian vegetation is also present. Outside the Project Area (downstream and to the north) 

stream valleys become less confined. 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 3-25

Mining Plan Modification Environmental Assessment
Chapter 3 – Affected Environment

The Wilson Creek drainage is characterized by narrow upland areas, steeply sloping hillsides, 

and flat valley bottoms. The tributary channels are incised into bedrock. Historically, landslide 

debris has accumulated in the valley bottom and currently conveys bedrock groundwater 

discharge and side valley runoff to recharge surface water flows via bank seeps (Colowyo 2007). 

Taylor Creek flows generally parallel to Wilson Creek within the Project Area. Its watershed 

slopes are variable, but Taylor Creek itself is relatively steep. Further, bedrock limits incision 

and bank sloughing in this stream channel. Good Spring Creek’s watershed is characterized by 

steep sloping uplands with exposed bedrock and narrow, flat valley bottoms. Incision has 

created deep gullies in some stream reaches, along with bank sloughing and resultant channel 

widening. 

Wilson and Good Spring creeks are both perennial streams; the West Fork of Good Spring 

Creek also flows perennially due to a number of perennial springs. Taylor Creek flows 

intermittently (Colowyo 2007). Streamflows in and near the Project Area depend upon 

watershed runoff, seep and spring discharge, and/or groundwater-fed gaining reaches.

Monitoring records show that flows vary seasonally, with peaks generally snowmelt-based. For 

example, the U.S. Geological Survey (USGS) monitored stream flows in Wilson Creek north of 

the Project Area (Station #9250507) between 1981 and 1992. Streamflows ranged from 0 to 

352 cubic feet per second (cfs). Another site on Wilson Creek (Station #9250600), located at 

nearly the same location, was monitored between 1975 and 1980, with flows ranging from 0.15 

to 82 cfs. These data reflect the extreme variation in flow that can occur seasonally or annually 

in this area, and also indicate the importance of a long record when characterizing flow regimes 

(e.g., the four-year record from #9250600 compared to the (still relatively short) 10-year 

record from #9250507 show high flows for the period of record that were very different; 

neither may be truly representative). The USGS also monitored Taylor Creek (Station 

#09250510) flows between 1976 and 1992, and data show streamflows ranging from essentially 

0 cfs to 18 cfs. For about three years in the mid-1970s, the USGS also monitored flows in 

Good Spring Creek (Station 09250400); peak flow was 58 cfs and the minimum was near 0 cfs 

(USGS 2015a).

All three of these streams were determined to have a base flow of 1 cfs or less, based upon a 

study that took place between 1978 and 1982 (Colowyo 2007). More recently (1996 and 

1997), streamflows were monitored monthly at various other locations in these three streams, 

upstream of the USGS sites, in and near the Project Area (Colowyo 2007) (Figures 3-5a and 

3-5b). Flows ranged from 0.2 cfs at Upper Wilson Creek (site UWC) to 41.25 cfs at Lower 

Wilson Creek (site LWC). Taylor Creek flow ranged from 0.01 cfs at Lower Taylor Creek (site

LTC) to 2.04 cfs at Upper Taylor Creek (site UTC), and rates were considered typical of 

intermittent streams in the area. Good Spring Creek flows during that same period ranged 

from 0.85 cfs at New Upper Good Spring Creek (site NUGSC) to 17.0 cfs at Lower Good 

Spring Creek (site LGSC). Additional monitoring in the West Fork of Good Spring Creek was 

done in 1999 and 2000 (Colowyo 2007). Measured flows ranged from 0.18 cfs at Upper West 

Fork Good Spring Creek (site UWFGSC) to 7.0 cfs at Lower West Fork Good Spring Creek 

(site LWFGSC). 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 3-26

Mining Plan Modification Environmental Assessment
Colorado

Taylor Creek

PST-06-17

MWST-06-04

84-B-TC

MW 95 01

MW 05 03

W 95 02 Streeter

Fill Well

MT 95 01

NGSW

UL 95 40

UL 95 45

MT 95 02

MW 95 02

Gossard

Well

A-8

A-6 (South

Good Spring

Well)

A-7

3-93-17-143

WFS-7A

WFS-4

WFS-1

GSCS-1

3-93-17-432

3-93-20-212

3-93-17-144

3-93-17-142

3-93-28-122

3-93-18-434

(SPRLW-01)

SPRLW-02

WFS-7

3-93-20-215 3-93-20-213

3-93-20-214

WFS-5A

WFS-5

3-93-29-234

WFS-2

3-93-28-212(FW)

3-93-28-131

3-93-28-131

3-93-29-233

LMWC

LGSC

UMWC

UTC

UWC

LWC

LTC

NUGSC

EFGSC

UWFGSC

LWFGSC

39615

66375

199759

69728

36215

37213

9274

175220

24745

37214

175217

Section

16 Pond

Outfall: 009

West Taylor

Pond

Outfall: 011

Section

28 Pond

Outfall: 012

SCS

SCS

SCS

Area Shown in Detail on Figure 3-5b

13

51

32

17

180

Moffat

Rio Blanco

Future Planned

Disturbance

Little Creek

James Creek

Wilson Creek

East Taylor Creek

Elkhorn Creek

East Fork Jubb

Creek

Good Spring Creek

West Taylor Creek

East Fork Wilson Cree k

Taylor Creek

Good Spring C reek

Wilson Cre ek

Hydrology

3-5a

Colowyo Coal Mine, South Taylor/Lower Wilson

Permit Expansion Area Mining Plan Modification

Environmental Assessment

Rio Blanco & Moffat Counties

Colorado

0 4,000 8,000

Feet

1:48,000 (At Original document size of 11x17)

Permited Domestic

Well

Permited Stock

Watering Well

Borehole

Seep

Spring

Ground Water

Monitoring Site

Surface Water

Monitoring Site

Stream

Drainage Boundary

Alluvial Valley Floor

Project Area

Future Planned

Disturbance

Actual Disturbance

since PR 02

East Taylor Fill

West Taylor Fill

Sediment Pond

Sediment Control

Structure (SCS)

County Road

Highway

County Boundary

Project 

Location

Notes

1: Coordinate System: NAD 1983 UTM Zone 13N

2: Service Layer Credits: Copyright:© 2013 National

Geographic Society, i-cubed

Disclaimer: Figure prepared for OSMRE by Stantec. Stantec assumes no

responsibility for data supplied in electronic format. The recipient

accepts full responsibility for verifying the accuracy and completeness

of the data. The recipient releases Stantec, its officers, employees,

consultants and agents, from any and all claims arising in any way from

the content or provision of the data.

Project Location

Project

Figure No.

Title
Colorado

Section

16 Pond

West

Taylor

Pond

Section

28 Pond

PST-06-17

MWST-06-04

A-8

A-6 (South

Good Spring

A-7 Well)

3-93-17-143

WFS-7A

WFS-4

WFS-1

GSCS-1

3-93-17-432

3-93-20-212

3-93-17-144

3-93-17-142

3-93-28-122

3-93-18-434

(SPRLW-01)

WFS-7

3-93-20-215

3-93-20-213

3-93-20-214

WFS-5A

WFS-5

3-93-29-234

WFS-2

3-93-28-212(FW)

3-93-28-131

3-93-28-131

3-93-29-233

NUGSC

EFGSC

UWFGSC

LWFGSC

37214

SCS

SCS

SCS

13

84-B-TC

Moffat

Rio Blanco

Future Planned

Disturbance

East Taylor Creek

Good Spring Creek

James Creek

West Taylor Creek

Outfall:

011

Outfall:

009

Outfall:

012

Hydrology

3-5b

Colowyo Coal Mine, South Taylor/Lower Wilson

Permit Expansion Area Mining Plan Modification

Environmental Assessment

0 1,600 3,200

Feet

1:19,200 (At Original document size of 11x17)

Permited Stock

Watering Well

Borehole

Seep

Spring

Ground Water

Monitoring Site

Surface Water

Monitoring Site

Outfall Location

Stream

Drainage Boundary

Alluvial Valley Floor

Project Area

Future Planned

Disturbance

Actual Disturbance

since PR 02

East Taylor Fill

West Taylor Fill

Sediment Pond

Sediment Control

Structure (SCS)

Highway

County Boundary

Project 

Location

Notes

1: Coordinate System: NAD 1983 UTM Zone 13N

2: Service Layer Credits: Copyright:© 2013 National

Geographic Society, i-cubed

Disclaimer: Figure prepared for OSMRE by Stantec. Stantec assumes no

responsibility for data supplied in electronic format. The recipient

accepts full responsibility for verifying the accuracy and completeness

of the data. The recipient releases Stantec, its officers, employees,

consultants and agents, from any and all claims arising in any way from

the content or provision of the data.

Figure No.

Title

Rio Blanco & Moffat Counties

Colorado

Project Location

Project
Chapter 3 – Affected Environment

Local seeps and springs, resulting from groundwater discharge, may also contribute to surface 

water flows within the Project Area. Inventories covering the general area were undertaken in 

1985 and 1997 (Colowyo 2007), and numerous seeps and springs were observed and 

characterized. In general, seep and spring discharge occurred: 1) with relatively deep soil 

accumulation immediately upslope and shallow bedrock downslope, 2) within valley bottom 

deposits, or 3) from sheer bedrock faces on hillsides. Colluvium and alluvium associated with 

the first two scenarios may mask or contribute to bedrock sources of the springs. Where the 

source was determined to be bedrock-related, the majority of the springs appeared to be 

contact springs that issue from the Williams Fork Formation. Contact springs are common 

where alternating rock sequences result in preferential flow paths developing along the 

interface of two layers with different hydraulic conductivities. Further, the springs in the West 

Fork of Good Spring Creek are the result of converging bedrock dips caused by an unnamed 

syncline that occurs along the channel (Colowyo 2007). 

Figures 3-5a and 3-5b show the locations of identified seeps and springs that were located in 

the Project Area or within one mile of its boundary during seep and spring surveys done as part 

of the initial mine permitting work. Based upon measurements made in 1985 (Colowyo 2007), 

springs were estimated to contribute up to 1.9 cfs to flow in the West Fork of Good Spring 

Creek, and about 1cfs to surface flows in the mainstem of Good Spring Creek during peak flow 

periods. Contributions to surface flows from spring discharge during baseflow periods were 

much less, ranging from 0.03 cfs to 0.06 cfs at site WFGSC, and 0.03 cfs in the mainstem. 

Water quality data for streams and selected seeps/springs were also collected during baseline 

monitoring (generally between 1996 and 1999, when flows were sufficient to do so). The 

stream sites (Figure 3-5a) show increasing total dissolved solids (TDS) concentrations in the 

downstream direction. For example, UWC had an average TDS of 590 mg/L during the mid1990s baseline monitoring and LWC had an average TDS of 815 mg/L during the same period. 

While there has been no surface mining disturbance that has occurred in the Wilson Creek 

drainage, two sites (Upper Middle Wilson Creek [site UMWC] and Lower Middle Wilson 

Creek [site LMWC]) in the drainage had TDS averages of 685 and 790 mg/L, respectively. 

Further, TDS concentration varies seasonally with highest concentrations at any given stream 

site generally occurring during the low flow season (i.e., winter). The TDS reported at 

monitored springs and seeps was on average higher than reported in the streams. For example, 

at WFS-2 (Figures 3-5a and 3-5b), six samples had TDS concentrations ranging from a 

minimum of 1,590 mg/L to a maximum of 3,060 mg/L, with an average of 2,465 mg/L. This 

spring is located near the southern boundary of the Project Area in the West Fork Good 

Spring Creek watershed.

Iron concentrations have been elevated in the Yampa River downstream of Craig for a number 

of years, and as a result the lower Yampa is on the State’s 303(d) list of impaired waters 

(CDPHE 2012a). EPA’s Effluent Limitations Guidelines for coal mining (40 CFR Part 434) 

include iron, but note that high concentrations of total iron can be found in western coal 

regions. In fact, the development document (EPA 2001) notes that “In natural undisturbed 

conditions, surface water samples in the arid/semiarid western United States can register values 

for total iron as high as 40,000 mg/L (or 4%), due to the sediment that is collected as part of 

the water sample.” Colowyo’s baseline monitoring for PR02 (Colowyo 2007) indicated that 

dissolved iron concentrations in both the bedrock and alluvial aquifers are elevated. Further, 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 3-29

Mining Plan Modification Environmental Assessment
Chapter 3 – Affected Environment

baseline monitoring in Wilson, Taylor, and Good Spring creeks showed that as a whole total 

recoverable iron concentrations are on average below the USEPA aquatic life standard of 1.0 

mg/L, but individual analyses are often greater than the standard (Colowyo 2007). More 

specifically, Good Spring and Taylor Creek iron concentrations had lower mean total 

recoverable iron concentrations (0.6 to 0.8 mg/L and 0.3 to 0.6 mg/L, respectively) than Wilson 

Creek had (0.7 to 5.6 mg/L) (Colowyo 2007). These localized groundwater and surface water 

data indicate that iron contributions from the three creeks and associated alluvial groundwater 

in the area may be incrementally contributing to iron loading in the Yampa, but are likely a 

minor component and not directly responsible for the impairment.

Selenium is another constituent of interest in the region’s surface waters. Pre-project, 

background dissolved selenium rates in Lower Taylor Creek (site LTC) ranged from 0.001 mg/L 

to 0.016 mg/L. Pre-project background dissolved selenium rates ranged from 0.0005 mg/L to 

0.03 mg/L 0.015 mg/L in lower Good Springs Creek (site LGSC), and from 0.001 mg/L to 0.036 

mg/L in North Upper Good Springs Creek (site NUGSC) (Colowyo 2015). Water quality data 

collected from the Yampa River below Craig (USGS Station 09247600) between 1991 and 2011 

(n=91) showed that close to half of the values were reported at less than the laboratory 

reporting level, and the maximum reported was 17.0 micrograms per liter (0.017 mg/L) (USGS 

2015b). The chronic aquatic life standard for total selenium is 0.005 mg/L (CDPHE 2012b).

Pollutants conveyed in the atmosphere can deposit directly into waterbodies or onto upland 

land surfaces and in turn be carried in runoff to waterbodies. This deposit and conveyance can 

degrade water quality, even at great distances from the source or the airborne pollutant. 

Mercury is once such pollutant and its “deposition in a given area depends on mercury emitted 

from local, regional, national, and international sources” (EPA 2015a). Unlike many other 

pollutants, the primary source of mercury in streams is likely to be via atmospheric deposition 

(USGS 2015c). EPA’s latest published National Emissions Inventory (EPA 2014) indicates that coalfired electricity generation units were the largest source of mercury emissions in 2011. The common 

way of assessing a potential mercury problem in surface waters is using fish tissue, as mercury 

bioaccumulates. This is discussed in more detail in Section 4.9.1, including the fact that fish 

tissue analyses within the Yampa River watershed have shown elevated levels. Water quality 

data collected from the Yampa River below Craig (USGS Station 09247600) between 1991 and 

2003 (n=52) showed that the majority of values were reported at less the laboratory reporting 

level, and the maximum reported was 0.10 micrograms per liter (USGS 2015b). The State of 

Colorado chronic aquatic life water quality standard for mercury is 0.01 micrograms per liter 

(0.00001 mg/L) (CDPHE 2012b).

3.5.2 Groundwater

Groundwater in and near the Project Area may be associated with: 1) perched aquifers of 

limited extent within bedrock of the Williams Fork Formation; 2) localized alluvial/colluvial 

aquifers, primarily along stream channels; and 3) the regional Trout Creek aquifer. Where 

found in area bedrock, groundwater is largely controlled by the existence of fractures instead of 

primary permeability within the rock composition itself. In particular, groundwater tends to 

occur in the synclinal axis of the folds in the area because there is increased fracturing in these 

areas. Each of the three units associated with groundwater are described briefly below.

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 3-30

Mining Plan Modification Environmental Assessment
Chapter 3 – Affected Environment

The Williams Fork Formation is thick (up to 1,200 feet) and consists of interbedded coal, shale, 

sandstone, siltstone, and mudstones. Some of these beds contain localized groundwater and 

others serve as confining units. Where groundwater is found in the more permeable beds, it 

forms isolated perched lenses of limited extent and minimal production; thus the Williams Fork 

Formation is not considered to be a major aquifer in the region (Colowyo 2007). Hydraulic 

conductivity and transmissivity of the perched zones of the interburden within the Williams 

Fork Formation vary greatly (by up to 1 and 2 orders of magnitude, respectively), and is 

attributed to variability in the degree of rock fracturing (Colowyo 2007). In nearby mined areas 

where these perched zones have been intercepted, they have rapidly drained. Important among 

the less permeable beds is the KM Layer (also known as the Yampa Bed) of the Williams Fork 

Formation. It is a laterally-continuous, low-permeability clay bed that was formed from altered 

volcanic ash. The KM Layer is located beneath the mineable coal seams and serves as an

aquitard separating the beds within the mined coal sequence from the underlying rocks 

including the lowest part of the Williams Fork Formation and the Trout Creek Sandstone. 

Additionally, geologic structure in the Project Area influences groundwater flow through the 

Williams Fork Formation. In the southern part of the Project Area, near the South Taylor pit, 

the presence of an unnamed syncline and an unnamed anticline have axes that plunge toward 

the northeast. These features create a dip-slope towards Good Spring Creek, which in turn 

results in groundwater discharge locally from the Williams Fork Formation (Colowyo 2007).

Beneath the Williams Formation is the Iles Formation. An upper member of the Iles Formation, 

known as the Trout Creek Sandstone, forms the uppermost aquifer of regional extent within 

and near the Project Area. While previous drilling in the area found the Trout Creek 

Sandstone to be dry in one location (Well 84-B-TC, Figures 3-5a and 3-5b) other locations 

closer to the axis of the Collom Syncline were saturated and had transmissivity and hydraulic 

conductivity values indicative of moderate permeability (Colowyo 2007). The potentiometric 

surface associated with this confined aquifer has an elevation of between 7,050 and 7,100 feet 

amsl where it is beneath the South Taylor mining area (Colowyo 2007). In this area, the Trout 

Creek Sandstone aquifer underlies the lowest coal seam to be mined by approximately 590 

feet. 

The alluvial materials found along Project Area streams also generally contain and transmit

groundwater. Colowyo (2007) specifically mapped alluvial aquifers along Wilson Creek, West 

Fork Good Springs Creek, and Good Springs Creek within the Project Area as well as outside 

of it. Along Taylor Creek, an alluvial aquifer is identified primarily downstream of the Project 

Area, with only a very short reach occurring within the boundary. Alluvial aquifers in and near 

the Project Area have moderate to high permeability where encountered, with a wide range of 

hydraulic conductivity values. Colowyo considers stream-laid alluvium as well as colluvium 

within the alluvial category.

Groundwater has been monitored in or near the Project Area since 1983, with wells 

established in each geologic unit where groundwater may occur (alluvium, certain lenses of the 

Williams Fork Formation, and the Trout Creek Sandstone). These monitoring data have 

included elevation (i.e., depth to water) and/or water quality. Figures 3-5a and 3-5b show 

groundwater monitoring locations in the area, from various previous investigations, but not all 

of these sites have been monitored over the same period of time. As expected, groundwater 

chemistry in the area varies with the geologic source. The Williams Fork Formation tends to 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 3-31

Mining Plan Modification Environmental Assessment
Chapter 3 – Affected Environment

produce calcium- or sodium-bicarbonate water type, and a low to moderate concentration of 

TDS (ranging from 440 to 640 mg/L in a 1985 study and ranging from 890 to 970 in a mid-1990s 

study (Colowyo 2007)). The Trout Creek Sandstone groundwater data varies more in regard 

to water type (ranging from sodium-sulfate, sodium-bicarbonate type, to mixed-cationbicarbonate with equal percentages of calcium, magnesium, and sodium, The TDS range in that 

aquifer ranged from 600 to 710 mg/L in the 1985 study and from 680 to 1,180 in the mid-1990s 

study (Colowyo 2007). Water quality in the bedrock aquifers does not appear to substantially 

vary seasonally, based upon a 1985 investigation (Colowyo 2007). Groundwater produced in 

the alluvial valley fill has varying water quality, but is generally typed as magnesium-sulfate or 

magnesium- and/or calcium-bicarbonate. TDS is moderate to high, with concentrations ranging 

from 420 to 3,780 mg/L, and shows seasonal variations. Colowyo 2007 also includes data 

tables summarizing TDS from studies subsequent to the 1985 investigation and those later 

results are encompassed within the 1985 range.

These small perched aquifers associated with the Williams Fork Formation have no beneficial 

uses in or near the Project Area, primarily due to their size and lack of sufficient yield. The 

Trout Creek Sandstone is used regionally, but its TDS concentration, as well as elevated iron 

and manganese, limit use for domestic water. Depth to water in the Project Area also hinders 

usage of this bedrock groundwater. The mine’s potable water supply well located about 2 miles

(3 km) northeast of the Project Area (completed at a depth of 1,000 feet in 2004) produces less 

than 4 gallons per minute (gpm) (Colowyo 2007). Similarly, the alluvial aquifer in the area often 

has similar water quality issues that hamper its use for domestic use. There are several nonColowyo registered/permitted domestic or stock watering wells located within a mile of 

Project Area (Colowyo 2007) (Figure 3-5a).

Pollutants contained in the residuals from the combustion of coal in power plants and disposed 

of through burial can be conveyed into groundwater aquifers. Colowyo’s coal is transported 

from the mine by rail to coal markets, including the Craig Generating Station located 

approximately 26 miles (42 km) northeast of the Colowyo Mine. Coal combustion residuals 

(CCRs) generated as part of the coal combustion process at the Craig Generating Station 

include boiler fly ash, boiler bottom ash, and scrubber sludge. These CCRs produce leachate 

that contains elevated levels of aluminum, barium, chromium, boron, and molybdenum (Koehler 

2002). These CCRs are disposed of in a disposal site at the Trapper Mine located 

approximately one mile from the Craig Generating Station. The disposal site is under the 

jurisdiction of SMCRA and is approved to receive CCRs under a Certificate of Designation 

from Moffat County, with regulatory oversight from CDPHE.

SMCRA and CDHPE monitoring and reporting requirements apply to the Trapper Mine 

disposal site. CCRs generated at the Craig Generating Plant and disposed of at the Trapper 

Mine disposal site must be placed at least 10 feet above the projected post-mining groundwater 

saturation zone. The CCRs are covered with 6 feet of cover (5 feet of overburden and 1 foot 

of topsoil) and any reconstructed permanent surface water drainage is located a minimum of 50 

horizontal feet from the CCRs (Koehler 2002). Modeling of the site has been conducted to 

provide data associated with cross-stratal migration of CCR leachate, travel time of the CCR 

leachate, and groundwater/surface water interaction associated with the disposal site; the 

studies indicated that the low permeability of the CCRs and the low infiltration rate of 

precipitation should limit the risk of water movement through and from the CCRs (Kaldenbach 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 3-32

Mining Plan Modification Environmental Assessment
Chapter 3 – Affected Environment

et al. 2001, Koehler 2002). A groundwater monitoring network is in place to ensure that the 

placement of CCRs in the disposal site is effective in isolating or immobilizing leachate from the 

CCRs. The results of the monitoring indicate that the water quality downgradient of the CCR 

disposal site is similar to the water quality in other areas of the Trapper Mine that are not 

associated with CCR disposal; only low levels of the contaminants of concern were detected as 

a result of the final sampling in 2002 (Koehler 2002). 

3.6 VEGETATION

Vegetation surveys that cover the Project Area have been conducted from 1985 to 2005 

(Colowyo 2007). The results of those surveys as they relate to the Project Area are depicted 

in Table 3.6-1 (Colowyo 2007). The acreages include portions of land added by PR02 as well 

as areas that were previously part of the approved permit boundary. Therefore, the overall 

acreage is larger than the amount of land added to the permit boundary from PR02. The 

location of the vegetation communities are shown in Figure 3-6. A discussion of each 

vegetation community is presented below and taken from the approved permit (Colowyo 2007 

and 2012a). 

Table 3.6-1 Vegetation Communities within the Project Area

Vegetation Community Acres Percent of Total

Mountain Shrub (mesic and xeric) 4,090.5 57.6

Sagebrush (mesic and xeric) 2,334.4 32.8

Aspen Woodland 292.6 4.1

Juniper Shrub 140.9 2.0

Bottomland 81.2 1.1

Cropland 81.1 1.1

Grassland 50.3 0.7

Riparian 38.5 0.5

Pond 6.0 0.1

Totals 7,115.5 100.0

Source: Colowyo 2007

3.6.1 Mountain Shrub Community

The mountain shrub community covers approximately 4,090.5 acres, or 57.6 percent of the 

Project Area. This community is primarily found at higher elevations occupying the relatively 

flat uplands, steep southern-facing slopes (xeric sub-types), and steep northern-facing slopes 

(mesic sub-type). A total of 102 plant species were found in the mountain shrub community 

during surveys. Dominant shrub species found in the community include mountain snowberry

(Symphoricarpos oreophilus), Gambel oak (Quercus gambelii), serviceberry, and mountain big 

sagebrush (Atremisia tridentata ssp. vaseyana). Grasses and forbs found in this community 

include bluegrass (Poa spp.), cheatgrass (Bromus tectorum), and tailcup lupine (Lupinus caudatus). 

In more mesic sites, aspen may intergrade with this community. Except where this community 

is over-mature and therefore, largely impenetrable, it provides excellent cover, forage, and 

browse for resident deer and elk herds.

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 3-33

Mining Plan Modification Environmental Assessment
Chapter 3 – Affected Environment

3.6.2 Sagebrush Community

The sagebrush vegetation community covers approximately 2,334.4 acres, or 32.8 percent of

the Project Area. This community is principally found at lower elevations occupying the 

relatively flat uplands or benches, some steeper north-facing slopes (mesic sub-types), and 

steeper southeast-facing slopes (xeric sub-types). A total of 93 plant species were found in the

sagebrush community. Common shrub species include mountain big sagebrush, Wyoming big 

sagebrush (Atremisia tridentata ssp. wyomingensis), mountain snowberry, snakeweed (Gutierrezia 

sp.), and low rabbitbrush (Chrysothamnus viscidiflorus). Grasses and forbs found in these areas 

include Japanese brome (Bromus japonicus), western wheatgrass (Pascopyrum smithii), Sandberg 

bluegrass (Poa sanbergii), and crested wheatgrass (Agropyron desertorum). In several areas near 

Sections 15 and 16, range improvements have been made which have altered the vegetation. 

The large shrubs have been removed to allow the understory species to be more productive. 

The practice has removed most of the serviceberry and in the process, most of the sagebrush. 

3.6.3 Aspen Woodland Community

The aspen woodland community covers approximately 292.6 acres, or 4.1 percent of the 

Project Area. This community is commonly located on high elevation, steep slopes, and 

drainage bottoms that generally have northeast to northwest aspects. During surveys, a total of 

63 plant species were found in this community. Along with aspen common species include 

mountain brome (Bromus marginatus), blue wild rye (Elymus glaucus), bluegrass (Poa agassizensis), 

nettleleaf giant hyssop (Agastache urticifolia), mountain snowberry, and chokecherry (Prunus 

virginiana).

The aspen community in the Project Area appears to have been noticeably affected by the 

recent drought. A high percentage of mature aspen trees have recently died leading to a lower 

live tree density and a dense understory of chokecherry and mountain snowberry. The aspen 

stands in more mesic sites are healthy, whereas stands that occupy or have expanded to more 

xeric sites have lost most of their mature overstory. Young aspen seedlings and saplings are 

found in these areas and will likely see a return to a denser aspen tree overstory. 

3.6.4 Juniper Shrub Community

The juniper shrub community covers approximately 140.9 acres, or 2.0 percent of the Project 

Area. This community is located on the steeper slopes in the drier, rockier, and skeletal soil 

that cover the northern portions of the Project Area. The dominant species occurring in this 

community include junipers (Juniperus spp.), Wyoming big sagebrush, mountain big sagebrush, 

mountain snowberry, crested wheatgrass, cheatgrass, Sandberg bluegrass, and western 

wheatgrass.

The juniper shrub community is visually dominated by juniper trees with assorted shrubs, 

grasses, and forbs occupying the areas between the trees. Most of this community is located 

on steep, relatively barren and erodible soils along the drier, northern edge of the Project Area. 

A small portion of this community can be found on the flat tops on the slopes where it 

intergrades into the sagebrush dominated uplands. The juniper trees appear healthy and 

expanding into both the mesic and xeric sagebrush areas that are adjacent to this community 

type.

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Aspen

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Notes

1: Coordinate System: NAD 1983 UTM Zone 13N

2: Service Layer Credits: Copyright:© 2013 National

Geographic Society, i-cubed

Disclaimer: Figure prepared for OSMRE by Stantec. Stantec assumes no

responsibility for data supplied in electronic format. The recipient

accepts full responsibility for verifying the accuracy and completeness

of the data. The recipient releases Stantec, its officers, employees,

consultants and agents, from any and all claims arising in any way from

the content or provision of the data.

Project

Figure No.

Title

Rio Blanco & Moffat Counties

Colorado

Project Location
Chapter 3 – Affected Environment

3.6.5 Bottomland Community

The bottomland community covers approximately 81.2 acres, or 1.1 percent of the Project 

Area. This community is largely a physiographic type that exhibits an aggregate of vegetation 

sub-types (wetland, sagebrush, riparian bottom, grassland, and occasionally mountain shrub) 

that are found in the relatively flat alluvial and colluvial deposits along the numerous drainages 

within the Project Area. The bottomland community generally has deep soils with higher 

moisture levels due to the external contributions from slope outwash, flood flows, lateral 

subirrigation, and the occasional seeps and springs. During field surveys, a total of 92 species 

were observed in this community. Dominant shrubs include rubber rabbitbrush (Chyrsothamnus 

nauseosus), basin big sagebrush (Artemisia tridentata var. tridentata), mountain snowberry, and 

silver sage (Artemisia cana). Grasses and forbs that may be present include western wheatgrass, 

Japanese brome, thickspike wheatgrass (Agropyron dasystachyum), and cheatgrass.

3.6.6 Grassland Community

The grassland community covers approximately 50.3 acres, or 0.7 percent of the vegetation in 

the Project Area. This community is predominately an early-seral community found in the flat 

uplands where natural and prescribed burns have removed the sagebrush or mountain shrub 

overstory vegetation and the usually sub-dominant grasses have flourished. Occasional small 

patches of the grassland community can be found along high elevation ridges and summits 

where thin soils and high winds have inhibited shrub densities. The dominant plant species 

observed in the grassland community include: western wheatgrass, cheatgrass, Sandberg 

bluegrass, Japanese brome, and prairie pepperweed (Lepidium densiflorum). Shrubs which may 

be present in low amounts include holly grape (Mahonia repens), low rabbitbrush, mountain 

snowberry, and mountain big sagebrush.

The grassland community type in the Project Area has been divided into two arbitrary subtypes 

based on whether or not the area is naturally lacking a shrub component or was naturally 

burned in the past (grassland). The sagebrush reduction areas are generally located on the 

relatively flat upland areas surrounded by overmature stands of mountain sagebrush and just 

north of the transition zone between mountain shrub and sagebrush zones. Most of the older 

sagebrush reduction areas now contain enough reinvading sagebrush to be classified as 

sagebrush, but the more recent areas exhibit only a few plants and can still be classified as 

grassland. The naturally occurring grasslands are scattered throughout the Project Area in 

small patches. Some of these patches are located along high-elevation, wind-swept ridgelines,

and summits where thin soils favor grass and forb development over shrubs. Annual bromes 

have invaded some of the past natural burn areas (especially at lower elevations) and have 

slowed the re-invasion of sagebrush into these areas.

3.6.7 Riparian

Riparian vegetation accounts for approximately 38.5 acres, or 0.5 percent of the vegetation in 

the Project Area. The majority of this vegetation type is found along Wilson Creek and is 

dominated by boxelder (Acer nugundo) trees of various diameter classes. The understory is 

similar to the bottomland vegetation type. Other species commonly found in this area include 

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Canada thistle (Cirsium arvense), rubber rabbitbrush, Great Basin wildrye, burdock (Arctium 

spp.), and Kentucky bluegrass (Poa pratensis).

3.6.8 Other Communities

The remaining mapped vegetation communities (cultivated fields/cropland and ponds) cover a 

total of 87.1 acres, or 1.2 percent of the Project Area. These areas have been generally altered 

from their natural state. As such, many non-native species may occur in these areas as well as 

some native vegetation. 

3.6.9 Noxious Weeds

Noxious weeds are those species which have been determined by the State of Colorado as 

detrimental to the environment or agriculture. Since 1990 the State’s natural and agricultural 

resources have been protected by the Colorado Noxious Weed Act (35-5.5 CRS). The 

noxious weed list is prioritized into three categories, A, B and C. List A plants are designated 

for elimination on all county, state, federal, and private lands. List B includes plants whose 

continued spread should be stopped. List C plants are selected for recommended control 

methods. There are currently 76 species on the State’s noxious weed list (CWMA 2015). The 

Moffat County Board of County Commissioners adopted the Moffat County Undesirable Plant 

Management Plan on November 25, 1991 to formalize weed control procedures within the 

County (Moffat County 2001). This plan details methods of Integrated Plant Management to 

implement weed management within the County. Since the late 1990s, there has been a weed 

management partnership that includes Moffat County Weed and Pest Department, Colowyo, 

and several other agencies and individuals (J. Comstock, personal communication, July 5, 2015).

During vegetation surveys conducted in 1985, a total of four noxious weed species were 

observed. Those species include quackgrass (Elymus repens), musk thistle (Carduus nutans), 

houndstongue (Cynoglossum officinale), and Canada thistle. In general, when these species were 

observed, their densities were low and were only occasionally in sufficient quantities to be 

detected by ground cover sampling. 

3.7 WETLANDS AND RIPARIAN ZONES

Wetlands and riparian areas serve an important role in the environment. Often, these areas 

are used by wildlife as refuge, and they increase the biodiversity in a given area by increasing 

habitat diversity. Surveys for wetlands and riparian areas were conducted within the vegetation 

study area (Section 3.6), and surveys for wetlands and Waters of the U.S. (WOTUS) were 

conducted over some or all of the Project Area (JBR 1997a, JBR 1997b).

3.7.1 Wetlands and Riparian Zones

Management of wetlands is generally under the jurisdiction of the U.S. Army Corps of Engineers 

(USACE). To be considered a jurisdictional wetland, an area must meet three criteria: hydric 

vegetation, hydric soil indicators, and the presence (or evidence) of inundation. Surveys 

conducted for wetlands within the Project Area (JBR 1997a) followed the USACE "Corps of 

Engineers Wetlands Delineation Manual" (USACE 1987). 

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Streamside wetlands form the bulk of the wetlands that were surveyed (JBR 1997a). They are 

typical of Colorado mountain valley wetlands ranging from moist and wet meadows (within 

alluvial deposition areas) to heavily vegetated herbaceous strips (along stream banks). These 

wetland types are typically heavily vegetated herbaceous meadows to moist meadow 

communities because they receive moisture from later subirrigations along the stream channel. 

Specifically, wetlands were delineated in and near the Project Area along Taylor Creek and 

Good Spring Creek, as well as certain tributaries to those streams. Wilson Creek does not 

appear to have been included in this study and although it occurs in the Project Area it has not 

been disturbed by mining activities. Riparian vegetation was mapped along Wilson Creek and is 

described below (JBR 1997). The National Wetlands Inventory (USFWS 2015) is consistent 

with information provided above, showing small wetlands along these streams (as well as along 

Wilson Creek), within and immediately adjacent to the Project Area. As expected, those 

associated with the intermittently flowing Taylor Creek are less extensive than those associated 

with the perennial streams.

On occasion, wetlands developing along the margins of older, more stable stock ponds exhibit 

emergent wetland communities. Two very small stock watering ponds occur in the Project 

Area (Colowyo 2007). Though largely devoid of vegetation, at least one of these at some time 

was associated with a very small amount of wetland vegetation. 

Riparian vegetation has been mapped streamside along Wilson Creek within the Project Area 

(Section 5, T3N, R93W) (Harner and Associates, Inc. 1985). Specifically, it was classified as a 

riparian woodland dominated by boxelder trees. In addition, “meadow” vegetation was 

mapped along Wilson, Taylor, Good Spring, and the West Fork of Good Spring creeks, noting 

that the meadow type varied within this category depending upon moisture and soil 

characteristics. Some vegetation noted to occur within these meadows could denote wetland 

communities (sedge [Carex spp.], cattail [Typha spp.], and bulrush [Schoenoplectus lacustris]), 

however, they were not delineated as part of that investigation. They likely coincided with 

wetlands subsequently delineated by JBR (1997a). Wilson, Taylor, Good Spring, and West Fork 

Good Spring creeks were mapped with riparian corridors as well (Colowyo 2007), though 

these were not continuous. Small wetland communities exist in some of these areas, but were 

not separately delineated. However, along each bank of Wilson Creek, a persistent small 

emergent palustrine emergent wetland community, in the form of a very narrow stringer, was 

noted (Colowyo 2007). Dominant vegetation along this narrow wetland corridor includes: 

Baltic rush (Juncus balticus), broad-leaved cattail (Typha latifolia), spikerush (Eleocharis palustris), 

Nebraska sedge (Carex nebrascensis), redtop (Agrostis alba), and bulrush. 

3.7.2 Waters of the U.S.

WOTUS are defined under 40 CFR 230.3(s) (2004)8 as the following:

1. All waters which are currently used, or were used in the past, or may be susceptible to use in 

interstate or foreign commerce, including all waters which are subject to the ebb and flow of the 

tide;

8 This rule will be changed effective August 28, 2015; however, the new rule will not protect any new types of 

waters that historically have not been protected by the CWA.

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2. All interstate waters including interstate wetlands;

3. All other waters such as intrastate lakes, rivers, streams (including intermittent streams), 

mudflats, sandflats, wetlands, sloughs, prairie potholes, wet meadows, playa lakes, or natural 

ponds, the use, degradation or destruction of which could affect interstate or foreign commerce 

including any such waters: 

i. Which are or could be used by interstate or foreign travelers for recreational or other 

purposes; or

ii. (From which fish or shellfish are or could be taken and sold in interstate or foreign 

commerce; or

iii. Which are used or could be used for industrial purposes by industries in interstate 

commerce;

iv. WOTUS do not include prior converted cropland. Notwithstanding the determination of 

an area’s status as prior converted cropland by any other federal agency, for the 

purposes of the CWA, the final authority regarding CWA jurisdiction remains with EPA.

4. All impoundments of waters otherwise defined as WOTUS under this definition;

5. Tributaries of waters identified in paragraphs (s)(1) through (4) of this section;

6. The territorial sea;

7. Wetlands adjacent to waters (other than waters that are themselves wetlands) identified in 

paragraphs (s)(1) through (6) of this section; waste treatment systems, including treatment 

ponds or lagoons designed to meet the requirements of CWA (other than cooling ponds as 

defined in 40 CFR 423.11(m) which also meet the criteria of this definition) are not WOTUS.

WOTUS include channels that show evidence of conveying flowing water on at least an average 

annual basis and have the presence of a defined bed and banks. While wetlands are a type of 

WOTUS and were reported to the USACE (JBR 1997a), non-wetland WOTUS within the 

Project Area were separately reported to the USACE (JBR 1997b). That study found 

approximately 51 acres of jurisdictional WOTUS associated with Good Spring Creek and 

tributaries, and Taylor Creek. Only 2.12 acres were located inside the disturbance footprint

for PR02.

Dredge and fill activities within jurisdictional areas are regulated by the USACE. If wetlands are 

present adjacent to a WOTUS, USACE jurisdiction extends beyond the ordinary high water 

mark of the waters to the limit of the adjacent wetlands. 

3.8 FISH AND WILDLIFE RESOURCES 

The wildlife habitat located within the Project Area is predominately composed of sagebrush 

and mountain shrub vegetation communities. Other common habitat types include aspen 

woodland, grassland, juniper scrub, and bottomland types found in drainages and basins. Minor 

habitat types that encompass 0.5 percent or less of the Project Area include disturbed areas, 

cultivated land, improved pasture, and wetlands.

3.8.1 Mammals

Many mammal generalist species occur in and around the Project Area. Common predators 

include coyote (Canis latrans), red fox (Vulpes vulpes), mountain lion (Puma concolor), bobcat 

(Lynx rufus), and black bear (Ursus americanus). Medium sized mammals include: porcupine 

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(Erethizon dorsatum), striped skunk (Mephitis mephitis), and American badger (Taxidea taxus). 

Other small mammals that may occur in the Project Area include: desert cottontail (Sylvilagus 

audubonii), mountain cottontail (S. nuttallii), white-tailed jackrabbit (Lepus townsendii), whitetailed prairie dog (Cynomys leucurus), golden-mantled ground squirrel (Spermophilus lateralis), 

northern pocket gopher (Thomomys talpoides), least chipmunk (Tamias minimus), and deer 

mouse (Peromyscus maniculatus) (Colowyo 2012a).

Habitat for bats is present in the Project Area and includes: trees, shrubs, and rocky outcrops. 

While no focused bat surveys have been completed, several species of bats have the potential 

to occur. Those species include: western small footed myotis (Myotis ciliolabrum), little brown 

myotis (M. lucifugus), and silver haired bat (Lasionycteris noctivagans) (Colowyo 2012a).

3.8.2 Big Game

Mule deer (Odocoileus hemionus) and elk (Cervus elephus) are regularly found in the Project Area. 

Aerial surveys for mule deer and elk are conducted annually by CPW. The results from the 

most recent surveys are summarized below, in addition to descriptions of seasonal big game 

habitat within the Project Area. Other big games species that occur in the Project Area include 

pronghorn antelope (Antilocapra americana) and moose (Alces alces).

3.8.2.1 Mule Deer

Mule deer within the Project Area are part of the White River mule deer herd (Data Analysis 

Unit [DAU] 7), which is the largest mule deer herd in Colorado. The total herd population 

was estimated to be 71,380 animals in 2007 and 37,530 in 2014 (CPW 2015a). The herd 

population exhibited an increasing trend from 2001 to 2005. The decrease between 2007 and 

2014 may be due to a series of severe winters and droughts, which affected the area. 

A five-year average of annual aerial winter counts resulted in a range of 184 to 918 mule deer 

using the vicinity around the Project Area during the winter (Colowyo 2007). Based on CPW 

estimates, fewer mule deer winter in the area compared to elk. However, like elk, mule deer 

abundance and distribution in this region can vary dramatically year-to-year depending on the 

severity of the winter (Colowyo 2007 and 2013a).

Four types of mule deer range occur within the Project Area, with three of them being shown 

on Figure 3-7 as all of the Project Area is mule deer summer range. Mule deer winter range is 

located on the north and southeast portions of the Project Area and totals approximately 

2,764.8 acres (52.9 percent of the Project Area). The northern and southeastern portions of 

the Project Area contain approximately 3,061.6 acres (43.0 percent of the Project Area) of 

winter concentration area. Mule deer severe winter range exists on the southeast corner of 

the Project Area and is approximately 1,402.5 acres (19.7 percent of the Project Area). 

Seasonal use of the Project Area is dependent on snow levels, which vary from year to year. 

Unlike elk, mule deer do not concentrate in particular areas when fawning; therefore, no 

production habitat is delineated. 

Mule deer use the area in and around the Project Area year-round, though use of sites in 

winter is dependent on snow depths. South-facing slopes with sagebrush are more likely to be 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 3-40

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used in winter. Also, deer are known to heavily use previously mined areas that have been 

reclaimed as grasslands (Colowyo 2011).

3.8.2.2 Elk

Elk within the Project Area are part of the White River herd (DAU 6) as defined by CPW. The 

population of the White River elk herd has grown steadily beginning in the early 1980s, and 

CPW has been attempting to reduce the herd size. As a result, the herd exhibited a declining 

trend from 2001 to 2005, though the population remained well within the 2005 management 

goal of 32,000 to 39,000 animals (Colowyo 2007). In 2007, the herd was estimated to be 

43,870 animals. In 2014, the total herd population was estimated at 39,900 animals, and 

represents the largest elk herd in Colorado (CPW 2015a). 

Within the general area, winter aerial surveys of elk from 1994 through 1997 found that elk 

populations varied greatly. Populations varied from a high of 1,590 and a low of 259. This 

represents 5.5 and 0.9 percent, respectively, of the total White River herd. This variation is 

based on both snow depths and temperature. In general, most observations of elk during the 

winter are made within the mountain shrub habitat type (Colowyo 2007).

Elk seasonal ranges within the Project Area include: winter concentration areas, production 

areas, and severe winter range (Figure 3-8). CPW data indicates that the entire Project Area 

is both summer and winter range for elk. Winter concentrations areas are located in the 

northern portion of the Project Area and total 1,534.7 acres (21.6 percent of the Project Area). 

Elk production areas are located in the southwest portion of the Project Area and total 1,203.7

acres (16.9 percent of the Project Area). There is also approximately 1,762.7 acres of elk 

severe winter range within the northern portion of the Project Area (24.8 percent of the 

Project Area).

Seasonal use of the Project Area would be dependent on snow levels, which vary from year to 

year. The larger geographic region from the Danforth Hills to the Axial Basin is considered an 

elk migration area. 

Elk are known to heavily use areas of the existing mine that have been reclaimed as grasslands 

throughout most of the year, but they are prevalent in the winter and spring. Elk wallows have 

been noted in most of the dense aspen stands in the area (Cedar Creek 2006).

3.8.2.3 Pronghorn Antelope and Moose

The Project Area occurs within the A-34 unit for pronghorn antelope. In 2014, this unit had an 

estimated population of 330 individuals, and in 2007 there was an estimated 340 animals. This 

is approximately 0.6 percent of the statewide population (CPW 2015a). The Project Area 

contains approximately 909.6 acres of overall range for pronghorn habitat (12.8 percent of the 

Project Area) and 27.0 acres of winter habitat (0.4 percent of the Project Area). Both of these 

habitats occur at the northernmost portion of the Project Area (Figure 3-7).

The Project Area does not occur within any mapped unit for moose. Nor is there any 

designated habitat for this species within the Project Area although they are known to travel 

through the area.

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County Road

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Notes

1: Coordinate System: NAD 1983 UTM Zone 13N

2: Service Layer Credits: Copyright:© 2013 National

Geographic Society, i-cubed

Disclaimer: Figure prepared for OSMRE by Stantec. Stantec assumes no

responsibility for data supplied in electronic format. The recipient

accepts full responsibility for verifying the accuracy and completeness

of the data. The recipient releases Stantec, its officers, employees,

consultants and agents, from any and all claims arising in any way from

the content or provision of the data.

Figure No.

Title

Rio Blanco & Moffat Counties

Colorado

Project Location

Project
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Elk Severe Winter Range

Elk Production Area

County Road

Highway

County Boundary

Project 

Location

Notes

1: Coordinate System: NAD 1983 UTM Zone 13N

2: Service Layer Credits: Copyright:© 2013 National

Geographic Society, i-cubed

Disclaimer: Figure prepared for OSMRE by Stantec. Stantec assumes no

responsibility for data supplied in electronic format. The recipient

accepts full responsibility for verifying the accuracy and completeness

of the data. The recipient releases Stantec, its officers, employees,

consultants and agents, from any and all claims arising in any way from

the content or provision of the data.

Figure No.

Title

Rio Blanco & Moffat Counties

Colorado

Project Location

Project
Chapter 3 – Affected Environment

3.8.3 Migratory Birds

The Migratory Bird Treaty Act (MBTA) (916 USC 703-711) provides protection for 1,007 

species of native migratory birds. The Act makes it illegal for anyone to take, possess, import, 

export, transport, sell, purchase, barter, or offer for sale any migratory bird, or the parts, nests, 

or eggs of such a bird except under the terms of a valid permit issued pursuant to Federal 

regulations. The USFWS Birds of Conservation Concern (BCC) document lists a total of 24

species that are of the highest priority for the Northern Rockies and Southern 

Rockies/Colorado Plateau Bird Conservation Regions and that may occur in the Project Area 

(USFWS 2008). The purpose of the BCC list is to identify those species in greatest need of 

conservation action, outside of those species already listed by the USFWS as threatened or 

endangered. All 24 species on the BCC list have been, or could be, observed in or near the 

Project Area (Table 3.8-1).

Table 3.8-1 BCC Species that have the Potential to Occur in the Project Area

Common Name Scientific Name Habitat Potential to 

Occur

American Bittern Botaurus lentiginosus Freshwater wetlands dominated 

by tall dense vegetation Limited

Bald Eagle1 Haliaeetus leucocephalus

Breeds near reservoirs and 

rivers. Winters in semideserts 

and grasslands

Limited

Black Swift Cypseloides niger Cliffs, bare rock Yes

Brewer’s Sparrow1 Spizella breweri Shrublands with average canopy 

cover over 1.5 meters Yes

Brown-capped Rosyfinch Leucosticte australis Open areas, fields and brushy 

areas

Yes

Burrowing Owl

1 Athene cunicularia

Grasslands with prairie dogs 

colonies or other fossorial 

mammals

Yes

Cassin’s Finch Carpodacus cassinii Open coniferous forests and in 

deciduous woodlands Limited

Ferruginous Hawk1 Buteo regalis Grasslands, semi-desert 

shrublands Yes

Fox Sparrow Passerella liaca Dense thickets in coniferous and 

mixed woodlands Limited

Golden Eagle Aquila chrysaetos Open and semi-open prairies, 

sagebrush, and barren areas Yes

Greater Sage-grouse1 Centrocercus urophasianus Sagebrush Yes

Juniper Titmouse Baeolophus ridgwayi Pinyon juniper woodlands Limited

Lewis’s Woodpecker Melanerpes lewis Open forests and woodland Limited

Loggerhead Shrike Lanius ludovicianus Open areas with scattered trees 

and shrubs Yes

Olive-sided Flycatcher Contopus cooperi Forests and woodland Limited

Peregrine Falcon1 Falco peregrinus Open spaces with cliffs and bluffs 

overlooking bodies of water Yes

Pinyon Jay Gymnorhinus cyanocephalus Pinyon-juniper woodland Limited

Prairie Falcon Falco mexicanus Open areas, steppe, plains, and 

prairies Yes

Sage Thrasher Oreoscoptes montanus Sagebrush plains in arid and semiarid areas Yes

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Common Name Scientific Name Habitat Potential to 

Occur

Short-eared Owl Asio flammeus Winters communally in sheltered 

areas near feeding sites Yes

Swainson’s Hawk Buteo swainsoni Savanna, open woodlands, and 

cultivated lands Yes

Veery Catharus fuscescens Swampy forests with shrubby 

understory

Limited

Williamson’s Sapsucker Sphyrapicus thyroideus

Middle to high elevation 

coniferous forests. Mixed 

deciduous-coniferous forests 

with aspen

Limited

Willow Flycatcher Empidonx traillii Thickets of willow associated 

with wet areas. Limited

1 Discussed in detail in Section 3.9

3.8.4 Raptors

Raptor surveys were conducted in the Project Area between 1984 and 1997 as well as 2006 

through 2008. In those surveys, the following species were identified within or near the Project 

Area: Cooper's hawk (Accipiter cooperii), golden eagle, great horned owl (Bubo virginianus), longeared owl (Asio otus), prairie falcon, red-tailed hawk (Buteo jamaicensis), and turkey vulture 

(Cathartes aura). Other raptors that have the potential to occur include sharp-shinned hawk 

(Accipiter striatus), American kestrel (Falco sparverius), northern harrier (Circus cyaneus), and 

Swainson's hawk (Colowyo 2007 and 2013a).

Bald and golden eagles are protected under MBTA and the Bald and Golden Eagle Protection 

Act. CPW recommends no surface occupancy (beyond that which historically occurred in the 

area) within a 1⁄4 mile (0.4 km) radius of active golden eagle nests. CPW also recommends 

seasonal restriction to human encroachment within a 1⁄2 mile (0.8 km) radius of active bald 

eagle nests from October 15 through July 31 and from December 15 through July 15 for active 

golden eagle nests. While no nesting habitat for these species occurs within the Project Area, 

both bald and golden eagles may forage in the area.

Nesting habitat for raptors is present throughout the Project Area and surrounding area. The 

most common areas for raptor nesting occur in rocky outcrops and trees along the drainages in 

the area. Additionally, the aspen forests located south of the Project Area represent suitable 

nesting habitat for raptor species. The majority of the Project Area is classified as sagebrush or 

mountain shrub vegetation communities. These areas are likely used as foraging areas for the 

various raptor species. The number of occupied raptor nests within the entire Colowyo Mine 

boundary have ranged between six in 2007 (Cooper's hawk, golden eagle, and red-tailed hawk) 

to 12 in 2006 (Cooper's hawk, golden eagle, great horned owl, long-eared owl, red-tailed hawk, 

and turkey vulture). The number of unoccupied nests have ranged between 56 (2007) and 80 

(2008) (Cedar Creek 2011). A total of 10 nests have been identified within the Project Area

and include three Cooper’s hawks (two active, one inactive) and three red-tail nests (all active)

and four unknown/inactive nests (Colowyo 2007). 

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3.8.5 Reptiles and Amphibians

The Project Area and surrounding area have an estimated seven reptile and four amphibian 

species that may be present. Common reptiles that may be found include the northern 

sagebrush lizard (Sceloporus graciosus), wandering garter snake (Thamnophis elegalas vagrans), and 

western rattlesnake (Crotalus oreganus). Amphibian species that have the potential to occur 

include the boreal chorus frog (Pseudacris triseriat maculata) and the northern leopard frog (Rana 

pipiens) (Colowyo 2007). 

3.8.6 Fish

Within the Project Area, the only perennially flowing stream is Wilson Creek. Forming the 

boundary of the Project Area, Good Spring Creek, which is also perennial, is located to the 

southeast along State Highway 13. Good Spring Creek has been identified by CPW as a nonfishery stream although it is assumed that species such as black bullheads (Ameiurus melas), 

creek chubs (Semotilus atromaculatus), flannelmouth (Catostomus latipinnis), white suckers 

(Catostomus commersonii), flathead minnows (Pimephales promelas), and red shiners (Cyprinella 

lutrensis) are likely to be present. While Wilson Creek has not been classified by CPW, it is 

assumed that it contains similar species as Good Spring Creek (Colowyo 2007 and 2012a). The 

Yampa River is located approximately 7 miles (11 km) north of the mine boundary. Fish 

present in the Yampa River are discussed in Section 3.9.1.

3.9 SPECIAL STATUS SPECIES

Several sources of information were searched to identify sensitive species that have the 

potential to occur in the Project Area: the USFWS Federally Listed Endangered Species for 

Colorado (USFWS 2015) for federally listed species, Colorado Natural Heritage Program's

(CNHP) Species Tracking Lists (CNHP 2015) for state and BLM sensitive species, consultations 

with local BLM and CPW resource specialists, and the Biological Assessment and resulting 

Biological Opinion for PR02 as approved in 2007. Table 3.9-1 lists the federal, state, and BLM 

sensitive species that are recorded for Moffat and Rio Blanco counties.

Table 3.9-1 Federal, State, and BLM Sensitive Species in Moffat and Rio Blanco 

Counties

Group Common 

Name

Scientific 

Name

Federal 

Status State Status BLM Sensitive

Boreal toad Anaxyrus boreas SE Yes

Amphibians Northern 

leopard frog Lithobates pipiens SC Yes

Great Basin 

spadefoot Spea intermontana Yes

Mexican spotted 

owl1 Strix occidentalis Threatened SE

Birds Yellow-billed 

cuckoo1

Coccyzus 

americanus Threatened SC

Ferruginous 

hawk Buteo regalis SC Yes

Greater sagegrouseCentrocercus 

urophasianus Candidate SC Yes

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Group Common 

Name

Scientific 

Name

Federal 

Status State Status BLM Sensitive

Mountain plover Charadrius 

montanus

SC Yes

Greater sandhill 

crane

Grus canadensis 

tabida SC

Bald eagle1, 2 Haliaeetus 

leucocephalus SC Yes

Birds Long-billed 

curlew

Numenius 

americanus SC Yes

Columbian 

sharp-tailed 

grouse

Tympanuchus 

phasianellus 

columbianus

SC Yes

Northern 

Goshawk Accipter gentilis Yes

Burrowing owl Athene cunicularia ST Yes

American 

Peregrine Falcon

Falco peregrinus 

anatum

SC Yes

White faced ibis Plegadis chihi Yes

American white 

pelican

Pelecanus 

erythrorhynchos Yes

Brewer's 

sparrow Spizella berweri Yes

Bonytail

1 Gila elegans Endangered SE

Humpback chub1 Gila cypha Endangered ST

Roundtail chub Gila robusta SC Yes

Fish Colorado River 

cutthroat trout

Oncorhynchus clarkii 

pleuriticus SC Yes

Colorado 

pikeminnow1 Ptychocheilus lucius Endangered ST

Razorback 

sucker1 Xyrauchen texanus Endangered SE

Bluehead sucker Catostomus 

discobolus Yes

Flannelmouth 

sucker

Catostomas 

latipinnis Yes

Mountain sucker Catostomas 

platyrhychus SC Yes

Canada lynx1 Lynx canadensis Threatened SE

White-tailed 

prairie dog Cynomys leucurus Yes

Mammals Spotted bat Euderma 

maculatum Yes

Swift Fox Vulpes velox SC Yes

Black-footed 

ferret Mustela nigrips Endangered SE

Ute Ladies’-

tresses Spiranthes Diluvalis Threatened

Plants

Dudley Bluffs 

bladderpod1, 2 Lesquerella congesta

Graham 

beardtongue1, 2 Penstemon Grahamii

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Group Common 

Name

Scientific 

Name

Federal 

Status State Status BLM Sensitive

Plants White River 

beardtongue1, 2

Penstemon scariosus 

var albifluvis

SE - State endangered

ST - State threatened

SC - State species of concern 1 Previously consulted under Section 7 of the ESA 2 Listed under ESA in 2006 but has since been removed from the ESA.

3.9.1 Threatened, Endangered, and Candidate Species

As required by Section 7 of the ESA, OSMRE conducted formal consultation with the USFWS 

on August 26, 2006 to determine the potential effects of the Project on threatened and 

endangered species. The resulting Biological Opinion from the USFWS issued on November 6, 

2006 (Appendix D) stated that the Proposed Action would have no effect on the following 

species: black-footed ferret, Mexican spotted owl, Dudley Bluffs bladderpod, Dudley Bluffs 

twinpod, western yellow-billed cuckoo, Graham beardtongue and the White River 

beardtongue. No circumstances have changed regarding PR02 that would alter these 

conclusions; as such, these species will not be discussed further with the exception of the yellowbilled cuckoo. The 2007 Biological Opinion also stated that the project may affect but would not 

adversely affect the Canada lynx and bald eagle. Additionally, the Graham beardtongue, White 

River beardtongue and bald eagle have been removed from the ESA list between 2007 and 

2015. The Ute ladies-tresses was added to the list during the same time period as a threatened 

species and the greater sage-grouse (GSG) was added as a candidate species. While the lynx 

was originally included in consultation, it is no longer included on the USFWS list of species in 

the area. Therefore, it is not included in this discussion. Re-initiation of Section 7 consultation 

with the USFWS has been completed and includes the Colorado River fish species, the Ute ladies’-

tresses, which was not listed at the time of the previous consultation, and the western yellowbilled cuckoo.

3.9.1.1 Colorado River Fish 

Four species of fish listed as endangered under the ESA are commonly referred to as the 

Colorado River fish and include the Colorado pikeminnow, razorback sucker, humpback chub,

and bonytail. They are historically found in the Colorado River and its tributaries, including the 

Yampa River. Information on these four species is summarized from the biological assessment 

completed for PR02 in 2006 with a final biological opinion issued in 2007, and from the formal 

consultation conducted in 2012 for the Collom expansion area submitted in PR03 (OSMRE 2006 

and 2012).

The Colorado pikeminnow is endemic to the Colorado River basin, where it was once 

widespread and abundant in warm-water rivers and tributaries. Wild populations of Colorado 

pikeminnow are now found only in the upper basin of the Colorado River (above Lake Powell). 

Three wild populations of Colorado pikeminnow are found in 1,090 miles (1,754 km) of 

riverine habitat in the Green River, upper Colorado River, and San Juan River subbasins. It 

thrives in swift flowing muddy rivers with quiet, warm backwaters and is primarily piscivorous, 

but smaller individuals also eat insects and other invertebrates. These fish spawn between late 

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June and early September and when they are five to six years old and at least 16 inches long. 

Spawning occurs over riffle areas with gravel or cobble substrate. The eggs are randomly 

splayed onto the bottom and usually hatch in less than one week.

The razorback sucker is found in deep clear to turbid waters of large rivers and some 

reservoirs over mud, sand, or gravel, and like most suckers, feeds on both plant and animal 

matter. Razorback suckers can spawn as early as age three or four, when they are 14 or more 

inches long. Breeding males turn black up the lateral line, with brilliant orange extending across 

the belly. Depending on water temperature, spawning can take place as early as November or 

as late as June. In the upper Colorado River basin, razorbacks typically spawn between midApril and mid-June.

Adult humpback chubs are dark on top and light below and fins may have yellow-orange 

pigment near the base. Adults usually range from 12 to 16 inches long and weigh 0.75 to 2 

pounds. This species historically occurred in the mainstream Colorado River in slower eddies 

and pools downstream below Hoover Dam; however, present populations are restricted to 

areas in, and upstream, of the Grand Canyon.

The bonytail is a highly streamlined fish often appearing dark in clear water and pale in more 

turbid waters. It prefers eddies and pools and is not often found in swift currents. Adults of 

seven years of age can reach 14 inches long and weigh more than one pound. Found 

historically throughout the Colorado River drainage, in recent years bonytails have only been 

taken from the Green River in Utah and lakes Havasu and Mohave.

The nearest critical habitat for the four Colorado River fish species is found within the Yampa 

River (Figure 3-9). 

In relation to the Project Area, critical habitat for the Colorado pikeminnow occurs approximately 11 

miles (18 km) north. For the razorback sucker, critical habitat is 30 miles (48 km) northwest of the 

Project Area. For the bonytail and humpback chub, critical habitat is designated within Dinosaur 

National Monument 37 miles (60 km) northwest of the Project Area. These species do not and are 

not likely to occur within the Project Area given the lack of suitable habitat (i.e., perennial 

rivers or streams).

A Recovery Implementation Program for Endangered Fish Species in the Upper Colorado River 

Basin was initialed on January 22, 1988. The Recovery Program was intended to be the 

reasonable and prudent alternative for individual projects to avoid the likelihood of jeopardy to 

the endangered fishes from impacts of depletions to the Upper Colorado River Basin. In order 

to further define and clarify the process in the Recovery Program, a Section 7 agreement was 

implemented on October 15, 1993 by the Recovery Program participants. lncorporated into 

this agreement is a Recovery Implementation Program Recovery Action Plan (RIPRAP) which 

identifies actions currently believed to be required to recover the endangered fishes in the 

most expeditious manner.

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JamesCreek

Little Creek

ElkhornCreek

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River

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Colorado River Fish Habitat

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Location

Notes

1: Coordinate System: NAD 1983 UTM Zone 13N

2: Service Layer Credits: Content may not reflect National

Geographic's current map policy. Sources: National

Geographic, Esri, DeLorme, HERE, UNEP-WCMC, USGS, NASA,

ESA, METI, NRCAN, GEBCO, NOAA, increment P Corp.

Disclaimer: Figure prepared for OSMRE by Stantec. Stantec assumes no

responsibility for data supplied in electronic format. The recipient

accepts full responsibility for verifying the accuracy and completeness

of the data. The recipient releases Stantec, its officers, employees,

consultants and agents, from any and all claims arising in any way from

the content or provision of the data.

Figure No.

Title

Rio Blanco & Moffat Counties

Colorado

Project Location

Project
Chapter 3 – Affected Environment

On January 10, 2005, the USFWS issued a final programmatic biological opinion (PBO) on the 

Management Plan for Endangered Fishes in the Yampa River Basin9 (USFWS 2005). The USFWS

has determined that projects that fit under the umbrella of the Yampa River PBO would avoid 

the likelihood of jeopardy and/or adverse modification of critical habitat for depletion impacts

(USFWS 2005). The Yampa River PBO states that in order for actions to fall within the 

umbrella of the PBO and rely on the RIPRAP to offset its depletion, the following criteria must 

be met.

l. A Recovery Agreement must be offered and signed prior to conclusion of Section 7 

consultation.

2. A fee to fund recovery actions will be submitted as described in the proposed action for 

new depletion projects greater than 100 acre-feet/year. The 2007 fee is $17.24 per 

acre-foot and is adjusted each year for inflation.

3. Re-initiation stipulations will be included in all individual consultations under the umbrella 

of this programmatic.

4. USFWS and project proponents will request that discretionary federal control be 

retained for all consultations under this programmatic.

3.9.1.2 Greater Sage-Grouse

The GSG is the largest grouse in North America. Males often weigh in excess of four to five 

pounds and hens weigh two to three pounds. Immature birds (less than one year) can be 

distinguished from adults by their light yellowish green toes (adults have dark green toes). The 

birds are found at elevations ranging between 4,000 feet to over 9,000 feet and are highly 

dependent on sagebrush for cover and food.

The largest number of GSG in Colorado occurs in the northwestern portion of the state, with 

Moffat County supporting the majority of breeding populations within the region (Northwest 

Colorado Greater Sage-Grouse Working Group [GSGWG] 2008). The population in 

northwest Colorado exhibited an increasing population trend from 1997 to 2005; however, from

2007 to 2010 the population was generally steady with some slight declines in numbers at some leks. 

Despite this small regional decline, populations in Colorado have been generally increasing for the 

past 17 years and breeding populations have not declined for the last 39 years (BLM 2015). 

GSG use of reclaimed mine areas in Colorado has been slow to develop because of the species 

reliance on big sagebrush, which can be difficult to establish through reclamation efforts 

(GSGWG 2008).

Within the Project Area there is 156.9 acres of GSG brooding habitat (2.2 percent of the 

Project Area), 955.4 acres of winter habitat (13.4 percent of the Project Area), and 5,424.0 

acres of production habitat (76.2 percent of the Project Area) (CPW 2008). In addition to 

these habitat designations, approximately 655.1 acres of the Project Area (9.2 percent) has 

been designated as Priority Habitat Management Area (PHMA) and 4,776.6 acres (65.4 percent) 

is designated as General Habitat Management Area (GHMA) (Figure 3-10) (CPW 2011). 

PHMA areas are defined as "areas that have been identified as having the highest conservation 

9 http://www.coloradoriverrecovery.org/documents-publications/technical-reports/isf/yampa/YampaPlan.pdf

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 3-51

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value to maintaining sustainable GSG populations; including, breeding, late brood-rearing and

winter concentrations areas." GHMA areas are defined as, "areas of seasonal or year-round 

habitat outside of priority habitat" (BLM 2011). It should be noted that at the time of the 

originally submittal and approval of PR02, PHMA and GHMA were not mapped for GSG.

While no leks occur within the Project Area, a total of seven GSG leks have been documented 

within 4 miles (6 km) of the Project Area. Of these seven, four are located within the current

mine permit boundary (leks SG1, SG3, SG4, and SG7) and three are outside the boundary (leks 

SG5, SG12, and Morgan 3). However, none of these leks occur within the PR02 permit boundary. In 

2014, four of the leks were active (i.e., at least one GSG present within the last five years) and 

three were inactive. Table 3.9-2 depicts the seven leks, their distance (in miles) to the Project 

Area, and their status between 2010 and 2014 (survey years).

Table 3.9-2 GSG Lek Counts Near the Project Area

Lek Name

Distance 

to Project 

Area 

(miles)

Males

2010

Males

2011

Males

2012

Males

2013

Males 

2014

SG1 0.2 0 0 0 0 No Count

SG3 2.1 0 0 0 0 0

SG4 2.8 9 15 27 26 39

SG7 3.7 5 4 0 0 5

SG5/Axial Basin 1.5 0 0 0 0 0

SG12/Gossard 1.7 3 4 0 0 12

Morgan 3 2.7 5 7 1 8 51

Source: CPW 2013 and K. McKinstry, personal communication, July 31, 2014.

The Project Area and the Colowyo Mine as a whole are located within the Axial Basin 

population of GSG. This population is one of the most studied populations within Colorado. 

From 2001 to 2008 a number of studies were conducted in the Axial Basin. These studies 

followed up to 280 radio-collared GSG to determine their locations and habitat use. Analysis 

of these data showed that GSG occur primarily north and west of the Project Area and west of 

County Road 51 and do not generally use the area in or around the Project Area (CPW, 

personal communication, February 20, 2014).

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County Road

Highway

County Boundary

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Location

Notes

1: Coordinate System: NAD 1983 UTM Zone 13N

2: Service Layer Credits: Copyright:© 2013 National

Geographic Society, i-cubed

Disclaimer: Figure prepared for OSMRE by Stantec. Stantec assumes no

responsibility for data supplied in electronic format. The recipient

accepts full responsibility for verifying the accuracy and completeness

of the data. The recipient releases Stantec, its officers, employees,

consultants and agents, from any and all claims arising in any way from

the content or provision of the data.

Figure No.

Title

Rio Blanco & Moffat Counties

Colorado

Project Location

Project
Chapter 3 – Affected Environment

3.9.1.3 Ute Ladies’-tresses

The Ute ladies'-tresses orchid is a perennial, terrestrial orchid with stems 8 to 20 inches tall, 

arising from tuberously thickened roots. It blooms from late July through August.

Habitat for the Ute ladies'-tresses has expanded since the 1992 listing, which includes moist

meadows associated with perennial stream terraces, floodplains, and oxbows at elevations

between 4,300 to 6,850 feet; seasonally flooded river terraces, sub-irrigated or spring-fed

abandoned stream channels and valleys, and lakeshores; and areas along irrigation canals, berms,

levees, irrigated meadows, excavated gravel pits, roadside barrow pits, reservoirs, and other

human-modified wetlands. Over one-third of all known Ute ladies'-tresses populations are 

found on alluvial banks, point bars, floodplains, or ox-bows associated with perennial streams.

Colorado populations of Ute ladies'-tresses orchids may be found within north-central and

central Colorado and the upper Colorado River basin, particularly in the Uinta Basin. There 

are no known populations of this species occurring within or near the Project Area. The 

nearest known population is located in northwestern Moffat County, approximately 70 miles

(113 km) from the mine.

Due to the lack of suitable habitat in the Project Area and the distance to the nearest known 

population, this species will not be discussed further.

3.9.1.4 Western Yellow-billed Cuckoo

The western yellow-billed cuckoo is a medium-sized bird about 12 inches (30 cm) in length, and 

weighing about 2 ounces (57 grams [g]). The species has a slender, long-tailed profile, with a fairly 

stout and slightly downcurved bill, which is blue-black with yellow on the basal half of the lower 

mandible. Plumage is grayish-brown above and white below, with rufous primary flight feathers

(USFWS 2011a).

Western yellow-billed cuckoos breed in large blocks of riparian habitats, particularly woodlands with 

cottonwoods (Populus fremontii) and willows (Salix spp.). Dense understory foliage appears to be an 

important factor in nest site selection, while cottonwood trees are an important foraging habitat in 

areas where the species has been studied in California. In the Lower Colorado River, this species 

occupies riparian areas that have higher canopies, denser cover in the upper layers of the canopy, and 

sparser shrub layers when compared to unoccupied sites. Although this species is generally associated 

with breeding and nesting in large wooded riparian areas dominated by cottonwood trees, they have 

been documented nesting in salt cedar between Albuquerque and Elephant Butte Reservoir and along 

the Pecos River in southeastern New Mexico. At the landscape level, the amount of cottonwood-willowdominated vegetation cover in the landscape and the width of riparian habitat appeared to influence 

cuckoo distribution and abundance (USFWS 2011a).

Nesting sites are generally selected in locations near water. Clutch size is usually two or three eggs, 

and development of the young is very rapid, with a breeding cycle of 17 days from egg-laying to fledging 

of young. Although yellow-billed cuckoos usually raise their own young, they are facultative brood 

parasites, occasionally laying eggs in the nests of other yellow-billed cuckoos or of other bird species 

(USFWS 2011a). Currently it is not known if yellow-billed cuckoos show breeding site fidelity. In some 

instances, individuals in Arizona and California returned to the same sites in successive years. 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 3-54

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Conversely, dramatic fluctuations in breeding pair numbers at long-term study sites indicate that pairs of 

cuckoos will use different breeding areas (78 FR 61621).

Diet of this species consists of caterpillars, lepidopterans, and is often supplemented with beetles, ants, 

and spiders. They also take advantage of the annual outbreaks of cicadas, katydids, and crickets, and 

will forage for small frogs and lizards. In summer and fall, cuckoos forage on small wild fruits, including 

elderberries, blackberries, and wild grapes. In winter, fruit and seeds become a larger part of the diet.

On October 3, 2014, the Western U.S. Distinct Population Segment of yellow-billed cuckoo was 

formally listed as a threatened species under the ESA (79 FR 59991). To date, the last known sighting 

of the cuckoo along the Yampa River occurred in 2008 and was within the proposed critical habitat. 

No information is available to indicate if the birds observed were nesting in the area or in the process of 

migration (C. Clayton, personal communication, July 28, 2015).

Critical habitat for the yellow-billed cuckoo was proposed in 2014 and includes a portion of the riparian 

area around the Yampa River between Craig, CO and Hayden, CO (79 FR 48548). The critical habitat 

is located approximately 16 miles (26 km) northeast of the Colowyo Mine and 1.3 miles (2 km) north 

of the Craig Generating Station.

3.9.2 State Listed and BLM Sensitive Species

Colorado state species of concern are those species identified by CPW as declining or appear 

to be in need of conservation. BLM sensitive species are those species that require special 

management consideration to avoid potential future listing under the ESA.

3.9.2.1 Boreal Toad

The boreal toad is a state-endangered amphibian species that is typically found in spruce-fir and 

aspen forests. Within these habitats, breeding is restricted to beaver ponds, lakes, streams, 

marshes, wet meadows, and bogs with sunny exposure and shallow water (BLM 2006). Given 

the lack of suitable habitat within the Project Area and lack of reported sightings in the area, it 

is unlikely that this species would occur. Therefore, it will not be discussed further.

3.9.2.2 Northern Leopard Frog

The northern leopard frog is a state species of special concern as well as listed by the BLM as a 

sensitive species. This species is found in heavily vegetated areas in a variety of aquatic habitats, 

including wet meadows, banks and shallows of marshes, ponds, lakes, reservoirs, streams and 

irrigation ditches (BLM 2006). Given the lack of suitable habitat within the Project Area and the 

lack of reported sightings, it is unlikely that this would occur. Therefore, it will not be 

discussed further.

3.9.2.3 Great Basin Spadefoot

This species is listed by the BLM as sensitive. It is found in pinyon-juniper woodlands, sagebrush 

flats, and semidesert shrublands. It commonly uses the bottom of rocky canyons, broad dry 

basins, and stream floodplains (BLM 2006). This species has the potential to occur within the 

Project Area, based on the habitat types that are found within the Project Area; however, there 

have been no reported sightings in the Project Area.

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3.9.2.4 Ferruginous Hawk

Ferruginous hawks are listed as a species of concern in Colorado as well as a BLM sensitive 

species. It breeds in grasslands, semidesert shrublands, and the ecotone between shrublands 

and pinyon-juniper woodlands. Nests are found on elevated sites, such as rock outcrops, 

power poles, or isolated trees. Winter concentrations are found around prairie dog towns 

(BLM 2006). While the CNHP lists this species as rare in Moffat and Rio Blanco counties, there 

is suitable habitat present within the Project Area for this species to occur. There have been 

no reported sightings in the Project Area.

3.9.2.5 Mountain Plover

The mountain plover is listed as a species of concern in Colorado as well as a BLM sensitive 

species. It breeds in short, sparse grasslands, rangeland, and agriculture fields, such as where 

grazed by livestock or prairie dogs (BLM 2006). Given the limited amount of this type of 

habitat in the Project Area, the probability for this species to occur is low. There have been no 

reported sightings in the Project Area.

3.9.2.6 Greater Sandhill Crane

This species is listed as a species of concern for Colorado. The greater sandhill crane breeds in 

marshes, wet grasslands, and near beaver ponds or natural ponds lined with willow or aspens. 

Migrating birds forage along mudflats on reservoirs, moist meadows, and agricultural areas 

(BLM 2006). Given the lack of suitable habitat within the Project Area, it is unlikely that this 

would occur. Therefore, it will not be discussed further.

3.9.2.7 Bald Eagle

The bald eagle was previously listed under the ESA but was delisted in 2007. It is currently 

listed as a species of concern in Colorado as well as a BLM sensitive species. The bald eagle 

breeds near reservoirs and rivers. In winter they may occur locally in semideserts and 

grasslands, especially near prairie dog colonies. It is unlikely that the bald eagle would occur in 

the Project Area; however, one pair was observed in 2005 near the Project Area (BLM 2006).

3.9.2.8 Long-billed Curlew

The long-billed curlew is currently listed as a species of concern for Colorado as well as a BLM 

sensitive species. It breeds in short, sparse grasslands, or more rarely in wheat fields or fallow 

fields. Most nesting occurs close to standing water. It may use shorelines, meadows, and fields 

during migration (BLM 2006). Given the lack of suitable habitat within the Project Area, it is 

unlikely that this would occur. Therefore, it will not be discussed further.

3.9.2.9 Columbian Sharp-tailed Grouse

The Columbian sharp-tailed grouse is currently listed as a species of concern for Colorado as 

well as a BLM sensitive species. It is found where deciduous shrubs (Gamble oak and 

serviceberry) are interspersed with bunch grasses, sagebrush, aspen, irrigated meadows, wheat 

fields, or alfalfa fields. Display grounds are on knolls or ridges (BLM 2006). This species is 

known to occur within the Project Area although no leks are known to occur within the 

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Project Area. However, six leks are located within 1.25 miles (2 km) of the Project Area 

boundary (Table 3.9-3). In addition to known lek locations, the entire Project Area is mapped 

as Columbian sharp-tail grouse range. There is also approximately 1,357.6 acres of production 

habitat and 3,713.2 acres of winter range for this species within the Project Area (19.1 and 52.2

percent of the Project Area, respectively).

Table 3.9-3 Columbian Sharp-tailed Grouse Lek Counts in the Vicinity of the 

Project Area

Lek Name

Distance to 

Project 

Area 

(Miles)

2006 Male 

Count

2007 Male 

Count

2008 Male 

Count

2011 Male 

Count

Jubb 1.1 Inactive Inactive Inactive Inactive

Jubb 2 1.0 11 7 1 Inactive

Jubb 3 1.0 No Count No Count No Count 10+

Jubb 4 0.9 No Count No Count No Count 5

Wilson 0.4 Inactive Inactive Inactive Inactive

Wilson 2 0.3 12 7 11 31+

3.9.2.10 Northern Goshawk

The northern goshawk is currently listed as a BLM sensitive species. This species is found in 

boreal and temperate forests. Nesting tends to occur in mature coniferous forests in the 

West. This species is not likely to nest or forage in or near the Project Area due to the lack of 

forested areas. Therefore, this species will not be discussed further.

3.9.2.11 Burrowing Owl

The burrowing owl is currently listed as a BLM sensitive species and threatened in Colorado. 

This species is commonly found in prairie dog towns throughout Colorado. It requires either 

prairie dog, badger, or other fossorial mammal burrows for nesting. This species has the 

potential to occur within the Project Area; however, there have been no reported sightings in 

the Project Area. 

3.9.2.12 American Peregrine Falcon

The peregrine falcon is a state species of concern as well as a BLM sensitive species. This 

species is found in open spaces associated with cliffs and bluffs overlooking rivers and open 

bodies of water. Habitat does exist and this species may occur; however, there have been no 

reported sightings in the Project Area. 

3.9.2.13 White-faced Ibis

The white faced ibis is currently listed as a BLM sensitive species in Colorado. This species 

primarily inhabits freshwater wetlands, particularly cattail and bulrush marshes. It feeds in 

flooded hay meadows, agricultural fields and estuarine wetlands. Given the lack of suitable 

habitat within the Project Area, it is unlikely that this species would occur. Therefore, it will 

not be discussed further.

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3.9.2.14 American White Pelican

The American white pelican is a BLM sensitive species in Colorado. This species is most 

commonly seen foraging at open bodies of water, shallow marshes, and rivers. While some 

suitable habitat exists in the vicinity of the Project Area, none actually occurs within the Project 

Area; therefore, it is unlikely that this species will occur in the Project Area, and will not be 

discussed further.

3.9.2.15 Brewer's Sparrow

The Brewer’s sparrow is a BLM sensitive species in Colorado. It forages and nests in 

shrublands with an average canopy height greater than 1.5 meters. It is most commonly found 

in landscapes dominated by big sagebrush. Abundant habitat exists both within and in the 

vicinity of the Project Area; however, there have been no reported sightings in the Project 

Area.

3.9.2.16 Roundtail Chub

The roundtail chub is currently listed as a species of concern for Colorado as well as a BLM 

sensitive species. It occurs in large rivers with quiet water adjacent to fast moving water. The 

largest populations are found in habitats with a wide range of annual flows (i.e. high peaks and 

low base flows) and high sediment loads (BLM 2006). This species may occur in Wilson Creek 

within the Project Area; however, there have been no reported sightings in the Project Area.

3.9.2.17 Colorado River Cutthroat Trout

The Colorado River cutthroat trout is a subspecies of cutthroat trout and is currently listed as 

a species of concern for Colorado as well as a BLM sensitive species. It is found in cool, clear 

water of high elevation streams and lakes (BLM 2006). While there is perennial water in the 

Project Area, none of the streams contain habitat for this species. Therefore, it will not be 

discussed further.

3.9.2.18 Bluehead Sucker, Flannelmouth Sucker, and Mountain Sucker

The bluehead, flannelmouth, and mountain suckers are all BLM sensitive species in Colorado, 

and the mountain sucker is a state species of concern. These species are found in the river 

basins of northwest Colorado including the Yampa and White River basins. They are typically 

found in rivers and streams with gravel, sand, and mud bottoms. These species may occur in 

Wilson Creek within the Project Area; however, there have been no reported sightings of 

these species in the Project Area.

3.9.2.19 Townsend's Big-eared Bat

The Townsend's big-eared bat is currently listed as a species of concern in Colorado as well as 

a BLM sensitive species. It roosts in mines, caves, and structures. It forages on insects over 

adjacent pinyon-juniper woodlands, open montane forests, and semidesert shrublands (BLM 

2006). While the availability of roosting habitat is unknown in the Project Area, this species 

may forage in the area.

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3.9.2.20 White-tailed Prairie Dog

The white-tailed prairie dog is a BLM sensitive species in Colorado. This species is found in 

open shrublands, semidesert grasslands, and mountain valleys in northwestern Colorado. This 

species is known to occur within the vicinity of the Project Area.

3.9.2.21 Swift Fox

The swift fox is listed as a BLM sensitive species in Colorado and a state species of concern. 

This species is most commonly found in shortgrass and midgrass prairies in eastern Colorado. 

Habitat for this species exists within and near the Project Area, although there are no known 

sightings of this species in the vicinity. 

3.10 CULTURAL AND HISTORIC RESOURCES

Cultural resources are defined as any definite location of past human activity identifiable 

through field survey, historical documentation, and/or oral evidence. Cultural resources 

include archaeological or architectural sites, structures, or places, and places of traditional 

cultural or religious importance to specified groups whether or not represented by physical 

remains. Cultural resources have many values and provide data regarding past technologies, 

settlement patterns, subsistence strategies, and many other aspects of history. 

The Project is considered an undertaking subject to compliance with Section 106 of the NHPA. 

The NHPA, as amended, and its implementing regulations (36 CFR 60 and 800) require that 

federal agencies take into account the effects of their undertakings on important archaeological 

and historic sites in the area of potential affect (APE). In the terminology of NHPA, important 

sites are those that are determined to be eligible to the National Register of Historic Places 

(NRHP). Some sites require more information to determine eligibility; therefore they are 

designated as unevaluated or “need data” sites. In the case of archaeological sites, this is usually 

provided through test excavation. “Needs data” sites are managed as though they are eligible 

for the NRHP until further evaluated. If these “need data” sites are to be affected by the 

undertaking, test excavation determines if salvage excavation is necessary or if no further work 

is needed.

Under NEPA, federal agencies have broad responsibilities to disclose the potential impacts of 

their activities on the environment, including cultural resources. NEPA requires federal 

agencies to take into account cultural resources, including evaluation of potential impacts and 

mitigation measures, during the environmental analysis process. Regulations allow federal 

agencies to comply with Section 106 of NHPA through the use of the NEPA process and 

documentation, so long as the steps and standards of Section 800.8(c) of the Advisory Council 

on Historic Preservation’s (ACHP) regulations are met.

3.10.1 Cultural Context

The cultural history of northwestern Colorado is presented among several recent context 

studies. Reed and Metcalf’s (1999) study of the Northern Colorado River Basin provides 

applicable prehistoric and historic overviews as compiled by Frederic J. Athearn (1982) and 

Michael B. Husband (1984). Recorded archaeological sites within the region date throughout 

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the known time span of occupation by native peoples and document ways of life based on 

hunting and gathering along with some reliance on horticulture during more recent times. The 

oldest sites are over 11,000 radiocarbon years in age (BLM 2014). Site types include common 

lithic scatters and campsites. Lithic scatters are often denoted by a scattering of stone tools 

and stone debris from tool manufacture. Campsites often have such a scattering of stone 

artifacts but also have some evidence of habitation, such as fire hearths or, less commonly, tipi 

rings or pithouses. Among the less common kinds of sites are rock art sites, tool stone quarry 

sites, and burials.

Athearn (1982) presents a history of northwest Colorado in which he discusses various 

historical periods and themes, including: the fur trade, exploration, settlement, confrontation 

with native people, development of the livestock industry, mining, construction of railroads, 

etcetera. A document that discusses historical sites in Colorado in general and suggested 

research to better understand the historic era through archaeology is provided by Church et al. 

(2007). 

Furthermore, a regional overview of cultural resources administered by the BLM LSFO has 

been completed (McDonald and Metcalf 2006), in addition to valuable contextual data provided 

by synthesis reports of archaeological investigations conducted for a series of large pipeline 

projects in the BLM LSFO management area (Metcalf and Reed 2011; Rhode et al. 2010; Reed 

and Metcalf 2009).

3.10.2 Project Specific Inventory

As required by the NHPA, intensive archeological field investigations have been conducted on 

the Project Area (TRC Mariah 2006; WAS 2014). However, within the northern portion of the 

Project Area, six relatively small areas have not been surveyed. These areas all consist of 

steeply sloping terrain, and were not surveyed as the likelihood of encountering sites on such 

terrain is low. The previous inventories within the Project Area recorded a total of 46 sites 

(TRI Mariah 2006; WAS 2014). Of the 46 sites, none are NRHP-eligible but 3 need more data 

to determine their NRHP eligibility (SHPO 2013). The majority (43) of the sites were 

recommended as not eligible for inclusion on the NRHP and need no further management. 

Only NRHP-eligible and “needs data” sites are carried forward in the analysis (Section 4.10).

3.11 INDIAN CONCERNS

On May 21, 2015, the following Indian tribes were formally contacted for the Project: Eastern 

Shoshone Tribe, Ute Mountain Ute Tribe, Ute Indian Tribe, and the Southern Ute Tribe. On 

June 16, 2015, a Project description and request for consultation letter was sent to the 

Colorado State Historic Preservation Office (SHPO). Previous consultation for PR02 occurred 

in 2007 during the original NEPA analysis (OSMRE 2007). 

Within this area of Colorado, tribal consultations on a variety of project types have revealed 

several site types of concern. These include prehistoric and historic Indian rock art, eagle 

traps, vision quests, prehistoric cairns, and prehistoric trails. Consultation will be ongoing 

throughout the NEPA process.

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3.12 SOCIOECONOMICS

The Project Area is located approximately 30 miles (48 km) southwest of Craig and 22 miles 

(35 km) north of Meeker. These communities in Moffat and Rio Blanco counties, respectively,

are the most likely to be affected by mining in the Project Area. Table 3.12-1 shows the 

populations of these communities; ethnic distribution is discussed in Section 3.13.

Table 3.12-1 Population Estimates

Community 2000 Census 

Estimate

2010 Census 

Estimate 2013 Estimate

Craig 9,189 9,464 8,981

Meeker 2,242 2,475 2,493

Source: Census 2013

Per capita income for the two communities has risen between 28.3 and 53.2 percent between 

2000 and 2011 while throughout the State of Colorado it has risen 28.1 percent. The mean 

household income for the two communities has risen between 29.5 and 46.5 percent, 

compared to the state average of 30.1 percent between 2000 and 2010 (Census 2013). Table 

3.12-2 depicts the per capita income for the two communities and Table 3.12-3 shows the 

mean household income. From 2008 to 2014, Colowyo contributed an average of $29 million 

per year to the local economy through gross wages, insurance premiums paid for employees, 

and retirement fund contributions (Tri-State 2015a).

Table 3.12-2 Per Capita Personal Income

Community 2000 Estimate 2011 Estimate Percent Change

Craig $18,140 $23,274 28.3%

Meeker $17,647 $27,042 53.2%

State of Colorado $24,049 $30,816 28.1%

Source: Census 2013

Table 3.12-3 Mean Household Income

Community 2000 Estimate 2011 Estimate Percent Change

Craig $45,846 $59,384 29.5%

Meeker $40,496 $59,329 46.5%

State of Colorado $59,313 $77,149 30.1%

Source: Census 2013

In 2010, the largest employment industries for the two communities were educational and 

health care service, mining and oil and gas extraction (9.4 and 20 percent for Craig and Meeker, 

respectively), retail trade, arts, entertainment, recreation, accommodation, and food services. 

For comparison, in Colorado the largest employment industries are educational services, health 

care, and social assistance (19.6 percent). 

The unemployment rate for Moffat and Rio Blanco counties is 5.4 percent and 6.1 percent, 

respectively. The unemployment rate is slightly above the Colorado unemployment rate of 4.3 

percent (BLS 2015). 

Housing in the two communities is generally available. The housing market in the area has been 

on a steady growth cycle (Table 3.12-4).

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Table 3.12-4 Housing Characteristics 

Community

2000 

Median 

Home 

Price

2010 

Median 

Home 

Price

Percent 

Change

2000 

Median 

Rent

2010 

Median 

Rent

Percent 

Change

Craig $101,900 $160,100 57 $450 $739 64

Meeker $104,500 $186,900 78 $382 $685 79

State of 

Colorado $166,600 $236,600 42 $671 $833 24

Source: Census (2003), American FactFinder (2015), 

The top three private industry sectors by employment and income in Moffat County are mining, 

public administration, and retail trade (YVDP 2015). Colowyo Mine employs 220 people, of 

which, the large majority live in Moffat and Rio Blanco counties, mostly in the surrounding areas 

of Meeker and Craig. Tri-State pays over $25 million dollars in wages annually which get spent 

largely in Moffat and Rio Blanco counties (EDCC 2015). 

Many businesses that directly or indirectly support Colowyo Mine in Moffat and Rio Blanco 

counties exist because of the mining industry and include welding, fabrication, and equipment 

rental businesses. Even tertiary businesses depend heavily on Colowyo, most notably the hotel 

and restaurant businesses in Meeker and Craig. This equates to annual purchases in 

northwestern Colorado (Moffat, Rio Blanco, and Routt counties) of $19,768.00 and regional 

purchases (northwestern Colorado and southwestern Wyoming) of $39,934,000 (Tri-State 

2015a). 

Nearly 350,000 tons of coal was produced in Moffat County in September 2013, a 19 percent

decline in coal production from the previous September (YVDP 2015). The 12-month average 

for coal production in Moffat County was 340,000 tons, a decline from 2012 when the 12-

month average production was 410,000 tons. According to the 2014-2015 Community 

Indicators Report, year-to-date coal production through November 2013 was down almost 20

percent in Moffat County and 31 percent statewide. Nationally, coal production for the first 

half of 2013 was roughly 21 million tons, down about 4 percent from the same period in 2012

(YVDP 2015).

Another study conducted in 2015, the Measurement of Economic Activity for Coal Industry and 

Electrical Power Generation Industry in the Yampa-White River Region of Northwest 

Colorado (EDCC 2015), summarizes the impact of the coal mining industry in Moffat County, 

Rio Blanco County, Routt County, and the Yampa-White River Region. The coal mining 

industry in the region directly employs 4.6 percent of the total employees and accounts for 17.4

percent of the region's direct output (EDCC 2015). Specifically, Moffat County's coal mining 

sector contributes about $229 million to the direct gross regional product (GRP) which is 31 

percent of the $742 million GRP for the county. There are 776 direct employees in the 

industry, with total direct wages of about $61 million. The total impact of the coal mining 

industry in the county is 1,144 workers, $75 million in wages, and $283 million in output 

(EDCC 2015). Rio Blanco County's coal mining sector contributes slightly less than $55 million 

to the direct GRP or 14 percent of the $397 million for the county. There are 183 direct 

employees in the industry, with total direct wages greater than $14 million. The total impact of 

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the coal mining industry in Rio Blanco County is 241 workers, $16 million in wages, and $61 

million in output (EDCC 2015).

In 2014, Colowyo paid $1,402,538.11 in property taxes. Of that, $1,259,907.91 was paid to 

Moffat County, and $142,630.20 was paid to Rio Blanco County (Tri-State 2015a).

Federal coal lease royalty rates are 12.5 percent of the value of the coal removed from a 

surface mine (43 CFR 3473). Money collected through federal mineral leases and state 

severance taxes are distributed differently in Colorado. 51 percent of the federal mineral lease 

royalties are distributed to the federal government while 49 percent are returned to Colorado. 

Of the 49 percent returned to Colorado, 40 percent is used in the Local Impact Program 

managed by the Department of Local Affairs. That money is split between the local counties 

and a grant program that counties may apply for. From 2010 to 2014 the federal treasury

collected an average of $9.5 million per year in royalties from Colowyo for the Project Area

leases (Tri-State 2015a). Fifty percent of these royalties were returned to the State of 

Colorado for planning, construction, and maintenance of public facilities and services in the 

affected counties ($4.77 million per year).

Of the money collected through state severance taxes, 50 percent is distributed to the 

Department of Natural Resources’ State Trust fund and 50 percent is distributed to the 

Department of Local Affairs Local Impact fund. The Local Impact fund money is used in grant 

programs as well as distributed back to local jurisdictions where the mining takes place. In 

2014, Colowyo paid $1,285,287.39 in severance taxes (Tri-State 2015a).

3.13 ENVIRONMENTAL JUSTICE

Executive Order 12898 on Environmental Justice was issued on February 11, 1994. The 

purpose of the order is to identify and address, as appropriate, disproportionally high and 

adverse human health and environmental effects of programs, policies, or activities on minority

populations, low-income populations, and indigenous peoples. Relevant census data for Moffat 

and Rio Blanco Counties were collected to determine whether populations residing in the 

counties that are in the vicinity of the Project Area constituted “environmental justice 

populations.” According to the CEQ and EPA guidelines established to assist federal and state 

agencies, a minority population is present in a project area if:

• The minority population of the affected area exceeds 50 percent; or,

• The percentage of the minority population in the affected area is meaningfully greater 

than the percentage in the general population.

For Moffat County, 82.6 percent of the population is Caucasian, 14.1 percent is Hispanic or 

Latino, 1.4 percent is American Indian, 0.7 percent is Asian, and 0.5 percent is African 

American; the data for Rio Blanco County is nearly identical (Census 2015). This data indicates 

that there is not a minority population present in the Project Area that would be 

disproportionally affected by the Project.

The U.S. Census Bureau estimates poverty levels using a set of income thresholds that vary by 

family size and composition. If a household’s income is below income thresholds, the family and 

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all the individuals of that household are considered to be in poverty. Using this criterion, the 

Census Bureau provides estimates of the percentage of individuals that fall below the poverty 

level for each county in the United States. Within Moffat and Rio Blanco counties, the 2013 

poverty rate was 11.5 and 10.7 percent, respectively. These are below the 12.9 percent 

poverty level for the State of Colorado (Census 2014). This data indicates that there is not a 

low-income population that would be disproportionally affected by the Project.

Because there are no environmental justice populations present, environmental justice will not 

be discussed further.

3.14 VISUAL

The BLM utilizes Visual Resource Management (VRM), which is a system to help identify visual 

(scenic) values and minimize visual impacts to landscape character of public lands. The VRM 

system process involves inventorying scenic values, establishing management objectives for 

those values, and evaluating proposed activities to analyze effects and develop mitigations to 

meet established VRM objectives (BLM 1986). 

3.14.1 BLM Visual Resources Management

Visual Resource Inventory

A visual resource inventory (VRI) is a systematic process designed to determine the extent and

quality of visual resources in a given area. The inventory provides a means to determine visual 

values on public lands. The inventory process consists of scenic quality evaluation, viewer 

sensitivity level analysis, and delineation of distance zones. Scenic quality is a measure of the 

visual appeal of a parcel of land. Sensitivity measures the level of public concern for scenic 

quality. Distance zones describe the relative visibility of an area in terms of foreground, middle 

ground, and background based on the relative proximity of the landscape to a viewer at a fixed 

point. Based on a combination of these three categories, BLM lands fall into one of four VRI 

classes. Areas with high scenic quality and visual sensitivity in the foreground or middle ground 

are classified the highest. As scenic quality and/or sensitivity decline, and/or views are at a 

greater distance (in the background or seldom seen areas), areas are classified lower 

(BLM 1986). 

VRM Classes

VRM Classes are assigned to lands during the land use planning process by considering the VRI 

for an area in conjunction with the present and/or planned future use of an area. VRM class 

objectives define the level of change in the visual quality of the landscape that the management 

of an area would allow for. VRM class objectives are defined as follows:

• Class I Objective: To preserve the existing character of the landscape. The level of 

change to the characteristic landscape should be very low and must not attract 

attention.

• Class II Objective: To retain the existing character of the landscape. The level of 

change to the characteristic landscape should be low.

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• Class III Objective: To partially retain the existing character of the landscape. The 

level of change to the characteristic landscape should be moderate.

• Class IV Objective: To provide for management activities that require major 

modification of the existing character of the landscape. The level of change to the 

characteristic landscape can be high.

The BLM LSFO ROD and RMP (BLM 2011) states that areas suitable for coal mining are 

generally classified as VRM Class IV.

3.14.2 Project Area Visual Resources

VRM Classes

The BLM LSFO ROD and RMP (BLM 2011) classified the BLM-managed public lands in the 

southern portion of the Project Area as VRM Class IV. A parcel of approximately 80 acres of 

BLM-managed public lands in the northern portion of the Project Area is designated VRM Class 

III.

Description of Visual Resources of the Project Area

The Project Area is an area of rolling hills and low mesas incised by streams. In drainage 

bottoms, the view is enclosed and vegetated with low grasses and shrubs in varying shades of 

greens, golds, greys, and browns with softer textures. Mesa slopes and hillsides are steep and 

sparsely vegetated with coarse darker green shrubs and grasses surrounding light tan to red 

rock outcrops in the foreground and middle ground. In areas where the view is more open and 

panoramic, low mesas are soft and slightly rounded in shades of light green and tan to brown, 

creating gently undulating lines at the skyline. Low mesas in the distance at the horizon are 

darker shades of green and brown to black. Visible man-made features are road surfaces.

Sensitive Viewers

Potential sensitive viewers of the Project would be travelers on roadways in the vicinity of the 

Project. Public access in the vicinity of the Project Area is via State Highway 13 east of the 

Project Area, Moffat County Road 51 west of the Project Area, and Moffat County Roads 17 

and 32 north of the Project Area. Most of these access routes are located in drainage bottoms, 

which result in enclosed views and limited visibility of the surrounding landscape; but 

occasionally the landscape opens up to more panoramic views of the area. However, the 

Project Area is located on a mesa top at a higher elevation than viewers traveling on the 

roadways in the vicinity. Therefore, the Project Area is generally not visible from the 

roadways. 

Other sensitive viewers in the area would be recreationists who travel off-road. For the most 

part these would be hunters who would be in locations at higher elevations where the Project 

would be visible. Hunters would be traveling into areas with views of the Project Area at 

specific times of the year during hunting season. Recreational use of public lands in the vicinity 

of the Project Area other than hunting would be possible, but likely infrequent.

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3.15 RECREATION

The majority of the Project Area is private land. The dominant recreational activity in rural 

Moffat County, and the Project Area, is hunting. Camping and off-highway vehicle (OHV) uses

are commonly associated with hunting. Hunting is primarily archery and rifle hunting for deer, 

pronghorn, and elk and shotgun hunting for birds and small mammals. In recent years, land 

owners adjacent to the Project Area have been leasing their lands to hunters in increasing 

numbers. This trend may continue on lands adjacent to the Project Area, but the possibility for 

recreation on the Project Area, as long as mining activities are on-going, is highly unlikely due to 

public safety concerns. Touring, photography, bird watching, and other more passive 

recreational pursuits are also popular but do not occur in the Project Area due to safety 

concerns.

Recreation on BLM administered lands is managed in accordance with the LSFO RMP (BLM 

2011) which defines a variety of dispersed recreational activities in Moffat and Rio Blanco 

counties. In the LSFO RMP, two special recreation management areas (SRMAs) were identified 

within the BLM LSFO management area. Areas that are not designated as SRMAs are by default 

extensive recreation management areas (ERMAs), for which minimal capital investments are to 

be made. The Project Area and surrounding lands are designated as an ERMA where 

recreation use is dispersed and requires minimal management. OHV use is one of the fastest 

growing recreation activities on public lands (BLM 2011). In the LSRMP, OHV use on BLM land

in the Project Area is limited to existing roads and trails.

Within the Colowyo Mine boundary and the Project Area, no public hunting is allowed.

However, Colowyo allows its employees and their families to hunt on certain parcels of land owned by 

Colowyo within the permit boundary. Employees may not hunt where active mining is occurring. In 

general, publicly owned lands (i.e., BLM-administered federal lands and state school sections) 

are open to hunting if legal access is available. However, within the Project Area, all BLMadministered parcels are surrounded by state lands or Colowyo-owned land with limited to no 

access available. Due to safety concerns, however, public surface lands contained within an 

active mining area are closed to everyone, further limiting recreational use. 

3.16 PALEONTOLOGY

Paleontological resources comprise a fragile and nonrenewable scientific record of the history 

of life on earth. The Colorado State Paleontology Program Policy establishes guidelines for the 

management and protection of paleontological resources on public lands. Paleontological 

resources, such as fossil plant or animal remains, are discovered frequently in western U.S. coal 

mines where fresh, fossil-bearing rocks are exposed. Paleontological resources are integrally 

associated with the geologic rock units (e.g., formations) in which they are located. The 

Williams Fork Formation, where the Project Area is located, is rated by the State as having a 

high potential for discovery of fossils (Armstrong and Wolney 1989). Dinosaurs and other 

vertebrates, as well as fossil tracks and plants, have been found in the Williams Fork Formation.

The BLM has implemented a Potential Fossil Yield Classification (PFYC) system for classifying 

paleontological resources on public lands. Under the PFYC system, geologic units are classified 

from Class 1 to Class 5 based on the relative abundance of vertebrate fossils or uncommon 

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invertebrate or plant fossils, and their sensitivity to adverse impacts. A higher classification 

number indicates a higher fossil yield potential and greater sensitivity to adverse impacts. The 

Project Area is located in the Cretaceous Williams Fork formation. The Project Area is 

classified as PFYC Class 5 (BLM 2011). The potential for abundant vertebrate fossils or 

scientifically significant invertebrate or plant fossils in the Project Area is high.

3.17 ACCESS AND TRANSPORTATION

Access to the Colowyo Mine and Project Area is generally from Craig in Moffat County to the 

north and Meeker in Rio Blanco County to the south. Both communities lie along State 

Highway 13 which serves as the primary road leading north and south between Craig and 

Meeker. Approximately 11 miles (18 km) north of the mine entrance (near Hamilton), the 

average annual daily traffic (AADT) count for State Highway 13 in 2013 was 1,800 vehicles. Of 

this, 330 vehicles (18.3 percent) were truck traffic. Approximately 20 miles (32 km) south of 

the mine entrance (near Meeker), the AADT count in 2013 was 1,700 vehicles, of which 290 

vehicles (17.5 percent) were truck traffic (CDOT 2015). From State Highway 13, the Project 

Area is accessed by County Road 51. County Road 51 traverses through the Project Area in a 

northeast-southwest direction. County roads 17 and 32 access the north end of the Project 

Area from the north and northwest, respectively. State and county roads are usually 

constructed to higher standards than local or BLM roads and provide the primary arterial and 

collector road systems for access to and through private and BLM lands. While other roads 

lead into the mine from other directions along county roads, that access is through locked 

gates and generally does not account for a large amount of traffic. Mine use of public roadways 

occurs primarily when shifts change at the mine. Administrative staff generally works from 7:30 am to 

4 pm, maintenance staff work in two shifts from 7:00 am to 7:00 pm and 7:00 pm to 7:00 am, and 

production staff work in two shifts from 8:00 am to 8:00 pm and 8:00 pm to 8:00 am. 

Coal is currently transported from the mine (at the Gossard loadout) to coal markets by rail

(Figure 1-1) in unit trains, i.e. “a railway train that transports a single commodity directly 

from producer to consumer” (Merriam-Webster 2015). At current production rates, coal is 

shipped on approximately 250 unit trains per year. The mine is connected to a main rail line via 

a private rail spur that connects to the coal load out facility at the mine and runs north to two 

east-west rail lines 80 miles (129 km) southeast of Craig in Eagle County. The mine’s spur 

connects into the Moffat Tunnel line. Coal heading east of this intersection will pass through 

the Moffat Tunnel and deliver coal to the eastern slope of Colorado. Coal heading west of this 

intersection will join with a major east-west rail line that delivers coal throughout the country.

3.18 SOLID OR HAZARDOUS WASTE

No designated or illegal sites for solid or hazardous wastes have been identified within the 

Project Area. Field surveys that have been conducted have not identified any waste disposal 

practices that would cause deterioration of the environment.

As there is no coal preparation facility, no coal processing wastes are generated. Non-coal, 

nonhazardous solid waste, such as garbage, used tires, etc., is stored in a controlled manner 

around the operation in various waste receptacles and waste locations. Periodically the waste 

is disposed of in the backfill area of the pit and covered with a minimum 25 feet of overburden 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 3-67

Mining Plan Modification Environmental Assessment
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material. No waste is allowed on the bottom of the backfill area or below the anticipated 

groundwater level of backfilled areas. Nonhazardous used oil and grease, flammable liquids, etc. 

are stored in a tankfarm facility located near the shop facilities.

Colowyo’s status as a conditionally exempt small quantity generator of hazardous materials 

essentially indicates that Colowyo generates negligible amounts of hazardous waste. Hazardous 

wastes produced by current mining activities at the mine are handled in compliance with 

regulations promulgated under the Resource Conservation and Recovery Act, Federal Water 

Pollution Control Act (CWA), Safe Drinking Water Act, Toxic Substances Control Act, Mine 

Safety and Health Act, Department of Transportation, and the CAA. Mining operations must 

also comply with all state rules and regulations relating to hazardous material reporting, 

transportation, management, and disposal.

3.19 NOISE

Noise is an unwanted sound occurrence. A noise’s attributes (pitch, loudness, repetitiveness, 

vibration, variation, duration, and the inability to control the source) determine how it affects a 

receptor. To properly assess the noise resources for any area, consideration of the 

topography, climate, flora, and current ambient noise is required. The affected environment for 

noise impacts for wildlife is usually limited to a distance of 880 yards from the source based on 

current wildlife studies (Fletcher 1980). However, if residential housing has the potential to be 

impacted, the affected environment includes the distance from the source of the noise to the 

residence. 

The unit of sound level measurement (i.e. volume) is the decibel (dB), expressed as dBA 

(decibel-A weighted). The A-weighted decibel measure is used to evaluate ambient noise levels 

and common noise sources. Sound measurements in dBA give greater emphasis to sound at 

the mid- and high- frequency levels, which are more discernible to humans. The decibel is a 

logarithmic measurement; thus, the sound energy increases by a factor of 10 for every 10 dBA 

increase. 

Generally, natural noise levels will be around 35 dBA in rural areas away from communities and 

roads. Within a rural community, the man-made noise level ranges from 45 dBA to 52 dBA 

(Noise Effects Handbook 1998). The day-night sound level of residential areas should not 

exceed 55 dBA to protect against activity interference and annoyance (Noise Effects Handbook 

1998). Table 3.19-1 presents typical sound levels in dBA and subjective descriptions 

associated with various noise sources.

The Federal Noise Control Act of 1972 established a requirement that all federal agencies 

administer their programs to promote an environment free of noise that jeopardizes public 

health or welfare. Although the Occupational Safety and Health Administration (OSHA) have

the most extensive regulations in regard to noise pollution, these standards are only for noise 

levels within the workplace. 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 3-68

Mining Plan Modification Environmental Assessment
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Table 3.19-1 Sound Levels Associated With Ordinary Noise Sources

Noise Source Noise Level Subjective 

Description

Commercial Jet Take-Off 120 dBA Deafening

Road Construction Jackhammer 100 dBA Deafening

Busy Urban Street 90 dBA Very loud

Standard For Hearing Protection 8-Hour Exposure 

Permissible Exposure Limit (PEL) Action Level within Active 

Mining Facilities

90 dBA

85 dBA

Very loud

Loud - to very loud

Construction Equipment at 50 feet 80-75 dBA Loud

Freeway Traffic at 50 feet 70 dBA Loud

Noise Mitigation Level for Residential Areas Federal Housing 

Administration (FHA) 67 dBA Loud

Normal Conversation at 6 feet 60 dBA Moderate

Noise Mitigation Level for Undisturbed Lands (FHA) 57 dBA Moderate

Typical Office (interior) 50 dBA Moderate

Typical Residential (interior) 30 dBA Faint

EPA identifies outdoor noise limits to protect against effects on public health and welfare by an 

equivalent sound level (Leq), which is an A-weighted average measure over a given time. 

Outdoor limits of 55 dBA Leq have been identified as desirable to protect against speech 

interference and sleep disturbance for residential areas and areas with educational and 

healthcare facilities. Sites are generally acceptable to most people if they are exposed to 

outdoor noise levels of 65 dBA Leq or less, potentially unacceptable if they are exposed to 

levels of 65 – 75 dBA Leq, and unacceptable if exposed to levels of 75 dBA Leq or greater 

(Noise Effects Handbook 1998). Mine Safety and Health Act (MSHA) regulations require a 

mine operator to assure that no miner is exposed during any work shift to noise that exceeds 

the permissible instantaneous exposure level of 115 dBA, or an 8 hour time-weighted average 

sound level (TWA8) of 85 dBA (or equivalently a dose of 50 percent, integrating all sound levels 

from 80 dBA to at least 130 dBA) (30 CFR 62.130).

Ambient noise levels across the Project Area generally include natural sources such as wind, 

birds, and insects and noise associated with the active mining operation including blasting, coal 

loading/conveyance, crushing, and vehicle noise. Gun shots may be heard during hunting season 

or from target practice.

Noise generated from the active mining operations occurs from the operation of heavy trucks 

and machinery on a relatively constant basis (~90 dBA) including during nighttime hours. 

During blasting to open up coal resources, sound levels would raise to over 100 dBA. 

However, this only occurs on average of once per day and during the daytime. There have not 

been any complaints about noise related to either the mine or the rail line from the local community (D. 

Lempke, personal communication, July 8, 2015).

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 3-69

Mining Plan Modification Environmental Assessment
Chapter 3 – Affected Environment

3.20 LIVESTOCK GRAZING

Public rangelands administered by the BLM are used for livestock grazing and wildlife habitat. 

The Project Area overlaps five grazing allotments: Taylor Creek, East Fork Wilson Creek, 

Smith-Crawford, Colowyo Commons, and Lower Taylor Creek. Animal unit months (AUMs) 

are assigned to each grazing allotment; AUMs are defined as the amount of forage required to 

support one cow and her calf (if under six months) or five sheep and their lambs (if under six 

months) for one month. Within these five allotments there are 188 AUMs available for cattle 

forage and 45 AUMs available for sheep forage in the Project Area (Table 3.20-1). Grazing 

management must adhere to the BLM's Standards for Public Land Health and Guidelines for 

Livestock Grazing Management in Colorado (BLM 1995). Colowyo is the grazing leaseholder 

and subleases the grazing rights to a third party.

Table 3.20-1 Grazing Allotments

Allotment Total Acres Acres in Project 

Area

Total AUMs

Cattle/Sheep

AUMs in 

Project Area

Cattle/Sheep

Taylor Creek 8,419 5,490 170/43 111/28

East Fork Wilson 

Creek 1,019 382 170/43 63/16

Smith-Crawford 22,903 176 1,219/0 9/0

Colowyo Commons 35,572 173 347/173 2/1

Lower Taylor Creek 762 78 27/0 3/0

Totals 68,675 6,299 1,933/259 188/45

Source: BLM Geocommunicator database

Taylor Creek

There are 111 AUMs of forage available for cattle use generally from June 25 through October 

20 in the Project Area within the Taylor Creek Allotment; period of use varies according to 

pasture. There are 28 AUMs of forage available for sheep use from June 5 through July 5.

East Fork Wilson Creek

There are 63 AUMs of forage available for cattle use generally from June 25 through October 

20 in the Project Area within the East Fork Wilson Creek Allotment; period of use varies 

according to pasture. There are 16 AUMs of forage available for sheep use from June 5 

through July 5.

Smith-Crawford

There are 9 AUMs of forage available for cattle use generally from May 15 through November 

15 in the Project Area within the Smith-Crawford Allotment; period of use varies according to 

pasture. There is no sheep grazing on this allotment.

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 3-70

Mining Plan Modification Environmental Assessment
Chapter 3 – Affected Environment

Colowyo Commons

There are 2 AUMs of forage available for cattle use from May 1 through October 31 in the 

Project Area within the Colowyo Commons Allotment. There is 1 AUM of forage available for 

sheep use from June 1 through October 31.

Lower Taylor Creek

There are 3 AUMs of forage available for cattle use from May 1 through October 14 in the 

Project Area within the Lower Taylor Creek Allotment. There is no sheep grazing on this 

allotment.

3.21 SOILS

Soils within the Project Area are variable, depending on the combination of parent materials, 

slope, microclimate, aspect, location and stability of the slopes, age, and their history of use. 

The dominant soil types were formed primarily from alluvium, colluvium, or in-place residuum 

of sandy, silty, or clayey bedrock. Alluvial soils are located in drainages derived from the 

transport of upslope materials by water processes. Colluvial soils are derived from materials 

transported from upslope positions by gravity. Relatively unweathered bedrock exposures are 

also observed, where soil development processes do not keep up with the tendency of the 

rock to erode from water or wind processes.

The soils of the Project Area are typical of soils found in the cold, semi-arid region of 

northwest Colorado. The soils range from shallow (less than 20 inches to bedrock) and 

moderately deep (20-40 inches) to deep (greater than 40 inches thick), and are developing in 

weathered, interbedded sandstone, siltstone, and shale, as well as in local colluvium, slopewash, 

and stream-laid alluvium. Plant rooting depth corresponds with soil depth. Most soils are 

moderately well drained to well drained. Soils support mostly native vegetation used for 

livestock grazing and wildlife habitat. 

The soil survey for Moffat County was completed by the USDA Natural Resources 

Conservation Service (NRCS) and was used to describe the various mapping units below 

(NRCS 2005). The older NRCS Rio Blanco County soil survey information (NRCS 1982) was 

used for the southern part of the Project Area; both sets of information were compiled by 

Colowyo (2007) (Figure 3-11). The two surveys used different mapping unit names due to 

the time of the survey and changes in NRCS classification system. Similar, essentially equivalent 

soil types were given different mapping unit numbers and names depending upon which survey 

applied.

Close to 30 soil mapping units were determined to occur within the bulk of the Project Area in 

Moffat County and close to 10 others were determined to occur within the portion of the 

Project Area that occurs in Rio Blanco County (Figure 3-11). However, based on the 

inference above, it is likely that there is some overlap in these numbers. The dominant soil 

types found in the Project Area are briefly described below, by county. 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 3-71

Mining Plan Modification Environmental Assessment
Colorado

UV13

SCS

SCS

SCS

SCS

UV13

UV51

UV32

UV17

UV180

Moffat

Rio Blanco

Future Planned

Disturbance

160

160

197

38

38

113

66

117

26

108

142

52 108

160

108

108

149

37

108

26

26

160

206

108

77

77

38

135

117

52

135

25

26 135

149

142

10

197

113

113

197

37

206

206

206

206

206

206

206

206

206

206

197

197

197

197

197

37

37

25

25

25

197

197

197

217

25

217

135

135

135

117

3

216

38

142

142

142

142

141

163

38

134

25

26

197

142

38

197

25

216

57

57

57

57

57

77

98

98 91

91

57

98 84

77 77

98 98

57

91

57

91

91 98

Soils

3-11

Colowyo Coal Mine, South Taylor/Lower Wilson

Permit Expansion Area Mining Plan Modification

Environmental Assessment

($$ ̄

0 4,000 8,000

Feet

1:48,000 (At Original document size of 11x17)

Project Area

Future Planned Disturbance

Actual Disturbance since PR 02

Sediment Control Structure (SCS)

County Road

Highway

County Boundary

Project 

Location

Notes

1: Coordinate System: NAD 1983 UTM Zone 13N

2: Service Layer Credits: Copyright:© 2013 National

Geographic Society, i-cubed

Disclaimer: Figure prepared for OSMRE by Stantec. Stantec assumes no

responsibility for data supplied in electronic format. The recipient

accepts full responsibility for verifying the accuracy and completeness

of the data. The recipient releases Stantec, its officers, employees,

consultants and agents, from any and all claims arising in any way from

the content or provision of the data.

Figure No.

Title

3 : Adderton loam, 1 to 10 percent slopes

10 : Battlement fine sandy loam, 0 to 3

percent slopes

25 : Campspass fine sandy loam, 3 to 12

percent slopes

26 : Campspass fine sandy loam, 12 to 25

percent slopes

37 : Cochetopa loam, 12 to 25 percent

slopes

38 : Cochetopa loam, 25 to 65 percent

slopes

39 : Cochetopa loam, warm, 3 to 12

percent slopes

52 : Danavore-Waybe complex, 5 to 30

percent slopes

57 : Owen Creek-Jerry-Burnette loams, 5

to 35 percent slopes

66 : Evanot loam, 1 to 12 percent slopes

77 : Forelle loam, 3 to 12 percent slopes

77 : Rhone-Northwater-Lamphier loams, 3

to 50 percent slopes

84 : Silas variant loam

91 : Torriorthents-Rock outcrop complex,

15 to 90 percent slopes

98 : Waybe-Vandamore variant-Rock

outcrop complex, 5 to 30 percent slopes

108 : Jerry-Cochetopa complex, 5 to 35

percent slopes

113 : Kemmerer-Yamo complex, 5 to 30

percent slopes

117 : Lamphier-Jerry complex, 25 to 65

percent slopes

134 : Morapos loam, 3 to 12 percent

slopes

135 : Morapos loam, 12 to 25 percent

slopes

141 : Nortez, cool-Morapos complex, 3 to

12 percent slopes

142 : Nortez, cool-Morapos complex, 12

to 25 percent slopes

149 : Pinelli loam, 3 to 12 percent slopes

160 : Rock outcrop-Torriorthents complex,

50 to 75 percent slopes

163 : Rock River sandy loam, 12 to 25

percent slopes

197 : Torriorthents-Rock outcrop,

sandstone complex, 25 to 75 percent

slopes

206 : Ustorthents, frigid-Borolls complex, 25

to 75 percent slopes

216 : Yamo loam, 3 to 15 percent slopes

217 : Yamo loam, 15 to 30 percent slopes

Rio Blanco & Moffat Counties

Colorado

Project Location

Project
Chapter 3 – Affected Environment

Moffat County Soil Mapping Units (NRCS 2005)

Map Unit 3 - Adderton loam, 1 to 10 percent slopes

The elevation for this mapping unit is 7,000 to 8,500 feet amsl. Annual precipitation is 16 to 20

inches and the frost free period is 50 to 75 days. Primary makeup of this mapping unit is 

Adderton and similar soils, with some minor components that are moderately well drained or 

somewhat poorly drained. The unit is found on alluvial fans and in drainage ways, and soils 

formed in alluvium derived from various sedimentary rock types. This soil type is well drained. 

Map Unit 10 - Battlement fine sandy loam, 0 to 3 percent slopes 

The elevation for this mapping unit is 6,000 to 6,800 feet amsl. Annual precipitation is 11 to 15

inches and the frost free period is 75 to 90 days. Battlement fine sandy loam is the dominant 

soil in this unit, but also included are small areas of Cowestgien soils and Battlement saline soils. 

The parent material is alluvium. This soil type is well drained and moderately well drained. It is 

found on floodplains and stream terraces.

Map Unit 25 - Campspass fine sandy loam, 3 to 12 percent slopes

The elevation for this mapping unit is 6,800 to 7,600 feet amsl. Annual precipitation is 16 to 18 

inches and the frost free period is 65 to 85 days. Campspass and similar soils make up 90 

percent in the mapping unit with minor components making up the remaining 10 percent. The 

parent material is residuum, derived from sandstone and shale. This soil type is well drained. 

The minor soils are rock outcrops and Morapos and similar soils. 

Map Unit 26 - Campspass fine sandy loam, 12 to 25 percent slopes

The elevation for this mapping unit is 6,800 to 7,600 feet amsl. Annual precipitation is 16 to 18 

inches and the average frost-free period is 65 to 85 days. Campspass fine sandy loam is the 

dominant soil in this unit, but small areas of Nortez soils and rock outcrop are also included. 

The parent material is residuum derived from sandstone and shale. This soil type is very deep 

and well drained. It is found on mountainsides.

Map Unit 37 - Cochetopa loam, 12 to 25 percent slopes

The elevation for this mapping unit is 7,200 to 8,300 feet amsl. Annual precipitation is 18 to 20 

inches and the frost-free period is 50 to 75 days. Eighty-five percent of the mapping unit is 

Cochetopa soil with 15 percent minor component. The fine, montmorillonitic Argic Pachic 

Cryoborolls has residuum derived from sandstone and shale parent material and is a deep, welldrained soil. The minor soils are Jerry and similar soils, and Routt and similar soils.

Map Unit 38 - Cochetopa loam, 25 to 65 percent slopes

The elevation for this mapping unit is 7,200 to 8,500 feet amsl. Annual precipitation is 18 to 20 

inches and the average frost-free period is 50 to 75 days. Cochetopa loam is the dominant soil 

type in this unit, but also included are a few small areas of rock outcrop, soils that are shallow 

over sandstone, and Jerry soils. The parent material is residuum derived from sandstone and 

shale. This soil is very deep, and well drained. It is found on mountainsides. 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 3-73

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Map Unit 39 - Cochetopa loam, 3 to 12 percent slopes

The elevation for this mapping unit is 7,200 to 8,300 feet amsl. Annual precipitation is 18 to 20 

inches and the average frost-free period is 50 to 75 days. Cochetopa loam is the dominant soil 

type in this unit, but also included are a few small areas of Jerry soils and Routt soils. The 

parent material is residuum derived from sandstone and shale. This soil is very deep, and well

drained. It is found on hilltops and plateaus.

Map Unit 52 - Danavore-Waybe complex, 5 to 30 percent slopes

The elevation for this mapping unit is 7,200 to 8,600 feet amsl. Annual precipitation is 18 to 20 

inches and the average frost-free period is 50 to 75 days. This unit is 45 percent Danavore soil 

and 30 percent Waybe soil. Included in this unit are small areas of rock outcrop, and soils 

similar to the Danavore soil but have dark colored surface layers. Danavore soils formed in 

residuum derived from interbedded sandstone and shale, and Waybe formed in residuum 

derived from shale. Both the Danavore and Waybe soils are well drained. This unit is found on 

narrow ridge crests and mountain sides. 

Map Unit 66 - Evanot loam, 1 to 12 percent slopes

The elevation for this mapping unit is 6,200 to 7,200 feet amsl. The average annual 

precipitation is 13 to 15 inches and the average frost-free period is 75 to 95 days. The 

dominant soil type is Evanot loam, but included in this unit are small areas of Forelle soils. This 

mapping unit formed in loess, is a very deep, well-drained soil, and is found on benches and 

hillslopes. 

Map Unit 77 - Forelle loam, 3 to 12 percent slopes

The elevation for this mapping unit is 6,200 to 7,200 feet amsl. The average annual 

precipitation is 11 to 13 inches and the average frost-free period is 75 to 95 days. This unit is 

85 percent Forelle and similar soil. It is formed in loess and in alluvium derived from shale and 

sandstone. The Forelle soil is well drained. This unit is found on benches.

Map Unit 108 - Jerry-Cochetopa Loams, 5 to 35 percent slopes

The elevation for this mapping unit is 7,200 to 8,600 feet amsl. Annual precipitation is 18 to 20

inches and the frost free period is 50 to 75 days. This unit is 50 percent Jerry soil and 35 

percent Cochetopa soil, with minor components of several other soils. The parent material of 

both major soils is residuum, derived from shale. Both are well drained. The minor soils 

include Waybe soils, Danavore soils, Lamphier soils, and Skyway soils, as well a soil similar to 

the Jerry soil but which is moderately deep to shale bedrock.

Map Unit 113 - Kemmerer-Yamo complex, 5 to 30 percent slopes

The elevation for this mapping unit is 6,100 to 7,200 feet amsl. The average annual 

precipitation is 11 to 13 inches and the average frost-free period is 75 to 95 days. This unit is 

60 percent Kemmerer soil and 20 percent Yamo soil. Included in this unit are small areas of 

Moyerson, Pinelli and Forelle soils. The Kemmerer soil is moderately deep and well drained. It 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 3-74

Mining Plan Modification Environmental Assessment
Chapter 3 – Affected Environment

formed in residuum derived from shale. The Yamo series is very deep and well drained. It is 

formed in alluvium derived from sandstone and in loess. This mapping unit is found on hillsides.

Map Unit 117 - Lamphier-Jerry complex, 25 to 65 percent slopes

The elevation for this mapping unit is 7,200 to 8,600 feet amsl. The average annual 

precipitation is 18 to 20 inches and the average frost-free period is 50 to 75 days. This unit is 

45 percent Lamphier soil and 30 percent Jerry soil. Included in this unit are small areas of rock 

outcrop, and Danavore soils, Skyway soils, and soils that are moderately deep and contain more 

than 35 percent rock fragments. The Lamphier soil is very deep and well drained. It formed in 

mixed colluvium and residuum derived from sandstone. The Jerry soil is very deep and well 

drained. It formed in colluvium and residuum derived from shale. This map unit is on mountain 

sides. 

Map Unit 134 - Morapos loam, 3 to 12 percent slopes

The elevation for this mapping unit is 6,400 to 7,600 feet amsl. The average annual 

precipitation is 16 to 18 inches and the average frost-free period is 65 to 85 days. The 

dominant soil in the unit is Morapos, which is a very deep, well-drained soil. It formed in 

residuum derived from shale and in loess. Included in this unit are small areas of Nortez soils 

and Campspass soils. This mapping unit is found on plateaus. 

Map Unit 135 - Morapos loam, 12 to 25 percent slopes

The elevation for this mapping unit is 6,400 to 7,600 feet amsl. The average annual 

precipitation is 16 to 18 inches and the average frost-free period is 65 to 85 days. This unit is 

85 percent Morapos and similar soils. It is formed in residuum derived from shale. The

Morapos soil is well drained. It is found on mountain slopes.

Map Unit 141 - Nortez, Cool-Morapos loams, 3 to 12 percent slopes

The elevation for this mapping unit is 6,400 to 7,600 feet amsl. The average annual 

precipitation is 16 to 18 inches and the average frost-free period is 65 to 85 days. This unit is 

50 percent Nortez soil and 40 percent Morapos soil. Included in this unit are small areas of 

rock outcrop, Maudlin soils, Duffymont soils, and Iles soils. The Nortez soils are moderately 

deep and well drained. It formed in residuum derived from interbedded sandstone and shale. 

The Morapos soil is very deep and well drained. It formed in residuum derived from shale. 

This map unit is located on plateaus.

Map Unit 142 - Nortez, Cool-Morapos complex, 12 to 25 percent slopes

The elevation for this mapping unit is 6,400 to 7,600 feet amsl. Annual precipitation is 16 to 18 

inches and the frost free period is 65 to 85 days. Nortez and similar soils account for 50 

percent of this soil type while Morapos and similar soils account for 40 percent, and minor 

components accounting for 10 percent. Nortez soils are derived from interbedded sandstone 

and shale while Morapos soils are derived from shale. This soil type is well drained. The minor 

components of this unit include rock outcrop, Mauslin and similar soils, Duffymont and similar 

soils, and Cochetopa and similar soils.

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 3-75

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Map Unit 149 - Pinelli loam, 3 to 12 percent slopes

The elevation for this mapping unit is 6,200 to 7,000 feet. The average annual precipitation is 

12 to 14 inches and the average frost-free period is 75 to 95 days. The dominant soil is Pinelli 

loam, and there are a few small areas of Evanot and Forelle soils. The Pinelli series consists of 

very deep, well-drained soils that are found on the benches and alluvial fans. Pinelli soils are 

formed in alluvium derived from shale and in loess.

Map Unit 160 - Rock outcrop-Torriorthents complex, 50 to 75 percent slopes

The elevation for this mapping unit is 5,900 to 8,000 feet amsl. Annual precipitation is 9 to 16

inches and the frost-free period is 75 to 105 days. Seventy percent of the map unit is rock 

outcrop, 25 percent are Torriorthents and similar soils, and 5 percent minor components. 

Rock outcrop is not described as a soil, thus depth and drainage classes are not applicable. 

Torriorthent soils are shallow and well-drained.

Map Unit 163 - Rock River sandy loam, 12 to 25 percent slopes

The elevation for this mapping unit is 6,200 to 7,300 feet amsl. The average annual 

precipitation is 11 to 13 inches and the average frost-free period is 75 to 95 days. The 

dominant soil in this mapping unit is Rock River sandy loam. Included in this unit are small 

areas of Forelle soils and Beriake soils. The Rock River sandy loam is well drained soil that 

formed in residuum derived from sandstone. This mapping unit is found on hill sides. 

Map Unit 197 - Torriorthents-Rock outcrop, Sandstone complex, 25 to 75 percent slopes 

The elevation for this mapping unit is 6,000 to 8,000 feet amsl. Annual precipitation is 9 to17 

inches and the frost-free period is 75 to 105 days. Fifty-five percent of the map unit is 

Torriorthents and similar soils, 35 percent are rock outcrop, and 10 percent minor 

components. Torriorthent soils are shallow and well-drained. The minor soil is Deep Loamy 

Soils and similar soils.

Map Unit 206 - Ustorthents, Frigid-Borolls complex, 25 to 75 percent slopes

The elevation for this mapping unit is 7,000 to 8,500 feet amsl. Annual precipitation is 16 to 20 

inches and the freeze free period is 50 to 85 days. Ustorthents and similar soils account for 55 

percent of this unit while Borolls and similar soils account for 35 percent with the remaining 10 

percent minor components. Both Ustorthents and Borolls soils are derived from sedimentary 

rocks and are well-drained. Minor components include Abor and similar soils, and Rencot and 

similar soils.

Map Unit 216 - Yamo loam, 3 to 15 percent slopes

The elevation for this mapping unit is 6,200 to 7,000 feet amsl. The average annual 

precipitation is 11 to 13 inches and the average frost-free period is 75 to 95 days. Yamo soils 

are the dominant soil type in this mapping unit. Yamo soils are formed in alluvium derived from 

sandstone and in loess. They are well drained soils. Included in this unit are a few small areas 

of Forelle soils. This mapping unit is found on the toeslopes of hills and benches. 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 3-76

Mining Plan Modification Environmental Assessment
Chapter 3 – Affected Environment

Map Unit 217 - Yamo loam, 15 to 30 percent slopes

The elevation for this mapping unit is 6,200 to 7,000 feet amsl. The average annual 

precipitation is 11 to 13 inches and the average frost-free period is 75 to 95 days. Included in 

this unit are small areas of soil similar to the Yamo loam that has sandstone bedrock at a depth 

of 20 to 40 inches. Also included are small areas of rock outcrop. The Yamo loam is a very

deep, well-drained soil found on hill sides. It formed in loess and residuum derived from 

sandstone. 

Rio Blanco County Soil Mapping Units (NRCS 1982)

Map Unit 57 - Owen Creek-Jerry-Burnette Loams, 5 to 35 percent slopes

The elevation for this mapping unit is 7,200 to 8,600 feet amsl. Annual precipitation is 18 to 22 

inches and the freeze free period is 45 to 75 days. Owen Creek and similar soils account for 

40 percent of this unit, Jerry and similar soils account for 30 percent, and Burnette and similar 

soils account for 20 percent. The remaining 10 percent are minor components. Parent 

material of the three dominant soils is residuum weathered from sandstone and shale. They 

are well drained and moderately deep (Owen Creek) to deep (Jerry and Burnette). This unit 

appears to correlate with Moffat County Map Unit 108.

Map Unit 77 - Rhone-Northwater-Lamphier loams, 3 to 50 percent slopes

Note that both the Moffat and Rio Blanco surveys have a mapping unit 77 in the Project Area; 

they are different units. The elevation for this mapping unit is 7,400 to 8,600 feet amsl. The 

average annual precipitation is 18 to 22 inches and the average frost-free period is 45 to 75 

days. This unit is 40 percent Rhone loam that has slopes of 3 to 50 percent, 30 percent 

Northwater loam that has slopes of 3 to 50 percent, and 20 percent Lamphier loam that has 

slopes of 8 to 35 percent. Included in this unit are small areas of Burnette, Cochetopa, Jerry, 

and Silas loams. The Rhone and Northwater soils are deep and well drained. They formed in 

residuum derived dominantly from sandstone. The Lamphier soil is very deep and well drained. 

It formed in mixed colluvium and residuum derived from sandstone. This map unit is on 

mountain sides and valley sides. 

Map Unit 84 - Silas Variant loam, 1 to 3 percent slopes

Elevation for this unit is 7,000 to 7,500 feet amsl. The average annual precipitation is 16 to 20 

inches and the average frost-free period is 80 to 105 days. The Silas variant loam is the 

dominant soil, but included in this unit are small areas of Hagga and Shawa loams. The Silas 

variant loam is a deep, well-drained soil on alluvial valley floors, on fans, and in swales on 

terraces. It formed in mixed alluvium. 

Map Unit 91 - Torriorthents-Rock outcrop, 15 to 90 percent slopes 

The elevation for this mapping unit is 5,100 to 7,500 feet amsl. Annual precipitation is 8 to18 

inches and the frost-free period is 70 to 130 days. Fifty percent of the map unit is 

Torriorthents and similar soils, 30 percent are rock outcrop, and 15 percent minor 

components. Torriorthent soils are shallow and well-drained. Rock outcrop is not described 

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Chapter 3 – Affected Environment

as a soil, thus depth and drainage classes are not applicable. This unit appears to correlate with 

Moffat County Map Unit 197.

Map Unit 98 - Waybe-Vandamore variant-Rock outcrop complex, 5 to 30 percent slopes

The elevation for this mapping unit is 7,400 to 8,600 feet amsl. Annual precipitation is 16 to 20

inches and the freeze free period is 45 to 75 days. Waybe and similar soils account for 45

percent of this unit, Vandamore variant and similar soils account for 25 percent, and rock 

outcrop accounts for 20 percent. The remaining 10 percent are minor components. Parent 

material of the two dominant soils is interbedded clayey residuum weathered from sandstone 

and shale. They are well drained and shallow (Waybe) to moderately deep (Vandamore 

variant). Rock outcrop is not described as a soil, thus parent material, depth, and drainage 

classes are not applicable.

3.22 PRIME FARMLANDS

CDRMS has determined that no prime farmlands exist within the Project Area (CDRMS 2007). 

This determination was based on: 1) a December 18, 1980 letter from the NRCS which 

documented that no prime farmland mapping units are located within the pre-PR02 permit 

area; 2) Colowyo consultation with NRCS in 2002 in which NRCS indicated that no areas of 

prime farmland are present in the PR02 area; and 3) Colowyo’s assessments of soil survey 

information (Colowyo 2007). Therefore prime farmlands will not be discussed further. Prime 

farmland information can be found in the mine permitting information (Colowyo 2007) in 

Section 2.04.12.

3.23 ALLUVIAL VALLEY FLOORS

Pursuant to the SMCRA and in accordance with federal regulations at 30 CFR 785.19 a. (2) i., 

an alluvial valley floor (AVF) is defined as a valley: 1) that is located in the arid or semi-arid 

regions of the U.S. (west of the 100th meridian west longitude); 2) that contains deposits laid 

down by one or more streams; 3) where at least one stream currently exists; and 4) where 

there is sufficient water available to support agriculture. Pursuant to the SMCRA and the 

CDRMS, “alluvial valley floors” means “the unconsolidated stream-laid deposits holding streams 

with water availability sufficient for subirrigation or flood irrigation agricultural activities but 

does not include upland areas which are generally overlain by a veneer of colluvial deposits 

composed chiefly of debris from sheet erosion, deposits formed by unconcentrated runoff or 

slope wash, together with talus, other mass movement accumulations and windblown deposits.”

The SMCRA further defines “unconsolidated stream-laid deposits holding streams” as meaning 

“all flood plains and terraces located in the lower reaches of valleys which contain perennial or 

other streams with channels that are greater than three feet in bankfull width and greater than 

0.5 feet in bankfull depth”. Because AVFs are critical for agriculture in arid and semi-arid 

regions, the SMCRA requires the regulatory authority (CDRMS in Colorado) to determine if 

AVFs exist within or adjacent to a proposed surface coal mining area. If CDRMS determines 

one or more alluvial valley floors do exist, the SMCRA requires that CDRMS then determine 

whether the proposed mining operations may affect the alluvial valley floor, or the waters that 

supply it. If the AVFs or associated water sources may be affected, CDRMS may then either 

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prohibit mining or require the mining permit applicant to comply with specific performance 

criteria to eliminate or mitigate the potential effects on the AVFs or their water sources. 

As a part of CDRMS’ Proposed Decision and Findings of Compliance for the Colowyo Coal 

Mine C-1981-019 Permit Revision No. 2 dated May 4, 2007, CDRMS determined that AVFs

exist within or adjacent to the Project Area, associated with Wilson Creek and Good Spring 

Creek (CDRMS 2007). It also determined that neither Taylor Creek nor West Fork Good 

Spring Creek met the criteria to be called an AVF. The AVF characteristics of Wilson and 

Good Spring creeks are described below. These areas are outside the areas to be mined.

Wilson Creek was found to contain sufficient Quaternary aged, unconsolidated, stream-laid 

materials, as well as sufficient water to support sub-irrigation. Further, portions of Wilson 

Creek within and downstream of the Project Area have likely been historically irrigated using 

flood irrigation practices. As of 2007, grass was being flood irrigated along a stream reach 

upstream of the Project Area. CDRMS (2007) thus determined that AVFs are present from the 

confluence of East and West Forks of Wilson Creek downstream to “the approximate center 

of Section 7, T3N, R93W”, as well as from the southeast quarter of Section 21, T4N, R93W 

downstream to the mouth of Wilson Creek. The reach in between these two segments of 

Wilson Creek is largely affected by an erosion and mass wasting event and was thus excluded 

from the determination.

Good Spring Creek was also found to contain sufficient Quaternary aged, unconsolidated, 

stream-laid materials, as well as sufficient water for sub-irrigation. Portions of Good Spring 

Creek valley, as of 2007, were also flood irrigated for pasture grass for hay and livestock forage 

production. CDRMS (2007) thus determined that an AVF is present from the confluence with 

West Fork Good Spring Creek downstream to its mouth.

The identified AVFs associated with Wilson and Good Spring creeks are mostly outside of (but 

close to) the Project Area (Figures 3-5a and 3-5b), though short reaches are within its 

boundaries. However, they do not occur within areas to be mined.

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 3-79

Mining Plan Modification Environmental Assessment
Chapter 4 – Environmental Consequences

CHAPTER 4 ENVIRONMENTAL CONSEQUENCES (DIRECT 

AND INDIRECT IMPACTS) 

4.1 INTRODUCTION

This chapter discusses the potential physical, biological, cultural, and socioeconomic direct and 

indirect effects1,2 of Alternative A (Proposed Action, PR02 as Approved in 2007), Alternative B

(PR02 as Revised), and the No Action Alternative as described in Chapter 2. Direct impacts 

are defined as those impacts which are caused by the action and occur at the same time and 

place. Indirect impacts are those that are caused by the action and occur later in time or are 

farther removed in distance, but are still reasonably foreseeable. Impacts may also be short 

term (also referred to as temporary) or long term. Short-term impacts generally occur for a 

short period during a specific point in the mining process. Long-term impacts would generally 

last the life of the Project and beyond. Finally, impacts are described by their level of 

significance (i.e., major, moderate, minor, negligible, or no impact). An impact is considered to 

be major if it would result in a substantial change to the environment. An impact is considered 

moderate or minor if it would not result in a substantial environmental change but could still 

have some effect. The determination of whether an impact is moderate or minor varies for 

each resource and the context of the specific proposed action. In contrast to no impact, a 

negligible impact is one that would occur but at the lowest limits of detection of an effect. The 

analysis applies quantitative thresholds when available, to determine the level of significance. 

Other issues have been analyzed qualitatively where necessary. 

NEPA requires federal agencies to take a hard look at and disclose to the public the potential 

effects on the human environment of proposed future projects or activities that require a 

federal approval. As such, in the case of a typical project proposed for the future, OSMRE 

would determine and analyze the nature and scope of future impacts that would potentially 

occur if the project or action were to either be approved, or not approved by OSMRE. In a 

typical case, the EA would inform the federal agency of the nature and scope of potential 

environmental impacts of the proposed project before a decision on the project is made. 

However, in the case of this EA, as required by the May 8, 2015 court order (WildEarth 

Guardians v. U.S. Office of Surface Mining et al., Case 1:13-cv-00518-RBJ [D. Colo. 2015]), 

OSMRE must re-evaluate the mining plan modification for PR02 that was approved by the 

ASLM in 2007 and has been implemented through mining coal from the South Taylor Pit over 

the past seven years. In this context, each resource section in Chapter 4 below is organized in 

the following manner:

• Alternative A – For this alternative, the analysis goes back in time and evaluates the 

Project as if no mining or related surface disturbance for PR02 has yet occurred. This is 

a very unusual approach to be utilized in a NEPA document but is necessary to 

1 Environmental Justice and Prime Farmlands are not discussed in Chapter 4 because these resources do not occur 

in the Project Area.

2 Cumulative impacts are discussed in Chapter 5.

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 4-1 

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Chapter 4 – Environmental Consequences

effectively address the court order. This alternative includes a description and 

discussion of the potential impacts of PR02 as it was approved in 2007 from the 

perspective of analyzing the “future” (2007 and later) effects of the Project. The effects 

are analyzed as if mining would occur in accordance with PR02 as approved in 2007 

(Chapter 2, Colowyo 2007) without any subsequent revisions. In other words, if 

mining proceeded exactly how it was authorized under PR02 as approved in 2007, 

Alternative A would have included 1,1813 acres of planned new surface disturbance. In 

addition, under PR02 as approved in 2007, mining was planned to end and the South 

Taylor final pit closure was planned to commence in 2017. The final active reclamation 

(i.e., regrading, not vegetation growth) would occur over three years until 

approximately 2020. The analysis of the potential impacts for Alternative A was 

performed for this EA with the information that would have been available to OSMRE 

back in 2007. 

• Alternative B – Impacts described and discussed under Alternative B include both 

impacts that have already occurred, as well future potential impacts, which is not typical 

for NEPA documents. The impact discussion for this alternative first includes a 

description of the impacts that have already occurred since mining began in 2008 under 

the approved PR02 with subsequent revisions, up through the present (previous 

impacts). Approximately 789 acres of new surface disturbance has already occurred 

since 2007, which comprises nearly the entire new surface disturbance associated with 

Alternative B. In addition, approximately 66 acres of reclamation has already occurred 

under Alternative B4

. The discussion of previous impacts is followed by a description 

and discussion of the impacts that could be expected to occur between the remainder 

of 2015 and the end of projected mining under the revised PR02 in about 2019 

(potential impacts). Only approximately 20 acres of additional new surface disturbance

(for a total of 809 acres) is planned under Alternative B. This new 20-acre disturbance 

would occur during reclamation activities and after mining is complete. The final active 

reclamation would occur until approximately 2022. 

• No Action Alternative – The “previous impacts” are described under Alternative B but 

apply to the time period from 2008 to 2015. These descriptions are not repeated 

under the No Action Alternative. Instead, the impact description and discussion focuses 

on future potential impacts resulting from implementation of No Action. Under this 

alternative, the ASLM would not re-approve the mining plan modification for PR02 as a 

result of this re-evaluation. This would mean that the mining operations at the South 

Taylor pit would cease in approximately September 2015, and South Taylor final pit 

closure activities would commence. Reclamation of all remaining disturbed areas would 

also commence with closure activities; similar to the action alternatives, active 

reclamation would occur over the next three years. Colowyo would be responsible 

under their lease terms and their SMCRA permit to complete all reclamation 

requirements for PR02. 

3

 Rounded from 1,180.7 (Chapter 2) 4 To date, this reclamation has included backfilling, grading, and topsoiling of 66 acres, and seeding of 54 acres.

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 4-2 

Mining Plan Modification Environmental Assessment

 
Chapter 4 – Environmental Consequences

4.1.1 Summary Comparison of Direct and Indirect Environmental Impacts

Table 4.1-1 summarizes and compares the potential environmental direct and indirect impacts 

associated with the alternatives (cumulative impacts are discussed in Chapter 5). 

Table 4.1-1 Comparison of Direct and Indirect Impacts

Resource Alternative A Alternative B1 No Action Alternative

Topography

After reclamation, impacts 

to topography would be 

negligible.

Same as Alternative A. Same as Alternative A.

Air and Climate 

Resources

Direct mining criteria 

emissions

Negligible impact on 

Colorado (0.002 to 

0.79%) and U.S. (0.00002 

to 0.01%) emissions. 

Moderate to high impact 

on regional emissions 

(0.02 to 19.6%), but region 

would remain in 

attainment. 

Negligible impact on 

Colorado (0.001 to 0.46%) 

and U.S. (0.00001 to 

0.01%) emissions. 

Moderate to high impact on 

regional emissions (0.01 to 

9.8%), but region would 

remain in attainment.

Impacts would be 

negligible and less than 

those under either 

Alternatives A or B.

Direct GHG2 emissions

Negligible impact on 

Colorado (0.25%) and U.S. 

(0.014%) total annual 

GHG emissions.

Negligible impact on 

Colorado (0.06%) and U.S. 

(0.003%) total annual GHG 

emissions.

Impacts would be 

negligible and less than 

those under either 

Alternatives A or B.

Indirect coal combustion 

criteria emissions

Negligible indirect impact 

on U.S. (0.00029 to 

0.1428%) National 

Emissions Inventory. 

Moderate indirect impact 

on total Colorado (0.02 to 

8.63%) and moderate to 

high regional (0.1 to 

118.3%) emissions, but 

region would remain in 

attainment.

Negligible indirect impact on 

U.S. (0.00019 to 0.095%) 

National Emissions 

Inventory. Moderate indirect 

impact on total Colorado 

(0.01 to 5.75%) and 

moderate to high regional 

(0.05 to 78.8%) emissions, 

but region would remain in 

attainment.

Impacts would be similar 

to Alternatives A or B, 

because the generating 

stations would likely 

continue to burn coal at 

the same rate but using 

coal from elsewhere.

Indirect combustion GHG

emissions

Negligible indirect impact 

on U.S. (0.231%) and 

global (0.048%) annual 

GHG emissions.

Negligible indirect impact on 

U.S. (0.071%) and global 

(0.015%) annual GHG 

emissions.

Impacts would be similar 

to Alternatives A or B, but 

the generating stations 

would likely continue to 

burn coal at the same rate 

but using coal from 

elsewhere. Emissions 

changes would be 

dependent on the alternative 

coal combusted. 

Indirect coal combustion 

mercury deposition 

impacts

Minor percentage (8.3%) 

of the total mercury 

generated in Colorado.

Negligible to minor 

percentage (3.4%) of the 

total mercury generated in 

Colorado.

Impacts would be 

negligible similar to 

Alternatives A or B, but 

the generating stations 

would likely continue to 

burn coal at the same rate 

but using coal from 

elsewhere.

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 4-3 

Mining Plan Modification Environmental Assessment
Chapter 4 – Environmental Consequences

Resource Alternative A Alternative B1 No Action Alternative

Ozone Ozone NAAQS would not 

be exceeded. Same as Alternative A.

Impacts would be 

negligible and less than 

those under either 

Alternatives A or B.

Geology

Negligible to minor, longterm impact on the 

geological column.

Negligible impacts. Same as Alternative B.

Water Resources

Hydrologic balance No change. Same as Alternative A. Same as Alternative A.

Water withdrawal and 

transport

Negligible direct impact to 

Yampa River water 

quantity. No impact 

related to transport.

Negligible indirect impact 

to Yampa River water 

quantity from Craig 

Generating Station. No 

impact related to 

transport

Same as Alternative A

Same as Alternative A, but 

impacts would immediately 

cease.

Surface water quality Negligible to minor 

increase in TDS3. Same as Alternative A. Same as Alternative A.

Groundwater impacts Negligible impacts to 

groundwater. Same as Alternative A. Same as Alternative A.

Indirect iron, mercury, 

and selenium impacts from 

coal combustion

Negligible iron loadings.

Incremental but 

unquantifiable addition to 

baseline mercury 

concentrations.

Incremental but 

unquantifiable addition to 

baseline selenium 

concentrations.

Same as Alternative A. Same as Alternative A.

Indirect coal combustion 

impacts to groundwater

Negligible indirect impact 

to groundwater related to 

CCRs4

. 

Less than Alternative A

but still negligible. 

Less than Alternatives A 

or B but still negligible. 

Vegetation

Short-term to major 

impacts until reclamation 

replaced vegetation to 

approved reclamation plan

(or improved) conditions. 

Reclamation would 

replace 1,181 acres of 

previously disturbed 

vegetation; areas that are 

already reclaimed would 

continue to proceed 

through natural succession 

or management under 

future land uses.

Negligible impacts until 

reclamation replaced 

vegetation to approved 

reclamation plan (or

improved) conditions. 

Reclamation would 

replace 809 acres of 

previously disturbed 

vegetation; areas that are 

already reclaimed would 

continue to proceed 

through natural succession 

or management under 

future land uses.

No additional extraction 

related disturbance to 

vegetation would occur. 

Reclamation would 

happen sooner and would 

replace vegetation to 

approved reclamation plan

(or improved) conditions

on 789 acres of previously 

disturbed vegetation; 

areas that are already 

reclaimed would continue 

to proceed through 

natural succession or 

management under future 

land uses. 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 4-4 

Mining Plan Modification Environmental Assessment
Chapter 4 – Environmental Consequences

Resource Alternative A Alternative B1 No Action Alternative

Wetlands Negligible impacts to 

wetlands after mitigation. No impact to wetlands. No impact to wetlands.

Fish and Wildlife

Big game

Short-term minor to 

moderate impact on game 

range until reclamation 

replaced habitat to 

approved reclamation plan 

(or improved) conditions. 

Negligible impacts until 

reclamation replaced 

habitat to approved 

reclamation plan (or 

improved) conditions.

No impacts. Reclamation 

would replace habitat to 

approved reclamation plan 

(or improved) conditions.

Migratory birds, raptors, 

reptiles, and amphibians

Negligible to minor 

impacts. Negligible impacts. Negligible impacts.

Fisheries

No direct impacts to 

fisheries. See Special 

Status Species below for 

indirect effects to 

Colorado River fish.

Same as Alternative A. Same as Alternative A.

Special Status Species

Impacts to state-listed and 

sensitive species would be 

short term and negligible to 

moderate until successful 

reclamation, when 

reclamation goals would 

prioritize the replacement of 

wildlife habitat.

Impacts to the Colorado 

River fish from mercury and 

selenium impacts would be 

moderate. Impacts to the 

yellow-billed cuckoo would 

be minor. Research and 

funding proposed as 

mitigation would offset 

adverse impacts.

Impacts to state-listed and 

sensitive species would be 

the similar to Alternative A, 

but the additional 

disturbance under 

Alternative B is unlikely to 

change any impacts from 

their current levels due to 

the limited amount of 

additional acres involved.

Impacts to the Colorado 

River fish and yellow-billed 

cuckoo would be similar to 

Alternative A. However, as 

less Colowyo coal would be 

combusted, the adverse 

impacts would be reduced 

accordingly.

Same as Alternative A.

Cultural and Historic 

Resources No impacts. Same as Alternative A. Same as Alternative A.

Indian Concerns No impacts. Same as Alternative A. Same as Alternative A.

Socioeconomics

Moderate to major, shortterm (two years) 

beneficial impacts related 

to annual payroll, 

insurance, retirement, 

local expenditures, taxes, 

and royalty payments.

Same as Alternative A, but 

a greater (~$70 million) 

contribution to the local 

economy than Alternative 

A due to two years longer 

mine life.

Immediate economic loss 

to the local community 

would be at least $70

million when compared to 

Alternative A and 

approximately $140

million when compared to 

Alternative B.

Visual Resources

Minor short-term and 

long-term impacts that 

would still meet Class IV 

objectives.

Same as Alternative A. Same as Alternative A.

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 4-5 

Mining Plan Modification Environmental Assessment
Chapter 4 – Environmental Consequences

Resource Alternative A Alternative B1 No Action Alternative

Recreation

Negligible to minor, shortterm impacts to 

recreation until 

reclamation.

Same as Alternative A. Same as Alternative A.

Paleontology

The significance of the 

potential damage and 

removal of fossils during 

removal of the geological 

column, as well as the 

beneficial impact of 

increasing the potential for 

discovery of scientifically 

significant fossils, would 

depend upon the 

significance of the fossil.

Same as Alternative A, but 

due to the lesser removal of 

the geological column the 

potential impacts would be 

less. 

No impacts.

Access and 

Transportation

Minor, short-term 

increase in traffic due to 

increased production rate.

No impacts. No impacts.

Solid or Hazardous 

Waste No impacts. No impacts. No impacts.

Noise

Minor, short-term 

increase in noise due to

increased production rate. 

It is unlikely the increased 

noise would reach 

residences located near 

the Project Area 

boundary.

No change in noise, but 

the current noise levels 

would extend two years 

longer than under 

Alternative A.

Noise levels would 

decrease substantially.

Livestock Grazing

Negligible to moderate, 

short-term impact on the 

availability for grazing.

The impacts on livestock 

and grazing would be the 

same as those under 

Alternative A, but grazing 

would be reinstated 2 

years later than under 

Alternative A.

Grazing would be 

reinstated four or two 

years earlier than under 

Alternatives A or B, 

respectively.

Soils

Negligible impacts related 

to erosion and fertility 

loss.

Same as Alternative A. Same as Alternative A.

Alluvial Valley Floors No impacts. No impacts. No impacts. 1 Only the potential impacts are discussed in this table, not the previous impacts that have occurred since 2007. 2 greenhouse gas, 

3 total dissolved solids, 

4 coal combustion residues

5 greater sage-grouse

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 4-6 

Mining Plan Modification Environmental Assessment
Chapter 4 – Environmental Consequences

4.2 TOPOGRAPHY

4.2.1 Alternative A – Proposed Action, PR02 as Approved in 2007

Impacts to topography would occur to 1,181 acres of previously undisturbed land within the 

Project Area. Under Alternative A, the East Taylor permanent valley fill would be constructed 

to an elevation of 8,050 feet amsl. The West Taylor permanent valley fill would be constructed 

to an elevation of 8,400 feet amsl. The East Taylor temporary spoil pile would be constructed 

east of the East Taylor permanent valley fill, to an elevation of 8,300 feet amsl. The West 

Taylor temporary spoil pile would be constructed on top of the East Taylor permanent valley 

fill to an elevation of 8,300 feet amsl. As part of reclamation, the pit would be backfilled using 

the overburden stored in the temporary spoil piles. All areas previously disturbed would be 

backfilled and graded to their approved post-mining topographies, surfaces would be 

recontoured to their approved conditions, and surface drainage patterns would be established

per the approved reclamation plan. The final surface configuration (Post-mining Topography 

Map [Map19B], Appendix B) also would provide topographic relief for wildlife habitat. The 

regrading plan would re-establish escape cover, south facing slopes for wintering big game 

populations, and small drainages suitable as future location of stock ponds necessary to achieve 

the post-mining land use. After reclamation has been completed, the impacts to topography 

would be negligible.

4.2.2 Alternative B – PR02 as Revised 

4.2.2.1 Previous Impacts

Impacts to the local topography have already occurred on 789 acres within the Project Area

since 2007. The new disturbance consists of the South Taylor open pit, the West Taylor valley 

fill, a portion of the East Taylor valley fill, the East Taylor and West Taylor temporary spoil 

piles, and topsoil stockpiles. The East Taylor permanent valley fill is constructed to an elevation 

of 7,990 feet amsl. The West Taylor permanent valley fill is constructed to an elevation of 

7,950 feet amsl. The West Taylor temporary spoil pile is complete and constructed to 8,200 

feet amsl in elevation. The South Taylor open pit has lowered the overall elevation in this 

location. Conversely, the valley fill facilities, temporary spoil piles, and topsoil stockpiles have 

increased the elevation in these locations. Approximately 66 acres have been reclaimed to 

date, which has established the approved post-mining topography on this portion.

4.2.2.2 Potential Impacts

Under Alternative B, there would be approximately 20 acres of additional disturbance in 

addition to the previous impacts. This disturbance would occur on the west side of the South 

Taylor pit and the West Taylor valley fill. The East Taylor temporary spoil pile would become 

slightly taller during mining as a result of the addition of up to 1,030,000 cubic yards of material. In 

general, the impacts to topography would be similar to those under Alternative A. After 

reclamation has been completed, the impacts to topography would be negligible.

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 4-7 

Mining Plan Modification Environmental Assessment
Chapter 4 – Environmental Consequences

4.2.3 No Action Alternative

Under the No Action Alternative, mining would cease and closure and reclamation would be 

initiated. The temporary spoil piles would not increase in elevation but would stay at their

current elevations until reclaimed. The impacts to topography under closure and reclamation 

would be similar to those under Alternatives A and B but would occur earlier. After 

reclamation has been completed, the impacts to topography would be negligible.

4.2.4 Mitigation Measures

No mitigation measures would be necessary for topography.

4.3 AIR AND CLIMATE RESOURCES 

4.3.1 Alternative A - Proposed Action, PR02 as Approved in 2007

4.3.1.1 Direct Mining Criteria Pollutant Impacts 

All emission sources are divided into three primary categories: fugitive emissions, process 

emissions, and tailpipe emissions. Fugitive emissions include excavation, haulage, and 

reclamation activities. Process emissions are associated with loading and unloading of coal to 

hoppers or haul trucks, primary and secondary crushing, conveying to storage areas, railcar 

loading, and rock crushing and screening. Tailpipe emissions are associated with mine vehicles.

In-Pit Fugitive Emissions Sources

Within the South Taylor pit there are numerous mining activities that contribute to fugitive 

particulate emissions, including shovels, a dragline, front end loaders (FELS) for overburden and 

coal, and drilling. Fugitive emissions, including particulate and NOX, also occur from the use of 

explosives for blasting to break apart overburden for removal. Mobile sources consist of dozers 

(both overburden and coal), graders, water trucks, and haul trucks. Maximum emission 

estimates assumed that no reclamation was occurring at the South Taylor pit; thus increasing 

the mining rate to its capacity.

The pit areas have a blasting component associated with them. Blasting at the mine currently is 

limited to 152,000 pounds or 76 tons of explosive material, per day. The mine has submitted a 

revision to their air quality permit to increase their current blasting limit to 700,000 pounds per day, 

but that is still under review. 

Other Fugitive Sources

The mine has several coal piles throughout their property all of which can contribute to fugitive 

emissions due to windblown dust. Also, dozers are utilized on all coal piles at various times. 

Particulate emissions are also attributable to travel on both paved and unpaved haul roads, and 

traffic in the boneyard, maintenance parking lot and maintenance area.

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 4-8 

Mining Plan Modification Environmental Assessment
Chapter 4 – Environmental Consequences

Process Emission Sources

Colowyo utilizes a primary and secondary coal crushing facility. Each crusher contains multiple 

sources of particulate emissions. Loading of coal into hoppers, the practice of crushing the 

coal, conveying into storage bins, and loading into dump trucks are all sources of emissions. 

Loading coal onto railcars for transport contributes to overall particulate emissions. The mine 

also has a rock crushing and screening operation.

Tailpipe Emissions Sources 

The mine contains a 1.4 mile (2.3 km) paved access road and 3.7 mile (6.0 km) paved haul road. 

The access road is primarily used by employees coming to and from the mine using typical 

passenger vehicles and occasional delivery trucks. The paved haul road is used by all trucks 

hauling coal as well as employee vehicles and occasional delivery trucks. To be conservative 

with this analysis, all vehicles are assumed to travel the entire length of the road each trip, 

which may lead to an over-estimate of the emissions generated. Maximum emission estimates 

assume an equivalent of 125 cars, 75 trucks, and 25 delivery vehicles per day for 305 operating 

days per year. The equivalent number of 50T haul trucks per day is 1,077. The larger 240T 

truck emissions are calculated based on distance traveled within each appropriate pit, the spoil 

piles, and haul distances to the R1and R4 coal stockpiles. 

Water trucks, scrapers, graders, and dozers are assumed to release tailpipe emissions within 

the pits, the exception being the dozers operated on the G1/G2 and R1and R4 stockpiles.

Hazardous Air Pollutant Emission Estimates

HAP is defined in 40 CFR part 61 as a pollutant that causes or may cause cancer or serious 

health effects such as birth defects. There are currently 187 listed HAPs

(http://www.epa.gov/ttnatw01/188polls.html). 

The action of combustion results in the emission of some HAPs. Similar to other gaseous 

pollutants associated with the mine, HAPs are a result of tailpipe emissions, blasting, and drilling 

activities. Diesel equipment engine characteristics, including make and model, were used to 

establish emissions for graders, scrapers, and dozers. Fuel consumption rates were utilized to 

determine drilling HAP emissions. 

Combustion HAP emission factors for on-road vehicles are based on VOC emissions. 

Appropriate mass fractions were applied to VOC emission factors for on-road vehicles to 

obtain each HAP factor, based on EPA’s published findings regarding the speciation of toxic 

VOCs and polycyclic aromatic hydrocarbons (PAH) associated with haul trucks pre and post 

2007 (MOVE 2014). Blasting emission factors were based on Amatol (50% ANFO and 50% 

TNT) from the EPA Open Burn/Open Detonation Dispersion Model database.

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 4-9 

Mining Plan Modification Environmental Assessment
Chapter 4 – Environmental Consequences

4.3.1.2 Alternative A Direct Emission Calculations

Utilizing the assumptions and processes described above, emissions were calculated for criteria 

pollutants and HAPs (Table 4.3-1).

Table 4.3-1 Criteria Pollutant and HAP Emission Estimates (tpy), Alternative A

Source PM10 PM2.5 NOx CO VOC SO2 HAPs

Fugitive 2,286 262 1,736 10,975 0.4 1.0 2.6E-03

Process 8.0 1.1 0 0 0 0 0 

Tailpipe 3.6 3.1 149 216 72 0.2 9.1

Total 2,298 266 1,885 11,191 72 1.2 9.1 

When comparing gaseous criteria pollutants to state and national totals from the 2011 National 

Emissions Inventory (NEI)

5

, Alternative A would have a negligible impact. On a percentage 

basis, Alternative A would range from 0.002 percent to 0.79 percent when compared to state 

totals; SO2 would be the lowest and CO emissions would be the largest. On a national scale 

the percentage relative to the NEI would range from 0.00002 percent to 0.02 percent. SO2, 

again, would contribute the least, and CO would have the highest percentage. All contributions 

would be insignificant in comparison. A more regional comparison of gaseous pollutants to 

four surrounding counties was also conducted. These counties included Garfield, Moffat, Rio 

Blanco, and Routt. Comparisons would range from 0.2 percent to 19.6 percent.

Particulate emissions would be similar. With fugitive emissions included, Alternative A would 

contribute 0.26 percent of the statewide PM2.5 emissions; with fugitive emissions excluded that 

percentage would decrease to 0.00004 percent. PM10 emissions associated with Alternative A 

would be 0.70 percent and 0.00004 percent of the statewide total with fugitive emissions 

included and excluded, respectively. National percentages would be even less at 0.01 percent 

and 0.004 percent. Direct particulate emissions associated with Alternative A would be 

insignificant in comparison to Colorado and nationally. The surrounding county comparison 

showed that Alternative A would be a maximum of 10.3 percent of the region’s particulate 

emissions.

The county maximum HAPs comparison of Alternative A would be 10.5 percent of the EPA 

2011 NEI. The maximum HAPs emissions contributed by Alternative A would be 0.005 

percent of the total HAPs emitted by the State of Colorado per the EPA 2011 NEI. Nationally, 

9.05 million tons of HAPs were emitted in 2001 and Alternative A would contribute 0.0001 

percent. The amount attributed to Alternative A would be insignificant by comparison. 

While there would be a moderate to high contribution of emissions from Alternative A to the 

region, the surrounding AQCR has consistently maintained its designation of attainment. 

Monitoring data from 2007 to 2014 support this designation (Section 4.3.2.4). 

5 The NEI is a comprehensive estimate of air emissions from all air emission sources in the U.S.

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Chapter 4 – Environmental Consequences

Direct Greenhouse Gas Emission Estimates 

Direct GHG emissions sources from onsite mining are in two main categories: the emissions 

(methane) released by the exposure of the coal seams to the atmosphere and the combustion 

emissions from mining equipment. The combustion emission component includes gaseous 

emissions and particulate emissions (black carbon). Each component is described in the 

following sections. 

Methane Emissions from Coal Extraction

Methane (CH4) is the predominant GHG emitted from direct surface coal extraction and postextraction handling of coal. Documents developed by the EPA in collaboration with the Russia 

Coalbed Methane Center were used for determining methane emissions from coal mining and 

handing. The final methods used are included in the Intergovernmental Panel on Climate 

Change (IPCC) Guidelines (Irving unknown date). One approach is the Tier 1 approach or 

Global Average Method. It requires the use of emission factors-based characteristics of coal 

from regional studies. It should be used when basin specific data is unavailable. Tier 2 is the 

“Country or Basin Specific Method”. Both methods are recommended by the IPCC for surface 

mining estimates.

A Tier 2 methodology was used to determine methane emissions estimates from extraction for 

both Alternative A and Alternative B. In addition to methane estimates from coal extraction, 

post-mining estimates were also determined. Tier 2 methodologies were used because 

emission factors associated with Rocky Mountain coal were available.

Alternative A assumes 6 mtpy (5.44 million metric tons [mmt]). The IPCC has supplied default 

emission factors for surface mining with a range of 0.3 to 2.0 m3 CH4/metric ton (mt) of coal. 

Basin specific factors are derived from the in-situ factors, which are based on geologic regions 

of the U.S. The Colowyo Mine falls into the Rocky Mountain region with an in-situ basin 

methane emission factor for coal of 0.4 m3 CH4/mt. The second component of total surface 

mining methane emissions is the methane content of the surrounding strata. Total surface 

mining emissions typically produce twice as much methane as in-situ coal (EPA 2006). The 

surrounding strata are assumed to also have an emission factor of 0.4 m3 CH4/mt resulting in a 

total factor of 0.8 m3 CH4/mt. A factor of 0.67 Gg/106

 m3 was implemented as part of the 

conversion from cubic meters to metric tonnes. 

Post-mining coal handling also contributes to overall methane emissions. Again, the in-situ 

emission factor is applied, but, to avoid overestimates, only the percentage of gas released is 

included in the calculation. On average, western U.S. coal retains 72 percent of the methane 

(Kirchgessner et al. 1996). Therefore, 28 percent is released during the post-mining handling 

process. 

After aggregating the two processes (extraction and post-mining) and assuming 5.44 mmt/year 

coal extraction, the total methane emitted is 3,326 metric tonnes annually. Additionally, the 

extraction of all 41.7 mmt (43 million short tons) would generate approximately 26,275 metric 

tonnes of methane.

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 4-11

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Chapter 4 – Environmental Consequences

Mining Combustion Gaseous GHG Emissions 

The EPA regulates several GHGs which primarily include CO2, CH4, and nitrous oxide (N2O). 

There are several other regulated GHGs, such as refrigerants, that are not emitted by the mine. 

CO2, CH4, and N2O are byproducts of incomplete combustion and are emitted via tailpipe, 

blasting, and drilling. Each regulated GHG has an associated global warming potential (GWP). 

GWP was developed to allow for direct comparisons of global warming impacts of different 

gases. CO2 is used as the reference gas and therefore has a GWP of 1. According to the EPA, 

CH4, and N2O have GWPs over 100 years of 25 and 298, respectively. All associated GHG 

emissions are multiplied by each applicable GWP and aggregated together to obtain a final value 

of CO2e in units of metric tons.

Utilizing EPA emissions factors and the maximum mining rate of 6 mtpy, the direct GHG 

emissions associated with Alternative A are detailed Table 4.3-2. In 2011, 2,245 mmt of CO2e 

were emitted throughout the U.S. according to the EPA NEI database. Also, 130 mmt were 

emitted within Colorado as stated by the 2014 Colorado Greenhouse Gas Inventory Update. 

Alternative A would contribute 0.25 percent of the statewide total and 0.014 percent 

nationwide. In comparison, the amount associated with Alternative A would be insignificant. 

The emissions contributable to Alternative A would be much smaller when compared to the 

statewide and national GHG emissions.

Black Carbon Emission Estimates

Black carbon is a significant component of particulate emissions related to incomplete 

combustion. Haul trucks and locomotive use of diesel fuel are sources of black carbon. As of 

2005, 93 percent of all mobile source emissions came from diesel engines (EPA 2012). Black 

carbon directly absorbs light and reduces the reflection of heat off snow and ice as it gets 

deposited. Black carbon has been linked to climate impacts such as increased temperatures and 

accelerated ice and snow melt.

All haul truck types were evaluated for their contribution of black carbon as a percentage of 

overall particulate (Table 4.3-3). All 240T trucks were assumed 830E Komastu haul trucks 

which all have a “2007-plus” engine. 50T haul trucks are “pre-2007” engines. The EPA has 

determined black carbon to be a higher percentage of particulate matter when emitted from 

engines constructed prior to 2007. There is a drastic reduction for newer engines because of 

better design and use of diesel particulate filters (DPFs). The carbon black percentage of pre2007 trucks is 78.97 percent compared to 9.98 percent for post-2007 trucks (MOVE 2014). 

Passenger vehicles also contribute to black carbon emissions, but it is approximately an order 

of magnitude less. 

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Table 4.3-2 Direct GHG Emissions (metric tpy), Alternative A

Activity CO2 CH4 N2O CO2e 

Scrapers 3,756 0.21 0.10 3,792

Drills 1,973 0.08 0.02 1,980

Dozers 59,236 3.31 1.62 59,801

Graders 33,344 1.87 0.91 33,662

Haul Truck (240T) 28,390 0.01 0.01 28,393

Water Trucks 14,488 0.01 0.01 14,493

Blasting 84,106 2.97 0.79 84,417

Haul Coal to Crusher (50T) 11,891 0.01 0.01 11,895

Access Road 83 0.005 0.01 86

Rail Maintenance 546 0.80 1.98 1,156

Methane Release -- 3,326 -- 83,150

Total 237,813 3,335 5.46 322,823 1 All water trucks use the same engine as the 793C haul trucks; assumes 10 

mph speed 

2 Blasting assume 400 tons of ANFO per blast 3 Assumes an average of 25 gal/hr fuel consumption from Caterpillar 

Performance Handbook edition 42 - D-11 T tractors medium consumption 

rate

4 Assumes an average of 15 gal/hr fuel consumption from Caterpillar 

Performance Handbook edition 42 - 24 M graders medium consumption rate 5 Assumes an average of 24 gal/hr fuel consumption from Caterpillar 

Performance Handbook edition 29 - 637E scrapers medium consumption rate; 

also average speed of 8 mph

6 Assumes an average of 50 gal/hr fuel consumption from Komatsu Application 

Handbook Edition 30 - 830E haul truck high consumption rate; also average 

speed of 25 mph (real time fleet data)

7 Weststar 6900XD; average speed of 25 mph; 120 gallon tank assumed to be 

filled after each 10 hr shift - 12 gal/hr fuel consumption 8 Assumes 1200 gal diesel consumed per day; 800 maximum holes drilled per 

day

Table 4.3-3 Black Carbon Emissions (tpy) from Haul Trucks, Alternative A

Haul

Truck

Black Carbon 

PM2.5

Black Carbon 

PM10

50 Ton 0.131 0.154

240 Ton 0.095 0.104

Access Road 7.15E-04 7.73E-04

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 4-13

Mining Plan Modification Environmental Assessment
Chapter 4 – Environmental Consequences

4.3.1.3 Air Quality Environmental Controls for Direct Emissions from the Mine

Roads

Colowyo employs a dust suppression program for in-pit roads and other unpaved roads, which 

primarily involves periodic watering. As needed, mine water trucks spray water along the 

roadway to mitigate dusty conditions. During the dryer months of the year, the water trucks 

wet down active roadways a minimum of two or three times per shift. If watering of the 

roadways is not adequate to control dust, a chemical dust suppressant may be applied to the 

primary in-pit roads to aid in dust suppression during the dryer months. Colowyo surfaces inpit roads with crushed rock; in-pit roads would not be paved with asphalt. The out-of-pit haul 

roads are paved with asphalt to provide for dust control.

A strict speed control is implemented for all roads to control dust and to provide for safe 

operation of the equipment. Travel of unauthorized vehicles is prohibited on the mine property, 

and overburden haul equipment is restricted to roads with appropriate capacity and structure 

for the equipment size and weight. In addition, most haul road embankment slopes and 

adjacent areas are mechanically stabilized and seeded with a reclamation seed mixture. 

Mechanical stabilization consists of furrowing, chiseling, "cat tracking", and mulch, depending on 

accessibility to the slopes, and prevents dust formation from erosion and wind exposure.

Coal Crushing Facility

The coal crushing and conveying operations at the primary crusher and the Gossard loadout 

have been equipped with water spraying systems at all coal transfer points. Water sprays have

been installed at the primary crusher to prevent excessive dust emissions. The secondary 

crusher at the Gossard Loadout has a baghouse to control coal dust emissions. A stacking tube 

with metal doors is also used to minimize coal dust emissions at the 100,000-ton crushed coal 

stockpile. These air quality control measures at the coal crushing handling and loadout facilities 

have been approved by the CDPHE.

Colowyo maintains several areas for coal storage near the in-pit crusher and also near the 

Gossard Loadout. Inactive storage piles have been sloped and compacted to prevent wind 

erosion and spontaneous combustion. If coal dust becomes a problem in the active coal

storage piles, a mobile water truck with a high pressure pump and nozzle is available for dust 

suppression. 

Disturbance 

Colowyo, to the extent practical, minimizes the area of land disturbed at any one time. Topsoil 

is removed only to the extent necessary to accommodate the mining operations. The rehandling of both topsoil and spoil material is kept to a minimum. Reclamation of disturbed 

areas commences as contemporaneously as possible. As necessary, a mobile water truck is 

assigned to work in topsoil or spoil removal areas to keep any dusty conditions under control.

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 4-14

Mining Plan Modification Environmental Assessment
Chapter 4 – Environmental Consequences

4.3.1.4 Indirect Combustion Criteria Impacts

The number and location of coal customers for the mine has varied annually and over time. 

Coal is a commodity, and the use of the coal from the mine would depend on a number of 

factors including demand, price, quality, and transportation, among others. 

Colowyo has historically provided coal to a variety of end users, both regionally and nationally. 

Since 1977 (the beginning of coal sales records), Colowyo has provided coal to approximately 

ninety different end users all over the nation. In recent years (2009 to present), Colowyo has 

sold between 66 percent and 99 percent of their coal to the Craig Generating Station. The 

average annual sales to the Craig Generating Station between 2007 and 2014 were 2.3 mtpy. 

This represents approximately 48 percent of the 4.8 mtpy required for the Craig Generating 

Station’s annual average combustion needs.

The trend towards supplying coal exclusively to the Craig Generating Station seen in the 2007 

to present timeframe is a deviation from historical coal sales within which Colowyo sold coal to 

a much wider array of end users. Although ongoing coal sales to the Craig Generating Station 

is likely to continue in the future, with increased coal mining rates as proposed under 

Alternative A, the relative percentage of Colowyo coal being shipped to the Craig Generating 

Station would be reduced and a coal distribution more consistent with the longer historical 

sales record would likely return. 

The mine is connected to a main rail line via a private rail spur that connects to the coal load 

out facility at the mine and runs north to Craig where it intersects with the Moffat Tunnel line. 

The latter line then connects to two east-west rail lines 80 miles (129 km) southeast of Craig in 

Eagle County. Coal heading east of this intersection will pass through the Moffat Tunnel and 

deliver coal to the eastern slope of Colorado. Coal heading west of this intersection will join 

with a major east-west rail line that delivers coal throughout the country.

The mine has an existing contract based on quality of coal (million British thermal units) with the 

Craig Generating Station to which they provide approximately 2.3 mtpy; this contract expires in 

2017. For the reasons listed above, it is difficult to project exactly how much coal from the 

mine would be burned at any particular power plant at any given time in the future. 

In addition to the reasonably foreseeable combustion of coal at the Craig Generating Station, 

coal provided by the mine is particularly economically viable for regional generating facilities 

due to the reduced cost of transport. As a result, the Hayden Generating Station is also a 

reasonably foreseeable future user of coal from the Colowyo Mine. Using the Craig and 

Hayden Generating Stations as reasonably foreseeable locations for the combustion of coal 

produced at the mine, criteria pollutant emissions from coal combustion at these facilities 

(Table 4.3-4) can be used to calculate emissions associated with coal from the Colowyo Mine. 

Power plant emissions are analyzed and regulated by state and tribal governments to determine 

whether impacts will cause or contribute to violations of federal and state/tribal ambient air 

quality standards. Federal and state rules for power plant emissions address hazardous and 

toxic air pollution from power plants to protect public health and the environment. 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 4-15

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Chapter 4 – Environmental Consequences

Table 4.3-4 Reporting Year 2014 Criteria Emissions Data

Facility 2014 (reporting year) Annual Actual 

Pollutant Emissions (tpy) 

PM10 PM2.5 CO NO2 SO2 VOC

Craig Generating 

Station 172.2 121.1 1232.8 12091.0 3261.0 62.2

Hayden Generating 

Station 148.3 67.5 385.1 6483.6 2330.7 49.2

Source: APENS

The maximum coal produced under Alternative A would be 6 mtpy, so this maximum 

production was used to conservatively estimate annual criteria pollutant emissions (Table 4.3-

5). Emissions were also calculated for the current maximum contracted coal tonnage. These 

rates may vary significantly from year to year, but are useful for determining a general estimate 

of criteria pollutant emissions. Emissions are calculated based on the highest regional emission 

rate (regional maximum), the average regional emissions rate (regional average), and using the 

Craig Generating Station emissions factors.

Table 4.3-5 Predicted Criteria Emissions Data Based on Regional Maximum, 

Average, and Craig Generating Station Only Emissions Rates

Emissions 

Method

Coal 

Combustion 

Rate (tpy) 

PM10

(tpy) 

PM2.5 

(tpy CO (tpy) NO2 (tpy) 

SO2

(tpy) 

VOC 

(tpy) 

Regional Maximum

Maximum Mining 6,000,000 507.58 231.15 1817.16 22,196.57 7,979.14 168.44

Contracted Rate 2,300,000 194.57 88.61 696.58 8,508.69 3,058.67 64.57

Regional Average

Maximum Mining 6,000,000 380.72 204.81 1567.78 20,009.44 6,392.95 130.05

Contracted Rate 2,300,000 145.94 78.51 600.98 7670.28 2,450.63 49.85

Craig Generating Station Only

Maximum Mining 6,000,000 253.85 178.47 1,817.16 1,7822.30 4,806.76 91.67

Contracted Rate 2,300,000 97.31 68.41 696.58 6831.88 1,842.59 35.14

The Hayden Station emission rates produce the highest PM10, PM2.5, SO2, VOC, and NOx 

emission rates of the two facilities while the Craig Generating Station had the highest emission 

rate for CO. Table 4.3-6 presents the relative percentage of the 2011 EPA NEI for Colorado 

that the predicted emissions represent. Emissions for all sources in Colorado were compared 

to the emissions presented above. 

Emissions at the maximum mining rate would range from 0.02 percent to 8.63 percent of the 

Colorado total NEI emissions and from 0.03 percent to 14.33 percent based on regional 

maximum emissions calculations (Table 4.3-6). It should be noted that these values are highly 

conservative and would exceed the annual coal combustion rate at either the Craig or Hayden

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 4-16

Mining Plan Modification Environmental Assessment
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Generating Stations which are approximately 4.8 and 2.0 mtpy, respectively. Emissions at the 

maximum mining rate would range from 0.00029 percent to 0.1428 percent of the national 

total NEI emissions and from 0.00016 percent to 0.115 percent based on regional maximum 

emissions calculations (Table 4.3-6). The emissions would be insignificant relative to the 

national emissions totals and moderate emissions relative to the Colorado emissions total. 

Emissions at the maximum mining rate when compared to the four surrounding counties would 

range from 0.1 percent to 118.3 percent. As stated above, the assumed 6.0 mtpy is a very 

conservative combustion rate and not representative of current rates at either generating 

station. Emissions under the contracted rate of 2.3 mtpy would range from 0.1 percent to 45.3 

percent of the surrounding county total emissions. These would be substantial contributions 

associated with the two generating stations, but the regional designation regarding NAAQS 

compliance would not change and remain in attainment. As described in Section 4.3.2.4, the 

state monitoring network has shown compliance with the NAAQS when natural exceptional 

events are excluded.

Table 4.3-6 Predicted Criteria Emissions Data Based on Regional Maximum, 

Average, and Craig Generating Station Only Emissions Rates

Emissions 

Method

Coal 

Combustion 

Rate (tpy) 

PM10 (% 

of 2011 

NEI)

PM2.5 

(% of 

2011 

NEI)

CO (% 

of 2011 

NEI)

NO2

(% of 

2011 

NEI)

SO2 (% 

of 2011 

NEI)

VOC 

(% of 

2011 

NEI)

Regional Maximum

Maximum Mining 6,000,000 0.15 0.23 0.13 7.30 14.32 0.03

Contracted Rate 2,300,000 0.06 0.09 0.05 2.80 5.49 0.01

Regional Average

Maximum Mining 6,000,000 0.12 0.20 0.11 6.58 11.47 0.02

Contracted Rate 2,300,000 0.04 0.08 0.04 2.52 4.40 0.01

Craig Only 

Maximum Mining 6,000,000 0.08 0.18 0.13 5.86 8.63 0.02

Contracted Rate 2,300,000 0.03 0.07 0.05 2.25 3.31 0.01

Indirect Coal Combustion GHG and Climate Change Impacts

In 2010, in an attempt to assess GHG emissions on a facility, regional and national level, the 

EPA introduced the Greenhouse Gas Reporting Program (GHGRP). The program collects 

GHG data from forty-one source categories. GHGRP data includes direct emissions from large 

stationary sources, accounting for approximately half of total U.S. GHG emissions, and also data 

from suppliers of materials that would result in GHG emissions when those materials are 

burned or released. Most industries began reporting for 2010; additional industries began 

reporting for 2011. The regulations that introduce the GHGRP also provided a standardized 

means to assess and calculate GHG emissions. These calculation methods were codified in 40 

CFR Part 98. For the calculation of combustion emissions the methods are included in subpart 

C of that regulation. These emissions calculations are an approved method for tabulating GHG 

pollutant emissions for the most common GHG pollutants. The emissions are not dependent 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 4-17

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on emissions location or combustion type and provide both speciated and CO2e emissions. 

CO2e is a quantity that describes, for a given mixture and amount of GHG, the amount of CO2

that would have the same GWP, when measured over a specified timescale (generally, 100 

years). CO2e thus reflects the time-integrated radiative forcing of a quantity of emissions or 

rate of GHG emission—a flow into the atmosphere—rather than the instantaneous value of the 

radiative forcing of the stock (concentration) of GHGs in the atmosphere. 

The CO2e for a gas is obtained by multiplying the mass and the GWP of the gas. According to 

EPA, CH4 and N2O have GWPs over 100 years of 25 and 298, respectively. This means that 

emissions of 1 million metric tonnes of methane and nitrous oxide respectively is equivalent to 

emissions of 25 and 298 million metric tonnes of CO2. 

The USEPA provides prepopulated spreadsheets for the calculation of stationary fuel 

combustion, which are based on their approved methodologies for GHG reporting. For 

Alternative A, these spreadsheets were used to assess the total GHG emissions associated with 

combusting the coal produced by the mine both in terms of the maximum annual rate of mining 

and the maximum total coal recovery. 

The following GHG emissions would be generated from the coal mining rates under 

Alternative A (Table 4.3-7).

Table 4.3-7 GHG Coal Combustion Emissions, Alternative A

Coal Combusted 

(Short Tons)

CO2

Emissions 

(metric 

tonnes)

CH4

Emissions 

(metric 

tonnes)

Total 

CH4 in 

CO2e 

(metric 

tonnes)

N2O 

Emission

s (metric 

tonnes)

Total N20 

in CO2e 

(metric 

tonnes)

Total 

CO2e 

(metric 

tonnes)

43,000,000

Proposed 

Total Mine 

Tonnage

 

99,995,227 

 

11,792 

 

294,797 

 

1,715 

 

511,125 

 

100,801,149 

6,000,000

Proposed 

Maximum 

Annual Mine 

Tonnage

 

13,952,822 

 

1,645 

 

41,135 

 

239 

 

71,320 

 

14,065,277 

The values detailed in Table 4.3-7 represent two separate components. The first presents the 

total GHG emission impacts from the combustion of all coal under Alternative A. These 

emission impacts would occur over the life of the mine until 2017. The second represents the 

maximum annual emissions assuming that all mined coal (at the maximum mining rate) is 

combusted in one year.

Based on maximum annual GHG emission impacts, the GHG emissions associated with coal 

combustion under Alternative A would represent 0.048 percent of estimated global emissions 

and 0.231 percent of estimated U.S. net emissions at the maximum mine rate; these emissions 

would be negligible. It should be noted that these rates exceed the historical utilization rate of 

Colowyo coal at the Craig Generating Station and as such exceed the emissions historically 

generated. Finally, given that the causal link between an individual GHG emissions source and 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 4-18

Mining Plan Modification Environmental Assessment
Chapter 4 – Environmental Consequences

global climate change impact is not a direct relationship, the results of these emissions on final 

climate change impacts is unknown.

Regardless of the accuracy of those emission estimates, predicting the degree of impact that any 

single emitter of GHGs may have on global climate change, or on the changes to biotic and 

abiotic systems that accompany climate change, is not possible at this time. No tools or 

scientifically defensible analysis methods exist to describe the degree to which any observable 

changes can, or would be, attributable to Alternative A. As such, the extent of impact that 

emissions resulting from continued mining may have on global climate change, as well as the 

accompanying changes to natural systems, cannot be accurately quantified (US GCRP 2009). 

To provide some additional context, the EPA has recently modeled global climate change 

impacts from a model source emitting 20 percent more GHGs than a 1,500 MW coal-fired 

steam electric generating plant (approx. 14,132,586 metric tons per year of CO2, 273.6 metric 

tons per year of NO, and 136.8 metric tons per year of methane). It estimated a hypothetical 

maximum mean global temperature value increase resulting from such a project. The results 

ranged from 0.00022 and 0.00035 degrees Celsius occurring approximately 50 years after the 

facility begins operation. The modeled changes are extremely small, and any downsizing of 

these results from the global scale would produce greater uncertainly in the predictions. The 

EPA concluded that even assuming such an increase in temperature could be downscaled to a 

particular location, it ''would be too small to physically measure or detect” (Letter from Robert 

J. Meyers, Principal Deputy Assistant Administrator, Office of Air and Radiation re: 

“Endangered Species Act and GHG Emitting Activities [Oct. 3, 2008]). The Project emissions 

are a fraction of the EPA’s modeled source and are shorter in duration, and therefore it is 

reasonable to conclude that the Project would have no measurable impact on the climate.

Although it is impossible to connect a single emitter of GHGs to the degree of impact that 

emitter may have on global climate change, EPA (2015b) has predicted that Colorado will 

experience the following general trends related to climate change:

• The region will experience warmer temperatures with less snowfall.

• Temperatures are expected to increase more in winter than in summer, more at 

night than in the day, and more in the mountains than at lower elevations.

• Earlier snowmelt will result in earlier peak stream flows, weeks before the peak 

needs of ranchers, farmers, recreationalist, and others. In late summer, rivers, lakes, 

and reservoirs will be drier.

• More frequent, more severe, and possibly longer-lasting droughts will occur.

• Crop and livestock production patters could shift northward; less soil moisture due 

to increased evaporation may increase irrigation needs.

• Drier conditions will reduce the range and health of ponderosa and lodge pole pine 

forests, and increase the susceptibility to fire.

• Grasslands and rangelands could expand into previously forested areas.

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• Ecosystems will be stressed and wildlife such as the mountain lion, black bear, longnose sucker, marten, and bald eagle could be further stressed.

Social Cost of Carbon

The EPA and other federal agencies use the social cost of carbon (SCC) to estimate the climate 

benefits of rulemakings. The SCC protocol was also developed for use in cost-benefit analyses 

of proposed regulations that could impact cumulative global emissions (Shelanski and Obstfeld 

2015). The SCC is an estimate of the economic damages associated with an increase in CO2

emissions. This is typically expressed as 1 mt in a single year. This dollar cost figure from this 

calculation represents the value of damages avoided for an associated carbon emissions 

reduction. 

The SCC is meant to be an estimate of climate change damages and includes, but is not limited 

to, changes in net agricultural productivity, human health, and property damages from increased 

flood risk. However, given current modeling and data limitations, it cannot include all damages 

or benefits. 

Based on emission estimates for coal combustion, SCC calculations can quickly rise to large 

values; however, specific threshold levels for the determination of significance can vary 

depending on numerous project factors. NEPA does not require a cost-benefit analysis or the 

presentation of the SCC cost estimates quantitatively. Without a complete monetary costbenefit analysis, which includes the social benefits of energy production, inclusion solely of a 

SCC analysis would be misleading. Therefore, OSMRE did not apply the SCC protocol in this 

analysis. GHG coal combustion emissions are quantified and contextualized against global and 

national GHG emissions above. 

Ozone Precursor Emissions Impacts 

Ozone (O3) can be found in the earth’s atmosphere at both ground level and the upper regions. 

Upper atmospheric O3 is also known as the O3 layer, and protects earth’s surface from the 

sun’s rays. Ground level O3 is the main component of smog and is considered a harmful 

pollutant. 

Ground level O3 is not emitted directly into the air but is created by chemical reactions 

between NOx (NO and NO2) and VOCs in the presence of heat and sunlight (EPA 2015b). 

The most significant chemical reaction driving the formation of ground level O3 is photolysis of 

NO2; however, this process is reversed by the reaction of NO with O3. Therefore, the 

formation of O3 due to NOx is dependent on the NO2 to NO ratio and, by itself, would result 

in very low levels of O3 formation. The net effect of the nitrogen cycle is neither to generate 

nor destroy O3 molecules. Moreover, for O3 to accumulate, an additional pathway is needed to 

convert NO to NO2; one that will not destroy O3. The photochemical oxidation of VOCs, 

such as hydrocarbons and aldehydes, provides that pathway (CARB 2015). When VOCs are 

present, they form radicals which convert NO to NO2 and, thus, increase the formation of O3. 

The relative amounts of VOCs and NOx at a particular location, in addition to climatological 

conditions, will determine whether the NOx behaves as a net O3 generator or a net ozone 

inhibitor. When the VOC/NOx ratio in the ambient air is low, NOx tends to inhibit O3

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formation. In such cases, the amount of VOCs tends to limit the amount of O3 formed, and the 

O3 formation is called "VOC-limited". When the VOC/NOx ratio is high, NOx tends to 

generate O3. In such cases, the amount of NOx tends to limit the amount of O3 formed, and 

O3 formation is called "NOx -limited"(CARB 2015).

Precursors of O3 including NOx and VOCs are generated by both direct and indirect sources. The 

vast majority of precursor emissions are derived from coal combustion and to a lesser degree, onsite 

blasting (as a direct impact of mining). Based on the combustion at the Craig Generating Station 

at either the Alternative A maximum coal mining rate (6 mtpy) as well as at the reasonably 

foreseeable contracted coal combustion rate (2.3 mtpy), conservative estimates of O3

precursors are included in Table 4.3-8. 

Table 4.3-8 Predicted Ozone Precursor Emissions Rates Based on 2013 Craig 

Generating Station Factors and Blasting Emissions, Alternative A

Emissions Method Coal Combustion Rate (tpy) NOX (tpy) VOC (tpy)

Craig Only 6,000,000 17,822.30 91.67

Craig Only 2,300,000 6,831.88 35.14

Blasting Not applicable 1,736.30 0.37

Although O3 precursor emissions from the combustion of coal and onsite blasting can be 

significant, current rates of coal combustion from regional generating facilities and other 

sources of O3 precursors have not resulted in ambient O3 concentrations that have exceeded 

the NAAQS.

Regional O3 NAAQS Compliance

CDPHE provides statewide annual air quality reports for NAAQS comparison and subsequent 

attainment/nonattainment designation. Prior to 2012, Colorado was divided into five multicounty areas that were generally based on topography. These include: the Eastern Plain, the 

north Front Range, the Southern Front Range, the Mountain Counties and the Western 

Counties. The divisions are groupings of monitoring sites with similar characteristics. The area 

most similar and geographically-near the Project Area is the Western Counties. The Western 

Counties generally contain smaller towns located in fairly broad river valleys. Ten counties 

comprise the Western Counties. The counties geographically from north to south are: Moffat, 

Rio Blanco, Garfield, Mesa, Delta, Montrose, San Miguel, Dolores, Montezuma, and La Plata. 

Starting in 2012, Montezuma and La Plata counties were removed and integrated into a new 

monitoring area (Southwestern). The remaining eight counties and Ouray County are now part 

of the Western Slope monitoring area. All annual reports from 2007 to 2014 were evaluated 

for potential regional NAAQS exceedances and/or violations. The 2014 report has not yet 

been completed, but 2014 ozone data was provided by CDPHE. 

Direct combustion rates at both the Craig and Hayden Generating Stations are not proposed 

to change in the foreseeable future. Therefore, the most recent regional monitoring data 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 4-21

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(2014) is representative of Alternative A. Table 4.3-9 outlines the regional O3 concentrations 

at three monitoring sites. The current O3 standard is 0.075 ppm.6

Table 4.3-9 2014 Western Slope Ozone Monitor Concentrations

Ozone 8-hr Avg (parts per million [ppm])

Site Name Location 1st

Maximum

4th

Maximum

3-yr Avg of 4th

Max. (2012-2014)

Garfield County

Rifle 195 14th St. 0.062 0.061 0.063

Mesa County

Palisade Water Treatment 865 Rapid Creek Dr. 0.064 0.062 0.066

Moffat County

Lay Peak 17820 CR 17 0.067 0.062 0.064

O3 standards are based on the 4th high value averaged over a three year period for the 8-hr 

averaging period. For all monitor locations the ambient concentration values indicate that the 

region is in compliance with the O3 NAAQS suggesting that reasonably foreseeable rates of coal 

combustion emissions for Alternative A would not produce exceedances of the NAAQS.

Indirect Mercury Impacts 

Description of Potential Mercury Emissions Generated by Coal Combustion 

In order to describe the total potential mercury emissions that can be generated by mined coal, 

one must have representative data for the quality and characteristics of the coal as well as the 

control strategies and equipment utilized at the final combustion location. In the period from 

2007 to present, Colowyo has provided most of their mined coal to the Craig Generating 

Station. During the period from 2007 to present, the Craig Generating Station has provided 

actual mercury emissions from all onsite atmospheric emission sources via the USEPA’s Toxic 

Release Inventory (TRI) program.

TRI tracks the release of certain toxic chemicals that may pose a threat to human health and 

the environment. U.S. facilities in different industry sectors must report annually how much of 

each chemical is released to the environment and/or managed through recycling, energy 

recovery, and treatment.

Mercury emissions for the Craig Generating Station were reported by the facility for all 

atmospheric emissions sources. Table 4.3-10 presents the actual mercury emissions that 

were reported by the facility.

6 On November 25, 2014, the EPA proposed an updated ground-level O3 standard. Based on scientific evidence, both 

standards would have an average period of eight hours within the 65 to 70 parts per billion (ppb) range.

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Table 4.3-10 TRI Reported Atmospheric Emissions for the Craig Generating 

Station 

Reporting Year Hg Emissions

(lbs/year)

2007 TRI 130

2008 TRI 130

2009 TRI 30

2010 TRI 43

2011 TRI 43

2012 TRI 44

2013 TRI 42.4

Emissions for the Craig Generating Station have changed significantly throughout the period 

from 2007 to 2013. This is a result of the installation of mercury emissions controls at the 

facility.

Using the reported TRI emissions and the coal combusted at the Craig Generating Station 

reported during that period, an emissions factor can be calculated for a pound of mercury per 

ton of coal combusted. Based on the calculated emissions factors mercury emission impacts 

vary significantly between the emissions controls in place in 2007 at the Craig Generating 

Station and the emissions controls in place in 2013. The resultant mercury emissions impacts 

are provided in Table 4.3-11. 

Table 4.3-11 Potential Coal Combustion Mercury Emissions Using Craig 

Generating Station TRI Actual Emissions

Coal 

Production

Emission Factor 

(Derived from 

2007 TRI)

Emission Factor 

(Derived from 

2013 TRI)

Total Predicted 

Hg Emissions

(Derived from 

2007 TRI)

Total Predicted 

Hg Emissions

(Derived from 

2013 TRI)

43 MT (Project 

Total)

2.58292E-05 (lbs/ton 

combusted)

9.20858E-06 (lbs/ton 

combusted) 1,110.65 (lbs Hg) 395.97 (lbs Hg)

6 mtpy

(Maximum 

Annual 

Production)

2.58292E-05 (lbs/ton 

combusted)

9.20858E-06 (lbs/ton 

combusted) 154.98 (lbs Hg/year) 62.24 (lbs Hg/year)

Based on data available from the TRI data explorer, the electrical generation sector in 

Colorado generated approximately 1,070 lbs of mercury emissions for reporting year 2013. 

The Craig Generating Station emissions would represent approximately 5 percent of the state 

mercury emissions if 6 mt of Colowyo coal was combusted in one year. This rate exceeds the 

maximum firing rate at the Craig Generating Station. The 2011 NEI information for electric 

generating coal facilities in Colorado indicates that 745.8 lbs (0.37 tons) of mercury were 

emitted from coal facilities. The 62.24 lbs/yr described above from the 2013 TRI is 8.3 percent. 

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The more recent emission rate is representative into the future because of MATS compliance. 

The national mercury total is 25.6 tons; thus the Craig Generating Station would contribute 

0.12 percent which would be negligible.

Finally, a mercury deposition network (MDN) monitoring site is located adjacent to the air 

quality study area in Routt County just east of Steamboat Springs. This site has provided data 

to the MDN since 2007. The MDN site measures mercury deposition from all sources and 

does not have the ability to specify the particular source of mercury. Based on mapped 

mercury deposition products from the MDN, the regional air quality study area has seen little 

change in total average mercury wet deposition during the period from 2007 through 2013. 

Given that regional coal combustion is not likely to increase as a result of Alternative A, the 

total deposition would be likely to remain consistent with the mapped data from 2013. It 

should be noted, however, that deposition monitoring values for total wet deposition at the 

Routt Monitoring Station increased approximately 2μg/m2 from 7.8 μg/m2 in 2008 to 9.8 μg/m2 

in 2013 even in the face of declining regional mercury emissions. This is likely a result of 

refined monitoring methods and not a reflection of increasing mercury deposition. Mercury 

deposition has a global reach and can be transported far away from its originating location. Thus, 

global transport could be the cause of increasing overall mercury deposition even with declining regional 

emissions. Mercury deposition has a global reach and can be transported far away from its originating 

location. Thus, global transport could be the cause of increasing overall mercury deposition even with 

declining regional emissions (EPRI 2014).

4.3.1.5 Indirect Railroad Emission Estimates

Coal Transporting 

Coal transportation emissions were calculated for the indirect effect of coal movement via rail. 

The maximum emissions from railroad coal transportation are based on an annual shipping rate 

of 6 mtpy. The mass of coal per railcar is 100 tons, and a coal train is normally comprised of 

110 railcars. That equates to 11,000 tons of coal per rail shipment. The estimated maximum 

number of annual shipments is 545. An engine load was estimated from the force required to 

move the total train weight (4 engines per train and 4,000 brake horsepower (bhp)/engine). 

Each engine is Tier 4 compliant.

Locomotives also contribute to black carbon emissions similar to the haul trucks discussed in 

Section 4.3.1.2. Explicit PM10 black carbon emissions associated with rail operations are 

included in Table 4.3-12. 

The one-way haul distance is 28 miles (45 km) with an assumed maximum allowable speed of 

80 mph for freight trains. Emissions were calculated for the round trip assuming this distance 

each direction. This distance represents a conservative estimate of the length of the mine’s rail 

spur which is the only portion that can be accurately estimated. Based on that scenario, the 

maximum annual operating hours of the train is 382. Emissions are determined by the annual 

power usage, which is 6.1 million bhp-hours. Table 4.3-12 outlines the criteria pollutant 

emissions, HAP emissions, and GHG emissions associated with coal transportation by rail.

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Railroad Maintenance 

In addition to transport, railroad maintenance activities also produce indirect emissions. Each 

railroad maintenance action typically occurs once per year and runs for a duration of 

approximately four weeks. During the four week maintenance period each piece of equipment 

ranges in usage from six days to three weeks. All equipment is operated by diesel engines each 

of which are EPA Tier certified ranging from Tier 1 to Tier 4. Table 4.3-12 outlines the 

emissions that would be associated with a four week maintenance project under Alternative A.

Table 4.3-12 Railroad Coal Transportation and Railroad Maintenance Emission 

Estimates (tpy) 

Source PM10 PM2.5 NOx CO VOC SO2 HAPs GHG1 Black 

Carbon2

Coal 

Transportation 0.1 0.1 6.7 8.6 0.3 0.03 0.02 3,284 0.3

Railroad 

Maintenance 0.1 0.1 0.5 0.5 0.1 0.1 1.5E-02 605 0 

Total 0.2 0.2 7.2 9.1 0.4 0.1 0.04 3,889 0.3

1 Greenhouse gas emissions are presented as CO2e metric tonnes per year. 2 Black carbon is a component of particulate. Therefore, total PM10 and PM2.5 would equate to 0.5 and 0.4 tons/yr, 

respectively with black carbon included.

All criteria pollutants and HAP emissions associated with railroad activities were compared to 

the county data from the 2011 NEI. Alternative A would contribute a maximum of 0.0164 

percent of all criteria pollutants and 0.0405 percent of all HAPs emitted within Garfield, 

Moffatt, Rio Blanco, and Routt counties. The indirect emissions from railroad activities under 

Alternative A would be insignificant when compared to total HAPs emitted in the surrounding 

counties. 

4.3.2 Alternative B – PR02 as Revised

All air quality analyses from 2007 to 2014 assume actual throughput values associated with the 

mine. Ambient air quality analysis conducted for 2014 assumed a maximum annual coal 

throughput of 4 mtpy. Operations in 2014 are considered a maximum emissions scenario 

because subsequent years are expected to produce less coal through the life of the mine to 

2019. Eleven actual operational scenarios were simulated to demonstrate all foreseeable 

realistic equipment combinations.

4.3.2.1 Previous Impacts

Emission Estimates – Mining Activities (2007-2014) 

Colowyo is required to submit air emissions information to CDPHE a minimum of every five 

years through the submission of Air Pollution Emission Notices (APEN). The information 

submitted via APEN includes particulate emissions. Other emissions such as GHGs and HAPs, 

as well as emissions associated with transport of the coal via rail from the mine to the Craig 

Generating Station, were established using actual equipment data.

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APEN Particulate Data

APEN data was supplied to CDPHE in 2007, 2009, 2012, and 2013 for the timeframe of interest 

(2007-2014). All APEN data is compared to applicable permit limitations associated with the 

mine. Colowyo submits up to nine individual APEN forms during each submittal year. Table 

4.3-13 provides specific activities associated with each APEN. 

Table 4.3-13 APEN Activity Breakdown

APEN # CDPHE Category Activities

Blasting

Scrapers

Drilling

Shovels

Draglines

21 Fugitive Mining Loaders

Dozers

Graders

Haul trucks

Water trucks

Pit Erosion

Loading/unloading

Unloading Coal to hopper

22 Primary Crusher Primary Crushing

Convey to Storage Bins

Loading to belly dump trucks

Haul coal to crusher

Unloading coal

23 Secondary Crusher Secondary Crushing

Convey to stacking tube

Storage pile at tube

24 Rail Loading Railcar Loading

25 Storage pile/Reclaim Storage pile at 2nd crusher etc.

Aux coal loading/unloading

26 Auxiliary Coal System Aux coal crushing

Aux coal loading to truck

Aux coal loaded to truck to market

27 Coal Auxiliary Handling Unloading to railcar siding

Loading w/ FELs to railcars

28 Rock/Haul Road Rock hauling/loading to crusher

Maintenance Crushing/screening

Rock storage piles

29 Material Handling Hauling/storing rock from crusher

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Table 4.3-14 identifies the maximum annual particulate emissions from 2007 to 2014 that 

contributed to Colorado emissions. 

Table 4.3-14 Maximum APEN Particulate Estimates from 2007-2014

APEN Emission Source PM 

(T/yr)

PM10 

(T/yr)

PM2.5 

(T/yr)

21 Fugitive 5304 1334 392.4 

22 Primary 26.2 8.3 1.8

23 Secondary 8.3 6.8 1.8

23 Haul trucks 807 158 3.2

24 Railcar 0.1 3E-02 4E-03

25 storage/reclaim 13.3 6.7 2.0

26 Auxiliary coal sys 3.1 0.9 0.4

26 coal load/unload 2.2 0.4 0.1

27 load/unload/haul 1.2 0.6 0.1

28 crusher/screens 3.0 1.1 0.2

28 loaders/haul road 4.0 1.2 0.4

29 Haul/storage rock from crusher 0.8 0.3 5E-02

Total 6,173 1,518 402

The maximum particulate emissions associated with Alternative B were established in 2012 

primarily due to fugitive emissions. An aggregated total of 2012 APEN information shows that 

PM2.5 and PM10 emissions were 402.5 and 1,518.3 T/yr, respectively. Compared to the state and 

national NEI data, Alternative B contributed 0.4 percent and 0.46 percent of Colorado’s 

particulate emissions for PM2.5 and PM10. National contributions were 0.006 percent and 0.007 

percent, respectively. These percentages are insignificant by comparison to statewide and 

national totals.

County comparisons to the 2011 NEI data suggest that the maximum particulate emissions 

potential associated with Alternative B are 6.9 percent. This is considered moderate, but the 

region still maintained its attainment designation by the EPA and CDPHE. 

Onsite (North and Gossard) Particulate Monitoring Data

In addition to emissions data, the mine has collected ambient air quality concentration data for 

atmospheric particulates smaller than 10 microns. Data is collected at two sites, known as the 

Gossard and North sites (Section 3.3), using federal equivalent method (FEM) monitors. FEM 

monitors onsite are not used for attainment/nonattainment determination by CDPHE and the EPA. 

Therefore, the data obtained by these monitors is not directly used for NAAQS compliance purposes. 

The following discussion outlines the monitored high value events and their comparison to the standard. 

However, note that a high monitored value does not correlate to a NAAQS violation. 

The Gossard location particulate monitoring data is provided from July 2011 through 

December 2013. The North location particulate monitoring data was split into three, threeOSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 4-27

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year segments for evaluation against the NAAQS standard (Table 4.3-15) as the standard is 

based on a three year averaging period of concentrations.

Table 4.3-15 Monitoring Station Potential High Values, Alternative B

3-Year Total Daily Values 

Station Timeframe ≥ 154.4 μg/m3

Aug 2008-July 2011 8

North Aug 2009-July 2012 4

Aug 2010-July 2013 2

Gossard July 2011-Dec 2013 1

Between August 2010 and July 2013, 24-hr PM10 concentrations at the North monitor show high 

values two times; between July 2011 and December 2013; concentrations at the Gossard 

monitor are elevated once. However, the NAAQS standard allows for one exceedance per 

year on average over the three year period. Therefore, because the total number of 

exceedances was less than three for each of the above mentioned segments, those are not 

considered NAAQS violations. 

The August 2008 through July 2010 and August 2009 through July 2010 North monitoring 

segments have an overlapping time period of two years (August 2009 – July 2010). As a result, 

any exceedances that occurred between August 2009 and July 2010 are double counted. There 

were eight total high values between August 2008 and July 2011 (Table 4.3-16). The number 

of monitored high values therefore was greater than the allowed standard of no more than one 

exceedance per year averaged over three years.

Table 4.3-16 High Value Dates

Station Date of 

Exceedance

24 HR Average

(μg/m3) 

11/2/2008 299.00

3/4/2009 233.44

3/22/2009 170.84

7/6/2009 156.64

North 9/29/2009 283.76

9/30/2009 266.78

12/4/2009 184.76

5/28/2010 203.59

5/26/12 199.42

Gossard 5/26/12 199.42

During review of particulate emission sources at the mine site, two primary direct causes of 

these high values were discovered. On each of the days a high value occurred, operational 

activities occurred in close proximity to the R3 coal stockpile. The nine exceedances between 

August 2008 and July 2013 also coincided with climatic conditions conducive to excessive 

fugitive dust formation. 

The main contributors of particulates to the high values at the North monitor were likely the 

activities associated with the R3 coal stockpile. Scanning Electron Microscopy (SEM) analysis of 

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the North monitor filter resulted in approximately 25.2 percent of the particulate mass on the 

filter being comprised of carbon-based material, suggesting coal dust as the particulate source. 

This confirmed the assumption that dust from the R3 coal stockpile significantly contributed to 

the high values at the North monitor.

In order to prevent further air quality issues Colowyo developed a Dust Mitigation Plan 

(Colowyo 2010a), aimed at minimizing future particulate emissions. 

Since implementation of the Dust Mitigation Plan only one high value event has been recorded 

at the North monitor. In addition, many of the monitored high values associated with the mine 

can be attributed to an exceptional event. An exceptional event is determined by the EPA and 

can include natural phenomena such as high winds and wildfires, which may apply to the 

Colowyo Mine. On March 22, 2007, the EPA promulgated the current Exceptional Events Rule 

(EER, 40 CFR 50 and 51). According to this rule, exceptional events are unusual or naturally 

occurring events that can affect air quality, but are not reasonably controllable or preventable 

using approved mitigation techniques that state and local air quality agencies have implemented 

in order to attain and/or maintain the NAAQS. These events are flagged as exceptional events 

and are not used in the determination of NAAQS attainment status. 

Elevated PM10 Events at North Site

The eight exceedance events (Table 4.3-16) were addressed by Colowyo in a Mitigation 

Modeling Report issued in June 2010 (Colowyo 2010b). Although it was determined that the 

primary contributor to the eight high values that occurred between 2008 and 2010 were coal 

dust emissions from the R3 stockpile and fugitive dust from the maintenance/parking area, three 

of those events could possibly be considered exceptional events. 

High Concentration Days Evaluation

Table 4.3-17 illustrates a summary of the three 24-hr PM10 high value days which can 

potentially be identified as exceptional events. The table identifies the average and maximum 

wind speed on the days the exceedances occurred.

Table 4.3-17 High Wind Days

Station Date of 

Exceedance 

Average Wind 

Speed 

(meters/second 

[m/s])

Maximum Wind 

Speed (m/s)

11/2/2008 8.2 12.5

North 9/29/2009 7.3 9.2

9/30/2009 8.2 14.6

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The EPA guidance for exceptional events identifies a wind speed threshold of 11.2 m/s (25 

mph). The maximum wind speeds for November 2, 2008 and September 30, 2009 exceed the 

11.2 m/s threshold (Table 4.3-17). This occurred for two of the six hours when the NAAQS 

were exceeded during November 2, 2008 and three of the six hours during September 30, 

2009. The hours with highest wind speed correlate with the time when the highest 

concentrations were observed for November 2008. The correlation does not hold true for 

September 2009, but during the highest wind hours, the air quality monitor malfunctioned. Had 

that not occurred, it is likely that the concentrations would have been high. Additionally, all 

hours for which data was recorded showed a wind speed of greater than the 95th percentile of 

the EPA threshold for September 30, 2009 and for a third of the hours for November 2, 2008. 

Therefore, it is reasonable to conclude that for those two days of high values, an exceptional 

event had occurred.

The data suggest some variation for September 29, 2009. The maximum hourly wind speeds 

do not meet the 11.2 m/s threshold, nor do any exceed the 95th percentile. However, unlike 

the other two events that were evaluated, there was not a significant variance and standard 

deviation of the wind speeds. Both November 2, 2008 and September 30, 2009 were relatively 

calm days with only a handful of hours with very high winds, while September 29, 2009 had 

consistent winds for the entirety of the day.

With the mitigation now in place, the removal of stockpile R3, and chemical stabilization of the 

maintenance parking lot and boneyard, the direct emissions associated with Alternative B would 

be unlikely to produce any high values in the future unless there is a regional exceptional event.

Gaseous Criteria Pollutants

Unlike the particulate emissions, APEN data was not available from CDPHE for all gaseous 

pollutants. Therefore, all emission estimates are based on actual data supplied by the mine. 

NOx, CO, SO2, and VOC emissions from blasting, drilling, and tailpipe exhaust at the mine were 

evaluated. The equipment that contributes to tailpipe emissions consists of all haul trucks (50 

ton capacity, 170 ton capacity from 2007-2010, and 240 ton capacity), scrapers, graders, dozers, 

and water trucks. Emissions from the scrapers, graders and dozers occur in the South Taylor 

pit. Hauling either occurs within the pit or along the paved haul road leading to the rail loop. 

Direct Gaseous, GHGs, and HAPs Annual Emissions

Emissions for gaseous pollutants, GHGs, and HAPs were calculated for the mine activities that 

occurred from 2007 to 2014 (Table 4.3-18). The emissions calculations utilized activity rates 

that were provided by Colowyo for the mining that occurred annually during that period.

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Table 4.3-18 Maximum Emission Estimates 2007-2014 (tpy) 

Emission Unit SO2 CO NOx VOC HAP GHG1

Scrapers 1.68E-04 0.227 0.126 0.148 1.16E-02 481

Drilling 0.013 7.189 27.063 0.913 3.85E-02 1,515

Dozers 0.002 2.856 1.585 6.274 3.20E-01 16,808

Graders 0.001 1.662 0.922 0.331 1.17E-01 2,551

Haul Trucks (170T coal) 0.001 1.427 0.707 0.387 5.74E-02 1,644

Haul Trucks (240T OB/Coal) 0.006 7.607 4.221 2.005 2.97E-01 10,650

Water trucks 0.001 0.700 0.364 0.469 6.96E-02 249

Blasting 0.499 5,575 882 0.161 1.15E-03 36,919

Access Road 0.001 1.172 0.090 3.224 5.00E-02 4,110

Haul coal to Crusher (50T) 0.008 11.889 5.890 0.125 4.78E-01 45

Total 0.532 5,610 923 14.0 1.44 74,972

1

Greenhouse gas emissions are presented as CO2e metric tonnes per year.

For all gaseous pollutants (CO, NOx, SO2, and VOC) the maximum emission year was selected 

for comparison to state and national totals. VOC maximums were established in 2007; the 

other three pollutants in 2009. Previous contributions were in the range of 0.01 percent to 9.8 

percent of the surrounding counties gaseous emissions when compared to the 2011 NEI data. 

The maximum annual emissions ranged from 0.001 percent to 0.4 percent of the statewide 

total. Nationally, previous contributions ranged from 0.00001 percent to 0.01 percent. 

Previous gaseous emissions did not contribute significantly when compared to the statewide or 

national totals.

The operational year of 2007 contributed to the previous maximum HAP emissions. The 1.44 

tons comprised 1.7 percent of the surrounding county total and 0.001 percent of the statewide 

total of 195,455 tons (as reported to the EPA in the 2011 NEI database). Nationally, the 

contribution was 0.00002 percent. Again, previous contributions were insignificant when 

compared to state and national totals. 

Direct Methane Release Emissions

Under Alternative B, extraction of coal from the South Taylor pit began in 2008 and would 

cease in 2019. Methane release and post-mining emissions were estimated based on 

calculations described in Section 4.3.1.2. Table 4.3-19 outlines the methane gas release 

estimates, reported at CO2e, from coal and overburden for each year from 2008 through 2014 

as well as the total methane emissions from 2015 to the end of the mine life.

Table 4.3-19 Annual Methane Emissions 2015-2019, Alternative B

CO2e (metric tons/year)

GHG 2008 2009 2010 2011 2012 2013 2014 4 mtpy End of Mine1

CH4 722 802 858 1,123 762 919 1,117 2,444 7,499 1 The end of the mine represents 2015 through 2019 methane emissions based on an aggregated tonnage of 

extracted coal (remaining 13.0 million remaining tons).

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 4-31

Mining Plan Modification Environmental Assessment
Chapter 4 – Environmental Consequences

Direct Black Carbon Emissions

All haul truck types under Alternative B were evaluated for their contribution of black carbon 

as a percentage of overall particulate (Table 4.3-20).

Table 4.3-20 Black Carbon Emissions (tpy) from Haul Trucks, Alternative B

Haul Black Carbon PM2.5

Truck1 2007 2008 2009 2010 2011 2012 2013 2014

50 Ton 0.045 0.039 0.029 0.021 0.021 0.017 0.016 0.020

170 Ton 0.005 0.005 0.003 0.003 0.000 0.000 0.000 0.000

240 Ton2,3 0.016 0.014 0.010 0.007 0.016 0.013 0.026 0.016

Access Road4 3.79E-04 3.79E-04 3.79E-04 3.79E-04 3.79E-04 3.79E-04 3.79E-04 3.79E-04

Haul Black Carbon PM10

Truck1 2007 2008 2009 2010 2011 2012 2013 2014

50 Ton 0.053 0.046 0.034 0.025 0.025 0.020 0.018 0.023

170 Ton 0.006 0.006 0.004 0.003 0.000 0.000 0.000 0.000

240 Ton2,3 0.017 0.015 0.011 0.008 0.018 0.015 0.029 0.017

Access Road4 4.10E-04 4.10E-04 4.10E-04 4.10E-04 4.10E-04 4.10E-04 4.10E-04 4.10E-04 1 Based on the length of the road, a percentage of the total vehicle miles traveled (VMT) are allocated to the 

paved road and in-pit road, respectively, speed of 25 mph. 2 Is assumed to only be spoil material through 2010 until the 170T trucks were removed. Assumed speed of 25 

mph. 3 Starting in 2011 240T trucks hauled both spoil material and coal. A percentage of the total VMT are allocated 

to the paved and in-pit roads. 4 59/41% Ratio between cars and trucks; Model year 2000 cars/trucks assumed. 

4.3.2.2 Potential Impacts

Potential Emissions Impacts – Based on Maximum Mining Rate of 4 mtpy

An annual mining rate of 4 mtpy is representative of maximum foreseeable production through 

the completion of active mining under Alternative B. GHG emissions are derived from all 

mobile sources associated with Alternative B (Table 4.3-21). This includes in-pit, hauling, rail 

maintenance, and access road components. Criteria pollutants and HAP calculations (Table 

4.3-22) include all fugitive sources, process emissions, combustion activities and railroad 

maintenance under Alternative B.

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 4-32

Mining Plan Modification Environmental Assessment
Chapter 4 – Environmental Consequences

Table 4.3-21 Alternative B GHG Emissions, 4 mtpy

Activity CO2

(mtpy)

CH4

(mtpy)

N2O 

(mtpy)

CO2e

(mtpy)

Scrapers 2,504 0.14 0.07 2,528

Drills 1,315 0.05 0.01 1,320

Dozers 39,491 2.21 1.08 39,867

Graders 22,229 1.24 0.61 22,441

Haul Truck (240T) 18,927 4.74E-03 4.77E-03 18,928

Water Trucks 9,659 0.01 0.01 9,662

Blasting 56,071 1.98 0.53 56,278

Haul Coal to Crusher (50T) 7,927 0.01 0.01 7,930

Access Road 55 3.23E-03 0.01 57

Rail Maintenance 364 0.53 1.32 771

Total 158,542 6.18 3.64 159,782

Table 4.3-22 Alternative B Direct Criteria Emissions, 4 mtpy

Mining Rate PM10

(tpy)

PM2.5 

(tpy)

NOx

(tpy)

CO

(tpy)

VOC

(tpy)

SO2

(tpy)

HAPs

(tpy)

4 mtpy 1,528 179 1,257 7,461 48 0.9 6.1

Similar to Alternative A (6 mtpy) and actual emissions from 2007 to 2014, the direct emissions 

impact for a maximum mining rate into the future of 4 mtpy would be insignificant when 

compared to both state and national criteria, GHG, and HAP totals. HAPs associated with a 4 

mtpy scenario would contribute 7.1 percent, 0.003 percent, and 0.00007 percent of 

surrounding counties, Colorado and national totals, respectively. Gaseous pollutants would 

range from 0.01 percent to 13.0 percent of county totals, 0.00001 percent to 0.01 percent of 

the national totals and 0.002 percent to 0.53 percent statewide. The 4 mtpy would contribute 

0.12 percent of statewide GHGs and 0.007 percent nationwide. 

Dispersion Modeling Impact Analysis

The 2014 operating year was modeled to ensure NAAQS compliance for the remaining years 

of active mining within the Project Area. Eleven scenarios of equipment allocation were 

analyzed and modeled, each as hypothetical real-life situations that could occur on any given 

day. Daily and annual activity rates were derived from the number of trucks, dozers, scrapers, 

etc. that the mine currently has onsite, initially based on a 4 mtpy mine plan. The following 

section describes the methodology used in preparing model inputs and assumptions made 

within the model itself. 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 4-33

Mining Plan Modification Environmental Assessment
Chapter 4 – Environmental Consequences

Modeling Inputs

AERMOD utilizes several input parameters to simulate emissions and their corresponding 

dispersion characteristics. Colowyo collects meteorological data from an onsite meteorological 

station located at the following NAD 83 coordinates: 40°16’22.8’’ N, 107°48’36’’ W, elevation 

7395 ft. These data were used as input following validation by CDPHE modeling personnel. 

Data beginning in July 2008 to June 2011 and July 2012 to June 2013 were accepted by CDPHE 

and used in the analysis. A windrose of the data collected from July 1, 2008 through June 31, 

2013 is presented as Figure 4-1. A year-to-year data comparison showed consistency in the 

average wind speeds and directions and indicated that meteorological data was consistently 

collected. Wind directions had a strong tendency toward west/southwest directionality. 

Speeds varied somewhat; however, they tended to be strongest from the southwest and west.

Two beta options are available in AERMOD to address concerns regarding model performance 

under low wind speed conditions. One of these options, the low wind speed option 2 

(LOWWIND2), was employed for the modeling analyses. This option has been shown to 

enhance model accuracy during periods of low wind speeds and was selected to ensure the 

most accurate model outputs. The LOWWIND2 option increases the minimum value of 

sigma-v from 0.2 to 0.3 m/s, and incorporates the meander component, with some adjustments 

to the algorithm, including an upper limit on the meander factor (FRAN) of 0.95. Default values 

of sigma-v of 0.3 m/s and upper limit meander factor of 0.95 were utilized in the analyses.

Modeled Pollutants and Assumptions

Dispersion modeling was conducted to estimate the potential future air quality impacts from 

the following criteria air pollutants for the indicated regulatory time periods. All modeled 

concentrations are applicable at any point of public access.

• PM10 – 24 hour

• PM2.5 – 24 hour and Annual 

• NO2 – 1 hour and Annual

• SO2 – 1 hour 

• CO – 1 hour and 8 hour 

Compliance with the NAAQS was demonstrated by averaging the hourly and the annual 

modeled values for each pollutant, as specified in 40 CFR Part 51 Appendix W. The EPA is

currently proposing an update to the guidance outlined in Appendix W. The pollutants were 

modeled without background concentrations. The modeled concentrations for each pollutant 

were added to background concentrations for comparison to the NAAQS. Modeling was not 

performed for lead because the lead emissions from the Project are expected to be negligible.

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 4-34

Mining Plan Modification Environmental Assessment
Disclaimer: Figure prepared for OSMRE by Stantec. Stantec assumes no responsibility for data 

supplied in electronic format. The recipient accepts full responsibility for verifying the accuracy and 

completeness of the data. The recipient releases Stantec, its officers, employees, consultants and 

agents, from any and all claims arising in any way from the content or provision of the data.

Figure No.

Title

Project Location

Project

4-1

Modeled Period Windrose

Rio Blanco & Moffat Counties 

Colorado

Colowyo Coal Mine, South Taylor/Lower Wilson 

Permit Expansion Area Mining Plan Modification 

Environmental Assessment

Data Period: 

Start Date: 7/1/2008 - 00:00

End Date: 6/30/2013 23:00

Calm Winds: 

0.54%

Average Wind Speed:

4.54 meters/second

Total Count:

34763 hours

Date:

2/2/2015

South

West East

North

15%

12%

9%

6%

3%
Chapter 4 – Environmental Consequences 

Background Concentrations

To evaluate the potential impacts of emissions from the Project, the dispersion modeling 

evaluation considered the existing background concentrations of pollutants in the area where 

impacts are being evaluated. The background concentration of a given pollutant is added to the 

modeled impact, and the result is compared to the EPA's NAAQs. The NAAQS are allowable 

concentration limits applied at the public access boundary. 

The CDPHE (Nancy Chick, CDPHE via letter) provided background concentrations that could 

be used for permitting at the mine. These background values were selected for use in this 

analysis (Table 4.3-23).

Table 4.3-23 Background Concentration Values

Pollutant Averaging 

Period

Background 

Concentration 

(μg/m3)

PM2.5 24-hr 14

Annual 3

PM10 24-hr 23

SO2 1-hr 3

NO2 1-hr 20

Annual 2 

CO 1-hr 1,145

8-hr 1,145

Source Types

The Colowyo Mine consists of several types of emission sources. In general these include: 

point sources, surface area sources, volume sources (comprise all road sources, blasting, and 

railcar emissions), open pit sources (in-pit mining activities) and tailpipe emissions. Figure 4-2 

provides a general geographic representation of all modeled sources within the Project Area 

and relative distance to the outermost level of receptors (purple square on inset). Model 

receptors were placed throughout the region from the orange boundary to the purple square. 

Additionally, receptors were placed along County Road 51 within the Project Area. 

Modeled Operating Scenarios

South Taylor coal extraction is maximized during 2014 operations at 4 mtpy. Mining 

operations are expected to continue through 2019. All subsequent years (2015-2019) are 

expected to have less than 4 mtpy of coal extracted. Therefore, all modeled 2014 operating 

scenarios represent the worst case potential emissions related to direct mining activities for the 

duration of the Project. 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 4-36

Mining Plan Modification Environmental Assessment
Chapter 4 – Environmental Consequences 

In order to account for operational uncertainty, multiple operational scenarios were modeled 

for 2014. These scenarios correspond with differing proposed onsite activities in various 

geographic regions, such as reclamation activities in one area versus another or differing 

equipment utilization. Each operations scenario was developed cooperatively with Colowyo 

staff and is based on fleet limitation and operational goals. Eleven operational scenarios were 

applied.

The dispersion modeling of all scenarios indicates that the emissions under Alternative B would 

not exceed the NAAQS for the pollutants modeled. This suggests that Alternative B at the 

proposed future maximum mining rate would not cause a significant impact to the NAAQS. 

Table 4.3-24 illustrates that all potential operational scenarios would be compliant with all 

NAAQS when implementing the maximum foreseeable mining rate of 4 mtpy. The 24-hr PM2.5

is the closet standard to being exceeded at 94.6 percent.

Table 4.3-24 Minimum & Maximum Impacts 2014 Ambient Analysis

Pollutant Averaging 

Period

Background 

Concentration 

(μg/m3) 

Minimum 

Model 

Results

(μg/m3)

Maximum 

Model 

Results

(μg/m3)

Total

Range

(μg/m3)6

NAAQS 

(μg/m3) 

Percent of 

Standard

Range

PM2.5

1 24-hr 14 13 19 27-33 35 78.2-94.6%

Annual 3 4 7 7-10 12 57.6-80.7%

PM10

2 24-hr 23 48 103 71-126 150 47.3-83.8%

SO2

3 1-hr 3 0.98 1.13 4 196 2.03-2.22%

NO2

1,5 1-hr 20 147.94 147.96 168 188 89.3-89.4%

Annual 2 5.8 6.0 7.8-8.0 100 7.8-8.0%

CO4 1-hr 1,145 16,475 18,358 17,620-

19,503

40,000 44.1-48.8%

8-hr 1,145 3,812 4,297 4,957-

5,442

10,000 49.6-54.4%

1 8th high value

2 5th high over 4 years, deposition applied 

3 4th high value

4 2nd high value, standard not to be exceeded more than once per year 5 Use of OLM

6 Total Range represents the summation of background concentrations and modeling results

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 4-37

Mining Plan Modification Environmental Assessment
Colorado

#*#*#*#*#*#*#*#*#*

#*#*#*#*#*#*#*

West

Pit

East

Pit

Spoil

Pile

West Pit

Reclaim

South

Taylor

Pit

4N 94W

4N 93W

4N 93W

3N 93W

3N 94W

3N 93W

Geographic Location of

Modeled Sources

4-2

Colowyo Coal Mine, South Taylor/Lower Wilson

Permit Expansion Area Mining Plan Modification

Environmental Assessment

($$ ̄

0 3,200 6,400

Feet

1:38,400 (At Original document size of 11x17)

Sources

#* Blasting

Access Road

Haul Road

Rail Loop

Polygon Sources

Project Area

Approved SMCRA Permit Area

Receptor Boundary

Township Boundary

Project 

Location

Notes

1: Coordinate System: NAD 1983 UTM Zone 13N

2: Service Layer Credits: Content may not reflect National

Geographic's current map policy. Sources: National

Geographic, Esri, DeLorme, HERE, UNEP-WCMC, USGS, NASA,

ESA, METI, NRCAN, GEBCO, NOAA, increment P Corp.

Disclaimer: Figure prepared for OSMRE by Stantec. Stantec assumes no

responsibility for data supplied in electronic format. The recipient

accepts full responsibility for verifying the accuracy and completeness

of the data. The recipient releases Stantec, its officers, employees,

consultants and agents, from any and all claims arising in any way from

the content or provision of the data.

Figure No.

Title

Area of Map

Extent

Rio Blanco & Moffat Counties

Colorado

Project Location

Project
Chapter 4 – Environmental Consequences

4.3.2.3 Indirect Combustion Criteria Impacts

As described for Alternative A, emissions for criteria pollutants have been calculated for the 

combustion of mined coal. For Alternative B, emissions were calculated for the actual coal 

mining rate (assuming all coal mined was combusted) from 2007 through 2014 (the previous 

impacts) as well as the maximum proposed future mining rate and the current coal contract 

rate for the Craig Generating Station (potential impacts). As with Alternative A, the emissions 

were calculated using the regional maximum emission factor, the average regional emissions 

factor, and the Craig Generating Station emission factor. The resultant emissions are 

presented in Table 4.3-25. 

Table 4.3-25 Predicted Criteria Emissions, Alternative B

Emissions 

Method

Coal 

Combustion 

Rate (tpy) 

PM10

(tpy) 

PM2.5 

(tpy) 

CO 

(tpy) 

NO2

(tpy) 

SO2

(tpy) 

VOC

(tpy) 

Regional Maximum

2007 37,478 3.17 1.44 11.35 138.65 49.84 1.05

2008 1,181,227 99.93 45.51 357.75 4369.87 1570.86 33.16

2009 1,313,287 111.10 50.59 397.74 4858.41 1746.48 36.87

2010 1,404,226 118.79 54.10 425.29 5194.84 1867.42 39.42

2011 1,837,196 155.42 70.78 556.41 6796.57 2443.21 51.57

2012 1,247,203 105.51 48.05 377.73 4613.94 1658.60 35.01

2013 1,503,249 127.17 57.91 455.28 5561.16 1999.11 42.20

2014 1,828,253 154.67 70.43 553.71 6763.49 2431.31 51.32

Maximum Mining 4,000,000 338.39 154.10 1211.44 14797.71 5319.43 112.29

Contract Rate 2,300,000 194.57 88.61 696.58 8508.69 3058.67 64.57

Regional Average

2007 37,478 2.38 1.28 9.79 124.99 39.93 0.81

2008 1,181,227 74.95 40.32 308.65 3939.28 1258.59 25.60

2009 1,313,287 83.33 44.83 343.16 4379.69 1399.30 28.47

2010 1,404,226 89.10 47.93 366.92 4682.96 1496.19 30.44

2011 1,837,196 116.57 62.71 480.05 6126.88 1957.52 39.82

2012 1,247,203 79.14 42.57 325.89 4159.31 1328.88 27.03

2013 1,503,249 95.39 51.31 392.79 5013.19 1601.70 32.58

2014 1,828,253 116.01 62.41 477.72 6097.05 1947.99 39.63

Maximum Mining 4,000,000 253.81 136.54 1045.18 13339.63 4261.97 86.70

Contract Rate 2,300,000 145.94 78.51 600.98 7670.28 2450.63 49.85

Craig Only

2007 37,478 1.59 1.11 11.35 111.32 30.02 0.57

2008 1,181,227 49.98 35.13 357.75 3508.70 946.31 18.05

2009 1,313,287 55.56 39.06 397.74 3900.97 1052.11 20.06

2010 1,404,226 59.41 41.77 425.29 4171.09 1124.96 21.45

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 4-39

Mining Plan Modification Environmental Assessment
Chapter 4 – Environmental Consequences

Emissions 

Method

Coal 

Combustion 

Rate (tpy) 

PM10

(tpy) 

PM2.5 

(tpy) 

CO 

(tpy) 

NO2

(tpy) 

SO2

(tpy) 

VOC

(tpy) 

2011 1,837,196 77.73 54.65 556.41 5457.18 1471.83 28.07

2012 1,247,203 52.77 37.10 377.73 3704.67 999.17 19.05

2013 1,503,249 63.60 44.71 455.28 4465.23 1204.29 22.97

2014 1,828,253 77.35 54.38 553.71 5430.61 1464.66 27.93

Maximum Mining 4,000,000 169.23 118.98 1211.44 11881.54 3204.51 61.11

Contract Rate 2,300,000 97.31 68.41 696.58 6831.88 1842.59 35.14

The Hayden Generating Station emission rates would produce the highest PM10, PM2.5, SO2, 

VOC, and NOx emission rates of the two facilities while the Craig Generating Station would 

have the highest emission rate for CO. 

Emissions at the maximum Alternative B annual mining rate would range from 0.01 percent to 

5.75 percent of the total Colorado NEI emissions based on the Craig Generation Station only 

emission rate and would range from 0.02 percent to 9.55 percent of the total Colorado NEI 

emissions based on regional maximum emissions factor calculations (Table 4.3-26). It should 

be noted that these calculations over predict the amount of emissions that would reasonably occur as 

they would exceed the annual contracted coal delivery rate of 2.3 mtpy.

Emissions based on the actual mining rate from 2007 through 2014 ranged from 0.0 percent to 

2.64 percent of the Colorado NEI total based on the Craig Generating Station only emission 

rates and ranged from 0.0 percent to 4.38 percent of the Colorado NEI total based on the 

regional maximum emissions calculations (Table 4.3-26). 

As compared to the national NEI emissions totals, the 2007 to 2014 emissions rates 

represented between 0.00001 percent and 0.044 percent based on the worst case regional 

emission and between 0.00001 percent and 0.035 percent based on the Craig Generating 

Station emissions. For the maximum mining rate these percentages would rise to between 

0.00029 percent and 0.014 percent for the regional maximum emissions and between 0.00019 

and 0.095 percent for the Craig emissions factors. 

Emissions at the 4 mtpy mining rate when compared to the four surrounding counties would 

range from 0.1 percent to 78.8 percent. There would be significant contributions associated 

with the two generating stations, but the regional designation regarding NAAQS compliance

would not change and would remain in attainment. As described in Section 4.3.2.4, the state 

monitoring network has shown compliance with the NAAQS when natural exceptional events 

are excluded.

In general the maximum mining rate emissions impacts for Alternative B would be

approximately 30 percent lower than those for Alternative A. The emissions impacts would 

represent insignificant impacts relative to the national emissions totals and moderate emissions 

impacts relative to the Colorado emissions total. However, these emissions impacts would not 

be greater than the current emissions from the Craig Generating Station.

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 4-40

Mining Plan Modification Environmental Assessment
Chapter 4 – Environmental Consequences

Table 4.3-26 Predicted Criteria Emissions Compared to NEI, Alternative B

Emissions 

Method

Coal 

Combustion 

Rate (tpy) 

PM10 (% 

of CO 

State 

2011 

NEI)

PM2.5 (% 

of CO 

State 

2011 

NEI)

CO (% of 

2011 CO 

State 

NEI)

NO2 (% 

of CO 

State 

2011 

NEI)

SO2 (% 

of CO 

State 

2011 

NEI)

VOC (% 

of CO 

State 

2011 

NEI)

Regional Maximum

2007 37,478 0.00 0.00 0.00 0.05 0.09 0.00

2008 1,181,227 0.03 0.04 0.03 1.44 2.82 0.01

2009 1,313,287 0.03 0.05 0.03 1.60 3.13 0.01

2010 1,404,226 0.04 0.05 0.03 1.71 3.35 0.01

2011 1,837,196 0.05 0.07 0.04 2.23 4.38 0.01

2012 1,247,203 0.03 0.05 0.03 1.52 2.98 0.01

2013 1,503,249 0.04 0.06 0.03 1.83 3.59 0.01

2014 1,828,253 0.05 0.07 0.04 2.22 4.36 0.01

Max Mining 4,000,000 0.10 0.15 0.09 4.86 9.55 0.02

Contract 

Rate 2,300,000 0.06 0.09 0.05 2.80 5.49 0.01

Regional Average

2007 37,478 0.00 0.00 0.04 0.07 0.00 0.00 

2008 1,181,227 0.02 0.04 0.02 1.30 2.26 0.00

2009 1,313,287 0.03 0.04 0.02 1.44 2.51 0.01

2010 1,404,226 0.03 0.05 0.03 1.54 2.69 0.01

2011 1,837,196 0.04 0.06 0.03 2.01 3.51 0.01

2012 1,247,203 0.02 0.04 0.02 1.37 2.39 0.00

2013 1,503,249 0.03 0.05 0.03 1.65 2.87 0.01

2014 1,828,253 0.04 0.06 0.03 2.00 3.50 0.01

Maximum

Mining 4,000,000 0.08 0.13 0.07 4.39 7.65 0.02

Contract Rate 2,300,000 0.04 0.08 0.04 2.52 4.40 0.01

Craig Only

2007 37,478 0.00 0.00 0.04 0.05 0.00 0.00 

2008 1,181,227 0.02 0.03 0.03 1.15 1.70 0.00

2009 1,313,287 0.02 0.04 0.03 1.28 1.89 0.00

2010 1,404,226 0.02 0.04 0.03 1.37 2.02 0.00

2011 1,837,196 0.02 0.05 0.04 1.79 2.64 0.01

2012 1,247,203 0.02 0.04 0.03 1.22 1.79 0.00

2013 1,503,249 0.02 0.04 0.03 1.47 2.16 0.00

2014 1,828,253 0.02 0.05 0.04 1.79 2.63 0.01

Maximum

Mining 4,000,000 0.05 0.12 0.09 3.91 5.75 0.01

Contract Rate 2,300,000 0.03 0.07 0.05 2.25 3.31 0.01

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 4-41

Mining Plan Modification Environmental Assessment
Chapter 4 – Environmental Consequences

Indirect Coal Combustion GHG and Climate Change Impacts

Similar to Alternative A, GHG emissions were calculated for the coal combustion associated 

with Alternative B (Table 4.3-27). 

Table 4.3-27 GHG Coal Combustion Emissions, Alternative B

Coal Combusted (Short 

Tons) 

CO2

Emissions 

(metric 

tonnes)

CH4

Emissions 

(metric 

tonnes)

Total 

CH4 in 

CO2e 

(metric 

tonnes)

N2O 

Emissions 

(metric 

tonnes)

Total 

N2O in 

CO2e 

(metric 

tonnes)

Total 

CO2e 

(metric 

tonnes)

37,478 2007 Actual ST 

Mine Rate 87,154 10 257 1 445 87,856 

1,181,227 2008 Actual ST 

Mine Rate 2,746,908 324 8,098 47 14,041 2,769,047 

1,313,287 2009 Actual ST 

Mine Rate 3,054,010 360 9,004 52 15,611 3,078,624 

1,404,226 2010 Actual ST 

Mine Rate 3,265,487 385 9,627 56 16,692 3,291,805 

1,837,195 2011 Actual ST 

Mine Rate 4,272,344 504 12,595 73 21,838 4,306,778 

1,247,203 2012 Actual ST 

Mine Rate 2,900,334 342 8,551 50 14,825 2,923,710 

1,503,248 2013 Actual ST 

Mine Rate 3,495,760 412 10,306 60 17,869 3,523,935 

1,828,253 2014 Actual ST 

Mine Rate 4,251,548 501 12,534 73 21,732 4,285,814 

2,300,000

Current Craig 

Contract Annual 

Maximum

5,348,582 631 15,768 92 27,339 5,391,689 

4,000,000 Proposed Mine 

Rate Maximum 9,301,882 1,097 27,423 160 47,546 9,376,851 

23,314,641 Proposed Total 

Mine Tonnage 54,217,508 6,394 159,839 930 277,132 54,654,479

The values detailed in the table represent the calculated GHG emissions that occurred for the 

actual coal mining rates from 2007 to 2014. Emissions data has also been calculated for the 

combustion at the proposed annual maximum mining rate, the current mining rate for the Craig 

Generating Station, and total GHG emissions from the combustion of all coal to be mined 

under Alternative B through 2019. During the period from 2007 to 2014, actual coal mined in 

the Project Area generated emissions that annually accounted for between 0.0003 percent and 

0.015 percent of estimated global emissions and between 0.001 percent and 0.071 percent of 

estimated U.S. net emissions (previous impact). 

The future GHG emissions (potential impact) under Alternative B would account for between 

0.019 percent and 0.032 percent of estimated annual global emissions and between 0.089 

percent and 0.15 percent of estimated annual U.S. net emissions. Both the previous and 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 4-42

Mining Plan Modification Environmental Assessment
Chapter 4 – Environmental Consequences

potential impacts under Alternative B would be negligible and are less than those under 

Alternative A. 

Social Cost of Carbon

Due to the reduction in maximum future mining rate from 6 mtpy (Alternative A) to 4 mtpy 

(Alternative B), annual CO2 equivalent emissions would be reduced from 14,065,277 to 

9,376,851 mtpy (assuming all mined coal is burned in one year). As previously noted, specific 

threshold levels for the determination of significance or benefit can vary depending on 

numerous project factors. NEPA does not require a cost-benefit analysis. Presenting the SCC 

cost estimates quantitatively, without a complete monetary cost-benefit analysis that includes 

the social benefits of energy production, would be misleading. For this reason the SCC 

protocol was not applied for this assessment. GHG coal combustion emissions are quantified 

and contextualized against global and national GHG emissions above. 

Ozone Precursor Emissions Impacts

Based on maximum onsite blasting and the combustion at the Craig Generating Station at either 

the Alternative B maximum rate as well as at the reasonably foreseeable contracted rate, 

conservative estimates of O3 precursors are included in Table 4.3-28. The emissions were 

calculated in a fashion consistent with the method described for Alternative A.

Table 4.3-28 Predicted Ozone Precursor Emissions Rates, Alternative B

Emissions Method Coal Combustion 

Rate (tpy) NOX (tpy) VOC (tpy) 

Craig Generating Station Only 4,000,000 11,882 61.11

Craig Generating Station Only 2,300,000 6,832 35.14

Onsite Blasting Not applicable 882 0.16

Although these values represent large amounts of O3 precursors, emissions from the Craig 

Generating Station, as well as all other regional sources of precursor emissions, have not 

produced significant O3 impacts as indicated by regional O3 monitoring and the region’s 

attainment with the O3 NAAQS. A detailed description of the monitoring data for all criteria 

pollutants from 2007 through present is described in the following sections. The O3

component of these descriptions demonstrates that O3 impacts would not exceed the NAAQS 

and would therefore not be considered significant.

Indirect Mercury Emissions

During the period from 2007 to present, the Craig Generating Station has provided actual 

mercury emissions from all onsite atmospheric emission sources via the USEPA’s TRI program. 

Mercury emission for the Craig Generating Station from 2007 to 2013 was reported by the 

facility for all atmospheric emissions sources (Table 4.3-29).

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Table 4.3-29 TRI Reported Atmospheric Mercury Emissions for the Craig 

Generating Station

Reporting Year Hg Emissions Units

2007 TRI 130 lb/year

2008 TRI 130 lb/year

2009 TRI 30 lb/year

2010 TRI 43 lb/year

2011 TRI 43 lb/year

2012 TRI 44 lb/year

2013 TRI 42.4 lb/year

Based on the reported TRI emissions and the coal consumed at the Craig Generating Station 

reported during that period, an emissions factor can be calculated for a pound of mercury per 

ton of coal combusted. Based on the calculated emissions factors derived from the TRI, 

mercury emission impacts can vary significantly between the 2007 emissions controls in place at 

the Craig Generating Station and the 2013 emissions controls in place. The resultant mercury 

emissions impacts are detailed in Table 4.3-30. 

Table 4.3-30 Potential Coal Combustion Mercury Emissions Using Craig 

Generating Station TRI Actual Emissions

Coal 

Production

Emission Factor 

(Derived from 

2007 TRI)

Emission Factor 

(Derived from 

2013 TRI)

Total Predicted 

Hg Emissions

(Derived from 

2007 TRI)

Total Predicted 

Hg Emissions

(Derived from 

2013 TRI)

23.3 mt (Project 

Total)

2.58292E-05 (lb/ton 

combusted)

9.20858E-06 (lbs/ton 

combusted)

602.20

(lbs Hg)

214.70

(lbs Hg)

4 mtpy (Maximum 

Annual 

Production)

2.58292E-05 (lbs/ton 

combusted)

9.20858E-06 (lbs/ton 

combusted)

103.32

(lbs Hg/year) 36 (lbs Hg/year)

Using annual mine rates and the annual emission rates calculated from the TRI mercury 

emissions data, the contribution of emissions from Alternative B were calculated (Table

4.3-31).

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Table 4.3-31 Approximate Mercury Emissions from the Craig Generating Station 

Based on TRI Actual Emissions, Alternative B

Combustion Year Emissions Units

2007 1.0 lbs Hg/Year

2008 30.5 lbs Hg/Year

2009 8.4 lbs Hg/Year

2010 12.3 lbs Hg/Year

2011 17.1 lbs Hg/Year

2012 11.8 lbs Hg/Year

2013 15.5 lbs Hg/Year

Total 96.8 lbs Hg

As can be seen by comparing Table 4.3-29 and Table 4.3-31, mercury emissions from 2007 

to 2013 were significantly below those that would occur at the maximum mining rate. 

If all mercury emissions from the combustion of coal are calculated using the Craig Generating 

Station 2013 TRI emissions factor, the total mercury emissions that would be generated by 

burning the 23.3 million tons of coal mined under Alternative B would result in 214.69 lbs of 

mercury. This value is approximately 40 percent lower mercury emissions than those 

estimated by the same calculation for the coal mined under Alternative A.

Additionally, based on data available from the TRI data explorer, the electrical generation 

sector in Colorado generated approximately 1,070 lbs of mercury emissions for reporting year 

2013. The contribution of Alternative B coal combustion emissions was approximately 1.5 

percent of that total for 2013 based on actual mining rates and would only be 3.4 percent of 

the total mercury generated in Colorado under the Alternative B maximum mining rate 

(4 mtpy) if all of the coal was sent to the Craig Generating Station. When compared to the 

national mercury total of 25.6 tons, as reported in the 2011 NEI would be 0.09 percent. This 

represents a negligible to minor percentage of the total mercury generated both in Colorado 

and nationally.

4.3.2.4 Regional NAAQS Compliance

The following section outlines regional monitoring data from 2007 through 2013 associated with 

CDPHE. Unlike the onsite Colowyo monitors, those associated with CDPHE are federal reference 

method (FRM) monitors rather than FEM. The EPA has defined FRMs for the measurement of various 

criteria pollutants, such as carbon CO, O3, NO2, PM10, and PM2.5. These methods are described in 

detail in 40 CFR §50.1. For both PM10 and PM2.5, the FRM is based upon manual sampling techniques 

where a pre-weighed filter is installed into a sampling device, ambient air is sampled for 24 hours, and 

then the filter is retrieved, equilibrated and reweighed in order to determine the concentration of 

particulate on the filter. Only the measurement techniques defined in 40CFR §50.1 can be FRMs. The 

EPA also allows the use of FEMs for air quality surveillance. 

One requirement for FEM monitors is that they meet all EPA data quality objectives (DQO). DQOs are 

developed by the EPA to support primary objectives for each criteria pollutant and are statements that 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 4-45

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Chapter 4 – Environmental Consequences

define the appropriate type of data that should be collected. They also specify the tolerable levels of 

potential errors that are used as a basis for establishing the quality and quantity of data. FEM monitors 

must also meet appropriate EPA requirements regarding measurement standards. Each pollutant has a 

specific uncertainty measurement. For example, O3 requires an upper 90 percent confidence limit for 

the coefficient of variation (CV) of 15 percent and a bias of 95 percent confidence limit for the absolute 

bias of 15 percent. 

Both the North monitor and Gossard monitor are FEM monitors but are not operated as FEM monitors 

due to the fact that they do not meet all EPA-defined DQO. As a result, the data from the monitors 

may not be used for attainment/nonattainment area determination, and as such, the data from the 

North and Gossard monitors submitted to CDPHE is not included in the EPA’s national database of 

ambient air quality monitoring data. 

The monitored data discussed below are FRMs operated by CDPHE geared toward evaluating NAAQS 

compliance. Particulate matter, CO, and O3 data is shown and discussed in a regional NAAQS 

compliance context. 

Regional NAAQS Compliance

The regional monitoring network utilized by CDPHE is described in Section 4.3.1.4 under 

Regional O3 NAAQS compliance. While the network is consistent between Alternatives A and B, 

analysis for Alternative B examines the progression from year to year beginning in 2007 and 

ending in 2013.

2007 Compliance

Grand Junction is the only large city in the area and the only location that monitors for CO on 

the Western Slope. The other Western Slope monitors are located in the cities of Parachute, 

Rifle, Silt, Glenwood Springs, Delta, Durango, and Telluride. 

Table 37 of the CDPHE 2007 Air Quality Annual Report7 identifies the particulate annual 

average and 24-hr maximum concentrations at each monitor. The PM2.5 standards are 15 μg/m3

(annual) and 35 μg/m3 (24-hr), and the PM10 standard is 150 μg/m3. The PM2.5 annual standard 

was lowered to 12 μg/m3 on December 5, 2012. There are two 24-hr PM10 maximums that 

exceed the standard (New Castle 286 μg/m3 and the Grand Junction continuous monitor at 181 

μg/m3). The New Castle event was considered exceptional by CDPHE as it was associated with 

a nearby mud slide cleanup effort. Also, the Grand Junction result occurred with less than 75 

percent usable data for at least one quarter during the year. Table 38 of the annual report 

identifies the 1-hr and 8-hr CO maximums (2.9 ppm and 1.8 ppm, respectively) in Grand 

Junction. Both highs are well below the respective standards of 35 ppm and 9 ppm. 

2008 Compliance

Three O3 monitors were added to the Western Counties Monitoring Network in 2008 in Rifle, 

the Palisade Water Treatment facility, and in Cortez. 

7 CDPHE AQCD - 2007 Air Quality Data Report

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The maximum PM10 concentration was captured by the Parachute monitoring station at 210 

μg/m3

. However, one exceedance does not indicate a NAAQS violation. As discussed in 

Section 4.3.2.1, the PM10 standard is based on a three year average. In addition, Figure 37 of 

the 2008 Air Quality Annual Report indicated that the high concentrations seen at the 

Parachute site were due to construction in the vicinity of the monitor.

CO maximum was found to be less than the standard at 7.1 ppm and 2.6 ppm for 1-hr and 8-hr, 

respectively. It should be noted that the standard allows for the 2nd high value rather than the 

maximum for NAAQS compliance purposes.

O3 standards are based on the 4th high value averaged over a three year period for the 8-hr 

averaging period (standard of 0.075 ppm). The 4th high value maximum between the three new 

monitors in 2008 was 0.070 ppm at the Palisade Water Treatment facility. While it is close to 

the standard, the concentration is not representative of a three year average value, and the 

monitor was installed on May 30, 2008. It does not represent a complete year of data. 

2009 Compliance

The Monitoring Network remained unchanged for the region from 2008. Starting in 2009, 

CDPHE annual reports provided the calculated three year average number of exceedances for 

PM10 and the 98th percentile three year average for PM2.5. If the three-year average number of 

exceedances is greater than 1 and the 98th percentile average is greater than the standard 

(35μg/m3) that equates to a violation provided exceptional events are excluded. Table 4.3-32

illustrates that neither is exceeded; indicating that the region maintained its attainment status 

for 2009.

CO monitored maximums did not exceed 2.3 ppm and 2.2 ppm. Both Palisade and Cortez 

showed a maximum O3 4th high of 0.064 ppm.

2010 Compliance

The Monitoring Network remained unchanged for the region from 2009. The CDPHE as a 

whole saw 19 exceedances in 2010 on six separate days. Four of the towns within the 

Western Counties (Durango, Grand Junction, Clifton, and Telluride) were greatly impacted by 

large regional dust storms. In addition, several other high concentration days were 

documented as exceptional event by CDPHE8,9

 (Table 4.3-33).

8 CDPHE AQCD - 2007 Air Quality Data Report 9 CDPHE AQCD Division Exceptional Event Repository 

http://www.colorado.gov/airquality/tech_doc_repository.aspx#exceptional_events

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Chapter 4 – Environmental Consequences

Table 4.3-32 2009 Western Counties Particulate Monitor Concentrations

PM10 (μg/m3) PM2.5 (μg/m3)

Site Name Location Annual 

Avg.

24-

hr 

Max

3-yr Avg 

Exceedances1

Annual

Avg.

3-yr 

Weighted 

Avg.

24-

hr

Max

3-yr 

Avg

98th

%ile1

Delta County

Delta 560 Dodge St. 26.8 186 0.33 -- -- -- --

Garfield County

Parachute 100 E. 2nd Ave 25.3 83 0.33 -- -- -- --

Rifle 144 E. 3rd Ave 24.5 83 0 -- -- -- --

La Plata County

Durango 1235 Camino 

del Rio 23.2 203 0.66 -- -- -- --

Mesa County

Grand 

Junction – 

Powell

650 South Ave 25.3 69 0 9.74

--

59 30.6

GJ 

Continuous - 

Pitkin

645 1⁄4 Pitkin 

Ave 24.5 65 -- 6.12

--

148 --

Clifton Hwy 141 & D 

Road 31.7 147 0 -- -- -- --

Montezuma County

Cortez 106 W. North 

St. -- -- -- 6.75 <3-yr data 19 <3-yr 

data

San Miguel County

Telluride 333 W. 

Colorado Ave 18.4 130 0 -- -- -- --

1 Three year averaging period is representative of 2007-2009.

-- No applicable data available

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Chapter 4 – Environmental Consequences

Table 4.3-33 2010 Western Counties Particulate Monitor Concentrations

PM10 (μg/m3) PM2.5 (μg/m3)

Site Name Location Annual 

Avg.

24-

hr 

Max

3-yr Avg 

Exceedances1

Annual

Avg.

3-yr 

Weighted 

Avg.

24-

hr

Max

3-yr 

Avg

98th

%ile1

Delta County

Delta 560 Dodge St. 23.4 125 0 -- -- -- --

Garfield County

Parachute 100 E. 2nd

Ave 22.5 125 0 -- -- -- --

Rifle 144 E. 3rd Ave 25.5 59 0 -- -- -- --

La Plata County

Durango 1235 Camino 

del Rio 24.8 320 6.1 -- -- -- --

Mesa County

Grand 

Junction – 

Powell

650 South Ave 22.9 155 0 9.3

-- --

34.5

GJ 

Continuous - 

Pitkin

645 1⁄4 Pitkin 

Ave 26.8 171 1 

-- -- -- --

Clifton Hwy 141 & D 

Road 23.0 189 3 -- -- -- --

Montezuma County

Cortez 106 W. 

North St. -- -- -- -- <3-yr data -- <3-yr data

San Miguel County

Telluride 333 W. 

Colorado Ave 19.9 354 3.1 -- -- -- --

1 Three year averaging period is representative of 2008-2010.

-- No applicable data available

CO monitored maximums did not exceed 1.7 ppm and 1.2 ppm. Palisade showed a maximum 

O3 4th high of 0.068 ppm and a three-year average 4th high of 0.067 ppm (Table 4.3-34). 

Table 4.3-34 2010 Western Counties Ozone Monitor Concentrations

Ozone 8-hr Avg (ppm)

Site Name Location 1st

Maximum

4th

Maximum

3-yr Avg of 4th

Max. (2008-2010)

Garfield County

Rifle 195 14th St. 0.069 0.066 0.064

Mesa County

Palisade Water Treatment 865 Rapid Creek Dr. 0.070 0.068 0.067

Montezuma County

Cortez 106 W. North St. 0.076 0.064 0.064

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2011 Compliance

A fourth O3 monitor was added in 2011 at Lay Peak in Moffat County. All particulate monitors 

remained operational from 2010.

Similar to 2010, there were regional dust storms in the Durango and Telluride areas. There 

are two exceptional reports from April 3, 2011 and December 1, 2011 that identify high wind 

events at the Alamosa and Lamar monitoring locations. While the reports do not explicitly 

discuss Durango and Telluride, it states that the prefrontal surface winds were out of a west to 

southwesterly direction and moved over dry soils in Arizona, northwest New Mexico, 

southeast Utah, and southern Colorado producing significant blowing dust. Behind the cold 

front the winds were northerly which moved over dry soils in eastern Colorado, consequently 

also producing significant amounts of blowing dust. This storm system transported PM10 dust 

into the southern and southeastern portions of Colorado. Secondly, both Durango and 

Telluride are more than 175 miles (282 km) south of Craig and the mine. It is unlikely that any 

exceedances from those two sites (Table 4.3-35) would adversely affect the ambient air 

surrounding the mine. Last, the EPA identifies Colorado State AQCR 11 (Garfield, Mesa, 

Moffat, and Rio Blanco counties) as attainment/unclassifiable for PM10 since 1990 (40 CFR 

81.306). 

Table 4.3-35 2011 Western Counties Particulate Monitor Concentrations

PM10 (μg/m3) PM2.5 (μg/m3)

Site Name Location Annual 

Avg.

24-

hr 

Max

3-yr Avg 

Exceedances1

Annual 

Avg.

3-yr 

Weighted 

Avg.1

24-

hr 

Max

3-yr 

Avg

98th 

%ile1

Delta County

Delta 560 Dodge 

St. 21.4 51 0 -- -- -- --

Garfield County

Parachute 100 E. 2nd

Ave 21.3 96 0 -- -- -- --

Rifle 144 E. 3rd

Ave 20.5 54 0 -- -- -- --

La Plata County

Durango2

1235 

Camino del 

Rio

18.1 51 1.3 -- -- -- --

Mesa County

Grand 

Junction – 

Powell

650 South 

Ave 18.6 41 0 -- 8.6 -- 33.5

GJ 

Continuous - 

Pitkin

645 1⁄4 Pitkin 

Ave 23.0 90 0 -- -- -- --

Clifton Hwy 141 & 

D Road 19.9 60 1 -- -- -- --

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PM10 (μg/m3) PM2.5 (μg/m3)

Site Name Location Annual 

Avg.

24-

hr 

Max

3-yr Avg 

Exceedances1

Annual 

Avg.

3-yr 

Weighted 

Avg.1

24-

hr 

Max

3-yr 

Avg

98th 

%ile1

Montezuma County

Cortez 106 W. 

North St. -- -- -- -- 6.3 -- 14.4

San Miguel County

Telluride2

333 W. 

Colorado 

Ave

16.4 68 3.1 -- -- -- --

1 Three year averaging period is representative of 2009-2011. 2 The 2010 exceptional events are included in the three year average exceedances.

-- No applicable data available

CO monitored maximums did not exceed 1.8 ppm and 1.1 ppm. Cortez showed a maximum 

O3 4th high of 0.071 ppm and a three-year average 4th high of 0.066 ppm (Table 4.3-36). 

Table 4.3-36 2011 Western Counties Ozone Monitor Concentrations

Ozone 8-hr Avg (ppm)

Site Name Location 1st Maximum 4th Maximum

3-yr Avg of 4th

Max. (2009-

2011)

Garfield County

Rifle 195 14th St. 0.068 0.066 0.064

Mesa County

Palisade Water 

Treatment 865 Rapid Creek Dr. 0.069 0.066 0.066

Montezuma County

Cortez 106 W. North St. 0.073 0.071 0.066

Moffat County

Lay Peak 17820 CR 17 0.065 0.060 <3-yr data

2012 Compliance

In 2012, CDPHE modified their monitoring region boundaries. The region consists of complex 

terrain including a mix of mountains, plateaus, valleys, and canyons. Grand Junction remains the 

largest city in the region. The Durango-Cortez monitoring sites are no longer included in this 

report as both are now in the southwest region. Also, the Pitkin location in Grand Junction 

contains only a CO monitor. All other monitors remain in the Western Slope network.

The region had one maximum exceedance at the Powell station (Table 4.3-37), but the threeyear average does not exceed 1; thus there is not a PM10 violation.

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 4-51

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Chapter 4 – Environmental Consequences

Table 4.3-37 2012 Western Slope Particulate Monitor Concentrations

PM10 (μg/m3) PM2.5 (μg/m3)

Site Name Location Annual 

Avg.

24-

hr 

Max

3-yr Avg 

Exceedances1

Annual 

Avg.

3-yr 

Weighted 

Avg.1

24-

hr 

Max

3-yr 

Avg

98th

%ile1

Delta County

Delta 560 Dodge St. 24.4 65 0 -- -- -- --

Garfield County

Parachute 100 E. 2nd Ave 18.7 65 0 -- -- -- --

Rifle 144 E. 3rd Ave 19.5 50 0 -- -- -- --

Mesa County

Grand 

Junction – 

Powell

650 South Ave 22.7 176 0.33 -- 7.8 -- 27.9

Clifton Hwy 141 & D 

Road 19.5 74 0 -- -- -- --

San Miguel County

Telluride 333 W. 

Colorado Ave 16.9 80 0 -- -- -- --

1 Three-year averaging period is representative of 2010-2012. -- No applicable data available

CO monitored maximums do not exceed 2.0 ppm and 1.1 ppm. Palisade showed a maximum 

O3 4th high of 0.072 ppm and a three-year average 4th high of 0.068 ppm (Table 4.3-38). 

Table 4.3-38 2012 Western Counties Ozone Monitor Concentrations

Ozone 8-hr Avg (ppm)

Site Name Location 1st

Maximum

4th

Maximum

3-yr Avg of 4th

Max. (2010-2012)

Garfield County

Rifle 195 14th St. 0.078 0.068 0.066

Mesa County

Palisade Water 

Treatment 865 Rapid Creek Dr. 0.075 0.072 0.068

Moffat County

Lay Peak 17820 CR 17 0.072 0.066 <3-yr data

2013 Compliance

The Western Slope monitors remained unchanged from 2012 and results were similar to the 

previous year (Table 4.3-39). 

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Chapter 4 – Environmental Consequences

Table 4.3-39 2013 Western Slope Particulate Monitor Concentrations

PM10 (μg/m3) PM2.5 (μg/m3)

Site 

Name Location Annual 

Avg.

24-

hr 

Max

3-yr Avg 

Exceedances1

Annual 

Avg.

3-yr 

Weighted 

Avg.1

24-

hr 

Max

3-yr 

Avg

98th

%ile1

Delta County

Delta 560 Dodge St. 21.3 64 0 -- -- -- --

Garfield County

Parachute 100 E. 2nd Ave 14.5 29 0 -- -- -- --

Rifle 144 E. 3rd Ave 17.5 46 0 -- -- -- --

Mesa County

Grand 

Junction – 

Powell

650 South Ave 19.2 55 0.33 -- 7.7 -- 28.8

Clifton Hwy 141 & D 

Road 17.6 109 0 -- -- -- --

San Miguel County

Telluride 333 W. 

Colorado Ave 14.6 58 0 -- -- -- --

1 Three year averaging period is representative of 2011-2013.

-- No applicable data available

CO monitored maximums do not exceed 1.5 ppm and 0.9 ppm. Palisade showed a maximum 

O3 4th high of 0.066 ppm and a three-year average 4th high value of 0.067 ppm (Table 4.3-40). 

Table 4.3-40 2013 Western Slope Ozone Monitor Concentrations

Ozone 8-hr Avg (ppm)

Site Name Location 1st

Maximum

4th

Maximum

3-yr Avg of 4th

Max. (2011-2013)

Garfield County

Rifle 195 14th St. 0.065 0.062 0.065

Mesa County

Palisade Water 

Treatment

865 Rapid Creek 

Dr. 0.068 0.066 0.067

Moffat County

Lay Peak 17820 CR 17 0.067 0.065 <3-yr data

Since the mine began operations within the Project Area, there has not been a change in the 

regional attainment designation from the Western Slope counties for PM2.5, PM10, and CO. The 

exceedances that have occurred either at the mine or regionally were primarily due to natural 

phenomena outside the control of Colowyo or other facilities. 

As discussed in Section 4.3.1.4, there are no O3 exceedances regionally of the current 0.075 

ppm standard. The combustion rate of the Craig and Hayden Generating Stations is not 

proposed to change in the foreseeable future; although the precursor emissions are high it does 

not equate to a regional O3 compliance issue. The regional O3 reaction is limited by VOC 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 4-53

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emissions; even large amounts of NOx emissions do not lead to higher O3 concentrations. 

Although the emissions rates for NOx are substantial from the coal combustion, if the regional 

O3 reaction is limited by VOC emissions, even large amounts of NOx emissions do not lead to 

higher O3 concentrations. 

4.3.2.5 Indirect Railroad Emissions

Railroad emissions associated with the Colowyo-owned rail spur were determined for a 

maximum shipping scenario of annual coal tonnage. The emissions are based on the maximum 

number of annual round trips made by the train. Table 4.3-41 includes the quantity of coal 

shipped via rail from the mine from all active mining areas, including the Project Area, from 

2007 to 2014.

Table 4.3-41 Actual Coal Shipped via Rail 2007-2014

Calendar Year Quantity of Coal

Shipped (tpy) 

2007 5,603,387

2008 5,023,737

2009 3,490,157

2010 3,552,630

2011 2,362,725

2012 2,318,968

2013 2,170,905

2014 2,433,433

Table 4.3-42 outlines the maximum criteria pollutant emissions, GHG emissions, and HAP 

estimated emissions that result from rail transport and maintenance from the mine from 2007 

to 2014. 

Table 4.3-42 Railcar and Rail Maintenance Emission Estimates (tpy) 

Source PM10 PM2.5 NOx CO VOC SO2 HAPs GHG1 Black 

Carbon2

Railcar 0.1 0.1 6.3 8.1 0.3 0.03 1.5E-02 3,065 0.1

Rail 

Maintenance 0.1 0.1 0.5 0.5 0.1 0.1 1.5E-02 605 0 

Total 0.2 0.2 6.8 8.6 0.4 0.1 0.03 3,670 0.1

1 Greenhouse gas emissions are presented as CO2e metric tonnes per year. 2 Black carbon is a component of particulate. Therefore, total PM10 and PM2.5 would equate to 0.3 tons/yr, 

respectively with black carbon included.

Rail emissions were also calculated for combustion rates of 2.3 and 5.0 mtpy to account for 

potential future emissions. Criteria pollutant emissions for the lower bound (2.3 mtpy) range 

from 0.1 to 3.30 tons/yr. The range of emissions for the upper bound (5 mtpy) is 0.3-7.2 

tons/yr. Rail maintenance emissions will remain unchanged. Therefore, the maximum 

emissions will be CO at 7.7 tons/yr. 

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All criteria pollutants and HAP emissions associated with railcar activities were compared to 

the county data from the 2011 NEI. Alternative B would contribute a maximum of 0.0139 

percent of all criteria pollutants and 0.0405 percent of all HAPs emitted within Garfield, 

Moffatt, Rio Blanco, and Routt counties. In comparison, the direct emissions from Alternative 

B would be insignificant.

Railroad emissions are far less than many other emissions-generating activities previously 

described. As a result all emissions would be insignificant when compared to statewide totals. 

Colorado emitted 195,455 tons of HAPs in 2001; therefore, the percentage associated with the 

railcars would be 0.000008 percent.

4.3.3 No Action Alternative

4.3.3.1 Direct Emissions Impacts

The No Action Alternative assumes that mining would cease immediately if the Project was not 

approved. An insignificant amount of criteria emissions associated with closure and reclamation 

activities would continue to occur until reclamation is complete 

4.3.3.2 Indirect Combustion Criteria Emissions Impacts

Under the No Action Alternative, criteria pollutant emissions from coal combustion at the 

Craig Generating Station would remain consistent with the current emissions rates. The mine 

would no longer provide coal to the Craig Generating Station; however, there is no indication 

that the station would stop or reduce its power generation. As a result, the station would have 

to source coal from the broader coal market. If this occurred, the total generating rate at the 

Craig Generating Station would remain unchanged. As such, the emissions from the Craig 

Generating Station through 2019 would remain consistent with those reported to CDPHE for 

reporting year 2013 (the most recent available data) (Table 4.3-43). 

Table 4.3-43 Criteria Pollutant Emissions Rates

Location 2013 APENS Annual Actual Pollutant Emissions (tpy) 

PM10 PM2.5 CO NO2 SO2 VOC

Craig Generating 

Station 172.2 121.1 1232.8 12091.0 3261.0 62.2

4.3.3.3 Indirect Coal Combustion GHG and Climate Change Impacts

Under the No Action Alternative, GHG emissions from the Craig Generating Station would 

remain consistent with the current emissions rates. The mine would no longer provide coal to 

the Craig Generating Station; however, there is no indication that the station would stop or 

reduce its power generation. As a result, the station would have to source coal from the 

broader coal market. If this occurred, the total generating rate at the Craig Generating Station 

would remain unchanged. 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 4-55

Mining Plan Modification Environmental Assessment
Chapter 4 – Environmental Consequences

The Craig Generating Station would produce the GHG emissions detailed in Table 4.3-44. 

The calculations assume that the 2014 coal combustion at the Craig Generating Station would 

be a reasonably foreseeable level of combustion. Additionally, the table outlines the amount of

GHG emissions generated from the contracted amount of coal that historically was provided by 

the Colowyo Mine.

Table 4.3-44 GHG Coal Combustion Emissions from the Craig Generating Station

Coal Combusted 

(Short Tons)

CO2

Emissions 

(metric 

tonnes)

CH4

Emissions 

(metric 

tonnes)

Total CH4

in CO2e 

(metric 

tonnes)

N2O 

Emissions 

(metric 

tonnes)

Total 

N20 in 

CO2e 

(metric 

tonnes)

Total 

CO2e 

(metric 

tonnes)

4,604,403 2014 Coal 

Combustion 10,707,403 1,263 31,567 184 54,731 10,793,700 

2,300,000

Current 

Colowyo 

Contract 

Annual 

Maximum

5,348,582 631 15,768 92 27,339 5,391,689 

These values represent the calculated GHG emissions that occurred for the actual combustion 

activities at the Craig Generating Station during 2014 as well as the emissions attributable to 

coal provided from the Colowyo Mine. Under the No Action Alternative, the emissions from 

the Craig Generating Station would remain consistent with these current levels of emissions 

assuming that the same amount of coal is provided from another source than the Colowyo 

Mine. These emissions account for approximately 0.037 percent of estimated global emissions 

and between 0.18 percent of estimated U.S. net emissions. These levels are roughly equivalent 

to the levels that would be generated under Alternatives A and B.

4.3.3.4 Social Cost of Carbon

For the No Action Alternative, indirect GHG and carbon emissions from coal combustion at 

the Craig Generating Station and other regional combustion sources would remain unchanged 

from current emissions levels. As a result, there would be no net change to SCC for the No 

Action Alternative.

4.3.3.5 Ozone Precursor Emission Impacts

Under the No Action alternative, precursors of O3 including NOx and VOCs would still be 

generated by the combustion of coal. Precursor emissions would be generated at Craig 

Generating Station in a manner and at a rate consistent with current facility emissions, assuming 

that the same amount of coal is provided from another source than the Colowyo Mine. 

Table 4.3-45 presents the O3 precursor emissions that were reported for the Craig 

Generating Station to CDPHE for the 2013 reporting year. 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 4-56

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Table 4.3-45 Ozone Precursor Emissions Rates Based on the 2013 Craig 

Generating Station CDPHE Reported Emissions

Coal Combustion Rate (tpy) NO2 (tpy) VOC (tpy) 

4,604,403 12,091.0 62.2

Although the emissions rates for NOx are substantial from the coal combustion, if the regional 

O3 reaction is limited by VOC emissions, even large amounts of NOx emissions do not lead to 

higher O3 concentrations. There would be no emissions factor change (increase or decrease) 

in the production of O3 precursors from any of the alternatives. Therefore, as discussed in 

Sections 4.3.1.4 and 4.3.2.3, regional O3 concentrations would meet appropriate national 

standards. 

4.3.3.6 Indirect Mercury Emissions

Under the No Action Alternative, the Craig Generating Station would continue to operate as 

currently permitted by the State of Colorado and EPA. No change in the electrical generating 

capacity or resultant emissions is anticipated as a result of the No Action Alternative. 

However, the Craig Generating Station would be required to source coal from the broader 

coal market to replace the coal currently provided by the Colowyo Mine.

Mercury emission for the Craig Generating Station was reported by the facility for all 

atmospheric emissions sources as presented in Table 4.3-30. 

As previously described, emissions for the Craig Generating Station have changed significantly 

throughout the period since 2007 and the most recent TRI emissions available. This change is a 

result of the changing regulatory requirements for the facility. Emissions at the Craig 

Generating Station under the No Action Alternative would continue at annual rates similar to 

those detailed in Table 4.3-30. Based on data available from the TRI data explorer, the 

electrical generation sector in Colorado generated approximately 1,070 lbs of mercury 

emissions for reporting year 2013. The contribution of Craig Generating Station to the 

statewide mercury emissions is approximately 3.9 percent, a rate that would remain unchanged 

under the No Action Alternative, assuming that the same amount of coal is provided from 

another source than the Colowyo Mine. 

4.3.3.7 Rail Car Emissions Impacts

Under the No Action Alternative, no coal would be transported from the mine. As a result, no 

emissions would be generated by rail travel or maintenance associated with coal transport from 

the mine.

4.3.4 Mitigation Measures

Air Quality Mitigation Plan

As part of Construction Permit No. 95MF1040, and No. 06RB131, Colowyo is required to 

submit an Air Quality Dust Mitigation Plan to the state. Colowyo has submitted a Dust Mitigation 

Plan and its receipt was acknowledged by APCD on May 27, 2010. The plan is pending approval of a 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 4-57

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Chapter 4 – Environmental Consequences

permit revision based on an ongoing ambient air quality analysis. Dust control practices currently 

utilized at Colowyo include, but are not limited to:

• Topsoil and overburden material is watered as necessary during the removal process to control 

fugitive dust.

• Topsoil stockpiles are re-vegetated within one year.

• Vehicle speed on unpaved haul roads is limited to a maximum of 45 mph. Speed limit signs 

are posted. 

• Unpaved haul roads are watered as often as needed to control fugitive dust. 

• Magnesium chloride or other similar dust suppressants are applied to unpaved haul 

roads for fugitive dust control.

• Hood and/or water spray units are utilized during overburden and coal drilling to 

minimize dust.

• In response to elevated readings of PM10 at the TEOM continuous monitors, the mine 

site institutes operational shutdown procedures. Operational shutdown will remain in 

effect until climatic conditions improve. 

4.4 GEOLOGY

4.4.1 Alternative A – Proposed Action, PR02 as Approved in 2007

Alternative A would result in the removal of the recoverable coal in the South Taylor pit. Coal 

seams that would be mined via truck/shovel, dragline, and highwall miner techniques include the 

X and A through G789 seams (a stratigraphic depiction of the coal seams can be found in KEC 

[2005]). At the assumed production rate of 5.8 to 6 mtpy, up to 60 mt of coal would 

eventually be mined. This would result in obliteration of the geological column within the pit 

footprint; this effect would be a permanent effect on geologic resources within the Project 

Area. However, the Colowyo Mine coal removal would only remove a small portion of the 

geologic column and coal reserves associated with the Danforth Hills coal field, and an even 

smaller portion of the Rocky Mountain Coal Province of Tully, which contains the Danforth 

Hills coal field. Therefore, the effect would be negligible to minor but would be long term. At 

the end of mine life, the pit would be backfilled as part of closure and reclamation. 

4.4.2 Alternative B – PR02 as Revised

4.4.2.1 Previous Impacts

The portion of PR02 completed to date has resulted in the removal of much of the recoverable 

coal in the South Taylor pit. Coal seams that have been mined via truck/shovel, dragline, and 

highwall miner techniques include the X34, A, B12, C35, D12, E2, F1, F356, Fab, G3, and G78 

seams. Since 2008, Colowyo has mined between 1.2 and 1.8 mtpy from the South Taylor pit, 

for a total of about 10 mt. Removal of the coal in the Project Area has resulted in the 

obliteration of the geological column within the pit area as coal is removed.

4.4.2.2 Potential Impacts

As mining of the South Taylor pit continues, the pit would be enlarged minimally in areal extent, 

and volume to a greater extent. At the assumed production rate of 2.5 mtpy under Alternative 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 4-58

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B, 11.8 mt of additional coal would eventually be mined. The impact on geological resources 

would be negligible. 

4.4.3 No Action Alternative

Under the No Action Alternative, no mining would occur within the Project Area beyond 

September 2015. Impacts to the geological resources were incurred as a result of the mining 

activity and therefore under this alternative, geological resources in the area would remain as

described in Section 4.4.2.1. Minor volumes of material would be removed or disturbed as a 

result of the reclamation activity and this activity would occur eventually (although at a later 

date) regardless of alternative. 

4.4.4 Mitigation Measures

No mitigation measures would be necessary for geology. 

4.5 WATER RESOURCES

4.5.1 Alternative A – Proposed Action, PR02 as Approved in 2007

Under Alternative A, the South Taylor pit, the West Taylor valley fill, and the East Taylor valley 

fill (Figures 3-5a and 3-5b) would physically disrupt the uppermost channel reaches of Taylor 

Creek and its headwater tributaries. This physical disruption would be to non-perennial 

channel reaches and would occur through excavation or fill placement, rendering the channel 

nonfunctional in those locations. Further, a sediment pond (Figures 3-5a and 3-5b) would be 

constructed across Taylor Creek just downstream of the West Taylor fill. In addition to the 

direct Taylor Creek channel disturbances, Alternative A would disturb the upper portion of the 

West and East Taylor watersheds (Figures 3-5a and 3-5b) (597 and 88 acres, respectively) 

and additional acreage (503 acres) within the Good Spring Creek watershed (Figures 3-5a and

3-5b). The only direct channel disturbances in the Good Spring Creek watershed would be 

within the headwater portions of small tributary channels where the pit would disrupt the 

drainage and where sediment ponds and diversions would be constructed. Additionally, several 

small springs and seeps would be disrupted by disturbances in the Taylor Creek and Good 

Spring Creek watersheds. Mining under Alternative A would not result in any disturbances of 

the Wilson Creek channel, its watershed, or springs within its watershed.

Channel disruptions, direct spring disturbances in the footprint which would eliminate several 

springs, potential indirect spring flow disruptions due to draining, and watershed disturbances 

could alter the local runoff characteristics and flow patterns in Taylor Creek and Good Spring 

Creek. Colowyo (2007) predicted that base flow in Good Spring Creek would be reduced by 

up to 7 percent during and for 45 years after mining, and that base flows in Taylor Creek would

not be reduced. Overall, this would be expected to be negligible because: 1) of the headwater 

positioning of the disturbed area and the nature of the non-perennial flows, 2) the nonpermanent nature of any reductions; and 3) because Colowyo has committed to avoiding 

reductions in base flows by not exercising their water rights if necessary (Colowyo 2007). 

CDRMS (2007; 2010) findings support this determination in that they found there would be no 

changes to the overall hydrologic balance.

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 4-59

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The mining plan decision document for PR02 as Approved in 2007 (OSMRE 2007) included 

memoranda from USFWS discussing the water depletion associated with Alternative A. It 

described an annual water depletion of an additional (i.e., new) 27 acre feet that would result 

from the four new sediment ponds associated with PR02 as Approved in 2007. This depletion 

would not represent a true diversion, but it would remove a small proportion of water from 

the Yampa River watershed. Further, water for mining and related industrial activities would 

continue to be diverted under decreed water rights from Good Springs Creek and Milk Creek 

to Wilson Reservoir, as it currently is, for PR02 as Approved in 2007. This would be a 

continuing impact that was already occurring at the mine, but would be longer in time. Actual 

channel diversions associated with Alternative A would route flows around disturbances or 

through reclaimed lands; their use requires CDRMS approval, and as such, are designed in a 

manner that would not diminish downstream water rights (CDRMS 2007). Overall, these 

mining-related depletions and diversions associated with Alternative A would result in a 

negligible impact to water quantity in the Yampa River. 

In addition to the mining-related diversions, the Craig Generating Station diverts water from 

area surface waters in much greater quantities than does the mine, which could be an indirect 

impact. That water comes from the Yampa River and the Elkhead Reservoir, as allowed by 

water rights, and transports that water to the plant where it is recycled for reuse in their 

process to the extent possible (Tri-State 2015b). It may also come from the Stagecoach 

Reservoir, if needed (CWCB 2009). Those plant-related diversions averaged about 12,000 

acre-feet per year between 1980 and 2014 (CDSS 2015) and occur as allowed by valid water 

rights. During that same period, the mean of the average annual flows in the Yampa River (at 

USGS Station 09251000, Yampa River near Maybell, downstream of the plant and the mine) was 

1,570 cfs (1.1 million acre-feet per year) (USGS 2015b). In addition, the Yampa River flows 

including the effects of diversions are considered in various management plans (CWCB 2009; 

CWCB 2012; CDW 2010). Further, there is an instream flow water right on the Yampa 

between Elkhead Creek and the confluence with the Green River (CWCB 2015), which also 

reduces potential effects from any diversions. Overall, the ongoing and continuing diversions 

would result in a negligible indirect impact to water resources in the area. 

Transporting water associated with both the Craig Generating Station and with the mine is, and 

would continue to be, accomplished via buried pipeline. There would be no impacts associated 

with this transport because the flow is managed, contained, and there are no plans to 

reconfigure the pipeline (i.e., no additional disturbance). 

The retention of the large majority of runoff produced on mine-disturbed land would protect 

downstream water quality. Any inadvertently spilled (e.g., during coal transport) or leaked 

fluids (i.e., hydrocarbons) as well as any coal fines, salts, or sediments (including iron-bearing 

components) transported by runoff would be properly contained and cleaned up, with 

reporting to appropriate agencies as required. Other BMPs (e.g., lined structures, spill training, 

berms) would reduce the potential for such incidents to occur. Further, operational water 

monitoring at some of the sites shown in Figures 3-5a and 3-5b would also enable tracking of 

water quality to identify any unforeseen issues, which could then be rectified. Overall, the 

combination of structural and non-structural BMPs would reduce potential surface water 

quality impacts due to spills and erosion to negligible levels. 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 4-60

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Groundwater impacts under Alternative A would include the interception and disruption of any 

small perched aquifers within the pit footprint. There would also be the potential for draining 

of spring flows near the pit. Due to their nature they are isolated small features, and their 

contribution to the overall hydrologic balance would be to supporting stream flow, which was 

analyzed within the flow reduction impact described above. Impacts to the regional bedrock 

aquifer would not be expected due to the distance between the ultimate pit bottom and the 

potentiometric surface (Colowyo 2007; CDRMS 2007; CDRMS 2010). The potentiometric 

surface of the uppermost regional aquifer underlies the lowest coal seam to be mined by 

approximately 590 feet. Impacts to the alluvial aquifer would not be expected (Petersen 

Hydrologic, LLC 2015). Petersen Hydrologic, LLC (2015) based their assessment on several 

factors, including in part: 1) finding no evidence of past impact to that aquifer from mining- and 

reclamation-related activities at the mine; and 2) finding that the recharge potential is low due 

to the mine’s location in an upland area. Combined, impacts to groundwater resources would 

be negligible to minor.

Regarding the elevated iron concentrations in the Yampa River discussed previously in 

Section 3.5, little data are available to directly determine the potential for contributions from 

Alternative A, related coal transportation, or the Craig Generation Station. However, as 

described in Section 3.5, monitoring in Wilson, Taylor, and Good Spring creeks under the 

baseline conditions showed that total recoverable iron concentrations were often below the 

EPA aquatic life standard of 1.0 mg/L, but individual analyses were often greater than the 

standard, particularly in Wilson Creek (Colowyo 2007). Compliance records for Colowyo's 

existing NPDES permit can also be used to ascertain whether or not there have been impacts 

to downstream surface waters. This permit regulates surface water runoff collected from the 

mine area and contains effluent limitations for any discharge of these waters. This regulatory 

oversight helps to ensure that impacts to downstream water quality do not occur. 

Implementation of Alternative A would require that Colowyo comply with all effluent limits in 

their NPDES permit for all discharges from the disturbed areas and these limits would include 

iron limits as well as total suspended solids (TSS) limits. Management and/or treatment of TSS 

(e.g., via sediment ponds) and retention of storm water would help to ensure that iron bound 

within soil/sediment particles would not be released to receiving waters in concentrations 

exceeding limitations. Should iron-impacted waters be generated and need to be released, 

effluent limits would have to be met, and, if sediment ponds or other passive treatment 

measures are not effective Colowyo would be required to implement treatment. The Craig 

Generation Station would also be required to comply with their NPDES effluent limits for any 

discharges, and these limits include iron. There would be no reason to expect that this facility 

would not be able to meet its iron limit, based upon past history (EPA 2015b). Overall, iron 

loadings would likely be negligible.

Colowyo analyzes dissolved mercury concentrations in groundwater and surface water samples 

collected as part of their mine permitting requirements. Data prior to 2007 is summarized in 

Table 4.5-1. Almost all of those data range from 0.0001 to 0.001 mg/L and in all likelihood are 

actually less-than-laboratory reporting levels rather than true concentration variations, based 

upon an analysis of the Colowyo data (Colowyo 2015) and a review of the current laboratory 

reporting limits (Inter-Mountain Labs (IML) 2015). Neither the mine’s nor the Craig Generating 

Station’s NPDES permit has an effluent limit for mercury. The State of Colorado chronic 

aquatic life water quality standard for mercury is 0.01 micrograms per liter (0.00001 mg/L) 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 4-61

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(CDPHE 2012b). Because the data reported by Colowyo have reporting levels that are greater 

than the standard, with all values less than those reporting levels, it is not possible to determine 

the degree to which, if any, the mine has in the past or would in the future under Alternative A 

contribute mercury to the Yampa River. As noted in Section 3.5, airborne mercury 

deposition can come from multiple sources, natural and human-caused, near and far. It is not 

possible to determine, with the information at hand, the proportion of mercury in Project Area 

streams or in the Yampa River that has or would result from this alternative directly or 

indirectly considering the Craig Generating Station. However, as discussed above in Section 

4.3 mercury would be released under Alternative A; and as such, some amount of this could be 

deposited in the Yampa River with some incremental addition to the baseline mercury 

concentrations. This amount cannot be quantified with available information; however, the 

resultant effect on fish has been determined to be moderate (Section 4.8). 

Table 4.5-1 Summary of Pre-2007 Water Monitoring Data for Selected Parameters

Site ID1

Sampling 

Period 

(PreTDS Iron (Fe) 

(dissolved)

Mercury (Hg) 

(dissolved)

Selenium (Se) 

(dissolved)

2007) N2 mg/L N2 mg/L N2 mg/L N2 mg/L

Groundwater

A-6 

1984-2006 

for TDS, Hg 

and Se; 

1996-2006 

for Fe

63 180-930 39 0.01-

1.82 62 0.0001-

0.0165 62 0.001-

0.007

Gossard_14 1983-2006 35 962-

1810 35 0.01-29 35 0.0001-0.01 35 0.00-0.017

NGSW

1989-2006 

for TDS, Hg

and Se; 

1996-2006 

for Fe

70 780-

1890 37 0.01-

0.46 70 0.0001-

0.001 70 0.001-

0.015

Surface Water

NUGSC 1992-2006 59 360-

1610 78 0.01-8.54 67 0-0.001 67 0.001-0.36

LGSC 1982-2006 135 630-

4050 122 0.03-4.27 115 0.0001-0.001 115 0.001-0.03

LTC 1983-2001 59 144-

1930 59 0.01-132 55 0.0001-0.001 55 0.001-0.016

1

See Figures 3-5a and 3-5b for Locations 2

n=number of observations

Colowyo analyzes dissolved selenium concentrations in groundwater and surface water samples 

collected as part of their mine permitting requirements. Data prior to 2007 is summarized in 

Table 4.5-1. Groundwater data collected generally quarterly from three wells in or near the 

Project Area showed selenium concentrations ranging from 0.001 mg/L to 0.017 mg/L. There 

was no pre-2007 data for the other groundwater monitoring sites. Surface water data were

also collected generally quarterly; data from a site in lower Taylor Creek (site LTC) has 

consistently been at 0.005 mg/L (again, likely the reporting level), while data from sites in Good 

Springs Creek has been more variable. Lower Good Springs Creek (site LGSC) had a minimum 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 4-62

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Chapter 4 – Environmental Consequences

concentration of 0.001 mg/L and a maximum selenium concentration of 0.03 mg/L, and North 

Upper Good Springs Creek (site NUGSC) selenium concentrations ranged from 0.001 mg/L to

0.036 mg/L. There was no pre-2007 data for the other surface water monitoring sites. Neither 

the mine’s nor the Craig Generating Station’s NPDES permit has an effluent limit for selenium. 

The chronic aquatic life standard for selenium is 0.005 mg/L (CDHPE 2012b), and the above 

record indicates that selenium pre-2007 was already higher than this standard.

The analysis shows that the effects on surface water quality would be limited to increased TDS 

in the base flow of Good Spring Creek. The (expected and worst case) analyses predict

increases between 1.6 and 13.5 percent, with a composition dominated by increasing sulfate 

ions, over the course of several hundred years after the completion of mining (Colowyo 2007). 

Colowyo (2007) predicted the duration of the elevated TDS using saturation indices for 

groundwater samples from Project Area wells and spoils borehole geochemical data. The focus 

of the analysis was on sulfate, the relevant component of TDS that could potentially increase. 

Using the exhaustion time for pyrite, which would be the source of the sulfate, as well as the 

volume of the pile available, they derived estimates of the duration of the elevated TDS 

discharge ranging from 110 to 450 years (Colowyo 2007).

Reclamation bonding requirements as well as NPDES requirements would ensure that water 

quality is maintained throughout the reclamation phase of Alternative A. Over the long term, 

final reclamation would further reduce the potential for water quality impacts. Pits that have 

been backfilled after mining would result in surfaces that approximate the pre-mining 

topography and that are covered with topsoil and revegetated. During reclamation, drainage 

patterns would be re-established per the approved reclamation plan and the potential for water 

quality impacts would be further reduced in part because there would be less potential for 

erosion and spills. As per the reclamation plan and the PAP for PR02 as Approved in 2007,

acid-forming waste is not an issue at the mine (Colowyo 2007); thus, there would not be a 

potential for acid-mine discharge to either surface water or groundwater. Backfilled pit 

surfaces and reclaimed spoil areas are designed (e.g., by grading and sloping measures) to 

reduce the potential for infiltration and percolation of meteoric water that could eventually 

pick up salts and reach alluvial aquifers and or downstream surface waters (Petersen Hydrologic 

LLC 2015). Any increase in the resultant dissolved solids concentrations in Wilson, Taylor, or 

Good Spring creeks would be negligible to minor (Colowyo 2007).

CCRs generated at the Craig Generating Station as part of the coal combustion process are 

placed into a CCR disposal site at the Trapper Mine. The disposal site is under the jurisdiction

of SMCRA and is approved to receive CCRs under a Certificate of Designation from Moffat 

County, with regulatory oversight from CDPHE. The disposal site, CCR placement 

requirements, design features, operating criteria, monitoring and corrective action; closure and 

post-closure monitoring standards; and record-keeping and reporting requirements are 

regulated under SMCRA and CDHPE. Further, groundwater monitoring of the site has 

determined that metals of concern are present in low levels; however, limited permeability and 

infiltration has kept these concentrations to those observed elsewhere at the mine. Therefore, 

the potential indirect impact to groundwater as a result of the disposal of CCRs at the Trapper 

Mine is negligible. 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 4-63

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Overall, potential impacts to water resources under Alternative A are expected to be negligible 

to minor.

4.5.2 Alternative B – PR02 as Revised

4.5.2.1 Previous Impacts

The South Taylor pit, the West Taylor valley fill, and the East Taylor valley fill have physically 

disrupted the uppermost channel reaches of Taylor Creek and its headwater tributaries. This 

physical disruption has been to ephemeral or intermittent channel reaches and has occurred 

through excavation or fill placement, rendering the channel nonfunctional in those locations. 

Further, a sediment pond has also been constructed across Taylor Creek just downstream of 

the West Taylor fill. In addition to the direct Taylor Creek channel disturbances, mining under 

Alternative B has disturbed approximately 650 acres within the upper portion of the West 

Taylor watershed. Similarly, the pit excavation has disturbed approximately 140 acres within 

the Good Spring Creek watershed. The only direct channel disturbances in the Good Spring

Creek watershed have been in two small tributary channels where sediment ponds and 

diversions have been constructed. Additionally, several small springs and seeps have been 

disrupted by disturbances in the Taylor Creek and Good Spring Creek watersheds. While 

springs (Figures 3-5a and 3-5b) were inventoried and mapped during baseline data gathering, 

they have not been included in water monitoring programs; thus, quantifying the previous 

impact of their disruption (direct or indirect) is not feasible. Mining under Alternative B has not 

resulted in any disturbances of the Wilson Creek channel, its watershed, or springs within its 

watershed.

Channel and spring disruptions and watershed disturbances may have altered the local runoff 

characteristics and flow patterns in Taylor Creek and, to a lesser extent, Good Spring Creek. 

While there are no flow monitoring records for any of the springs shown on Figures 3-5a and 

3-5b, there are flow records for pre- and post-2007 at three of the surface water monitoring 

stations shown. Based upon a review of water monitoring records (Table 4.5-2), changes in 

runoff characteristics and flow patterns cannot be confirmed with a simple statistical analysis 

due to the nature of the data sets. However Colowyo’s analysis of the same data (Colowyo 

2015) reports declining trend lines over time for both LTC and LGSC, and a slightly increasing 

trend line for NUGSC.

Table 4.5-2 Stream Flow Data Summary

Pre-2007 Flow Data Post-2007 Flow Data

Site ID1 N2 Min

(cfs)

Max

(cfs)

Avg

(cfs)

N2 Min

(cfs)

Max

(cfs)

Avg

(cfs)

NUGSC 162 0.20 20 3.0 32 0.06 19.5 2.9

LGSC 281 0.06 47 4.1 32 0.49 22 3.8

LTC 169 0 6.3 0.4 32 0 1.2 0.7

1

See Figures 3-5a and 3-5b for locations 2

n=number of observations

The monitoring records (Colowyo 2015) (Tables 4.5-1 and 4.5-3) also indicate that TDS may 

have increased in lower Taylor Creek (site LTC) compared to the records from the 1980s and 

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1990s. Colowyo’s analysis of the same data (Colowyo 2015) shows a strong trend line for 

LTC, as well. However, it is important to note that LTC is located not only downstream of the 

South Taylor operations but downstream of the other Colowyo operations as well. TDS 

concentrations in Good Spring Creek (LGSC and NUGSC) exhibit wide seasonal variations and 

any overall trend cannot be determined with simple statistics. Colowyo’s analysis of the same 

data (Colowyo 2015) reports increasing trend lines over time for both LGSC and NUGSC.

Table 4.5-3 Summary of Post-2007 Water Monitoring Data for Selected 

Parameters

Site ID1

Sampling 

Period 

(PreTDS Iron (Fe) 

(dissolved)

Mercury (Hg) 

(dissolved)

Selenium (Se) 

(dissolved)

2007) N2 mg/L N2 mg/L N2 mg/L N2 mg/L

Groundwater

A-6 2008-2014 28 630-730 28 0.05-

1.23 28 0.001-

0.001 28 0.002-

0.005

A-7 2008-2014 27 990-

2100 27 0.05-0.1 27 0.001-0.001 27 0.005-0.042

A-8 2008-2014 23 620-

2040 23 0.05-

0.36 23 0.001-

0.001 23 0.005-

0.035

Gossard_14 2008-2014 28 1500-

1800 28 0.05-0.07 28 0.001-0.001 28 0.005-0.008

NGSW 2008-2014 28 1640-

2100 28 0.05-

0.13 28 0.001-

0.001 28 0.005-

0.005

MT-95-02 2008-2014 28 2020-

2330 28 0.05-0.06 28 0.001-0.001 28 0.005-0.01

Surface Water

NUGSC 2008-2014 28 770-

1550 28 0.05-4.13 28 0.001-0.001 28 0.005-0.02

LGSC 2008-2014 28 870-

1910 28 0.15-

8.84 28 0.001-

0.001 28 0.005-

0.015

UWFGSC 2008-2014 28 380-910 28 0.05-7.9 28 0.001-

0.001 28 0.005-0.016

LTC 2011-2014 10 1440-

2910 10 0.07-

2.72 10 0.001-

0.001 10 0.005-

0.005

1

See Figures 3-5a and 3-5b for locations 2

n=number of observations

While with any similar operation, there is always the potential for an inadvertent spill or release 

(e.g., hydrocarbons) that could reach a stream channel and affect water quality, this has not 

happened with this Project to date, based upon information provided in personal 

communications with Colowyo (T. Tennyson, personal communication, June 18, 2015). Colowyo 

has implemented a spill prevention, control, and countermeasures (SPCC) plan to prevent or minimize 

the impact of spills that may occur.

Colowyo’s NPDES permit includes three outfalls relevant to the Project (Figures 3-5a and 3-

5b). Since 2007, discharge of stormwater has not occurred at Outfall 009 (Section 16 pond, 

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which treats runoff from the South Taylor area) and has only occurred once (in 2011) at Outfall 

012 (Section 28 pond) when all effluent limits were met. Thus, there is no evidence to suggest 

that the receiving stream (Good Spring Creek) for either of these outfalls had its water quality 

impacted by the Project. Outfall 011 (West Taylor pond) drains to Taylor Creek. This outfall 

discharges nearly continuously as a result of a rock underdrain constructed in the pre-mine 

drainages that the permanent fill is placed in. According to personal communications with 

Colowyo (T. Tennyson, personal communication, July 18, 2015), the drain captures water from 

several springs beneath Colowyo’s disturbance footprint, as well as, potentially, some water 

collected in the pit. Generally, effluent limits are met at this outfall, though there have been 

rare exceedances of total iron and TSS limits under PR02 as Revised (described below). 

Outfall 011’s effluent limit for total recoverable iron is a 30-day average of 1.0 mg/L. This limit 

was exceeded at Outfall 011 once in 2008 (5.36 mg/L) and once in 2012 (1.21 mg/L) (EPA 

2015b). These occurred in conjunction with higher than normal TSS concentrations. They 

likely represent an iron component to the particulates and were associated with storm events 

(storm runoff)

10. More than 90 percent of the iron data reported from the near-continuous 

discharge of Outfall 011 shows iron concentrations of well below the NPDES permit limit. The 

NPDES permit is the means by which the state tracks Colowyo’s compliance with the Clean 

Water Act. These isolated past exceedances are not likely to have resulted in any sustained 

impact to water quality in the Taylor Creek drainage or to waters further downstream (Table 

4.5-3). 

Dissolved mercury concentrations in streams monitored in or near the Project Area are all 

reported as 0.001 mg/L, which is likely to represent the reporting level rather than a true 

concentration (Table 4.5-3). Because this reporting level is greater than the aquatic life water 

quality standard, it is not possible to determine the degree to which, if any, Alternative B has 

contributed mercury to the Yampa River. Similar to Alternative A, Section 4.3 explains that 

mercury has been released airborne; and as such, some amount of this could have been 

deposited in the Yampa River with some incremental contribution to its mercury 

concentrations. This amount cannot be quantified with the information at hand; however, the 

resultant effect on fish has been determined to be the same as for Alternative A (i.e., moderate 

[Section 4.8]). 

Dissolved selenium concentrations in streams that have been monitored during the 

implementation of Alternative B are summarized in Table 4.5-3. They are all at or greater 

than the chronic aquatic life criterion. However, it is likely that the minimum values of 0.005 

mg/L represent less than reporting levels; further, the baseline condition (Table 4.5-1) reports 

maximum selenium concentrations that are greater than would occur under Alternative B. 

Based upon this assessment, selenium impacts are unlikely to have occurred. 

Several of the wells shown on Figures 3-5a and 3-5b have been monitored both prior to 2007

and during operations. Those data for some of the key constituents are summarized in Tables 

4.5-1 and 4.5-3. While a complete statistical analysis of this information would be complicated, 

10 CDPHE recently corrected improperly coded storm runoff data in EPA’s database and applied the appropriate alternative 

effluent limits. Applying the alternate limit removed the iron and TSS limit exceedances in these instances (K. Morgan, 

personal communication, July 29, 2015).

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Colowyo’s analysis of the same data (Colowyo 2015) indicates that TDS has shown a likely 

negligible trend at A-6, a strong upward trend at Gossard Well (which is also down gradient of 

other Colowyo operations that were permitted prior to PR02), and a noticeable upward trend 

at NGSW. CDRMS (2010) notes that groundwater in the Yampa River watershed can have 

elevated concentrations of selenium and iron, among other constituents.

Other than an unquantifiable amount of groundwater discharging from perched aquifers of 

limited extent (the springs and seeps mentioned above, which have not been monitored) that 

have been disrupted under Alternative B, the South Taylor pit has not intercepted 

groundwater. This is because the potentiometric surface of the uppermost regional aquifer 

underlies the lowest coal seam to be mined by approximately 590 feet. CDRMS (2007) has 

determined that Colowyo did not need any points of compliance in the bedrock aquifer 

because there was no potential for it to be negatively impacted by the coal mining and 

reclamation activities within either the Project Area or the other ongoing operations. The 

regional bedrock aquifer is associated with the Trout Creek Sandstone; smaller perched 

aquifers are associated with the Williams Fork Formation. Conversely, CDRMS (2007) also

determined that the alluvial groundwater systems along Wilson, Taylor, and Good Spring 

creeks might potentially be impacted. Permit stipulation 7 required Colowyo to analyze that 

potential (CDRMS 2007). To that end, Petersen Hydrologic, LLC (2015) recently examined 

surface water and groundwater data and evaluated whether or not Colowyo’s activities had 

impacted alluvial groundwater and whether or not impacts would be likely in the future. In a 

report not yet submitted to CDRMS, Peterson Hydrologic found “no evidence to conclude that 

significant impacts to water quality in the alluvial groundwater systems resulting from miningand reclamation-related activities at the Colowyo Mine have occurred” (Petersen Hydrologic, 

LLC 2015). The disposal of CCRs at the Trapper Mine has not resulted in degradation of 

groundwater above groundwater standards.

4.5.2.2 Potential Impacts

Continuing PR02 as Revised activities under Alternative B would not result in any additional 

channel or spring/seep disruption. These activities would only disturb an additional 

approximately 20 acres, which would all be within the upper portion of the West Taylor 

watershed. This incremental addition to the disturbed area would not cause any further 

alteration to local runoff characteristics and flow patterns in Taylor Creek beyond that which 

have already occurred. Sediment ponds that are currently in place would continue to treat 

runoff and prevent downstream sedimentation. Further, the NPDES permit would continue to 

be in effect, and based upon past records, future compliance with effluent limitations would be 

expected. The past direct and indirect impacts of water diversions and water transport would 

be similar to those under Alternative A.

The retention of the large majority of runoff produced on mine-disturbed land would continue 

to protect downstream water quality. Any inadvertently spilled or leaked fluids (i.e., 

hydrocarbons) as well as any coal fines, salts, or sediments transported by runoff would be 

properly contained and cleaned up, with reporting to appropriate agencies as required. Other 

BMPs would reduce the potential for such incidents to occur. Overall, the combination of 

structural and non-structural BMPs would reduce potential surface water quality impacts due to 

spills and erosion to negligible levels. 

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As described above, no additional loss of springs or seeps would be anticipated as a result of 

Alternative B, nor would additional interception of small perched aquifers be likely. Further, for 

the same reasons as described above, impacts to the regional bedrock aquifer are not expected. 

Due to the lower production rate and tonnage mined, Colowyo coal would represent less of 

the coal combusted at the Craig Generating Station, and therefore would contribute to less 

CCR disposal than under Alternative A. This would remain a negligible indirect effect. Future 

impacts to the alluvial aquifer would not be expected (Petersen Hydrologic, LLC 2015).

Over the long term, final reclamation would commence and effects would be equivalent to 

Alternative A. 

Overall, potential impacts to water resources under Alternative B are expected to be negligible 

to minor.

4.5.3 No Action Alternative

Under the No Action Alternative mining would cease, and closure activities would commence. 

There would be no further disruption of Project Area stream channels, and no further effects 

to downstream flows or quality beyond those described in Section 4.5.2.1. Similarly, there 

would be no additional loss of springs or interception of groundwater. The reclamation plan 

would be implemented in a way to avoid excessive sediment loading, as well as loading of other 

parameters, even after the ponds no longer exist. The past direct and indirect impacts of water 

diversions and water transport would be similar to those under Alternatives A or B, but the 

indirect effects of water diversion from the mine would cease sooner. Impacts during and after 

reclamation would be the same as those described for the previous impacts, but would occur 

sooner than under Alternatives A and B.

Overall, potential impacts to water resources under the No Action Alternative are expected to 

be negligible to minor.

4.5.4 Mitigation Measures

No mitigation measures would be necessary for water resources. 

4.6 VEGETATION

4.6.1 Alternative A – Proposed Action, PR02 as Approved in 2007

Under Alternative A, 1,181 acres of previously undisturbed vegetation would be disturbed 

gradually as land is cleared for mining activities. These impacts would be short term and would 

range from negligible (riparian type) to major (aspen type) within the Project Area until 

reclamation replaced vegetation to approved reclamation plan (or improved) conditions (Table

4.6-1). Alternative A would also disturb 261 acres of previously disturbed land and 115 acres 

of land under partial or final reclamation from previously approved operations. 

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Table 4.6-1 Impacts to Previously Undisturbed Vegetation, Alternative A

Vegetation Type1 Acres Disturbed2 

Percent of Vegetation Type 

Disturbed within the 

Project Area3

Mountain Shrub 715.8 18

Aspen 202.0 69

Sagebrush 236.7 10

Bottomland 21.8 27

Grassland 6.2 12

Pond 3.5 58

Riparian 1.0 3

Total 1187 1 Vegetation types include vegetation as well as other land cover classifications. 2 May not sum to exact disturbance due to rounding. 3

See Table 3.6-1 in Chapter 3 for acres of each vegetation type within the 7,115 acre Project 

Area. 

Similar to what has already occurred in reclaimed portions of the Project Area, impacts to 

vegetation would be lessened by the implementation of design features (Section 2.2.3). These 

measures would include restoration of disturbed areas to the approved reclamation plan 

conditions, which include targets for improvement beyond existing conditions for other 

resources (e.g., wildlife or GSG habitat [Section 4.9.1]). Several growing seasons would be

needed for revegetated areas to be restored to the PR02 as Approved in 2007 vegetation 

standards (Section 4.15 in Colowyo [2007]). Colowyo would continue to monitor reclaimed 

areas until they are released from bond liability.

Implementation of these measures would limit the potential impacts from the establishment of 

noxious or invasive species with the continued application of herbicides as described in the 

weed control plan in PR02 as Approved in 2007 (Colowyo 2007). Additionally, design features 

include protection afforded to vegetation resources from potential fugitive dust or spills of 

petroleum or other fluids from equipment.

4.6.2 Alternative B – PR02 as Revised

4.6.2.1 Previous Impacts

Table 4.6-2 describes the previous impacts to the various vegetation types within the Project 

Area.

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Table 4.6-2 Previous Impacts to Previously Undisturbed Vegetation, Alternative B

Vegetation Type1 Acres Disturbed2 

Percent of Previously 

Disturbed Vegetation Types 

within the Project Area3

Mountain Shrub 418.4 12

Aspen 186.1 64

Sagebrush 150.8 6

Bottomland 21.1 26

Grassland 9.7 19

Pond 3.5 58

Riparian 0.7 22

Total 790.3 1 Vegetation types include vegetation as well as other land cover classifications.

2 May not sum to exact disturbance due to rounding.

3

See Table 3.6-1 in Chapter 3 for acres of each vegetation type within the 7,115 acre Project 

Area. 

Impacts to vegetation in the Project Area have been lessened by the implementation of design 

features (Section 2.2.3), primarily associated with approximately 66 acres of reclamation. To 

date, there have been no reported infestations of noxious weeds or impacts to vegetation from 

spills or fugitive dust in the Project Area. 

4.6.2.2 Potential Impacts

Alternative B would result in short-term, negligible to minor impacts to vegetation until 

reclamation replaced vegetation to the approved reclamation plan conditions. The 20 acres of 

remaining disturbance under Alternative B would occur in the mountain shrub, aspen, and 

bottomland vegetation communities. The same design features (Section 2.2.3) and 

reclamation goals (Section 4.15 in Colowyo [2007]) would be applied as those under 

Alternative A. 

4.6.3 No Action Alternative

Under the No Action Alternative, the additional disturbance (20 acres) would not occur. The 

previously disturbed areas would be reclaimed in accordance with the approved reclamation 

plan (Appendix B). While the reclamation would occur in the same manner as Alternatives A 

and B, the No Action Alternative would result in reclamation being completed earlier. 

4.6.4 Mitigation Measures

No mitigation measures would be necessary for vegetation. 

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4.7 WETLANDS

4.7.1 Alternative A – Proposed Action, PR02 as Approved in 2007

Small wetlands that total 2.12 acres would be impacted under activities associated with 

Alternative A. Colowyo would have to obtain a USACE 404 Permit prior to disturbing those 

wetlands and would likely purchase compensatory wetland mitigation credits as part of that 

permitting process. This would result in negligible impacts to wetlands. There would not be 

any indirect impacts (e.g., changes to surface hydrology) to wetlands because environmental 

protection measures (stream buffer zones, erosion and sediment control, and stream flow 

maintenance) would minimize the chance for indirect effects to downstream wetlands. 

4.7.2 Alternative B – PR02 as Revised

4.7.2.1 Previous Impacts 

For wetlands that would be impacted under activities associated with PR02 as approved in 

2007, Colowyo received a USACE 404 Permit (No. 20071185GB) before those wetlands were 

disturbed. As one of the conditions of that permit, in 2008, Colowyo purchased compensatory 

wetland mitigation credits for the loss of 2.12 acres of wetlands associated with the Project. 

Credits were purchased at a 1.5:1 ratio to enable the creation of 3.18 offsite wetland acres at a 

wetlands banking site in south Routt County. There has not been any indirect impact (e.g., 

changes to surface hydrology) to wetlands. There has not been any impact to riparian areas or 

other WOTUS.

4.7.2.2 Potential Impacts

No additional direct impacts to wetland, riparian, or WOTUS would occur. Environmental 

protection measures associated with the Project (stream buffer zones, erosion and sediment 

control, and stream flow maintenance) would continue to minimize the chance for indirect 

effects to downstream wetlands.

4.7.3 No Action Alternative

The effects to wetlands would be the same as under Alternative B.

4.7.4 Mitigation Measures

Mitigation measures have already occurred for wetlands with the creation of 3.18 acres of offsite 

wetlands through the purchase of mitigation credits. No additional mitigation measures would be

necessary for wetlands. 

4.8 FISH AND WILDLIFE 

4.8.1 Alternative A – Proposed Action, PR02 as Approved in 2007

Short-term impacts to wildlife would occur primarily through gradual loss of habitat and 

disturbance by mining and human presence. These impacts, as described below, would be 

minor to moderate. Areas of habitat that are lost due to mining and related activities within 

the Project Area would be reclaimed as soon as those areas are out of production. At the end 

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of the Project, all habitat would be restored in accordance with the approved reclamation plan, 

which includes goals to replace or improve wildlife habitat. At the end of the Project, 

disturbance to wildlife as a result of noise (Section 4.18) and human activity would cease.

Big Game

Within the Project Area, Alternative A would remove 1,181 acres (17 percent) of mule deer 

summer range, 279 acres (20 percent) of mule deer severe winter range, 1,181 acres of elk 

summer and winter range (17 percent), and 184 acres (15 percent) of elk production (calving) 

area. This would be a minor to moderate, short-term impact on mule deer and elk range until 

reclamation replaced (or improved) these habitats within the Project Area. There would not 

be any impact to pronghorn habitat.

Although big game would tend to displace from areas being disturbed and away from active 

mining activities, based on observations at the existing mining operations within the mine 

boundary, both elk and mule deer have been shown to acclimate to the disturbance from 

mining operations (Colowyo 2011). Herds are commonly found on previously reclaimed areas 

that are adjacent to active mining operations, including during calving season. 

Migratory Birds

Impacts to migratory birds within the Project Area could include destruction of nests and eggs in 

unidentified nests if clearing activities occurred during nesting season and those nests were not found 

and subsequently avoided. Disturbance to suitable habitat may affect nesting opportunities and 

migration and migratory birds would tend to be displaced from active mining areas; however, 

these habitats are available outside the Project Area, and, therefore, this impact would be minor. 

Noise produced by mining operations may also affect migratory birds. Noise can interfere with 

establishment of breeding territories for songbirds that vocalize during breeding, or interfere 

with alarm calls of birds and mammals (Larkin 1996; USDI 2003). These impacts would be 

short-term and minor.

Raptors

Impacts to raptors could result from vehicle strikes and collisions with power lines; these 

impacts would be lessened from the implementation of design features (Section 2.2.3). 

Therefore, the primary impacts that may result to raptors under this alternative would be from 

loss of habitat and disturbance to individuals. Nesting locations and foraging habitat within 

1,181 acres would be removed. Noise and human presence could disturb individuals that 

forage in the area. Nesting raptors are often sensitive to disturbance from human related 

activities. Raptors may often abandon nests with eggs or young increasing the potential for 

mortality from predation or intolerance to high or low temperatures. The amount of 

disturbance that an individual raptor will tolerate varies among species and individuals (CPW 

2003). Impacts to nesting raptors could extend beyond the actual disturbance area up to 0.5 

miles (0.8 km) away (CPW 2003). While 10 nest sites are located within the Project Area, only 

one is located within the disturbance footprint. This nest was last observed to be active in 

1997 and was occupied by a Cooper’s hawk (Accipiter cooperii) (Monarch 2000). Under 

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Alternative A, this nest would be lawfully removed after young had fledged which would be a 

negligible impact.

Reptiles and Amphibians

In addition to the loss of habitat, some mortality could occur from construction, mining 

activities, and vehicle operation. The loss of approximately 2.12 acres of wetlands could impact

amphibian populations using these specific areas; however, compensatory wetland mitigation 

would replace similar habitat offsite.

Fisheries

While there are perennial streams within the Project Area (Wilson Creek), none occur where 

disturbance would take place. Therefore, there would be no direct impacts to fisheries from 

previous disturbance and mining activities. Implementation of design features (Section 2.2.3) 

would reduce the likelihood of sediment or a spill of petroleum products or hazardous 

materials reaching fish-bearing streams. Potential indirect effects to fisheries are provided in 

Section 4.9, specifically to the federally listed Colorado River fish; the nearest habitat for 

Colorado River fish is located in the Yampa River approximately 11 miles (18 km) from the project 

area, and 17 miles (27 km) from proposed surface disturbance. 

4.8.2 Alternative B – PR02 as Revised

4.8.2.1 Previous Impacts

Short-term impacts (Section 4.9.1) to wildlife occurred primarily through the loss of habitat

on 789 acres, including impacts to big game habitat. Previous impacts to big game habitat 

include the removal of approximately 789 acres (11 percent) of mule deer summer range, 66 

acres (5 percent) of mule deer severe winter range, 789 acres (11 percent) of elk summer and 

winter range, and 90 acres (9 percent) of elk production (calving) area.

In addition to habitat loss, some species may have been displaced from the Project Area from 

the increased noise and human activity that has taken place since 2008. Based on observations at 

the existing mining operation, big game have become accustomed to the disturbance and are observed 

adjacent to active mining areas. Design features (Section 2.2.3) have reduced other possible 

direct and indirect impacts to wildlife, such as mortality related to vehicle strikes and effects to 

raptors from power lines; there have not been any reported raptor impacts related to vehicle collisions 

or power lines since 2007. No take of migratory birds has been reported to mine management 

since the initiation of mining in 2008 (T. Tennyson, personal communication, May 29, 2015). 

One raptor nest (Section 4.9.1) was lawfully removed as part of previous mining activities. 

Valuable habitat features such as foraging and cover vegetation have been replaced on 66 acres 

that have been reclaimed to date. 

4.8.2.2 Potential Impacts

Overall, the incremental impacts to wildlife would be negligible under Alternative B. The 

remaining disturbance would impact an additional 20 acres within the Project Area. Impacts to 

wildlife and fish species would be the same as described in Section 4.9.1; however, the 

additional disturbance is unlikely to change these impacts from their current levels (Section 

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4.9.2.1). Design features (Section 2.2.3) would continue to be implemented to reduce the 

impacts to wildlife. Impacts from the cumulative disturbance would be offset by the large 

amount of similar habitat available outside the Project Area. The reclamation and restoration 

of disturbed habitat would be the same as under Alternative A. Additionally, Colowyo would 

implement avian protection measures to avoid, minimize, and mitigate impacts to migratory birds, 

including bald and golden eagles. Measures would include pre-construction nesting surveys, adherence 

to CPW recommended buffer zones and season restrictions for raptors, if feasible, and coordination 

with CPW and USFWS for nests that cannot be avoided. Mitigation measures are further described in 

Section 4.8.4. 

4.8.3 No Action Alternative

Under the No Action Alternative, all mining related activities in the Project Area would cease 

and closure and reclamation would be initiated. There would be no further impacts related to 

habitat loss. The reclamation of wildlife habitat and the cessation of noise and human 

disturbance would occur earlier than under Alternatives A or B. 

4.8.4 Mitigation Measures

To mitigate impacts for future mining related disturbance (grubbing and topsoil removal), Colowyo 

would implement an avian protection plan that outlines mitigation requirements for migratory birds. 

The plan would outline how Colowyo addresses active nests found in future disturbance areas, a 

protocol on nest location, and consultation with the appropriate state authorities. Mitigation measures 

in the avian protection plan would include:

 

• No ground disturbing activities including grubbing and topsoil removal topsoil would occur from 

December 15 to July 15 to avoid the nesting season for migratory birds.

• Prior to commencement of grubbing and topsoil removal (after July 15), a nesting survey would 

be conducted no sooner than 72 hours prior to initiation of operations by a qualified biologist to 

identify active breeding pairs or potential nesting locations. Should the qualified biologist 

identify active nest(s) in the proposed mining disturbance area, ground disturbing activities 

within the CPW recommended buffer zone would not occur and Colowyo would immediately 

contact CPW to coordinate proper mitigation measures.

4.9 SPECIAL STATUS SPECIES

4.9.1 Alternative A – Proposed Action, PR02 as Approved in 2007

Design features (Section 2.2.3) would be implemented to reduce the impact to special status 

species. Areas of habitat that would be lost due to mining and related activities within the 

Project Area would be reclaimed as soon as those areas are out of production. At the end of 

the Project, all special status species habitat would be restored in accordance with the 

approved reclamation plan, which includes goals to replace or improve wildlife habitat. 

Disturbance to special status species as a result of noise and human activity would cease. 

Overall, the impacts to special status species are expected to be negligible under Alternative A. 

Threatened, Endangered, and Candidate Species

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Colorado River Fish

The nearest habitat for the Colorado River fish species is the Yampa River, approximately 11

miles (18 km) from the Project Area (17 miles [27 km] from any proposed disturbance). Due to the 

design features (Section 2.2.3) associated with Alternative A, it is unlikely that these species 

would be impacted by sediment or spills. The perennial stream in the Project Area (Wilson 

Creek) does not contain habitat for these species. 

It is estimated that mining under Alternative A would result in the depletion of 424.5 acre-feet 

per year to the Yampa River. This depletion was anticipated to result in adverse impacts to the 

Colorado River fish species (USFWS 2006). The USFWS Biological Opinion for PR02 (USFWS 

2007, Appendix D) contains the following discussion on impacts to the Colorado River fish 

from water depletions:

A recovery Implementation Program for Endangered Fish Species in the Upper 

Colorado River Basin was initiated on January 22, 1988. The Recovery Program 

was intended to be the reasonable and prudent alternative for individual projects 

to avoid the likelihood of jeopardy to the endangered fishes from impacts of 

depletions to the Upper Colorado River Basin. In order to further define and 

clarify the process in the Recovery Program, a Section 7 agreement was 

implemented on October 15, 1993, by the Recovery Program participants. 

Incorporated into this agreement is a RIPRAP which identifies actions currently 

believed to be required to recover the endangered fishes in the most expeditious 

manner. 

On January 10, 2005, the USFWS issued a final programmatic biological opinion 

(PBO) on the Management Plan for Endangered Fishes in the Yampa River Basin. 

The USFWS has determined that projects that fit under the umbrella of the Yampa 

River PBO would avoid the likelihood of jeopardy and/or adverse modification of 

critical habitat for depletion impacts. The Yampa River PBO states that in order 

for actions to fall under the umbrella of the PBO and rely on the RIPRAP to offset 

its depletion, the following criteria must be met:

1. A Recovery Agreement must be offered and signed prior to conclusion of 

Section 7 consultation.

2. A fee to fund recovery actions will be submitted as described in the Proposed 

Action for new depletion projects greater than 100 acre-feet per year (af/yr).

3. Reinitiation stipulations will be included in all individual consultations under the 

umbrella of this programmatic.

4. The USFWS and project proponent will request that discretionary federal 

control be retained for all consultations under this programmatic.

The Recovery Agreement was finalized by the USFWS and the mine on March 3, 

2007 in conjunction with the previous Section 7 consultation for the mine. As this 

project would deplete more than 100 af/year, recovery fees were collected from 

the mine. OSMRE has previously agreed to condition their approval documents to 

retain jurisdiction should Section 7 consultation be reinitiated. Therefore, the 

USFWS concluded that the Proposed Action [PR02] meets the criteria to rely on the 

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RIPRAP to offset depletion impacts and is not likely to jeopardize the continued existence 

of the species and is not likely to destroy or adversely modify designated critical habitat. 

In addition to impacts from water depletions, the Colorado River fish may be indirectly 

impacted from the combustion of coal at local power generation stations. The nearest of these 

stations is the Craig Generation Station located along the Yampa River in Craig. Combustion 

of coal releases mercury into the atmosphere which may be deposited into habitat for the 

Colorado River fish directly, or onto adjacent land and subsequently washed into the river.

Mercury is a concern primarily to longer-lived fish species (e.g., Colorado pikeminnow) because 

it bioaccumulates within the tissue of individuals. Therefore, the longer an individual lives and 

absorbs mercury, the higher the levels within their tissues over time. Mercury can affect an 

individual’s central nervous system, alter their behaviors (e.g., reduced predator avoidance), and 

disrupt the endocrine system resulting in reduced reproductive success (Lusk 2010). While the 

specific effects of mercury and other heavy metals on pikeminnow are known, the role these 

contaminants play on suppressing populations of the Colorado River fish are not well 

understood (USFWS 2011b).

Beckvar et al. (2005) suggested a threshold-effect level of ≤ 0.2 micrograms per gram (μg/g) wet 

weight mercury in whole body fish as being generally protective of juvenile and adult fish. The USFWS 

reported that 78 percent of the Colorado pikeminnow collected in Colorado had levels of mercury 

above the 0.2 μg/g level, including within the Yampa River Basin (Osmundson and Lusk 2012). 

Samples taken from pikeminnow in the Yampa River in 2006 had levels of mercury between 0.42 and 

0.68 μg/g (CDPHE 2015c). Osmundson and Lusk (2012) found a range of 0.39 to 0.58 μg/g with a 

mean level of 0.48 μg/g in Yampa River pikeminnow. The mercury levels reported above are lower 

than what was reported for pikeminnow that were captured in 1960s from the Yampa River (Lusk 

2010). In that study, archived fish samples from museums were tested using similar methods as the 

pikeminnow captured recently and compared to what was reported by Osmundson and Lusk (2012). 

That information was presented to the San Juan Recovery Program and indicated that fish collected in 

1960 had mercury levels of approximately 0.62 μg/g, approximately 0.10 μg/g higher than current 

levels. It should be noted that due to the limited number of fish in the Yampa River, sample size for 

these studies is generally low (less than 10). Therefore, additional study is needed to be able to make 

an overall statement as to how mercury is currently affecting these species.

In addition to impacts to individual Colorado River fish, impacts would also potentially occur to those 

species designated critical habitats in the region. As with any other listed species with designated 

critical habitat, the critical habitat for the four fish species all contain the primary constituent elements 

(PCEs) that are required to be present and are determined to be necessary for the survival and recovery 

of the species. All four species’ critical habitat contains the following PCEs (50 CFR 13378):

1. Water: This includes a quantity of water of sufficient quality (i.e. temperature, dissolved 

oxygen, lack of contaminants, nutrients, turbidity, etc.) that is delivered to a specific location in 

accordance with a hydrologic regime that is required for the particular life stage for each 

species;

2. Physical Habitat: This includes areas of the Colorado River system that are inhabited or 

potentially habitable by fish for use in spawning, nursery, feeding, and rearing, or corridors 

between these areas. In addition to river channels, these areas also include bottom lands, side 

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channel, secondary channels, oxbows, backwaters, and other areas in the 100-year floodplain, 

which when inundated provide spawning, nursery, feeding and rearing habitats, or access to 

these habitats;

3. Biological Environment. Food supply, predation, and competition are important elements of the 

biological environment and are considered components of this constituent element. Food supply 

is a function of nutrient supply, productivity, and availability to each life stage of the species. 

Predation and competition, although considered normal components of this environment, are 

out of balance due to introduced nonnative fish species in many areas.

Mercury from the combustion of Colowyo coal at the Craig Generating Station that is deposited either 

directly or indirectly into the designated critical habitat for these species would have the potential to 

adversely impact the critical habitat. This would occur primarily by increasing the amount of 

contaminates present in those areas (PCE #1). It is difficult to quantify the level of this impact from 

Alternative A to critical habitats given the lack of information on where the mercury in the analysis area 

originates from. However, if it is assumed that only five percent of the mercury generated at the local

generating stations is deposited into the analysis area (EPRI 2014), the impact directly from Alternative 

A may be minor. However, when added to the other regional and global sources of mercury deposited 

into the area, Alternative A may result in cumulatively adverse impacts. 

Emissions of mercury related to combustion at the Craig Generating Station dropped from 130 lbs/year 

in 2008 to 30 lbs./year in 2009 due to the installation of improved environmental controls at the Craig 

Generating Station; mercury emissions from 2010 to 2013 ranged between 42 and 43 lbs/year 

(Section 4.3). Given the amount of mercury that is present in the coal mined at Colowyo and the 

existing controls at the Craig Generating Station, an average amount of 36 lbs. of mercury would be 

emitted annually from the Station including the Colowyo coal mined under this alternative. While the 

prevailing winds would generally result in the deposition of the emitted mercury east of the Craig 

Generating Station and away from habitat for the Colorado River fish, it is probable that some of the 

mercury would be deposited in the Yampa River and have the potential to indirectly impact these 

species. Given that the current levels of mercury in pikeminnow in the Yampa River are above the 0.2 

ug/g threshold for detrimental effects, these depositions would have an indirect impact on these species. 

Of the amount of mercury annually deposited in the analysis area (as well as the larger Yampa and 

White River Basins), it is reasonable to assume that some portion would deposit directly or indirectly 

into the Yampa or White Rivers or their tributaries. Some of this mercury would be converted into 

methyl mercury and thereby has the potential to adversely affect the Colorado River fish. However, 

because of a lack of data or modelling it is not possible to quantify the amount of mercury that would 

enter the Yampa and White Rivers, or be converted to methyl mercury. Therefore, at this time it is not 

possible to accurately predict the impact to the Colorado River fish or their habitat.

Due to the uncertainties in how mercury is potentially affecting the Colorado River fish species, it is 

difficult to draw a conclusion to impacts from Alternative A as some of the data appears to be 

contradictory. In a recent study, pikeminnow populations in the Yampa River were reported to be 

declining but had low mercury concentrations compared to other river segments (Osmundson and Lusk 

2012). It should be noted that mercury levels in the Yampa River were still above the: human 

consumption advisory level of 0.3 μg/g wet weight set by the EPA; toxicity threshold of 0.2 μg/g wet 

weight (Beckvar et al. 2005); and, the 0.1 μg/g WW for the protection of fish eating birds and 

mammals (Yeardley et al. 1989). Conversely, pikeminnow in the White River had high levels of 

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mercury concentrations but the population was increasing (Osmundson and Lusk 2012). The increase 

in the pikeminnow population in the White River was attributed to upstream movement of juvenile 

pikeminnow that originated in downstream Green River reaches during 2006 and 2007 and not from 

reproduction occurring in the White River itself (Bestgen et al. 2010). Further studies are required to 

determine how mercury is affecting species in the Yampa and White Rivers before a conclusion may be 

drawn between Alternative A and impacts to the Colorado River fish and their critical habitats. 

In addition to mercury, impacts to the Colorado River fish from increases in selenium from the 

combustion of coal at the Craig Generating Station could occur. Selenium, a trace element, is a natural 

component of coal and soils in the area and can be released to the environment by the irrigation of 

selenium-rich soils and the burning of coal in power plants with subsequent emissions to air and 

deposition to land and surface water. Contributions from anthropogenic sources have increased with 

the increases of world population, energy demand, and expansion of irrigated agriculture. Selenium, 

abundant in western soils, enters surface waters through erosion, leaching, and runoff. While required 

in the diet of fish at very low concentrations (0.1 μg/g) (Sharma and Singh 1984), it is unknown if 

selenium is adversely affecting endangered fish in the Yampa Basin. Excess dietary selenium causes 

elevated selenium concentrations to be deposited into developing eggs, particularly the yolk (Buhl and 

Hamilton 2000). If concentrations in the egg are sufficiently high, developing proteins and enzymes 

become dysfunctional or result in oxidative stress, conditions that may lead to embryo mortality, 

deformed embryos, or embryos that may be at higher risk for mortality.

Reporting limits for selenium in water is generally one microgram per liter (μg/L) while the EPA has set 

the maximum contaminant level goal of 0.05 mg/L (50 μg/L) for human consumption. During 

sampling of the Yampa River between 1997 and 1998, levels between less than one and 4.8 μg/L 

were found near Craig, between less than one and 4.9 μg/L near Maybell, and less than one and 3.6 

μg/L near Deerlodge Park (USGS 2001). The peak reported levels for these sites all occurred in 

March, possibly during the beginning of the snow runoff. Concentrations were less than 1 μg/L during 

May through October. However, it should be noted that selenium in water may be less important than 

dietary exposure when determining the potential for chronic effects to a species (USFWS 2014).

Of the four Colorado River fish species, selenium would disproportionately affect the razorback sucker 

more than the other three species. As with all sucker species, the razorback sucker is a bottom feeder 

and more likely to ingest selenium that has precipitated to the river bottoms. 

While the reportable limit of selenium in water is 1 μg/L, the safe level of selenium for protection of fish 

and wildlife in water is considered to be below 2 μg/L and chronically toxic levels are considered to be 

greater than 2.7 μg/L (USFWS 2014). Excess selenium in fish have been shown to have a wide range 

of adverse effects including mortality, reproductive impairment, effects on growth, and developmental 

and teratogenic effects including edema and finfold, craniofacial, and skeletal deformities.

Combustion of coal at the Craig Generating Station could result in some amount of selenium being 

emitted and subsequently deposited. However, as it is not monitored as it is emitted, unlike mercury, 

there is no information as to how much is released. When selenium is present in flue gas, it tends to 

behave much like sulfur and is removed to some extent via SO2 air scrubbers in place and also absorbs 

onto alkaline fly ash that is subsequently removed by a fabric filter baghouse (EPRI 2008). Therefore, 

due to the lack of information available, it is unknown if selenium is impacting Colorado River fish 

species in the Yampa and White Rivers.

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Although formal Section 7 consultation with USFWS was not conducted for Alternative A, 

consultation on the effects of coal combustion and subsequent mercury and selenium deposition 

in the Yampa River Basin was completed for Alternative B (Section 4.9.2.2). In general, impacts 

to the Colorado River Fish from mercury and selenium under Alternative A would be moderate. 

Greater Sage-grouse

The primary impact to GSG in the Project Area would occur from the direct disturbance and 

displacement of GSG individuals, direct loss of habitat, and a potential increase of predation 

from attracting mammalian predators (CGSSC 2008). The use of perch deterrents would limit the 

potential for an increase in avian predation on this species. 

Construction and land disturbance under Alternative A would not disturb any of the PHMA

that occurs within the Project Area (Section 3.9.1.2). However, 710.2 acres of GHMA

habitat would be disturbed (Table 4.9-1)

11. In addition to these direct impacts, recent (postPR02 as Approved in 2007) consultation with CPW, BLM, and USFWS determined that indirect 

impacts would occur out to 900 meters (2,953 feet) from the edge of disturbance (B. Holmes, 

personal communication, June 25, 2014). This distance was determined based on several years 

of monitoring data from the Axial Basin, where the Colowyo Mine is located and GSG occur 

near existing mining. These short-term impacts to GHMA would be minor to moderate until 

successful reclamation occurred. Reclamation would focus on improving GSG habitat, including 

boosting available GSG forage and brood production, in disturbed areas. This would be a longterm benefit to GSG and would lessen the impact to GHMA. 

Impacts to leks are unlikely to occur. The nearest active lek (SG4) to the disturbance footprint 

is approximately 4.5 miles (7.2 km) away and would not likely be impacted by mining activities 

in the Project Area given the distance and the topographic screening between the lek and the 

disturbance footprint. As there is no seasonal habitat for GSG that would be disturbed (Table 

4.9-1) no impacts are anticipated to occur during nesting or brood-rearing periods. 

Table 4.9-1 Disturbance to GSG Habitat, Alternative A

Habitat 

Designation

Acres Directly 

Disturbed

Percent of total 

habitat type

directly 

disturbed

Acres Indirectly 

Disturbed within 

a 900 meter 

buffer1

Total Acres 

Disturbed 

(Direct & 

Indirect)

PHMA 0 0 0 0 

GHMA 710.2 13 2,575.7 3,285.9

Production Area 0 0 0 0

Brooding Habitat 0 0 0 0

Winter Range 0 0 0 0

1. The buffer distance of 900 meters was determined based on telemetry data from marked GSG in the Axial Basin. The data 

show that GSG typically remain this distance from mining operations (B. Holmes, personal communication, June 25, 2014).

11 Note that designations of PHMA and GHMA were not established at the time PR02 was approved in 2007.

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Western Yellow-billed Cuckoo

As there is limited habitat within the Project Area for western yellow-billed cuckoos, impacts would be 

limited to those resulting from coal combustion and subsequent mercury emission at the Craig 

Generating Station. For the yellow-billed cuckoo, as with other riparian birds, mercury is accumulated 

through the ingestion of aerial insects emerging from benthic life stages in aquatic environments 

containing mercury or from associated predatory spiders (Cristol et al. 2008; Edmonds et al. 2012; 

Evers et al. 2012; Buckland-Nicks et al. 2014; Gann et al. 2014). Dietary total mercury concentrations 

associated with adverse effects to birds are generally greater than 0.1 mg/kg wet weight (DOI 1998). 

Once ingested, mercury rapidly moves into the bird’s central nervous system, resulting in behavioral and 

neuromotor disorders (Tan et al. 2009; Scheuhammer et al. 2007, 2012). Therefore, adverse effects 

are described for the eggs, embryos, nestlings, and/or fledglings associated with elevated mercury

burdens in the female parent and due to foraging.

No information is available on the levels of mercury in the Yampa River invertebrates within the region. 

However, it could be assumed that given the levels of mercury that currently exist in the Yampa River, 

that the aquatic invertebrates may contain elevated levels of mercury. Any yellow-billed cuckoos present 

in the analysis area would be at risk for mercury contamination. Therefore, Alternative A would have 

the potential to adversely affect this species. However, that risk would be low considering that the 

primary food sources for the cuckoo are generally not aquatic. Given the lack of sightings of this 

species within the analysis area since 2008, it is unknown how many individuals would have the 

potential to be affected. It is difficult to determine the level of impact given there is no threshold 

information for yellow-billed cuckoos as to what may be an acceptable amount of mercury in their 

systems without adverse symptoms. Information is also lacking on current, actual amounts of mercury 

in yellow-billed cuckoos that inhabit the region. Given the low numbers of cuckoos that are thought to 

reside in the area, it would be difficult to obtain this data.

Given that the yellow-billed cuckoo may not return to the same breeding areas in successive years, it is 

possible that if any individuals were impacted by mercury in one year, they may travel to a new location 

in subsequent years that are not impacted by mercury generated from the Craig Generating Station. 

Similarly, as cuckoos are migrants, they would not be present in the analysis area year-round, further 

reducing the potential for mercury contamination.

In addition to impacts to individual yellow-billed cuckoos, the proposed critical habitat for this species 

may also be impacted by Alternative A. The USFWS has designated critical habitat for the western 

yellow billed cuckoo along the Yampa River in the analysis area that contain the following PCEs (79 FR 

48554):

1. Riparian woodlands; 

2. Adequate prey base; and,

3. Dynamic riverine processes 

Alternative A may have the potential to impact critical habitat through adverse impacts to the cuckoo’s 

prey base. Different orders of invertebrates often react to mercury differently although in general 

insects in the larval stages are most susceptible to mercury. Levels of 1 to 10 μg/L normally cause 

acute toxicity for the most sensitive developmental stage of many different species of aquatic 

invertebrates (Boening 2000). 

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As stated above, Alternative A would result in some level of mercury deposition in the analysis areas. 

Some of this mercury may affect the invertebrates that make up the cuckoo’s prey base, thereby 

affecting the proposed critical habitat (PCE #2). It should be noted, however, that aquatic insects and 

amphibians are not the primary food source for cuckoos. It is not known how much of the mercury 

deposited would be generated from Colowyo coal burned at the Craig Generating Station. Therefore, it 

is not possible to determine the severity of this impact to the proposed critical habitat. 

Mercury is not anticipated to affect the cottonwoods or other riparian vegetation that comprises the 

majority of habitat for this species as wood plants are generally insensitive to the harmful effects of 

mercury (Boening 2000).

Overall, Alternative A would have minor impacts to the western yellow-billed cuckoo.

State Listed and BLM Sensitive Species

Great Basin Spadefoot

The primary impact to this species would occur from a loss of 952 acres of habitat. In addition 

to lost habitat, direct mortality could occur from Project activities e.g., vehicle strikes and earth 

moving. There is a large amount of suitable habitat for this species outside of the Project Area; 

therefore, Alternative A would result in minor short-term impacts until successful reclamation, 

when reclamation goals would prioritize the replacement of wildlife habitat.

Ferruginous Hawk

Impacts to ferruginous hawks from Alternative A would occur primarily through a loss of 1,181

acres of foraging habitat. While there are no known nest sites within or near the Project Area, 

mining activities have the potential to prevent ferruginous hawks from nesting in the area. This 

species is known to be sensitive to human disturbance up to approximately 0.5 mile (0.8 km) 

(CPW 2003). There is a large amount of suitable and undisturbed foraging habitat for this 

species outside of the Project Area; therefore, Alternative A would result in minor short-term 

impacts until successful reclamation, when reclamation goals would prioritize the replacement 

of wildlife habitat.

Mountain Plover

Impacts to the mountain plover would occur primarily through a loss of 10 acres of potentially 

suitable habitat. However, mountain plovers are known to be tolerant of human activities and 

use disturbed areas for breeding and foraging (CPW 2003). This would be a negligible impact 

on this species.

Bald Eagle

Mining within the Project Area would disturb 1,181 acres of foraging habitat for bald eagles. 

This is not likely to affect the carrying capacity for bald eagles in the region given the large 

amount of similar habitat that remains in the vicinity of the Project Area. However, mining may 

displace big game, small mammals, and other food sources in some areas, which may impact the 

bald eagle’s ability to feed in and near the Project Area. Bald eagles may also be displaced from 

the Project Area due to noise and an increase in human presence; however, bald eagles have been 

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observed using the area adjacent to the mine haul road. Design features (Section 2.2.3) would be

employed that reduce the potential for impacts to eagles from power lines. Activities under 

Alternative A would be likely to affect individual bald eagles through loss of foraging habitat, but are not 

likely to adversely affect nesting or roosting individuals and pairs given the lack of presence in the 

Project Area. Therefore, the impact to bald eagles would be minor to moderate until successful 

reclamation, when reclamation goals would prioritize the replacement of wildlife habitat.

Columbian Sharp-tailed Grouse

Impacts to the Columbian sharp-tailed grouse in the Project Area would occur primarily 

through the loss of 1,181 acres of habitat. Of the mapped habitat within the area, Alternative A 

would remove 216.8 acres of mapped winter habitat. This is approximately 6 percent of the 

mapped winter habitat within the Project Area. This species is considered to have a moderate 

tolerance for human disturbance (Hoffman and Thomas 2007),), and they have been observed 

using reclaimed mining lands at the mine (T. Tennyson, personal communication, September 15, 

2014). This would be a minor, short-term impact to mapped winter habitat until successful 

reclamation. The reclamation strategy of targeting GSG brood rearing habitat would also benefit 

Columbian sharp-tailed grouse forage and brood production. There are no leks within 2 

kilometers of the disturbance area; therefore, there would not be any impacts on brood 

production. 

Burrowing Owl

Impacts to burrowing owls would occur primarily through a loss of 958 acres of habitat that 

may contain holes for burrowing owls. Design features (Section 2.2.3) would be employed that 

reduce the potential for impacts related to power lines. There is a large amount of suitable 

undisturbed habitat for this species outside of the Project Area; therefore, Alternative A would 

result in minor short-term impacts until successful reclamation, when reclamation goals would 

prioritize the replacement of wildlife habitat.

American Peregrine Falcon

Impacts to peregrine falcons would occur primarily through a loss of 1,181 acres of foraging 

habitat. There is a large amount of suitable foraging habitat for this species outside of the 

Project Area; therefore, Alternative A would result in minor short-term impacts until successful 

reclamation, when reclamation goals would prioritize the replacement of wildlife habitat. As 

this species nests in cliffs and bluffs overlooking waterbodies, there would not be a loss of 

nesting habitat because these areas do not occur in or near the Project Area.

Brewer’s Sparrow

Impacts to the Brewer’s sparrow would occur primarily through a loss of 953 acres of 

shrubland habitat. In addition to loss of habitat, any individuals nesting in the disturbance area

could potentially suffer mortality if unknown active nests were inadvertently impacted. There is 

a large amount of suitable undisturbed habitat for this species outside of the Project Area; 

therefore, Alternative A would result in minor short-term impacts until successful reclamation, 

when reclamation goals would prioritize the replacement of wildlife habitat.

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Townsend’s Big-eared Bat

Impacts to the Townsend’s big-eared bat would occur from a loss of 1,181 acres of foraging 

habitat. Direct impacts would be minimized through design features (Section 2.2.3). Because

mining activities occur 24-hours a day, mortality from vehicle or facility collisions could occur 

when bats forage on insects attracted to the lights used during night-time operations. There is 

a large amount of suitable undisturbed foraging habitat for this species outside of the Project 

Area; therefore, Alternative A would result in minor short-term impacts until successful 

reclamation, when reclamation goals would prioritize the replacement of wildlife habitat. 

White-tailed Prairie Dog

Impacts to white-tailed prairie dogs would occur primarily through a loss of 1,181 acres of 

habitat. In addition to lost habitat, individual white-tailed prairie dogs within the disturbance 

footprint may be killed during surface disturbing activities. There is a large amount of suitable 

undisturbed habitat for this species outside of the Project Area; therefore, Alternative A would 

result in minor short-term impacts until successful reclamation, when reclamation goals would 

prioritize the replacement of wildlife habitat.

4.9.2 Alternative B – PR02 as Revised

4.9.2.1 Previous Impacts

Threatened, Endangered, and Candidate Species

Colorado River Fish

The nearest habitat for the Colorado River fish species is the Yampa River, approximately 11

miles (18 km) from the Project Area (17 miles [27 km] from any proposed disturbance). Due to the 

design features (Section 2.2.3) in place, it is unlikely that these species have been impacted by 

sediment or spills. Mining activities conducted since 2008 have met the criteria to rely on the 

RIPRAP to offset depletion impacts to Colorado River fish, and thus are not likely to have 

jeopardized the continued existence of these species, and are not likely to have destroyed or 

adversely modified designated critical habitat (USFWS 2006). 

Impacts from mercury and selenium would be similar to those described under Alternative A. However, 

as less coal would be mined under Alternative B, there would be less mercury and selenium emitted 

from combustion at the Craig Generating Station so impacts would be less associated with Colowyo 

coal. Given the lack of information for these species, Colowyo has committed to conducting studies on 

mercury (Section 4.9.4). In a Biological Opinion prepared by the USFWS (Appendix D), the 

USFWS determined that Alternative B would likely adversely impact these species and their critical 

habitat, but would not jeopardize their continued existence. Therefore, impacts to Colorado River fish 

from Alternative B would be moderate.

Greater Sage-Grouse 

The primary impact to GSG from the Project has occurred from the direct disturbance and 

displacement of GSG individuals, direct loss of habitat, and a potential increase of predation 

from attracting mammalian predators (CGSSC 2008). Perch deterrents would limit the potential for 

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avian predation on this species. Construction and land disturbance since 2007 has not disturbed 

any of the PHMA that occurs within the Project Area (Section 3.9.1.2). However, 665.9 

acres of GHMA habitat has been directly disturbed and 2,144.6 acres have been indirectly 

disturbed (Table 4.9-2). 

There are no mapped leks present, therefore impacts to leks are unlikely to have occurred. As 

there is no seasonal habitat for GSG that has been disturbed (Table 4.9-2), no impacts are 

anticipated to have occurred during nesting or brood-rearing periods. 

Table 4.9-2 Previous Disturbance to GSG Habitat

Habitat 

Designation

Acres Directly 

Disturbed

Percent of total 

habitat type 

directly 

disturbed in the 

Project Area

Acres Indirectly 

Disturbed within 

a 900 meter 

buffer1

Total Acres 

Disturbed 

(Direct & 

Indirect)

Preliminary Priority 

Habitat 0.0 0.0 0.0 0.0

Preliminary General 

Habitat 665.9 13.9 2,144.6 2,810.5

Production Area 0.0 0.0 0.0 0.0

Brooding Habitat 0.0 0.0 0.0 0.0

Winter Range 0.0 0.0 0.0 0.0

1. The buffer distance of 900 meters was determined based on telemetry data from marked GSG in the Axial Basin. The data 

show that GSG typically remain this distance from mining operations (B. Holmes, personal communication,, June 25, 2014).

Western Yellow-billed Cuckoo

Impacts from previous actions under Alternative B would be similar to those described for Alternative A. 

As there is little riparian habitat, no direct impacts would have occurred. The 2015 BO for this project 

concurred with the finding that there would be no adverse impacts to this species from Alternative B 

(Appendix D). Indirect impacts from mercury deposition from the Craig Generating Station are similar 

to Alternative A. However, as there is less coal combusted under Alternative B compared to Alternative 

A, the impacts would be lessened.

State Listed and BLM Sensitive Species

For all of the impacts described below (except mountain plover), Alternative B would result in 

minor short-term impacts until successful reclamation, when reclamation goals would prioritize 

the replacement of wildlife habitat. 

Great Basin Spadefoot

The primary impact to this species has occurred from a loss of 569 acres of potentially suitable 

habitat; reclamation has replaced 66 acres of this disturbance. In addition to lost habitat, direct 

mortality may have occurred from Project activities e.g., vehicle strikes and earth moving. 

Ferruginous Hawk

Impacts to ferruginous hawks from Alternative B have occurred primarily through a loss of 789 

acres of foraging habitat; reclamation has replaced 66 acres of this disturbance. While there are 

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no known nest sites within or near the Project Area, mining activities have had the potential to 

prevent ferruginous hawks from nesting in the area. Mitigation measures included as part of 

Colowyo’s avian protection plan (Section 4.8.4), such as pre-construction surveys and nest buffers, 

would minimize any direct impacts to nests.

Mountain Plover

Impacts to the mountain plover have occurred primarily through a loss of 13 acres of 

potentially suitable habitat. This would be a negligible impact on mountain plover. Preconstruction surveys would be conducted prior to any future ground disturbing activities to ensure there 

are no impacts to breeding plovers in the Project Area.

Bald Eagle

Activities since 2007 are likely to have affected bald eagles but are not likely to have adversely 

affected the species (USFWS 2006). Mining within the Project Area has disturbed 789 acres of 

foraging habitat for bald eagles; reclamation has replaced 66 acres of this disturbance. The 

impacts to bald eagle are similar to those under Alternative A although lessor in area. There 

are no known incidences of bald eagle mortality within the Project Area. Design features 

(Section 2.2.3) have been employed that reduced the potential for impacts to eagles related to 

power lines. Additionally, Colowyo would implement mitigation measures as outlined in the avian 

protection plan in Section 4.8.4 to address potential impacts to eagles during future disturbance.

Columbian Sharp-tailed Grouse

Impacts to the Columbian sharp-tailed grouse in the Project Area have occurred primarily 

through the loss of 786 acres of habitat; reclamation has replaced 66 acres of this disturbance. 

Approximately 253 acres (7 percent) of the habitat lost is mapped winter habitat. 

Burrowing Owl

Impacts to burrowing owls have occurred primarily through a loss of 600 acres of habitat that 

may contain holes for burrowing owls; reclamation has replaced 66 acres of this disturbance. 

Design features (Section 2.2.3) have been employed that reduced the potential for impacts 

related to power lines. 

American Peregrine Falcon

Impacts to peregrine falcons have occurred primarily through a loss of 789 acres of foraging 

habitat; reclamation has replaced 66 acres of this disturbance. As this species nests in cliffs and 

bluffs overlooking waterbodies, there has not been a loss of nesting habitat as these areas do 

not occur in or near the Project Area. 

Brewer’s Sparrow

Impacts to the Brewer’s sparrow have occurred primarily through a loss of 569 acres of 

shrubland habitat; reclamation has replaced a portion of this disturbed habitat. In order to avoid 

inadvertently impacting nests, Colowyo would conduct pre-construction clearance surveys in suitable 

habitat. If nests are identified, Colowyo would implement its avian protection plan. 

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Townsend’s Big-eared Bat

Impacts to the Townsend’s big-eared bat have occurred from a loss of 789 acres of foraging 

habitat; reclamation has replaced 66 acres of this disturbance. Implementation of design features 

(Section 2.2.3) that limit vehicle speeds have helped to minimize impacts to this species; however, the 

effects of mining operations on bat populations is unknown. Because mining activities occur 24-

hours a day, mortality from vehicle or facility collisions may have occurred when bats foraged 

on insects attracted to the lights used during night-time operations.

White-tailed Prairie Dog

Impacts to white-tailed prairie dogs have occurred primarily through a loss of 789 acres of 

habitat; reclamation has replaced 66 acres of this disturbance. In addition to lost habitat, 

individual white-tailed prairie dogs within the disturbance footprint may have been killed during 

surface disturbing activities. 

4.9.2.2 Potential Impacts 

Approximately 20 additional acres of land would be disturbed during the remaining life of the 

mine. These 20 acres occur primarily in the mountain shrub community. Therefore, the 

additional habitat lost would only affect those species that may occur in this habitat type. 

Impacts to special status species would be the same as described in Sections 4.9.1 and 4.9.2.1

only less so because of less additional disturbed acreage. However, the additional disturbance 

under Alternative B is unlikely to change any impacts from their current levels due to the 

limited amount of additional acres involved. Design features (Section 2.2.3) would continue 

to be implemented to reduce the impact to special status species and avian mitigation measures 

(Section 4.8.4) would minimize impacts to migratory birds. Impacts from the cumulative 

disturbance would be offset by the large amount of similar undisturbed habitat available outside 

the Project Area as well as a reclamation plan that would restore disturbed areas back to 

wildlife habitat. Overall, the incremental impacts to special status species would be negligible 

under Alternative B. The reclamation and restoration of disturbed habitat would be the similar 

to that under Alternative A.

Formal Section 7 consultation on the effects of coal combustion and subsequent mercury and 

selenium deposition on the Colorado River fish and western yellow-billed cuckoo in the Yampa River 

basin under Alternative B is complete. The final determination for the remaining potential impacts to 

the species is “Likely to Adversely Affect” but “not likely to jeopardize” the four Colorado River fish 

species, and “not Likely to Adversely Affect” the yellow-billed cuckoo. The potential impacts under 

Alternative B are the same as described above in Section 4.9.2.1. As part of the consultation process 

with USFWS, several conservation measures were committed to and are described below in Section 

4.9.4. 

4.9.3 No Action Alternative

Under the No Action Alternative, all mining related activities in the Project Area would cease 

and closure and reclamation would be initiated. The impacts to special status species would be 

the same as under Alternatives A and B, but the reclamation of special status species habitat 

and the cessation of noise and human disturbance would occur earlier.

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4.9.4 Mitigation Measures

Mitigation measures for special status species and migratory birds are outlined in Section 4.8.4. 

Mitigation measures were developed during the preparation of the biological assessment associated 

with this project. Those measures would provide direct and indirect benefits to the Colorado River fish 

and western yellow-billed cuckoo.

4.9.4.1 Colorado River Fish

Due to the uncertainty of understanding where the mercury that is being deposited into the Yampa and 

White River basins originates, Colowyo and Tri-State have committed to funding a study to further 

develop the knowledge of source attribution for future decision making. The overall goal of this effort is 

to improve the amount of information available to researchers and policy makers regarding mercury in 

the Yampa and White River basins.

The Electric Research Policy Institute (ERPI) would conduct an air quality deposition modeling analysis to 

determine the sources of mercury being deposited in the Yampa and White River basins. Mercury is a 

global pollutant and may undergo atmospheric transport over both short and very long 

(intercontinental) distances depending on its chemical form. The attribution of sources contributing to 

mercury deposition in the Yampa and White River basins would be determined from modeling 

conducted at multiple geographic scales: global, regional and local. A global mercury model, GEOSChem, would be applied to provide concentrations of mercury in the U.S. due to distant sources. The 

Community Multi-scale Air Quality model and the Community Multi-scale Air Quality - Advanced Plume 

Treatment model would be used to simulate emissions and deposition at a finer scale. At the local level 

individual sources would be modeled to determine their contribution to loading in the analysis area. The 

atmospheric models keep track of which sources or source categories contribute to eventual deposition 

by “tagging” or labeling each unit of mercury by where it originated. Tags are carried along with the 

calculations for deposition so that the analysis of deposited mercury into the local analysis area can 

show how much and from which sources. Deposition receptors would be identified in the local scale 

modeling. For comparison, in the modeling EPRI did in the Four Corners region (the San Juan River 

Basin project), the local scale power plants contributed 2 percent or less of the atmospheric mercury 

deposition (EPRI 2014). The deposition modeling and source attribution analysis for the Yampa and 

White River basins would be conducted similar to the deposition modeling and source attribution 

analysis performed for the San Juan River Basin Project. The analysis would consider anthropogenic and 

natural sources of mercury deposition and would model the transport, chemical transformation and 

deposition of mercury under both wet and dry conditions. 

Information gathered from this modeling effort would fill an obvious gap in the information available for 

the protection of the Colorado River fish species. Results of the study would also be used as part of the 

adaptive management process.

Colowyo would also contribute $50,000 to the National Fish & Wildlife Foundation who would then 

distribute the money to the Endangered Fish Recovery Program’s Upper Colorado River Fish Recovery 

Program. This measure would directly benefit the Colorado River fish species in the two rivers impacted 

by mining and combustion of coal mined at the Colowyo Mine. The funds are to be directed toward the 

control of nonnative fish species in both the Yampa and White River’s designated critical habitat for the 

Colorado Pike Minnow, or to support other recovery activities that directly benefit the endangered fish 

such as habitat improvement. 

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4.9.4.2 Yellow-billed Cuckoo

While critical habitat has been proposed for the western yellow-billed cuckoo, there is a lack of specific 

information as to how much of the proposed critical habitat represents actual, high quality 

breeding/nesting habitat and how much represents foraging habitat for the cuckoo. Colowyo would

fund an effort to delineate which portions of the proposed critical habitat along the Yampa River 

contain the key habitat suitability components for the cuckoo. Colowyo would have a habitat mapping 

methodology developed and implemented in coordination with the USFWS. The relevant scientific 

literature would be reviewed to determine the vegetation component, distance to water, and patch size 

requirements for the western yellow-billed cuckoo. Data to be used in this effort would come from 

existing data sets already developed and available. These include aerial imagery, Southwest Regional 

Gap Analysis habitat data, The Nature Conservatory and CPW habitat suitability data, and any other 

currently available agency data. A ground-truth effort on publically accessible land would be conducted 

to facilitate the assessment of vertical integration of the mid-story vegetation layers that are difficult to 

detect remotely. The final product of this effort would include reporting on established methods, results, 

and GIS mapping of the proposed critical habitat into areas of “good,” “moderate,” and “unsuitable” 

habitat classifications. 

4.10 CULTURAL AND HISTORIC RESOURCES

The APE for cultural resources is the Project Area. This includes all associated mine-related 

facilities including the overburden stockpiles, access roads, power lines, water lines, sediment 

pond, diversion ditches, etc., and the haul road to the load out facility. 

NRHP-eligible (i.e., historic properties) and cultural resource sites that require additional 

testing to determine eligibility (“needs data”) may be directly or indirectly impacted by surface 

disturbing activities or the construction of associated infrastructure. “Needs data” sites are 

managed as though they are eligible for the NRHP until further evaluated. Indirect impacts may 

include increased soil erosion and gullying, vibration from blasting, and dust from operations. In 

addition, there would be increased potential for unlawful artifact collection and/or vandalism of 

cultural resources. Other indirect impacts may include degradation of the site setting, thereby 

detracting from the viewshed and historic feeling of nearby cultural resource sites.

There are no NRHP-eligible cultural resource sites within the APE; however, three “needs 

data” sites are present within the APE (Table 4.10-1). 

Table 4.10-1 NRHP-Eligible and “Needs Data” Cultural Resource Sites within APE

Site 

Number Site Type Cultural Affiliation NRHP Evaluation Within area of proposed disturbance?

5MF1652 Open camp Prehistoric Needs Data No - Outside

5MF4003 Open camp Prehistoric Needs Data No - Outside

5MF4010 Lithic scatter Prehistoric Needs Data No - Outside

4.10.1 Alternative A – Proposed Action, PR02 as Approved in 2007

Of the three “needs data” sites within the APE, none would be directly impacted by Alternative 

A. 

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“Needs data” sites that are outside the proposed disturbance areas but within the permitted 

mine boundary would be avoided. For the sites that occur outside the area of proposed 

disturbance, there would be no adverse effect from the undertaking as proposed. If any of 

these sites cannot be avoided, a testing program would be initiated to determine their NRHP 

eligibility.

4.10.2 Alternative B – PR02 as Revised

4.10.2.1 Previous Impacts

The APE was inventoried (TRC Mariah 2006) for cultural resources prior to PR02 as Approved 

in 2007 (Section 3.11). No NRHP-eligible or “needs data” sites have been impacted by the 

mining activities associated with PR02 as Revised. 

4.10.2.2 Potential Impacts

Of the three “needs data” sites within the APE, none would be directly impacted by Alternative 

B. However, all three are adjacent to existing roads. Any impacts to these sites would 

constitute an adverse effect. 

Sites that are outside the proposed 20-acre additional disturbance area but within the 

permitted mine boundary would continue to be avoided. For the sites that occur outside the 

area of proposed disturbance, there would be no adverse effect from the undertaking as 

currently proposed. If any of these sites cannot be avoided, a testing program would be 

initiated to determine their NRHP eligibility.

In accordance with 36 CFR 800.3 and NHPA Section 106, a letter was mailed on June 17, 2015 

(Appendix E) seeking consultation with the SHPO, tribes, and other interested parties, 

notifying them of the undertaking, and requesting comments or concerns. Tribal consultation is 

presented in Section 4.12. A June 3, 2015 response (Appendix E) stated that SHPO “does 

not have additional concerns at this time for the South Taylor Permit Area.” With 

implementation of the Cultural Resource Protection stipulations, there would be no adverse 

effect to NRHP-eligible or “needs data” cultural resources.

4.10.3 No Action Alternative

Under the No Action Alternative, mining would cease and closure and reclamation would be 

initiated. No additional disturbance beyond the existing disturbance footprint would occur. 

Therefore, there would be no impacts to NRHP-eligible or “needs data” cultural resource sites. 

4.10.4 Mitigation Measures

Discoveries

If a previously unidentified cultural resource is discovered in the Project Area, Colowyo would

take measures to protect the cultural resource and provide written notice to the CDRMS and 

the OSMRE within 48 hours. A Colorado-permitted archaeologist meeting the Secretary of the 

Interior’s Professional Qualifications Standards would, as soon as possible, evaluate the 

discovery, make a recommendation as to NRHP eligibility of the resource, and provide written 

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notice to the CDRMS and the OSMRE within 48 hours. The CDRMS and OSMRE would then

consult with the SHPO and the BLM (for federally managed sites) on NRHP eligibility 

determinations and to develop appropriate measures necessary to mitigate the effects through 

the development of a treatment plan. 

Should the discovery involve a burial or a resource thought to have potential religious and 

cultural significance such as a Traditional Cultural Property, the tribes with an interest would be 

notified and consulted with as appropriate. When agreement is reached between all parties 

involved, the appropriate mitigation measures, if necessary, would be implemented. The tribes, 

OSMRE, CDRMS, SHPO, and the surface landowner must agree to the treatment measures.

Human Remains

If human remains are exposed during mining activities, these activities would be halted at once 

in the vicinity of the discovery. The remains would be covered over and stabilized, and access 

to the immediate area would be blocked by flagging and/or temporary fencing. Operations 

would cease for 100 feet in all directions around the site of discovery.

Unmarked burials located on private or state land would be treated under CRS 24-80-401 and 

CRS 24-80-1301. Colowyo would contact the County Sheriff, the County Coroner, and the 

appropriate land management agency to notify them of the discovery. The Coroner would

investigate the discovery within 48 hours and may enlist the assistance of a physical 

anthropologist, archaeologist, or other specialist to determine if the remains are of forensic 

interest. If the remains are not of forensic interest, the Coroner would contact the Office of 

the State Archaeologist (OSAC) at History Colorado. OSAC would then contact the land

management agency and the Colorado Commission of Indian Affairs (CCIA) to formulate a 

treatment plan within 10 days of the discovery. OSAC and CCIA would coordinate Native 

American Tribal notifications and subsequent consultations. Colowyo would comply with the 

directives of OSAC and CCIA with respect to archaeological treatment of the remains. 

For unmarked burials identified on federally managed lands, the requirements of the Native 

American Graves Protection and Repatriation Act (NAGPRA) would apply in accordance with 

43 CFR 10.

4.11 INDIAN CONCERNS 

4.11.1 Alternative A – Proposed Action, PR02 as Approved in 2007

Various tribes and tribal organizations were contacted in 2007 regarding Alternative A

(Appendix E). No concerns were raised regarding any specific religious site, sacred site, or 

traditional cultural property. No impacts to Indian concerns have been identified related to 

Alternative A. 

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4.11.2 Alternative B – PR02 as Revised

4.11.2.1 Previous Impacts

No impacts to Indian concerns were identified related to the mining activities associated with 

PR02 since 2007. 

4.11.2.2 Potential Impacts

Scoping letters describing the Project were sent to the Eastern Shoshone Tribal Council, Ute 

Mountain Ute Tribal Council, Ute Indian Tribe Tribal Council, and the Southern Ute Tribal 

Council on May 21, 2015. An additional consultation letter was sent to the tribes on June 17, 

2015 noting the SHPO’s current status of no new concerns and requesting any specific 

concerns they may have regarding the Project under the NHPA (Appendix E). To date, none 

of the tribes responded that the proposed project would have an impact on their tribal 

concerns. 

4.11.3 No Action Alternative

Under the No Action Alternative, mining would cease and closure and reclamation would be 

initiated. No additional disturbance beyond the existing disturbance footprint would occur. 

Therefore, there would be no impacts to Indian concerns.

4.11.4 Mitigation Measures

No mitigation measures would be necessary for Indian concerns as no Indian concerns have 

been identified. 

4.12 SOCIOECONOMICS

4.12.1 Alternative A – Proposed Action, PR02 as Approved in 2007

Under Alternative A, mining would occur at a rate of 5.8 to 6.0 mtpy. At this production rate, 

55 to 105 more personnel than are currently employed at the mine would need to be hired and 

additional equipment operated. Annual payroll, insurance, and retirement contributions; local 

expenditures; taxes; and royalty payments would increase from those currently provided by 

Colowyo (Section 3.12). For the relatively small communities near the Project Area, the 

sources of revenue directly related to the mining operation at Colowyo represent a large 

portion of the revenue coming into the area. Indirectly, secondary businesses such as grocery 

stores, retail shops, restaurants, and hotels benefit from these sources of revenue to 

employees. The Craig Generating Station, which burns Colowyo coal, has an indirect effect on the 

socioeconomics of the area by also contributing wages, insurance, taxes, retail spending, housing 

requirements, etc. 

These effects would be moderate to major, short-term, beneficial impacts on socioeconomics. 

These increased economic contributions to the Project Area would extend to 2017, when the 

mine is estimated to cease operations under Alternative A. After closure begins, there would 

be approximately 18 employees remaining to conduct closure and reclamation, but the 

economic contribution directly or indirectly related to the Project Area would be much less

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than during active mining operations. The area has become relatively dependent on the 

economic contribution of the mine, so the loss of this portion of the economy would be acute

and adverse unless Colowyo expands to an area outside the Project Area. Further, the area’s 

demand and expansion of housing, social services, schools, and businesses have largely been 

driven by the development of the mine since 1977. Once all active mining operations both 

inside and outside the Project Area have ceased, this same level of services would not be 

needed, leaving an excess of housing and likely cuts to social services such as police, fire, and 

health care.

Once all active Colowyo mining operations have ceased, the State of Colorado would not 

collect severance taxes from Colowyo ($1,285,287 in 2014) (negligible impact). Federal coal 

lease royalty payments would not be collected from Colowyo ($9.5 million per year on average 

2010-2014) and 49 percent of those funds would not be dispersed to the State of Colorado and 

the affected counties ($4.77 million per year on average) (negligible impact on Colorado, minor 

to moderate long-term impact on the affected counties). 

4.12.2 Alternative B – PR02 as Revised

4.12.2.1 Previous Impacts

The mine has been operating within the Project Area since 2008, and has been affecting the 

socioeconomics of Moffat, Rio Blanco, and Routt counties since that time and since the mine’s 

first development in 1977. A small increase in the number of employees (294 to 316, 7.5 %) 

occurred between 2006 and 2009 after the previous approval of PR02; however, the number of 

employees has since decreased to 220 in 2014 (T. Tennyson, personal communication, July 10, 

2015). The economic contributions of the mine extend beyond these counties when secondary 

businesses such as equipment manufacturers and suppliers are included.

4.12.2.2 Potential Impacts

Under Alternative B, mining is anticipated to continue with approximately the same number of 

personnel (220), the same mining rate, and the same equipment as is currently being used for 

the existing mining operation on the Project Area. No additional demand for housing or 

municipal services would be anticipated. Mining operations would be extended throughout the 

life of the Project; therefore, the current socioeconomic conditions would extend to 2019. 

The extension of mining operations would extend the annual payroll, insurance, and retirement 

contributions ($29 million per year); local expenditures; taxes ($1.4 million per year); and 

royalty payments ($4.77 million per year) to the affected counties which would be $70 million 

more than the life of the mine under Alternative A. This would be a moderate short-term 

impact. After closure begins, there would be approximately 18 employees remaining to 

conduct closure and reclamation, but the economic contribution of the Project Area would be 

much less. The closure of the mine on the area’s housing, services, and economy would be the 

same as under Alternative A but it would likely occur at least two years later. The State of 

Colorado would receive less severance taxes per year under Alternative B due to the lower 

production rate and lower tonnage mined, but those severance tax payments would be 

received for two years longer than under Alternative B. This impact would be negligible.

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4.12.3 No Action Alternative

Under the No Action alternative, mining would cease and closure activities would begin in the 

Project Area. There would be an immediate and substantial decrease in economic 

contributions to the analysis area, if no additional mine expansions are permitted and approved. 

Approximately 200 direct jobs and associated payroll, insurance, and retirement contributions

would be lost if no additional mining takes place. The housing market and school enrollment in 

Craig and Meeker would decline as many of the current Colowyo employees would need to 

leave the area to find job opportunities elsewhere. This would also reduce the amount of local 

expenditures by mine employees and their families and taxes in these communities that would 

create further job losses to secondary businesses. 

Under the No Action alternative there would be no additional mining, thus no additional 

severance taxes paid to the State of Colorado, and no royalties paid to the federal, state, and 

local governments. This would lead to decreased funding to local governments for 

infrastructure maintenance and development. By closing two years (Alternative A) or four 

years (Alternative B) earlier under the No Action alternative, socioeconomic changes would 

occur earlier and the economic loss to the local community would be at least $70 million when 

compared to Alternative A and approximately $140 million when compared to Alternative B, if 

no additional mine expansions are permitted and approved. These would be major, long-term 

impacts to the socioeconomics of the local area and minor impacts to the State of Colorado. 

4.12.4 Mitigation Measures

No mitigation measures would be necessary for socioeconomic resources. 

4.13 VISUAL RESOURCES

Over the course of mining operations in the Project Area, impacts to visual resources would 

occur through observable changes in the topography, color, and texture of the lands in the 

Project Area, and through indirect visibility of mining operations by the presence of dust. Most 

of the disturbance in the Project Area (ground level disturbance and pit disturbance) would not 

be visible to the majority of viewers who are traveling on area roads, either because topography 

surrounding the Project Area blocked views of the Project Area or because the Project Area is 

at a higher elevation than viewers. 

Viewers on State Highway 13 and Moffat County Road 51 south of and parallel to the Project 

Area would not be able to see mining disturbance because the highways follow drainages and 

are lower in elevation than the Project Area; topography blocks views of the mine. Similarly, 

because viewers on the highways are in an enclosed landscape, dust from the mining operation 

may not be visible or noticeable.

4.13.1 Alternative A – Proposed Action, PR02 as Approved in 2007

Views from State Highway 13 and Moffat County roads 17 and 32 north of the Project Area are 

open and panoramic; however, intervening topography blocks views of most of the ground level 

disturbance in the Project Area, so mining and reclamation are not visible to viewers in these 

locations. Because the views north of the Project Area tend to be more open and panoramic, 

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dust rising from the mining operation or reclamation may be noticeable and attract the 

attention of viewers traveling on these roads. 

As a result of mining in the Project Area, there would be two permanent valley fill areas and 

two temporary spoil piles. The East Taylor permanent valley fill would be constructed to an 

elevation of 8,050 feet amsl. The West Taylor permanent valley fill would be constructed to an 

elevation of 8,400 feet amsl. The East Taylor temporary spoil pile would be constructed east of 

the East Taylor permanent valley fill, to an elevation of 8,300 feet amsl. The West Taylor 

temporary spoil pile would be constructed on top of the East Taylor permanent valley fill to an 

elevation of 8,300 feet amsl. 

The viewshed analyses below were conducted to determine the visibility of the permanent 

valley fills and the temporary spoil piles. One analysis had the general purpose of determining 

visibility using the highest elevation of valley fill (representing the maximum distance from and 

amount of the valley fill that could be seen), and the other for determining visibility using the 

highest elevation of temporary spoil (representing the maximum distance from and amount of 

the spoil that could be seen) for the other.

4.13.1.1 Short-term Visual Impacts

Viewers traveling on Moffat County Road 32 would have brief intermittent views of the 

temporary spoil piles when approaching the intersection with Moffat County Road 51, looking 

south. Viewers traveling on Moffat County Road 17 north and State Highway 13 east of the 

Project Area would have extended but intermittent views of the temporary spoil piles 

constructed to a maximum elevation of 8,300 feet. Views of the temporary spoil piles would be

as part of a panoramic landscape, looking in a southerly direction from distances ranging from 6 

to 12 miles (10 to 19 km) away. Viewers would see the tops of the spoil piles, which may 

appear to have a form, or be of a color or texture that is not consistent with the surrounding 

undisturbed lands, making them noticeable. Dust rising from the mine may attract attention 

when visible. At higher speeds, the amount of time the spoil piles are visible would be extended 

but intermittent. Frequent travelers along these routes may notice changes in the landscape as 

the spoil piles come into view and as they increase in elevation. Transient travelers may find 

the visible disturbance and dust noticeable. Because of the panoramic nature of the views and 

the ability of the landscape to absorb the changes that are of limited scope, the impact to visual 

resources would be minor and would meet Class IV objectives.

4.13.1.2 Reclamation and Permanent Visual Impacts

During the reclamation process, the spoil material in the temporary spoil piles would be used 

to backfill the pit over a several year period. Over that time, the spoil piles would be gradually 

reduced and existing impacts to visual resources from the visibility of the spoil pile would be 

gradually reduced until the temporary spoil piles are no longer visible; however the permanent 

valley fills, constructed to a maximum elevation of 8,400 feet amsl, would remain and be visible 

in the landscape similar to but less than the temporary spoil piles. Frequent travelers on the 

routes that are accustomed to seeing the spoil piles may notice the change in the landscape and 

it may attract attention, as would ongoing dust generated by ground-disturbing activities. 

Permanent views of the valley fills would be brief for travelers on Moffat County Road 32 in the 

vicinity of the junction with Moffat County Road 51, and would be extended but intermittent 

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along State Highway 13 east and Moffat County Road 17 north of the Project Area. Transient 

travelers may find the visible disturbance and dust noticeable. Upon completion of reclamation, 

hunters or recreationists in close proximity to the reclaimed mine would continue to see 

obvious and noticeable disturbance to visual resources, despite the fact that post-mine 

topography would be developed in accordance with the approved reclamation plan and the area 

would be revegetated. However, the overall impact to visual resources would be minor and 

meet Class IV objectives.

4.13.2 Alternative B – PR02 as Revised

4.13.2.1 Previous Impacts

Views from State Highway 13 and Moffat County roads 17 and 32 north of the Project Area are 

more open and panoramic; however, intervening topography blocks views of most of the 

disturbance in the Project Area, so it is not visible to viewers in these locations. Because the 

views north of the Project Area tend to be more open and panoramic, dust rising from the 

mining operation may be noticeable and attract the attention of viewers traveling on these 

roads. 

As a result of mining in the Project Area, there are two permanent valley fills and two 

temporary spoil piles. The West Taylor permanent valley fill is constructed to an elevation of 

7,950 feet amsl. The West Taylor spoil pile is complete and constructed to 8,200 feet amsl in 

elevation. The East Taylor permanent valley fill is constructed to an elevation of 7,990 feet

amsl. The East Taylor spoil pile is slightly lower. 

The visibility of the temporary spoil piles would result in short-term impacts to visual resources 

while the piles are present, and the permanent valley fills would result in long-term impacts to 

visual resources. Visibility was determined using the highest elevation of temporary spoil 

(representing the maximum distance from and amount of spoil that can be seen highest 

elevation of valley fill for one) and the highest elevation for valley fill for the other (representing 

the maximum distance from and amount of the valley fill that can be seen).

4.13.2.2 Temporary Visual Impacts

Viewers traveling on State Highway 13 and Moffat County roads 17 and 32 north of the Project 

Area have brief intermittent views of the temporary spoil piles as a part of a panoramic 

landscape, looking in a southerly direction from a distance ranging from 6 to 12 miles (10 to 19 

km) away. Viewers are seeing the tops of the temporary spoil piles, which may appear to have 

a form or be of a color or texture that is not consistent with the surrounding undisturbed 

lands, which could make them noticeable. Dust rising from the mine may attract attention 

when visible. At higher speeds, the amount of time the temporary spoil piles are visible would 

be limited. Frequent travelers along these routes may have noticed changes in the landscape as 

the temporary spoil piles came into view as they increased in elevation. Transient travelers 

may find the visible disturbance and dust noticeable. Because of the panoramic nature of the 

views and the ability of the landscape to absorb the changes that are of limited scope, the 

impact to visual resources is minimal and would meet Class IV objectives.

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Hunters or other recreationists in close proximity to the mine, while likely few in number, have 

more comprehensive views of the mining disturbance. The mining disturbance from these 

views has changed the topography, land forms, colors and textures in the view; it is obvious and 

commands attention. However, the disturbance would meet Class IV objectives.

4.13.2.3 Potential Impacts

Mining 

Potential impacts to visual resources would include continued visibility of dust and increase in 

height of the East Taylor temporary spoil pile up to the 8,100-foot elevation. Viewers frequently 

traveling on Highway 13 and Moffat County roads 17 and 32 north of the Project Area may 

notice slight changes in the East Taylor temporary spoil pile as it is completed to an elevation of 

8,100 feet amsl, but overall impacts would be the same as the current visual impacts. Transient 

travelers may find the visible disturbance and dust noticeable. The potential visual impacts to 

hunters or other recreationists in close proximity to the mine would be similar to the current 

impacts. Overall impacts to visual resources would continue to meet Class IV objectives.

Reclamation and Permanent Visual Impacts

During the reclamation process, the temporary spoil pile material would be used to backfill the 

pit over a several year period. Over that time, the temporary spoil piles would be gradually 

reduced and existing impacts to visual resources from the visibility of the temporary spoil piles 

would gradually reduce to the point that the remaining valley fill would be visible in the 

landscape but less so than the temporary spoil piles. Frequent travelers on the routes that are 

accustomed to seeing the temporary spoil piles may notice the change in the landscape and it 

may attract attention, as would ongoing dust generated by ground-disturbing activities. 

Transient travelers may find the visible disturbance and dust noticeable. Upon completion of 

reclamation, hunters or recreationists in close proximity to the reclaimed mine would continue 

to see obvious and noticeable disturbance to visual resources, despite the fact that post-mine 

topography would be reduced back to pre-mining landscape elevation and the area would be 

revegetated. However, the overall impact to visual resources would be minimal and meet Class 

IV objectives.

4.13.3 No Action Alternative

Under the No Action Alternative, mining would cease and closure and reclamation would be 

initiated. No additional disturbance beyond the existing disturbance footprint would occur. 

Impacts from reclamation would be the same as described for Alternatives A and B. 

4.13.4 Mitigation Measures

No mitigation measures would be necessary for visual resources. 

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4.14 RECREATION

4.14.1 Alternative A – Proposed Action, PR02 as Approved in 2007

Camping, OHV use, touring, bird watching, hiking, and other recreational pursuits would not be 

allowed on the Project Area due to safety concerns and conflicts with mining operations. 

Under Alternative A, hunting opportunities would decrease due to the increase in new surface 

disturbance of approximately 1,181 acres within the Project Area. However, hunting in these 

areas has already been discontinued for the safety of the employees and recreationists due to 

proximity to mining operations; therefore, this impact would be minor. Additionally, hunting 

success in areas adjacent to the Project Area may decrease in the short term as big game 

animals are displaced. This impact would likely be negligible as big game animals have become 

accustomed to existing mining activities and re-enter areas readily once mining and reclamation 

activities are complete (Colowyo 2011). At the end of the Project, the disturbance area would 

be reclaimed to the approved post-mining topography. Recreation would be allowed on public 

lands within the Project Area, but private land would remain closed to the public. 

4.14.2 Alternative B – PR02 as Revised

4.14.2.1 Previous Impacts

Recreation and hunting access was closed within the Project Area in 2007. However, big game 

animals have likely been displaced into adjacent lands that are available for hunting (Section 

4.8). 

4.14.2.2 Potential Impacts

Under Alternative B, hunting opportunities would decrease slightly due to the increase in 

disturbance of approximately 20 additional acres within the Project Area. These impacts would 

be similar to those described under Alternative A. At the end of the Project, the disturbance 

area would be reclaimed to the approved post-mining topography. Recreation would be 

allowed on public lands within the Project Area, but private land would remain closed to the 

public 

4.14.3 No Action Alternative

Under the No Action Alternative, mining would cease and closure and reclamation would be 

initiated. No additional disturbance beyond the existing disturbance footprint would occur. At 

the end of the Project, the disturbance area would be reclaimed to approved post-mining 

topography. Recreation would be allowed on public lands within the Project Area, but private 

land would remain closed to the public

4.14.4 Mitigation Measures

No mitigation measures would be necessary for recreation. 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 4-97

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4.15 PALEONTOLOGY

4.15.1 Alternative A – Proposed Action, PR02 as Approved in 2007

As the Project Area lies within a PFYC Class 5 zone, there is the potential that the ground 

disturbing activities would adversely affect fossils. If any such fossils of paleontological interest 

are located in the Project Area, ground disturbing and overburden removal activities could 

damage the fossils and the information that could have been gained from them would be lost. 

The significance of this impact would depend upon the significance of the fossil. Alternative A 

could also constitute a beneficial impact to paleontological resources by increasing the chances 

for discovery of scientifically significant fossils. No significant or unique paleontological 

resources have been recorded within the Project Area. Surface coal mining and related 

activities could have a permanent impact on paleontological resources beneath the surface, 

assuming such resources are present. Paleontological resources not identified and transported

prior to or during mining operations would be permanently lost.

4.15.2 Alternative B – PR02 as Revised

4.15.2.1 Previous Impacts

No paleontological finds have been encountered in the Project Area during mining operations 

to date (T. Tennyson, personal communication, June 9, 2015). 

4.15.2.2 Potential Impacts

Under Alternative B, an additional 20 acres would be disturbed. The impacts would be similar 

to Alternative A.

4.15.3 No Action Alternative

Under the No Action Alternative, mining would cease and closure and reclamation would be 

initiated. No additional subsurface disturbance beyond the existing disturbance footprint would 

occur. Therefore, there would be no additional impacts to paleontological resources.

4.15.4 Mitigation Measures

If paleontological resources are discovered during mining operations on BLM managed lands, 

mine employees shall immediately notify the BLM and shall not disturb such discovered 

resources until the Field Office Manager issues specific instructions. Within five working days 

after notification, the Field Office Manager shall evaluate any paleontological resources 

discovered and shall determine whether any action may be required to protect or to preserve 

such discoveries.

Should paleontological resources be encountered as a result of the Project, OSMRE or the 

SHPO would be consulted as appropriate.

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 4-98

Mining Plan Modification Environmental Assessment
Chapter 4 – Environmental Consequences

4.16 ACCESS AND TRANSPORTATION

4.16.1 Alternative A – Proposed Action, PR02 as Approved in 2007

Existing haul road “A” (3.7 mile [6.0 km] roadway from pit area to Gossard Loadout) and haul 

road “B” (1.4 mile [2.3 km] roadway from State Highway 13 to haul road “A”) would continue 

to be used as part of the South Taylor/Lower Wilson mining area. Access to the South Taylor 

mining area would be through the existing mining area, and, therefore, additional haul roads 

would not be required to be constructed.

Roads that would be constructed in the actual mining areas would constantly change as the 

operation progresses. The “in-pit” roads would be maintained by a motor grader and regularly 

wetted to minimize dust as required by the air quality permit. 

Under Alternative A, there would be a minor, short-term increase in mine truck and employee 

traffic due to an increase in the production rate from an average of 4.5 mtpy to 5.8 or 6.0 mtpy. 

If the rate of production increases, the number of trains per year required to transport coal 

would also increase. 

Colowyo would maintain the haul roads throughout the life of the mine with repairs including 

blading, filling of potholes, and replacement of road surface as necessary. The existing twotrack Sturgeon Road would be upgraded to allow access for construction and for routine 

monitoring and maintenance. Other than the Sturgeon Access Road, there would be no 

changes to existing access roads for the South Taylor pit expansion. Following all mining 

activities, the road would remain in place as a private ranch road and would not be reclaimed.

4.16.2 Alternative B – PR02 as Revised

4.16.2.1 Previous Impacts

Truck haul and access routes were constructed within the Project Area as discussed in 

Alternative A, with one access road connecting to the mine support facilities (roadway from pit 

area to Gossard Loadout); this is where the employee parking lot is located. 

4.16.2.2 Potential Impacts

No new access roads or haul roads would be constructed. No haul trucks would travel on 

public roadways outside of the mine permit boundary. Only mine pickup trucks/utility vehicles

and workers’ personal vehicles would travel on public roads. All coal is removed from the 

mine via trains.

Under Alternative B, if the current mining production rate of 2.48 mtpy would continue, and no 

additional personnel would be employed by the Colowyo Mine, workers at the currently active 

South Taylor Pit would continue until the pit is mined out. As there is no anticipated increase 

in personnel or vehicles used, the overall amount of traffic both within the mine boundary and 

on public roads outside the mine boundary would remain the same as current levels. No 

additional impacts to public roads are, therefore, anticipated. 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 4-99

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Mine use of public roadways as discussed above would occur primarily when shifts change at 

the mine.

4.16.3 No Action Alternative

Under the No Action Alternative, mining would cease and closure and reclamation would be 

initiated. This would result in lower traffic along the public roads leading to the mine and 

decreased impacts to public safety and road maintenance.

4.16.4 Mitigation Measures

No mitigation measures would be necessary for access and transportation. 

4.17 SOLID OR HAZARDOUS WASTE

4.17.1 Alternative A – Proposed Action, PR02 as Approved in 2007

Under Alternative A, impacts to the environment from the potential release of hazardous or 

solid waste are not anticipated to occur. Solid or hazardous waste that may be used or created 

during the coal mining process would be limited to petroleum products (gasoline and diesel 

fuel, oil, lubricants) and ANFO used for blasting. CCRs, generated as a part of the coal 

combustion process, are discussed in Sections 3.5.2 and 4.5.1. 

The potential for impacts from substances released depend on the responsible use of chemicals; 

a SPCC plan (Colowyo 2012b) is in place at the mine to ensure immediate containment and 

adequate cleanup in the event of an unintentional release. The potential for exposure to 

petroleum products, or hazardous or solid wastes would be low but would last for the 

remainder of the life of the mine. Spill kits would be located onsite which would be used in the 

case of accidental releases to assist in rapid clean up. Additionally, appropriate secondary 

containment would be used for all hazardous chemicals storage. No additional chemicals would 

be used under Alternative A that are not already being used at the current mining operation.

Construction sites and all facilities would be maintained in a sanitary condition at all times. 

Regulated waste materials would be disposed of promptly at an appropriate off-site waste 

disposal facility, including all discarded matter including, but not limited to, trash, garbage, refuse, 

oil drums, petroleum products, ashes, and equipment. Colowyo would, as permitted under CDRMS 

Rule 4.11.4, dispose of non-coal wastes onsite. Colowyo would dispose of general house hold-type trash 

in a solid waste facility. Human waste water would be disposed of through a leach field and/or aeration

ponds.

As part of closure/reclamation, all petroleum products not necessary for closure or reclamation 

activities would be removed from the Project Area. Facility structures, including but not 

limited to concrete foundations, would be demolished in-place and covered with a minimum of 

six feet of suitable material. The area would be regraded to blend with the surrounding 

topography followed by topsoil and seeding as described in the reclamation plan. All demolition 

materials (e.g., culverts, fencing) related to sedimentation ponds would be placed within the 

ponds and covered with a minimum of six feet of suitable material or transported to the pit 

area during the reclamation process. Noncoal, nonhazardous solid waste is regulated under the 

Moffat County Special Use permit.

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4.17.2 Alternative B – PR02 as Revised

4.17.2.1 Previous Impacts

There are no previous direct impacts on the Project Area related to solid or hazardous waste. 

CCRs are discussed in Sections 3.5.2 and 4.5.2.1. 

4.17.2.2 Potential Impacts

The direct impacts related to solid and hazardous waste in future mining and reclamation 

operations would be the same as under Alternative A. CCRs are discussed in Sections 3.5.2 

and 4.5.2.2. 

4.17.3 No Action Alternative

Under the No Action Alternative, mining operations would cease. The reclamation operations 

would be the same as those described under Alternative A. CCRs are discussed in Sections 

3.5.2 and 4.5.3. 

4.17.4 Mitigation Measures

No mitigation measures would be necessary for solid or hazardous waste. 

4.18 NOISE

4.18.1 Alternative A – Proposed Action, PR02 as Approved in 2007

Under Alternative A, there would be a minor, short-term increase in noise from blasting 

activities, crushing, and vehicles due to an increase in the production rate from an average of 

4.5 mtpy to 5.8 or 6.0 mtpy. This noise would occur 24 hours a day, 7 days a week. If the rate 

of production increases, the number of trains per year required to transport coal would 

increase. The increase in the number of trains would increase the duration of noise produced 

along the rail line. The noise levels would continue to be below MSHA noise regulations of 

instantaneous exposure level of 115 dBA or an 8 hour TWA of 85 dBA. Once closure begins 

in 2017, the noise levels would decrease but noise from reclamation activities (grading, 

reseeding, demolition of facilities, trucks, etc.) would continue until reclamation was completed.

While no homes occur within the Project Area, several homes are located just outside the 

boundary. The nearest homes occur approximately one to three miles (1.6 to 4.8 km) from 

the Project Area to the south and southeast. Given the topography and vegetation between 

the Project Area and these homes, it is likely that most noise would attenuate before reaching 

these residences.

4.18.2 Alternative B – PR02 as Revised

4.18.2.1 Previous Impacts

The Project Area has been affected directly by the noise from active mining operations 

(blasting, coal loading/conveyance, crushing, and vehicles) in the Project Area since 2008, and to 

a lesser extent from the Colowyo mining on adjacent land prior to 2008.

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4.18.2.2 Potential Impacts

Under Alternative B, the noise currently experienced at the Project Area would continue at the 

same levels, but for two years longer than that under Alternative A. Similar to those under 

Alternative A, the noise levels would continue to be below MSHA noise regulations of 

instantaneous exposure level of 115 dBA or an 8 hour TWA of 85 dBA.

4.18.3 No Action Alternative

Under the No Action Alternative, mining in the Project Area would cease and closure and 

reclamation activities would begin. The level of noise would continue at closure/reclamation 

levels until reclamation was complete. This would occur two or four years sooner under the 

No Action Alternative than under Alternative A or B, respectively. 

4.18.4 Mitigation Measures

No mitigation measures would be necessary for noise. 

4.19 LIVESTOCK GRAZING

4.19.1 Alternative A – Proposed Action, PR02 as Approved in 2007

Under Alternative A, Colowyo would no longer sublease the grazing rights within the Project 

Area to prevent conflicts between the mining operations and livestock grazing. Therefore, 0.6 

to 65 percent of the AUMs in the allotments would be unavailable for grazing in the short term 

(Table 4.19-1). At the end of the life of the mine and when reclamation is successful and 

complete, grazing would be reinstated. Prior to any reintroduction of grazing to the area, final 

bond release of the disturbed area would be required. Post-reclamation grazing would be 

sustained at 60 percent of the carrying capacity to encourage the continued success of 

reclaimed vegetation. The allotments would carry <1 to 39 percent of their original grazing

authorization (Table 4.19-1) post-reclamation. This would be a negligible to moderate, shortterm impact on the availability for livestock grazing on these allotments.

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Table 4.19-1 Impacts to Grazing Allotments, Alternative A

Allotment

Total 

AUMs1 

# of 

AUMs 

Reduced

AUMs 

Remaining

Percent 

AUM 

Reduction

Postreclamation

AUMs1 

% of 

Allotment 

AUMs

Available 

PostReclamation

Taylor 

Creek 170/43 111/28 59/15 65 67/17 39

East Fork 

Wilson 

Creek

170/43 63/16 107/27 37 38/10 22

SmithCrawford 1,219/0 9/0 1,210/0 0.7 5/0 0.4

Colowyo 

Commons 347/173 2/1 345/172 0.6 1/0 0.3

Lower 

Taylor 

Creek

27/0 3/0 24/0 11 2/0 7 

Totals 1,933/259 188/45 1,745/214 113/27 1 Data are shown as number of cattle/sheep. 

4.19.2 Alternative B – PR02 as Revised

4.19.2.1 Previous Impacts

Grazing was removed from the Project Area in 2007. The changes to available grazing were 

the same as identified for Alternative A (Table 4.19-1).

4.19.2.2 Potential Impacts

Under Alternative B, the entire Project Area would continue to be closed to grazing until it was 

reinstated after final bond release of the disturbed area. The impacts on livestock and grazing 

would be the same as those under Alternative A, but grazing would be reinstated 2 years later 

than under Alternative A.

4.19.3 No Action Alternative

Under the No Action Alternative, Colowyo would cease the mining operations and closure 

activities would begin. Grazing would be reinstated after final bond release of the disturbed 

area. The same effects to livestock grazing would occur as under Alternatives A and B, but 

resumption of grazing would occur sooner. 

4.19.4 Mitigation Measures

No mitigation measures would be necessary for livestock. 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 4-103

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4.20 SOILS 

4.20.1 Alternative A – Proposed Action, PR02 as Approved in 2007

Direct short-term impacts to soils would occur on approximately 1,181 acres (Table 4.20-1). 

Topsoil would be removed from the mining area, stockpiled, and used for future reclamation needs 

within the Project Area in accordance with federal and state regulations and the CDRMS permit. Areas 

where topsoil would be removed include the pit, overburden stockpiles, temporary piles, a 

previously reclaimed area, and various small, dispersed features such as access roads and 

sediment ponds. Limiting factors of Project Area soils influencing reclamation suitability 

included certain soils that are shallow and stony, or have subsurface soils that are heavy clays 

with a hard columnar structure and sticky, plastic properties (Colowyo 2012a). The topsoil 

that would be removed would include all of the A and B horizon material, excluding these 

heavy clay soils. The more desirable horizons with loam and clay loam textures would provide 

sufficient volumes (Colowyo 2012a).

Additionally, spoil material would also be monitored to ensure its compatibility and 

appropriateness for use as a sublayer between reclaimed surfaces prior to topsoil replacement. 

As described in Volume 1 - Section 2.05.3 of Permit No. C-1981-019 (Colowyo 2012a), spoil 

material would be sampled at a density of one composite surface sample per five acres of 

regraded spoil, and analyzed for pH, electrical conductivity, and sodium adsorption ratio. The 

results would dictate whether or not topsoil can be placed directly on the spoil material or 

whether additional material needs to be added first.

There would be impacts to soil resources including erosion and fertility losses as a result of 

mining and reclamation activities, due to the disturbance of horizons and the process of 

stockpiling. However, the measures (Table 2.2-2, Appendix B) used in stockpiling and 

maintaining the stockpiles would reduce erosion and fertility loss, so the amount and quality of 

stockpiled soils are expected to be sufficient for reclamation. Salvaged topsoil would be

stockpiled for later use in reclamation. Stockpiled topsoil would be placed on stable sites and 

protected from compaction, wind and water erosion, and contaminants. Topsoil stockpiles 

would also be seeded to minimize erosion. The availability of suitable topsoil and erosion 

control are important factors in the overall reclamation success. Topsoil removal and 

stockpiling may reduce attributes for plant growth such as soil microbial activity, organic matter 

content, fertility, and water holding capacity. 

As feasible, direct haul of removed topsoil to areas ready to be reclaimed would be used 

instead of stockpiling, where there is opportunity to do so. This method, while still disturbing 

the horizons, tends to preserve more of the active biologic processes and also reduces the 

timeframe wherein compaction can occur, and thus results in fewer potential impacts. 

Additionally, this method reduces the potential for erosion losses as soil is not stockpiled.

During reclamation, topsoil would be redistributed in a manner that would maximize its ability 

to provide a viable seedbed. Colowyo has prepared a Topsoil Redistribution Plan (Appendix 

B) that outlines the steps to ensure this.

There would be the potential for impacts to soils from accidental spills or leaks of petroleum 

products and hazardous materials used during construction, mining activities, and long-term 

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operation of the mine, but if they occurred, they would be contained, controlled, and 

remediated as per the spill containment plan (Appendix B). As per the reclamation plan and 

the PAP for PR02 as Approved in 2007 (Colowyo 2007), acid-forming waste is not an issue at 

the mine. Further, Colowyo does not plan to use spoil material for topsoil substitutes or to 

supplement topsoil.

Table 4.20-1 Disturbance to Soil Types, Alternative A

Soil Unit Disturbed

Acres

Campspass fine sandy loam, 12 to 25 percent slopes 15.0

Cochetopa loam, 12 to 25 percent slopes 29.9

Cochetopa loam, 25 to 65 percent slopes 37.0

Jerry-Cochetopa complex, 5 to 35 percent slopes 199.1 

Lamphier-Jerry complex, 25 to 65 percent slopes 26.2

Owen Creek-Jerry-Burnette loams, 5 to 35 percent slopes 577.35

Rhone-Northwater-Lamphier loams, 3 to 50 percent slopes 99.73 

Torriorthents-Rock outcrop complex, 15 to 90 percent slopes 3.38

Ustorthents, frigid-Borolls complex, 25 to 75 percent slopes 134.0

Waybe-Vandamore variant-Rock outcrop complex, 5 to 30 percent slopes 61.6

Total 1,186

Overall, these impacts would be negligible. The potential of each soil for use in reclamation 

would essentially retain the same as its current potential. Colowyo (2012a) has determined 

that it is quite possible that the overall productivity of the area to be mined could be increased. 

In part, this is attributed to the fact that during the topsoil removal process, the smaller 

amounts of poorer soils would become mixed with good soils, and currently unproductive 

areas may become more productive.

4.20.2 Alternative B – PR02 as Revised

4.20.2.1 Previous Impacts

Direct impacts to soils have occurred on approximately 789 acres (Table 4.20-2). Topsoil has 

been removed from the mining area and used to rehabilitate existing disturbed sites outside the 

Project Area, or stockpiled for future reclamation needs in accordance with federal and state 

regulations. Areas where topsoil has been removed include the pit, spoil stockpiles, and 

various small, dispersed features such as access roads and sediment ponds. Approximately 66 

acres has been backfilled, graded, and topsoiled under reclamation; 54 acres of this has also 

been seeded for revegetation.

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Table 4.20-2 Disturbance to Soil Types in the Project Area, Alternative B

Soil Unit

Previous 

Impacts

(Acres)

Potential 

Impacts

(Acres)

Campspass fine sandy loam, 12 to 25 percent slopes 20.82 0

Cochetopa loam, 12 to 25 percent slopes 60.07 0

Cochetopa loam, 25 to 65 percent slopes 25.37 0

Jerry-Cochetopa complex, 5 to 35 percent slopes 133.58 4.31 

Lamphier-Jerry complex, 25 to 65 percent slopes 26.16 0

Owen Creek-Jerry-Burnette loams, 5 to 35 percent slopes 242.53 6.05 

Rhone-Northwater-Lamphier loams, 3 to 50 percent slopes 97.81 1.69 

Torriorthents-Rock outcrop complex, 15 to 90 percent slopes 1.42 0

Ustorthents, frigid-Borolls complex, 25 to 75 percent slopes 153.91 7.85 

Waybe-Vandamore variant-Rock outcrop complex, 5 to 30 percent slopes 27.92 0 

Total 789.59 19.90

There have been impacts to soil resources including erosion and fertility losses as a result of 

mining and reclamation activities, due to the disturbance of horizons and the process of 

stockpiling. However, the measures (Appendix B) used in stockpiling and maintaining the 

stockpiles have reduced erosion and fertility loss, so the amount and quality of stockpiled soils 

are expected to be sufficient for reclamation. Salvaged topsoil has been stockpiled for later use 

in reclamation. Stockpiled topsoil has been placed on stable sites and protected from 

compaction, wind and water erosion, and contaminants. Topsoil stockpiles have also been

seeded to minimize erosion. The availability of suitable topsoil and erosion control are 

important factors in the overall reclamation success. Topsoil removal and stockpiling may 

reduce attributes for plant growth such as soil microbial activity, organic matter content, 

fertility, and water holding capacity. 

There have not been any impacts to soils from accidental spills or leaks of petroleum products 

and hazardous materials used during construction, mining activities, and long-term operation of 

the mine.

4.20.2.2 Potential Impacts

Negligible, short-term direct impacts resulting from the future additional soil salvage would 

occur on approximately 20 acres. Should accidental spills or leaks of petroleum products and 

hazardous materials used during construction, mining activities, and long-term operation of the 

mine occur, they would be contained, controlled and remediated as per the spill containment 

plan (Appendix B). Reclamation and soil stockpiling would occur in the same manner as 

previous. Colowyo does not plan to use spoil material for topsoil substitutes or to supplement 

topsoil.

4.20.3 No Action Alternative

Under the No Action alternative, no additional new ground disturbing activities would take 

place and impacts would be the same as described under Section 4.20.2.1. Reclamation 

would proceed and topsoil would be redistributed on previously disturbed ground. 

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4.20.4 Mitigation Measures

No mitigation measures would be necessary for soils.

4.21 ALLUVIAL VALLEY FLOORS

4.21.1 Alternative A – Proposed Action, PR02 as Approved in 2007

There would not be any impacts to AVFs under Alternative A. There would be no direct 

encroachment in any AVF under Alternative A because none are within the area to be mined 

(Section 3.21 and Figure 3-5). Further, continuing use of stream buffer zones (as identified 

along Wilson Creek, Good Spring Creek, and Taylor Creek) and sediment ponds (Figure 3-5) 

would ensure that Alternative A would not be likely to indirectly affect the character of AVFs 

within or near the Project Area because the hydrologic balance would be maintained and water 

quality would be protected (Section 3.21). In part, as described in Appendix B, stream 

buffer zones would be properly signed, and no stream buffer zones would be encroached upon 

without CDRMS approval. Further, sediment ponds would serve to protect water quality of 

stream flow passing through the downstream AVFs. Water monitoring programs, including 

those designed to document any increased salinity in Good Spring Creek as a result of the 

movement of leached salts from fill material to shallow alluvium, would be used to verify that 

worst case salt loading predictions (CDRMS 2007) are not exceeded. 

Although the Project Area includes Wilson Creek, no Alternative A activities that would have 

the potential to affect that stream’s AVF have been proposed. CDRMS (2007) stipulated that 

should any lands along Wilson Creek be planned for disturbance, prior to approvals Colowyo 

would be required to analyze in detail the Wilson Creek AVF and prepare a detailed 

restoration plan. 

CDRMS (2007) considered the lack of direct impacts and the potential for indirect impacts 

when assessing Alternative A. They found that: 1) the activities would not interrupt, 

discontinue, or preclude farming on the AVFs; 2) that the activities would not materially damage 

the quality or quantity of associated groundwater or surface water systems; 3) operations 

would be conducted to preserve the essential hydrologic functions of AVFs in and downstream 

of the Project Area; and 4) all requirements of CDRMS regulations would be complied with 

throughout operations and reclamation. 

4.21.2 Alternative B – PR02 as Revised

4.21.2.1 Previous Impacts

Although AVFs exist in the Project Area (Section 3.21 and Figure 3-5), they have not been 

directly impacted by mining activities under PR02 as Revised, based upon an analysis of the 

disturbed area. Further, as per Colowyo (2007) and CDRMS (2007) no disturbance of Project 

Area AVFs has been approved. Further, mining has not indirectly affected the character of 

AVFs within or near the Project Area because the hydrologic balance has been maintained and 

water quality has not been materially impacted (Section 4.5.2.1). Essentially, the same 

conditions and conclusions regarding AVFs that are applicable to Alternative A are applicable to 

Alternative B.

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4.21.2.2 Potential Impacts

There would not be any impacts to AVFs under Alternative B. Continuing use of stream buffer 

zones and sediment ponds would ensure that the remaining operations of the Project would

not be likely to indirectly affect the character of AVFs within or near the Project Area because 

the hydrologic balance would be maintained and water quality would be protected. Water 

monitoring programs, including those designed to document any increased salinity in Good 

Spring Creek as a result of the movement of leached salts from fill material to shallow alluvium, 

would continue to verify that worst case salt loading predictions are not exceeded. The 

reclamation plan would be implemented so material damage to AVFs would be avoided.

4.21.3 No Action Alternative

There would not be any impacts to AVFs. Under mine closure, permit obligations such as 

water monitoring, runoff management, and sediment control would remain. 

4.21.4 Mitigation Measures

No mitigation measures would be necessary for AVFs. 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 4-108

Mining Plan Modification Environmental Assessment
Chapter 5 – Cumulative Impacts

CHAPTER 5 CUMULATIVE IMPACTS

5.1 INTRODUCTION

Cumulative impacts are those impacts that result from incremental effects of an action when 

added to other past, present, and reasonably foreseeable future actions regardless of what 

agency or other entity undertakes such other actions.

For most resources, the cumulative impact analysis only examines the two action alternatives 

(Alternatives A and B) because, for the most part, the impacts under the No Action Alternative 

would not differ from the action alternatives but would happen sooner. Also, the No Action 

Alternative in this analysis would not represent incremental impacts that can be compared to 

other past, present, and reasonably foreseeable actions. The two exceptions, Air and Climate 

Resources and Socioeconomics, are evaluated in this chapter because the No Action 

Alternative would be associated with incremental impacts that are unique to the action 

alternatives.

5.2 PAST AND PRESENT ACTIONS

Past and present actions in the general area include coal mining, power generation, ranching, 

recreation, and oil and gas development.

Past coal mining in the area began in 1908 with the underground Collom Mine (later renamed 

the Mount Streeter Mine). Underground coal mining occurred continuously in the area until 

1974 when that mine closed. In 1977, Colowyo initiated its first surface mining operations at 

the Colowyo Coal Mine. Mining in the West Pit ceased in 2014 and the Section 16 Pit was 

active until 2013, but with very limited production. Active mining is currently occurring only at 

the South Taylor Pit. In 2014, the Colowyo Mine produced approximately 2.48 mt of coal

Mines.findthedata.com 2015) and employed 220 people. Currently there are approximately 

4,750 acres of past and present mining disturbance associated with the Colowyo Mine, and 

Colowyo owns approximately 75,570 acres of land in this area. The nearest active coal mine to 

the Project Area is the Trapper Mine, located approximately 16 miles (26 km) to the northeast. 

In 2014, the Trapper Mine produced approximately 2.3 mt of coal (Tri-State 2015b) and 

employed 190 people (Mines.findthedata.com 2015). Other active coal mines in the vicinity 

include, two underground mines, the Foidel Creek Mine (also known as the Twentymile Mine) 

(Routt County), the Sage Creek Mine (Routt County), and the Deserado Mine (Rio Blanco 

County). Other active mining operations within 20 miles (32 km) of the Colowyo Mine include 

seven gravel pits, 22 sand and gravel operations, one limestone operation, and one sandstone 

pit (CDRMS 2014). In addition to these resources, there has been past uranium, oil shale, and 

dimension stone mining operations in the vicinity of the Project Area. Mining has the potential 

to affect many resources through increased disturbance, both on the surface and subsurface. 

Mining also increases the number of people in the area.

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 5-1 

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There are two power plants in the general vicinity of the Project Area: the Craig Generating 

Station and the Hayden Generating Station. The Craig Generating Station, located southwest 

of Craig, is operated by Tri-State; approximately 300 people work at the 1,303-megawatt plant

(Tri-State 2015b). Plant construction began in 1974 with the first operating unit completed in 

1979. The plant site covers 1,120 acres. Its main water source is the Yampa River with 

supplemental allocations from nearby reservoirs. Craig Generating Station receives its coal 

supply primarily from two sources: Trapper Mine, located one mile (1.6 km) south of the plant 

and the Colowyo Mine sited about 30 miles (48.3 km) southwest of the station. Trapper Mine 

delivers coal to the plant via 100-ton haul trucks from the mine site. Colowyo Mine delivers 

coal to the Craig Generating Station daily by train. The station also augments these two 

sources of coal with spot coal purchases from other mines in northwestern Colorado.

The Hayden Generating Station, located four miles (6.4 km) east of Hayden (Routt County), is a 

446 megawatt plant owned and operated by Xcel Energy. Construction began in 1962 with 

operation of Unit 1 in 1965 and a second unit in 1976 (Xcel Energy 2015). The Hayden 

Generating Station receives its coal from the Peabody Coal’s Twentymile Mine and occasionally

the Colowyo Mine (CDPHE 2015b). Coal is delivered to the station via train (Newcomer and 

Pierce 2013). 

Historically, the Project Area and the vicinity have been used for livestock ranching, in 

particular cattle and sheep. Grazing within the Project Area occurs on both private and public 

lands outside of mining areas. Livestock ranching can impact water resources, wetlands, and 

vegetation and may potentially create competition for resources with big game species. 

Colowyo and various other land owners manage privately owned livestock ranches and also 

hold BLM grazing preferences on federal lands throughout the area. For example, the Morgan 

Creek Ranch runs cattle and sheep and includes approximately 30,265 acres, with 25,156 acres 

of Colowyo deeded land and 5,109 acres of BLM land. 

There is limited agricultural land in the vicinity of the Project Area. Colowyo manages 68.5 

acres of wheat fields (dry-land crop) located in the extreme northeast corner of the Project 

Area next to the coal loadout and railroad loop. Areas of irrigated agricultural lands are 

located just east and northeast of the Project Area and Highway 13. Dry and irrigated 

agricultural activities can contribute to air pollution through generation of dust and also may 

impact water sources. 

In addition to ranching, the area also supports wildlife including big game species. Hunting is the 

primary recreational activity in the area. Adjacent to the Project, on Colowyo private land holdings, 

employees are allowed to hunt. No hunting is allowed in active mining areas or within the Project Area. 

Outside of the Colowyo owned lands, hunting and other recreational activities are open to the 

general public on public lands or with the approval of private land owners. No developed 

recreation sites exist in the vicinity of the Project Area. Dispersed recreation generally has few 

impacts outside of an increased amount of noise and people to an area. Other existing 

developments in the vicinity of the Project Area include Highway 13 located immediately east of 

the mine and running from the northeast to the southwest along the eastern permit boundary. 

This is the main highway connecting Craig with Meeker and Rifle. Moffat County Road 51, a 

gravel road, traverses the Project Area from northeast to southwest roughly along the western

boundary of the Project Area. In addition, Moffat County Road 32, also a gravel road, traverses 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 5-2 

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Chapter 5 – Cumulative Impacts

roughly east to west along the northern portion of the Project Area. Various unmaintained dirt 

roads and two tracks also crisscross the Project Area and vicinity. Use of roads increases noise 

impacts due to traffic, as well as increasing dust impacts through use of gravel and dirt roads. 

Vehicles also present a danger to wildlife through wildlife/vehicle collisions although the sparse 

use of the county and smaller roads in the area would have very low mortality on wildlife. 

Highway 13, which is a paved high speed road, would contribute to higher levels of wildlife 

mortality.

The Colowyo railroad spur connects the Colowyo loadout located at the northeast corner of 

the Project Area to the northeast with the Union Pacific main line in Craig. Use of the spur for 

regular coal train traffic results in dispersed impacts on air quality from diesel engine emissions 

and limited impacts from coal dust. In addition, electric transmission lines of various capacities 

traverse the vicinity. Transmission lines pose electrocution hazards to raptors unless designed 

specifically to minimize such impacts. Wilson Reservoir is located approximately 8 miles

(13 km) northeast of the mine along Highway 13. Water storage reservoirs impact 

downstream flows for fisheries and riparian vegetation. 

Oil and gas operations have been occurring in the vicinity of the Project Area since the 1920s. 

To date, within a 20 mile (32 km) radius of the mine there are 755 well locations. Of these, 

552 locations are no longer producing and are abandoned, and 131 locations are producing oil 

or gas. Another 14 wells have been or are in the process of being drilled and completed

(COGCC 2014). Impacts from oil and gas development are similar in nature to those from 

mining, although usually more dispersed over a larger area than for mining operations.

5.3 REASONABLY FORESEEABLE FUTURE ACTIONS

Reasonably foreseeable future actions in the general vicinity of the Project Area include 

additional coal mining, continued ranching and recreational activities, and ongoing oil and gas 

operations.

Given that coal seams exist outside the mine boundary and in the vicinity, it is reasonable to 

assume that coal mining may occur in the future. This may occur either as an extension of 

current mining operations or in new areas. Colowyo submitted a permit application package 

with CDRMS for the Collom Mine (northwest of Project Area), PR03, in 2009 that would 

include two new pits and associated facilities with a total of about 2,090 acres of disturbance. 

CDRMS approved PR03 for the Collom Permit Expansion Area in May 2013. OSMRE is 

currently reviewing the mining plan modification for the Collom Mine project, including 

preparation of a NEPA document. Colowyo proposes to continue to utilize the truck/shovel, 

dragline, and highwall surface mining techniques it has successfully used in other parts of the 

mine since 1977 and is currently using in the South Taylor Pit. In March 2015, Colowyo also 

submitted PR04 to CDRMS which, if approved, would authorize an alternative configuration for 

the mining plan submitted under PR03. That alternative configuration is also being analyzed in 

OSMRE’s NEPA document under preparation. If the Collom mining plan modification is 

approved, it would extend mining operations for the Colowyo mine between about 20 and 40 

years, depending on the mine production rate. Also, if approved, the Collom mining operations 

would have an approximate 3 year overlap with mining at the South Taylor Pit (as proposed 

under Alternative B), as that mining would wind down and the Collom production would 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 5-3 

Mining Plan Modification Environmental Assessment
Chapter 5 – Cumulative Impacts

increase. However, the total mine production rate (combined South Taylor Pit and Collom Pit) 

would remain at about the current 2.5 mtpy during the transition. Produced coal would likely 

be supplied to the Craig power plant as well as other customers throughout the country. BLM 

LSFO is currently processing a federal lease modification application from Colowyo to add 

about 26 acres to a federal lease as part of the Collom proposal. There is no proposed mining 

on the lease modification proposal but the surface would be disturbed for placement of a 

temporary spoil pile. The lease modification is also being analyzed in the Collom NEPA 

document. 

BLM LSFO is also processing a lease modification application from Peabody Energy to add 310 

acres and about 340,000 tons of federal coal to the Foidel Creek Mine. This is an underground 

mine located approximately 45 miles (72 km) southeast of Craig. The mine produces from a 

mix of private, state and federal coal resources and in 2014 produced 7.1 million tons. If 

approved, the mine would not start mining this added federal coal until about 2022. The Foidel 

Creek Mine provides coal to the Hayden power plant, as well as other facilities throughout the 

country, and the coal proposed to be added to the mine production would provide about 78 

days of the power plant’s coal needs. 

CDRMS is currently processing PR07 for the Trapper Mine that, if approved, would add approximately 

775 acres to the permit boundary. PR07 only increases the permit boundary and updates 

the sediment control plan. The Trapper Mine has been permitted by CDRMS, through permit renewal 

six, to continue mining up to 2017 at a production rate of about 2.6 mtpy. 

The Deserado Mine, operated by Blue Mountain Energy Company, is an underground coal mine located 

approximately 50.5 miles (81 km) west of the Colowyo Mine. CDRMS has no pending permit actions 

for this mine. BLM LSFO has no pending lease modifications or lease by applications for this mine.

The Sage Creek Mine, owned by Peabody Energy and operated by Sage Creek Mining, LLC, is another 

underground mine located approximately 38 miles (61 km) northeast of the Colowyo Mine near 

Hayden, CO. Mining began briefly at Sage Creek in May of 2012, but is suspended until market 

conditions improve. While CDRMS considers it to be active, the mine is not producing 

Supplies of coal to the Craig and Hayden power plants from the mines described above are not 

exclusive contracts. The power plants would continue operating even if those mines stopped 

supplying them coal and would purchase coal from other suppliers. No other coal lease 

applications have been filed with BLM in the area, and no SMCRA permit application packages 

have been filed with CDRMS. 

Ranching operations in the area are expected to continue at current levels for the reasonably 

foreseeable future. Additionally, hunting and other recreational activities are also likely to 

continue at current levels into the reasonably foreseeable future.

The BLM’s Colorado State Office conducts quarterly competitive lease sales to sell available oil 

and gas lease parcels. The act of leasing does not authorize any development or use of the 

surface of lease lands, without further application by the lessee and approval by the BLM. Oil 

and gas operations are anticipated to continue in the future in the vicinity of the Project Area; 

however, the exploration and development of new facilities may be limited because much of the 

vicinity is designated GSG habitat. There are currently 24 permitted locations within a 20 mile 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 5-4 

Mining Plan Modification Environmental Assessment
Chapter 5 – Cumulative Impacts

(32 km) radius of the mine (COGCC 2014). In 2014, 112 parcels comprising 86,423.66 acres 

within the LSFO were nominated for the February 2015 Competitive Oil and Gas Lease Sale 

(BLM 2014). In support of this, the BLM LSFO completed an EA for this oil and gas lease sale 

that included parcels in the vicinity of the Project Area. Some of these lease sales may result in 

oil and gas development. After completion of coal mining and reclamation of the current and 

proposed mining areas is completed, oil and gas operations may potentially begin in these areas.

5.4 CUMULATIVE IMPACTS

The following section describes potential cumulative impacts to resources in the vicinity of the 

Project Area from the past, present, and reasonably foreseeable future actions in conjunction 

with Alternatives A and B. Cumulative impacts can result from individually minor but 

collectively significant actions taking place over a period of time (40 CFR 1508.7). The 

cumulative impacts analysis area (CIAA) varies by resource. It may be restricted to the 

immediate Project Area (e.g., for soil impacts) or an entire watershed (e.g., for water 

resources). For the analysis of the cumulative impacts, it is assumed that all design features and 

any applicable mitigation measures would be implemented.

5.4.1 Topography

The CIAA for topography is the Project Area. Additional mining at the South Taylor Pit under 

any of the alternatives would have short-term effects on topography while mining is active until 

successful reclamation is completed. Within the Project Area, a total of 66 acres has been 

reclaimed to date. General pre-mining topography would be approximated through 

implementation of the reclamation plan (Appendix B). In conjunction with other past, 

present, and future activities, cumulative effects on topography would be negligible as these 

other activities generally do not change the overall topographic features of an area and 

reclamation would return the land to the approved post-mining topography. Mining and 

reclamation under the No Action Alternative would conclude sooner than both Alternative A 

and Alternative B. Consequently, cumulative impacts under the No Action are considered less 

than negligible.

5.4.2 Air and Climate Resources

5.4.2.1 Temporal and Geographic Scope

The CIAA for air and climate resources (approximately 4,000 square miles [12,360 km2]) was 

defined using a topographic/airshed approach. An assessment was conducted to determine the 

reasonable airshed where cumulative impacts could occur. Boundaries were defined by 

topographic features. Meeker represents the southwest corner of the airshed. Heading 

northwest along Route 64, the western edge is defined by Sagebrush Draw, Elk Spring Ridge, 

and Cross Mountain. The northwest corner runs through Ninemile Basin just northwest of 

Godiva Rim. The boundary follows the Little Snake River northeast until approximately 

Shaffer’s Draw. The northern boundary extends east across the Great Divide ridge, past 

Highway 13 and the Elkhead Mountains. Sand Mountain represents the northeast corner of the 

air boundary. It heads southeast to the town of Clark. The eastern edge is Steamboat Springs. 

Heading south through the town of Yampa and into Garfield County is the southeastern edge. 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 5-5 

Mining Plan Modification Environmental Assessment
Chapter 5 – Cumulative Impacts

Big Ridge and Oak Ridge back to Meeker encompasses the southern boundary. Figure 5-1

depicts the CIAA for Air and Climate Resources.

5.4.2.2 Surrounding APEN Sources

The CDPHE website provides all criteria pollutant emissions data. All APEN applicable 

(permitted) sources that fall within the airshed boundary were analyzed. There are 128 

sources of VOCs within the airshed boundary, the most of any criteria pollutant. However 

NOx contributes the most emissions at an aggregated total of 19,147 tpy, the majority of which 

originates from the Craig and Hayden Generating Stations. Table 5.4-1 provides the total 

criteria pollutants from APEN sources within the airshed boundary on a tons per year basis. 

Note that as of June 21, 2015 there were no sources of lead reported to CDPHE.

Table 5.4-1 Criteria Pollutant APEN Annual Emissions

Pollutant Total

(tpy)1

PM2.5 837

PM10 3,462

SO2 5,609

NO2 19,147

CO 3,550

VOC 2,798

1. Values are current as of June 21, 2015 

http://www.colorado.gov/airquality/ss_map_wm.aspx 

5.4.2.3 2011 National Emissions Inventory Total Regional Emissions

The 2011 EPA NEI data was used to perform a comparison analysis on all cumulative emission 

impacts related to Alternative A and Alternative B and Table 5.4-2 provides the criteria 

pollutants by county for 2011.

Table 5.4-2 2011 Criteria Pollutants by County (tpy)

1

County CO NOx PM102 PM2.52 SO2 VOC

Garfield 25,325 16,123 4,170 1,210 187 91,075

Moffat 8,188 15,308 5,243 1,351 3,978 5,618

Rio Blanco 6,497 4,810 5,091 1,128 339 26,960

Routt 17,218 7,732 7,856 2,126 2,243 3,758

Total 57,228 43,974 22,359 5,814 6,746 127,411

1. Emissions represent all 14 Tier I Categories as defined by the EPA within the NEI 

database: Fuel Combustion (Electric Utility, Industrial, Other), Chemical & Allied 

Product Manufacturing, Metal Processing, Other Industrial Processes, Solvent 

Utilization, Storage and Transport, Waste Disposal and Recycling, highway 

vehicles, Off Highway Vehicles and miscellaneous sources.

2. Values include both filterable and condensable particulate matter

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 5-6 

Mining Plan Modification Environmental Assessment
Colorado

"d "d

Eagle

Garfield

Eagle

Routt

Garfield

Rio Blanco

Garfield

Routt

Moffat

Rio Blanco

Moffat

Routt

Rio Blanco

Routt

Craig

Generating

Station

Hayden

Generating

Station

Air and Climate Resources CIAA

5-1

Colowyo Coal Mine, South Taylor/Lower Wilson

Permit Expansion Area Mining Plan Modification

Environmental Assessment

Notes

1.

2.

0 8 16

miles

Project Area

Approved SMCRA Permit

Boundary

Cumulative Effects Airshed

Boundary

"d Generating Station

County Boundary

($$ ̄

1:506,880 (At original document size of 11x17)

Disclaimer: Figure prepared for OSMRE by Stantec. Stantec assumes no responsibility for data supplied in electronic format. The recipient accepts full responsibility for verifying the accuracy and completeness of the data. The recipient releases Stantec, its officers, employees, consultants and agents, from any and all claims arising in any way from the content or provision of the data.

Coordinate System: NAD 1983 UTM Zone 13N

Basemap: Content may not reflect National Geographic's

current map policy. Sources: National Geographic, Esri,

DeLorme, HERE, UNEP-WCMC, USGS, NASA, ESA, METI, NRCAN,

GEBCO, NOAA, increment P Corp.

Project 

Location

Project Location

Project

Figure No.

Title

Rio Blanco & Moffat Counties

Colorado

Project Location
Chapter 5 – Cumulative Impacts

5.4.2.4 Cumulative Emissions (Direct and Indirect)

Cumulative emissions for Alternatives A and B were determined using three regional emission 

scenarios. First, the maximum production was implemented to conservatively estimate annual 

criteria pollutants. Second, a regional average of production between the Craig Generating 

Station and the Hayden Generating Station was calculated to represent a typical regional 

emission rate. Last, because the vast majority of coal from the mine is sent to the Craig 

Generating Station, a Craig Only scenario was evaluated. Alternative A shows a high percentage of 

gaseous pollutants, particularly NOx and SO2, when compared to other emission sources within the 

surrounding four counties. However, this is to be expected as the two generating stations contribute the 

vast majority of emissions within the CIAA and the maximum combustion rate is higher than what 

would occur in reality. Alternative B shows a moderate contribution of CO when compared to the 

surrounding counties. For all other pollutants, both alternatives demonstrate a negligible to moderate 

contribution when compared to county, state and national totals. 

Alternative A Cumulative Criteria Pollutant Emissions

The maximum annual mining rate of 6 mtpy generates both direct and indirect emissions 

(Section 4.3). Direct emissions associated with the maximum production rate remains static 

regardless of the regional combustion emission rates (maximum, average, or Craig Only). 

Cumulative criteria pollutant totals are provided in Table 5.4-3 for each combustion rate. 

Average is defined as the mean value between Craig and Hayden Generating Stations. It should 

be noted that 6 mtpy equates to unrealistic combustion rates and the corresponding emissions 

are artificially conservative.

Table 5.4-3 Cumulative Emissions from Criteria Pollutants (tpy)

Activity PM10 PM2.5 NOx CO VOC SO2

Direct Emissions 2,291 267 1,886 11,191. 72 1.3 

Indirect Rail 0.10 0.10 7.0 9.0 0.27 0.03

Indirect Combustion Maximum 508 231 22,197 1,817 168 7,979

Indirect Combustion Average 381 204 20,009 1568 130 6,393

Craig Combustion Only 254 178 17,822 1,817 92 4,807

Total Maximum 2,799 499 24,089 13,017 240 7,980

Total Average 2,672 472 21,902 12,768 202 6,394

Total Craig Only 2,545 446 19,715 13,017 164 4,808

Table 5.4-4 illustrates the percentage of criteria pollutant emissions associated with 

Alternative A relative to the regional totals for the four counties within the CIAA as well as the 

entire state of Colorado. It should be noted that the proposed maximum firing rate of 6 mtpy 

at the Craig Generating Station is unrealistic in practice; hence the percentage comparison is 

greater than 100 percent shown below. 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 5-8 

Mining Plan Modification Environmental Assessment
Chapter 5 – Cumulative Impacts

Table 5.4-4 Criteria Pollutants as Percentage of 2011 Regional Criteria Pollutant 

Emissions

Percentage Comparison CO NOx PM10 PM2.5 SO2 VOC

Proposed Maximum % of 4 Counties 3.2% 50.5% 2.3% 4.0% 118% 0.13%

Proposed Average % of 4 Counties 2.7% 45.5% 1.7% 3.5% 94.8% 0.10%

Proposed Craig Only % of 4 Counties 3.2% 40.5% 1.1% 3.1% 71.3% 0.07%

Proposed Maximum % of Colorado 0.92% 7.9% 0.85% 0.49% 14.3% 0.04%

Proposed Average % of Colorado 0.90% 7.2% 0.81% 0.46% 11.5% 0.04%

Proposed Craig Only % of Colorado 0.92% 6.5% 0.77% 0.44% 8.6% 0.03%

Alternative A Cumulative GHG Emissions

Climate change by nature is a cumulative process; the discussion of direct and indirect 

emissions relative to the current global GHG emissions rates and the projected impacts 

provided above is for all practical purposes the same one that would be provided here, and 

therefore does not bear repeating. However, it is worth noting that sea level rise and ocean 

acidification (while not a regional concern) are a major cumulative concern that the Proposed 

Action would contribute toward, albeit insignificantly.

The values detailed in Table 5.4-5 represent the total GHG emissions impacts from the 

combustion of all coal under Alternative A along with all direct mine-related activities. The 

worst case annual emissions assume that all mined coal (at the 6 mtpy maximum mining rate) is 

combusted in one year. Note that the calculation methodology for railroad engine emissions 

uses only a representative CO2e factor; thus the individual component emissions are already 

calculated within the factor. Also, only methane is emitted from the physical extraction of coal 

and its subsequent handling. 

Table 5.4-5 Cumulative Emissions from Greenhouse Gases (metric tonnes/yr)

Activity CO2 CH4 N2O CO2e

Direct Combustion 237,813 9.28 5.46 239,673

Indirect Rail Combustion -- -- -- 3,284

Methane Release 0 3,326 0 83,149

Indirect Combustion 13,952,822 1,645 239 14,065,277

Total 14,190,635 4,980- -244 14,387,837

Table 5.4-6 compares the potential GHG emissions from 6 million tpy to state-wide totals and 

national totals from the 2011 NEI database and the 2014 Colorado Greenhouse Gas Inventory 

Update. 

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 5-9 

Mining Plan Modification Environmental Assessment
Chapter 5 – Cumulative Impacts

Table 5.4-6 GHG Emissions as Percentage of State and National Emissions 

(mmt/yr)

Comparison CO2e

Total GHG for State of Colorado1 130

Nationwide GHG Total2 2,245

% of State Total 11.1%

% of United States Total 0.64% 1

CDPHE Colorado Greenhouse Gas Inventory -2014 Update 

(https://www.colorado.gov/pacific/sites/default/files/APCOGHGInventory2014Update.pdf) 2 Derived from all 60 sectors of the 2011 NEI database and all 

50 states plus the District of Columbia. Puerto Rico, Virgin 

Islands and Tribal land was excluded.

Alternative A Cumulative Hazardous Pollutant and Mercury Emissions

Cumulative hazardous pollutants are a summation of those pollutants emitted by the 

combustion process of coal and the combustion of diesel fuel from equipment at the mine site 

or transferring coal to the Craig Generating Station. Similar to GHG and criteria pollutants, 

indirect HAP emissions were determined for a maximum, average, and Craig Only regional 

scenario as shown in Table 5.4-7. 

Table 5.4-7 Cumulative Emissions of Hazardous Air Pollutants (tpy)

Activity HAPs

Direct Emissions 9.17

Indirect Rail 0.02

Indirect Combustion Max 77.02

Indirect Combustion Avg. 64.32

Craig Combustion Only 77.02

Total Maximum 86.2

Total Average 73.5

Total Craig Only 86.2

The state of Colorado had a total of 195,455 tons of HAPs in 2011 as indicated by the NEI 

data. Nationwide, 9.05 mt were emitted. Table 5.4-8 compares the Alternative A HAP 

potential to the state and national totals as a percentage.

Table 5.4-8 HAP Emissions as Percentage of State and National Emissions

Percentage Comparison HAPs

Proposed Maximum % of Colorado 0.044%

Proposed Average % of Colorado 0.038%

Proposed Craig Only % of Colorado 0.044%

Proposed Maximum % of U.S. 0.00095%

Proposed Average % of U.S. 0.00081%

Proposed Craig Only % of U.S. 0.00095%

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 5-10

Mining Plan Modification Environmental Assessment
Chapter 5 – Cumulative Impacts

Estimated mercury emission rates from the Craig Generating Station are calculated based on 6 

mt of coal per year combusted. The MATS Rule was published in 2011 and sources had 3 or 4 

years to comply with the new standards. Therefore, Craig Station will comply with the new 

standard in 2015. Prior to compliance with the MATS rule indirect mercury emissions were 

estimated at 155 lb./yr, but after implementation of controls it drops to 62 lb./yr. Other 

sources of mercury are negligible (less than 0.01 lb/yr) when compared to the Craig Generating 

Station The 2011 NEI information for electric generating coal facilities in Colorado indicates 

that 745.8 lb. (0.37 tons) of mercury were emitted from coal facilities. The Craig Generating 

Station’s contribution assuming 6 mtpy is approximately 8.4 percent of the total to the state. 

Nationally, the total is 25.6 tons. The Craig Generating Station is approximately 0.12 percent. 

Alternative B Criteria Pollutant Cumulative Emissions

Alternative B comprises actual emissions for the mine, Craig Generating Station and the 

Hayden Generating Station from 2007 through 2014 and a maximum foreseeable combustion 

rate of 4 mtpy. Tables 5.4-9 through 5.4-26 outline the cumulative criteria pollutant 

emissions for each year using a maximum average and Craig Only regional emission rate for 

coal combustion. The maximum represents the higher rate between the Craig Generating 

Station and the Hayden Generating Station. All direct emissions are associated with actual 

APEN submitted data or actual throughput values. Comparison tables are also provided for 

each year and the maximum foreseeable throughput rate of 4 mtpy. Emissions from the 

surrounding four counties within the CIAA and the state in its entirety are compared against 

the Project-related values.

Table 5.4-9 Cumulative Emissions of Criteria Pollutants - 2007 (tpy)

 1 

Year Activity PM10 PM2.5 NOx CO VOC SO2

Direct Emissions 924 226 885 5,279 12.7 0.7

Indirect Combustion Max 3.17 1.44 138.65 11.35 1.05 49.84

Indirect Combustion Avg. 2.38 1.28 124.99 9.79 39.93 0.81

2007 Indirect Craig Combustion 1.59 1.11 111.32 11.35 0.57 30.02

Total Maximum 927 228 1,023 5,291 14 51

Total Average 927 228 1,010 5,289 53 41

Total Craig Only 926 227 996 5,291 13 31 1 The South Taylor pit was approved in 2007 and coal extraction began late in October of that year. Therefore, 

the amount of coal combusted at Craig that originated from South Taylor was only approximately 37,000 tons, 

which considerably less than all subsequent years.

Table 5.4-10 2007 Criteria Pollutants as Percentage of 2011 Regional Criteria 

Pollutant Emissions

Percentage Comparison PM10 PM2.5 NOx CO VOC SO2

Proposed Maximum % of 4 Counties 4.15% 3.92% 2.33% 6.25% 0.01% 0.76%

Proposed Average % of 4 Counties 4.15% 3.92% 2.30% 6.24% 0.04% 0.61%

Proposed Craig Only % of 4 Counties 4.14% 3.90% 2.26% 6.25% 0.01% 0.46%

Proposed Maximum % of Colorado 0.28% 0.22% 0.34% 0.37% 0.003% 0.09%

Proposed Average % of Colorado 0.28% 0.22% 0.33% 0.37% 0.010% 0.07%

Proposed Craig Only % of Colorado 0.28% 0.22% 0.33% 0.37% 0.002% 0.06%

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 5-11

Mining Plan Modification Environmental Assessment
Chapter 5 – Cumulative Impacts

Table 5.4-11 Cumulative Emissions of Criteria Pollutants - 2008 (tpy)

Year Activity PM10 PM2.5 NOx CO VOC SO2

Direct Emissions 924 226 885 5,279 12.7 0.7

Indirect Combustion Max 99.93 45.51 4,370 358 33.16 1,571

Indirect Combustion Avg. 74.95 40.32 3939 309 25.6 1,259

2008 Indirect Craig Combustion 49.98 35.13 3,509 358 18.05 946

Total Maximum 1,024 272 5,254 5,637 46 1,572

Total Average 999 267 4,824 5,588 38 1,259

Total Craig Only 974 261 4,393 5,637 31 947

Table 5.4-12 2008 Criteria Pollutants as Percentage of 2011 Regional Criteria 

Pollutant Emissions

Percentage Comparison PM10 PM2.5 NOx CO VOC SO2

Proposed Maximum % of 4 Counties 4.58% 4.68% 12.0% 9.85% 0.04% 23.3%

Proposed Average % of 4 Counties 4.47% 4.59% 11.0% 9.76% 0.03% 18.7%

Proposed Craig Only % of 4 Counties 4.36% 4.49% 10.0% 9.85% 0.02% 14.0%

Proposed Maximum % of Colorado 0.31% 0.27% 1.73% 0.40% 0.008% 2.82%

Proposed Average % of Colorado 0.30% 0.26% 1.59% 0.40% 0.007% 2.26%

Proposed Craig Only % of Colorado 0.30% 0.26% 1.44% 0.40% 0.006% 1.70%

Table 5.4-13 Cumulative Emissions of Criteria Pollutants - 2009 (tpy)

Year Activity PM10 PM2.5 NOx CO VOC SO2

Direct Emissions 1,015 253 929 5,617 9.6 0.7

Indirect Combustion Max 111.1 50.59 4,858 398 36.87 1,746

Indirect Combustion Avg. 83.33 44.83 4,380 343 28.47 1,400

2009 Indirect Craig Combustion 55.56 39.06 3,901 398 20.06 1,052

Total Maximum 1,126 304 5,787 6,015 46 1,747

Total Average 1,098 298 5,309 5,960 38 1,400

Total Craig Only 1,071 292 4,830 6,015 30 1,053

Table 5.4-14 2009 Criteria Pollutants as Percentage of 2011 Regional Criteria 

Pollutant Emissions

Percentage Comparison PM10 PM2.5 NOx CO VOC SO2

Proposed Maximum % of 4 Counties 5.04% 5.23% 13.2% 10.5% 0.04% 25.9%

Proposed Average % of 4 Counties 4.91% 5.13% 12.1% 10.4% 0.03% 20.8%

Proposed Craig Only % of 4 Counties 4.79% 5.02% 10.5% 10.5% 0.02% 15.6%

Proposed Maximum % of Colorado 0.34% 0.30% 1.90% 0.43% 0.008% 3.14%

Proposed Average % of Colorado 0.33% 0.29% 1.75% 0.42% 0.007% 2.51%

Proposed Craig Only % of Colorado 0.33% 0.29% 1.59% 0.43% 0.005% 1.89%

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 5-12

Mining Plan Modification Environmental Assessment
Chapter 5 – Cumulative Impacts

Table 5.4-15 Cumulative Emissions of Criteria Pollutants - 2010 (tpy)

Year Activity PM10 PM2.5 NOx CO VOC SO2

Direct Emissions 1,015 253 732 4,416 7.2 0.6

Indirect Combustion Max 119 54.1 5,195 425 39.42 1,867

Indirect Combustion Avg. 89.1 47.93 4,683 367 30.44 1,496

2010 Indirect Craig Combustion 59.41 41.77 4,171 425 21.45 1,125

Total Maximum 1,134 307 5,926 4,841 47 1,868

Total Average 1,104 301 5,415 4,783 38 1,497

Total Craig Only 1,074 295 4,903 4,841 29 1,126

Table 5.4-16 2010 Criteria Pollutants as Percentage of 2011 Regional Criteria 

Pollutant Emissions

Percentage Comparison PM10 PM2.5 NOx CO VOC SO2

Proposed Maximum % of 4 Counties 5.07% 5.28% 13.5% 8.46% 0.04% 27.7%

Proposed Average % of 4 Counties 4.94% 5.18% 12.3% 8.36% 0.03% 22.2%

Proposed Craig Only % of 4 Counties 4.80% 5.07% 11.2% 8.46% 0.02% 16.7%

Proposed Maximum % of Colorado 0.34% 0.30% 1.95% 0.34% 0.008% 3.35%

Proposed Average % of Colorado 0.34% 0.30% 1.78% 0.34% 0.007% 2.69%

Proposed Craig Only % of Colorado 0.33% 0.29% 1.61% 0.34% 0.005% 2.02%

Table 5.4-17 Cumulative Emissions of Criteria Pollutants - 2011 (tpy)

Year Activity PM10 PM2.5 NOx CO VOC SO2

Direct Emissions 1,015 253 706 4,267 7.0 0.6

Indirect Combustion Max 155. 70.78 6797 556 51.57 2443

Indirect Combustion Avg. 117 62.71 6127 480 39.82 1,958

2011 Indirect Craig Combustion 77.73 54.65 5,457 556 28.07 1,471

Total Maximum 1,171 324 7,503 4,823 59 2,444

Total Average 1,132 316 6,833 4,747 47 1,958

Total Craig Only 1,093 308 6,163 4,823 35 1,472

Table 5.4-18 2011 Criteria Pollutants as Percentage of 2011 Regional Criteria 

Pollutant Emissions

Percentage Comparison PM10 PM2.5 NOx CO VOC SO2

Proposed Maximum % of 4 Counties 5.24% 5.57% 17.1% 6.33% 0.05% 36.2%

Proposed Average % of 4 Counties 5.06% 5.44% 15.5% 8.29% 0.04% 29.0%

Proposed Craig Only % of 4 Counties 4.89% 5.30% 14.0% 8.43% 0.03% 21.8%

Proposed Maximum % of Colorado 0.36% 0.32% 2.47% 0.34% 0.011% 4.39%

Proposed Average % of Colorado 0.34% 0.31% 2.25% 0.34% 0.008% 3.51%

Proposed Craig Only % of Colorado 0.33% 0.30% 2.03% 0.34% 0.006% 2.64%

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Table 5.4-19 Cumulative Emissions of Criteria Pollutants - 2012 (tpy)

Year Activity PM10 PM2.5 NOx CO VOC SO2

Direct Emissions 1,518 403 726 4,423 5.8 0.6

Indirect Combustion Max 106 48.05 4,614 378 35.01 1659

Indirect Combustion Avg. 79.14 42.57 4,159 326 27.03 1,329

2012 Indirect Craig Combustion 52.77 37.1 3705 378 19.05 999

Total Maximum 1,624 451 5,340 4,801 41 1,659

Total Average 1,598 445 4,885 4,749 33 1,329

Total Craig Only 1,571 440 4,430 4,801 25 1,000

Table 5.4-20 2012 Criteria Pollutants as Percentage of 2011 Regional Criteria 

Pollutant Emissions

Percentage Comparison PM10 PM2.5 NOx CO VOC SO2

Proposed Maximum % of 4 Counties 7.26% 7.76% 12.1% 8.39% 0.03% 24.6%

Proposed Average % of 4 Counties 7.15% 7.65% 11.1% 8.30% 0.03% 19.7%

Proposed Craig Only % of 4 Counties 7.03% 7.57% 10.1% 8.39% 0.02% 14.9%

Proposed Maximum % of Colorado 0.49% 0.44% 1.76% 0.34% 0.007% 2.98%

Proposed Average % of Colorado 0.49% 0.44% 1.61% 0.34% 0.006% 2.39%

Proposed Craig Only % of Colorado 0.48% 0.43% 1.46% 0.34% 0.005% 1.79%

Table 5.4-21 Cumulative Emissions of Criteria Pollutants - 2013 (tpy)

Year Activity PM10 PM2.5 NOx CO VOC SO2

Direct Emissions 606 78 686 4,162 7.3 0.6

Indirect Combustion Max 127 57.91 5,561 455 42.2 1,999

Indirect Combustion Avg. 95.39 51.31 5,013 393 32.58 1,602

2013 Indirect Craig Combustion 63.6 44.71 4,465 455 22.97 1,204

Total Maximum 733 136 6,247 4,617 50 2,000

Total Average 701 129 5,699 4,554 40 1,602

Total Craig Only 669 123 5,151 4,617 30 1,205

Table 5.4-22 2013 Criteria Pollutants as Percentage of 2011 Regional Criteria 

Pollutant Emissions

Percentage Comparison PM10 PM2.5 NOx CO VOC SO2

Proposed Maximum % of 4 Counties 3.28% 2.34% 14.2% 8.07% 0.04% 29.7%

Proposed Average % of 4 Counties 3.14% 2.22% 13.0% 7.96% 0.03% 23.8%

Proposed Craig Only % of 4 Counties 2.99% 2.12% 11.7% 8.07% 0.02% 17.9%

Proposed Maximum % of Colorado 0.22% 0.13% 2.05% 0.33% 0.009% 3.59%

Proposed Average % of Colorado 0.21% 0.13% 1.87% 0.32% 0.007% 2.88%

Proposed Craig Only % of Colorado 0.20% 0.12% 1.69% 0.33% 0.005% 2.16%

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Table 5.4-23 Cumulative Emissions of Criteria Pollutants - 2014 (tpy)

Year Activity PM10 PM2.5 NOx CO VOC SO2

Direct Emissions 606 78 364 2,152 10.3 0.4

Indirect Combustion Max 155 70.43 6,763 554 51.32 2,431

Indirect Combustion Avg. 116 62.41 6,097 478 39.63 1,948

2014 Indirect Craig Combustion 77.35 54.38 5,431 554 27.93 1,465

Total Maximum 760 149 7,127 2,706 62 2,432

Total Average 722 140 6,461 2,630 50 1,948

Total Craig Only 683 132 5,794 2,706 38 1,465

Table 5.4-24 2014 Criteria Pollutants as Percentage of 2011 Regional Criteria 

Pollutant Emissions

Percentage Comparison PM10 PM2.5 NOx CO VOC SO2

Proposed Maximum % of 4 Counties 3.40% 2.56% 16.2% 4.73% 0.05% 36.1%

Proposed Average % of 4 Counties 3.23% 2.41% 14.7% 4.60% 0.04% 28.8%

Proposed Craig Only % of 4 Counties 3.05% 2.27% 13.2% 4.73% 0.03% 21.7%

Proposed Maximum % of Colorado 0.23% 0.15% 2.34% 0.19% 0.011% 4.36%

Proposed Average % of Colorado 0.22% 0.14% 2.12% 0.19% 0.009% 3.50%

Proposed Craig Only % of Colorado 0.21% 0.13% 1.90% 0.19% 0.007% 2.63%

Table 5.4-25 Cumulative Emissions of Criteria Pollutants – 4 Million (tpy)

Activity PM10 PM2.5 NOx CO VOC SO2

Direct Emissions 1,528 179 1,262 7,467 48 0.9

Indirect Combustion Max 339 154 14,798 1,211 112 5,319

Indirect Combustion Avg. 254 137 13,340 1,045 86.7 4,262

Indirect Craig Combustion 169 119 11,882 1,211 61.11 3,205

Total Maximum 1,866 332 16,059 8,678 160 5,320

Total Average 1,781 315 14,601 8,512 135 4,263

Total Craig Only 1,697 297 13,143 8,678 109 3,205

Table 5.4-26 4 Million Throughput Criteria Pollutants as Percentage of 2011 

Regional Criteria Pollutant Emissions

Percentage Comparison PM10 PM2.5 NOx CO VOC SO2

Proposed Maximum % of 4 Counties 8.35% 5.71% 36.5% 15.2% 0.13% 78.9%

Proposed Average % of 4 Counties 7.97% 5.42% 33.2% 14.9% 0.11% 63.2%

Proposed Craig Only % of 4 Counties 7.59% 5.11% 30.0% 15.2% 0.09% 47.5%

Proposed Maximum % of Colorado 0.57% 0.33% 5.28% 0.61% 0.029% 9.55%

Proposed Average % of Colorado 0.54% 0.31% 4.80% 0.60% 0.024% 7.65%

Proposed Craig Only % of Colorado 0.52% 0.29% 4.32% 0.61% 0.020% 5.75%

CO, NOx, and SO2 emissions are higher than all other criteria pollutants for all scenarios, both 

actual emissions and the foreseeable future maximum throughput of 4 mtpy. This is expected 

because the indirect combustion emissions dominate the cumulative impacts. The percentage 

contribution of Alternative B compared to the counties surrounding the study area produce a 

maximum of 17.1 percent of the NOx emissions; 10.5 percent of CO emissions, and 36.2 

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percent of SO2 emissions. Compared to the state, those percentages reduce to 2.47 percent, 

0.43 percent, and 4.36 percent, respectively. An annual throughput of 4 mtpy is greater than 

the actual emissions generating a higher overall percentage of regional totals. Under this 

scenario, the Project may produce up to 78.9 percent of the CIAA’s SO2 emissions and 9.6 

percent of the state emissions. NOx and CO contributions are also greater at 36.5 percent and 

15.2 percent for the four surrounding counties (5.3% and 0.61% for the state). 

Alternative B Cumulative GHG Emissions

All GHG emission calculations (Tables 5.4-27 through 5.4-30) are based on actual annual 

mining rates, that all coal was sent to the Craig Generating Station, and a foreseeable maximum 

future rate of 4 mtpy. 

Table 5.4-27 Cumulative Emissions of Greenhouse Gases (metric tonnes CO2e/yr)

Activity 2007 2008 2009 2010 2011 2012 2013 2014

Direct 76,039 74,573 68,520 52,807 50,806 48,906 53,720 44,801

Methane 

Release 758 2,746 2,001 1,439 1,320 1,173 1,280 1,376

Indirect 

Combustion 87,856 2,769,047 3,078,624 3,291,805 4,306,778 2,923,710 3,523,935 4,285,814

Total 164,653 2,846,365 3,149,145 3,346,051 4,358,904 2,973,789 3,578,935 4,331,990

Table 5.4-28 Cumulative Emissions of Greenhouse Gases (metric tonnes CO2e/yr)

Activity

4 mtpy

(2015-2019)1

Direct 159,782

Methane Release 61,104

Indirect Combustion 9,376,851

Total 9,597,737 1 4 mtpy is the maximum annual rate at which coal is mined and 

combusted between 2015 and 2019.

Table 5.4-29 GHG Emissions as Percentage of State and National Emissions 2007-

2014 

Activity 2007 2008 2009 2010 2011 2012 2013 2014

% of State Total 0.13% 2.19% 2.42% 2.57% 3.35% 2.29% 2.75% 3.33%

% of U.S. Total 0.01% 0.13% 0.14% 0.15% 0.19% 0.13% 0.16% 0.19%

Table 5.4-30 GHG Emissions as Percentage of State and National Emissions (4 mt) 

Activity 4 mtpy

% of State Total 7.38%

% of U.S. Total 0.43%

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 5-16

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Alternative B would contribute a small percentage of overall GHGs to the region and state. 

Maximums are no greater than 3.4 percent from 2007 to 2014. The foreseeable 4 mtpy is also 

low at 7.4 percent within the state and less than 1 percent of the total GHGs emitted 

nationwide. 

Alternative B Hazardous Pollutants and Mercury Cumulative Emissions

Cumulative hazardous pollutants are a summation of those pollutants emitted by the 

combustion process of coal and the combustion of diesel fuel from equipment at the mine site 

or transferring coal to Craig Generating Station. Similar to GHG and criteria pollutants, 

indirect HAP emissions were determined for a maximum, average and Craig Only regional 

scenario (Table 5.4-31). 

Table 5.4-31 Cumulative Emissions of Hazardous Air Pollutants (tpy)

Activity 2007 2008 2009 2010 2011 2012 2013 2014 4 mtpy

Direct Emissions 1.3 1.3 1.0 0.7 0.7 0.6 0.8 1.0 6.1

Indirect Maximum 0.5 15.2 16.9 18.0 23.6 16.0 19.3 23.5 51.4

Indirect Average 0.4 12.7 14.1 15.1 19.7 13.4 16.1 19.6 42.9

Indirect Craig Only 0.5 15.2 16.9 18.0 23.6 16.0 19.3 23.5 51.4

Total Maximum 1.8 16.5 17.8 18.8 24.3 16.6 20.1 24.5 57.5

Total Average 1.7 14.0 15.1 15.8 20.4 14.0 16.9 20.6 49.0

Total Craig Only 1.8 16.5 17.8 18.8 24.3 16.6 20.1 24.5 57.5

Compared to the state (195,455 tpy), Alternative B for the years of 2007 to 2014 includes only 

a maximum of 0.013 percent of the state HAPs and 0.00027 percent of the U.S.’s total. A 

foreseeable maximum throughput of 4 mtpy equates to 0.029 percent and 0.00064 percent, 

respectively. Therefore, Alternative B would emit an essentially negligible amount of HAPs 

when compared to the state and the rest of the country. 

Actual mercury emission rates from the Craig Generating Station, as provided by the EPA TRI, 

show that the maximum mercury emitted between 2007 and 2014 for the entire Craig 

Generating Station was 130 lbs or 0.065 tpy (prior to the installation of controls). The plant 

will become compliant with the MATS rule in 2015. As a result, the amount has dropped to 

the annual average of 44 lbs or 0.022 tons/year since 2010. 2013 TRI data showed that 1,070 

lbs (0.535 tons) of mercury were emitted within the state of Colorado. The Craig Generating 

Station contributes 4.02 percent of the total mercury emitted by facilities within Colorado. 

Similarly, the 2011 NEI information for electric generating coal facilities in Colorado indicates 

that 745.8 lbs (0.37 tons) of mercury were emitted from coal facilities. The Craig Generating 

Station’s average contribution since 2010 is approximately 5.9 percent of the total to the state. 

Nationally, the total is 25.6 tons. The Craig Generating Station is approximately 0.09 percent.

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Ozone Precursor Emissions

Discussion throughout Chapter 4 describes both NOx and VOC emissions and their comparison to the 

development of ozone. In addition, regional CDPHE monitors demonstrate that ozone NAAQS 

compliance is consistent for the past several years (Section 4.3.2.4). As a result, blasting and coal 

combustion associated with Colowyo mine and either the Hayden or Craig Generating Station does not 

pose a regional compliance issue.

5.4.2.5 Colorado Air Resource Management Modeling Study

The BLM funded the Colorado Air Resources Management Modeling Study (CARMMS) to 

better predict air quality impacts from future federal and non-federal energy development 

throughout the state. The study tracks impacts in each BLM field office to better understand 

the significance that oil and gas has had on impacted resources and populations.

1

CARMMS simulates future impacts of oil and gas development out to the year 2021. 

Projections for development are based on either the most recent field office Reasonably 

Foreseeable Development (RFD) document (high), or by projecting the current 5 year average 

development paces forward to 2021 (low). The medium scenario included the same well count 

projections as the high, but assumed restricted emissions, where the high assumed current 

development practices and on the books emissions controls and regulations (2012).2

The CARMMS project leverages the work completed by the West Jump Air Quality Modeling 

Study (WestJumpAQMS), and the base model platform (and associated model performance 

metrics) and meteorology are based on those products (2008).

The model (CAMx) is a one atmosphere photo-chemical grid model and represents state of the 

science methodology for modeling atmospheric chemistry and physics. The model accounts for 

every emissions source in the domain (global), including all of the coal fired power plants in the 

regional 4 km (6.4 miles) domain. Although these sources were not tracked using source 

apportionment technology, their impacts are included in the results, and in general the 

CARMMS data shows that air quality improves in the future. 

Criteria Pollutant Results from CARMMS

CARMMS evaluated regional air quality impacts for particulate matter, NO2 and O3. Table 

5.4-32 illustrates the average regional impacts compared to the applicable NAAQS. The 

findings suggest that the regional air quality surrounding the mine and the Craig Generating 

Station is compliant for those pollutants and averaging periods evaluated. All pollutants assume 

the 1st high average concentration. Note that all concentrations are the maximum values for 

each averaging period through the study timeframe of 2021.

1 Bureau of Land Management - http://www.blm.gov/co/st/en/BLM_Information/nepa/air_quality/carmms.html 2 Environ - CARMMS 2021 Modeling Results for the High and Medium Oil and Gas Development Scenarios 

http://www.blm.gov/style/medialib/blm/co/information/nepa/air_quality.Par.97516.File.dat/CAR%20MMS_Final_Rep

ort_w-appendices_012015.pdf

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Table 5.4-32 Regional NAAQS Comparison from CARMMS Data

Pollutant Averaging

Period

CARMMS

Average

(μg/m3)

NAAQS

(μg/m3) 

Percent 

of 

Standard

PM2.5

24-hr 22.19 35 63.4%

Annual 8.84 12 73.67%

PM10 24-hr 34.51 150 23.01%

NO2 1-hr 56.41 188 30.01%

O3

1 8-hr 72.31 75 96.41% 1. O3 concentrations are in units of ppb

5.4.2.6 Regional Haze, Visibility, and AQRV Improvements

In accordance with the Guidance for Setting Reasonable Progress Goals under the Regional 

Haze Program,3 states are required to establish “reasonable progress goals for each Class I 

area. The purpose is to improve visibility on the haziest of days and present no degradation on 

the clearest days. The Progress Goals are incremental in nature, such that, over time the 

visibility will reach natural background conditions.

Part of showing progression is to determine the glidepath. A comparison of baseline conditions 

in terms of deciviews (dv; a unit of visibility impairment) to natural conditions is conducted. 

Next, the annual average visibility improvement needed to reach natural conditions by 2064 - 

60 years. Finally, the annual average visibility is multiplied by the number of years in the first 

planning period. The result is the glidepath or uniform rate of progress needed to meet the 

goal natural conditions visibility by 2064.

Mount Zirkel Wilderness is the nearest Class I Area to the Craig and Hayden stations. A 2007 

study established the glidepath starting in 2004. Based on Interagency Monitoring of Protected 

Visual Environments (IMPROVE) from 2001 to 2004 the 20 percent worst visibility days 

baseline was determined to be 10.52 dv. Natural conditions of the worst 20 percent are 6.44 

dv creating an improvement need of 4.08 dv by 2064. An annual improvement of 0.068 dv is 

needed to meet the 2064 goal. The first planning period was set from 2004-2018. Therefore, 

the visibility goal by 2018 is 9.57 dv or a visibility increase of 0.95 dv.4

Flat Tops Wilderness falls within the CIAA. Using the same methodology as for Mount Zirkel, 

a baseline and natural conditions visibility was established using 2000 to 2004 IMPROVE data. 

Natural conditions are 6.54 dv, while baseline visibility is 9.61 dv. Over the span of 14 years 

during the first planning period, the visibility is projected to improve by 0.72 dv or 0.051dv per 

year.5 

The Craig Generating Station has two units that are BART eligible. All three units, 1, 2 and 3 

are included in the current Regional Haze SIP. As a result, both are required to meet specific 

NOx standards. To help meet applicable standards, SCR units have been installed to control 

NOx emissions. They have also installed wet lime scrubbers for SO2 control which have been 

3 U.S. EPA http://www.epa.gov/ttn/caaa/t1/memoranda/reasonable_progress_guid071307.pdf

4 Colorado SIP Mount Zirkel Technical Support Document

https://www.colorado.gov/pacific/sites/default/files/AP_PO_Mount-Zirkel-Wilderness_0.pdf 5 https://www.colorado.gov/pacific/sites/default/files/AP_PO_Flat-Tops-Wilderness_0.pdf

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operational since the end of 2004. According to modeling prepared as part of the BART 

analysis, NOx controls will improve visibility by 1.01 dv for Unit 1 and 0.98 dv for Unit 2. Unit 

3 is considered to be eligible for “Reasonable Progress”6. The Colorado SIP includes a 

determination for Unit 3 stating that it is reasonable to include a Selective Non-Catalytic 

Reduction (SNCR) for NOx which will improve visibility by 0.32 dv. 

Similarly, the Hayden Generating Station has two units identified as BART eligible in the SIP. 

Both are using lime spray dryers to control SO2. Unit 1 improves visibility by 0.10 dv and Unit 

2 by 0.21 dv. Hayden also currently controls NOX using SCR. Visibility improvements are 

estimated at 1.12 dv and 0.85 dv for Units 1 and 2, respectively.

The controls being implemented by the two power stations are helping to greatly improve the 

visibility in the region surrounding both the Mount Zirkel Wilderness and the Flat Tops 

Wilderness. In addition, the U.S. Forest Service has stated their concerns regarding visibility (in 

a letter to CDPHE in 1993) within the wilderness, which has subsequently been resolved. 

Colorado is also in agreement that control measures taken by the two facilities are sufficient in 

resolving the Forest Service concerns.

5.4.2.7 Regional Nitrate and Sulfate Deposition

Secondary aerosols form in the atmosphere from precursors gases (e.g., sulfur dioxide, NOx, 

and VOCs). The secondary aerosols of interest are nitrate (NO3-) and sulfate (SO4

2

-). Both 

negatively charged anions have an affinity toward ammonium creating ammonium nitrate and 

ammonium sulfate. All of the above secondary aerosols including ammonium compounds 

contribute to the formation of PM2.5. 

The U.S. Forest Service has had a monitoring site for fine aerosols with the Mount Zirkel 

Wilderness since July 1994. Data from that monitor is available at the IMPROVE network 

website operated by Colorado State University. The data are captured for 24 hours every 

three days. Data was evaluated between 2007 through August 2014. Estimated annual average 

concentrations for total PM2.5, NO3

-

, and SO4

2- were determined. 

All years suggested that there were considerable more SO4

2- ions in the atmosphere than 

nitrate. This is likely because ammonium will combine with NO3 until it is exhausted before 

forming ammonium sulfate. Thus, the measure of excess nitrate remaining is highly dependent 

on the amount of ammonium in the atmosphere.

During 2007 to 2014, the average PM2.5 concentration was 2.25 μg/m3, with SO4

2- contributing 

approximately 18 percent and NO3

- only 3.6 percent. Note that the vast majority of fine 

particulates in the area are comprised of organic mass and soil. Based on average aerosol data 

since 1994, those two components (organic mass and soil) comprise approximately 40 percent 

and 20 percent of total PM2.5, respectively.

With no change in the firing rate proposed for either the Craig or Hayden Generating Stations 

as part of any of the alternatives, these levels of NO3

- and SO42- deposition are not likely to 

6 CDPHE Regional Haze SIP Craig Station https://www.colorado.gov/pacific/sites/default/files/AP_PO_Craig-PowerPlant_0.pdf

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change as a result of those actions. Note that SCRs only control NOx emissions which are a 

ratio of NO to NO2. Thus there is no impact on NO3

- regarding the presence of SCRs.

5.4.2.8 No Action Alternative Cumulative Effects

The No Action Alternative would equate to the closure of the South Taylor pit immediately. 

All direct mining emissions would cease. Indirect railroad emissions would be likely increase 

somewhat as the rail distance from another mine to the Craig Generating Station would 

become greater. Comparatively, direct emissions for the No Action Alternative would be less 

than both Alternatives A or B with all production ending immediately. 

The maximum combustion rate at the Craig Generating Station over the past several years has 

been approximately 4.8 mtpy. In order to maintain that rate, Craig would have to obtain 2.3 mt 

from another mine to offset the loss of Colowyo. The No Action Alternative would have a 

lower overall cumulative emissions effect than Alternative A, which was discussed in detail 

above, but similar impacts to Alternative B. Both Alternatives A and B were shown to have no 

significant impact when compared to the nearby counties, state and the United States as a 

whole. Similarly, the No Action Alternative would create an insignificant comparative impact.

5.4.3 Geology

The CIAA for geological resources is the Project Area. The cumulative impacts from either 

Alternative A or Alternative B would be the continued removal of coal. Since 1977, Colowyo 

has mined between 0.3 and 6.4 mt of coal annually for a total of 150.9 mt of coal produced. 

Approximately 43 mt of coal would be mined under Alternative A or 33.1 mt of coal under 

Alternative B; 29 to 22 percent, respectively, of all the previously mined coal at Colowyo. 

Other geologic features in the area would remain in place and would not be impacted as they 

typically occur at greater depths than where mining would occur. Other actions that may 

cumulatively impact geological resources are limited to future mining (such as Colowyo’s 

proposed Collom expansion to the northwest) and oil and gas development. However, while 

future mining could possibly occur within the CIAA, such mining would not occur until the 

Project is complete. Oil and gas drilling would not be allowed until mine reclamation is 

completed. Cumulative impacts from these activities would be minor to moderate as geologic 

resources are removed. Mining and reclamation under the No Action Alternative would 

conclude sooner than both Alternative A and Alternative B. Consequently, cumulative impacts 

under the No Action are considered less than minor to moderate.

5.4.4 Water Resources

The CIAA for water resources is the Wilson Creek, Taylor Creek, and Good Spring Creek 

watersheds. Generally, much of the area is undeveloped, but may be a source for non-point 

sediment sources due to geology and land use. Other land use activities in these watersheds 

could include existing and future coal mining operations, oil and gas exploration, and agriculture 

(primarily grazing). Colowyo’s proposed Collom expansion would be located in the CIAA 

northwest of the Project Area. If authorized, coal mining would be initiated at the Collom 

expansion and would continue there for several decades; therefore, the CIAA would continue 

to be developed for coal extraction for an extended period. Oil and gas exploration within the 

Project Area could not go forward until mining operations and reclamation were complete. 

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However, oil and gas exploration could occur in other areas of the CIAA so coal mining and oil 

and gas development could occur concurrently within the CIAA. Oil and gas development 

would have potential to contribute to sedimentation and spills with potential cumulative 

impacts to water quality but would be minimized by their permitting requirements. Therefore, 

there would be no cumulative effects on water resources within the CIAA from these activities. 

With respect to agriculture, grazing is expected to be an important land use within the CIAA 

for the foreseeable future. Grazing within the Project Area would not be conducted under 

either Alternative A or B prior to final reclamation in order to prevent land use conflicts and to 

enhance the success of revegetation. Even after reclamation is complete, grazing in the Project 

Area would be restricted to approximately 60 percent of the authorized use to enhance the 

continued success of revegetation. Therefore for an extended period of time, there would be 

no effects from grazing on water resources in the Project Area. However, grazing in other 

portions of the CIAA would have the potential to increase erosion and sedimentation with 

potential cumulative impacts to water quality, but would be managed by the BLM. In the long 

term, the effects would be minor. 

In summary, given: 1) the minor impacts to water resources that have occurred as a result of 

mining over the past seven years; 2) the sequential nature of other potentially impacting land 

uses in the Project Area that would be deferred until after reclamation is complete; 3) the 

extended timeframe when there would be no impacts from those other activities in the Project 

Area; and 4) the predicted negligible to minor level of impacts predicted to occur for water 

resources under either Alternative A or Alternative B, only minor cumulative impacts to water 

resources are predicted. Mining and reclamation under the No Action Alternative would 

conclude sooner than both Alternative A and Alternative B. Cumulative impacts under the No 

Action are considered less than minor. 

5.4.5 Vegetation

The CIAA for vegetation is the Project Area. Additional mining under Alternative A or 

Alternative B would have the potential to cumulatively impact vegetation in the area. Along 

with the past, present, and reasonably foreseeable future actions, mining in the Project Area is 

likely to result in minor cumulative impacts to the region due to the disturbance and 

reclamation (some contemporaneous) of the area at the end of the life of the mine and reestablishment of local vegetative communities which has been ongoing. Sustainable grazing is 

anticipated to continue outside of the Project Area as currently practiced. Wildlife usage 

(including sage grouse) and vegetation communities are not likely to be adversely impacted over 

the long term. Reclamation activities would actually likely add seral and community diversity 

and increased production of forage for livestock, fish and wildlife. Mining and reclamation 

under the No Action Alternative would conclude sooner than both Alternative A and 

Alternative B. Consequently, cumulative impacts under the No Action Alternative are 

considered negligible.

5.4.6 Wetlands

The CIAA for wetlands is the Project Area. The cumulative impacts of additional mining to 

wetlands would occur from the removal of the wetlands within the Project Area and potential 

sedimentation of downstream wetlands. Given the measures in place and approved in PR02 as 

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Revised to reduce the potential for downstream impacts (Appendix B), these impacts have been 

and would continue to be minimal. Grazing, if not properly managed, can cause the structure 

and water quality of those wetlands to be impacted. Oil and gas development is generally 

required through federal lease stipulations or permit approval conditions to remain a set 

distance from wetlands, and few impacts occur. Additionally, increased road construction and 

use has the potential for an increase of sedimentation from the roads that are not paved. This 

impact would be mitigated as all roads constructed in the Project Area have included and would 

continue to include sedimentation control measures.

The CIAA for WOTUS (excluding wetlands) is the Wilson Creek, Taylor Creek, and Good 

Spring Creek watersheds. As presented in Section 4.7, neither Alternative A nor Alternative 

B would result in the loss of mapped WOTUS (excluding wetlands) in these watersheds. 

Therefore, this would not cumulatively add to the impacts to WOTUS (excluding wetlands). 

Other activities that have the potential to impact WOTUS (excluding wetlands) include oil and 

gas development and agricultural development through the potential loss of WOTUS or an 

increase of sedimentation into the channels. Recreation, livestock grazing, and other “nonground disturbing” activities are likely to add to cumulative impacts through a potential increase 

of sedimentation, particularly if these activities occur near WOTUS (excluding wetlands). 

All activities are limited through federal regulations under Section 404 of the CWA and 

regulations set by the USACE. The restrictions imposed by these regulations reduce the 

potential for developments to remove or impact wetlands and WOTUS in the area or require 

wetland impacts to be mitigated. Overall, Alternatives A and B would have minor cumulative 

impacts to wetlands and WOTUS, since any impacted wetlands and WOTUS have been or 

would be subject to mitigation. If any additional wetlands are located or delineated within the 

Project Area, they may be subject to additional mitigation. Mining and reclamation under the 

No Action Alternative would conclude sooner than both Alternative A and Alternative B. 

Consequently, cumulative impacts under the No Action are considered less than minor. 

5.4.7 Fish and Wildlife

The CIAA for fish and wildlife resources is the Project Area, which includes a large buffer zone 

around the disturbance areas.

When combined with past, present, and reasonably foreseeable future activities in the region, 

mining in the Project Area would cumulatively contribute to impacts to fish and wildlife species. 

This cumulative impact would be relatively minor given the large amount of similar undisturbed 

habitat that occurs in the region and because the area would be reclaimed to pre-disturbance 

conditions at the end of the Project.

Other activities in the region have the potential to cumulatively impact wildlife. Livestock 

grazing can create competition for grazing resources between cattle and big game species. The 

Morgan Creek Ranch is located in the vicinity of the Project Area. The Morgan Creek Ranch

participates in the Ranching for Wildlife program for this area that was created in 1993 through 

a voluntary cooperative agreement between the landowner (Colowyo) and the CPW. This 

program provides Colorado residents with the opportunity to hunt on private ranch land 

normally closed to the public (CPW 2015b). Participating ranches provide public hunting 

recreation access to their land free of charge to those who draw licenses. The ranch includes 

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approximately 30,265 acres, with 25,156 acres owned by Colowyo. Livestock grazing on the 

ranch is limited to mid-May through mid-October due to the local climate and a relatively short 

growing season. Rotational grazing has been implemented using well-maintained boundary and 

cross fences, along with water developments. Long-term planning for grazing management and 

wildlife habitat improvement continues with considerations of weather conditions and resource 

management. Wildlife habitat management objectives are met using a wide range of 

improvements including grazing management, prescribed burning, water development, and 

riparian restoration. Managing livestock grazing on the Morgan Creek Ranch for the mutual 

benefit of wildlife would reduce potential cumulative impacts on wildlife in the area resulting 

from grazing. Future oil and gas development would have the potential to displace wildlife 

species from an area for the life of those projects. However, oil and gas development on both 

federal and state leases is strictly regulated and subject to extensive wildlife protection 

mitigation measures and thus would be analyzed independently should such development occur. 

Dispersed recreation may disturb individual animals and result in minor and temporary 

displacement. Cumulative impacts from these activities would likely be negligible.

The additional surface disturbance created by either Alternative A or B would increase the 

potential for sedimentation to occur and therefore may potentially impact fisheries downstream 

of the Project Area. However, with the implementation of design features (Section 2.2.3 and 

Appendix B), the potential for sedimentation impacts would be small. Therefore, the 

cumulative impacts to fisheries would also be negligible. Mining and reclamation under the No 

Action Alternative would conclude sooner than both Alternative A and Alternative B. 

Consequently, cumulative impacts under the No Action are considered less than negligible.

5.4.8 Special Status Species

The CIAA for special status species is the Project Area plus a one mile (1.6 km) buffer around 

the disturbance area. The CIAA for the Colorado River fish species and western yellow-billed 

cuckoo extends to the Yampa River in a two mile (3.2 km) buffer surrounding the Craig 

Generating Station. Continued development of mining operations in the Project Area would 

contribute incrementally to other surface uses that occupy and adversely modify habitat for the 

special status species that occur. 

GSG is a special status species of concern. Design features (Section 2.2.3 and Appendix B) 

associated with reclamation would focus on restoration of the sagebrush steppe vegetative 

community for the specific benefit of GSG with a planned post-mining increase in GSG habitat 

when compared with the pre-mining condition (Appendix B, Section III). The above measures 

are also in addition to mitigation measures for GSG that Colowyo is required to implement 

under their current surface mining permit for the Colowyo mine approved by CDRMS.

Alternative A would not impact any PHMA but would directly impact 692.5 acres and indirectly 

impact 2,543.3 acres of GHMA. Given the combination of design features (Section 2.2.3 and

Appendix B, Section III) that would be implemented as requirements under either Alternative 

A or Alternative B and other reasonably foreseeable future actions, the cumulative impacts to 

GSG in combination with other past and present actions, would be minor to negligible.

The Colorado River fish are also of particular concern. Other activities that occur in the 

region would have the potential to result in water depletions including future mining at 

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Colowyo. However, any future depletion(s) would be subject to RIPRAP and would be offset 

through funding of the RIPRAP program. 

Given the combination of BMPs and design features that would be implemented as 

requirements under Alternative A or B and other reasonably foreseeable actions in the CIAA, 

these actions would not be expected to appreciably change the current aquatic conditions in 

the Yampa River. Consultation with the USFWS under Section 7 of the ESA has also included 

several conservation measures designed to mitigate cumulative impacts to the Colorado River fish 

species and western yellow-billed cuckoo. 

Neither action alternative would be expected to directly contribute to cumulative impacts to 

the Colorado River fish species or western yellow-billed cuckoo. However, indirect impacts from 

the combustion of Colowyo coal at the Craig Generating Station would continue to release 

mercury. Some portion of this mercury is reasonably likely to end up in the Yampa River which 

would cumulatively impact the Colorado River fish and western yellow-billed cuckoo. It is also 

reasonably foreseeable that combustion at the Craig Generating Station would continue to 

occur if coal was not supplied by Colowyo. Therefore, while mining in the Project Area would 

result in cumulative impacts to the Colorado River fish and western yellow-billed cuckoo from 

water depletions, mercury deposition would occur even if mining was eliminated in the Project 

Area (i.e., No Action Alternative) as coal would be supplied from elsewhere. 

Alternative A or Alternative B, in conjunction with other past, present, and reasonably 

foreseeable future actions, would contribute negligible to minor long-term cumulative loss of 

habitat in the CIAA for Great Basin spadefoot, mountain plover, Columbian sharp-tailed grouse, 

burrowing owl, Brewer’s sparrow, and white-tailed prairie dog until reclamation restores 

habitat. Further, Alternatives A or B, in conjunction with other past, present, and reasonably 

foreseeable future actions, would contribute negligible to minor short-term to long-term 

cumulative loss of foraging habitat in the CIAA for ferruginous hawk, bald eagle, American 

peregrine falcon, and Townsend’s big-eared bat. All impacts on special status species would be 

negligible after successful reclamation. Mining and reclamation under the No Action Alternative 

would conclude sooner than both Alternative A and Alternative B. Consequently, cumulative 

impacts under the No Action are considered less than negligible.

5.4.9 Cultural and Historic Resources

The CIAA for cultural resources is the Project Area, which provides a large buffer zone around 

the disturbance areas. 

Most cultural resources tend to degrade over time due to natural processes but many survive 

for thousands of years. Modern human activity can exacerbate the damage that naturally 

occurs to cultural resources. Cumulative impacts to cultural resources can be broad and 

include past, present, and future activity within and adjacent to the Project Area as well as the 

surrounding area viewshed. The CIAA has been historically used for cattle ranching, mining, 

and recreational activities such as hunting. Any extant historic properties (i.e., NRHP-eligible 

cultural resources) within the CIAA are more likely to have sustained impacts as a result of 

prior ranching/grazing activities or other historic land-use activities than from mining. 

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Continued use and/or development of the area would have the potential to detract from the 

integrity of cultural resources directly through physical disturbance or indirectly through the 

degradation of the historical environmental setting. Increased utilization of the area also 

increases the potential for illegal collection or vandalism of cultural resource sites. Conversely, 

the development of the area would result in additional cultural resource studies. The 

information and data gained from these potential studies would be valuable to the overall 

knowledge of the area and have the potential to aid in the mitigation of unknown adverse 

effects. 

The potential impacts of Alternatives A and B are avoided through implementing design 

features and mitigation measures described in Sections 2.2.3 and 4.10.4, respectively. Similar 

measures would be implemented for other types of federal undertakings and would also limit 

cumulative impacts to cultural resources. Since no impacts to NRHP-eligible or “needs data”

cultural resources have occurred or are predicted under Alternatives A or B, there would be

no cumulative impacts. Mining and reclamation under the No Action Alternative would 

conclude sooner than both Alternative A and Alternative B. Similarly, there would be no 

cumulative impacts under the No Action Alternative.

5.4.10 Indian Concerns

The CIAA for Indian concerns is the Project Area, which provides a large buffer zone around 

the disturbance areas. None of the tribes contacted indicated areas of concern. Since no 

impacts to Indian concerns have occurred or are predicted under Alternatives A or B, there 

would be no contribution to cumulative impacts to Indian concerns in the region. Mining and 

reclamation under the No Action Alternative would conclude sooner than both Alternative A 

and Alternative B. There would be no cumulative impacts under the No Action Alternative.

5.4.11 Socioeconomics

The CIAA for socioeconomics includes Moffat, Rio Blanco, and Routt counties. The individuals 

and businesses that would be affected by the Project would be primarily in these counties, with 

the cumulative effects greater for the individuals and businesses in Moffat County where the 

Colowyo mine is located. The social and economic structures and relationships that are in 

place in the CIAA in support of previous and current mining and other activity in the area are 

described in Section 3.12, in addition to the local, mine-related employment and activity. The

incremental socioeconomic impacts of Alternatives A and B would include a constant level of 

employment and economic contribution from tax, royalty, and service revenues for the next 

two and four years, respectively. Cumulatively, the mining in these counties including that 

which occurs at the Trapper, Foidel Creek, and Deserado mines; and the reasonably 

foreseeable Collom expansion at the Colowyo mine; contribute to the economy and need for 

services in the CIAA. There is a cumulative need for housing, schools, retail, food services, and 

municipal services such as police, fire, etc. because of the presence of (and active mining at) all 

of these mines within the CIAA. Consequently, the eventual closure of these mines will have 

an adverse cumulative impact to these factors in the CIAA which would be more substantial 

depending on the timing of the cessation of mining at each facility.

Under the No Action Alternative, the socioeconomic impacts discussed in Section 4.12 would 

happen two or four years earlier, respectively, than under Alternative A or B. This means that 

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under the No Action Alternative, the economic loss would be $65 million to $131 million more 

than under the action alternatives, because the CIAA would not benefit from those payments 

during those years. Currently, the counties in the CIAA are experiencing economic impacts 

related to the reduction in the agricultural and ranching economies, and the potential reduction 

in oil and gas development due to the presence of GSG habitat (Jaffe 2015). The management 

of public lands under the direction of the Northwest Colorado Greater Sage Grouse LUP/FEIS 

(BLM 2015), may cause reductions in employment in the CIAA due to land use restrictions. 

Impacts in local areas could be dramatic and significant, especially in areas where mineral 

exploration and development, including the development of minerals other than oil and gas 

(e.g., coal and several salable and locatable minerals), is a sizeable contributor to employment, 

output, earnings, and tax revenues (BLM 2015). Therefore, the economic impacts under the 

No Action Alternative would have greater incremental cumulative economic impacts, and add 

to the economic uncertainty, within the CIAA than either action alternative when compared to 

the decline in other industries in the CIAA.

5.4.12 Visual Resources

The CIAA for visual resources is the Project Area and a 20 mile (32 km) buffer to account for 

the viewshed from the highest point in the disturbance area. While the location of the mine 

and ancillary facilities are topographically screened, visual disturbances associated with the 

mining operations are intermittently visible for travelers on the highways north of the Project 

Area. Combined with other ongoing surface disturbing activities within the Project Area, 

including the proposed Collom expansion to the Colowyo mine and sand and gravel operations

(approximately 5 [8.0 km] to 8 miles [12.8 km]) north and northwest of the Project Area), 

mining in the Project Area cumulatively contributes to a visually impacted landscape. Under 

both Alternative A and B, mining would continue; mining disturbance would increase in areas 

intermittently visible north of the Project Area until mining is complete, and would contribute 

to cumulative effects to visual resources. Under either action alternative, reclamation would 

include recontouring and revegetating the South Taylor pit. Areas of valley fill would 

permanently alter area topography and would be intermittently visible in the landscape, 

contributing to cumulative effects. Alternative A would have potentially greater cumulative 

impacts as it would disturb a larger footprint than Alternative B. Residual effects of mining 

would be apparent for a number of years until the reclaimed area naturalizes with mature 

vegetation. Cumulative impacts to visual resources would be minimized due to reclamation 

efforts. Mining and reclamation under the No Action Alternative would conclude sooner than 

both Alternative A and Alternative B. Consequently, cumulative impacts under the No Action 

are considered negligible. 

5.4.13 Recreation

The CIAA for recreation is Moffat and Rio Blanco Counties. Under either Alternative A or 

Alternative B, recreation, including hunting by the general public, would not be allowed to 

occur within the Project Area. Only mine employees or their families are currently allowed to 

access Colowyo-owned lands (excluding the active mining areas) during hunting season. There 

would not be any loss of recreational potential, on Colowyo privately owned land, because

public access has never been allowed. The public parcels of land within the Project Area are 

closed to public access for safety reasons. The continuation of programs such as Ranching for 

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Wildlife that provides Colorado residents with the option to hunt on private ranch land 

normally closed to the public, would offer additional hunting opportunities. Recreational trends 

in Moffat and Rio Blanco counties would continue. Cumulative impacts to recreation would be 

negligible. Mining and reclamation under the No Action Alternative would conclude sooner 

than both Alternative A and Alternative B. Consequently, cumulative impacts under the No 

Action are considered less than negligible.

5.4.14 Paleontology

The CIAA for paleontological resources is the Project Area. Mining under Alternative A or 

Alternative B could incrementally add to the potential impacts on paleontological resources in 

the Project Area. Other activities that may impact paleontological resources include future oil 

and gas development and additional mining. Activities such as recreational hunting that may 

occur within the Project Area are limited due to the fact that the Project Area is closed to the 

public. Future ground disturbing activities associated with mining within the Project Area 

would be subject to paleontological protection measures. Given the small area disturbed 

relative to the overall large land area of the region, as well as the limited number of surface 

disturbing activities other than mining that may occur on the privately held Colowyo land, 

cumulative impacts would be negligible. Mining and reclamation under the No Action 

Alternative would conclude sooner than both Alternative A and Alternative B. Consequently, 

cumulative impacts under the No Action are considered less than negligible.

5.4.15 Access and Transportation

The CIAA for access and transportation includes Moffat and Rio Blanco Counties. Mining 

under Alternative A or Alternative B would maintain mine-related infrastructure for traffic. 

The tax revenue generated from mining would contribute to the maintenance of public roads in 

the counties. The number of mine employees and associated traffic volume would increase 

under Alternative A, but would not change from current levels under Alternative B due to 

lower annual tons of coal being mined. Under Alternative B this relatively constant mine traffic 

would be included in the overall traffic volume for the counties which varies somewhat 

seasonally due to tourism and hunting. The cumulative impacts of wear and tear on the 

roadways from mine traffic would be negligible in the overall context of the other sources of 

traffic. However, if the mine production rate rose to the maximum permitted level for several 

years under Alternative A, the traffic volume both inside the mine permit boundary and outside 

the boundary on county and state roads would likely increase. Regardless of such an increase 

in production, the cumulative impacts from the relatively small incremental increase in mine 

traffic would remain negligible. Mining and reclamation under the No Action Alternative would 

conclude sooner than both Alternative A and Alternative B. Consequently, cumulative impacts 

under the No Action are considered less than negligible.

5.4.16 Solid and Hazardous Waste

The CIAA for solid and hazardous waste is the Project Area. There are no impacts to the 

environment due to solid and hazardous wastes anticipated for any of the Alternatives; 

therefore, there would be no cumulative impacts.

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5.4.17 Noise

The CIAA for noise is the Project Area, the railroad, and residences within 0.5 mile (0.8 km) of 

the Project Area. The principal noise sources related to continued mining operations include 

blasting, vehicles, the railroad, and noise from other facilities such as for mine vehicle 

maintenance. While noise would generally increase within the Project Area under Alternative 

A due to increased production and number of trains leaving the loadout, most of the noise 

would attenuate before reaching the mine permit boundary. As the rate of mining would 

remain at current levels, there would be no changes to noise under Alternative B. The nearest 

residences occur approximately one to three miles (1.6 to 4.8 km) from the Project Area to 

the south and southeast. Given the topography and vegetation within the CIAA, most noise 

would attenuate before reaching these residences. In conjunction with other past, present, and 

reasonably foreseeable future land uses within the CIAA, the mining under Alternative A or 

Alternative B would result in negligible cumulative impacts to noise in the region. Mining and 

reclamation under the No Action Alternative would conclude sooner than both Alternative A 

and Alternative B. Consequently, cumulative impacts under the No Action are considered less 

than negligible.

5.4.18 Livestock 

The CIAA for livestock grazing includes the five grazing allotments within the permit boundary. 

Under both Alternative A and B there would be a short-term reduction in the availability of 

grazing within the project area. This would cumulatively add to impacts on livestock grazing in 

the affected grazing allotments by reducing available forage. Grazing is one of the post-mine 

land uses targeted by the reclamation plan in Colowyo’s PR02 as Revised (Appendix B) and, 

upon completion of mining, the mine area would be restored for future livestock grazing at 60 

percent of the authorized use. Other activities in the allotments, such as oil and gas 

development, would also contribute to the cumulative impacts on grazing activities; although 

the dispersed and time limited nature of oil and gas operations would result in negligible 

impacts over the long term as well. The cumulative reduction of the available forage in the 

allotments would be negligible to minor because grazing would again be available after 

reclamation. Mining and reclamation under the No Action Alternative would conclude sooner 

than both Alternative A and Alternative B. Consequently, cumulative impacts under the No 

Action are considered less than negligible. 

5.4.19 Soils

The CIAA for soils is the Project Area. Mining under either Alternative A or Alternative B

would contribute to the cumulative impacts to soil resources from other surface disturbing 

activities such as oil and gas development. However, because oil and gas development within 

the CIAA would not be allowed until mining and reclamation are complete, those impacts 

would be negligible. Mining would likely increase erosion in impacted areas; however, the 

implementation of the Reclamation Plan under PR02 as Revised (Appendix B), as well as other 

design features (Section 2.2.3) and BMPs would reduce the likelihood of increased 

sedimentation outside of the Project Area. Additionally, no other surface disturbing activities 

would be allowed within the Project Area until post-mining reclamation of the area is complete. 

Therefore, the cumulative impacts on soil resources would be minor. Mining and reclamation 

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under the No Action Alternative would conclude sooner than both Alternative A and 

Alternative B. Consequently, cumulative impacts under the No Action are considered less than 

minor.

5.4.20 Alluvial Valley Floors

The CIAA for AVFs is the Wilson Creek, Taylor Creek, and Good Spring Creek watersheds, 

which is the same as the Water Resources CIAA (Section 5.4.4). Agricultural activities in 

these watersheds could have directly affected these AVFs in the past by farming in the 

bottomlands; this would be a minor cumulative impact when compared with Alternatives A and 

B. Otherwise, ongoing and future agricultural activities are expected to be primarily grazing 

(Section 5.4.4). These, as well as past, existing, and future coal mining operations (e.g., 

proposed Collom expansion), and oil and gas exploration, could also indirectly affect AVFs 

through sedimentation, spills or releases, and flow reduction (Section 5.4.4). In summary, 

given: 1) the negligible impacts to AVFs that have occurred as a result of mining over the past 

seven years and the past minor impacts as a result of agriculture; 2) the sequential nature of 

other potentially impacting land uses in the CIAA that would be deferred until after reclamation 

is complete; 3) the extended timeframe when there would be no impacts from those other 

activities; and 4) the predicted negligible level of impacts predicted to occur for AVFs under 

either Alternative A or Alternative B, only negligible cumulative impacts to AVFs would occur. 

Mining and reclamation under the No Action Alternative would conclude sooner than both 

Alternative A and Alternative B. Consequently, cumulative impacts under the No Action are 

considered less than negligible.

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CHAPTER 6 COORDINATION AND CONSULTATION 

6.1 AGENCIES/PERSONS CONSULTED

The following people or agencies were consulted prior to and during the preparation of this 

EA:

• U.S. Fish and Wildlife Service (USFWS)

• Colorado Department of Public Health and Environment (CDPHE)

• Office of Archaeology and Historic Preservation, History Colorado

• Eastern Shoshone Tribal Council

• Ute Mountain Ute Tribal Council

• Ute Indian Tribal Council

• Southern Ute Tribal Council

• Rio Blanco County

• Affected Landowners

6.1.1 Public Comment Process

Public scoping comments were solicited via public outreach legal notices published in the Rio 

Blanco Herald Times and the Craig Daily Press on May 21 and 22, 2015, and again on June 4 and 5, 

2015, respectively (Appendix A). The legal notice was also posted in public locations in Craig 

and Meeker. In addition, a public outreach notice letter (May 21, 2015) was mailed to 98

identified interested parties including BLM, Indian tribes, state agencies, city and county 

governments, adjacent landowners, and other interested parties. A revised outreach letter was 

sent out on May 27, 2015, to inform the public that the venue for the public meeting had been 

changed in order to accommodate larger attendance. Further, on May 28 and 29, revised legal 

notices were again published in the Rio Blanco Herald Times and the Craig Daily Press respectively 

(Appendix A) informing the public that the meeting location had been changed.

In order to reach a larger audience, OSMRE created the following project website:

http://www.wrcc.osmre.gov/initiatives/colowyoMineSouthTaylor.shtm

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The website became live on May 21, 2015, which provided the legal notices, outreach notices 

letters, outreach meeting materials, mailing address, and an email address for comments to be 

sent. The legal notices and letters invited the public to comment on issues of concern for the 

Project, and informed the interested citizens of the public outreach meeting held on June 10, 

2015, at the Moffat County Fairgrounds, Grandstands building, 601 Victory Way, Craig, CO,

from 4:00 PM until 8:00 PM. A total of 632 people attended and 447 submitted comment forms

at the meeting. A total of 521 comment forms and 662 email comments, for a total of 1,183 

comment submittals, were received by the end of the comment period. Public comments were 

received through June 15, 2015 and included the following issues:

• General support of the project;

• NEPA compliance;

• Impacts to air quality and climate change;

• Impacts to socioeconomics if the mine were to shut down;

• The need for an EIS;

• Impacts to rare or imperiled fish, wildlife, and plants; and

• Mitigation for impacts.

All comments received have been considered in the preparation of this document. A summary

discussion of the issues raised during scoping is discussed in Section 1.6. 

OSMRE released the EA on July 27, 2015, for the public to review and comment for a 19 day 

period ending on August 14, 2015. Comments were accepted via mail and email. A total of 

9,525 comment letters or emails were received. Revisions were made to the EA, as appropriate, and 

responses to comments prepared as part of the Mining Plan Decision Document. The comment 

and response document is provided as Appendix F.

6.1.2 US Fish and Wildlife Section 7 Process

On August 5, 2015, OSMRE reinitiated the Section 7 consultation process with USFWS when they 

submitted a biological assessment (BA). The BA requested to reinitiate the consultation process due to 

the indirect effects of mercury and selenium deposition on listed species. A revised BA was submitted 

on August 25, 2015 and a BO was issued by USFWS on August 27, 2015 (Appendix D).

6.1.3 Tribal Consultation

On June 16, 2015, OSMRE sent a letter to each of the tribes explaining the project and requesting 

consultation under Section 106 of the National Historic Preservation Act of 1966 (as amended), and 

none of the Tribes responded. On July 15, 2015, OSMRE sent a letter to each of the tribes explaining 

that the EA and FONSI would be available for review and comment July 27, 2015, through August 14, 

2015.

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6.2 COOPERATING AGENCIES

The following is a list of Cooperating Agencies for the preparation of this EA:

• Bureau of Land Management (BLM)

• Colorado Department of Natural Resources (DNR), including the Executive Director’s 

Office, Colorado Division of Reclamation Mining and Safety (CDRMS), Colorado 

Division of Parks and Wildlife (CPW), and Colorado State Land Board (SLB)

• Moffat County

Table 6.2-1 lists the participants in the preparation of this EA from the Cooperating Agencies. 

Table 6.2-1 Participants from Cooperating Agencies

Name Title

Tim Wilson, BLM Assistant Field Manager, Little Snake Field Office

Kathy McKinstry, BLM Planning and Environmental Coordinator, Little Snake 

Field Office

Jennifer Maiolo, BLM Mining Engineer, Little Snake Field Office

Desa Ausmus, BLM Wildlife Biologist, Little Snake Field Office

Chad Meister, BLM Natural Resource Specialist (Air Quality), Colorado 

State Office

Kathleen Staks, DNR Assistant Director for Energy

Dan Hernandez, CDRMS Senior Environmental Protection Specialist

Rob Zuber, CDRMS Environmental Protection Specialist

Phillip Courtney, SLB Solid Minerals Leasing Manager

Mike Warren, CPW Energy Liaison, Northwest Region

Chuck Grobe, Moffat 

County County Commissioner

Jeff Comstock, Moffat 

County Director, Natural Resources Department

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6.3 PREPARERS AND PARTICIPANTS

Table 6.3-1 shows a list of the preparers of this EA and those who participated in the 

preparation of this EA from OSMRE.

Table 6.3-1 Office of Surface Mining Reclamation and Enforcement

Name Title

Robert Postle Manager, Program Support Division

Marcelo Calle Manager, Field Operations Branch

Nicole Caveny Environmental Protection Specialist

Bobbi Hernandez Civil Engineer

Alex Birchfield Ecologist

Jacob Mullinix Soils Scientist

Table 6.3-2 shows a list of the preparers of this EA and those who participated in the 

preparation of this EA from the third party consultants Stantec Consulting and Trinity 

Consultants.

Table 6.3-2 Consultants

Name Title Resource/Role

Greg Brown, Stantec 

Consulting Principal Review and project oversight

Doug Koza, Stantec 

Consulting Environmental Scientist Project Manager

Neil Lynn, Stantec Consulting Environmental Scientist Wildlife, Special Status Species

Karla Knoop, Stantec 

Consulting Environmental Scientist Water Resources, Geology, Topography, Soils, Alluvial Valley Floors

Schelle Davis Stantec 

Consulting Environmental Scientist Visual Resources

Stephanie Lauer, Stantec 

Consulting Environmental Scientist

Socioeconomics, Environmental Justice, 

Livestock Grazing, Solid and Hazardous 

Wastes, Noise

Jenni Prince-Mahoney, Stantec 

Consulting Environmental Scientist

Cultural Resources, Indian Concerns, 

Paleontology, Recreation, 

Transportation/Access

Daniel Heiser, Stantec 

Consulting Manager, Engineering Air Quality and Modeling

Eric Clark Stantec Consulting Project Engineer Air Quality and Modeling

Nick Faust, Stantec Consulting GIS Analyst Geographic Information Systems, 

Mapping

Marcia Williamson, Stantec 

Consulting Project Coordinator Public Comment Analysis

David E. B. Strohm II, Trinity 

Consultants Managing Consultant Air Quality and Modeling

OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 6-4

Mining Plan Modification Environmental Assessment
Chapter 7 – References

CHAPTER 7 REFERENCES

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OSMRE Colowyo Coal Mine, South Taylor/Lower Wilson Permit Expansion Area Project 7-13

Mining Plan Modification Environmental Assessment