ENVIRONMENTAL ASSESSMENT

For

Jim Bridger Coal Mine Complex

Mining Plan Modification for Federal Coal 

Lease WYW02727

April 2018

Environmental Assessment

For

Jim Bridger Coal Mine Complex Mining Plan Modification for 

Federal Coal Lease WYW02727

United States Department of the Interior

Office of Surface Mining Reclamation and Enforcement

April 2018

Jim Bridger Coal Mine Complex Mining Plan Modification for Federal Coal Lease WYW02727 

Environmental Assessment

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CONTENTS

1. Purpose and Need ............................................................................................................................... 1

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

1.2. Background .................................................................................................................................... 3

1.2.1. Statutory and Regulatory Background ................................................................................... 4

1.3. Purpose and Need........................................................................................................................... 4

1.4. Relationship to Statutes, Regulations, and Other Agency Plans.................................................... 5

1.4.1. Statutes and Regulations........................................................................................................ 5

1.4.2. Other Agency Plans................................................................................................................ 6

1.5. Authorizing Actions....................................................................................................................... 7

1.6. Scoping, Outreach, and Issues Identification ................................................................................. 7

2. Proposed Action and Alternatives..................................................................................................... 7

2.1. Introduction .................................................................................................................................... 7

2.1.1. Existing Operations at Bridger Mine Complex...................................................................... 8

2.2. Description of Alternatives .......................................................................................................... 18

2.2.1. Proposed Action................................................................................................................... 18

2.2.2. No Action Alternative.......................................................................................................... 24

2.2.3. Alternatives Considered but Eliminated from Detailed Analysis........................................ 25

3. Affected Environment ...................................................................................................................... 27

3.1. Introduction .................................................................................................................................. 27

3.2. General Setting............................................................................................................................. 29

3.3. Air Quality and Climate Change .................................................................................................. 29

3.3.1. Local Climate and Meteorology........................................................................................... 29

3.3.2. Air Quality ........................................................................................................................... 30

3.3.3. Climate Change.................................................................................................................... 39

3.4. Cultural Resources ....................................................................................................................... 41

3.4.1. Cultural Context................................................................................................................... 41

3.4.2. Known Cultural Resources .................................................................................................. 42

3.4.3. Native American Religious Concerns.................................................................................. 44

3.5. Fish and Wildlife.......................................................................................................................... 44

3.5.1. Common Wildlife ................................................................................................................ 44

3.5.2. Big Game ............................................................................................................................. 44

3.5.3. Migratory Birds, including Raptors ..................................................................................... 48

3.5.4. Fish....................................................................................................................................... 50

3.6. Geology and Minerals.................................................................................................................. 50

3.6.1. Geology................................................................................................................................ 50

3.6.2. Minerals ............................................................................................................................... 53

3.7. Socioeconomics............................................................................................................................ 53

3.7.1. Population ............................................................................................................................ 54

3.7.2. Employment and Income ..................................................................................................... 54

3.7.3. Housing ................................................................................................................................ 54

3.7.4. Economy .............................................................................................................................. 55

3.8. Soils.............................................................................................................................................. 56

3.8.1. Soil Mapping Observations.................................................................................................. 56

3.8.2. Baseline Soil Assessment..................................................................................................... 57

3.9. Topography and Physiography..................................................................................................... 58
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3.10. Vegetation .................................................................................................................................... 58

3.10.1. Land Cover Mapping Observations..................................................................................... 58

3.10.2. Baseline Vegetation Assessment.......................................................................................... 60

3.10.3. Invasive Species and Noxious Weeds.................................................................................. 62

3.11. Water Resources........................................................................................................................... 64

3.11.1. Surface Water Resources ..................................................................................................... 64

3.11.2. Groundwater Resources....................................................................................................... 68

3.12. Wetlands and Riparian Zones....................................................................................................... 72

3.12.1. Wetlands............................................................................................................................... 72

3.12.2. Riparian Zones..................................................................................................................... 72

4. Environmental Consequences.......................................................................................................... 73

4.1. Introduction .................................................................................................................................. 73

4.2. Air Quality and Climate Change .................................................................................................. 74

4.2.1. Proposed Action................................................................................................................... 74

4.2.2. No Action Alternative.......................................................................................................... 80

4.3. Cultural Resources ....................................................................................................................... 80

4.3.1. Proposed Action................................................................................................................... 80

4.3.2. No Action Alternative.......................................................................................................... 81

4.4. Fish and Wildlife.......................................................................................................................... 82

4.4.1. Proposed Action................................................................................................................... 82

4.4.2. No Action Alternative.......................................................................................................... 84

4.5. Geology and Minerals.................................................................................................................. 84

4.5.1. Proposed Action................................................................................................................... 84

4.5.2. No Action Alternative.......................................................................................................... 85

4.6. Socioeconomics............................................................................................................................ 85

4.6.1. Proposed Action................................................................................................................... 85

4.6.2. No Action Alternative.......................................................................................................... 87

4.7. Soils.............................................................................................................................................. 87

4.7.1. Proposed Action................................................................................................................... 87

4.7.2. No Action Alternative.......................................................................................................... 89

4.8. Topography and Physiography..................................................................................................... 90

4.8.1. Proposed Action................................................................................................................... 90

4.8.2. No Action Alternative.......................................................................................................... 90

4.9. Vegetation .................................................................................................................................... 90

4.9.1. Proposed Action................................................................................................................... 90

4.9.2. No Action Alternative.......................................................................................................... 92

4.10. Water Resources........................................................................................................................... 92

4.10.1. Proposed Action................................................................................................................... 92

4.10.2. No Action Alternative.......................................................................................................... 94

4.11. Wetlands and Riparian Zones....................................................................................................... 95

4.11.1. Proposed Action................................................................................................................... 95

4.11.2. No Action Alternative.......................................................................................................... 95

5. Cumulative Impacts Analysis.......................................................................................................... 95

5.1. Analysis Areas.............................................................................................................................. 95

5.2. Past, Present, and Reasonably Foreseeable Future Actions......................................................... 97

5.2.1. Past and Present Actions Summary...................................................................................... 97

5.2.2. Reasonably Foreseeable Future Actions Summary.............................................................. 97

5.2.3. Cumulative Impacts by Resource Issue Category................................................................ 98
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6. Mitigation Measures....................................................................................................................... 103

7. Consultation and Coordination ..................................................................................................... 103

7.1. Summary of Public Participation ............................................................................................... 103

7.2. Persons, Groups, and Agencies Consulted................................................................................. 103

7.3. List of Preparers......................................................................................................................... 104

8. Literature Cited .............................................................................................................................. 105

APPENDIX

Appendix A Public Comments on Draft Environmental Assessment and OSMRE’s Responses

FIGURES

Figure 1-1. Project location and surface and underground mining areas.................................................. 2

Figure 2-1. Location of proposed mining in project area. ...................................................................... 12

Figure 2-2. Coal flow diagram................................................................................................................ 21

Figure 3-1. Bridger Mine Complex wind rose (January–December 2015). Source: IML Air 

Science (2015)...................................................................................................................... 30

Figure 3-2. Mule deer habitat in the fish and wildlife impact analysis area. .......................................... 45

Figure 3-3. Elk habitat in the fish and wildlife impact analysis area...................................................... 46

Figure 3-4. Pronghorn antelope habitat in the fish and wildlife impact analysis area............................ 47

Figure 3-5. Stratigraphic column for the mine permit area..................................................................... 51

Figure 3-6. Surface geology in the project area...................................................................................... 52

Figure 3-7. Surface water and groundwater impact analysis areas......................................................... 65
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TABLES

Table 2-1. Acres of Disturbance at the Bridger Mine Complex.............................................................. 8

Table 3-1. Resources Analyzed in Detail and Resources Eliminated from Detailed Analysis ............. 27

Table 3-2. NAAQS and WAAQS.......................................................................................................... 31

Table 3-3. Ambient Air Quality Data in the Analysis Area from 2013 through 2015 .......................... 32

Table 3-4. Bridger Mine Complex 2014 and 2015 Emissions Inventories ........................................... 34

Table 3-5. Bridger Mine Complex 2013–2015 Particulate Concentration Summaries......................... 36

Table 3-6. Jim Bridger Power Plant 2015 Emissions Inventory ........................................................... 38

Table 3-7. Acres of Big-Game Habitat in the Fish and Wildlife Impact Analysis Area ....................... 44

Table 3-8. Migratory Birds with Potential to Occur in or near the Fish and Wildlife Impact 

Analysis Area....................................................................................................................... 48

Table 3-9. Average Thickness of Coal Seams in the Jim Bridger Coal Field ....................................... 53

Table 3-10. Reported Coal Revenues in Wyoming................................................................................. 55

Table 3-11. Inherent Risk of Soil Degradation of the Project Area’s Wint-Westvaco TeagulfTasselman-Rogrube-Huguston-Haterton Soil Complex ...................................................... 57

Table 3-12. Ecological Systems in the Vegetation Analysis Area .......................................................... 58

Table 3-13. Mining Plan Modification Area Absolute Vegetation by Lifeform for Each Range 

Site ....................................................................................................................................... 61

Table 3-14. Mining Plan Modification Area Relative Cover by Lifeform.............................................. 61

Table 3-15. Mining Plan Modification Area Shrub Density by Range Site............................................ 62

Table 3-16. Wyoming Designated Noxious Weeds ................................................................................ 62

Table 3-17. Sweetwater County Declared Weed Species ....................................................................... 63

Table 3-18. Wyoming Department of Environmental Quality Water Quality Division Numeric 

Standards for Class 2AB(ww), Class 2C, and Class 3B Surface Waters............................. 67

Table 4-1. Estimated Emissions Associated with the Burning of Federal Coal from the Project 

Area at the Jim Bridger Power Plant.................................................................................... 75

Table 4-2. Estimated GHG Emissions Associated with Burning of Federal Coal from the Project 

Area...................................................................................................................................... 76

Table 4-3. USGS Climate Change Viewer Projections for Sweetwater County................................... 77

Table 4-4. Sweetwater County Coal Production ................................................................................... 86

Table 4-5. Anticipated Impacts on Ecological Systems in the Analysis Area ...................................... 91

Table 5-1. Cumulative Impacts Analysis Areas by Resource ............................................................... 96

Table 5-2. Big-Game Habitat Acres Affected by the Proposed Action and Percentage of 

Available Acres in the CIAA ............................................................................................. 100

Table 7-1. OSMRE Staff used to Prepare this Environmental Assessment ........................................ 104

Table 7-2. SWCA Environmental Consultants Staff used to prepare this Environmental 

Assessment......................................................................................................................... 104
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Acronyms

μg/g – micrograms per gram

μg/m3 – micrograms per cubic meter

ACEC – Area of Critical Environmental Concern

AIRFA – American Indian Religious Freedom Act of 1978

APLIC – Avian Power Line Interaction Committee

AQRV – air quality related value

ASCM – alternate sediment control measures

ASLM – Assistant Secretary for Land and Minerals Management

BACT – best available current technology

BART – Best Available Retrofit Technology

BCC – Bridger Coal Company

BKS – BKS Environmental Associates, Inc.

BLM – Bureau of Land Management

B.P. – before present

BTU – British thermal unit

CAA – Clean Air Act, as amended

CCW – coal combustion residues or wastes

CEQ – Council on Environmental Quality

CFR – Code of Federal Regulations

CHIA – Cumulative Hydrologic Impact Assessment

CIAA – cumulative impact analysis area

CO – carbon monoxide

CO2 – carbon dioxide

CO2e – carbon dioxide equivalent

DOI – Department of the Interior

EA – environmental assessment

EIS – environmental impact statement 

EPA – U.S. Environmental Protection Agency

ESA – Endangered Species Act of 1973

FCLAA – Federal Coal Leasing Act Amendment of 1976

FGD – flue gas desulphurization

FLPMA – Federal Land Policy and Management Act of 1976

GAP – National Gap Analysis Program
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GHG – greenhouse gas

GIS – geographic information system

gpm – gallons per minute

HAPs – hazardous air pollutants

HUC – Hydrologic Unit Code

kV – kilovolt(s)

lbs – pounds

MACT – Maximum Achievable Control Technology

MBTA – Migratory Bird Treaty Act of 1918, as amended

mg/L = milligrams per liter

MLA – Mineral Leasing Act of 1920

MMPA – Mining and Mineral Policy Act of 1970

MOA – Memorandum of Agreement

MPDD – Mining Plan Decision Document

MSHA – Mine Safety and Health Administration

NAAQS – National Ambient Air Quality Standards

NEPA – National Environmental Policy Act

NESHAPs – National Emissions Standards for Hazardous Air Pollutants

NHPA – National Historic Preservation Act, as amended

N2O – nitrous oxide

NO2 – nitrogen dioxide

NOX – nitrogen oxides

NRCS – Natural Resources Conservation Service

NRHP – National Register of Historic Places

NSPS – New Source Performance Standards

NWI – National Wetlands Inventory

O3 – ozone

OSMRE – Office of Surface Reclamation and Enforcement

PAP – Permit Application Package

PM – particulate matter

PSD – Prevention of Significant Deterioration

R2P2 – Resource Recovery and Protection Plan

RFFAs – reasonably foreseeable future actions

SCC – social cost of carbon

SDWA – Safe Drinking Water Act, as amended
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SEDCO – sediment control monitoring network

SMCRA – Surface Mining Control and Reclamation Act of 1977

SO2 – sulfur dioxide

SPCC – spill prevention, control, and countermeasure

TDS – total dissolved solids

TSS – total suspended solids

USFWS – U.S. Fish and Wildlife Service

USGS – U.S. Geological Survey

VOC – volatile organic compound

WAAQS – Wyoming Ambient Air Quality Standards

WAS – Western Archaeological Services

WDEQ – Wyoming Department of Environmental Quality

WDEQ-AQD – Wyoming Department of Environmental Quality, Air Quality Division

WDEQ-LQD – Wyoming Department of Environmental Quality, Land Quality Division

WDEQ-WQD – Wyoming Department of Environmental Quality, Water Quality Division

WDWS – Wyoming Department of Workforce Services

WGFD – Wyoming Game and Fish Department

WWPC – Wyoming Weed and Pest Council
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Jim Bridger Coal Mine Complex Mining Plan Modification for Federal Coal Lease WYW02727 

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1. PURPOSE AND NEED

1.1. Introduction

The Environmental Assessment for Jim Bridger Coal Mine Complex Mining Plan Modification for 

Federal Coal Lease WYW02727 has been prepared by the Office of Surface Reclamation and 

Enforcement (OSMRE), Western Region. Since 1974, in accordance with the Mineral Leasing Act of 

1920 (MLA) and the federal mining plan approved by the Assistant Secretary for Land and Minerals 

Management (ASLM), the operator of the Bridger Mine Complex (currently Bridger Coal Company 

[BCC]) has mined portions of federal coal lease WYW02727, in accordance with the approved surface 

coal mining permit issued by the state regulatory authority, the Wyoming Department of Environmental 

Quality, Land Quality Division (WDEQ-LQD). On November 28, 2014, in accordance with its 

responsibilities under the Federal Surface Mining Control and Reclamation Act of 1977, the WDEQ-LQD 

approved the Amendment and Mine and Reclamation Plan Revision for surface coal mining Permit No. 

338-T7, including the mining of portions of federal coal lease WYW02727 not previously approved by 

the ASLM. In accordance with the MLA, the ASLM must approve the mining plan modification for 

federal coal lease WYW02727 before mining of the federal coal can occur. 

OSMRE prepared this environmental assessment (EA) to evaluate and disclose the potential for direct, 

indirect, and cumulative impacts to the environment from current and future mining operations at the 

Bridger Mine Complex from 2016 through the life of the mine within the portions of federal coal lease 

WYW02727 that lie within the approved Surface Mining Control and Reclamation Act of 1977 

(SMCRA) permit area; mining operations in this area is hereafter referred to as the project (Figure 1-1).

The EA review has been conducted in accordance with the National Environmental Policy Act (NEPA)

and with the Council on Environmental Quality (CEQ) regulations for implementing NEPA (40 Code of 

Federal Regulations [CFR] 1500-1508); the Department of the Interior’s (DOI’s) regulations for 

implementation of NEPA (43 CFR 46); the DOI’s Departmental Manual Part 516; and OSMRE’s 

Directive REG-1, Handbook on Procedures for Implementing the National Environmental Policy Act 

(OSMRE 1989). Information gathered from federal, state, and local agencies; BCC; publicly available 

literature; and in-house OSMRE sources, such as the Bridger Mine Complex Permit Application Package 

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

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” 

affect the environment. The term “significantly” is defined in 40 CFR 1508.27. If OSMRE determines, 

based on the analysis in the EA, that the proposed mining plan modification would have significant 

impacts, an environmental impact statement (EIS) would be prepared for the proposed mining plan 

modification. If OSMRE determines that the potential impacts would not be significant, OSMRE would 

prepare a finding of no significant impact to document this finding, and, accordingly, would not prepare 

an EIS. 
Jim Bridger Coal Mine Complex Mining Plan Modification for Federal Coal Lease WYW02727 

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Figure 1-1. Project location and surface and underground mining areas.
Jim Bridger Coal Mine Complex Mining Plan Modification for Federal Coal Lease WYW02727 

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The Bureau of Land Management (BLM) completed an EA in 2010 that analyzed the modification of 

BCC’s coal lease WYW02727 (referred to hereafter as the “2010 Bridger Lease Modification EA”) (BLM 

2010). OSMRE was a cooperating agency on the 2010 Bridger Lease Modification EA. The proposed 

action analyzed in the 2010 Bridger Lease Modification EA was the modification of coal lease 

WYW02727 to include parcels of unleased coal lands situated within Sections 12 and 24, Township 20 

North, Range 100 West, and to obtain a right-of-way to conduct surface operations in Section 36, 

Township 20 North, Range 100 West. The mining plan modification area is 560 acres in total and would 

result in approximately 104 acres of surface disturbance from surface mining activities. The 2010 Bridger 

Lease Modification EA analyzed potential impacts to air quality and climate change, cultural resources, 

grazing, riparian wetlands, water depletion, and wildlife. The analysis in this EA tiers to the analysis in 

the 2010 Bridger Lease Modification EA where appropriate. This EA only addresses the mining plan 

modification associated with the modification of lease WYW02727 and does not address the right-of-way 

in Section 36. The indirect effects of coal combustion at the Jim Bridger Power Plant are analyzed in this 

EA, but the Jim Bridger Power Plant is not considered a connected action in the EA because the power 

plant would operate whether or not the Proposed Action is approved and because the Proposed Action 

would not automatically trigger any action at the Jim Bridger Power Plant that would require an EIS, 

permit modification, or other changes.

1.2. Background

The Bridger Mine Complex is operated by BCC and is located approximately 31 miles northeast of Rock 

Springs, Wyoming (see Figure 1-1). The Bridger Mine Complex consists of a multi-faceted mining 

operation inclusive of surface, underground, and highwall mining methods, together with ongoing 

reclamation operations. The mine produces coal from federal, private, and state lands situated within the 

area known as the Union Pacific Railroad checkerboard land grant. Union Pacific lands are now owned 

and controlled by Anadarko Petroleum Corporation. BCC is a joint venture by two owners: Idaho Energy 

Resource Company, a wholly owned subsidiary of Idaho Power Company, and Pacific Minerals, Inc., a 

wholly owned subsidiary of PacifiCorp. The Bridger Mine Complex produces between 3.7 and 6.5

million tons of coal per year (1.5–3.0 million tons of coal from the underground operation and 2.2–3.5

million tons from the surface operation). The Bridger Mine Complex currently provides most of the coal 

requirements for the adjacent Jim Bridger Power Plant.

With the potential expansion for surface strip-mine development in the southern Bridger coal field, it 

becomes necessary to secure 560 acres of federal coal lands to accommodate the expanded mine recovery 

area. The 560 acres of federal coal lands contain 4.5 million tons of recoverable coal (199,979 tons in 

Section 12 and 4.3 million tons in Section 24). This mining plan modification would allow approximately 

700,000 tons of federal coal per year to be surface-mined on average, extending the life of the mine by 

approximately 13 years when combined with future mining on adjacent private lands, from 2025 to 2037. 

The average annual production of coal mined directly from the 560 acres of federal coal lands would be 

214,286 tons. The estimate for recoverable reserves was predicated on several factors, including inherent 

geologic and mining conditions, coal quality, mine economics, marketability, environmental concerns,

and safety. The inclusion of these lease modification parcels into the existing Bridger Mine Complex 

surface coal mine operation is the only economical and technologically feasible means of recovering these 

portions of coal reserves, which otherwise would be subjected to bypass. The coal reserves contained 

within the lease tract would be mined, delivered, and utilized for the generation of electricity. The surface 

mine expansion in the mining plan modification area forms a logical contiguous reserve.

Four federal leases are included in the Bridger Mine Complex. The BLM issued lease WYW0313558 to 

BCC in January 1968. The BLM issued leases WYW02728 and WYW0207 to BCC in October 1969. The 

BLM issued lease WYW154595 to BCC for the underground mine in March 2005. The BLM modified 
Jim Bridger Coal Mine Complex Mining Plan Modification for Federal Coal Lease WYW02727 

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lease WYW02727 to add 560 acres in July 2010, following completion of the 2010 Bridger Lease 

Modification EA. The BLM modified lease WYW154595 to add approximately 320 acres to the 

underground mine in May 2013, following completion of the 2013 Bridger Lease Modification EA. A 

second BLM modified lease WYW154595 is pending in 2017, to add approximately 120 acres. BCC now 

seeks federal approval of its State of Wyoming approved revised mine permit to account for the 560 new 

acres added to lease WYW02727.

Four State of Wyoming leases are included in the project. The State of Wyoming issued lease 0-40779 

(1,280 acres) to BCC in April 2001, issued lease 0-26745 (1,280 acres) to BCC in January 1995, issued 

lease 0-40333 to BCC in June 2001, and issued lease 0-42077 (640 acres) to BCC in February 2007.

BCC acquired the Union Pacific Railroad coal lease in January 1969, for private coal adjacent to the 

federal coal leases. Union Pacific coal leases were later converted to Anadarko coal leases. The Anadarko 

coal lease for the underground mine was obtained in December 2003. The Anadarko coal leases 

applicable to the current federal mining plan modification area were obtained in June 2012 and April 

2014.

The total acreage covered by BCC’s existing mine permit is 28,513.71 acres. The total acreage of 

completed mining and reclamation in the permit area is 4,491.8 acres. The total acreage of existing 

surface mining operations in the permit area is 6,151.4 acres. Upon completion of mining, approximately 

11,368 acres will have been disturbed and reclaimed. The proposed mining plan modification area would 

add 104 acres of mining and reclamation to the permit area.

1.2.1. Statutory and Regulatory Background

For existing approved federal mining plans that are proposed to be modified, OSMRE prepares a Mining 

Plan Decision Document (MPDD) for a federal mining plan modification. The ASLM reviews the MPDD 

and decides whether or not to approve the federal mining plan modification and, if the modification is

approved, what, if any, conditions may be needed. OSMRE’s recommendation regarding the evaluation 

of the federal mining plan modification will be based, at a minimum, on the following:

1. The Permit Application Package (PAP)

2. The Resource Recovery and Protection Plan (R2P2)

3. Information prepared in compliance with NEPA, including this EA

4. Documentation demonstrating compliance with the applicable requirements of federal laws, 

regulations, and executive orders other than NEPA

5. Comments and recommendations or concurrence of other federal agencies and the public

6. Findings, recommendations, and contractual commitments and requirements of the BLM with 

respect to lease WYW02727, the R2P2, and the MLA

7. Findings and recommendations of the WDEQ-LQD with respect to the mine permit revision 

application

8. The findings and recommendations of OSMRE with respect to the additional requirements of 30 

CFR Chapter VII, Subchapter D (30 CFR 740–746)

1.3. Purpose and Need

The purpose of the Proposed Action is established by the MLA and the SMCRA, which requires the 

evaluation of BCC’s proposed mining plan modification for the Bridger Mine Complex before conducting 

surface mining and reclamation operations to develop federal coal under lands within the lease 
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WYW02727 area. OSMRE is the agency responsible for making a recommendation to the ASLM to 

approve, disapprove, or approve with conditions the proposed mining plan modification. The ASLM will 

decide whether the mining plan modification is approved, disapproved, or approved with conditions.

The need for the action is to provide BCC the opportunity to exercise its valid existing rights granted by 

the BLM under federal coal lease WYW02727 to access and mine undeveloped resources located 

adjacent to the existing Bridger Mine Complex. The need for the action is also established by the ASLM 

responsibility under the MLA of 1920 and the SMCRA of 1977, as amended. Part of OSMRE's 

responsibility, as stated in the SMCRA Public Law 95-87, Title I, Section 102, is to “assure that the coal 

supply essential to the Nation’s energy requirements, and to its economic and social well-being is 

provided and strike a balance between protection of the environment and agricultural productivity and the 

Nation’s need for coal as an essential source of energy.”

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:

1. MLA

2. NEPA

3. SMCRA

4. Federal Coal Leasing Act Amendment of 1976 (FCLAA)

5. Federal Land Policy and Management Act of 1976 (FLPMA)

6. Multiple-Use Sustained Yield Act of 1960

7. Endangered Species Act of 1973 (ESA)

8. Clean Air Act, as amended (CAA)

9. Safe Drinking Water Act, as amended (SDWA)

10. National Historic Preservation Act, as amended (NHPA)

11. American Indian Religious Freedom Act of 1978 (AIRFA)

12. Migratory Bird Treaty Act of 1918, as amended (MBTA)

13. Mining and Mineral Policy Act of 1970 (MMPA)

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

resources. The BLM is the federal agency that has been 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, the BLM complies with FLPMA to plan for multiple uses of public lands and to determine 

those lands suitable and available for coal leasing and development. Through preparation of land use plans 

and/or in response to coal industry proposals to lease federal coal, the 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 
Jim Bridger Coal Mine Complex Mining Plan Modification for Federal Coal Lease WYW02727 

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resources. The BLM then makes the lands that are determined suitable for coal development available for 

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

of federal coal. Once a lease is issued, the 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. The 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 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 pre-mine conditions or better 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 Mineral Resources, Chapter VII – OSMRE, DOI (30 

CFR 700–end). 

As provided for under SMCRA, OSMRE works with coal-producing states and tribes to develop their 

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

tribe, OSMRE steps into an oversight role. OSMRE approved the State of Wyoming’s coal regulatory 

program on November 26, 1980 (30 CFR 950.10). As a result, Wyoming manages its own program under 

the WDEQ-LQD’s Coal Rules and Regulations. WDEQ-LQD has the authority and responsibility to 

make decisions to approve surface coal mining permits and regulate coal mining in Wyoming under its 

Coal Rules and Regulations with oversight from OSMRE. The cooperative agreement between OSMRE 

and WDEQ-LQD allows the WDEQ-LQD to regulate surface coal mining on federal lands or leases while 

OSMRE continues to carry out its obligations under the MLA, NEPA, and other public laws (30 CFR 

950.20), which includes the recommendations related to mining plans and mining plan modifications. 

1.4.2. Other Agency Plans 

The BLM’s Record of Decision and Green River Resource Management Plan (BLM 1997), effective as 

of 1997, allows for coal leasing and development and provides land use guidance for coal leasing within 

the proposed project area. Decisions pertaining to this proposal include the following: 

Solid Leasables (Coal) 

o The objective for management of the federal coal resources in the planning area is to 

provide for both short- and long-range development of federal coal, in an orderly and 

timely manner, consistent with the policies of the federal coal management program, 

environmental integrity, national energy needs, and related demands.

o With appropriate limitations and mitigation requirements for the protection of other 

resource values, all BLM-administered public lands and Federal coal lands in the Green 

River planning area, except for those lands identified as closed, are open to coal resource 

inventory and exploration to help identify coal resources and their development potential. 

(BLM 1997:13) 

Land and Realty Management

o Manage public lands to support the goals and objectives of other resource programs; 

o Respond to public demand for land use authorizations; and 

o Acquire administrative and public access where necessary. (BLM 1997:9) 

The Sweetwater County Comprehensive Plan addresses the County’s present and future land use needs 

and development objectives (Sweetwater County 2002). The Sweetwater County Growth Management 
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Plan and Agreement includes a Master Transportation Plan (Sweetwater County 2011). The Master 

Transportation Plan establishes standards and rules for the development and management of 

transportation corridors, streets, and roadways. Any OSMRE decisions pertaining to this proposal would 

take into account the Sweetwater County Comprehensive Plan and Master Transportation Plan. 

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 permit approved by the regulatory authority, in this case 

WDEQ-LQD, and 2) a mining plan or mining plan modification approved by the ASLM in accordance 

with the MLA.

1.6. Scoping, Outreach, and Issues Identification 

In advance of preparing this EA, public comments were solicited through several methods. OSMRE 

published a legal notice in The Rocket-Miner on June 1, 2016. The legal notice summarized the proposed 

mining plan modification and informed the public that comments would be accepted until July 1, 2016. 

An outreach letter describing the proposed mining plan modification and soliciting comments was mailed 

on June 1, 2016, to a total of 126 recipients, including city governments, adjacent landowners, and other 

interested parties. Also on June 1, 2016, five letters were sent to American Indian tribes.

In all, nine letters were received during the public comment period. These comments were evaluated for 

relevance in preparing this EA. Letters expressing concerns or suggestions regarding the Proposed Action 

were received from state and local government entities, such as chambers of commerce, the Rock Springs 

City Council, Sweetwater County, and the Wyoming Game and Fish Department (WGFD). Letters were 

also received from the Sierra Club and Wild Earth Guardians. One individual submitted a letter in support 

of the Proposed Action. Local government entities were generally in support of the Proposed Action 

because of its potential economic benefits. The WGFD noted that the project area lies within a sagegrouse core area and that any surface disturbance is potentially subject to a density/disturbance 

calculation tool process. The WGFD also suggested reclamation practices for the sage-grouse core area. 

The Sierra Club and Wild Earth Guardians both requested analysis of specific potential impacts of the 

Proposed Action, such as the continued combustion of coal at the Jim Bridger Power Plant, climate 

change impacts, cumulative impacts of surface and underground mining, subsidence impacts, fugitive 

dust impacts, air quality impacts, wildlife impacts, and water resources impacts. The Sierra Club and 

Wild Earth Guardians also requested that an EIS be prepared rather than an EA. Wild Earth Guardians 

requested that a larger range of alternatives be analyzed, and they suggested five new alternatives that 

would limit the mining levels, reduce emissions, use renewable sources of energy, and require off-site 

mitigation. A summary of the issues raised in the public scoping comments is on file with OSMRE.

Appendix A includes the comments received on the Draft EA and OSMRE’s responses to those 

comments.

2. PROPOSED ACTION AND ALTERNATIVES

2.1. Introduction

Under NEPA requirements, the agency must evaluate the environmental impacts of a reasonable range of 

alternatives. The DOI’s NEPA implementing regulations define reasonable alternatives as those that are 

“technically and economically practicable or feasible and meet the purpose and need of the proposed 
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action” (43 CFR 46.420). This chapter describes Alternative A (No Action Alternative) and Alternative B 

(Proposed Action), which are considered and analyzed in detail in this EA, and provides information on 

the existing operations at the Bridger Mine Complex and how those operations may change under the 

Proposed Action. In addition, it identifies alternatives considered but eliminated from detailed analysis.

2.1.1. Existing Operations at Bridger Mine Complex 

Since 1974, BCC has mined portions of federal coal lease WYW02727 in accordance with the approved 

surface coal mining permit issued by the state regulatory authority, the WDEQ-LQD. On November 28, 

2014, in accordance with its responsibilities under the Federal Surface Mining and Reclamation Control 

Act of 1977, the WDEQ-LQD approved the Amendment and Mine and Reclamation Plan Revision for 

surface coal mining permit no. 338-T7, including the mining of portions of federal coal lease WYW02727 

not previously approved by the ASLM. In accordance with the MLA, the ASLM must approve the mining 

plan modification for federal coal lease WYW02727 before mining of the federal coal can occur. 

BCC currently has approximately 28,500 permitted acres in Sweetwater County, Wyoming. Upon 

completion of mining, approximately 11,368 acres will have been disturbed and reclaimed. Total 

disturbance from mining activities at the Bridger Mine Complex from 1986 to 2016 is estimated to be 

10,690 acres. The existing mine facilities total approximately 10,580 acres of surface disturbance, which 

includes structures, roads, ponds, pits, and all other mine-related disturbance. Table 2-1 lists the total 

acres of disturbance from mining and mine facilities for each year beginning in 1986. 

Table 2-1. Acres of Disturbance at the Bridger Mine Complex

Year Estimated Disturbed Area 

(acres)

Cumulative Disturbed Area 

(acres)

Inception: 1986 4,285 4,285

1987 177 4,462

1988 313 4,775

1989 400 5,175

1990 126 5,301

1991 149 5,450

1992 194 5,644

1993 415 6,059

1994 537 6,596

1995 357 6,953

1996 175 7,128

1997 313 7,441

1998 351 7,792

1999 481 8,273

2000 575 8,848

2001 64 8,912

2002 212 9,124

2003 236 9,360

2004 152 9,512
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Year Estimated Disturbed Area 

(acres)

Cumulative Disturbed Area 

(acres)

2005 186 9,698

2006 −47* 9,651

2007 102 9,753

2008 91 9,844

2009 95 9,939

2010 115 10,054

2011 350 10,404

2012 90 10,494

2013 52 10,546

2014 71 10,617

2015 44 10,661

2016 29 10,690

Note: Data from 2013–2016 are projections. 

*A reassessment of the total acres of disturbed areas resulted in an adjustment between the acres disturbed to date as of December 2005 and 

December 2006. 

2.1.1.1. MINING METHODS

Within the surface mining portion of the Bridger Mine Complex, stripping is presently being done from 

the Central Mine Area to the Tenmile South Area. The final highwall has been reached in Deadman North 

Area, highwall mining has been completed there, and underground mining is in progress. The Tenmile 

South Area was linearly extended to its southernmost limit by the end of 2000. Dragline stripping is 

currently supported by truck-loader pre-stripping in areas of thick overburden. 

The underground mining layout and sequence at the Bridger Mine Complex is an arrangement of 

longwall panels and development sections interconnected by systems of main and sub-main entries. The 

underground mine is developed by continuous miners with mains and gate road entries that support a 

series of longwall mining panels. Mining takes place within the D41 seam, which is found to dip 2 to 5 

degrees to the northeast and which is covered with overburden ranging from 200 feet to 1,000 feet over 

the mining area. Access to the underground mine is through a series of three portals located at the base of 

the highwall. Main entries are driven into the deposit to develop the mine for longwall mining type of 

coal extraction.

Overburden, interburden, and coal are blasted as necessary before removal. BCC’s blasting program 

applies to surface mining, highwall mining, and underground mining. BCC complies with all applicable 

state, federal, and local laws regarding the handling, preparation, and use of explosives, and BCC’s 

mining plan contains a detailed blasting plan. BCC provides a pre-blasting survey to any residents or 

owners of buildings located within 0.5 mile of the permit area upon request. The blasting schedule for the 

Bridger Mine Complex is published annually in the local newspaper in Rock Springs, Wyoming, and 

distributed to applicable government entities and utilities providers. Notice is published between 30 and 

60 days before a blasting program begins. 

2.1.1.2. TOPSOIL 

Soil removal occurs prior to mining disturbance and prevents contamination of soil resources by 

potentially unsuitable material. Salvage depths are based on soil survey and site evaluation. Removal is 
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accomplished with scrapers or with a dozer-loader-truck combination. Qualified reclamation personnel 

using baseline soil maps supervise the fleet. All suitable soils are salvaged. When feasible, the top 6 

inches of soil is handled separately.

Whenever practical, soil is salvaged and applied directly to regraded soil. However, when field conditions 

preclude this opportunity or when the amount of soil being salvaged is greater than the amount needed for 

application, soil is stored in stockpiles located within the permit area.

Soil stockpiles are protected from wind and water erosion and clearly marked with signs. Stockpiles are 

located so they are out of operational pathways, are oriented to minimize erosion, and are out of natural 

drainages.

2.1.1.3. TEMPORARY OVERBURDEN STOCKPILE

Temporary out-of-pit overburden stockpiles may be constructed on the highwall or lowwall sides of the 

pit, as necessary. Approved out-of-pit spoils have occurred as a result of boxcut pits south of Nine and 

One-Half Mile Draw and Tenmile Draw. Boxcut spoils or spoil piles will not be placed on slopes greater 

than 20 degrees or in drainages. The permanent out-of-pit spoil material is designed and constructed to 

blend into the native topography to achieve approximate original contour in conformance with WDEQLQD Coal Rules and Regulations, Chapter 4, Section 2(c)(xi). 

2.1.1.4. ACCESS AND HAUL ROADS 

Roads currently provide the primary means of transport for personnel and materials within the Bridger 

Mine Complex. Roads are also the means of transport of coal from the pit to the conveyor truck dump 

hoppers and as a contingency for coal haulage to the power plant in the event of conveyor system failure. 

The roads are separated into two main categories: primary roads and ancillary roads. 

Primary roads are defined as 

surface corridor(s) of affected land associated with travel by land vehicles used in surface coal 

mining and reclamation operations or coal exploration. A road consists of the roadbed, shoulders, 

parking and side areas, approaches, structures, ditches, and surface. The term includes access and 

haul roads constructed, reconstructed, improved, or maintained for use in surface coal mining and 

reclamation operations or coal exploration, including use by coal hauling vehicles to and from the 

transfer, processing, or storage areas. The term does not include ramps and routes of travel within 

the immediate mining area or within spoil or coal mine waste disposal areas. The term immediate 

mining area refers to areas subjected to frequent surface changes. This includes areas where 

topsoil and overburden are being moved. (WDEQ-LQD, Coal Rules and Regulations, Chapter 1, 

Section 2(ds)) 

All of BCC’s primary roads have designed surfaces, grades, shoulders, and drainage control structures. 

Additional primary roads may be constructed throughout the mine life to facilitate coal haulage.

An ancillary road is any road not classified as a primary road. Most of the ancillary roads in the Bridger 

Mine Complex are roads in the pit. These roads are reclaimed simultaneously with the pit. Other roads in 

the Bridger Mine Complex that are classified as ancillary include roads to several air quality sites and soil 

stockpiles and roads along power lines. Although these types of roads are unchanging in some cases for 

the life of the mine, they are lightly used roads typically built on the land surface following the removal of 

topsoil. These roads follow the land surface profile and do not have any road surfacing.

There are approximately 19 miles of haul roads and 1.5 miles of county roads in the existing Bridger 

Mine Complex mine permit boundary. 
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2.1.1.5. POWER LINES

Electrical power is provided to the Bridger Mine Complex from the Jim Bridger Power Plant located 

adjacent to the mine site. There are approximately 54 miles of power lines in the existing Bridger Mine 

Complex mine permit boundary (Figure 2-1). Design of all existing electrical distribution lines conforms 

to the Avian Power Line Interaction Committee’s (APLIC’s) Suggested Practices for Raptor Protection 

on Power Lines: The State of the Art in 1996 (APLIC et al. 1996). If new information on best available 

current technology (BACT) for improved electrocution protection becomes available, it would be used to 

update power line designs as necessary to prevent raptor electrocution. Minor modifications to power 

lines may be required during the life of the surface mine.

2.1.1.6. MINE FACILITIES

Buildings are located in three areas: the general office area, the erection lot, and the underground mine 

facility area. The first area includes the main office, the shop and warehouse building, and the gasoline 

shop. The erection lot includes a field maintenance shop, tire shop, electrical shop, cable rebuild shop, 

and several small storage trailers and sheds. The underground mine facility area includes an office and 

bathhouse, warehouse and shop building, parking, material storage, and other associated structures. 

Facilities for storing explosives used for blasting are located away from offices and warehouse facilities. 

Explosive storage facilities comply with applicable requirements of the Bureau of Alcohol, Tobacco and 

Firearms as administered by the Mine Safety and Health Administration (MSHA) and other applicable 

MSHA requirements. Other storage facilities include aboveground storage tanks, soil stockpiles, 

overburden stockpiles, coal stockpiles, ponds, and one active solid waste disposal site. There are 

approximately 3.8 acres of buildings and storage tanks in the existing Bridger Mine Complex mine permit 

boundary (see Figure 2-1).

2.1.1.7. PONDS, IMPOUNDMENTS, DIVERSIONS

Ponds are used for two separate functions at the Bridger Mine Complex. First, holding ponds treat pit 

water before it is discharged into adjacent ephemeral streams. Treatment refers primarily to the settling of 

sediment particles, although other treatments may also be necessary. Second, sediment ponds are used to 

collect surface runoff from facilities and coal storage areas. The majority of sediment ponds that treat 

runoff from mine disturbance have been replaced by alternate sediment control practices. However, 

sediment ponds still exist at facilities areas where point source discharges occur. There are approximately 

2.5 acres of ponds in the existing Bridger Mine Complex mine permit boundary (see Figure 2-1). 

2.1.1.8. WATER SOURCE

BCC’s domestic water is supplied from four sources: a well registered to Pacific Power & Light 

Company, the Bridger No. 1 well, the Green River pipeline system, and bottled water. Potable water is 

used at the Bridger Mine Complex for drinking and showers (1.75 million gallons per year). Non-potable 

water is obtained from pumping water out of pits into holding ponds on an as-needed basis, as well as 

pumping water from overburden dewatering wells on the existing permit area and used for dust 

suppression (between 70 million and 170 million gallons per year), washing equipment (approximately 1 

million gallons per year), fire prevention, and other related uses. There are approximately 11 miles of 

water lines in the existing Bridger Mine Complex mine permit boundary (see Figure 2-1). None of these 

water lines are within the area of proposed mining.
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Figure 2-1. Location of proposed mining in project area.
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BCC has secured an agreement with Pacific Power & Light Company for the domestic and non-potable 

water used by the BCC surface mine office and shop facilities. The appropriation for the water is held by 

Pacific Power & Light Company. BCC has been designated as a user.

BCC’s underground facilities are supplied by the Bridger No. 1 well, which is 3,100 feet deep and 

completed in the Ericson Formation. This well pumps to a storage tank that provides the pressure for the 

uses of the water. Underground facilities, including the mine operations, are estimated to require 200 

gallons per minute (gpm), or 105 million gallons per year, on the average. The peak usage of water is 

estimated to be 400 gpm. The usage of potable water for drinking, showers, and washing equipment is a 

small portion of the total usage and is estimated at approximately 2 million gallons per year.

2.1.1.9. OPEN PITS

The initial cut or boxcut in a panel starts along the strike of a coal seam and is irregular in shape and 

width. At low overburden depths, the draglines normally work in a side-casting mode to strip the 

overburden. The overburden is excavated and placed in a previously excavated pit. When the overburden 

depth becomes great enough, the simple side-casting mode becomes impractical because the previous pit 

will no longer allow sufficient room for the spoil material at the effective spoil radius of the dragline.

As stripping depths increase, other procedures are employed, such as two-pass or pull-back methods. In 

the two-pass method, a pad is formed in the previous pit for positioning the dragline for the next lift in the 

pit. Placing the dragline on the pad allows the machine to dig to a greater depth while still maintaining 

spoil room. When overburden to be stripped is beyond the capacity of the dragline to spoil off the coal by 

any other methods, the pull-back method can be used. In this method, a secondary dragline can be placed 

on the spoil bank to pull back sufficient spoil to make room for complete removal of overburden. 

At varying times during the life of the mine, it has been necessary to place spoil material outside of the 

active mining area. Due to the operating constraints of the dragline, it is necessary for spoil material to be 

permanently placed outside of the pit when new pit areas are being developed. The spoil material that is 

permanently placed outside of the pit would be blended to meet post-mining requirements. 

BCC currently operates a backhoe and front-end loaders as primary coal loading units. Changes to the 

equipment type and use may occur as BCC constantly evaluates and updates the equipment requirements 

for the Bridger Mine Complex. 

2.1.1.10. HAZARDOUS MATERIALS

Mine equipment operating at the Bridger Mine Complex uses diesel fuel, unleaded gasoline, engine oils, 

gearbox oils, open gear greases, and glycols. Solvents are used for parts cleaning during major equipment 

maintenance outages. All used lubricants, glycols, and solvents are collected in drums or small storage 

tanks with appropriate waste category labels and stored at a waste and used lubricant storage area. The 

Bridger Mine Complex has a waste minimization program and the mine is a conditionally exempt small 

quantity generator. Most waste chemical or lubricant is solid, non-hazardous waste that is recycled. 

Unleaded gasoline and diesel fuels are stored and dispensed at designated fuel islands with secondary 

containment to meet spill prevention, control, and countermeasure (SPCC) requirements.

2.1.1.11. MINE PERSONNEL

The Bridger Mine Complex operates 24 hours per day, 7 days a week, and employs approximately 

510 people. 
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2.1.1.12. TRANSPORTATION

No rail transport is currently used at the Bridger Mine Complex. All transport of coal is accomplished 

using haul trucks and an overland conveyor. The overland conveyor transports coal from the Bridger 

Mine Complex to the Jim Bridger Power Plant. No public roads are used to transport coal from the 

Bridger Mine Complex to the Jim Bridger Power Plant. Additional facilities associated with the conveyor 

include power lines, wildlife crossings, hydrologic control structures, and dust control equipment. 

2.1.1.13. RECLAMATION

Reclamation is an ongoing process at the Bridger Mine Complex. The reclamation schedule is dependent 

on the mining plan and the mining sequence. The surface mine has multiple seams at various thickness 

and quality scheduled to be mined. Mine sequencing is dependent on the depth of overburden, length of 

pit, and coal blending requirements. BCC will normally leave four spoil peaks between the regraded area 

and the pit, which generally requires that 2 or 3 years lead time precede final grading. This helps to 

protect reclaimed areas from blasting, spoiling, and other mining operations (BCC 2009). 

Following regrading of the spoil materials, topsoil will be applied. Topsoil is usually removed from a 

stockpile and applied on regraded spoil. When possible, topsoil will be direct hauled from new soil 

stripping areas and immediately applied on regraded spoil. Newly applied topsoil will normally be 

revegetated ahead of the next growing season. Revegetation is done with a mixture of mostly native 

grasses, forbs, and shrubs. Seed mixes contain high species diversity. Revegetation techniques are 

designed to minimize erosion (BCC 2009). In general, topsoil replacement will occur in the spring 

through fall, and final seeding will occur in the fall.

The objective for reclaiming disturbed land in the mine area is to restore the land to its pre-mine use of 

wildlife and domestic livestock habitat and forage, respectively. No portions of the reclaimed site would 

be managed exclusively for either domestic livestock or wildlife species. Rather, the entire area would be 

returned to an undeveloped rangeland status, equal to or better than its pre-mining condition, capable of 

supporting both domestic livestock and wildlife species. A vegetation monitoring program is conducted 

over the life of the mine to aid in determining when the post-mining land use of undeveloped rangeland is 

met.

An objective of reclamation at the Bridger Mine Complex is to recreate wildlife habitats on postreclamation acreages. Because of their pre-mining prevalence and specific winter browse requirements, 

pronghorn are receiving special consideration in reclamation planning. Greater sage-grouse also receive 

special consideration in reclamation planning.

The objective of the post-reclamation surface recontouring effort is to:

1. Leave the majority of slopes less than or equal to 4 horizontal to 1 vertical, with the exception of 

the mine area that was disturbed prior to May 3, 1978, and areas where bluffs are to be 

constructed, 

2. Provide drainage to all areas, and

3. Ensure that the reclaimed surface will support the post-mining land use. 

2.1.1.13.1. Backfilling and Grading

Contemporaneous reclamation is normally done to within 1,000 feet from the active pit centerline 

wherever practical. The backfill volume is large because drainages are reconstructed perpendicular to the 

highwall. The 1,000-foot distance account for the volume of spoil that is required to backfill the final pit. 
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Otherwise, excess material will have to be taken from additional back-sloping of the highwall, which will

increase disturbed area. Spoils adjacent to the ramps will remain unreclaimed until that area reaches its 

final pit limits and the spoil will be utilized for ramp closure.

As mining is concluded in each area, a determination would be made on the feasibility of highwall 

mining, and rough grading would occur as quickly as equipment capacity and practicality allow. Final 

grading is defined as grading the surface to the approved post-reclamation contour or post-mining 

topography. Once this topography has been achieved, and approval has been received from the State for 

application of topsoil, ripping of the surface occurs in preparation for soil application. When doing 

contemporaneous reclamation, this process occurs between 1,000 and 1,500 feet from the pit centerline, 

except along ramp access points and other areas required for supplying material to the final pit.

Highwall mining could potentially occur along most of the final highwall of the mine. As mining reaches 

each of these final highwalls, an evaluation would be conducted to determine whether it would be feasible 

to recover additional coal from the areas beyond this mining highwall limit. After this determination is 

made, the coal would either be recovered or remain in the ground, and the final pit would be graded as 

soon as equipment capacity and practicality allow. At times, this requires extended grading time due to 

the large volumes of material required to fill the final pit to approved contours. Material required to 

backfill the final pit is obtained by lowering the slope of the final highwall and by widening the drainage 

basin on the lowwall site of the final pit.

Final grading and soil application for all areas except those reserved for filling the final pits and ramps 

follows rough grading as soon as practicable. Constraints in this activity include availability of material 

for direct application. Time between rough grading, final grading, and soil application operations is 

necessary to allow time to sample soils, provide 4 feet of suitable cover if necessary, and complete soil 

replacement operations. Seeding begins in the fall or in early spring following the application of soil.

BCC would minimize disturbed areas consistent with good mining practices and coal production 

requirements. Additionally, the reclamation bond would continue to be maintained in an amount adequate 

to reclaim the disturbance existing or projected during the term of the bond. BCC anticipates that all areas 

would be ready for bond release approximately 15 years following final mining. 

2.1.1.13.2. Revegetation

Post-reclamation vegetation at the Bridger Mine Complex would reestablish the land use as undeveloped 

rangeland. A vegetation monitoring program would be conducted over the life of the mine to aid in 

determining when that objective is met.

A diverse, effective, and permanent vegetation cover would be established on lands disturbed by mining 

operations. Species selected for revegetation would be adapted to climatic and edaphic conditions. In 

accordance with the post-reclamation land use, which includes both domestic livestock grazing and 

wildlife habitat, BCC would reestablish major species of graminoids, forbs, and shrubs. 

Loamy/Shallow Loamy and Saline Upland range sites are dominant in the permit area, with soils in 

Sections 12 and 24 that are generally sandy loam, loamy sand, loam, or silty loam in texture. Thus, 

Loamy/Shallow Loamy, Saline Upland, Saline Lowland and Sands seed mixtures would be selected from 

the grasses, forbs, and shrubs used for revegetation. Examples of species that would be used for 

revegetation are as follows:
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Grasses

Thickspike wheatgrass (Elymus lanceolatus spp. lanceolatus)

Stream bank wheat grass (Elymus lanceolatus spp. psammophilus) 

Western wheatgrass (Pascopyrum smithii) 

Bluebunch wheatgrass (Pseudoroegneria spicata spp. spicata) 

Beardless wheatgrass (Agropyron inerme) 

Slender wheatgrass (Elymus trachycaulus spp. trachycaulus) 

Basin wildrye (Elymus cinereus) 

Sheep fescue (Festuca ovina) 

Indian ricegrass (Achnatherum hymenoides) 

Canada bluegrass (Poa compressa) 

Canby bluegrass (Poa canbyi) 

Sandberg bluegrass (Poa sandbergii) 

Bottlebrush squirreltail (Elymus elymoides) 

Needle-and-thread grass (Stipa comata) 

Green needlegrass (Stipa viridula) 

Shrubs

Silver sage (Artemisia cana) 

Fringed sagebrush (Artemisia frigida) 

Wyoming big sagebrush (Artemisia tridentata) 

Fourwing saltbush (Atriplex canescens) 

Gardner’s saltbush (Atriplex gardneri) 

Winterfat (Ceratoides lanata) 

Rubber rabbitbrush (Chrysothamnus nauseosus) 

Low rabbitbrush (Chrysothamnus viscidiflorus) 

Spiny hopsage (Grayia spinosa) 

Greasewood (Sarcobatus vermiculatus) 

Gray horsebush (Tetradymia canescens)

Spiny horsebush (Tetradymia spinosa) 

Forbs 

Buckwheat (Eriogonum) 

Penstemon (Penstemon) 

Lupine (Lupinus) 

Paintbrush (Castilleja) 

Globemallow (Sphaeralcea) 

Flax (Linum) 
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2.1.1.14. LIFE OF OPERATION

Under the current mining plan, the Bridger Mine Complex is expected to operate until 2037, but with 

reduced annual coal production. The pit that would advance into Section 24 can only be mined until 2025 

without the proposed mining plan operation. 

2.1.1.15. PROJECT DESIGN FEATURES

The following design elements are discussed in BCC’s existing mine permit and in the 2010 Bridger 

Lease Modification EA (BLM 2010), are currently in effect at the mine, and would also apply to the 

proposed mining plan modification: 

• A water truck is operated, as needed, to control fugitive dust within BCC’s control.

• Identified paleontological, archaeological, and cultural resources are preserved or mitigated in 

conformance with BCC’s existing memorandum of agreement that is part of the existing mining 

operations. 

• Class 3 Cultural Inventory has been completed and cultural clearance has been obtained. Any 

previously undiscovered cultural resources would be investigated if discovered upon entering the 

project area in the modified lease.

• Appropriate fencing is placed around the lease area to ensure livestock are not affected by the 

surface mining activities.

• Application of the Raptor Mitigation Plan, with nesting survey information submitted yearly to 

WDEQ-LQD, WGFD, and U.S. Fish and Wildlife Service (USFWS). 

• Requirement to conduct a breeding bird survey twice each spring to record migratory birds of 

high federal interest, as well as conduct annual nest surveys in areas of raptor concentration near 

the permit area. Information gathered during raptor surveys is submitted yearly to WDEQ-LQD, 

WGFD, and USFWS. Information gathered during surveys and wildlife monitoring is presented 

in BCC’s WDEQ-LQD annual reports.

• Application of wildlife monitoring and protection program that was designed to allow assessment 

of the wildlife response to development of mining activities and reclamation efforts. Through the 

wildlife monitoring program, BCC identifies any substantial wildlife/mining conflicts and 

potential conflicts within its permit boundary. Information gathered during surveys and wildlife 

monitoring is presented in BCC’s WDEQ-LQD annual reports. 

• Application of soil monitoring program, which tests soil prior to application, to identify physical 

and chemical soil characteristics that are inhibitory to plant development. This program helps to

ensure revegetation success.

• Application of vegetation monitoring program to aid in determining when the post-mining land 

use of undeveloped rangeland is met. 

• Application of alternate sediment control system, which implements erosion control measures 

including: 

o hay or straw mulch to stabilize soils (and add a source of organic material), with 

alternative options of cover crops or soil pitting 

o proper slope design (the shaping of reclaimed slopes to slopes with upper convexities, 

middle straight reaches, and lower concave reaches wherever possible) 

o interceptor ditches to slow runoff, reduce erosion, and enhance sediment deposition

o temporary sediment traps when runoff flow cannot be controlled adequately with a check 

dam 
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o containment berms to direct flow into structures such as check dams or temporary 

sediment traps

o revegetation of all reclaimed areas

o vegetative buffer strips to prevent erosion in critical areas

o drainage of disturbed areas into the pit where the water evaporates or is pumped into 

holding ponds (outside the project area) for treatment prior to discharge

o design techniques using computer modeling to evaluate disturbed area runoff prior to 

disturbance and simulation of the various sediment control measures 

o an alternative sediment control monitoring network (SEDCO) to monitor the 

effectiveness of sediment control

o check dams, water bars, and hay or straw bales when the SEDCO monitoring indicates a 

need to stabilize the effects of rills and gullies in reclaimed areas or in other erosionprone areas such as disturbed areas

2.2. Description of Alternatives 

2.2.1. Proposed Action

Under the Proposed Action, the ASLM would approve the application for a mining plan modification for 

federal coal lease WYW02727, which would result in adding 560 acres of federal surface (the project 

area), which includes an estimated 4.5 million tons of federal coal, to the approved mining plan. The 

Proposed Action would result in approximately 104 acres of disturbance from surface mining activities 

and would be a continuation of current surface mining. Federal coal lease WYW02727 was originally 

issued to BCC on October 1, 1969, and was readjusted effective October 1, 1999. The project area is 

adjacent to current surface mining operations at the larger Bridger Mine Complex. 

The 560 acres of added federal surface would be a small part of the existing federal (14,279 acres) and 

private acreages (13,674 acres) being mined. The proposed mining plan modification would not change 

the average annual production rate of the surface mining operation (2,241,843 tons) or the maximum 

annual production rate (3,589,160 tons) for the life of the surface mining operation. This mining plan 

modification would allow approximately 700,000 tons of federal coal per year to be mined on average, 

extending the life of the mine by approximately 13 years when combined with future mining on adjacent 

private lands, from 2025 to 2037.

If BCC is successful in obtaining the mining plan modification, they would provide the access, 

equipment, and technology to mine the coal from this lease area. Any federal coal produced by 

anticipated surface mining methods in the proposed modification would replace coal previously produced 

in other portions of the Bridger Mine Complex, with no resulting change in overall annual coal 

production. BCC’s mining schedule would change under the Proposed Action, with mining of the 

estimated 4.5 million tons of economically recoverable coal in the lease modification project area, along 

with future mining on adjacent lands, being projected to add approximately 13 years to the life of the 

mine, with mining concluding in 2037. If the coal lease modification is not approved, this coal would 

likely be bypassed by BCC. 

The proposed mining plan modification would not displace other competitive commercial interests in the 

lands or deposits, and would not include coal deposits that could be developed by a non-BCC potential or 

existing mining operation. The proposed mining plan modification would not exceed the modified 

acreage limitation of 960 acres, as described in Section 432 of the Energy Policy Act of 2005. 
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2.2.1.1. LOCATION AND OVERVIEW 

The Bridger Mine Complex is approximately 31 miles northeast of Rock Springs in Sweetwater County, 

Wyoming. The project area for the Proposed Action encompasses 560 acres bordering the existing surface 

mine on the southeast and comprises federal surface and subsurface estate owned and managed by the 

BLM. The Public Land Survey System description for the project area is as follows: 240 acres are in the 

SW 1⁄4, S 1⁄2, NW 1⁄4 of Section 12, Township 20 North, Range 100 West Sixth Principal Meridian, and 

320 acres are in the W 1⁄2 of Section 24, Township 20 North, Range 100 West Sixth Principal Meridian, as 

shown on the Black Rock South (1986), Wyoming, U.S. Geological Survey (USGS) 7.5-minute 

quadrangle (see Figure 1-1). 

The Bridger Mine Complex is divided into four distinct areas by drainages that cross the permit area; 

these areas cover both the surface and underground portions of the complex and include the following, 

from north to south: 

Deadman North Area: The area of the mine north of Deadman Wash

Central Mine Area: The area from Deadman Wash to Nine and One-Half Mile Draw

Nine and One-Half Mile South Area: The area south of Nine and One-Half Mile Draw

Tenmile South Area: The area south of Tenmile Draw to the southernmost permit boundary 

The coalfield is located on the northeastern flank of the Rock Springs uplift, a 34-mile-wide by 60-milelong anticlinal structure that generally separates the Green River Basin on the west and the Great Divide

and Washakie Basins on the east. The surface remaining mineable coal reserve is about 9 miles long and 

1 mile wide. The underground mine encompasses an additional mineable coal reserve area of 

approximately 4,500 acres. 

2.2.1.2. PROPOSED MINING METHODS IN MINING PLAN 

MODIFICATION AREA

There are four seams of coal in Sections 12 and 24, designated D5, D4, D3, and D2 from top to bottom. 

The seams generally dip 2 to 5 degrees to the northeast. Coal seam thickness and quality vary in Sections 

12 and 24, ranging from 2 to 15 feet thick (BCC 2009). The information about existing mining operations 

provided in this section comes from the 2010 Bridger Lease Modification EA, which is incorporated by 

reference (BLM 2010).

Mining in Section 12 is projected to be a combination of dragline excavation of the overburden with 

scraper and front-end loader excavation of the interburden material between the coal seams. Figure 2-1 

depicts the area of Section 12 that would be mined. The individual coal seams would be removed by a 

front-end loader as they are uncovered and readied for delivery to the power plant. In this sequence, 

topsoil would first be removed and stockpiled for reclamation using scrapers. The overburden would then 

be drilled for pre-splitting, and then blasted to loosen the material for removal. A combination of dozers 

and draglines would remove the remaining overburden down to the top of the D5 seam. After the D5 

seam has been uncovered, it would be drilled and blasted for removal by the front-end loader and haulage 

to the power plant. Once the D5 seam has been recovered, the scrapers and the front-end loader would 

remove the interburden material over the D4 seam so the coal can be subsequently removed and hauled to 

the power plant. Surface mining in Section 12 is projected to recover only the D5 and D4 seams due to 

the increased depths and the high stripping ratios involved. After the economically recoverable surfacemined portions of the D5 and D4 seams have been removed, BCC proposes to recover additional coal 

reserves from the D5 seam using highwall mining techniques (BCC 2009). The duration of mining in 

Section 12 is expected to be from 2025 through 2035. 
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Mining in Section 24 is projected to be a combination of truck-shovel pre-stripping and dragline 

excavation of the overburden. Figure 2-1 depicts the area of Section 24 that would be mined. A front-end 

loader would remove each coal seam as it is uncovered and readied for delivery to the power plant. In the 

same manner as described above, topsoil would be removed and stockpiled for reclamation using 

scrapers. The overburden would then be drilled for pre-splitting, and then blasted to loosen the material 

for removal. The truck-shovel operation would remove a portion of the overburden material down to a 

level where a combination of dozers and draglines can remove the remaining overburden to uncover the 

D5 seam. After the D5 seam has been uncovered, it would be drilled and blasted for removal by the frontend loader and haulage to the power plant. Once the D5 seam has been recovered, the dragline would 

remove the interburden material over the D4 seam so that this coal can be recovered as previously 

described. After the D4 seam has been uncovered and removed, the dragline would again return to take 

out the interburden and uncover the underlying D3 seam. Core drilling has indicated that the quality of the 

D3 seam is of a lower BTU and of higher sulfur content than can be used at the power plant. In areas 

where this seam is of exceedingly poor quality, it may be bypassed and the coal would be spoiled along 

with the overlying D3 interburden and the underlying D1 interburden material. Whether the D3 seam is 

recovered or not, the dragline would continue the excavation of the interburden material until the D1 

seam is uncovered. The D1 seam would subsequently be removed and hauled to the power plant as 

previously described. The D1 seam is the deepest coal in the sequence and would continue to be mined 

until the economic stripping limit is reached. There are currently no plans to recover additional coal 

reserves in this section using highwall mining techniques (BCC 2009). The duration of mining in Section 

24 is expected to be from 2028 through 2037.

The following sections provide more detail regarding the mining methods and facilities. The methods

would generally be the same as those that occur at the current surface-mining operation under the 

existing permit. A diagram of the general flow of coal during the proposed mining activities is depicted 

in Figure 2-2.
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Figure 2-2. Coal flow diagram. 
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2.2.1.2.1. Topsoil

Soil removal and storage would be carried out as described in Section 2.1.1.2. 

2.2.1.2.2. Temporary Overburden Stockpile

Temporary overburden stockpiles would occur as described in Section 2.1.1.3.

2.2.1.2.3. Access and Haul Roads

No new primary roads would be constructed into the mining plan modification areas. Existing haul roads 

and ramps into the existing pit would be used for access. Existing ramps into the pit would be extended as 

the pit progresses cut by cut into the modification areas. Highwall access for drill benches would be on a 

dragline deadhead road on the area where topsoil has been removed on the highwall in an area classified 

as an active mining and pit area.

2.2.1.2.4. Power Lines

No new power lines are anticipated for the mining plan modification areas. The power line loop that 

would serve the modification areas has already been constructed on permitted rights-of-way around the 

perimeter of the modification areas. This power line loop already serves the existing mine operation. 

Design of all proposed electrical distribution lines conforms to the Suggested Practices for Raptor 

Protection on Power Lines: The State of the Art in 1996 (APLIC et al. 1996). If new information on 

BACT for improved electrocution protection becomes available, it would be used to update power line

designs as necessary to prevent raptor electrocution. Minor modifications to power lines may be required 

during the life of the surface mine.

2.2.1.2.5. Mine Facilities

The proposed mine permit expansion area would use the same mine facilities that are described in Section 

2.1.1.6.

2.2.1.2.6. Ponds, Impoundments, Diversions

Ponds, impoundments, and diversions would be used in the same manner as described in Section 2.1.1.7.

No new ponds would be needed under the Proposed Action.

2.2.1.2.7. Water Source

The water sources used for mining operations in Sections 12 and 24 would be the same as those described 

in Section 2.1.1.8. The mining operations in Sections 12 and 24 would not affect the existing annual water 

usage at the Bridger Mine Complex. Water usage would consist of pumping water out of pits into holding 

ponds on an as-needed basis, and pumped from the holding ponds into water trucks to be used for dust 

suppression on haul roads and work areas. Water would also be pumped from overburden dewatering 

wells on the existing permit area. This water would also be pumped to holding ponds and used for dust 

suppression. Annual water usage for dust suppression at the Bridger Mine Complex ranges between 70 

million and 170 million gallons. 

2.2.1.2.8. Open Pits

Development of the pits would occur the same way as described in Section 2.1.1.9.
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2.2.1.2.9. Hazardous Materials

Use of hazardous materials during the mining operations in Sections 12 and 24 would be the same as 

currently exists in the adjacent operating pit areas (see Section 2.1.1.10). No hazardous materials would 

be produced by the proposed mining activities, and no hazardous materials would be stored in the mining 

plan modification areas.

2.2.1.2.10. Mine Personnel

The mining operations in Sections 12 and 24 would not affect existing hours of operation or number of 

mine personnel for the Bridger Mine Complex (see Section 2.1.1.11), because existing employees would 

conduct mining in Sections 12 and 24 as mining is completed in other areas of the Bridger Mine 

Complex.

2.2.1.2.11. Transportation

No rail transport would be needed for the proposed mining plan modification area. As described in 

Section 2.1.1.12, all coal transport would be accomplished using haul trucks and an overland conveyor. 

The overland conveyor would be used in the same way for the mining plan modification areas as it is for 

the existing permit area. There is a truck dump station at the southernmost point on the overland 

conveyor, which is northwest of the mining plan modification area. Coal would be transported from the 

pits in the modification areas to this truck dump station by an existing fleet of haul trucks. No public 

roads would be used in the transportation of coal from the Bridger Mine Complex to the Jim Bridger 

Power Plant.

2.2.1.2.12. Reclamation

The reclamation measures described in Section 2.1.1.13 would be applied to the mining operations in 

Sections 12 and 24.

2.2.1.2.13. Life of Operation

The proposed mining plan modification area is expected to extend the life of the mine by 13 years, from 

2025 to 2037, with final reclamation following through 2046.

2.2.2. No Action Alternative

The No Action Alternative would reject the application for a mining plan modification for federal coal 

lease WYW02727, which would result in an estimated 4.5 million tons of federal coal not being mined at 

this time. Under the No Action Alternative, the 560 acres of federal surface would not be added to the 

approved mining plan, and the estimated 4.5 million tons of federal coal within this acreage would not be 

mined at this time. BCC would continue to mine coal within the existing permit boundary of the Bridger 

Mine Complex.

Under this alternative, BLM would continue to manage the federal surface lands in the project area for 

multiple use, including livestock and wild horse grazing, recreation, and oil and gas exploration and 

development.
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2.2.3. Alternatives Considered but Eliminated from Detailed 

Analysis 

This section discusses alternatives that were considered but eliminated from detailed analysis. Reasons 

that an alternative might not be considered in detail, in accordance with the CEQ’s NEPA implementing 

regulations (40 CFR 1502.14), are as follows: 

The alternative is ineffective (does not respond to the purpose and need). 

The alternative is technically or economically infeasible, considering whether implementation of 

the alternative is likely given past and current practice and technology). 

The alternative is inconsistent with the basic policy objectives for the management of the area 

(e.g., it is not in conformance with land use plans). 

The alternative is remote or speculative. 

The alternative is substantially similar in design to an alternative that is analyzed. 

The alternative is substantially similar in impacts to an alternative that is analyzed. 

No other alternatives were identified that meet the purpose and need for this action. No unresolved 

conflicts concerning alternative uses of available resources were identified. There is no logical 

competitive interest based on the use of the lands or mining of the deposits because 

BCC is the lessee of record, holding the private, state, and federal leases adjacent to the proposed 

lease modification;

the lease modification would allow a continuum of an existing mining block and could not be 

economically developed on a stand-alone basis;

there is no other nearby operation that could economically mine the proposed lease modification; 

and 

the only logical access is from the Bridger Mine Complex. 

During the public scoping period, five alternatives were suggested for detailed analysis. These 

alternatives are described below, along with rationales for why they were dismissed from detailed 

analysis.

2.2.3.1. ALTERNATIVE MINING LEVELS 

This alternative would limit the amount of coal tonnage and/or acreage to be mined to lower levels than 

are proposed under the Proposed Action. This alternative was aimed at limiting the direct and indirect 

impacts of mining, hauling, and coal combustion. This alternative was not considered in detail because it 

would not meet the purpose and need (see Section 1.3) and would be inconsistent with the MLA 

requirement to maximize recovery by achieving maximum economic recovery of this energy resource (43 

CFR 3480.0-5 (21)). OSMRE’s purpose and need is to evaluate BCC’s proposed mining plan 

modification submitted in accordance with the federal coal lease granted to BCC.

2.2.3.2. LOW OR NO POLLUTANT EMITTING EQUIPMENT

This alternative would require the use of equipment that produces less or no emissions, such as natural 

gas-powered vehicles and machinery or electric machinery powered by solar panels or other renewable 

energy sources. The Bridger Mine Complex surface mine uses Marion model 8200 walking draglines as 

the primary earthmoving equipment. Draglines are powered by electricity. Most mobile equipment is 

diesel powered. All diesel-powered equipment meets U.S. Environmental Protection Agency (EPA) 
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emissions standards. New purchases of diesel-powered mobile equipment would include Tier 4 engines.

The Bridger Mine Complex is a relatively small contributor of the emissions related to engine combustion 

(primarily carbon dioxide [CO2] and oxides of nitrogen [NOX]) in the region. The cost to make the switch 

to equipment powered by a different fuel (such as natural gas– or solar-powered equipment) for 104 acres 

of federal coal would be cost prohibitive for the minimal benefit to the regional air quality. In addition, 

the use of natural gas–powered engines in mining equipment is relatively new and some types of 

equipment would not be available for replacement with natural gas–powered engines. The use of solar 

power to run large equipment has not been tested and is not considered technologically feasible at this 

time. Similarly, retrofitting existing equipment with additional emissions control devices would be 

expensive with limited effect on regional air emissions. OSMRE has not brought forward this alternative 

for full analysis because requiring natural gas– and solar-powered engine technology and retrofitting 

existing equipment is not economically or technically feasible for all equipment at the Bridger Mine 

Complex; and would likely have substantially similar effects as the Proposed Action.

2.2.3.3. AIR QUALITY MITIGATION

This alternative would apply air quality mitigation measures to the proposed mining activities. The 

mitigation measures under this alternative would include such measures as stronger emissions limits for 

power plants fueled by the mine, efforts to eliminate nitrogen dioxide (NO2)1 emissions during blasting 

operations, and compensatory reductions in emissions for emissions that would result from the proposed 

mining activities. This alternative was eliminated from detailed analysis because OSMRE does not have 

the regulatory authority to require electricity-generating plants to reduce emissions because the emissions 

are regulated by the States or Counties where the plants are located. Any mitigation measure proposed by 

OSMRE imposing more stringent emission limits at generating stations and upon oil and gas operators is 

beyond OSMRE’s authority and its implementation would be highly remote and speculative.

Furthermore, the Bridger Mine Complex must comply with the requirements of the Clean Air Act and 

obtain approval of an air quality permit from the WDEQ Air Quality Division. The air permit would 

incorporate measures that address the issues this alternative seeks to address. OSMRE can consider 

potential mitigation measures to limit emissions from the proposed mining activities, such as dust from 

coal and overburden stockpiles or emissions from mine equipment. Prior to issuance of Bridger Mine 

Complex’s 2010 air quality permit (Air Quality Permit MD-9156), NO2 emissions, including NO2 

emissions from blasting, were analyzed. No limitations to NO2 were added to the air permit based on the 

results of the analysis.

2.2.3.4. LIMIT OR REDUCE GREENHOUSE GAS EMISSIONS

This alternative would limit or reduce greenhouse gas (GHG) emissions associated with the proposed 

mining activities by requiring BCC to secure an increase in the efficiency of the power plants it fuels to 

reduce the total CO2 rate, requiring the use of low-carbon fuels for the operation of heavy machinery, 

and/or requiring BCC to use renewable energy to power the Bridger Mine Complex. This alternative was 

eliminated from detailed analysis because OSMRE does not have the regulatory authority to require 

electricity-generating plants to reduce emissions because the emissions are regulated by the States or 

Counties where the plants are located. Any mitigation measure proposed by OSMRE imposing more 

stringent emission limits at generating stations and upon oil and gas operators is beyond OSMRE’s 

authority and its implementation would be highly remote and speculative. Furthermore, the Bridger Mine 

Complex must comply with the requirements of the Clean Air Act and obtain approval of an air quality 

permit from the WDEQ Air Quality Division. The air permit would incorporate measures that address the 

issues this alternative seeks to address.

 1 The EPA uses NO2 as the indicator for the larger group of nitrogen oxides (oxides of nitrogen) or NOx. However, emissions are 

usually reported as NOx.
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2.2.3.5. REQUIRED OFF-SITE MITIGATION OR COMPENSATION 

FOR IMPACTS

This is not a reasonable alternative to the mining plan being considered. The effects of coal combustion 

are analyzed in the Proposed Action 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 analysis 

concluded impacts to air resources under the Proposed Action would be minor and there would not be 

significant impacts to air resources under the Proposed Action and no mitigation was recommended. Any 

mitigation measure proposed by OSMRE imposing more stringent emission limits on non-coal operators 

is beyond OSMRE’s authority and its implementation would be highly remote and speculative. The 

Proposed Action has the potential to emit CO2 at levels identified in Section 4.2.1. CO2 emissions from 

the Proposed Action would be well below the EPA’s Final Mandatory Reporting of Greenhouse Gases 

Rule threshold of 25,000 metric tons per year of carbon dioxide equivalent (CO2e) (40 CFR Part 98). 

Because no significant impacts are predicted from CO2 emissions attributed to the Proposed Action, an 

alternative that requires compensatory mitigation is eliminated from detailed analysis.

3. AFFECTED ENVIRONMENT

3.1. Introduction

This chapter describes the existing environment of the area that would be affected by the Proposed Action 

or No Action Alternative. The affected environment was considered and analyzed by an interdisciplinary 

team, as documented in Table 3-1. The table indicates which resources are either not present in the project 

area or would not be affected to a degree that requires detailed analysis. Guidance at 40 CFR 1500.1(b) 

states that NEPA documents “must concentrate on the issues that are truly significant to the action in 

question.” The elimination of non-relevant resources is consistent with the guidance in 40 CFR 1500.4, 

especially using the scoping process to identify significant environmental issues, deemphasize 

insignificant issues, and emphasize areas that are useful to decision-makers and the public. Resources or 

issues that could be affected by the Proposed Action or the No Action Alternative are analyzed in the 

remainder of this chapter.

Table 3-1. Resources Analyzed in Detail and Resources Eliminated from Detailed Analysis

Resource Rationale for Analysis or Elimination from Analysis

Air quality and GHG emissions See discussion in Affected Environment and Environmental Consequences 

sections.

Alluvial valley floors Dismissed from analysis. No alluvial valley floors are present in the project 

area. The subirrigated alluvial deposits are limited in area, have poor soil and 

water quality, and are of no value for agricultural development beyond grazing 

(BCC 2016).

Cultural resources and Native American religious 

concerns

See discussion in Affected Environment and Environmental Consequences 

sections.

Environmental justice The closest town to the project area is Superior, Wyoming, approximately 17 

miles to the northwest. The Proposed Action would have no impacts to 

environmental justice populations because no such populations are located 

near the Bridger Mine Complex.

Farmlands (prime or unique) Dismissed from analysis. No prime or unique farmland is present in or near the 

project area.
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Resource Rationale for Analysis or Elimination from Analysis

Fish and wildlife See discussion in Affected Environment and Environmental Consequences

sections.

Floodplains Dismissed from analysis. There are no floodplains in the project area. 

Geology and minerals See discussion in Affected Environment and Environmental Consequences 

sections.

Hazardous or solid waste Dismissed from analysis. The Proposed Action is a continuation of mining 

within the existing mine permit boundary and would not change the mine’s 

current hazardous or solid waste practices. 

Livestock grazing Dismissed from analysis. The Proposed Action is a continuation of mining 

within the existing mine permit boundary and livestock grazing is excluded 

from the boundary by fencing.

Noise Dismissed from analysis. The Proposed Action is a continuation of mining 

within the existing mine permit boundary and would follow the current blasting 

plan that is already in place. 

Ownership and land use Dismissed from analysis. The Proposed Action is a continuation of mining 

within the existing mine permit boundary and would not change current 

ownership or land use.

Paleontology Dismissed from analysis. No significant paleontological finds have been made 

in the course of 42 years of both surface and underground mining at the 

Bridger Mine Complex. BCC’s lease modification (WYW02727) requires that if 

paleontological resources, either large and conspicuous, and/or of significant 

scientific value are discovered during mining operations, the find will be 

reported to the Authorized Officer immediately and mining operations will be 

suspended within 250 feet of said find.

Recreation Dismissed from analysis. The Proposed Action is a continuation of mining 

within the existing mine permit boundary (where no recreation currently 

occurs).

Socioeconomics See discussion in Affected Environment and Environmental Consequences 

sections.

Soils See discussion in Affected Environment and Environmental Consequences 

sections.

Threatened, endangered, candidate, and specialstatus animal speciesDismissed from analysis. Site-specific data from BCC’s existing mine permit 

indicate no potential for any threatened, endangered, candidate, or specialstatus animal species to occur within the analysis area for the proposed 

project due to the lack of suitable habitat.

Threatened, endangered, candidate, and specialstatus plant speciesDismissed from analysis. Site-specific data from BCC’s existing mine permit 

indicate no potential for any threatened, endangered, candidate, or specialstatus plant species to occur in the project area.

Topography and physiography See discussion in Affected Environment and Environmental Consequences 

sections.

Transportation and access Dismissed from analysis. The Proposed Action is a continuation of mining 

within the existing mine permit boundary.

Vegetation (including invasive species and 

noxious weeds)

See discussion in Affected Environment and Environmental Consequences 

sections.

Visual resources Dismissed from analysis. The Proposed Action is a continuation of mining 

within the existing mine permit boundary.

Water resources and water quality (groundwater, 

surface water, and hydrologic conditions)

See discussion in Affected Environment and Environmental Consequences 

sections.

Wetlands and riparian zones See discussion in Affected Environment and Environmental Consequences 

sections.
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For each element or resource brought forward for analysis in this EA, an analysis area is identified in 

which to examine potential project-related impacts. The analysis area is defined as the outer boundary of 

an area that encompasses potential direct and indirect impacts that may affect the resource. Issues 

identified during interdisciplinary team analysis of the area and public scoping have guided the 

development of the affected environment and environmental consequences sections. 

3.2. General Setting

The project area is 560 acres in size and is located approximately 31 miles northeast of Rock Springs, 

Wyoming. The general topography of this portion of Wyoming consists of numerous bluffs and peaks 

rising from an area-wide base elevation of 6,000 feet above mean sea level (BCC 2016). The project area 

is situated on the southwest side of the Continental Divide, with elevations ranging from 6,700 to 6,900 

feet.

3.3. Air Quality and Climate Change

The analysis area for impacts to air quality is Sweetwater County, Wyoming. This area was chosen 

because it is a typical spatial boundary used to determine compliance with the National Ambient Air 

Quality Standards (NAAQS) established in the Clean Air Act. A county is often selected to be the 

geographic area evaluated or designated as meeting or not meeting NAAQS. In addition, Sweetwater 

County includes the area analyzed as part of Bridger Mine Complex’s 2009 air quality permit 

modification application. The analysis area is approximately 6,672,640 acres (Gardner 2016).

The analysis area for impacts to climate change is the Great Plains region (comprising the states of 

Montana, Wyoming, North Dakota, South Dakota, Nebraska, Kansas, Oklahoma, and Texas), as defined 

in Climate Change Impacts in the United States: The Third National Climate Assessment (Assessment), a 

comprehensive report on climate change and its impacts in the United States (Shafer et al. 2014). This 

area includes Sweetwater County and was chosen because climate change and global warming are 

regional and global phenomena.

3.3.1. Local Climate and Meteorology

The climate of the area is characteristic of the Northern Great Plains Continental Steppe. Winters are 

typically very cold, summers are warm, and precipitation is light. There is considerable variation in 

annual and seasonal temperature and precipitation (BCC 2016). Summer is usually influenced by Pacific 

Maritime air masses (dried by the Cascade and Rocky Mountain ranges). Winter is dominated by highpressure, cold Canadian-Arctic air masses that move southward along the eastern front of the Rocky 

Mountains. Most precipitation occurs during the spring and early summer.

Meteorological data from the Bridger Mine Complex indicate that wind speed from January to December 

2015 averaged 4.5 meters per second. The predominant wind direction was from the west-southwest 

sector, accounting for 18.4% of the possible winds (Figure 3-1). Total precipitation during this period was 

6.33 inches, and the average temperature was 44.2 degrees Fahrenheit (IML Air Science 2015).
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Figure 3-1. Bridger Mine Complex wind rose (January–December 2015). Source: IML Air Science (2015).

3.3.2. Air Quality

3.3.2.1. REGULATORY COMPLIANCE

3.3.2.1.1. NAAQS and WAAQS

The EPA established NAAQS to limit the amount of air pollutants considered harmful to public health and 

the environment. Primary and secondary standards have been set for six criteria pollutants: carbon 

monoxide (CO), lead, nitrogen dioxide (NO2), (also known as nitrogen oxides, oxides of nitrogen, or NOx), 

ozone (O3), sulfur dioxide (SO2), and particulate matter (PM). Ground-level ozone is not directly emitted 

into the air but is created by chemical reactions between NOx and volatile organic compounds (VOCs) in 

the presence of sunlight. The primary standards provide public health protection and include protection for 

sensitive populations such as children and the elderly. Secondary standards provide public welfare 

protection, which includes protection against decreased visibility and damage to animals, crops, vegetation, 

and buildings (EPA 2016a). Areas that do not comply with NAAQS requirements for criteria pollutants are 

considered nonattainment areas. A particular geographic region may be designated an attainment area for 

some pollutants and a nonattainment area for others. A portion of Sweetwater County (the Upper Green 
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River Basin area) is currently a nonattainment area for O3 (8-hour) (EPA 2016b). The Bridger Mine 

Complex is not in the Upper Green River Basin and is in an area currently considered in attainment with 

NAAQS (WDEQ-AQD 2012). As a result, the General Conformity Rule does not apply to the Proposed 

Action (the General Conformity Rule ensures that actions taken by federal agencies in nonattainment and 

maintenance areas are consistent with a State’s plans to meet NAAQS [CAA Section 176(c)]).

The WDEQ Air Quality Division (WDEQ-AQD) has also established its own ambient air quality 

standards—the Wyoming Ambient Air Quality Standards (WAAQS). The NAAQS and WAAQS are 

summarized in Table 3-2. 

Table 3-2. NAAQS and WAAQS

Pollutant Primary/ 

Secondary Form Averaging Time NAAQS WAAQS

CO Primary Not to be exceeded more than 

once per year

8 hours 9 ppm 9 ppm

1 hour 35 ppm 35 ppm

Lead Primary and 

secondary

Not to be exceeded Rolling 3-month 

average

0.15 μg/m3 0.15 μg/m3

NO2 Primary 98th percentile of 1-hour daily 

maximum concentrations, 

averaged over 3 years

1 hour 100 ppb 100 ppb

Primary and 

secondary

Annual mean 1 year 53 ppb 53 ppb

Ozone Primary and 

secondary

Annual fourth-highest daily 

maximum 8-hour concentration, 

averaged over 3 years

8 hours 0.070 ppm 75 ppb

Particulate 

Matter

PM2.5 Primary Annual mean, averaged over 3 

years

1 year 12 μg/m3 12 μg/m3

Secondary Annual mean, averaged over 3 

years

1 year 15 μg/m3 15 μg/m3

Primary and 

secondary

98th percentile, averaged over 

3 years

24 hours 35 μg/m3 35 μg/m3

PM10 Primary and 

secondary

Not to be exceeded more than 

once per year on average over 

3 years

24 hours 150 μg/m3 150 μg/m3

N/A Annual mean, averaged over 3 

years

24 hours N/A 50 μg/m3

SO2 Primary 99th percentile of 1-hour daily 

maximum concentrations, 

averaged over 3 years

1 hour 75 ppb 75 ppb

Secondary Not to be exceeded more than 

once per year

3 hours 0.5 ppm 0.5 ppm

Source: EPA (2016a); WDEQ (2015)

Note: N/A = not applicable; ppb = parts per billion; ppm = parts per million; PM2.5 = PM less than 2.5 micrometers in diameter; PM10 = PM between

2.5 and 10 micrometers in diameter; μg/m3 = micrograms per cubic meter

3.3.2.1.2. Ambient Air Quality in the Analysis Area

Compliance with NAAQS is demonstrated by monitoring for ground-level atmospheric air pollutant 

concentrations. WDEQ-AQD operates and maintains a network of air quality monitoring stations across 

the state to collect ambient air quality data and to evaluate compliance with the NAAQS. Particular 

stations monitor for certain pollutants; not all stations monitor all pollutants. Table 3-3 summarizes 

ambient air quality recorded at air quality monitors in Sweetwater County (outside the Upper Green River 

Basin) from 2013 to 2015. CO was not monitored in Sweetwater County and most of Wyoming during 

this time because past monitoring indicated that CO levels were relatively low and that the benefit of 

monitoring was not justified for a long-term period (WDEQ-AQD 2016a). All data shown in Table 3-3 
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are in compliance with NAAQS and WAAQS, indicating that the air quality in the analysis area is 

meeting federal and state standards. The EPA has identified High Priority Violations of the CAA at the 

Jim Bridger Power Plant. High Priority Violations are violations of regulations authorized by the CAA 

that warrant additional scrutiny to ensure that state, local, territorial, and tribal agencies respond to such 

violations in an appropriate manner and, if needed, have access to federal assistance. However, the 

analysis of impacts to air resources assumes that the Jim Bridger Power Plant would comply with its air 

quality permit requirements and the CAA.

Table 3-3. Ambient Air Quality Data in the Analysis Area from 2013 through 2015

Criteria Pollutant 

and Averaging Time 

(Form)

Primary 

NAAQS 

Monitoring Station Data 

Hiawatha Station

(43 miles southeast 

of Rock Springs)

Moxa Arch Station

(25 miles northwest of 

Green River)

Rock Springs

(in Rock Springs)

Wamsutter

(2 miles west of 

Wamsutter)

NOx

1 hour

(annual 98% of daily 

maximum 1-hour 

average)

100 ppb – 19 ppb (2013)

18 ppb (2014)

22 ppb (2015)

– 38 ppb (2013)

32 ppb (2014)

35 ppb (2015)

1 year (annual 

arithmetic mean)

53 ppb – 2 ppb (2013)

2 ppb (2014)

2 ppb (2015)

– 4 ppb (2013)

3 ppb (2014)

3 ppb (2015)

Ozone

8 hours

(4th highest 8-hour 

average)

0.070 ppm 0.064 ppm (2013)

0.062 ppm (2014)

0.062 ppm (2015)

0.067 ppm (2013)

0.063 ppm (2014)

0.071 ppm (2015)*

– 0.064 ppm (2013)

0.060 ppm (2014)

0.060 ppm (2015)

Particulate Matter

PM2.5 1 year

(annual 

arithmetic 

mean)

12 μg/m3 – – 5.1 μg/m3 (2013)

4.5 μg/m3 (2014)

4.8 μg/m3 (2015)

–

24 hours 

(98% 24-hour 

average)

35 μg/m3 – – 12 μg/m3 (2013)

10 μg/m3 (2014)

19 μg/m3 (2015)

–

PM10 24 hours 

(highest 24-

hour average)

150 μg/m3 – 79 μg/m3 (2013) 

67 μg/m3 (2014)

52 μg/m3 (2015)

43 μg/m3 (2013)

39 μg/m3 (2014)

54 μg/m3 (2015)

193 μg/m3 (2013)† 

41 μg/m3 (2014)

47 μg/m3 (2015)

SO2

1 hour (annual 99% 

1-hour average)

75 ppb – 20 ppb (2013)

16 ppb (2014)

18 ppb (2015)

– –

Source: WDEQ-AQD (2016a).

Note: ppb = parts per billion; ppm = parts per million; PM2.5 = PM less than 2.5 micrometers in diameter; PM10 = PM between 2.5 and 10 micrometers in 

diameter; μg/m3 = micrograms per cubic meter

* To comply with the 8-hour ozone NAAQS, the daily maximum 8-hour ozone averages are ranked over a year. The 3-year average of the fourthhighest annual value must not exceed 0.070 ppm. At the Moxa Arch station, the 3-year average of the fourth-highest annual value is 0.067 ppm, which 

indicates compliance with the NAAQS. † To comply with the 24-hour PM10 NAAQS, a monitor may only have one exceedance (a 24-hour average concentration greater than 150 μg/m3) per 

year over a 3-year period. The design value is the average number of exceedances per year from 2013–2015. At the Wamsutter station, the design 

value for 24-hour PM10 from 2013–2015 is 0.3, which indicates compliance with the NAAQS.

3.3.2.1.3. Prevention of Significant Deterioration

The Prevention of Significant Deterioration (PSD) is a CAA New Source Review permitting program for 

new and modified major sources of air pollution that are located in attainment areas. It is designed to 

prevent NAAQS violations, to preserve and protect air quality in sensitive areas, and to protect public 
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health and welfare (EPA 2016c). Under PSD regulations, the EPA classifies airsheds as Class I, Class II, 

or Class III. Congress designated certain existing areas as mandatory Class I areas, which preclude 

redesignation to a less restrictive class. Class I areas are those areas allowing for very little deterioration 

of air quality. They are areas of special national or regional natural, scenic, recreational, or historic value 

for which PSD regulations provide extra protection. Class II areas allow moderate deterioration and Class 

III areas allow more deterioration, but in all cases, pollutant concentrations cannot violate any of the 

NAAQS (National Park Service 1981).

A PSD increment prevents the air quality in clean areas from deteriorating and is the maximum allowable 

increase in ambient pollutant concentrations. Significant deterioration is said to occur when the amount of 

new pollution would exceed the applicable PSD increment (EPA 2016c). The allowable PSD increments 

of new pollution are very small in Class I areas.

Wyoming has seven Class I areas (national parks and wilderness areas); the closest is the Bridger 

Wilderness, approximately 63 miles north of the project area (EPA 2012). Because of its distance from 

the project area, it would not be affected by the Proposed Action. All portions of Wyoming outside of 

Class I areas are designated as Class II areas. The project area is located in a Class II area.

PSD requirements are applicable to a source if it has the potential to exceed the major source thresholds 

of either 100 or 250 tons per year of a regulated pollutant, depending on the type of pollutant. For 

stationary source categories listed in the regulation, the threshold is 100 tons per year. For unlisted source 

categories, such as surface mining operations, the threshold is 250 tons per year. PSD regulations would 

not apply to the Proposed Action because it does not have the potential to emit 250 tons per year of any 

air pollutant (it is not a major source) and because there would be no change to current annual emissions 

at the Bridger Mine Complex (no air permit modification would be required).

Air Quality Related Values

An air quality related value (AQRV) is defined as a resource “for one or more Federal areas that may be 

adversely affected by a change in air quality. The resource may include visibility or a specific scenic, 

cultural, physical, biological, ecological, or recreational resource” identified by a federal land manager for 

a particular area” (National Park Service, U.S. Forest Service, and U.S. Fish and Wildlife Service

2010:4). The requirement to assess impacts to AQRVs is established in the PSD rules. The federal land 

manager for each Class I area has the responsibility to define and protect the AQRVs at such areas, and to 

consider whether new emissions from proposed major facilities (or modifications to major facilities)

would have an adverse impact on those values. Since the Proposed Action does not meet the applicability 

requirements of the PSD rule, no assessment of AQRV impacts is needed.

3.3.2.1.4. Other Air Quality Regulations

Emissions sources generally fall into two broad categories: stationary and mobile. Stationary sources are 

non-moving, fixed sources of air pollution that emit pollutants through process vents/stacks or through 

fugitive releases. Stationary sources are classified as major or minor. A major source emits or has the 

potential to emit a regulated air pollutant in quantities above defined CAA thresholds. Stationary sources 

that are not major are considered minor or area sources. The Bridger Mine Complex is a minor source. 

Section 111 of the CAA requires the EPA to establish federal emission standards for source categories 

which cause or contribute significantly to air pollution (New Source Performance Standards, or NSPS). 

NSPS regulations limit emissions from source categories to minimize the deterioration of air quality. 

Stationary sources are required to meet these limits by installing new equipment or adding pollution 

controls to older equipment. The Bridger Mine Complex operates existing equipment that is subject to 
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NSPS regulations (e.g., passive enclosure control systems, open coal storage piles, and coal truck dumps); 

however, the Proposed Action would not require the purchase or use of new equipment or source 

categories potentially subject to NSPS regulations.

Section 112 of the CAA requires the EPA to promulgate regulations establishing emission standards for 

each category or subcategory of major sources and area sources of hazardous air pollutants (National 

Emissions Standards for Hazardous Air Pollutants, or NESHAPs). Hazardous air pollutants, or HAPs 

(e.g., benzene, perchloroethylene, and mercury) are known or suspected to cause cancer or other serious 

health effects. The EPA regulates 187 HAPs through Maximum Achievable Control Technology (MACT) 

standards, which are individual emission standards developed for a particular stationary source category. 

Each MACT standard applies to major sources in the industrial source category; major sources are those 

that emit more than 10 tons per year of a single HAP or 25 tons per year of any combination of HAPs 

(EPA 2016d). The EPA also regulates HAPs from mobile sources such as highway vehicles and non-road 

equipment; at least six rules or control programs have been promulgated to reduce these emissions. The 

Proposed Action would not increase annual emissions at the Bridger Mine Complex and would not 

require any changes that are subject to NESHAPs.

Section 169A of the CAA established a national visibility goal to prevent future visibility impairment and 

remedy any existing impairment in national parks and wilderness areas (Class I areas). Visibility refers to 

the clarity with which scenic vistas and landscape features are perceived at great distances. Impairment

refers to human-caused air pollution. In 1999, the EPA promulgated the Regional Haze Rule to address 

regional haze, which refers to haze that impairs visibility in all directions over a large area. Haze forms 

when sunlight encounters particle pollution in the air. The Regional Haze Rule calls for state and federal 

agencies to work together to establish goals and emission reduction strategies to improve visibility in 

Class I areas (EPA 2001). States are required to address visibility in their State Implementation Plans. 

Because the Proposed Action would not increase annual emissions at the Bridger Mine Complex nor 

require changes to its air permit, it is not subject to the Regional Haze Rule.

3.3.2.2. BRIDGER MINE COMPLEX EMISSIONS

The project area is part of the larger Bridger Mine Complex. The most recent Bridger Mine Complex 

emissions inventory data are summarized in Table 3-4. An emissions inventory is a summary of 

emissions for a particular source during a given time period. The Bridger Mine Complex emissions data 

include both the underground and surface portions of the mine. Surface mining emissions would be 

difficult to separate from underground mining emissions because of interrelated components such as 

shared equipment and vehicle traffic.

Table 3-4. Bridger Mine Complex 2014 and 2015 Emissions Inventories

Pollutant

Emissions (tons per year)

2014 2015

CO 169.0 327.0

NOx 193.6 245.3

PM10 923.2 888.8

PM2.5 196.0 194.5

Sulfur oxides 19.0 22.0

Note: PM2.5 values are calculated using EPA emission factors. The increase in CO and NOx emissions between 2014 and 2015 is primarily due to an 

increase in blasting. 

Source: BCC (2014a, 2015).
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As evident in Table 3-4, PM is the primary pollutant of concern at the Bridger Mine Complex. The main 

sources of PM consist of the following: 

fugitive emissions from exposed areas and stockpiles

emissions from coal and overburden haulage 

emissions from topsoil stripping, haulage, and placement 

blasting emissions 

emissions from loading and dumping coal and overburden 

emissions from engine tailpipes

NOx emissions at the Bridger Mine Complex come from gases produced from blasting, gases related to 

air heating equipment, and from diesel-powered equipment. CO and SO2 also come from blasting and 

tailpipe emissions. 

Emissions of air pollutants at the Bridger Mine Complex are currently controlled and limited by air 

quality permits issued by WDEQ-AQD (Air Quality Permits MD-9156 and MD-12225). Annual PM 

tonnage limits for three baghouses are established in MD-9156. Neither air permit sets limits for 

emissions of criteria pollutants other than PM, but an annual maximum coal production rate of 9.0 million 

metric tons is established in MD-9156 (surface mining is limited to a maximum coal production of 2.5 

million metric tons per year). Other limits and requirements outlined in the air permits include the 

following: 

Opacity limitations and daily inspections for the three baghouses

Daily inspections of passive enclosure systems for visible emissions 

Opacity limitations, weekly inspections, and control effectiveness demonstrations for truck 

dump control systems

Limitation of multiple coal storage stockpiles to certain sizes and throughputs 

Treatment of sealed coal stockpiles and associated active work areas with a sealant, water, or 

chemical dust suppressants

Treatment of all permanent haul roads with a chemical dust suppressant to control fugitive dust 

emissions (fugitive dust is PM released to the air by wind or similar forces)

Treatment of temporary haul routes with water and/or chemical dust suppressants

Effective stabilization of topsoiled areas (of a certain size) that are not revegetated within 60 

days topsoil laydown completion 

Operation of an ambient particulate monitoring program and meteorological station 

Implementation of contingency action plan for high particulate levels

Implementation of a fugitive coal dust emissions control plan 

As part of the application for Air Quality Permit MD-9156 and under the guidance of WDEQ-AQD, 

modeling of PM10 and NOX emissions from the Bridger Mine Complex was performed using the 

Industrial Source Complex 3 Long-Term model (IML Air Science 2009). Annual average impacts to 

ambient air were modeled using 10,000 sources and receptors. PM10 annual concentrations from all 

modeled emission sources (Bridger Coal, Leucite Hills, and the Black Butte Mine) were determined for 

each receptor location. All PM10 modeled values were below the NAAQS. A NOx significance analysis 

was conducted to determine the extent of significant NOx impact from the Bridger Mine Complex. 
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Significance was defined as impacts greater than or equal to 1 microgram per cubic meter (μg/m3). Model 

receptors from the PM10 analysis were used to model NOx impacts. Results demonstrated that the 1-μg/m3 

isopleths fall well inside the maximum extent of these receptors. Maximum Bridger Mine Complex 

contribution to boundary receptor concentrations for NOx were shown to be 4.0 μg/m3 in 2010 and 4.9 

μg/m3 in 2011 (the years 2010 and 2011 were selected as worst-case scenarios to model) (IML Air 

Science 2009). 

As required in the air permits, the Bridger Mine Complex operates a particulate and meteorological 

monitoring network that includes two PM10 continuous particulate monitors (JB4 and JB5). Recent 

monitoring data from 2013–2015 are summarized in Table 3-5 below.

Table 3-5. Bridger Mine Complex 2013–2015 Particulate Concentration Summaries

PM10 Measurement 

PM10 Concentration (μg/m3)

2013 2014 2015

JB4 JB5 JB4 JB5 JB4 JB5

Annual mean concentration 13.4 17.3 11.3 20.0 12.3 15.9

24-hour high concentration 81.7 90.0 68.5 134.1 134.5 116.1

24-hour 2nd highest concentration 67.4 89.1 63.4 134.0 101.9 78.0

Source: IML Air Science (2013, 2014, 2015)

These concentrations are in compliance with the PM10 NAAQS (150 μg/m3 highest 24-hour average) and 

PM10 WAAQS (150 μg/m3 highest 24-hour average and 50 μg/m3 annual mean). If elevated PM10 readings 

are detected at JB4 and JB5, BCC would implement the contingency action plan for high particulate 

levels.

HAP emissions are not required to be tracked at the Bridger Mine Complex.

The Proposed Action would be covered under the Bridger Mine Complex’s existing air permits and 

would be subject to the same limitations and requirements. No permit modification would be required.

3.3.2.3. JIM BRIDGER POWER PLANT 

The Jim Bridger Power Plant, a coal-fired power station, is located in the analysis area and is classified as 

a major source. Coal is transported from the Bridger Mine Complex by overland conveyor to the Jim 

Bridger Power Plant. Coal-fired power plants emit criteria pollutants, HAPs, and other toxic air 

pollutants. Two notable problems associated with such air pollutant emissions are acid and mercury 

deposition. Coal-fired power plants can contribute to acid deposition through SO2 and NOx emissions. 

When acid chemicals are incorporated into rain, snow, fog, mist, dust, or smoke, some of the pollution 

falls to the ground as acid deposition. Atmospheric deposition of air pollutants can increase the acidity of 

soil and water resources. Coal-fired power plants can also contribute to mercury deposition. When 

mercury is deposited on land and water, it accumulates in the food chain and can be toxic to fish, wildlife, 

and humans. Coal combustion is also a potential source of trace element emissions, including arsenic, 

barium, boron, cadmium, chromium, lead, molybdenum, and selenium. Increasing concern about the 

effects of trace pollutants on the environment has led to the introduction of emission standards for some 

of these elements.

The Jim Bridger Power Plant operates under a 2005 Title V Operating Permit No. 3-1-120-2 (WDEQAQD 2005). A number of amendments or waivers to the operating permit have been issued for equipment 

modifications and updates, process changes, and for pollution control projects. The plant also operates 
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under WDEQ-AQD air permit MD-12186, dated 2011, which contains emission limitations and other 

requirements for the plant’s coal-burning boilers. The Jim Bridger Power Plant has a startup and 

shutdown emission minimization plan, as well as a water spray operations plan for dust emissions.

In 2011, the EPA finalized national standards (the Mercury and Air Toxics Standards) to reduce air 

pollution from coal- and oil-fired power plants. These rules set emission limitation standards for mercury 

and other toxic air pollutants such as arsenic, chromium, nickel, and acid gases (e.g., hydrochloric acid 

and hydrofluoric acid). The final rule sets standards for all HAPs emitted by coal- and oil-fired electric 

generating units with a capacity of 25 megawatts or greater. The Jim Bridger Power Plant is subject to 

these standards.

On September 2015, the EPA’s SO2 data requirements rule for the 2010 1-hour SO2 primary NAAQS 

became effective. This rule directs state agencies to characterize current air quality in areas with large 

sources of SO2 emissions to identify maximum concentrations in ambient air. The Jim Bridger Power 

Plant is subject to this rule and will operate an SO2 monitoring station to meet the rule requirements. The 

WDEQ-AQD is currently evaluating locations for the SO2 monitor. 

Section 169A of the CAA directs states to evaluate the use of retrofit controls at specific larger, older 

stationary sources to address visibility impacts. Certain categories of sources must install and operate Best 

Available Retrofit Technology (BART) as determined by the State. Wyoming’s State Implementation 

Plan establishes BART requirements for NOx emission controls for power plant units in the state, 

including the Jim Bridger Power Plant. Under Wyoming’s long-term strategy, low NOx burners with 

separated overfire air are required on all four boilers at the plant. In addition, a 2010 BART appeal 

settlement agreement between WDEQ-AQD and PacifiCorp requires the installation of additional NOx

controls at the Jim Bridger Power Plant. The plant operates under BART permit MD-6040A2, dated 

2010, which sets NOx emission limits.

The Jim Bridger Power Plant would also be subject to the new Clean Power Plan Final Rule (Carbon 

Pollution Emission Guidelines for Existing Stationary Sources: Electric Utility Generating Units) 

announced on August 3, 2015, and plans to address all requirements under the rule (Childs et al. 2015). 

Implementation of the rule was stayed by the Supreme Court on February 9, 2016. 

The primary emission sources at the Jim Bridger Power Plant are four tangentially fired coal-burning 

boilers. The four boilers were initially equipped with early low-NOx burners to control emissions of NOx. 

The early low-NOx burners have been updated with new, modern low-NOx burners, each with overfire air. 

Each boiler is also equipped with a dry electrostatic precipitator to control PM emissions; SO2 emissions 

from each unit are controlled using a wet sodium flue gas desulfurization system. Selective catalytic 

reduction (SCR) was installed on the Unit 3 boiler in December 2015, and was scheduled to be installed 

on the Unit 4 boiler by December 2016. The plant must also install SCR or other NOX emission controls 

on the Unit 2 boiler by the end of the year 2021 and the Unit 1 boiler by the end of 2022. The Jim Bridger 

Power Plant submitted an air operating permit application to the WDEQ-AQD on March 21, 2016, to 

revise their operating permit to include the new emission control technology. The new control technology 

will also help reduce mercury emissions. 

The permit application for revision of the operating permit quantified the Jim Bridger Power Plant’s 

potential to emit the following HAPs and toxic air pollutants:

Mercury: 0.03 ton per year from each of the four boilers (0.12 ton per year total) 

Sulfuric acid: 105.1 tons per year from each of the four boilers (420.4 tons per year total)

Hydrofluoric acid: 9.0 tons per year from each of the four boilers (36.0 tons per year total)

Ammonia: 133.2 tons per year from each of two of the four boilers (266.4 tons per year total) 
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A summary of other emissions from the Jim Bridger Power Plant is included here to provide context and 

to assist with analysis of the combustion of coal mined from the project area. Table 3-6 summarizes the 

Jim Bridger Power Plant’s 2015 annual emission inventory data. 

Table 3-6. Jim Bridger Power Plant 2015 Emissions Inventory

Pollutant Emissions (tons per year)

CO 5,007

NOx 13,704

PM10 705

PM2.5 221

PM 1,400

SO2 10,265

VOCs 228

HAPs 145

Ammonia 2.5

Note: The HAPs total includes emissions for 73 individual HAPs. 

Source: PacifiCorp (2015a).

Some of the individual HAP totals quantified by the 2015 emission inventory include:

Mercury: 187.6 pounds (lbs) per year 

Sulfuric acid: 88.3 tons per year 

Hydrofluoric acid: 28.7 tons per year

Acetaldehyde: 441.9 lbs per year 

Acrolein: 262.2 lbs per year 

Arsenic: 94.2 lbs per year 

Benzene: 538.8 lbs per year 

Cadmium: 25.4 lbs per year 

Chromium: 292.2 lbs per year 

Formaldehyde: 363.0 lbs per year 

Selenium: 340.2 lbs per year 

Xylene: 174.0 lbs per year 

Annual coal throughput at the Jim Bridger Power Plant in 2015 was 7,613,893 tons (the annual permitted 

throughput is 9,500,000 tons) (PacifiCorp 2015b). In 2015, coal for the power plant was supplied by 

Black Thunder Mine, Black Butte Mine, and the Bridger Mine Complex. 

Coal-fired power plants such as the Jim Bridger Power Plant create coal combustion residues or wastes 

(CCW), which consist of inorganic residues that remain after pulverized coal is burned. The different 

types of CCW are bottom ash (inert slag formed during combustion), fly ash (fine PM removed from the 

gas stream prior to venting), flue gas desulphurization products (precipitate formed during chemical 

removal of SO2 prior to venting), and boiler slag (ash collected from the base of certain furnaces 

quenched with water) (Luther 2010). CCW are typically contained either in surface impoundments or 
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landfills. Landfills are used where the power plant adopts a dry disposal of its CCW. When a power plant 

adopts a wet disposal, the CCW are slurried and piped to a surface impoundment (Solmax International 

2012). Some CCW are put to beneficial use in other ways, such as a component in concrete, structural fill, 

or road-base materials (Luther 2010). At the Jim Bridger Power Plant, CCW are disposed of in the Jim 

Bridger Industrial Landfill and the Jim Bridger Flue Gas Desulphurization (FGD) Ponds 1 and 2. FGD 

Pond 1 is no longer in operation and is undergoing closure. 

CCW typically contain a range of heavy metals such as arsenic, lead, selenium, mercury, and chromium, 

which can be hazardous to human health and the environment. The primary concern regarding the 

management of CCW is the potential for hazardous constituents to leach into surface or groundwater 

through unlined CCW surface impoundments or landfills and contaminate drinking water, surface water, 

or living organisms. The EPA has determined that arsenic, lead, and other carcinogens have leached into 

groundwater and exceeded safe limits when CCW is disposed of in unlined disposal units, presenting 

substantial risks to human health and the environment (Luther 2010; Tan et al. 2012). There are complex 

physical and biogeochemical factors that influence the degree to which heavy metals can dissolve and 

migrate off-site, including the mass of toxins in the waste and the degree to which water can flow through 

the waste (Luther 2010). Additional concerns regarding the management of CCW are the blowing of 

contaminants into the air as dust and the catastrophic failure of surface impoundments.

The EPA published a final rule in April 2015 on the disposal of coal combustion residuals from electric 

utilities. Prior to this rule, CCW were only subject to state requirements. The rule provides a 

comprehensive set of requirements for the safe disposal of CCW and establishes technical specifications 

for CCW landfills and surface impoundments under subtitle D of the Resource Conservation and 

Recovery Act. The rule also sets out recordkeeping and reporting requirements and supports the 

responsible recycling of CCWs by distinguishing safe, beneficial use from disposal. State solid waste

management plans, approved by the EPA, serve as mechanisms for States to detail how they intend to 

regulate CCW landfills and surface impoundments as part of their overall solid waste program.

As part of a national program to assess the management of CCW, the EPA conducted a specific site 

assessment of the dam safety of FGD Ponds 1 and 2 embankment dams at the Jim Bridger Power Plant in 

June 2009. FGD Pond 1 first went into service in 1979, and FGD Pond 2 first went into service in 1990. 

The assessment indicated that there were no known spills or unpermitted releases for either pond in the 

last 10 years. Typically, 90% of the generated fly ash at the Jim Bridger Power Plant is sold commercially 

for use in concrete. Waste bottom ash is dewatered and disposed of in the industrial landfill. Water-borne 

combustion waste that consists primarily of FGD solids is pumped from the plant via two aboveground 

pipes around FGD Pond 1 (which is undergoing closure) to an inlet structure for FGD Pond 2. Both pond 

embankments were generally found to be in satisfactory condition by the assessment, with acceptable 

maintenance and surveillance programs. Minor corrective measures for the structures were recommended 

(GEI Consultants, Inc. 2009).

3.3.3. Climate Change

Global warming refers to the ongoing rise in global average temperature near the Earth's surface. It is 

caused mostly by increasing concentrations of GHGs (primarily CO2, methane, nitrous oxide (N2O), and 

fluorinated gases) in the atmosphere, and it is changing climate patterns. Climate change refers to any 

significant change in the measures of climate (e.g., temperature, precipitation, and wind patterns) lasting 

for an extended period of time (EPA 2016e). In 2010, the National Research Council concluded that

“climate change is occurring, is caused largely by human activities, and poses significant risks for a broad 

range of human and natural systems” (National Research Council 2010:1).
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Carbon dioxide is the primary GHG emitted through human activities that contributes to climate change 

(81% of total United States GHG emissions in 2014); it is followed by methane (11% of total 2014 

emissions), N2O (6% of total 2014 emissions), and fluorinated gases (3% of total 2014 emissions) (EPA 

2016f). The main human activity emitting CO2 is the combustion of fossil fuels (including the combustion 

of coal) for energy and transportation (EPA 2016g). 

In May 2014, the U.S. Global Change Research Program released Climate Change Impacts in the United 

States: The Third National Climate Assessment (Assessment), a comprehensive report on climate change 

and its impacts in the United States (Melillo et al. 2014). In the Assessment, the Great Plains region 

comprises the states of Montana, Wyoming, North Dakota, South Dakota, Nebraska, Kansas, Oklahoma, 

and Texas. According to the Assessment, projections suggest more frequent and more intense droughts, 

severe rainfall events, and heat waves in this region. High temperatures are projected to occur much more 

frequently. Key climate change highlights for the Great Plains region include the following, excerpted 

directly from the Assessment:

Rising temperatures are leading to increased demand for water and energy. In parts of the 

region, this will constrain development, stress natural resources, and increase competition for 

water among communities, agriculture, energy production, and ecological needs. 

Landscape fragmentation is increasing, for example, in the context of energy development 

activities in the northern Great Plains. A highly fragmented landscape will hinder adaptation of 

species when climate change alters habitat composition and timing of plant development 

cycles.

Communities that are already the most vulnerable to weather and climate extremes will be 

stressed even further by more frequent extreme events occurring within an already highly 

variable climate system.

The magnitude of expected changes will exceed those experienced in the last century. Existing 

adaptation and planning efforts are inadequate to respond to these projected impacts. (Melillo et

al. 2014) 

Specifically in Wyoming, most of the state has warmed by 1 to 3 degrees Fahrenheit over the past century 

(EPA 2016h). Heat waves are becoming more common and snow is melting earlier in the spring. The 

snowpack has been decreasing since the 1950s. The changing climate will likely decrease the availability 

of water in Wyoming, affect agricultural yields, and increase the risk of wildfires. By 2050, Wyoming is 

likely to have twice as many days above 100 degrees Fahrenheit as it does today (EPA 2016h). 

Coal combustion for electric power and industry produces CO2 emissions, in addition to non-GHG 

pollutants such as SO2, NOX, PM, mercury, and other heavy metals. Coal mining, particularly 

underground mining, produces methane, which is created during coal formation and is released from the 

coal seam and the surrounding rock strata. The term carbon dioxide equivalent (CO2e) is used to describe 

different GHGs in a common unit. For any quantity and type of GHG, CO2e represents the amount of CO2

that would have the equivalent global warming impact (Brander 2012). In 2014, U.S. fossil fuel 

combustion resulted in emissions of 5,208.2 million metric tons of CO2e and coal mining resulted in 

emissions of 67.6 million metric tons of CO2e (compared to total emissions of 6,870.5 million metric tons 

of CO2e) (EPA 2016i). In Wyoming, energy-related CO2 emissions from coal were 49.2 million metric 

tons in 2013 (out of a total of 68.4 million metric tons of energy-related total CO2 emissions in the state) 

(EPA 2015a).

The EPA regulates GHG emissions under several initiatives, including the Mandatory Greenhouse Gas 

Reporting rule, the Final Greenhouse Gas Tailoring Rule, geologic sequestration requirements, and EPA 

and National Highway Traffic Safety Administration standards for new motor vehicles. Under the 

Mandatory Greenhouse Gas Reporting rule (40 CFR 98), coal mines subject to the rule are required to 
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report emissions in accordance with the requirements of Subpart FF. Subpart FF is applicable only to 

underground coal mines and would not apply to the Proposed Action. Because no change to emissions 

would occur under the Proposed Action, no other GHG reporting or permitting requirements would apply. 

3.4. Cultural Resources 

Cultural resources are evidence of past human activity. They can be either prehistoric or historic in age 

(i.e., dating to either before or after the time of Euro-American settlement), and they include artifacts 

(portable objects of human manufacture such as tools); features such as fire pits, houses, earthworks, and 

other types of structures; human burial sites; art; trails; and archaeological sites where any of the above 

may be found. Cultural resources can also include other types of places that are important to the heritage 

of contemporary peoples (e.g., sacred and traditional cultural properties).

Cultural resources are managed under a variety of laws and regulations, including Section 106 of the 

National Historic Preservation Act of 1966 (NHPA) (36 CFR 800). This section requires that federal 

agencies take into account the effect that a federal undertaking may have on historic properties—that is, 

any district, site, building, structure, or object that is included in or eligible for the National Register of 

Historic Places (NRHP). 

The analysis area for impacts to cultural resources is the 560-acre project area. This is the area of 

potential effects for purposes of review under Section 106 of the NHPA. 

3.4.1. Cultural Context 

The project area lies in an expanse of Wyoming that is an elevated structural plain (the Wyoming Basin) 

located between the Great Plains to the east, the Great Basin to the west and southwest, and the Columbia 

Plateau to the northwest. This area served as a natural travel corridor between surrounding cultural areas, 

with outside groups passing through the region and interacting with the indigenous population. In 

addition, the local indigenous population adapted to local environmental conditions. Consequently, a 

variety of unique cultural manifestations over time are present in the Wyoming Basin (BCC 2016). 

A chronology for the Wyoming Basin has been developed based on the frequency of radiocarbon dates 

from southwest Wyoming (BCC 2016). The chronology defines six phases: 

Pre-Paleoindian Period (pre-12,000 B.P.): Recent evidence suggests that South America has been 

inhabited for more than 13,000 years. There are also claims suggesting that some form of preClovis or generic pre-Paleoindian populations occupied the New World prior to the well-known 

Paleoindian groups. However, there is currently no firm evidence for the early occupation of the 

western Wyoming Basin.

Paleoindian Period (12,000–8200 B.P.): Archaeological evidence for this period suggests a 

specialized hunting subsistence strategy based on megafauna such as bison. The lithic technology 

of this period is distinctive for its meticulous workmanship, especially on projectile points which 

are usually lanceolate.

Archaic Period (8200–1800 B.P.): Aboriginal subsistence methods became more diverse in 

response to climatic change, resulting in a proliferation of technological traditions. The lanceolate 

projectiles of the Paleoindian Period were replaced with smaller side-and corner-notched atlatl 

dart points. Other evidence suggests increased use of vegetable resources and increased 

procurement of small animals.
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Late Prehistoric Period (begins 2000 B.P.): This period begins with the introduction of the bow 

and arrow and pottery, and ends when European culture begins to influence the area 

approximately 300 years ago. Pottery first appears approximately A.D. 650. Evidence suggests 

that a wide variety of plant foods were utilized, as well as larger animals such as antelope and 

bison. 

Protohistoric Period (begins A.D. 1700–1750): The Protohistoric Period begins when the first 

European trade goods arrive, and ends in the early 1800s with the appearance of Euro-Americans 

associated with the Rocky Mountain fur trade. The most profound influence on Native cultures 

during this time was the introduction of the horse in the early 1700s, which improved mobility, 

increased the efficiency of hunting, and allowed for better transportation of material culture. 

Historic Period (begins in the early A.D. 1800s): This period begins with the Lewis and Clark 

expedition of the Missouri River in 1805–1806. The Rocky Mountain fur trade developed rapidly, 

with dramatic changes in traditional Indian lifeways. Traditional aboriginal subsistence strategies 

became increasing difficult with the intensified competition over game and land. The Union 

Pacific Railroad reached the Wyoming Basin in 1868, and the effective end of aboriginal 

occupation of the Wyoming Basin occurred the same year, with the removal of the resident 

Shoshone to the Wind River Reservation. Stage roads and other expansion-era roads were 

constructed after the railroad reached southwest Wyoming. After 1868, cow and sheep camps 

were established with the development of the livestock industry (BCC 2016). 

3.4.2. Known Cultural Resources

The Bridger Mine Complex has been the focus of multiple archaeological investigations, beginning with 

initial Class III surveys by the Office of the Wyoming State Archaeologist in 1976. Most of the studies 

have been conducted for BCC and the Jim Bridger Power Plant and have included block inventories and 

studies connected to roads, power lines, core holes, and other projects associated with mining activities. 

Small inventories for well pads, natural gas pipelines, and roads have also been conducted on the 

periphery of the Bridger Mine Complex permit area (Western Archaeological Services [WAS] 2009).

3.4.2.1. SECTION 12 OF THE PROJECT AREA

A Class III cultural resource inventory was conducted by WAS in 2009 on a larger study area that 

included the portion of Section 12 in the project area (WAS 2009). The objectives of the inventory were 

to provide a complete record of cultural properties identifiable from surface and natural exposures in the 

study area and to determine the relationship of the cultural resources to the proposed mine disturbance 

area. An intensive pedestrian survey was conducted. Portions of Section 12, as well as the larger WAS 

study area, had previously been inventoried for cultural resources. The WAS 2009 cultural resource 

inventory resulted in the discovery of five new sites, nine previously recorded sites, and four isolated 

artifacts. All of the new and previously recorded sites are located in Section 12; two of the isolated 

artifacts are located in Section 12. None of these sites are eligible for nomination to the NRHP. The 

cultural resource inventory indicated that there is a low potential for encountering intact buried cultural 

remains within the residual soils and shallow sands in the study area. No further action was recommended 

(WAS 2009). 

Following submission of the 2009 Class III cultural resource inventory report, the BLM Rock Springs 

Field Office identified a segment of 48SW3860, Cherokee Trail, Evans Variant, in the study area 

(Segment 1). In 2010, WAS evaluated the trail segment in the study area to determine whether it retained 

sufficient integrity to contribute to the NRHP eligibility of the Cherokee Trail (WAS 2010). The physical 

and visual integrity of the trail segment was assessed. The Evans Variant of the Cherokee Trail is one of 

two variants of the trail that led west from the Indian Territory of modern-day Oklahoma to the gold fields 
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of California (WAS 2010). The route was first used in 1849 and crosses the south half of Section 12 and 

runs northeast to southwest. In Section 12, it consists of an upgraded, flat, bladed, or crown-and-ditch 

road. Modern culverts are present in the larger tributary drainage crossings and modern construction was 

noted at the western end of the segment. The road was upgraded sometime in the past but has not been 

recently maintained. The setting has been extensively affected by ongoing mining activities (WAS 2010).

The Cherokee Trail has been previously determined eligible for the NRHP by the Wyoming State Historic 

Preservation Officer. Segment 1 of the portion recorded by the BLM Rock Springs Field Office is 

evaluated as non-contributing to the overall NRHP eligibility of the Cherokee Trail (WAS 2010). The 

trail segment has been completely destroyed by modern road construction activities and consists entirely 

of an upgraded road. No intact trail remains were observed. The trail segment does not retain physical 

integrity and the setting does not contribute to its NRHP eligibility. No significant trail remains would be 

affected by proposed mining activities and no further work is recommended (WAS 2010).

3.4.2.2. SECTION 24 OF THE PROJECT AREA

A Class III cultural resource inventory was conducted in 2008 on a larger study area that included the 

portion of Section 24 in the project area (WAS 2008). The objectives of the inventory were to provide a 

complete record of cultural properties identifiable from surface and natural exposures in the study area 

and to determine the relationship of the cultural resources to the proposed mine disturbance area. An 

intensive pedestrian survey was conducted. The file search indicated that three previous projects have 

been conducted in Section 24, covering 109 acres. Of this total, 80 acres overlapped the WAS study area. 

One previously recorded site (48SW13859) was identified in the portion of Section 24 that is in the 

project area. A second previously recorded site (48SW6061) was identified in the portion of Section 24 in 

the project area; however, WAS found this site to be 200 feet east of the project area boundary (WAS 

2008). No newly identified cultural resource sites were in the project area. 

Site 48SW13859 (Bitter Creek NW 153) is located on a tributary of Tenmile Draw and was originally 

recorded in August 2001. At that time, it consisted of a scatter of historical debris, including wire nails, 

wood scraps, small pieces of coal, six food cans, a flat tobacco tin, a condensed milk can, three seam 

cans, and a probable wagon part. The site was revisited during the WAS cultural resource inventory and 

the same scatter of debris was noted. The artifacts date to the mid-twentieth century and likely reflect a 

sheep camp. The cultural resource inventory indicated that buried material remains are highly unlikely 

given the age and use of the site. The site is recommended not eligible for the NRHP (sheep camps 

contribute little to our understanding of sheep raising or the early economic development of Wyoming’s 

livestock industry) (WAS 2008).

Site 48SW6061 is an open camp that has been determined eligible for the NRHP. Because of its location 

200 feet east of the inventory area, it would not be affected by surface disturbance and no further work 

was recommended (WAS 2008).

Also present nearby are the Overland Trail (48SW1226) and the Point of Rocks to South Pass State Road 

(48SW386), both of which are NRHP-eligible historic properties. The Overland Trail is located 6.5 miles 

southwest and the Point of Rocks stage road is located 5 miles west of the WAS study area. Both 

properties and the WAS study area are covered by a Memorandum of Agreement (MOA) between the 

BLM and the Wyoming State Historic Preservation Office (WAS 2008). The MOA states that those 

segments of the Overland Trail and State Road that are covered by the MOA do not contribute to the 

visual integrity of the historic properties due to modern developments such as roads, power lines, and the 

Bridger Mine Complex. No visual impacts to the Overland Trail or the Point of Rocks to South Pass State 

Road would result from the proposed mine disturbance (WAS 2008). 
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3.4.3. Native American Religious Concerns 

A scoping letter was sent on June 1, 2016, to the following Native American tribes to identify any Native 

American religious concerns or other issues with the Proposed Action: 

Shoshone-Bannock Tribes (Fort Hall Reservation, Idaho) 

Eastern Shoshone Tribe (Wind River Reservation, Wyoming) 

Northern Arapahoe Tribe (Wind River Reservation Wyoming)

Northern Ute Tribe (Uintah and Ouray Reservation, Utah)

The scoping letter requested comments on the Proposed Action and continued consultation with the tribes 

for the stages of proposal development and implementation of the final federal action. No cultural or 

religious concerns or Traditional Cultural Properties have been identified through consultation with the 

tribes.

3.5. Fish and Wildlife

The impact analysis area for fish and wildlife is the project area with a 0.5-mile buffer. This area was 

chosen because it provides a reasonable boundary for analysis of the potential direct and indirect impacts 

to wildlife and wildlife habitat from the proposed surface mining activities.

3.5.1. Common Wildlife

The landscape in the wildlife impact analysis area supports Wyoming big sagebrush (Artemisia tridentata 

var. wyomingensis) and/or big sagebrush (Artemisia tridentata var. tridentata), yellow rabbitbrush 

(Chrysothamnus viscidiflorus), rubber rabbitbrush (Ericameria nauseosa), Gardner’s saltbush (Atriplex 

gardneri) and/or mat saltbush (Atriplex corrugata), and bud sagebrush (Picrothamnus desertorum). A 

majority of the analysis area is covered by either the Inter-Mountain Basins Big Sagebrush Shrubland or 

Inter-Mountain Basins Mixed Salt Desert Scrub land cover types. Wildlife species that are commonly 

associated with these vegetation and land cover types include species such as coyotes, red fox, prairie 

dogs, ground squirrels, white-tailed jackrabbits, desert cottontails, various game and non-game birds, 

reptiles, amphibians, etc.

3.5.2. Big Game

As discussed in the 2010 Bridger Lease Modification EA, the wildlife impact analysis area offers yearround habitat for many big-game species, such as pronghorn antelope, elk, and mule deer. Table 3-7 lists 

the acres of mule deer, elk, and pronghorn antelope habitat in the wildlife impact analysis area. Figures 

3-2, 3-3, and 3-4 show the locations mule deer, elk, and pronghorn antelope habitat in the wildlife impact 

analysis area. 

Table 3-7. Acres of Big-Game Habitat in the Fish and Wildlife Impact Analysis Area

Habitat Type Acres

Mule deer winter/year-long 3,323.2

Elk year-long 3,323.2

Pronghorn antelope crucial, winter/year-long 2,477.3

Pronghorn antelope winter/year-long 845.9
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Figure 3-2. Mule deer habitat in the fish and wildlife impact analysis area.
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Figure 3-3. Elk habitat in the fish and wildlife impact analysis area.
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Figure 3-4. Pronghorn antelope habitat in the fish and wildlife impact analysis area.
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3.5.3. Migratory Birds, including Raptors

As discussed in the 2010 Bridger Lease Modification EA, the BLM interdisciplinary team determined that 

the fish and wildlife impact analysis area contains suitable ferruginous hawk nesting and foraging habitat, 

such as basin-prairie shrub, grassland, and rock outcrops. Ferruginous hawks are a BLM sensitive species 

and are managed to ensure that BLM actions do not result in the listing of the species under the 

Endangered Species Act. Table 3-8 lists migratory birds that occur in Sweetwater County, Wyoming. 

Other migratory birds that are associated with the vegetation types found in the fish and wildlife impact 

analysis area include Gambel’s quail (Callipepla gambelii), Brewer’s sparrow (Spizella breweri), sage 

sparrow (Amphispiza belli), mountain bluebird (Sialia currucoides), green-tailed towhee (Pipilo

chlorurus), and sage thrasher (Oreoscoptes montanus).

Annual raptor nest surveys are currently conducted by BCC within the permit area and in areas of raptor 

concentration near the permit area. All previously located nests are monitored each spring, with searches 

of new nest sites conducted throughout the study area. Methodologies for raptor monitoring follow those 

described in WDEQ-LQD Coal Rules and Regulations, Appendix B. Nest status and production success 

is reported in an annual report. According to BCC’s 2014 Annual Report (BCC 2014b), nine species of 

raptors potentially nest within the permit area and in areas of raptor concentration near the permit area. 

Eight of these species nested or were observed on territories through the nesting season during the 2014 

report period: golden eagle, red-tailed hawk, ferruginous hawk, northern harrier, prairie falcon, American 

kestrel, burrowing owl, and great horned owl. The predominant substrates for nesting raptors were cliffs, 

rock pedestals, rocky outcrops, spoil piles, and highwalls. Four species used mine-created habitat, such as 

highwall, truck dump station hoppers, the interior of the dragline, and platforms. Raptor productivity in 

2014 showed an increase for almost all species compared to 2013. Total occupied territories and 

reproductive nests were both up, and the number of successful nests increased. Fledgling success and the 

overall number of young fledged also increased.

BCC currently monitors Migratory Birds of High Federal Interest opportunistically and on the northern 

road route during the nesting season. Any observations of Migratory Birds of High Federal Interest are 

recorded and reported as required in WDEQ-LQD Coal Rules and Regulations, Appendix B.

Table 3-8. Migratory Birds with Potential to Occur in or near the Fish and Wildlife Impact Analysis Area

Common Name Scientific Name Season Potential to Occur in the Wildlife Impact Analysis Area

American bittern Botaurus lentiginosus Breeding USFWS habitat data indicate that there is potential for this 

species to occur in the analysis area.

Bald eagle Haliaeetus leucocephalus Year-round USFWS habitat data indicate that there is potential for this 

species to occur in the analysis area. However, there are no 

bald eagle roosts on or within 1 mile of BCC’s existing permit 

boundary.

Black rosy-finch Leucosticte atrata Year-round USFWS habitat data indicate that there is potential for this 

species to occur in the analysis area.

Brewer’s sparrow Spizella breweri Breeding USFWS habitat data indicate that there is potential for this 

species to occur in the analysis area.

Burrowing owl Athene cunicularia Breeding USFWS habitat data indicate that there is potential for this 

species to occur in the analysis area.

Cassin’s finch Carpodacus cassinii Year-round USFWS habitat data indicate that there is potential for this 

species to occur in the analysis area.

Ferruginous hawk Buteo regalis Year-round USFWS habitat data indicate that there is potential for this 

species to occur in the analysis area.
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Common Name Scientific Name Season Potential to Occur in the Wildlife Impact Analysis Area

Fox sparrow Passerella iliaca Breeding USFWS habitat data indicate that there is potential for this 

species to occur in the analysis area.

Golden eagle Aquila chrysaetos Year-round USFWS habitat data indicate that there is potential for this 

species to occur in the analysis area.

Greater sage-grouse Centrocercus 

urophasianus

Year-round USFWS habitat data indicate that there is potential for this 

species to occur in the analysis area.

Loggerhead shrike Lanius ludovicianus Year-round USFWS habitat data indicate that there is potential for this 

species to occur in the analysis area.

Long-billed curlew Numenius americanus Breeding USFWS habitat data indicate that there is potential for this 

species to occur in the analysis area.

Mountain plover Charadrius montanus Breeding USFWS habitat data indicate that there is potential for this 

species to occur in the analysis area. However, surveys in the 

summer and fall of 2000 found very little, if any, suitable 

mountain plover nesting habitat in BCC’s mine permit 

boundary. Negative habitat indicators predominate. No 

sightings of mountain plovers have been documented within 

the permit boundary during 24 years of monitoring. Therefore, 

no further discussion of this species is included in this EA.

Olive-sided 

flycatcher

Contopus cooperi Breeding USFWS habitat data indicate that there is potential for this 

species to occur in the analysis area.

Pinyon jay Gymnorhinus 

cyanocephalus

Year-round USFWS habitat data indicate that there is potential for this 

species to occur in the analysis area.

Sage thrasher Oreoscoptes montanus Breeding USFWS habitat data indicate that there is potential for this 

species to occur in the analysis area.

Short-eared owl Asio flammeus Year-round USFWS habitat data indicate that there is potential for this 

species to occur in the analysis area.

Snowy plover Charadrius alexandrinus Breeding USFWS habitat data indicate that there is potential for this 

species to occur in the analysis area.

Swainson’s hawk Buteo swainsoni Breeding USFWS habitat data indicate that there is potential for this 

species to occur in the analysis area.

Western grebe Aechmophorus 

occidentalis

Breeding USFWS habitat data indicate that there is potential for this 

species to occur in the analysis area.

Willow flycatcher Empidonax traillii Breeding USFWS habitat data indicate that there is potential for this 

species to occur in the analysis area.

Source: USFWS (2016). 

The northern portions of the existing Bridger Mine Complex, Section 12, and a small portion of the 

northeast corner of Section 24 are within the identified State of Wyoming’s Core Population Areas for 

greater sage-grouse. However, the Wyoming Governor’s Sage-Grouse Implementation Team refined the 

boundaries to remove the existing mine and the adjacent parcels (including Sections 12 and 24) from the 

Core Population Areas because of the lack of healthy sagebrush habitat within the mining areas that are 

suitable for sage-grouse (WGFD 2016).

BCC currently conducts intensive sage-grouse strutting surveys each spring to ensure documentation of 

any future sage-grouse strutting conflicts associated with the Bridger Mine Complex. Lek searches and 

lek attendance surveys follow methodologies described in WDEQ-LQD Coal Rules and Regulations, 

Appendix B. Male peak counts and linear distance from each lek to the closest known mine disturbance 

are reported in an annual report. According to BCC’s 2014 Annual Report (BCC 2014b), there are five 

active leks within 5 miles of existing mining disturbance. The closest of these leks is the Black Rock 

Satellite A lek, which is approximately 1.6 miles away from existing mining disturbance. In addition to 

strutting surveys, BCC works with the WGFD and other state agencies to voluntarily implement 

stipulations and mitigation practices on a case-by-case basis.
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3.5.4. Fish

All of the streams in the fish and wildlife impact analysis area are ephemeral or intermittent streams that 

are unlikely to support fish populations. The WGFD does not require BCC to monitor impacts to fish in 

its annual reports.

3.6. Geology and Minerals

The impact analysis area for geology and minerals is the 560-acre mining plan modification area. This 

area was chosen because potential impacts to geology and minerals from the Proposed Action would not 

extend beyond the surface disturbance related to the proposed mining activities.

3.6.1. Geology

The Jim Bridger coalfield is located on the northeastern flank of the Rock Springs Uplift, a 34-mile-wide 

by 60-mile-long asymmetrical anticlinal structure that separates the Green River Basin on the west and 

the Great Divide/Washakie Basins on the east. The coalfield is approximately 15 miles long and 2 miles 

wide. The coal seams in the Jim Bridger area occur in the lowermost Paleocene Fort Union Formation, in 

the “Black Rock Coal Groups.” The beds generally dip 2 to 5 degrees to the northeast. The entire project 

area overlies the Fort Union Formation. A stratigraphic column for the mine permit area is shown in 

Figure 3-5. The Cumulative Hydrologic Impact Assessment of Coal Mining in the Greater Green River 

Basin, Southwestern Wyoming (CHIA; WDEQ-LQD 2014) provides several maps and figures depicting 

the surface and subsurface geology of the region (see Figures 2, 3, 4, and 5 of the CHIA).

The Rock Springs Uplift has a north-trending major axis. The dip of strata on its flanks is generally 

between 3 and 15 degrees toward the adjacent structural lows. Precambrian rocks on the apex of the uplift 

are estimated to be 17,000 feet above the Precambrian rocks in the Green River and Washakie Basins. 

Normal faults with generally less than 100 feet vertical displacement cut through the Rock Springs Uplift. 

The Deadman Coal Zone of the Fort Union Formation is approximately 60 to 80 feet above the contact 

with the underlying Lance Formation. The Fort Union Formation is approximately 1,500 feet thick in the 

Jim Bridger area, and the Lance Formation is approximately 900 feet thick.

The surface geology in the project area includes approximately 247 acres of residuum mixed with eolian 

deposits, 159 acres of residuum mixed with slope wash and eolian deposits, and 153 acres of eolian 

deposits and residuum with minor bedrock outcrops. The surface geology in the project area is shown on 

Figure 3-6.
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Figure 3-5. Stratigraphic column for the mine permit area.
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Figure 3-6. Surface geology in the project area.
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3.6.1.1. GEOLOGIC HAZARDS

The Jim Bridger coalfield is located in Seismic Zone 1 (Uniform Building Code), an area of low seismic 

risk and minimal potential for earthquake activity. Faults that are apparently younger than those within 

the coalfield are located about 40 miles to the north. These high-angle normal faults, named the 

Continental and Flattop faults, are approximately 25 to 45 miles in length, and were apparently last active 

in the late Cenozoic period.

3.6.2. Minerals

There are five seams of coal in the Jim Bridger Coal Field within the Deadman Coal Zone. The seams are 

designated D-5 through D-1, from top to bottom. Coal seam thicknesses vary throughout the field. 

Average coal thicknesses for the various seams are listed in Table 3-9. In the north-central portion of the 

mine area, the five seams join together to form a single seam with a maximum thickness of 32 feet. The 

seams divide into two coal seams (D-5 and D-4 through D-1) toward the northwest and northeast. The 

single seam divides into two seams (D-5/D-4 and D-3 through D-1) toward the southeast. Further to the 

southeast, both of these coal seams divide once again, forming a total of four seams (D-5, D-4, D-3, and 

D-2/D-1) from 2 to 15 feet thick. Coal in the Jim Bridger coalfield is typically ranked in a range from 

subbituminous A to subbituminous B.

Table 3-9. Average Thickness of Coal Seams in the Jim Bridger Coal Field

Seam Average Thickness (feet)

D-5 5

D-4 8

D-3 4

D-2 3

D-1 4

The major sedimentary units of the Fort Union Formation in the Bridger Mine Complex permit area are 

sandstone, siltstone, claystone, and coal. These units interbed and interfinger, forming a complex 

stratigraphic section that is characteristic of coal-bearing sequences in the western United States. The 

lithology of stratigraphic sections and the lateral continuity of sedimentary units are quite variable. The 

proportions and stratigraphic position of sandstone, siltstone, and claystone that form the overburden also 

differ considerably from one area of the Bridger Mine Complex to another. Often these differences are 

quite substantial and occur over a distance of only a few feet to several hundred feet. 

3.7. Socioeconomics

The analysis area for impacts to socioeconomics is Sweetwater County, Wyoming. This area was chosen 

because the economic and demographic effects of the Proposed Action would likely be experienced by 

the surrounding communities in the county. This area is where most of the employees of proposed mining 

operations on the project area would likely reside or take temporary accommodations. The analysis area is 

approximately 6,672,640 acres in size (Gardner 2016).
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3.7.1. Population

The population of Sweetwater County in 2010 was 43,806 (U.S. Census Bureau 2010a). This is 

equivalent to a density of 4.2 persons per square mile of land area. Demographic data for 2010 indicates 

that 47.8% of the population was female and the median age of the total population was 32.8 years (U.S. 

Census Bureau 2010a). The county’s population was estimated to be 44,626 people in 2015, which is an 

increase of approximately 1.9% (U.S. Census Bureau 2016). 

The town of Superior, approximately 17 miles northwest of the project area, had a total population of 336 

in 2010 (U.S. Census Bureau 2010b). Superior’s population was estimated to be 323 in 2015, which is a 

decrease of 3.9% (U.S. Census Bureau 2016). The town of Rock Springs, approximately 31 miles 

southwest of the project area, had a total population of 23,036 in 2010 (U.S. Census Bureau 2010c). Rock 

Springs’ population was estimated to be 23,962 people in 2015, which is an increase of approximately 

4.0% (U.S. Census Bureau 2016).

3.7.2. Employment and Income

In 2014, mining, quarrying, and oil and gas extraction was the largest employment sector of the county 

(6,165 jobs), followed by local government (4,312 jobs), retail trade (2,842 jobs), accommodation and 

food services (2,420 jobs), construction (2,123 jobs), transportation and warehousing (1,742 jobs), 

manufacturing (1,497 jobs), health care and social assistance (1,479 jobs), and real estate, rental, and 

leasing (1,203 jobs) (Bureau of Economic Analysis 2015). According to preliminary data, Sweetwater 

County had a labor force of 21,549 in July 2016 (Wyoming Department of Workforce Services [WDWS] 

2016a). The preliminary unemployment rate for the same month and year in the county was 6.3% 

(WDWS 2016a). Unemployment rates rose in most counties across the state from July 2015 to July 2016, 

including Sweetwater County (WDWS 2016a).

The mean household income in Sweetwater County in 2014 was estimated to be $79,437 (U.S. Census 

Bureau 2014). In 2014, the average annual wage in the mining industry in Wyoming was $68,244 

(WDWS 2015). The average annual wage in Sweetwater County in 2014 was $45,808 (WDWS 2015).

There are two coal mines in Sweetwater County that provide employment: Black Butte and Leucite Hills 

(189 employees) and the Bridger Mining Complex (230 employees for surface operations and 236 

employees for underground operations) (Wyoming Mining Association 2016).

3.7.3. Housing

During the 2010 census, the 18,735 total housing units in Sweetwater County were 87.9% occupied (U.S. 

Census Bureau 2010a). The number of housing units was estimated to be 18,938 in 2014, which is an 

increase of 1.1% (U.S. Census Bureau 2016). The average household size in the 2010 census was 2.62, 

with 12.1% of the housing units vacant (U.S. Census Bureau 2010a). Of the vacant units, 934 were for 

rent and 337 were for sale.

In 2010, there were 10,070 housing units in the town of Rock Springs: 8,762 occupied units and 1,308

vacant units. Of the 1,308 vacant units, 667 were for rent and 199 were for sale (U.S. Census Bureau 

2010c). In Superior, there were 181 housing units in 2010; 131 occupied units and 50 vacant units. Of the 

vacant units, six were for rent and six were for sale (U.S. Census Bureau 2010b).
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3.7.4. Economy

The mining sector (particularly coal, oil, and natural gas) is a major economic engine of the Wyoming 

economy, both in direct employment and indirect industries such as transportation, food service, and 

accommodations. In the first quarter of 2015, mining accounted for 19% of the total payroll in Wyoming 

(WDWS 2016b). Coal is Wyoming’s second-largest source of tax revenue for state and local governments 

(Wyoming Mining Association 2016). 

Wyoming experienced a period of rapid economic growth from the third quarter of 2005 to the fourth 

quarter of 2008, with wage and employment levels increasing from prior year levels during every quarter. 

The state entered a downturn in the first quarter of 2009 that ended in the first quarter of 2010, followed 

by a period of moderate growth from the second quarter of 2010 to the first quarter of 2015. A recent 

downturn began in 2015, when Wyoming experienced a substantial decline in the price of oil, an extended 

period of low natural gas prices, and an erosion in the price of coal. As a result, the mining support 

industry experienced substantially reduced employment and wages (WDWS 2016b).

The average price for Wyoming coal in 2014 was $13.43 per ton, which is a decrease of 5.1% from 2012 

(Wyoming Mining Association 2016). Production at Sweetwater County coal mines in 2014 consisted of 

the following:

Black Butte and Leucite Hills: 4,017,845 tons 

Bridger Mine Complex (surface operation): 1,990,376 tons 

Bridger Mine Complex (underground operation): 3,369,731 tons 

Wyoming mineral production taxes are generally categorized as state severance taxes and ad valorem 

property taxes. Surface coal has a severance tax rate of 7.0% in Wyoming; underground coal has a 

severance tax rate of 3.75%. For Sweetwater County in 2014, the state assessed value for surface coal was 

$156,617,682 and the state assessed value for underground coal was $89,161,879 (an assessed value total 

of $245,779,561 for coal) (Wyoming Department of Revenue 2015). Total ad valorem production tax 

assessed for all mineral production in Sweetwater County was $136,274,730 (Wyoming Department of 

Revenue 2015). 

Coal production on federal lands is subject to royalty payments and disbursements under the MLA. The 

BLM receives revenues on coal leasing at three points: 1) a bonus paid at the time BLM issues the lease, 

2) an annual rental payment of $3.00 per acre or fraction thereof, and 3) royalties paid on the value of the 

coal after it has been mined. Production royalties have been established by law at 12.5% of the gross 

value of coal produced. Underground mining has a reduced royalty rate of 8%. Royalties are paid to the 

U.S. Treasury, and roughly half (49%) are returned to the states where production activity takes place. In 

Wyoming, money has been used to fund schools, highways, and community colleges. Table 3-10 shows 

the bonuses, rents, and revenues for coal in Wyoming in 2005, 2010, and 2015. 

Table 3-10. Reported Coal Revenues in Wyoming

Revenue Type

Revenue

Fiscal Year 2005 Fiscal Year 2010 Fiscal Year 2015

Bonuses $488,575,149 $96,758,009 $448,080,676

Rents $544,331 $521,005 $602,482

Royalties $349,912,519 $598,146,416 $539,904,453

Source: U.S. Department of the Interior, Office of Natural Resources Revenue (2005, 2010, 2015). 
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3.8. Soils 

The analysis area for impacts to soils consists of the project area. This area covers 560 acres and was 

chosen because it comprises the potential area of surface and subsurface impacts for the Proposed Action.

3.8.1. Soil Mapping Observations 

Soil complexes in the analysis area were identified through the Digital General Soil Map of the United 

States, or STATSGO. There is one soil complex in the analysis area consisting of seven soil series: 

Wint-Westvaco-Teagulf-Tasselman-Rogrube-Huguston-Haterton. Of the seven soil series, four have 

official soil series descriptions from the Natural Resources Conservation Service (NRCS) (NRCS 2016a).

These four soil series are described below. 

Teagulf series: Moderately deep, well-drained soils formed in modified residuum and slope wash

alluvium from calcareous sedimentary rocks. Found on erosional upland plains and alluvial fans. 

Slopes range from 0% to 8%. 

Rogrube series: Very deep, well-drained soils that formed in loess and residuum derived from 

gypsiferous shales. Found on plateaus. Slopes range from 1% to 12%. 

Huguston series: Well-drained soils that are shallow and very shallow to soft, calcareous 

sandstone. Formed in residuum and colluvial slope wash weathered from the underlying 

sedimentary beds. Found on upland hillslope positions and rock-controlled pediments. Slopes 

range from 0% to 30%. 

Haterton series: Well-drained soils that are shallow and very shallow to soft, calcareous shale. 

Formed in residuum and colluvial slope wash weathered from the underlying bedrock. Found on 

hill and ridge backslopes, shoulders, and summits. Slopes are 0% to 60%. 

Soil health is the continued capacity of soil to function as a vital living ecosystem that sustains plants, 

animals, and humans. Sensitive soils have soil properties that make them more susceptible to degradation 

with a disturbance. These properties include water erosion hazard, wind erosion hazard, soil drought 

susceptibility, excess salt, excess sodium, and rooting depth. 

Water erodibility indicates soil detachment by runoff and raindrop impact. Some of the most important 

soil properties that influence rainfall erosion are texture, organic matter content, structure size class, and 

the saturated hydraulic conductivity of the subsoil (NRCS 2016b). Wind erodibility indicates the 

susceptibility of soil to blowing or wind erosion. Soil properties that are most important with respect to 

soil blowing are soil texture class, organic matter content, carbonates in the fine-earth fraction, rock and 

pararock fragment content, and mineralogy. Soil moisture and the presence of frozen soil also influence 

soil blowing (NRCS 2016b). Droughty soils are determined through available water capacity 

measurements. Available water capacity is influenced by soil properties such as particle size; pore size, 

shape, and distribution; organic matter; type of clay mineral; and structure. Soils with excess salt may 

interfere with the absorption of water by plants and may also interfere with the exchange capacity of 

nutrient ions, resulting in nutritional deficiencies in plants. Soils with excess sodium may be characterized 

by an increased dispersion of organic matter and clay particles, reduced saturated hydraulic conductivity 

and aeration, and a general degradation of soil structure. Rooting depth is the depth to a restrictive layer 

such as bedrock; shallow soils often provide an unfavorable rooting environment and are prone to erosion 

(NRCS 2016b).

The inherent risk of soil degradation from disturbance for the single soil complex in the project area is 

shown in Table 3-11. 
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Table 3-11. Inherent Risk of Soil Degradation of the Project Area’s Wint-Westvaco Teagulf-TasselmanRogrube-Huguston-Haterton Soil Complex

Soil Property Level of Degradation Risk

Water erosion hazard Moderate

Wind erosion hazard Moderate

Drought susceptibility Moderate

Excess salt No data available

Excess sodium Low

Rooting depth Moderate

In summary, the Wint-Westvaco-Teagulf-Tasselman-Rogrube-Huguston-Haterton soil complex that 

covers the project area has four properties that moderately increase the risk of soil degradation and 

erosion—water erosion hazard, wind erosion hazard, droughtiness, and rooting depth. 

3.8.2. Baseline Soil Assessment

A baseline soil assessment (soil assessment) was conducted in 2012 on the project area as part of a larger 

survey of 1,266 acres (plus a 0.5-mile buffer) in the Bridger Mine Complex (BKS Environmental 

Associates, Inc. [BKS] 2012a). Soils in the 1,266-acre (plus a 0.5-mile buffer) study area are typical of 

sandy rangeland sites in southwestern Wyoming. Study area soils were classified taxonomically as Typic 

Torriorthents, Typic Torripsamments, Typic Haplocambids, Typic Torrifluvents, and Ustic Torriorthents 

(BKS 2012a). 

Due to prevailing climate conditions and vegetation, organic matter is accumulated slowly and is confined 

primarily to the surface horizons, resulting in a light coloration throughout the soil profile. While some 

soils in the study area derived in alluvium and residuum from sandstone and shale, others are of eolian 

origin. Soils are generally sandy loam, loamy sand, loam, or silty loam in texture (BKS 2012a). The soil 

assessment evaluated the soil’s suitability as a plant growth medium and found it to be limited by the 

physical factor of high sand texture and the chemical factors of pH, electrical conductivity (excess salt), 

sodium adsorption ratio (excess sodium), selenium, and calcium carbonate. Marginal material was found 

in six of the 17 sampled profiled and unsuitable material was found in three of the 17 sampled profiles. 

The recommended weighted average topsoil salvage depth over the entire study area was determined to 

be 0.90 feet. The soil assessment also noted that the wind and water erosion hazard across the study area 

varied from negligible to severe. Based on the generally sandy loam to loamy sand texture of the surface 

horizons throughout most of the study area, soils are somewhat more susceptible to erosion from wind 

than water (BKS 2012a). Soils vary in depth to paralithic material, from 10 to 12 inches (represented by 

shallow soil series such as Horsley and Huguston), to as deep as 36 to 60 inches (represented by soil 

series such as Thayer and Sagecreek) (BKS 2012a).

The soil assessment confirmed the presence of the Haterton, Huguston, Tasselman, and Wint soil series in or

near the project area, as described in Section 3.8.1. The Westvaco, Teagulf, and Rogrube series were not 

identified (BKS 2012a). Soil map units identified by the soil assessment in Section 12 are Boltus clay and 

clay loam; Boltus-Horsley Rock Outcrop complex; Corlett fine sand; Disturbed Land; Haterton sandy loam; 

Horsley-Boltus-Rock Outcrop complex; Horsley loam and sandy clay loam; Horsley-Rock Outcrop 

complex; Huguston sandy loam; Kandaly loamy sand and fine sand; Laney loam; Laney loam, saline phase; 

Leckman sandy loam; Slickspots Type; Terada-Huguston-Rock Outcrop complex; Terada sandy loam; 

Thayer sandy loam; Wint channery sandy loam; and Wint-Horsley-Rock Outcrop complex (BKS 2012a).
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Soil map units identified by the soil assessment in Section 24 are Boltus-Horsley Rock Outcrop complex; 

Dines-Laney loam association, Overflow phase; Haterton sandy loam; Horsley-Boltus Rock Outcrop 

complex; Horsley loam and sandy clay loam; Huguston sandy loam; Kandaly loamy sand and fine sand; 

Laney loam; Laney loam, saline phase; Leckman sandy loam; Rock Outcrop; Slickspots Type; TeradaHuguston-Rock Outcrop complex; Sagecreek loam; Terada sandy loam; Thayer sandy loam; Wint 

channery sandy loam; and Wint-Horlsey-Rock Outcrop complex (BKS 2012a). Approximate salvage 

depths of each map unit series range from 0 to 5 feet (BKS 2012a). Individual soil unit descriptions and 

soil laboratory analyses can be found in the soil assessment. Quantities (acreages) of soil map units in the 

project area were not provided in the soil assessment. No prime farmland is present in the project area 

(BKS 2012a). No alluvial valley floors are present in the project area; the subirrigated alluvial deposits 

are limited in area, have poor soil and water quality, and are of no value for agricultural development 

beyond grazing (BCC 2016).

3.9. Topography and Physiography

The impact analysis area for topography and physiography is the 560-acre mining plan modification area. 

This area was chosen because the potential effects to topography and physiography would not extend 

beyond the footprint of proposed surface disturbance. The terrain at the Bridger Mine Complex varies 

from a series of gently sloping, flat-topped bluffs and moderate to steep-sided ridges to broad, gently 

sloped valleys. The latter terrain occurs over a length of 2 to 3 miles at each end of the permit area, which 

covers the mining plan modification area. Bluffs and ridges are capped by erosion-resistant, moderately to 

strongly indurated sandstone. The slopes between successive bluffs consist of less resistant shale and 

weakly indurated sandstone and siltstone. Elevations range from approximately 6,800 to 7,100 feet.

3.10. Vegetation

The impact analysis area for vegetation resources is the project area. This area was chosen because the 

potential impacts to vegetation would be limited to the footprint of the proposed surface mining activities.

This area covers 560 acres and was chosen because it comprises the potential area of surface and 

subsurface impacts for the Proposed Action.

3.10.1. Land Cover Mapping Observations

Vegetation communities in the project area were identified and described using data from the USGS 

National Gap Analysis Program (GAP). Land cover types or ecological systems are defined as 

recurring groups of biological communities found in similar physical environments and influenced 

by similar ecological process (USGS 2011). Ecological systems descriptions and acres are derived 

from the GAP descriptions (NatureServe 2015) and GAP geographic information system (GIS) data

(USGS 2011), respectively. Seven ecological systems were identified in the impact analysis area. 

Table 3-12 lists the ecological systems in the vegetation impact analysis area.

Table 3-12. Ecological Systems in the Vegetation Analysis Area

Ecological System Acres in Analysis Area

Inter-Mountain Basins Active and Stabilized Dune 11.0

Inter-Mountain Basins Big Sagebrush Shrubland 374.0

Inter-Mountain Basins Greasewood Flat 0.3

Inter-Mountain Basins Mat Saltbush Shrubland 1.8
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Ecological System Acres in Analysis Area

Inter-Mountain Basins Mixed Salt Desert Scrub 128.3

Inter-Mountain Basins Shale Badland 0.3

Western Great Plains Riparian Woodland and Shrubland 43.7

Total 559.4

3.10.1.1. INTER-MOUNTAIN BASINS ACTIVE AND STABILIZED 

DUNE

The Inter-Mountain Basins Active and Stabilized Dune ecological system covers approximately 2% of the 

analysis area. This ecological system occurs on plains, valleys, and basins in the Intermountain western 

United States. It is often composed of a mosaic of migrating dunes, anchored dunes, stabilized dunes, and 

bare dunes with sparse to moderately dense vegetation. Vegetation may be composed of Indian ricegrass 

(Achnatherum hymenoides), needle and thread grass (Hesperostipa comata), yellow wildrye (Leymus 

flavescens), alkali sacaton (Sporobolus airoides), sandhill muhly (Muhlenbergia pungens), blowout grass 

(Redfieldia flexuosa), lemon scurfpea (Psoralidium lanceolatum), joint-fir species (Ephedra spp.), sand 

sagebrush (Artemisia filifolia), big sagebrush (Artemisia tridentata var. tridentata), fourwing saltbush 

(Atriplex canescens), yellow rabbitbrush (Chrysothamnus viscidiflorus), blackbrush (Coleogyne 

ramosissima), rubber rabbitbrush (Ericameria nauseosa), antelope bitterbrush (Purshia tridentata),

greasewood (Sarcobatus vermiculatus), and fourpart horsebrush (Tetradymia tetrameres).

3.10.1.2. INTER-MOUNTAIN BASINS BIG SAGEBRUSH SHRUBLAND

The Inter-Mountain Basins Big Sagebrush Shrubland ecological system covers approximately 66.9% of 

the analysis area. This ecological system typically occurs in broad basins between foothills, plains, and 

mountain ranges between 2,600 and 8,200 feet in elevation. This ecological system is dominated by 

Wyoming big sagebrush (Artemisia tridentata var. wyomingensis) and/or big sagebrush (Artemisia 

tridentata var. tridentata). Disturbed stands may be co-dominated by yellow rabbitbrush (Chrysothamnus 

viscidiflorus), rubber rabbitbrush (Ericameria nauseosa), antelope bitterbrush (Purshia tridentata), or 

mountain snowberry (Symphoricarpos oreophilus). Common grass species may include Indian ricegrass

(Achnatherum hymenoides), needle and thread grass (Hesperostipa comata), blue grama (Bouteloua 

gracilis), thickspike wheatgrass (Elymus lanceolatus), basin wildrye (Leymus cinereus), James’ galleta 

(Pleuraphis jamesii), western wheatgrass (Pascopyrum smithii), or Sandberg bluegrass (Poa secunda).

3.10.1.3. INTER-MOUNTAIN BASINS GREASEWOOD FLAT

The Inter-Mountain Basins Greasewood Flat ecological system covers approximately 0.05% of the 

analysis area. This ecological system typically occurs near drainages on stream terraces. Soils are typically 

saline and sites usually have a shallow water table and flood intermittently. This ecological system 

typically occurs as a mosaic of multiple communities with open to moderately dense shrublands dominated 

or co-dominated by greasewood (Sarcobatus vermiculatus). Common shrubs present include fourwing 

saltbush (Atriplex canescens), shadscale saltbush (A. confertifolia), Gardner’s saltbush (A. gardneri), 

Wyoming big sagebrush (Artemisia tridentata var. wyomingensis), big sagebrush (Artemisia tridentata var. 

tridentata), silver sagebrush (Artemisia cana var. cana), or winterfat (Krascheninnikovia lanata).
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3.10.1.4. INTER-MOUNTAIN BASIN MAT SALTBUSH SHRUBLAND

The Inter-Mountain Basins Mat Saltbush Shrubland ecological system covers approximately 0.3% of the 

analysis area. This ecological system on rolling plains, wind-swept basins, and gentle slopes, and supports 

dwarf shrublands. These shrublands are dominated by saltbush species, typically Gardner’s saltbush 

(Atriplex gardneri) and/or mat saltbush (Atriplex corrugata). Other dominant or co-dominant dwarf 

shrubs may include longleaf wormwood (Artemisia longifolia), birdfoot sagebrush (Artemisia pedatifida), 

or bud sagebrush (Picrothamnus desertorum). The herbaceous layer is typically sparse and consists of 

perennial forbs and perennial grasses.

3.10.1.5. INTER-MOUNTAIN BASINS MIXED SALT DESERT SCRUB

The Inter-Mountain Basins Mixed Salt Desert Scrub ecological system covers approximately 22.9% of 

the analysis area. This ecological system includes open-canopied shrublands found in saline basins, 

plains, and alluvial slopes. Vegetation is typically open to moderately dense and composed of one or more 

saltbush species, such as fourwing saltbush (Atriplex canescens), shadscale saltbush (A. confertifolia), 

cattle saltbush (A. polycarpa), or spinescale saltbush (A. spinifera). Other dominant or co-dominant 

shrubs include Wyoming big sagebrush (Artemisia tridentata var. wyomingensis), yellow rabbitbrush 

(Chrysothamnus viscidiflorus), rubber rabbitbrush (Ericameria nauseosa), winterfat (Krascheninnikovia 

lanata), bud sagebrush (Picrothamnus desertorum), Nevada jointfir (Ephedra nevadensis), spiny hopsage 

(Grayia spinosa), or horsebrush species (Tetradymia spp.). The herbaceous layer varies from sparse to 

moderately dense and is dominated by perennial grass species.

3.10.1.6. INTER-MOUNTAIN BASINS SHALE BADLAND

The Inter-Mountain Basins Shale Badland ecological system covers approximately 0.05% of the analysis 

area. This ecological system is composed of barren and sparsely vegetated substrates typically derived 

from shales, marine shales, mudstones, and siltstones. Vegetation is sparse and is dominated by dwarf 

shrubs and herbaceous vegetation. 

3.10.1.7. WESTERN GREAT PLAINS RIPARIAN WOODLAND AND 

SHRUBLAND

The Western Great Plains Riparian Woodland and Shrubland ecological system covers approximately 

7.8% of the analysis area. This ecological system is found in the riparian areas of small and medium-sized 

rivers and streams on alluvial soils in highly variable landscape settings throughout the western Great 

Plains. Vegetation communities in this ecological system are dominated by willow species (Salix spp.), 

eastern cottonwood (Populus deltoides), silver sagebrush (Artemisia cana var. cana), western wheatgrass 

(Pascopyrum smithii), and sand dropseed (Sporobolus cryptandrus). This ecological system can be 

heavily degraded through livestock grazing and agriculture. Invasive species such as saltcedar (Tamarix 

spp.) and weedy grasses and forbs typically occur if this system becomes degraded.

3.10.2. Baseline Vegetation Assessment

A baseline vegetation assessment (vegetation assessment) was conducted in 2012 on the project area as 

part of a larger survey of 1,266 acres in the Bridger Mine Complex (BKS 2012b). The baseline vegetation 

inventories were used to delineate range sites and vegetation resources within the mining plan 

modification area.
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Vegetation mapping was conducted within both the mining plan modification area and a 0.5-mile buffer,

whereas vegetation sampling for vegetative cover and shrub density was only conducted within the 

mining plan modification area and not within the 0.5-mile buffer. Range site mapping performed in 2012 

included areas that had not previously been mapped and modified range sites that had changed since the 

original mapping in 1979. Mapping was performed using an aerial photograph with the original mapping 

as the base map. Range sites were mapped using soil texture, soil depth, and dominant vegetation. The 

range sites outlined on the base maps were verified in the field during field sampling. Sampling 

procedures were designed according to the WDEQ Land Quality Division S-1 Rules Package. Vegetation 

cover data were collected using point intercept transects and the Daubenmire quadrate method, and 

percent absolute cover and total vegetation cover were calculated. Surveys were conducted for threatened 

and endangered plant species as well as for BLM Rock Springs Field Office Sensitive Plant Species. 

Noxious weeds and Sweetwater County–declared weeds were noted if observed within the mining plan 

modification area (BKS 2012b).

Quantitative analyses were performed for six range sites located within the mining plan modification area: 

Saline Upland, Saline Lowland, Sands, Shallow Loamy, Loamy, and Saline Sub-irrigated. Shallow 

Loamy and Loamy were sampled together but mapped separately. Range sites identified by the vegetation 

assessment in Section 12 are Sands, Shallow Loamy, Saline Upland, Saline Lowland, and Saline Subirrigated (BKS 2012b). Range sites identified by the vegetation assessment in Section 24 are Shallow 

Loamy, Saline Upland, Saline Lowland, and Loamy (BKS 2012b). Quantitative analyses of vegetation 

cover and species inventory data specifically for the project area were not provided in the vegetation 

assessment. Tables 3-13 through 3-15 summarize the results of the vegetation assessment analyses.

Table 3-13. Mining Plan Modification Area Absolute Vegetation by Lifeform for Each Range Site

Annual 

Grasses

Cool Season 

Perennial Grasses*

Annual 

Forbs

Perennial 

Forbs Sub-Shrubs Shrubs

Saline Upland 0 13.1 0 0.5 5.3 10.2

Shallow Loamy-Loamy 1.0 7.9 0.5 4.2 0.85 11.8

Saline Lowland 0 12.4 0 0.1 1.0 15.6

Sands 0.05 8.3 0.15 0.9 2.6 15.1

Saline Sub-irrigated 0 63* 0.3 2.7 0 0

Source: BKS (2012b).

* In the Saline Sub-irrigated range site there was only 3% Cool Season Perennial Grass cover and the remainder was grass-like species.

Table 3-14. Mining Plan Modification Area Relative Cover by Lifeform

Annual 

Grasses

Cool Season 

Perennial Grasses

Annual 

Forbs

Perennial 

Forbs Sub-Shrubs Shrubs

Saline Upland 0% 45.0% 0% 1.7% 18.2% 35.05%

Shallow Loamy-Loamy 3.8% 30.1% 1.9% 16.0% 3.2% 44.95%

Saline Lowland 0% 42.6% 0% 0.3% 3.4% 53.6%

Sands 0.18% 30.6% 0.55% 3.3% 9.6% 55.7%

Saline Sub-irrigated 0% 95.45% 0.5% 4.05% 0% 0%

Source: BKS (2012b).

* In the Saline Sub-irrigated range site there was only 3% Cool Season Perennial Grass cover and the remainder was grass-like species.
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Table 3-15. Mining Plan Modification Area Shrub Density by Range Site

Shrub

(number per m2

)

Shrub

(number per acre)

Sub-shrub 

(number per m2

)

Sub-shrub 

(number per acre)

Total Density

(number per m2

)

Total Density

(number per acre)

Saline Upland 0.6 2,274.4 3.3 13,452.2 3.9 15,726.6

Shallow Loamy-Loamy 1.6 6,523.8 0.7 2,751.9 2.3 9,275.7

Saline Lowland 1.9 7,794.5 0.6 2,622.5 2.6 10,417.0

Sands 1.4 5,722.5 0.4 1,756.4 1.8 7,478.9

Source: BKS (2012b)

Note: No shrubs were surveyed in the Saline Sub-irrigated community

Plant species diversity varied among range sites. The Sands range site had the greatest species diversity at 

40 species for the combined qualitative and quantitative data and a species richness of 5.1 species per 

plot. Saline Sub-irrigated had the lowest species diversity at eight species. Saline Upland, Shallow 

Loamy-Loamy, and Saline Lowland had similar species richness calculations to Sands, ranging between 

4.2 and 4.3 (BKS 2012b).

Habitat and species surveys were conducted for two federally listed plant species with potential to occur 

within the mining plan modification area: Ute ladies’-tresses (Spiranthes diluvialis) and blowout 

penstemon (Penstemon haydenii). No plants or suitable habitats were observed in the mining plan 

modification area for either species. Suitable habitats for BLM Rock Springs Field Office Sensitive Plant 

Species were not identified during field surveys (BKS 2012b).

3.10.3. Invasive Species and Noxious Weeds

A weed is any undesirable plant species, but weed species may be classified as non-native or introduced, 

or they may be formally designated by federal, state, or other entities as invasive or noxious. Federal and 

state agencies maintain lists of noxious weed species that must be controlled, as required by federal and 

state laws and regulations. Generally, federal weed laws and regulations target unwanted plant 

introductions, whereas state laws and regulations are aimed at the control and removal of noxious weeds.

The Wyoming Weed and Pest Council (WWPC) defines noxious weeds as “the weeds, seeds or other 

plant parts that are considered detrimental, destructive, injurious or poisonous, either by virtue of their 

direct effect or as carriers of diseases or parasites that exist within this state” (WWPC 2013). If a plant is 

listed as a Wyoming designated noxious weed, that listing provides statewide legal authority to regulate 

and manage it. Wyoming Statute 11-5-102 (a)(xi) designated noxious weeds are listed in Table 3-16.

Table 3-16. Wyoming Designated Noxious Weeds

Scientific Name Common Name

Agropyron repens Quackgrass 

Arctium minus Common burdock

Cardaria draba, C. pubescens Hoary cress 

Carduus acanthoides Plumeless thistle

Carduus nutans Musk thistle 

Centaurea diffusa Diffuse knapweed
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Scientific Name Common Name

Centaurea maculosa Spotted knapweed

Centaurea repens Russian knapweed

Chrysanthemum leucanthemum Ox-eye daisy 

Cirsium arvense Canada thistle 

Convolvulus arvensis Field bindweed 

Cynoglossum officinale Houndstongue

Elaeagnus angustifolia Russian olive

Euphorbia esula Leafy spurge 

Franseria discolor Skeletonleaf bursage 

Hyoscyamus niger Black henbane

Hypericum perforatum Common St. Johnswort

Isatis tinctoria Dyers woad

Lepidium latifolium Perennial pepperweed 

Linaria dalmatica Dalmatian toadflax

Linaria vulgaris Yellow toadflax

Lythrum salicaria Purple loosestrife

Onopordum acanthium Scotch thistle

Sonchus arvensis Perennial sowthistle 

Tamarix species Saltcedar

Tanacetum vulgare Common tansy

Source: WWPC (2016).

In addition to noxious weed status, Wyoming Statute 11-5-102(a)(viii) recognizes county-level declared 

weeds, defined as “any plant which the board and the Wyoming weed and pest council have found, either 

by virtue of its direct effect, or as a carrier of disease or parasites, to be detrimental to the general welfare 

of persons residing within a district” (WWPC 2016). The current list of declared weed species for 

Sweetwater County, Wyoming, is provided as Table 3-17.

Table 3-17. Sweetwater County Declared Weed Species

Scientific Name Common Name

Galium verum Lady’s bedstraw

Glycyrrhiza lepidota Wild licorice

Hordeum jubatum Foxtail barley

Phragmites australis Common reed

Thermopsis montana Mountain thermopsis

Source: WWPC (2016)
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BKS conducted a baseline vegetation assessment of a 1,266-acre study area in 2012. No noxious weed 

species designated by the State of Wyoming were noted during the surveys; however, one Sweetwater 

County declared weed, foxtail barley (Hordeum jubatum), was observed in the mining plan modification 

area. The vegetation baseline assessment states that the foxtail barley had a low occurrence frequency 

with a limited contribution to vegetative cover (BKS 2012b).

3.11. Water Resources

3.11.1. Surface Water Resources

The impact analysis area for surface water resources (Figure 3-7) is the boundary of the Lower Deadman 

Wash Hydrologic Unit Code (HUC) 12 watershed (33,990 acres). This area was chosen because it 

provides a logical topographical boundary for the surface water resources that could be potentially 

affected by the proposed mining activities in the mining plan modification area. The Deadman Wash 

watershed drains a majority of the Bridger Mine Complex. Deadman Wash is the major tributary to Bitter 

Creek, which is a major tributary of the Green River. All of the watersheds and associated channels 

traversing the mine permit area are ephemeral and typically exhibit flow only as a result of rainfall or 

snowmelt. 

Unnamed ephemeral tributaries to Black Rock Creek and the Continental Divide Basin Drainage in the 

Great Divide Basin occur in the northern portion of the Bridger Mine Complex permit area, as well as a 

portion of the mining plan modification area. There are approximately 1 acre of intermittent lake/pond, 

0.5 acre of perennial lake/pond, and 0.4 acre of reservoir in the surface water impact analysis area.

3.11.1.1. SURFACE WATER QUANTITY

All native stream channels within both the surface and underground mine areas of the Bridger Mine 

Complex permit area are ephemeral in nature and flow only in response to precipitation or snowmelt. 

Major native channels include Deadman Wash and its tributaries, which are Tenmile Draw, Nine-Mile 

Draw, and Nine and One-Half Mile Draw. Collectively, these channels provide drainage for over 83 

square miles of lands surrounding the Bridger Mine Complex on the west side of the Continental Divide. 

Flow data from water monitoring stations show that runoff varies dramatically from year to year and is 

highly dependent on the occurrence of summer storm events. Without summer rainfall, there are long 

periods of no flow recorded at each station, sometimes over the course of the entire monitoring season 

(typically May through September). The disturbed Ninemile Wash watershed has the most frequent flows, 

with flow occurring roughly 3% of the time. The Deadman Wash Tributary, the smallest watershed 

monitored, has the most infrequent flows, as flow occurs less than 1% of the time. On the mainstem of 

Deadman Wash, flow is more frequent across a range of flow values at the downstream station, compared 

to the station that drains an undisturbed area above the mining pits.

On Tenmile Draw, flow has occurred 2.5% of the time at the water monitoring station downstream of 

mining disturbance and 1.4% of the time at the water monitoring station at the upstream permit boundary. 

However, flow at the upstream permit boundary was more frequent across a range of flows.

Surface water rights in the Deadman Wash watershed are entirely held by the Jim Bridger Power Plant, 

the Leucite Hills Mine, and the Bridger Mine Complex. Surface water rights are mostly held for industrial 

purposes such as sediment control, flood control, and facilities.
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Figure 3-7. Surface water and groundwater impact analysis areas.
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3.11.1.2. SURFACE WATER QUALITY

Prior to the Bridger Mine Complex’s original mine permit, collected surface water quality data showed 

that total suspended solids (TSS) was the only water quality monitoring parameter (WDEQ-LQD 2014). 

The TSS was consistently high, and was, therefore, of concern to instream water quality. In addition to 

analyzing for TSS in every sampled flow event at the monitoring stations, BCC also analyzes collected 

surface-water chemical quality biannually at monitoring stations for the following parameters: pH, 

electrical conductivity, total dissolved solids (TDS), boron, fluoride, ammonia-nitrogen, sodium 

adsorption ratio, total alkalinity, total hardness, silica, turbidity, bicarbonate, carbonate, hydroxide, 

chloride, nitrate and nitrite, sulfate, calcium, magnesium, potassium, sodium, aluminum, arsenic, barium, 

cadmium, chromium, copper, iron, lead, manganese, mercury, molybdenum, nickel, selenium, zinc, and 

cation-anion balance (WDEQ-LQD 2014).

The Wyoming Department of Environmental Quality Water Quality Division (WDEQ-WQD) has two 

different surface water classifications for Deadman Wash. Upstream of the Jim Bridger Power Plant, 

Deadman Wash is classified as Class 3B water. Class 3B waters are intermittent or ephemeral streams 

with sufficient hydrology to normally support and sustain communities of aquatic life, including 

invertebrates, amphibians, or other flora and fauna which inhabit water of the state at some stage of their 

life cycles. Supported uses include aquatic life other than fish, recreation, wildlife, industry, agriculture, 

and scenic value. Class 3B waters need to meet acute and chronic water quality standards for aquatic life 

other than fish. The WDEQ-WQD numeric standards for selected constituents for Class 3B surface waters 

are in Table 3-18.

Downstream of the Jim Bridger Power Plant, Deadman Wash is classified as Class 2AB(ww) water. The 

change in classification is presumably due to the flow contributed from the surge pond at the power plant 

that the WDEQ-WQD deems sufficient to support drinking water and fish. Class 2AB waters support 

game-fish populations or spawning and nursery areas at least seasonally. Class 2AB waters are also 

presumed to have sufficient water quality and quantity to support drinking water supplies. Supported uses 

include drinking water, game fish, nongame fish, fish consumption, other aquatic life, recreation, wildlife, 

agriculture, industry, and scenic value. The “ww” notation indicates a predominance of warm-water 

species present. The WDEQ-WQD numeric standards for selected constituents for Class 2AB surface 

waters are in Table 3-18.

The WDEQ-WQD has classified Ninemile Wash, Nine and One-Half Mile Wash, and Tenmile Draw as 

Class 3B water. All other unnamed ephemeral tributaries to Deadman Wash would also be classified as 

Class 3B under the unlisted waters guidance of Chapter 1 of the WDEQ-WQD Rules and Regulations 

(WDEQ-WQD 2013).
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Table 3-18. Wyoming Department of Environmental Quality Water Quality Division Numeric Standards for 

Class 2AB(ww), Class 2C, and Class 3B Surface Waters

Constituent Units

Class 2AB(ww) Class 2C Class 3B Class 3B Class 3B

Deadman Wash 

Below Jim Bridger 

Power Plant

Bitter 

Creek

Deadman Wash 

Above Jim Bridger 

Power Plant

Tenmile 

Draw

Ninemile Wash and 

Other Class 3B Streams 

in Impact Analysis Area

Aluminum 

(dissolved)

mg/L 0.75 0.75 0.75 0.75 0.75

Ammonia (NH3

as N) (total)

mg/L 0.92 0.95 N/A N/A N/A

Arsenic mg/L 0.01 0.01 0.15 0.15 0.15

Barium (total) mg/L 2 N/A N/A N/A N/A

Cadmium 

(dissolved)

mg/L 0.0006 0.0004 0.0004 0.0003 0.0006

Chloride (total) mg/L 230 230 N/A N/A N/A

Chromium (III) mg/L 0.1 0.136 0.136 0.087 0.231

Copper 

(dissolved)

mg/L 0.029 0.017 0.017 0.011 0.029

Dissolved 

oxygen

mg/L >3 >3 N/A N/A N/A

Iron (dissolved) mg/L 0.3 1 1 1 1

Lead (dissolved) mg/L 0.011 0.005 0.005 0.002 0.011

Manganese 

(dissolved)

mg/L 0.050 2.188 2.188 1.621 3.105

Mercury μg/L 0.05 0.051 0.77 0.77 0.77

Nickel mg/L 0.169 0.098 0.098 0.061 0.169

Nitrate + Nitrite 

as N (total)

mg/L 10 N/A N/A N/A N/A

pH SU 6.5–9.0 6.5–9.0 6.5–9.0 6.5–9.0 6.5–9.0

Selenium 

(dissolved)

mg/L 0.0046 0.0046 0.0046 0.0046 0.0046

Temperature °C <30 <30 N/A N/A N/A

Turbidity NTU <15 <15 N/A N/A N/A

Zinc (dissolved) mg/L 0.388 0.225 0.225 0.141 0.388

Note: μg/L = micrograms per liter; mg/L = milligrams per liter; NTU = nephelometric turbidity unit; SU = standard unit; °C = degrees Celsius; N/A = not 

applicable. 

Between 1996 and 2011, on Tenmile Draw, approximately 22 samples were collected upstream of mining 

and approximately 18 samples were collected downstream of mining (WDEQ-LQD 2014). Sodium 

chloride was the dominant water type at both upstream and downstream monitoring stations, occurring in 

41% and 61% of the samples, respectively. TDS ranged from 118 to 5,040 milligrams per liter (mg/L) at 

the upstream station between 1996 and 2011, with a median of 1,450 mg/L. TDS was lower at the 

downstream station, ranging from 168 to 2,260 mg/L, with a median of 960 mg/L. TSS concentrations in 

the Deadman Wash drainage were highly variable, ranging from <5 to 121,000 mg/L at the upstream 

station, with a median of 2,900 mg/L. TSS concentrations at the downstream station ranged from 20 to 

308,000 mg/L, with a median of 12,600 mg/L. Only one pH sample was reported at either station, and the 

value (9.09) at the upstream station slightly exceeded WDEQ-WQD Class 3B standards.
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Dissolved metal concentrations at both stations on Tenmile Draw were mostly low over the 1997–2011 

period, with numerous values below detection limits (WDEQ-LQD 2014). The maximum concentrations 

of aluminum (4.7 mg/L), copper (0.2 mg/L), iron (2.63 mg/L), and selenium (0.007 mg/L) at the upstream 

station exceeded WDEQ-WQD Class 3B water quality standards. Between 1996 and 2011, the maximum 

concentrations of aluminum (3.5 mg/L), copper (0.04 mg/L), iron (1.38 mg/L), and selenium (0.025 

mg/L) at the downstream station also exceeded Class 3B standards. Between 2001 and 2012, periodic 

selenium exceedances were seen at both the upstream and downstream stations. Because exceedances 

occasionally occur at the upstream station, natural sources of selenium appear to exist in the Tenmile 

Draw watershed.

Between 1996 and 2012, approximately 30 samples were collected on Ninemile Wash. Magnesium 

chloride was the dominant water type, occurring in 38% of the samples (WDEQ-LQD 2014). TDS ranged 

from 118 to 5,040 mg/L between 1996 and 2012, with a median of 1,450 mg/L. TSS concentrations were 

highly variable between 1996 and 2012. The TSS from 472 samples ranged from 34 to 112,000 mg/L, 

with a median of 7,200 mg/L. The maximum concentrations of aluminum (11.9 mg/L), cadmium (0.002 

mg/L), copper (0.06 mg/L), iron (7.33 mg/L), lead (0.04 mg/L), and selenium (0.072 mg/L) exceeded 

WDEQ-WQD Class 3B standards. These constituents have also shown periodic exceedances at other 

stations in the Deadman Wash drainage. However, the dissolved metal data indicate that Ninemile Wash 

may have the poorest water quality among the Deadman Wash tributaries near the Bridger Mine 

Complex, as metal concentrations are often the highest.

Between 1996 and 2012, approximately 22 samples were collected upstream of mining on Deadman 

Wash, and approximately 24 samples were collected downstream of mining (WDEQ-LQD 2014). 

Calcium bicarbonate was the dominant water type at the upstream station, occurring in 63% of the 

samples. The water type was more variable at the downstream station. Magnesium chloride occurred in 

24% of the samples, while calcium bicarbonate and calcium sulfate each occurred in 21% of the samples. 

TDS ranged from 60 to 868 mg/L at the upstream station from 1996 to 2012, with a median of 295 mg/L. 

The TDS at the downstream station was much higher during this period, ranging from 118 to 4,730 mg/L, 

with a median of 1,470 mg/L. TSS concentrations at the upstream station ranged from 50 to 25,600 mg/L 

(from 80 samples), with a median of 5,410 mg/L. TSS concentrations at the downstream station ranged 

from 40 to 125,000 mg/L (from 418 samples), with a median of 10,600 mg/L.

Dissolved metal concentrations at both the upstream and downstream stations on Deadman Wash were 

mostly low between 1996 and 2012, with numerous values below detection limits (WDEQ-LQD 2014). 

The maximum concentrations of aluminum (6.0 mg/L), copper (0.02 mg/L), iron (2.96 mg/L), and 

selenium (0.006 mg/L) at the upstream station exceeded Class 3B water quality standards. The maximum 

concentrations of aluminum (30.7 mg/L), iron (9.44 mg/L), and selenium (0.075 mg/L) at the downstream 

station also exceeded Class 3B standards. 

3.11.2. Groundwater Resources

The impact analysis area for groundwater resources is the boundary of assessment that the CHIA used for 

mine permitting (673,297 acres) (see Figure 3-7) (WDEQ-LQD 2014). This area was chosen because it 

covers the groundwater resources that could be potentially affected by the proposed mining activities in 

the mining plan modification area.

The western extent of the Ericson Sandstone outcrop represents the western extent of the groundwater 

impact analysis area. The horizontal extent of the groundwater impact analysis area encompasses 

approximately 1,040 square miles, extending as far as 16 miles north, 10 miles east, and 13 miles west of 

the Bridger Mine Complex; and 2 miles south, 2 miles west, and 3 miles east of the Black Butte Mine. 

The vertical extent of the groundwater impact analysis area includes six aquifer units of concern that are 
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within the horizontal extent of the groundwater impact analysis area: alluvial, Fort Union Formation, 

Lance Formation, Almond Formation, Ericson Sandstone, and backfill. A brief discussion of each of 

these units is presented below.

When in hydrologic connection, materials classified as alluvium and colluvium are categorized together 

as alluvial deposits. The alluvium along Bitter Creek, Deadman Wash, and segments of their tributaries 

store and transmit water in sufficient quantities to be considered aquifers in some parts of the groundwater 

impact analysis area. Alluvial aquifers are generally discontinuous and are present only along major 

drainages.

The coal mine pits are in the Fort Union, Lance, and Almond Formations. Within the Fort Union 

Formation lie economic coal deposits and vertebrate fossils of scientific significance (BLM 2003). The 

Deadman Coal Zone of the Fort Union Formation is about 10 to 30 feet thick. All of the mining at the 

Bridger Mine Complex occurs in the Fort Union Formation. Seven of the 11 pits at the Black Butte Mine 

are in the Fort Union Formation. The Black Butte Mine has two pits in reclamation that mined coal from 

the Lance Formation. All four pits at the Leucite Hills Mine mined coal from the Almond Formation. 

Two out of 11 mine pits at the Black Butte Mine are in the Almond Formation.

The Ericson Sandstone outcrops to the eastern edge of the Leucite Hills Mine and the Bridger Mine 

Complex. It consists of massive beds of sandstone and conglomerate with a thickness of up to 700 feet. 

Because of yield and water quality as compared to other aquifers in the area, the Ericson Sandstone is 

generally used as a water supply for municipal and industrial use. The Ericson Sandstone is tapped as a 

potable water source for the town of Superior, Wyoming. Coal mine facility wells are also completed in 

the Ericson Sandstone.

The outcrops of Wasatch Formation and Fox Hills Sandstone and Lewis shale are also in the vicinity of 

the coal mines. The Wasatch Formation outcrops to the west of the mine permit boundaries. The Wasatch 

Formation is discontinuous and of limited extent within the mine permit boundaries. Some of the Bridger 

Mine Complex’s Fort Union Formation wells are completed in both the Fort Union Formation and the 

Wasatch Formation. Fox Hills Sandstone and Lewis shale has very low hydraulic conductivity and 

therefore the hydrologic impacts caused by mining are expected to be mostly limited to very short 

distances within the formation.

The backfill aquifer is a new aquifer created by saturation of overburden materials placed into the mined 

pit after the coal is removed. The backfilled materials consist primarily of overburden materials removed 

to expose the coal seam for mining. The water quality of the backfill aquifer is intended to support 

livestock use, which is the approved post-mining land use for the area.

The groundwater in the vicinity of the Bridger Mine Complex is contained in several aquifers. Alluvial 

aquifers are found in some of the drainage channels and overburden, coal and interburden, and 

underburden aquifers are found in the Fort Union and Lance Formations. Transmitting properties of each 

of these formations vary with typical sustained yields of only a few gpm, but each of these aquifers can 

yield several tens of gpm in a few locations.

3.11.2.1. GROUNDWATER QUANTITY

Water levels from 27 monitor wells were used to characterize the groundwater levels in the alluvial 

aquifer during 2010–2012 (WDEQ-LQD 2014). The specific locations of the monitor wells, and the 

aquifers they are associated with, are shown on Figures 14 through 19 in the CHIA (WDEQ-LQD 2014). 

The highest median 2010–2012 water-level elevation of 6,814 feet was observed at the Randor Springs 

well on Black Rock Creek. The lowest median 2010–2012 water-level elevation of 6,539 feet was 

observed at Black Butte Mine well 567794 on Bitter Creek.
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Water levels from 26 monitor wells were used to characterize the groundwater levels in the overburden 

aquifer during 2010–2012 (WDEQ-LQD 2014). The highest median 2010–2012 overburden water-level 

elevation of 6,997 feet was observed at Black Butte Mine well SW3-OB in the Almond Formation. The 

lowest median 2010–2012 water-level elevation of 6,625 feet was observed at the Bridger Mine Complex 

well 81-03-OB in the Fort Union Formation.

Water levels from 21 monitor wells were used to characterize the groundwater levels in the coal seams of 

the Fort Union Formation, Almond Formation, and Lance Formation during 2010–2012 (WDEQ-LQD

2014). The highest median 2010–2012 coal water-level elevation of 6,971 feet was observed at Black 

Butte Mine well SW1-CZ in the Almond Formation. The lowest median 2010–2012 water-level elevation 

of 6,537 feet was observed at well 534990 at the Black Butte Mine.

Water levels from 21 monitor wells were used to characterize the groundwater levels in the underburden 

aquifer during 2010–2012 (WDEQ-LQD 2014). The highest median 2010–2012 underburden water-level 

elevation of 7,008 feet was observed at Black Butte Mine Almond Formation well SW3-UB. The lowest 

median 2010–2012 water-level elevation of 6,635 feet was observed at Lance Formation well 81-03-LA 

to the west of the Bridger Mine Complex mining plan modification area.

Three wells had groundwater level data available in the WDEQ-WQD Hydrology Database for the 

Ericson Sandstone aquifer (WDEQ-LQD 2014). All three wells were located in the Leucite Hills Mine 

area. The highest median 2010–2012 Ericson Sandstone aquifer water-level elevation of approximately 

6,657 feet was observed at the Leucite Hills Mine well LE05. The lowest median 2010–2012 water-level 

elevation of approximately 6,612 feet was observed at the Leucite Hills Mine well LE10.

Water levels from 16 monitor wells were used to characterize the groundwater levels in the backfill 

aquifer during 2010–2012 (WDEQ-LQD 2014). The highest median 2010–2012 backfill water-level 

elevation of 6,889 feet was observed at the Bridger Complex Mine well 82-01-SP. The lowest median 

2010–2012 water-level elevation of 6,556 feet was observed at Black Butte Mine well 568298.

3.11.2.2. GROUNDWATER QUALITY

Groundwater quality is more heterogeneous than groundwater quantity and varies both between and 

within the aquifers. There are fewer wells with water-quality data compared to the number of wells with 

water-level data, and the spatial distribution of the well monitor network is too sparse to conduct a robust 

analysis of the impacts of mining on groundwater quality.

Eighteen alluvial aquifer wells were evaluated during 1992–2012 and 2010–2012 (WDEQ-LQD 2014). 

Groundwater quality data were also collected from the WDEQ-LQD Hydrology Database for the period 

from 1992–2012. For the 1992–2012 period, Class III exceedances were noted for aluminum (one well), 

boron (one well), chloride (10 wells), chromium (one well), copper (two wells), nitrite + nitrate as N (one 

well), selenium (seven wells), sulfate (nine wells), TDS (13 wells), and pH (two wells). For the 2010–

2012 period, exceedances were observed for chloride (10 wells), nitrite + nitrate as N (one well), 

selenium (two wells), sulfate (eight wells), and TDS (13 wells). TDS over the 2010–2012 period ranged 

from 610 to 30,000 mg/L, with a median of 7,280 mg/L. The minimum TDS was observed at the Randor 

Springs well north of the Bridger Mine Complex and the maximum TDS was observed at well 455485 

along Bitter Creek at the Black Butte Mine. The overall results indicate that several wells in the alluvial 

aquifer exceed WDEQ-WQD Class III livestock standards for several constituents, particularly along 

Bitter Creek. The alluvial aquifer has poorest water quality among the aquifers of concern in the 

groundwater impact analysis area.
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Groundwater quality data were collected from 18 overburden wells during 2010–2012 (WDEQ-LQD 

2014). Groundwater quality data were also collected from the WDEQ-LQD Hydrology Database for the 

period from 2005–2012. For the entire during-mining period (2001–2012) in the Fort Union Formation 

overburden, Class III exceedances were noted for pH (10 wells). For the 2010–2012 period, pH showed 

exceedances at two wells. TDS over 2010–2012 ranged from 510 to 1,990 mg/L, with a median of 1,120 

mg/L. For the entire during-mining period (2005–2012) in the Almond Formation overburden, Class III 

exceedances were noted for pH (one well) and selenium (one well). For the 2010–2012 period, selenium 

showed one exceedance at one well. TDS over 2010–2012 ranged from 740 to 2,200 mg/L, with a median 

of 1,500 mg/L. The overall results from the overburden monitoring wells in both the Fort Union 

Formation and Almond Formation indicate good water quality that generally meets WDEQ-WQD Class 

III livestock standards. Periodic exceedances of pH occur in both formations, and for selenium in the 

Almond Formation overburden. Water quality in the overburden formations is better than quality in the 

alluvial and backfill monitoring wells.

Groundwater quality data were collected from 12 coal aquifer wells during 2010–2012 (WDEQ-LQD 

2014). Groundwater quality data were also collected from the WDEQ-LQD Hydrology Database for the 

period from 1992–2012. For the entire during-mining period (1992–2012) in the Fort Union Formation 

coal, Class III exceedances were noted for sulfate (one well), TDS (one well), and pH (two wells). For the 

2010–2012 period, pH showed one exceedance at one well. TDS over 2010–2012 ranged from 280 to 

1,600 mg/L, with a median of 1,395 mg/L. For the entire during-mining period in the Almond Formation 

coal (1986–2012), Class III exceedances were noted for chromium (one well), selenium (one well), and 

pH (three wells). For the 2010–2012 period, pH showed two exceedances at one well. TDS over 2010–

2012 ranged from 442 to 1,530 mg/L, with a median of 974 mg/L. For the entire during-mining period in 

the Lance Formation coal (1992–2012), Class III exceedances were noted for chloride (one well), 

selenium (three wells), sulfate (one well), TDS (two wells), and pH (three wells). For the 2010–2012 

period, exceedances were noted for chloride (one well), selenium (three wells), TDS (one well), and pH 

(two wells). TDS over 2010–2012 ranged from 1,450 to 11,300 mg/L, with a median of 4,120 mg/L. The 

overall results from the coal monitoring wells indicate water quality is slightly poorer in the Lance 

Formation coal, although much of this is driven by high dissolved ions at one well at the Black Butte 

Mine (well 305381). The Lance Formation coal wells also contain higher concentrations of selenium 

compared to the Fort Union Formation and Almond Formation coal wells.

Groundwater quality data were collected from 14 underburden wells during 2010–2012 (WDEQ-LQD 

2014). Groundwater quality data were also collected from the WDEQ-LQD Hydrology Database for the 

period from 2001–2012. For the entire during-mining period (2001–2012) in the Fort Union Formation 

underburden, Class III exceedances were noted for mercury (one well) and pH (one well). For the 

2010–2012 period, there were no exceedances of Class III standards. TDS over 2010–2012 ranged from 

1,880 to 2,020 mg/L, with a median of 1,990 mg/L. For the entire during-mining period in the Almond 

Formation underburden (2005–2012), Class III exceedances were noted for selenium (one well) and pH 

(two wells). For the 2010–2012 period, pH showed four exceedances at one well. TDS over 2010–2012 

ranged from 1,490 to 3,140 mg/L, with a median of 1,790 mg/L. For the entire during-mining period in 

the LF underburden (2001–2012), Class III exceedances were noted for aluminum (one well) and pH (10 

wells). For the 2010–2012 period, 21 exceedances were noted for pH at eight wells. TDS over 2010–2012 

ranged from 960 to 1,960 mg/L, with a median of 1,485 mg/L. The overall results from the underburden 

monitoring wells indicate water quality is high and generally meets WDEQ-WQD Class III livestock 

standards. Some wells in each underburden formation show slight exceedances of pH, and one Almond 

Formation well at the Black Butte Mine (SW4-UB) has shown recent exceedances of the Class III 

selenium criterion.
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Groundwater quality data were collected from three Ericson wells during 2010–2012 (WDEQ-LQD 

2014). For the entire during-mining period, Class III exceedances were noted for pH (four wells). For the 

2010–2012 period, exceedances were observed for pH at two wells. TDS over 2010–2012 ranged from 

410 to 1,270 mg/L, with a median of 1,010 mg/L. The overall results indicate water quality in the Ericson 

Sandstone is high and meets WDEQ-WQD Class III livestock standards, with the exception of periodic 

exceedances of pH.

Groundwater quality data were collected from seven backfill aquifer wells during 2010–2012 (WDEQLQD 2014). For the entire during-mining period, Class III exceedances were noted for boron (two wells), 

chloride (five wells), chromium (two wells), lead (one well), nitrite + nitrate as nitrogen (one well), 

selenium (four wells), sulfate (eight wells), TDS (10 wells), and pH (three wells). For the 2010–2012 

period, exceedances were observed for boron (one well), chloride (one well), selenium (one well), sulfate 

(three wells), TDS (four wells), and pH (two wells). TDS over 2010–2012 ranged from 2,080 to 13 800 

mg/L, with a median of 6,170 mg/L. The minimum TDS was observed at Bridger Mine Complex well 

SP-09-01 and the maximum TDS was observed at Black Butte Mine well 566394. The backfill aquifer 

currently has poorer water quality compared to the overburden-Fort Union Formation, overburdenAlmond Formation, coal-Fort Union Formation, coal-Almond Formation, coal-Lance Formation, 

underburden-Fort Union Formation, underburden-Almond Formation, underburden-Lance Formation, and 

Ericson Sandstone aquifers, but better quality than the alluvial aquifer.

3.12. Wetlands and Riparian Zones

The impact analysis area for wetlands and riparian zones is the 560-acre project area. This area was 

chosen because the potential impacts to wetlands and riparian zones would generally be limited to the 

footprint of the proposed surface mining activities and would not extend beyond the mining plan

modification area boundary.

3.12.1. Wetlands

The surface water in the wetlands and riparian zones impact analysis area occurs as ephemeral streams, 

which flow only as a result of precipitation. However, the drainage known as Tenmile Draw located in 

Section 12 has an established riparian area. There are unnamed tributaries and other draws in the analysis 

area that are dominated by upland species of big sagebrush, sticky-leaved rabbitbrush, and western 

wheatgrass and do not support wetland characteristics (BKS 2012c). There are no National Wetlands 

Inventory (NWI) wetlands identified in the wetlands and riparian zones impact analysis area.

3.12.2. Riparian Zones

There are approximately 11,808 feet of ephemeral streams, no perennial streams, and 43.7 acres of 

Western Great Plains Riparian Woodland and Shrubland land cover type in the wetlands and riparian 

zones impact analysis area. The majority (approximately 90%) of the wetlands and riparian zones impact 

analysis area is covered by the Inter-Mountain Basins Big Sagebrush Shrubland (374.0 acres) and 

Inter-Mountain Basins Mixed Salt Desert Scrub (128.3 acres) land cover types.
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4. ENVIRONMENTAL CONSEQUENCES 

4.1. Introduction

In accordance with 40 CFR 1502.16, this chapter presents the anticipated environmental consequences of 

the Proposed Action and No Action Alternative on the affected environment. 

For the purposes of this document, an environmental impact is defined as a change in the quality and/or 

quantity of a given resource due to a modification in the existing environment from the Proposed Action. 

Impacts may be beneficial or adverse, direct or indirect, and of short-term or long-term duration. Unless 

otherwise specified, short term is defined as the time period required to mine the project area, estimated to 

be approximately 21 years. Long-term impacts are those that would occur or remain after this time. Direct 

impacts are caused by the action and occur at the same time and place, and indirect impacts from an 

action occur later in time and/or are removed in space. Although both direct and indirect impacts are 

discussed in this EA, they are not differentiated because it can be difficult to distinguish between the two.

Impacts may vary in degree from a slightly discernible change in the environment to a total change in the 

environment. The significance of these impacts is determined using the criteria set forth by CEQ (40 CFR 

1508.27) and the professional judgment of the specialists doing the analyses; it is assessed using the two 

key elements of context and intensity. The context where impacts occur can be local, regional, and 

national. Intensity refers to the severity of the effect. Impacts can be beneficial (positive) or adverse 

(negative). Impacts are described by their level of significance (i.e., major, moderate, minor, negligible, or 

no impact). For purposes of discussion and to enable use of a common scale for all resources, resource 

specialists considered the following impact levels in qualitative terms.

Major Impact: Impacts that potentially could cause irretrievable loss of a resource; significant 

depletion, change, or stress to resources; or stress within the social, cultural, and economic 

realm.

Moderate Impact: Impacts that potentially could cause some change or stress to an 

environmental resource but the impact levels are not considered significant.

Minor Impact: Impacts that potentially could be detectable but slight.

Negligible Impact: Impacts in the lower limit of detection of an effect that potentially could 

cause an insignificant change or stress to an environmental resource or use.

No Impact: No discernable or measurable impacts.

This EA uses generally available environmental data and data collected in the project area to predict 

environmental effects that could result from the Proposed Action and No Action Alternative. A level of 

uncertainty is associated with any set of data in terms of predicting outcomes, especially when natural 

systems are involved. The predictions described in this analysis are intended to allow comparison of the 

No Action Alternative to the Proposed Action, as well as to provide a method to determine whether 

activities proposed by the applicant would be expected to comply with applicable federal, state, and local 

regulations.
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4.2. Air Quality and Climate Change 

4.2.1. Proposed Action 

4.2.1.1. DIRECT AND INDIRECT IMPACTS

4.2.1.1.1. Air Quality

Emissions of air pollutants at the Bridger Mine Complex are currently regulated and limited by air quality 

permits issued by WDEQ-AQD (Air Quality Permits MD-9156 and MD-12225). Any federal coal 

produced by anticipated surface mining methods in the proposed modification would replace coal 

previously produced in other portions of the Bridger Mine Complex, with no resulting change in overall 

annual coal production. Because the Proposed Action is a continuation of existing surface mining and not 

an increase in the mining rate or an increase in production levels at the mine, no permit modifications 

would be required. Mining of the project area would occur under the existing air quality permits. The 

Proposed Action would not require a change in already permitted actions or in production levels and there 

would be no direct incremental increase in annual emissions from implementation of the Proposed 

Action.

Under the Proposed Action, direct emission sources are divided into three categories: fugitive emissions 

(particulate matter from excavation, hauling, and reclamation activities; NOx, CO, and SO2 from 

blasting), tailpipe emissions (criteria pollutant and HAP emissions from vehicles), and process emissions 

(particulate matter from coal processing). Major fugitive emission sources include the following:

Pit surface mining of an area approximately 104 acres in size through truck-shovel prestripping, dragline excavation, scraper and front-end loader excavation, overburden drilling and 

blasting, dozer excavation, and grading for reclamation 

Any topsoil, overburden, and coal stockpiles located in the project area 

Travel on unpaved access and haul roads in the project area

The primary tailpipe emission sources include the following:

Vehicles used by employees and occasional delivery trucks coming to and from the project area

Water trucks, scrapers, front-end loaders, dozers, and graders used in the project area

Once the coal has been excavated, it would be hauled to other parts of the Bridger Mine Complex for 

processing. Process emissions include the following: 

Coal truck dumps 

Coal transfer points

Primary crushers

Coal hauling in trucks

Coal hauling with the overland conveyor 

The Proposed Action would not result in an annual production increase but would add approximately 13 

additional years to the life of the mine, when combined with future mining on adjacent lands. Activity 

levels and equipment use at the surface mine would remain the same but would transition into the project 

area from mined-out areas. Employee levels would remain essentially unchanged. Fugitive, process, and 

tailpipe emissions from the sources described above would remain at or near current levels. Emissions 
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under the Proposed Action would continue at the levels quantified in Table 3-4. No NAAQS or WAAQS 

exceedances are expected to occur. Because the Proposed Action would be a continuation of mining and 

would occur under the Bridger Mine Complex’s existing air permits and because of the particulate 

monitoring system and contingency action plan, direct emission impacts from mining activities are 

expected to be short-term and minor.

Indirect effects from the burning of the coal removed from the project area are estimated by using 

emissions from the Jim Bridger Power Plant. The annual coal throughput at the Jim Bridger Power Plant in 

2015 was 7,613,893 tons. The project area has approximately 4.5 million tons of economically recoverable 

federal coal; the total time needed to remove the coal from the project area is anticipated to be 21 years 

(2017–2037). Assuming the coal is excavated at a steady rate over the 21-year time period, approximately 

214,286 tons of coal2 from the project area would be burned at the Jim Bridger Power Plant each year. This 

represents approximately 2.8% of the annual coal throughput at the plant. Using the Jim Bridger Power 

Plant’s 2015 emission inventory (see Table 3-6), and assuming that the coal from the project area is equal 

to 2.8% of the power plant’s annual coal throughput, emissions from burning of the coal from the project 

area are presented in Table 4-1. These indirect emissions would not change overall emission levels at the 

power plant because any federal coal produced by anticipated surface mining methods in the proposed 

modification would replace coal previously produced in other portions of the Bridger Mine Complex, 

with no resulting change in overall Bridger Mine Complex annual coal production. Therefore, there 

would be no noticeable change in the delivery of coal from the Bridger Mine Complex to the Jim Bridger 

Power Plant.

Table 4-1. Estimated Emissions Associated with the Burning of Federal Coal from the Project Area at the 

Jim Bridger Power Plant

Pollutant Annual Emissions* (tons per year) Total Emissions† (tons)

CO 140 2,944

NOx 384 8,058

PM10 20 415

PM2.5 6 130

PM 39 823

SO2 287 6,036

VOCs 6 134

HAPs 4 85

Ammonia 0.1 2

Note: Data for this table was calculated without rounding; however, the annual and total emissions columns have been rounded. 

*Annual emissions are calculated by multiplying the Jim Bridger Power Plant 2015 emissions in Table 3-6 by 2.8%, to reflect the percentage of coal 

burned that would be attributable to the Proposed Action. 

† Annual emissions are multiplied by 21 (the total number of years needed to remove the coal) to calculate total emissions attributable to the Proposed 

Action

When burned, the coal mined from the project area would indirectly contribute to criteria pollutant 

emissions, HAP and other toxic air pollutant emissions, acid or mercury deposition impacts, and CCW

caused by the Jim Bridger Power Plant. It would be very difficult to separate out which indirect impacts 

are specifically caused by the burning of coal from the Proposed Action for this EA. No known data are 

available for acid or mercury deposition impacts caused by emissions from the Jim Bridger Power Plant. 

 2 The 214,286 tons of coal do not include coal from mining on adjacent private lands (the 700,000 tons of coal described in 

Sections 1.2 and 2.2.1 include coal from mining on adjacent private lands).
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No data were identified that quantify pollution impacts on soil and vegetation from the power plant. Jim 

Bridger Power Plant appears to have implemented appropriate pollutant control technology which is 

intended to reduce potential emission impacts to the surrounding environment. Inspection data for Jim 

Bridger’s management of CCW indicate that the ponds are generally in satisfactory condition, with 

acceptable maintenance and surveillance programs. Based on this information and based on the fact that

federal coal produced from the project area would replace coal previously produced in other portions of 

the Bridger Mine Complex (there would be no resulting change in overall Bridger Mine Complex annual 

coal production and delivery to the Jim Bridger Power Plant, and no change to the Jim Bridger Power 

Plant’s production rate), indirect impacts from the burning of federal coal from the project area are 

expected to be short-term and minor.

4.2.1.1.2. Climate Change

Impacts of the Proposed Action on Climate Change

The projected GHG emissions associated with the Proposed Action were used as a proxy for assessing the 

Proposed Action’s potential effects on climate change. This is because there is no available standard 

methodology to determine how a project’s incremental contribution of GHG emissions would result in 

physical effects on the environment, either locally or nationally. Section 3.3.3 contains a summary 

discussion of general GHG emission impacts, while this section provides projected GHG emissions from 

the Proposed Action. 

The coal from the project area that would be burned at the Jim Bridger Power Plant would not change the 

GHG emission levels at the power plant, because it would replace coal previously produced in other 

portions of the Bridger Mine Complex (there would be no resulting change in overall Bridger Mine 

Complex annual coal production and delivery to the Jim Bridger Power Plant, and no change to the Jim 

Bridger Power Plant’s production rate). However, this analysis estimates GHG emissions from the off-site 

burning of the coal from the project area to account for indirect emissions.

BCC estimates that the project area has approximately 4.5 million tons of economically recoverable coal. 

Table 4-2 shows the estimated greenhouse gas emissions associated with the burning of this quantity of 

coal, based on EPA’s Equation 2 (EPA 2016j):

Emissions (mass of GHG emitted) = Fuel (mass of fuel combusted) × Fuel Heat Content 

(units of energy per mass of fuel) × Emission Factor (GHG emission factor per energy unit) 

Table 4-2. Estimated GHG Emissions Associated with Burning of Federal Coal from the Project Area

GHG

Mass of Fuel 

Combusted 

(million tons)

Fuel Heat Content at 

Bridger Mine Complex 

(MMBTU/ton)

Emission Factor for 

Sub-bituminous Coal*

Total 

Emissions 

(kg)

Total 

Emissions

(metric tons)

Total CO2e 

Emissions†

(metric tons)

CO2 4.5 18.4 97.17 kilograms 

CO2/mmBtu

8,045,676,000 8,045,676 8,045,676

CH4 4.5 18.4 11 grams CH4/mmBtu 910,800 911 32,796

N2O 4.5 18.4 1.6 grams N2O/mmBtu 132,480 132 39,336

Total - - - - - 8,117,808

As shown in Table 4-2, total GHG emissions from burning the coal excavated from the project area would 

be 8,117,808 metric tons CO2e. Note that the 8,117,808 metric tons CO2e would be emitted over a 21-

year period. Assuming the coal is excavated at a steady rate over this time period, this comprises 386,562
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metric tons of CO2e emissions per year. This indirect impact is expected to be long-term and moderate, 

when compared to the Jim Bridger Power Plant’s total 2015 CO2e emissions of 13,229, 723 metric tons 

(the Proposed Action’s annual CO2e emissions are 2.9% of the Jim Bridger Power Plant’s annual 2015 

CO2e emissions) (EPA 2015a). For additional context, the Naughton Power Plant in adjacent Lincoln 

County emitted 5,112,600 metric tons of CO2e in 2015 (the Proposed Action’s annual CO2e emissions are 

7.6% of the Naughton Power Plant’s annual 2015 CO2e emissions) (EPA 2015a). The total energy-related 

CO2 emissions in Wyoming in 2014 was approximately 65.6 million metric tons, the total energy-related 

CO2 emissions in the climate change analysis area was approximately 1,040.5 million metric tons in 2014,

and the total energy-related CO2 emissions in the United States in 2014 was approximately 5,482.2 

million metric tons (EIA 2017). In comparison to these 2014 emissions totals, the approximately 386,562 

metric tons CO2e projected to be emitted annually by the combustion of coal excavated from the project 

area would represent approximately 0.6% of the energy-related CO2 emitted annually in Wyoming, 

approximately 0.04% of the energy-related CO2 emitted annually in the climate change analysis area, and 

approximately 0.007% of the energy-related CO2 emitted annually in the United States.

Impacts of Climate Change on the Proposed Action

The USGS Climate Change Viewer provides information on climate change impacts at local to regional 

scales and enhances understanding of possible future climate patterns and climate impacts at a local scale. 

The Climate Change Viewer is used in this analysis to predict the indirect impacts of climate change on 

the Proposed Action. Final reclamation at the Bridger Mine Complex is expected to be completed by 

2046; therefore, the time period selected for the Climate Change Viewer projections was 2025–2049. 

Climate and water balance projections for Sweetwater County are shown in Table 4-3. 

Table 4-3. USGS Climate Change Viewer Projections for Sweetwater County

Variable Sweetwater County Climate and Water Balance Projections*

1950–2005 (Historical Period) 2025–2049 (Future Period) Change

Climate Changes

Annual Mean Maximum 

Temperature

55.0°F 59.2°F 4.1°F

Annual Mean Minimum 

Temperature

27.3°F 31.6°F 4.3°F

Annual Mean Precipitation 0.024 inch/day 0.024 inch/day 0.0 inch/day

Water Balance Changes

Annual Mean Snow† 0.3 inch 0.2 inch −0.1 inch

Annual Mean Soil StorageŦ 0.5 inch 0.4 inch −0.1 inch

Annual Mean Evaporative Deficit§ 1.0 inch/month 1.2 inches/month 0.2 inch/month

Source: USGS (2015)

Note: °F = degrees Fahrenheit. No annual changes to runoff would occur.

* Projections are based on the mean model and Representative Concentration Pathway 8.5 (the most aggressive emissions scenario).

† Snow water equivalent: the liquid water stored in the snowpack

Ŧ Soil water storage: the water stored in the soil column

§ Evaporative deficit: the difference between potential evapo-transpiration if unlimited water were available and actual evapo-transpiration

The Proposed Action would be completed in 2037 and would not necessarily be subject to the full extent 

of the potential impacts shown in Table 4-3. Overall Bridger Mine Complex reclamation activities, which 

would include reclamation of areas mined in the Proposed Action, would be completed in 2046. The exact 
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period of reclamation for mining conducted under the Proposed Action is not known because it is 

dependent on the mine plan and mining sequence. This analysis assumes that the projections shown in 

Table 4-3 would affect the Proposed Action and associated reclamation.

During the 21-year time period it would take to remove the coal from the project area, natural weather 

variations could result in dryer or wetter years. However, as shown in Table 4-3, the overall trend in 

Sweetwater County would be warmer and drier. The potential changes to climate and the water balance 

could impact water resources, soil erosion, vegetation, and reclamation in the analysis area.

Surface water impacts from climate change could be offset by the potential for Proposed Action mining 

activities to increase surface water runoff. However, it is also possible that mining activities would 

decrease surface water runoff (see Section 4.10.1). In this case, climate change would amplify any 

decrease caused by the Proposed Action. Overall, water monitoring stations in the analysis area indicate 

that mining impacts to surface water have been minimal (and short term). Based on this information, the 

impact of climate change on the Proposed Action with regard to surface water is expected to be 

negligible. 

In general, coal mining at the Bridger Mine Complex and other nearby coal mines (e.g., Black Butte) is 

expected to lower the groundwater level to some extent (WDEQ-LQD 2014). The Proposed Action is 

expected to have local impacts on groundwater in the alluvial aquifer but minimal impacts on the 

overburden, coal seam, and underburden aquifers (see Section 4.10.1.1.2). A warmer and drier climate 

could contribute to reduced groundwater recharge and amplify any Proposed Action impacts to the 

alluvial aquifer. Impacts are expected to be minor based on the overall low intensity of mining impacts to 

groundwater.

Under the Proposed Action, 104 acres of soils (18.6% of the project area) would be directly disturbed by 

surface mining. Surface-mining activities would disturb soil productivity, texture, structure, and porosity 

through the large-scale removal, stockpiling, and replacement of soils during surface mining. Because of 

the soil’s degradation characteristics (water and wind erosion hazard, drought susceptibility, rooting 

depth, excess salt, excess sodium) (see Section 3.8), there is an increased risk of erosion impacts from 

Proposed Action surface mining. A warmer and drier climate could amplify soil susceptibility to erosion. 

However, this risk would be negligible because of by BCC’s sediment control system (see Section 

4.7.1.1).

Approximately 104 acres of vegetation (18.6% of the project area) would be directly disturbed by surface 

mining under the Proposed Action. Following the completion of mining, mined areas would be backfilled 

and regraded, then topped with the stockpiled soils and revegetated. Newly applied topsoil would 

typically be revegetated the following spring and/or fall with a mixture of mostly native grasses, forbs, 

and shrubs. Seed mixes would be selected based on pre-mining vegetation communities, post-mining land 

use, seed availability, timing, topography, soil characteristics, and other site-specific considerations. Seed 

mix species selected for reclamation have significant browse, livestock and/or wildlife forage, or cover 

value and are adapted to the region (see Section 4.9.1.1). A vegetation monitoring program would also be 

conducted over the life of the mine to aid in determining when the post-mining land use of undeveloped 

rangeland is met (BCC 2016). Climate change impacts as shown in Table 4-3 could reduce reclamation 

success. These changes could result in the need to consider different plant species during reclamation to 

account for higher temperatures. The vegetation monitoring program would provide real-time data to 

respond to any climate change-caused impacts; based on this program, the indirect impact of climate 

change on reclamation would be negligible.
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Social Cost of Carbon

A protocol to estimate what is referenced as the “social cost of carbon” (SCC) associated with GHG 

emissions was developed by a federal Interagency Working Group (IWG), to assist agencies in addressing 

Executive Order (EO) 12866, which requires federal agencies to assess the cost and the benefits of 

proposed regulations as part of their regulatory impact analyses. The SCC is an estimate of the economic 

damages associated with an increase in carbon dioxide emissions and is intended to be used as part of a 

cost-benefit analysis for proposed rules. As explained in the Executive Summary of the 2010 SCC 

Technical Support Document “the purpose of the [SCC] estimates...is to allow agencies to incorporate 

the social benefits of reducing carbon dioxide (CO2) emissions into cost-benefit analyses of regulatory 

actions that have small, or ‘marginal,’ impacts on cumulative global emissions.” Technical Support 

Document: Social Cost of Carbon for Regulatory Impact Analysis Under Executive Order 12866 

February 2010 (withdrawn by EO13783). While the SCC protocol was created to meet the requirements 

for regulatory impact analyses during rulemakings, there have been requests by public commenters or 

project applicants to expand the use of SCC estimates to project-level NEPA analyses.

The decision was made not to expand the use of the SCC protocol for this Jim Bridger Mine EA for a 

number of reasons. Most notably, this action is not a rulemaking for which the SCC protocol was 

originally developed. Second, on March 28, 2017, the President issued Executive Order 13783 which, 

among other actions, withdrew the Technical Support Documents upon which the protocol was based and 

disbanded the earlier Interagency Working Group on Social Cost of Greenhouse Gases. The Order 

further directed agencies to ensure that estimates of the social cost of greenhouse gases used in regulatory 

analyses “are based on the best available science and economics” and are consistent with the guidance 

contained in OMB Circular A-4, “including with respect to the consideration of domestic versus 

international impacts and the consideration of appropriate discount rates” (E.O. 13783, Section 5(c)). In 

compliance with OMB Circular A-4, interim protocols have been developed for use in the rulemaking 

context. However, the Circular does not apply to project decisions, so there is no Executive Order 

requirement to apply the SCC protocol to project decisions.

Further, the National Environmental Policy Act (NEPA) does not require a cost-benefit analysis (40 

C.F.R. § 1502.23), although NEPA does require consideration of “effects” that include “economic” and 

“social” effects. 40 C.F.R. 1508.8(b). Without a complete monetary cost-benefit analysis, which would 

include the social benefits of the proposed action to society as a whole and other potential positive 

benefits, inclusion solely of an SCC cost analysis would be unbalanced, potentially inaccurate, and not 

useful in facilitating an authorized officer’s decision. Any increased economic activity, in terms of 

revenue, employment, labor income, total value added, and output, that is expected to occur with the 

proposed action is simply an economic impact, rather than an economic benefit, inasmuch as such 

impacts might be viewed by another person as negative or undesirable impacts due to potential increase in 

local population, competition for jobs, and concerns that changes in population will change the quality of 

the local community. Economic impact is distinct from “economic benefit” as defined in economic theory 

and methodology, and the socioeconomic impact analysis required under NEPA is distinct from costbenefit analysis, which is not required.

Finally, the SCC, protocol does not measure the actual incremental impacts of a project on the 

environment and does not include all damages or benefits from carbon emissions. The SCC protocol 

estimates economic damages associated with an increase in carbon dioxide emissions - typically 

expressed as a one metric ton increase in a single year - and includes, but is not limited to, potential 

changes in net agricultural productivity, human health, and property damages from increased flood risk 

over hundreds of years. The estimate is developed by aggregating results “across models, over time, 

across regions and impact categories, and across 150,000 scenarios” (Rose et al. 2014). The dollar cost 
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figure arrived at based on the SCC calculation represents the value of damages avoided if, ultimately, 

there is no increase in carbon emissions. But the dollar cost figure is generated in a range and provides 

little benefit in assisting the authorized officer’s decision for project level analyses. For example, in a 

recent environmental impact statement, OSM estimated that the selected alternative had a cumulative 

SCC ranging from approximately $4.2 billion to $22.1 billion depending on dollar value and the discount 

rate used. The cumulative SCC for the no action alternative ranged from $2.0 billion to $10.7 billion. 

Given the uncertainties associated with assigning a specific and accurate SCC resulting from 13

additional years of operation under the mining plan modification, and that the SCC protocol and similar 

models were developed to estimate impacts of regulations over long time frames, this EA quantifies direct 

and indirect GHG emissions and evaluates these emissions in the context of U.S. and State/County GHG 

emission inventories as discussed in Section 4.2.1.1.2 of the EA. 

To summarize, this EA does not undertake an analysis of SCC because 1) it is not engaged in a 

rulemaking for which the protocol was originally developed; 2) the IWG, technical supporting 

documents, and associated guidance have been withdrawn; 3) NEPA does not require cost-benefit 

analysis ; and 4) the full social benefits of coal-fired energy production have not been monetized, and 

quantifying only the costs of GHG emissions but not the benefits would yield information that is both 

potentially inaccurate and not useful.

4.2.2. No Action Alternative 

4.2.2.1. DIRECT AND INDIRECT IMPACTS

Under the No Action Alternative, OSMRE would recommend that the ASLM disapprove the proposed 

mining plan modification and there would be no extraction of recoverable coal in the project area. 

Therefore, there would be no direct or indirect impacts to air quality and climate change from surface 

mining activities in the mining plan modification area. However, existing mining activities in the adjacent 

Bridger Mine Complex would continue to emit pollutants that affect air quality and climate change

through approximately 2025, as would other current emission sources in the analysis area such as the Jim 

Bridger Power Plant. Current ambient air quality conditions in the analysis area, which would continue to 

occur under the No Action Alternative, are shown in Table 3-3; they are in compliance with the NAAQS 

and WAAQS. Current emissions from the Jim Bridger Power Plant, which would also continue to occur 

under the No Action Alternative, are shown in Table 3-6.

4.3. Cultural Resources

4.3.1. Proposed Action

4.3.1.1. DIRECT AND INDIRECT IMPACTS

4.3.1.1.1. Known Cultural Resources

Surface disturbance would occur on 104 acres of the project area. Actions that cause surface and 

subsurface physical disturbance could result in the direct damage, destruction, or inadvertent discovery of 

cultural resources. Any direct or indirect impacts that result in the damage or destruction of cultural 

resources would be permanent. Impacts would include the loss of research potential and interpretation 

possibilities. 
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A cultural resources inventory performed in Section 12 resulted in the discovery of five newly identified

sites, nine previously recorded sites, and four isolated artifacts. None of these sites are eligible for 

nomination to the NRHP and no further action was recommended (WAS 2009). A segment of the 

Cherokee Trail, Evans Variant, that crosses the south half of Section 12 was also evaluated and found to 

be non-contributing to the NRHP eligibility of the Cherokee Trail. No significant trail remains would be 

affected by the Proposed Action and no further work was recommended (WAS 2010).

A cultural resources inventory was also performed in Section 24, identifying one previously recorded site 

(48S13859). No newly identified cultural resource properties were in this section of the project area. Site 

48S13859 was recommended not eligible for the NRHP and no further work was recommended (WAS 

2008). Although the Evans Variant segment of the Cherokee Trail that crosses the south half of Section 

12 may be impacted by the Proposed Action, it is a non-contributing element to the NRHP eligibility of 

the Cherokee Trail and there would be no adverse effect.

Based on the results of the cultural resource inventories, the Proposed Action would have no adverse 

effect (no impact) on any cultural resources eligible for the NRHP.

According to the mine plan for the Bridger Mine Complex, if unrecorded cultural resources are 

encountered during mining operations, activity that has the potential to impact those resources would

cease, and the BLM archaeologist would be notified (the mine plan decision document for this EA, if the 

Proposed Action is approved, would also include the condition that OSMRE and WDEQ-LQD be 

notified). The cultural remains would then be recorded and evaluated. If significant cultural remains are 

inadvertently affected during mining operations, salvage or data recovery excavations may be required to 

mitigate the adverse effects to the resources. The mine plan also outlines procedures to follow if human 

remains are discovered (BCC 2016).

4.3.1.1.2. Native American Religious Concerns

No comments were received on the Proposed Action from any Native American tribe. No Native 

American religious concerns have been identified; therefore, the Proposed Action would have no impact 

on Native American religious concerns.

4.3.2. No Action Alternative

4.3.2.1. DIRECT AND INDIRECT IMPACTS

Under the No Action Alternative, OSMRE would recommend that the ASLM disapprove the proposed 

mining plan modification and there would be no extraction of recoverable coal in the project area. As 

such, no new surface coal mining activity would be conducted under this alternative, and no cultural 

resources in the mining plan modification area would be directly or indirectly affected.
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4.4. Fish and Wildlife

4.4.1. Proposed Action

4.4.1.1. DIRECT AND INDIRECT IMPACTS

4.4.1.1.1. Common Wildlife

Under the Proposed Action, there would be 104 acres of surface disturbance from mining activities. This 

surface disturbance would affect vegetation types (grasses, forbs, sagebrush, etc.) and ephemeral streams

that are associated with common wildlife such as birds, small rodents, jackrabbits, coyotes, reptiles, and 

amphibians. The proposed surface mining activities would result in direct impacts to wildlife that include 

a loss of habitat and an increased potential of mortality for less-mobile species, from being struck by 

mining equipment or vehicles. 

The proposed surface mining activities would also have direct impacts on wildlife species through 

increased noise and human activity. Increased human activity could cause some localized avoidance of 

areas adjacent to mining activities, which could affect foraging and other wildlife behaviors. Noise can 

impact wildlife in several ways, as follows (Lynch et al. 2011): 

Noise can interfere with acoustical awareness by temporarily deafening animals, especially those 

close to the source, with very loud sounds or by distracting animals with less dramatic noises. 

Distraction can be especially detrimental if the typical predation or foraging pattern of the animal 

is altered, such as the coyote being unable to catch a prey item. Repeated distractions can lead to 

a reduction in individual health and ultimately in the health and success of the population. 

Noise can add to existing sound levels and reduce the range at which signals can be detected, 

identified, and localized (masking). Masking can increase predation rates for colonial species, 

such as prairie dogs and ground squirrels, if warnings indicating the presence of a predator are not 

heard by other individuals. 

Prolonged exposure to noise has been shown to cause some wildlife, such as mule deer and 

songbirds, to avoid certain areas, reducing already limited suitable habitat. Displacement due to 

noise has also been shown to impact songbirds by reducing pairing success, bird density, and 

biodiversity of birds in the area. 

Indirect impacts on wildlife resulting from the proposed surface mining activities include long-term 

alterations in the mining plan modification area’s topography and vegetation cover and diversity after the 

area is mined and reclaimed. For example, there would be a reduction in sagebrush density that would 

cause a decrease in carrying capacity for some wildlife species until the sagebrush gradually becomes 

reestablished on the reclaimed land.

BCC’s existing mine permit includes a wildlife monitoring and protection program that was designed to 

allow assessment of the wildlife response to development of mining activities and reclamation efforts. 

Through the wildlife monitoring program, BCC identifies any substantial wildlife/mining conflicts and 

potential conflicts within its permit boundary. If conflicts develop or are anticipated, mitigation programs 

are designed and implemented to relieve or offset the expected impacts. This wildlife monitoring and 

protection program would be applied to the mining plan modification area as well. The methodologies of 

the wildlife monitoring and protection program follow those found in WDEQ-LQD Coal Rules and 

Regulations, Appendix B. Information gathered from the wildlife monitoring and protection program is 

included in BCC’s WDEQ-LQD Annual Report. Given the availability of habitat in the fish and wildlife 

impact analysis area, as well as the wildlife monitoring program that would be part of the mine permit, 

impacts to common wildlife under the Proposed Action are expected to be short-term and minor. 
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4.4.1.1.2. Big Game

Under the Proposed Action, the proposed surface mining activities would cause approximately 104.1 

acres of surface disturbance in winter/year-long mule deer habitat and year-long elk habitat. The proposed 

surface mining activities would also cause approximately 77.6 acres of surface disturbance in crucial, 

winter/year-long pronghorn antelope habitat, as well as 26.5 acres of surface disturbance in winter/yearlong pronghorn antelope habitat. The acres of impact in each type of big game habitat represents 3.1% of 

the total acres of these types of habitat available in the fish and wildlife analysis area. These acres would 

be generally unavailable as habitat until the completion of reclamation activities.

The impacts to big game from increased noise and human activity that result from the proposed surface 

mining activities would be the same in nature as those described for common wildlife in Section 4.4.1.1.1.

Given the availability of habitat in the fish and wildlife impact analysis area, as well as the wildlife 

monitoring program that would be part of the mine permit, impacts to big game under the Proposed 

Action are expected to be short-term and minor.

4.4.1.1.3. Migratory Birds, including Raptors

Under the Proposed Action, the proposed surface mining activities would cause approximately 104 acres 

of surface disturbance in vegetation types commonly used by migratory birds. BCC’s existing mine 

permit requires a breeding bird survey that is conducted twice each spring to record migratory birds of 

high federal interest. The existing permit also requires annual nest surveys in areas of raptor concentration 

near the permit area. These surveys would also be required for the mining plan modification area. BCC’s 

existing permit also contains a Raptor Mitigation Plan, which would be applied to the mining plan 

modification area. Given the availability of habitat in the fish and wildlife impact analysis area, as well as 

the surveys and mitigation plan that would be part of the mine permit, the impacts to migratory birds and 

raptors under the Proposed Action are expected to be short-term and minor.

4.4.1.1.4. Fish

Under the Proposed Action, the proposed surface mining activities are expected to have minimal impacts 

on surface water quantity and quality, and thus, minimal impacts on any fish in the ephemeral and 

intermittent streams in the fish and wildlife impact analysis area. However, as stated in Section 3.5.4, all 

of the streams in the fish and wildlife impact analysis area are ephemeral or intermittent streams that are 

unlikely to support fish populations. The WGFD does not require BCC to monitor impacts to fish in its 

annual reports.

Coal mined as result of the Proposed Action would be burned at the Jim Bridger Power Plant (see 

discussion in Section 4.2.1.1.1). The emissions resulting from the combustion of the coal could have 

potential indirect effects on fish at a local and regional level due to the deposition of hazardous air 

pollutants, such as mercury, on soil and surface waters. Due to the regulation and monitoring of the power 

plant’s emissions under the existing air quality permit, and the lack of fish habitat within the analysis 

area, indirect impacts to fish as a result of coal combustion would be short-term and minor.
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4.4.2. No Action Alternative

4.4.2.1. DIRECT AND INDIRECT IMPACTS

Under the No Action Alternative, OSMRE would recommend that the ASLM disapprove the proposed 

mining plan modification and there would be no extraction of recoverable coal in the project area. As 

such, no new surface coal mining activity would be conducted under this alternative, and there would be 

no direct or indirect impacts to fish and wildlife in the mining plan modification area. However, existing 

mining activities in the adjacent Bridger Mine Complex would continue to affect fish and wildlife species 

within the fish and wildlife impact analysis area. The existing mining activities would affect wildlife and 

wildlife habitat through surface disturbance, increased noise and human activity, and through indirect 

impacts resulting from continued coal combustion at the Jim Bridger Power Plant.

4.5. Geology and Minerals 

4.5.1. Proposed Action

4.5.1.1. DIRECT AND INDIRECT IMPACTS

4.5.1.1.1. Geology

The proposed surface mining operation would remove coal and return noncoal material back into the 

mine pit on an estimated 104 acres under the Proposed Action. The geology of the mining plan 

modification area would be permanently altered. The replaced overburden material would be similar to 

pre-mining lithologies; however, the physical characteristics of the material, including permeability and 

stratigraphy, would be altered through the placement of a mixture of sizes and rock types back into the 

mined-out pit. The removal and relocation of the overburden would create a blend of the original geologic 

units. The stratigraphy of the area would also be permanently altered by the removal of the coal layer 

itself, which is currently a component of the stratigraphic arrangement of rock layers in the tract. Because 

the proposed mining plan modification area represents a small portion of the Jim Bridger coalfield, the 

Proposed Action is expected to cause a long-term, minor, direct impact to geological resources.

4.5.1.1.2. Minerals

The Proposed Action would result in the production of up to 4.5 million tons of recoverable coal over the 

life of the mine. Approximately 700,000 tons of federal coal per year would be mined from the mining 

plan modification area on average, extending the life of the mine by approximately 13 years when 

combined with future mining on adjacent private lands, from 2025 to 2037. Impact to coal reserves would 

be permanent and adverse because coal resources extracted from the mining plan modification area 

cannot be replaced, and extraction would result in a permanent depletion from the total coal reserve of the 

Jim Bridger coalfield. However, because the recoverable coal in the proposed mining plan modification 

area represents a small portion of the coal in the Jim Bridger coalfield, the Proposed Action is expected to 

cause a long-term, minor, direct impact to mineral resources.
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4.5.2. No Action Alternative

4.5.2.1. DIRECT AND INDIRECT IMPACTS

Under the No Action Alternative, OSMRE would recommend that the ASLM disapprove the proposed 

mining plan modification and there would be no extraction of recoverable coal in the project area. As 

such, no new surface coal mining activity would be conducted under this alternative, and there would be 

no direct or indirect impacts to geology and minerals in the mining plan modification area. Existing 

mining activities would continue in the adjacent Bridger Mining Complex.

4.6. Socioeconomics

4.6.1. Proposed Action

4.6.1.1. DIRECT AND INDIRECT IMPACTS

4.6.1.1.1. Population

Implementation of the Proposed Action would not affect population levels in the analysis area (estimated 

to be 44,626 in 2015; see Section 3.7.1) because no new employees would be hired. However, surface 

mining in the project area would extend the life of the mine for 13 years, which would prolong the 

duration of employment for current employees. 

4.6.1.1.2. Employment and Income

Under the Proposed Action, coal production and employment levels at the Bridger Mine Complex would 

not increase, but would be extended for an additional 13 years. Surface mining at the Bridger Mine 

Complex currently employs 230 workers (see Section 3.7.2), who would continue to be employed and 

paid during the additional 13-year time period.

Using the 1.78 coal mining employment multiplier for Wyoming’s southwest coal industry (Godby et al. 

2015), surface mining at the Bridger Mine Complex generates 409 additional jobs in the local economy 

(the industry multiplier accounts for other jobs that are created by the labor, services, and goods needed to 

operate a coal mine). The Proposed Action would also support these secondary jobs for an additional 13 

years. Other indirect effects to the local economy would continue through the purchase and use of goods 

and services needed for mine operations, vehicles, and employees.

The mining, quarrying, and oil and gas extraction sector employed the largest number of Sweetwater 

County residents (6,165 jobs) in 2014. Under the Proposed Action, this industry sector’s share of the 

workforce in Sweetwater County would not change. However, geographies with economies that focus 

narrowly on resource extraction, particularly on fossil-fuel development (such as Sweetwater County), can 

be subject to boom-and-bust cycles as well as other economic challenges, such as slower long-term 

economic growth. Due to changes in external market pressures, natural resource economies are often 

vulnerable to unpredictable cycles of economic growth and recession. This can present challenges to 

communities in the form of fluctuating tax bases, demands for public infrastructure and social services, 

employment numbers, housing prices, and migration of workers into and out of a particular area. 
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4.6.1.1.3. Housing

Existing infrastructure in Sweetwater County is sufficient to sustain the current Bridger Mine Complex 

workforce for the additional time period. The 18,735 total housing units in Sweetwater County are not 

fully occupied (87.9% occupied; see Section 3.7.3) and there are both rental and sale units on the market.

There is available housing in Rock Springs and Superior. In addition, the population growth in 

Sweetwater County over the last 5 years has been relatively slow at approximately 1.9% (see Section

3.7.1).

4.6.1.1.4. Economy

As discussed in Section 3.7.4, Wyoming’s economy has experienced a recent downturn. Approval of the 

Proposed Action would extend mining at the Bridger Mine Complex for 13 years, which would contribute 

positively to the economy through continued employment, income, and taxes and royalty payments.

Taxes and royalty payments from the mining of coal in the project area would provide direct revenue to 

the state and federal government at approximately the same rate that currently occurs because the 

Proposed Action is a continuation of mining. However, the Proposed Action would add approximately 13 

additional years to the life of the mine, which would extend the amount of time revenue is provided to the 

state and federal government.

The 2014 average price for Wyoming coal is $13.43 per ton (see Section 3.7.4). Assuming the coal mined 

from the project area would be priced similarly, the 4.5 million tons of total coal produced would be 

worth approximately $60.44 million in total revenue.

Table 4-4 shows 2014 coal production levels and percentages for Sweetwater County. 

Table 4-4. Sweetwater County Coal Production

Sweetwater County Coal Mines 2014 Coal Production 

Levels (tons)

Percent of Coal Production 

in Sweetwater County

Black Butte/Leucite Hills (surface operation) 4,017,845 42.9

Bridger Mine Complex (surface operation) 1,990,376 21.2

Bridger Mine Complex (underground operation) 3,369,731 35.9

Total 9,377,952 100

Source: Wyoming Mining Association (2016)

Based on the data shown in Table 4-4, the Bridger Mine Complex surface operation comprises 

approximately 21.2% of the coal production in Sweetwater County, which would generate approximately 

21.2% or $33,202,949 of the state assessed value for surface coal in 2014 ($156,617,682; see Section

3.7.4). This annual severance tax value would not increase under the Proposed Action because coal 

production would not increase; however, it would be paid for an additional 13 years because the life of 

the mine would be extended for 13 years. No data were found on the total ad valorem tax for coal 

production in Sweetwater County. 

The federal revenues shown in Table 3-10 would not change with the implementation of the Proposed 

Action; however, the portion of the revenues that comes from the project area would be paid for an 

additional 13 years because the life of the mine would be extended for that time period.
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Overall, the Proposed Action would have no impact on population levels and housing in the county. 

Employment, income, and the economy would be positively impacted in the short-term by the extension 

of the mine life.

4.6.2. No Action Alternative

4.6.2.1. DIRECT AND INDIRECT IMPACTS

Under the No Action Alternative, OSMRE would recommend that the ASLM disapprove the proposed 

mining plan modification and there would be no extraction of recoverable coal in the project area. 

Therefore, there would be no direct or indirect impacts to the social and economic conditions of nearby 

communities from surface mining activities in the mining plan modification area. The local population, 

employment, housing conditions, and revenue would remain similar to current conditions, because mining 

would continue in other areas of the Bridger Mine Complex. However, changes in other local industries 

could impact the socioeconomics of the communities in Sweetwater County. The extension of mine 

activities for an additional 13 years and associated employment and economic impacts would not occur 

under the No Action Alternative.

4.7. Soils

4.7.1. Proposed Action

4.7.1.1. DIRECT AND INDIRECT IMPACTS

Under the Proposed Action, 104 acres of soils (18.6% of the project area) would be directly disturbed by 

surface mining. This impact would be short term and moderate because reclamation is an ongoing process 

at the Bridger Mine Complex. The disturbance would occur in the Wint-Westvaco-Teagulf-TasselmanRogrube-Huguston-Haterton soil complex that covers 100% of the project area and analysis area. This 

soil complex has a moderate risk of soil degradation through water erosion hazard, wind erosion hazard, 

drought susceptibility, and rooting depth. More specifically, the surface mining disturbance would occur 

in the soil map units discussed in Section 3.8.2. As discussed in Section 3.8.2, the soil’s suitability as a 

plant growth medium is limited by high sand texture, pH, electrical conductivity (excess salt), sodium 

adsorption ratio (excess sodium), selenium, and calcium carbonate (BKS 2012b). Wind and water erosion 

hazard varies from negligible to severe (across the soil assessment study area) and soils are somewhat 

more susceptible to erosion from wind than water (BKS 2012b). Surface-mining activities would disturb 

soil productivity, texture, structure, and porosity through the large-scale removal, stockpiling, and 

replacement of soils during surface mining. This would be a long-term, moderate impact because of the 

physical changes to the soil and the time needed for full reclamation. Because of the soil degradation 

characteristics (water and wind erosion hazard, drought susceptibility, rooting depth, excess salt, excess 

sodium), there is an increased risk of indirect erosion impacts from surface mining. However, this risk 

would be limited by BCC’s sediment control system (discussed later in this section) and the Mine Permit 

Reclamation Plan (BCC 2009).

Soils would be removed to their full depth where surface mining takes place and all suitable soils would 

be salvaged (topsoil suitability and soil salvage depths were determined by the soil assessment using 

WDEQ-LQD guidelines for topsoil [WDEQ-LQD 1994]). When feasible and to limit impacts, the top 6 

inches of soil would be handled separately to protect topsoil. In addition, salvaged soil would be applied 

directly to regraded soils where practical. However, when field conditions preclude this opportunity or the 

amount of soil being salvaged is greater than the amount needed for application, soil would be stored in 
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stockpiles located within the permit area. Soil stockpiles would be protected from wind and water erosion 

and clearly marked with signs. Stockpiles would be located so they are out of operational pathways, 

oriented to minimize erosion, and outside of natural drainages. They would generally have slopes 

constructed at a ratio of 3 to 1 or less.

Direct haul/application of topsoil to regraded soils and storage of topsoil in stockpiles may have different 

impacts on soil components. Stockpiling has been shown to negatively impact favorable soil properties 

including microbial biomass, bulk density, water holding capacity, and viable seed populations, mainly at 

depth (Wick et al. 2008). With topsoil stripping and storage, losses of soil aggregation are thought to 

contribute to declines in soil organic matter in reclaimed systems (Ingram et al. 2005). Generally, soil 

aggregation is slow to recover and whole soil carbon is greatly reduced in all soil depths with stockpiling 

(Wick et al. 2008). Soil organic matter has been found to increase with reclamation, but there is not 

always a corresponding increase in soil macroaggregation (Wick et al. 2008). However, the results of one 

study showed that stockpiling increased stockpile surface aggregation and aggregate associated organic 

carbon concentrations after 3 years of storage (Wick et al. 2008). Another Wyoming study found that 

there were no differences in soil organic carbon or microbial biomass carbon between sites reclaimed 

with directly hauled or stockpiled topsoil at two mines where the comparison was made. However, this 

study noted that use of directly hauled topsoil may avoid or minimize some of the problems (e.g., decline 

in fungal and bacterial populations or significant losses of total whole carbon) associated with long-term 

topsoil storage (Anderson et al. 2006). Thus, chemical and biological impacts to soils would likely be 

long-term and moderate. 

As part of the mine plan, overburden materials would be sampled and characterized to ensure that any 

material that is unsuitable (toxic, acid-forming, or inhibits vegetation growth) is properly handled and 

disposed of (BCC 2009). Sampling and analysis is conducted in accordance with WDEQ-LQD guidelines 

for overburden (WDEQ-LQD 1994). Materials identified as being unsuitable would be handled by three 

procedures: 1) mixing through the mining process, 2) supplemental stripping extraction and placement, or 

3) modification of the dragline operation to place unsuitable material in the lower portions of the spoil 

where operationally feasible. Details for the three procedures can be found in the Mine Permit 

Reclamation Plan (BCC 2009). In addition, regraded spoils would be sampled before the soil is 

distributed to identify any areas of unsuitable materials within 4 feet of the surface. Any unsuitable 

materials would be covered with at least 4 feet of suitable material or relocated to the bottom of the pit 

where they would be covered by spoil from the next adjacent pit mined.

Following the completion of mining, mined areas would be backfilled and regraded, then topped with the 

stockpiled soils. This would result in reclaimed soils with different long-term physical, structural, 

biological, and chemical properties than those present prior to surface mining. Post-mining soils would 

likely be more uniform in thickness, structure, type, texture, nutrient availability, and chemistry. The 

existing soil structure would largely be eliminated by the removal and replacement of soils in areas that 

are surface mined. In addition, changes in bulk density would occur due to mixing, aeration, and 

compaction. These impacts would be long-term and moderate. Revegetation and natural weathering 

would eventually reform new soil structures with the reclaimed soils, although this would be a long-term 

process. 

Contemporaneous reclamation would normally be done to within 1,000 feet from the active pit centerline 

wherever practical. Newly applied topsoil would typically be revegetated ahead of the next growing 

season with a mixture of mostly native grasses, forbs, and shrubs. Seed mixes contain high species 

diversity. Revegetation techniques are designed to minimize erosion. In general, topsoil replacement

would occur in the spring through fall and final seeding would occur in the fall. BCC conducts a soil 

monitoring program, which tests stockpiled soil prior to application, to identify physical and chemical soil 

characteristics that are inhibitory to plant development and evaluate the suitability of soils for distribution. 
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Samples are taken from stockpiles prior to distribution and analyzed for multiple constituents, including 

pH, electrical conductivity, saturation percentage, texture, nitrate nitrogen, phosphorus, potassium, and 

boron. The data are interpreted using agronomic, soil science, and reclamation information, in 

conjunction with WDEQ-LQD guidelines. Stockpiled soils will be amended as necessary. This program 

helps to ensure revegetation success. A vegetation monitoring program would also be conducted over the 

life of the mine to aid in determining when the post-mining land use of undeveloped rangeland is met. 

Additional information on mine reclamation practices can be found in Section 2.1.1.13 and in the Mine 

Permit Reclamation Plan (BCC 2009). 

Temporary out-of-pit overburden stockpiles may be constructed on the highwall or lowwall sides of the 

pit as necessary; these stockpiles, as well as salvaged soil piles, could also directly disturb soils in the 

project area, primarily through compaction. There would be no disturbance to soils from roads because 

existing haul roads and ramps into the current pit would be used for access. Existing ramps into the pit 

would be extended as the pit progresses cut-by-cut into the project area.

Soil compaction during disturbance and/or reclamation can temporarily reduce infiltration capacity and 

result in a greater potential for runoff and erosion. In addition to the stockpile erosion control measures 

discussed above, BCC would extend its sediment control system to the surface mining activities in the 

project area. The sediment control system implements erosion control measures including:

hay or straw mulch to stabilize soils (and add a source of organic material), with alternative 

options of cover crops or soil pitting 

proper slope design (the shaping of reclaimed slopes to slopes with upper convexities, middle 

straight reaches, and lower concave reaches wherever possible) 

interceptor ditches to slow runoff, reduce erosion, and enhance sediment deposition 

temporary sediment traps when runoff flow cannot be controlled adequately with a check dam 

containment berms to direct flow into structures such as check dams or temporary sediment 

traps

revegetation of all reclaimed areas

vegetative buffer strips to prevent erosion in critical areas

drainage of disturbed areas into the pit where the water evaporates or is pumped into holding 

ponds (outside the project area) for treatment prior to discharge

design techniques using computer modeling to evaluate disturbed area runoff prior to 

disturbance and simulation of the various sediment control measures 

an alternative sediment control monitoring network (SEDCO) to monitor the effectiveness of 

sediment control 

check dams, water bars, and hay or straw bales when the SEDCO indicates a need to stabilize 

the effects of rills and gullies in reclaimed areas or in other erosion-prone areas such as 

disturbed areas

4.7.2. No Action Alternative 

4.7.2.1. DIRECT AND INDIRECT IMPACTS

Under the No Action Alternative, OSMRE would recommend that the ASLM disapprove the proposed 

mining plan modification and there would be no extraction of recoverable coal in the project area. As 

such, no new surface coal mining activity would be conducted under this alternative, and soils in the 

mining plan modification area would not be affected. 
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4.8. Topography and Physiography

4.8.1. Proposed Action

4.8.1.1. DIRECT AND INDIRECT IMPACTS

The topographical expression of the land surface in the analysis area would be permanently altered by the 

104 acres of surface disturbance. In general, the post-mining topography would be returned to its 

approximate original contour, unless a variance or exemption is granted by the WDEQ-LQD. The 

removal of the coal seam would not substantially alter the original elevation of the area following 

reclamation. This is because the topsoil and overburden that is used to backfill the pits would have 

swelled in volume after it was removed from the ground. Topsoil and overburden swells in volume after 

being removed from the ground, losing some of the compaction that has occurred over the thousands of 

years that it laid undisturbed. The increased volume of the topsoil and overburden would help compensate 

for the coal seam’s removal. Although the replaced overburden and topsoil would settle slightly over 

time, the final ground surface elevation would not be substantially different from the analysis area’s 

original elevation. Because reclamation requirements would return the proposed mining plan modification 

area to its approximate original contour, including replacement of drainages and other surface structure 

nuances, the Proposed Action is expected to have a short-term, minor, direct impact on topography and 

physiography.

4.8.2. No Action Alternative

4.8.2.1. DIRECT AND INDIRECT IMPACTS

Under the No Action Alternative, OSMRE would recommend that the ASLM disapprove the proposed 

mining plan modification and there would be no extraction of recoverable coal in the project area. As 

such, no new surface coal mining activity would be conducted under this alternative, and there would be 

no direct or indirect impacts to topography and physiography in the mining plan modification area. 

Existing mining activities at the adjacent Bridger Mining Complex would continue to affect topography 

and physiography in the existing mine permit area.

4.9. Vegetation

4.9.1. Proposed Action

4.9.1.1. DIRECT AND INDIRECT IMPACTS

Under the Proposed Action, approximately 104 acres of soil and associated vegetation (18.6% of the 

analysis area) would be directly disturbed by surface mining. The disturbance would occur in the InterMountain Basins Active and Stabilized Dune, Inter-Mountain Basins Big Sagebrush Shrubland, InterMountain Basins Mat Saltbush Shrubland, Inter-Mountain Basins Mixed Salt Desert Scrub, and Western 

Great Plains Riparian Woodland and Shrubland ecological systems. Table 4-5 presents the anticipated 

magnitude of direct impact to the ecological systems and the relative proportion of this impact compared 

to the total amount of each ecological system in the analysis area.
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Table 4-5. Anticipated Impacts on Ecological Systems in the Analysis Area

Ecological System Acres of Ecological System 

in the Analysis Area

Acres of Ecological System 

Disturbed by Proposed Action

Percent of Ecological 

System Disturbed

Inter-Mountain Basins Active and 

Stabilized Dune

11.0 2.5 22.7%

Inter-Mountain Basins Big 

Sagebrush Shrubland

374.0 61.1 16.3%

Inter-Mountain Basins Greasewood 

Flat

0.3 0 0%

Inter-Mountain Basins Mat 

Saltbush Shrubland

1.8 1.1 61.1%

Inter-Mountain Basins Mixed Salt 

Desert Scrub

128.3 18.3 14.3%

Inter-Mountain Basins Shale 

Badland

0.3 0 0%

Western Great Plains Riparian 

Woodland and Shrubland

43.7 21.1 48.3%

Total 559.4 104.1 18.6%

The ecological systems that would experience the largest acreage of disturbance would be Inter-Mountain 

Basins Big Sagebrush Shrubland, Inter-Mountain Basins Mixed Salt Desert Scrub, and Western Great 

Plains Riparian Woodland and Shrubland because the majority of the proposed disturbance is located 

within these ecological systems.

Because quantitative analyses of vegetation cover and species inventory data specifically for the project 

area were not provided in the 2012 baseline vegetation assessment, it is uncertain which of the six range 

sites (Saline Upland, Saline Lowland, Sands, Shallow Loamy, Loamy, and Saline Sub-Irrigated) mapped 

in 2012 would be affected and how many acres of each range site would be affected in the project area.

The surface disturbance and removal of vegetation increases the potential for the indirect introduction, 

establishment, and spread of noxious and/or invasive, introduced weed species, which would be an

indirect effect of the Proposed Action. However, weed control measures outlined in the Mine Permit 

Reclamation Plan (BCC 2009) would be implemented for any noticeable weed infestation of species 

listed in the Wyoming designated noxious weeds and prohibited noxious weeds list (WWPC 2015).

Following the completion of mining, mined areas would be backfilled and regraded, then topped with the 

stockpiled soils and revegetated. Contemporaneous reclamation would normally be done to within 1,000 

feet from the active pit centerline wherever practical. Newly applied topsoil would typically be 

revegetated the following spring and/or fall with a mixture of mostly native grasses, forbs, and shrubs. 

Seed mixes would be selected based on pre-mining vegetation communities, post-mining land use, seed 

availability, timing, topography, soil characteristics, and other site-specific considerations. Seed mix 

species selected for reclamation have substantial browse, livestock and/or wildlife forage, or cover value 

and are adapted to the region. Per the Mine Permit Reclamation Plan found in the approved mine 

plan/PAP/Permit, a vegetation monitoring program would also be conducted over the life of the mine to 

aid in determining when the post-mining land use of undeveloped rangeland is met (BCC 2009). 

Additional information on reclamation practices can be found in Section 2.1.1.13. Because of the 

relatively small area of surface disturbance, the acres of existing vegetation in the project area and 

surrounding area, and the reclamation and revegetation requirements that would be included in the mine 

permit, the Proposed Action is expected to have a short-term, minor impact on vegetation resources.
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4.9.2. No Action Alternative

4.9.2.1. DIRECT AND INDIRECT IMPACTS

Under the No Action Alternative, OSMRE would recommend that the ASLM disapprove the proposed 

mining plan modification and there would be no extraction of recoverable coal in the project area. As 

such, no new surface coal mining activity would be conducted under this alternative, and there would be 

no impact to vegetation resources in the mining plan modification area.

4.10. Water Resources 

4.10.1. Proposed Action

4.10.1.1. DIRECT AND INDIRECT IMPACTS

4.10.1.1.1. Surface Water

Surface Water Quantity

Mining activities have the potential to both increase surface water runoff and decrease surface water 

runoff. Increased runoff can result if mines are dewatering aquifers and discharging water into ponds or 

stream channels. Decreased runoff can result when runoff from areas upstream of a mine is captured by 

flood control reservoirs or the mine pit or routed around the active mining and reclaimed areas. Increased 

or decreased runoff would be a direct effect of the Proposed Action.

Reclamation can also increase surface water runoff. This is because topsoil is often stockpiled for long 

periods of time and lacks structure when it is applied during reclamation. Soils with diminished structure 

have lower infiltration rates in comparison to native soils, which may increase runoff until root and soil 

structure develops. The backfilling of pits during reclamation may also result in a decrease in runoff due 

to runoff being captured in areas of the backfilled pit where the use of uncompacted material has resulted 

in differential settling. 

Data from the water monitoring stations in the analysis area indicate that mining impacts to surface water 

quantity have been minimal (WDEQ-LQD 2014). However, it is reasonable to expect some amount of 

short-term reduction in water yield in the drainage due to retention in mining pits, sediment ponds, and 

alternate sediment control measures (ASCMs) in the mining plan modification area. ASCMs are used 

extensively for sediment control at the Bridger Mine Complex, and consist mostly of rock check dams.

Because of the relatively small size of the mining plan modification area and the minimal impact on water 

quantity that previous and existing mining operations in the surface water impact analysis area have had, 

the Proposed Action is expected to have a short-term, minor impact on surface water quantity. 

Surface Water Quality

Removal of vegetation and topsoil during mining activities exposes overburden and can result in 

increased erosion potential, causing an indirect effect to water quality. Runoff from areas of surface 

disturbance during mining activities may contain increased concentrations of sediments or other 

constituents which may degrade surface water quality in the analysis area. An increase in impervious 

surfaces during mining activities can also decrease infiltration and increase erosion. However, all surface 

water runoff from disturbed areas would be required to pass through a sediment pond or ASCM and meet 

specific water quality criteria prior to discharge.
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Data from water monitoring stations at the Bridger Mine Complex indicate that there is not a substantial 

difference between the sediment yields carried between undisturbed and disturbed drainages, implying 

that ASCMs are effective in reducing sediment loads from drainages disturbed by surface mining 

activities (WDEQ-LQD 2014). Data from water monitoring stations at the Bridger Mine Complex also 

indicate that TSS concentrations are highly variable and can become very high during runoff events, 

exceeding 100,000 mg/L. Water quality standards for WDEQ-WQD Class 3B waters have occasionally 

been exceeded for dissolved metals at the Bridger Mine Complex, particularly aluminum, copper, iron, 

and selenium. However, mining does not appear to be a controlling factor in the cause of the exceedances, 

because many of the exceedances were also noted upstream of the mining disturbance and during a 

baseline sampling period (WDEQ-LQD 2014). Thus, the Proposed Action is expected to have a minor 

impact on surface water quality in the short term. Following reclamation, long-term water resource 

impacts are typically increased TDS and possibly other water quality constituents. Long-term TSS are 

usually limited because of the requirements of SMCRA and stringent revegetation and BACT 

requirements after sediment ponds are removed. Given that the streamflow in the analysis area is 

primarily ephemeral, impacts to water quality would likely be short-term, minor, and limited in 

geographical extent if they were to occur.

4.10.1.1.2. Groundwater

Groundwater Quantity

During mining, sections of the alluvial aquifer in the vicinity of the Bridger Mine Complex would be 

affected by removal and replacement of alluvial sediments, drawdown due to the influences of pit dewatering, temporary diversion of streams, or increased water levels due to the infiltration of pit and pond 

discharges. In general, these direct effects would be local and would not extend large distances beyond 

the permit area. Cumulative effects to the alluvial aquifer would be mitigated by the distribution of the 

alluvial sediments only along drainages and the spatial distribution of the mines over small segments of 

the alluvial aquifer. Therefore, although there may be some direct impact to the alluvial aquifer caused by 

the Proposed Action, few to none of the impacts to the alluvial aquifer would be cumulative in nature as 

the individual mines tend to impact different sections of discrete alluvial sediments.

Predicted drawdowns by the individual mines in the overburden aquifer do not overlap with each other. In 

addition, cumulative effects of mining on the overburden would likely be limited as the sandstone units are 

discontinuous, and interbedded with claystone and siltstone. The CHIA concluded that based on current 

available data, the model predictions by the mines, and the area geology, it is expected that the impacts 

caused by mining on the overburden aquifer would likely be short-term and minor (WDEQ-LQD 2014).

Although mining would have impacts within the permit boundary, based on available data, information 

presented in the mine permit, and analysis in the CHIA, the potential for material damage outside the 

permit boundaries to groundwater quantity is limited (WDEQ-LQD 2014). In locations where the mined 

coal seams are in the Almond Formation, the Ericson Sandstone aquifer is separated from the coal seams 

by a thick, low permeable interbedded sandstone, claystone, and siltstone Almond Formation underburden 

unit (WDEQ-LQD 2014). Therefore, the groundwater quantity impacts on the Ericson Sandstone aquifer 

would be minimal with no discernible effects that can be attributed to mining (WDEQ-LQD 2014).

Predicted drawdowns by the individual mines in the coal seams do not overlap with each other. Therefore, 

the cumulative effects of mining on the coals seams would likely be limited as these seams are generally 

less than 20 to 30 feet thick. The CHIA concluded that based on current available data, the model 

predictions by the mines, and the area geology, it is expected that the impacts caused by mining on the 

overburden aquifer would likely be short-term and minor (WDEQ-LQD 2014).
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Predicted drawdowns by the individual mines in the underburden aquifer do not overlap with each other. 

The relatively lower hydraulic conductivity and the discontinuous nature of the underburden supports that 

the Proposed Action would have limited cumulative effects on the underburden groundwater system.

Given that the Ericson Formation is up to 700 feet thick, the Proposed Action is expected to have a shortterm, minor impact on groundwater quantity as a result of drawdown, and would not affect the ability of 

the existing Ericson wells outside the mine permit boundaries to supply their intended use.

Groundwater Quality

Groundwater flowing through the backfill aquifer may have higher concentrations of dissolved 

constituents because more fresh mineral surfaces are exposed for chemical reaction in the backfill than in 

the undisturbed sediments. Initial conditions in the backfill include a more oxidized environment when 

compared to the undisturbed conditions. This increase in exposed mineral surfaces and difference in 

oxidation state may cause an increase in TDS and other constituents in groundwater. There is a potential 

for groundwater migrating from the backfill aquifer to affect the undisturbed native aquifers outside mine 

permit boundaries.

The Bridger Mine Complex mining permit provides a detailed description of how overburden materials 

are sampled, characterized, handled, and identified as suitable or unsuitable. The permit also documents 

how unsuitable materials would be mitigated in the backfilling process, such as blending unsuitable 

overburden with suitable material, using suitable material from adjacent spoil areas, and selective 

placement of material in between the predicted post-mine potentiometric surface and 4 feet below the 

graded backfill surface. 

As part of the Bridger Mine Complex’s annual reports, which are evaluated by WDEQ-LQD, backfill 

material sampling data are reviewed to ensure that the operator has properly handled and disposed of all 

overburden and spoil material that may be toxic or acid-forming. This review provides some assurance that 

the water quality of the backfill aquifer would be able to support the post-mining land use. Given the 

detailed process for handing and sampling overburden materials, the Proposed Action is expected to have a 

short-term, minor, direct impact on groundwater quality. Although mining would have impacts within the 

permit boundary, based on available data, information presented in the mine permit, and analysis in the 

CHIA, the potential for material damage outside the permit boundaries to groundwater quality is limited 

(WDEQ-LQD 2014). In locations where the mined coal seams are in the Almond Formation, the Ericson 

Sandstone aquifer is separated from the coal seams by a thick, low permeable interbedded sandstone, 

claystone, and siltstone Almond Formation underburden unit (WDEQ-LQD 2014). Therefore, the 

groundwater quality impacts on the Ericson Sandstone aquifer would be minimal with no discernible effects 

that can be attributed to mining (WDEQ-LQD 2014). The proposed mining activities are not expected to 

change the potential for material damage to groundwater quality in any of the aquifers of concern.

4.10.2. No Action Alternative

4.10.2.1. DIRECT AND INDIRECT IMPACTS

Under the No Action Alternative, OSMRE would recommend that the ASLM disapprove the proposed 

mining plan modification and there would be no extraction of recoverable coal in the project area. As 

such, no new surface coal mining activity would be conducted in the mining plan modification area under 

this alternative, and there would be no direct or indirect impacts to surface water and groundwater 

resources in the mining plan modification area. Existing mining activities at the adjacent Bridger Mining 

Complex would continue to affect surface water and groundwater resources in the surface water and 

groundwater impact analysis areas.
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4.11. Wetlands and Riparian Zones

4.11.1. Proposed Action

4.11.1.1. DIRECT AND INDIRECT IMPACTS

4.11.1.1.1. Wetlands

Under the Proposed Action, there would be no direct or indirect impacts to wetlands from the proposed 

surface mining activities because there are no NWI wetlands identified in the wetlands and riparian zones 

impact analysis area.

4.11.1.1.2. Riparian Zones

Under the Proposed Action, mining activities would cause 21.1 acres of surface disturbance in Western 

Great Plains Riparian Woodland and Shrubland land cover type. This represents approximately 48% of 

the total amount of this land cover type in the wetlands and riparian zone impact analysis area. Areas 

disturbed by mining activities would be returned to their approximate original contour during reclamation. 

These acres of disturbance would be revegetated with seed mixes selected based on pre-mining vegetation 

communities, post-mining land use, seed availability, timing, topography, soil characteristics, and other 

site-specific considerations. Seed mix species selected for reclamation have substantial browse, livestock 

and/or wildlife forage, or cover value and are adapted to the region. The direct impact to riparian zones 

would be short-term and minor. The proposed mining activities would disturb almost half of the Western 

Great Plains Riparian Woodland and Shrubland land cover type in the analysis area, but the required 

reclamation and revegetation activities would return the disturbed areas to their approximate original 

contour and pre-mining vegetation types.

4.11.2. No Action Alternative

4.11.2.1. DIRECT AND INDIRECT IMPACTS

Under the No Action Alternative, OSMRE would recommend that the ASLM disapprove the proposed 

mining plan modification and there would be no extraction of recoverable coal in the project area. As 

such, no new surface coal mining activity would be conducted under this alternative, and there would be 

no direct or indirect impacts to wetlands and riparian zones in the mining plan modification area.

5. CUMULATIVE IMPACTS ANALYSIS

As defined in 40 CFR 1508.7 (CEQ regulations for implementing NEPA), a cumulative impact is an 

impact on the environment that results from the incremental impact of the action when added to other 

past, present, and reasonably foreseeable future actions (RFFAs), regardless of which agency (federal or 

non-federal) or person undertakes such actions. Cumulative impacts may result from individually minor 

but collectively significant actions occurring over a period of time.

5.1. Analysis Areas

The geographic extent of cumulative impacts may vary by the type of resource and resource issues and by 

the type of potential impact. The time frames, or temporal boundaries, for those impacts may also vary by 

resource and resource issue. Spatial and temporal cumulative impact analysis areas (CIAAs) have been 

developed for each resource and are listed in Table 5-1. The temporal boundary for each resource was 

chosen because it is a reasonable time frame within which to predict RFFAs.
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Table 5-1. Cumulative Impacts Analysis Areas by Resource

Resource CIAA Rationale Total CIAA 

Acreage

Temporal 

Boundary 

Air Quality Sweetwater County This CIAA was chosen because it is a typical 

spatial boundary used to determine compliance 

with NAAQS.

6,672,640 Life of the mine

Cultural and 

Historic 

Resources

Lower Deadman Wash 

HUC 12 watershed

Much of human cultural and behavioral variation 

is conditioned by the natural environment. 

Accordingly, archaeological, historical, and 

cultural sites within a defined natural habitat are 

often the product of a singular settlement 

system. 

This CIAA was chosen because it is a defined 

natural habitat, and impacts to cultural 

resources in one part of that habitat can affect a 

broader understanding of the interrelationships 

between sites in the habitat area as a whole.

33,990 Effects on 

cultural 

resources could 

be permanent.

Fish and Wildlife Lower Deadman Wash 

HUC 12 watershed

The watershed provides a rational topographical 

boundary to analyze the cumulative impacts to 

fish and wildlife.

33,990 Life of the mine

and reclamation

Geology and 

Minerals

Bridger Mine Complex 

Cumulative 

Hydrological 

Assessment Area for 

groundwater analysis

The Cumulative Hydrological Assessment Area 

was used to analyze the cumulative impacts 

during the permitting process. Thus, using this 

boundary makes this analysis consistent with 

the permitting analysis.

673,297 Effects on 

geology and 

minerals would 

be permanent.

Socioeconomics Sweetwater County This CIAA was chosen because the economic 

and demographic effects of the mine and 

surrounding mines would likely be experienced 

by communities in the county.

6,672,640 Life of the mine

Soils Bridger Mine Complex 

Cumulative 

Hydrological 

Assessment Area for 

groundwater analysis

The Cumulative Hydrological Assessment Area 

was used to analyze cumulative impacts during 

the permitting process. Use of this boundary 

provides consistency with the permitting 

analysis.

673,297 Life of the mine 

and reclamation

Topography and 

Physiography

Bridger Mine Complex The Bridger Mine Complex boundary is a 

rational boundary for analysis of impacts to 

topography and physiography as a result of 

mining activities because impacts would be 

limited to the surface disturbance caused by 

mining.

32,841 Effects on 

topography and 

physiography 

would be 

permanent.

Vegetation Bridger Mine Complex 

Cumulative 

Hydrological 

Assessment Area for 

groundwater analysis

The Cumulative Hydrological Assessment Area 

was used to analyze cumulative impacts during 

the permitting process. Use of this boundary 

provides consistency with the permitting 

analysis.

673,297 Life of the mine 

and reclamation

Water 

Resources

Bridger Mine Complex 

Cumulative 

Hydrological 

Assessment Areas for 

surface water and 

groundwater analysis

The Cumulative Hydrological Assessment Area 

was used to analyze the cumulative impacts on 

water resources during the permitting process. 

Thus, using this boundary makes this analysis 

consistent with the permitting analysis.

Surface 

water: 33,990

Groundwater: 

673,297

Life of the mine 

and reclamation

Wetlands and 

Riparian Zones

Lower Deadman Wash 

HUC 12 watershed

The watershed provides a rational topographical 

boundary to analyze the cumulative impacts to 

wetlands and riparian zones.

33,990 Life of the mine 

and reclamation

Note: Because the direct and indirect effects analysis for climate change in Chapters 3 and 4 addresses cumulative impacts from the Proposed Action, 

a separate cumulative effects analysis for climate change is not needed, according to new CEQ guidance (CEQ 2016). 
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5.2. Past, Present, and Reasonably Foreseeable Future 

Actions

5.2.1. Past and Present Actions Summary

Past and present actions in the CIAAs that would affect the resources analyzed in this EA include cattle 

and sheep grazing; exploratory drilling for coal in support of the Bridger Mine Complex and other coal 

mining in the area; coal mining at the Bridger Mine Complex, Black Butte Mine, and Leucite Hills Mine 

(currently undergoing reclamation); roads; operation of the Jim Bridger Power Plant; and oil and gas 

exploration and development activity. The permit areas for the Bridger Mine Complex, Black Butte Mine, 

and Leucite Hills Mine cover approximately 50,405 acres in Sweetwater County and the hydrological 

assessment area for groundwater analysis. The permit areas for the Bridger Mine Complex and the 

Leucite Hills Mine cover approximately 1,134 acres of the Lower Deadman Wash HUC 12 watershed.

Surface disturbance approved at the three mines through 2014 totals 32,462 acres (WDEQ-LQD 2014). 

Past and present long-term disturbance from oil and gas development is estimated to be 5,069 acres on all 

lands within the BLM Rock Springs Field Office Planning Area (BLM 2013a).

5.2.2. Reasonably Foreseeable Future Actions Summary

RFFAs are decisions, funding, or formal proposals that are either existing or are highly probable, based 

on known opportunities or trends. The following RFFAs have been identified: continuing operation of the 

Bridger Mine Complex, expansion of the Black Butte Mine, oil and gas development, and the Gateway 

West transmission line project.

Mining operations at the Bridger Mine Complex are expected to continue through at least 2037 for 

surface production and 2024 for underground mining.

The Black Butte Mine is currently applying for a 449-acre lease modification to its existing federal coal 

lease for its surface coal mine. Black Butte Mine would also need to initiate modifications to its current 

mine permit area to allow for future mining.

Future long-term oil and gas surface disturbance is projected to be 12,571 acres on all lands within the 

BLM Rock Springs Field Office Planning Area (BLM 2013a).

The Gateway West transmission line project would build and operate approximately 1,000 miles of new 

high-voltage transmission lines between Glenrock, Wyoming, and Melba, Idaho, including approximately 

150 miles of 230-kilovolt (kV) lines in Wyoming and approximately 850 miles of 500-kV lines in 

Wyoming and Idaho. The BLM-authorized route from the Wamsutter area to Anticline/Jim Bridger 

(Segment 3) would run east to west in a transmission corridor generally following Interstate 80 and an 

existing utility corridor. The route includes Segment 3A, a new 345-kV line between the Anticline 

substation and the Jim Bridger Power Plant (Idaho Power and Rocky Mountain Power 2015).

The BLM Rock Springs Field Office Planning Area’s Reasonable Foreseeable Development Scenario

estimates up to 6,018 oil and gas wells to be developed in the planning area (BLM 2016). BLM estimates 

each well to represent approximately 7.1 acres of surface disturbance. Thus, these wells would result in 

approximately 42,727 acres of surface disturbance within the 3.6 million-acre planning area, or 1.2% of 

the planning area. Because the exact location of these wells is not known, the cumulative effects analysis 

assumes that the disturbance will be evenly distributed across the planning area and that approximately 

1.2% of each CIAA would be affected by reasonably foreseeable oil and gas well disturbance.
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5.2.3. Cumulative Impacts by Resource Issue Category 

Cumulative impacts organized by resource issue category are described below. A choice of No Action 

would not contribute incrementally to the impacts of past, present, and reasonably foreseeable future 

actions, because under the No Action Alternative, OSMRE would recommend that the ASLM disapprove 

the proposed mining plan modification and there would be no extraction of recoverable coal in the project 

area. As a result, a No Action Alternative cumulative impacts analysis is not included below.

5.2.3.1. AIR QUALITY

Past and present actions in the air quality CIAA are described in Section 5.2.1. Most past and present 

action emissions (that are still occurring) likely consist of fugitive dust and emissions associated with 

mining activities, the Jim Bridger Power Plant, and oil and gas wells. Emissions from the Jim Bridger 

Power Plant are summarized in Table 3-6. Present emissions in the air quality CIAA are reflected in the 

ambient air quality data shown in Table 3.3, which is in compliance with the NAAQS and WAAQS. 

RFFAs in the air quality CIAAs are described in Section 5.2.2. In addition, the WDEQ-AQD lists the 

following new source review permit applications (WDEQ-AQD 2016b):

Jim Bridger Power Plant has requested a renewal of plant-wide applicability limitations for NOx

and SO2 at their current levels. WDEQ-AQD has indicated it will consider retaining the existing 

limitations as appropriate for the facility. This will not result in an emission change.

Wexpro Company submitted an application to modify an existing gas pad through the addition of 

a compressor engine. The engine would add the following emissions to the CIAA: 5.1 tons per 

year of NOX, 14.7 tons per year of CO, 5.1 tons per year of VOC, and 0.37 tons per year of 

formaldehyde. 

QEPM Gathering I, LLC submitted an application to modify a compressor station through the 

replacement of an old compressor engine with a new compressor engine. The new engine would 

reduce emissions of NOx, CO, VOC, and formaldehyde. WDEQ-AQD indicated in the 

application analysis that the change would have a negligible impact on existing ambient air 

quality. 

Mountain Gas Resources LLC submitted an application to modify a compressor station through 

the replacement of an old compressor engine with a new compressor engine. The new engine 

would increase existing CO emissions by 4.0 tons per year and existing formaldehyde emissions 

by 0.11 tons per year; it would decrease NOx and VOC emissions. WDEQ-AQD indicated in the 

application analysis that ambient air quality standards would be maintained with the approval of 

this application (through the use of control measures). 

Of the four RFFAs listed above, changes requested by Wexpro Company and Mountain Gas Resources 

LLC have the possibility to increase emissions in the air quality CIAA, but in low quantities that are 

unlikely to impact NAAQS attainment. Expansion of the Black Butte Mine and oil and gas development 

also has the potential to create new emissions in the CIAA. However, the Environmental Assessment for 

Black Butte Coal Company Lease Modification to WYW-6266 concluded that the proposed Black Butte 

Mine expansion would result in emissions that are similar to current conditions respective to public health 

protection, and the extremely rural setting would make air resources impacts negligible (BLM 2017). 

Regarding oil and gas development, gas, oil, and coalbed natural production are expected to increase 

through 2031, with an increase in associated emissions and cumulative impacts. From 2012–2031, 

cumulative production of conventional gas in the BLM Rock Springs Field Office Planning Area is 

expected to be between 1,631,711,137 thousand cubic feet and 4,096,453,750 thousand cubic feet; 

cumulative production of conventional oil is expected to be between 39,662,119 barrels and 99,572,794 

barrels; and cumulative production of coalbed natural gas is expected to range from 5,529,685 thousand 
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cubic feet to 8,385,492 thousand cubic feet (BLM 2013b). The range in values is based on different 

alternatives being analyzed for the revised resource management plan. No data were identified for 

expected emissions associated with these production increases. The Proposed Action would not increase 

annual emissions currently occurring from the Bridger Mine Complex because it is a continuation of 

existing mining (there would be no change in annual production); rather, it would extend operations at 

current production and emission levels for 13 years. Because the Proposed Action would allow the mine 

to operate and emit air pollutants for a longer period of time, it would add cumulatively to air emissions in 

the CIAA during these years. However, the proportion of those emissions (see Table 3-4) that would 

come directly from the mining of Sections 12 and 24 is unknown. Direct emissions of air pollutants from 

mining in the project area would be limited by current WDEQ-AQD air quality permits for the Bridger 

Mine Complex (Air Quality Permits MD-9156 and MD-12225); indirect emissions from the burning of 

coal mined from the project area would be limited by the Jim Bridger Power Plant’s operating permit and 

air quality permit with WDEQ-AQD. It is not expected that the terms of any of these air quality permits 

would be violated as a result of the Proposed Action. The discussion provided in section 4.2.1.1.2

includes direct and indirect effects analyses for GHG emissions. Due to the global nature of climate 

change, and the difficulty therefore of predicting climate change impacts caused by an incremental 

increase in GHG emissions from specific actions separately or together, a separate cumulative impacts 

analysis for GHG emissions is not appropriate.

5.2.3.2. CULTURAL RESOURCES

Cultural resources tend to degrade over time from natural forces; however, many survive for hundreds or 

thousands of years. Any land-disturbing activity can disturb or damage cultural resources. Impacts to 

cultural resources in the CIAA would primarily result from past, present, and reasonably foreseeable 

future actions associated with surface and subsurface disturbance. Impacts would depend on the amount, 

placement, and type of disturbance, and could be beneficial (if the identification of cultural resources 

newly identified during surface disturbance contributes cumulatively to an increase in the knowledge of 

cultural properties in the area) or adverse (if widespread disturbance activities cover a large portion of the 

landscape when viewed as a whole and lead to an increase in the potential for destruction or damage of 

cultural resources).

Based on site-specific cultural resource inventories (see Section 3.4.2), the Proposed Action would not 

impact any cultural resources eligible for the NRHP. Therefore, the Proposed Action would not contribute 

to cumulative impacts in the cultural resources CIAA.

5.2.3.3. FISH AND WILDLIFE

The CIAA for fish and wildlife is the Lower Deadman Wash HUC 12 watershed. There are 481 acres of

land in the fish and wildlife CIAA that are identified as developed land. The permit areas for the Bridger 

Mine Complex and Leucite Hills Mine cover approximately 1,134 acres of land in the fish and wildlife 

CIAA. The reasonably foreseeable surface disturbance from oil and gas development in the fish and 

wildlife CIAA is approximately 408 acres. The Proposed Action would add 104 acres of surface 

disturbance to the approximately 2,023 acres of surface disturbance caused by past, present, and 

reasonably foreseeable future actions in the fish and wildlife CIAA. The Proposed Action would represent 

an approximate 5.1% increase in disturbance to suitable wildlife habitat in the fish and wildlife CIAA. All 

mining and oil and gas operations are required to reclaim the land to its approximate original contour and 

pre-development uses, which would include revegetating the land with appropriate seed mixes. 

Revegetation activities would help restore disturbed areas so that it could be used as wildlife habitat, if the 

areas were used as wildlife habitat prior to mining activities. 
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The Table 5-2 lists the acres of big-game habitat affected by the Proposed Action and the percentage of 

available habitat in the CIAA that the affected acres represent. The acres of big-game habitat that are 

affected by the Proposed Action would be reclaimed following disturbance.

Table 5-2. Big-Game Habitat Acres Affected by the Proposed Action and Percentage of Available Acres

in the CIAA

Habitat Type Acres Affected by Proposed Action 

(% of available acres in CIAA)

Pronghorn antelope crucial, winter/year-long 77.6 (0.4%)

Pronghorn antelope winter/year-long 26.5 (0.2%)

Elk year-long 104.1 (0.5%)

Mule deer winter/year-long 104.1 (0.3%)

The hazardous air pollutants, such as mercury, released into the atmosphere by the combustion of coal 

from the project area at the Jim Bridger Power Plant could be deposited and accumulate in the 

hydrological systems in the CIAA for fish and wildlife. This would add cumulatively to other sources of 

HAPs in the CIAA’s hydrological systems and create potential short-term, negligible cumulative impacts 

to threatened and endangered Colorado River fish. The nature of these impacts is described in Section 

4.4.1.1.4.

5.2.3.4. GEOLOGY AND MINERALS

Under the Proposed Action, the proposed mining activities would add 104 acres of disturbance to the 

surface geology in the geology and minerals CIAA. Impacts to geology and minerals from past, present, 

and reasonably foreseeable future actions are similar in nature to the impacts from the Proposed Action, 

as many of these actions involve surface disturbance from mining activities, as well as oil and gas 

development activities. The permit areas for the Bridger Mine Complex, Black Butte Mine, and Leucite 

Hills Mine cover approximately 50,405 acres of the geology and minerals CIAA. There are also 

approximately 2,621 acres of land in the geology and minerals CIAA that are identified as developed 

land. The reasonably foreseeable surface disturbance from oil and gas development in the geology and 

minerals CIAA is approximately 8,080 acres. The total acres of past, present, and reasonably foreseeable 

future actions causing surface disturbance in the geology and minerals CIAA is approximately 61,106 

acres. The Proposed Action would represent a less than 0.2% cumulative increase in the total geological 

disturbance from past, present, and reasonably foreseeable future actions in the CIAA (61,106 acres).

5.2.3.5. SOCIOECONOMICS

Cumulative impacts to socioeconomics may be beneficial or adverse. Potential cumulative impacts from 

past, present, and reasonably foreseeable future actions in the socioeconomics CIAA include changes in 

population and employment, housing demands, effects on the local economy through the purchase and 

use of goods and services, and demands on government services, school districts, and local infrastructure.

Past and present actions in the socioeconomics CIAA are described in Section 5.2.1. RFFAs within the 

CIAA, including proposed mining, oil and gas development, and the Gateway West transmission line 

project, would add cumulatively to the economic output of the county.

The Proposed Action would add cumulatively to the coal mining jobs created by past, present, and 

reasonably foreseeable future actions. Approval of the Proposed Action would allow the Bridger Mine 

Complex to continue employment at the surface mine for approximately 230 workers for an additional 13 
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years, and would continue generating related secondary employment in the local economy (409 additional 

jobs; see Section 4.6.1.1.2). In addition, revenue generation and economic contributions from taxes and 

royalties on the mined coal would be extended for an additional 13 years.

5.2.3.6. SOILS

Land-disturbing activities that remove native vegetation and topsoil from the CIAA may cumulatively

and incrementally affect soil resources. Cumulative impacts from the disturbances would depend on the 

amount, placement, and type of surface disturbance; the type (complex) of soil; and soil characteristics. 

Specific impacts to soils include removal of vegetation, exposure of soil, mixing of soil horizons (layers), 

soil compaction, loss of productivity, and increased susceptibility to erosion. The permit areas for the 

Bridger Mine Complex, Black Butte Mine, and Leucite Hills Mine cover approximately 50,405 acres of 

the soils CIAA. The reasonably foreseeable surface disturbance from oil and gas development in the soils

CIAA is approximately 8,080 acres. 

Land cover types indicate impacts to soils through erosion, compaction, and topsoil degradation. In the 

soils CIAA, there are 483 acres of Pasture/Hay land cover type, 17 acres of Developed, High Intensity 

land cover type, 260 acres of Developed, Medium Intensity, 646 acres of Developed, Low Intensity land 

cover type, and 1,215 acres of Developed, Open Space. These agriculture and developed land cover types 

in the soils CIAA total 2,621 acres. When added to the known and reasonably foreseeable mine surface 

disturbance of approximately 50,405 acres, as well as the approximately 8,080 acres of reasonably 

foreseeable oil and gas development, there are approximately 61,106 acres of past, present, and 

reasonably foreseeable future actions causing surface disturbance in the soils CIAA. Surface disturbance 

to soils under the Proposed Action would comprise 104 acres or 0.02% of the soils CIAA. This 

constitutes a less than 0.2% addition to the past, present, and reasonably foreseeable future total surface 

disturbance (61,106 acres). Reclamation of disturbed areas would limit cumulative impacts to soils.

5.2.3.7. TOPOGRAPHY AND PHYSIOGRAPHY

Under the Proposed Action, the proposed mining activities would add 104 acres of disturbance in the 

32,841-acre topography and physiography CIAA. Approximately 11,726 acres of land are expected to be 

disturbed and reclaimed over the life of the Bridger Mine Complex. Impacts to topography and 

physiography from the Proposed Action would be similar in nature to the impacts from past, present, and 

future mining activities in the Bridger Mine Complex. All mining operations are required to reclaim the 

mined land to its approximate original contour, but there are still some permanent changes to topography 

as a result of the mining and reclamation activities. The Proposed Action would add cumulatively to the 

impacts from past, present, and future mining activities in the Bridger Mine Complex, representing an 

approximate 0.9% increase to the total disturbance in the CIAA.

5.2.3.8. VEGETATION

The removal of native vegetation and topsoil through surface disturbance may cumulatively and 

incrementally affect vegetation communities by fragmentation and increased competition with noxious 

and invasive weeds. In addition, surface disturbance may cause soil compaction, increased erosion, and 

fugitive dust that can cumulatively impact vegetation through decreases in plant productivity and species 

composition. 

As with the soils CIAA, there are approximately 2,621 acres of agriculture and developed land cover 

types in the vegetation CIAA. The permit areas for the Bridger Mine Complex, Black Butte Mine, and 

Leucite Hills Mine cover approximately 50,405 acres of the vegetation CIAA. The reasonably foreseeable 

surface disturbance from oil and gas development in the vegetation CIAA is approximately 8,080 acres. 
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There are approximately 61,106 acres of past, present, and reasonably foreseeable future disturbance in 

the vegetation CIAA. Surface disturbance to vegetation under the Proposed Action would comprise 

approximately 104 acres or 0.02% of the vegetation CIAA. This constitutes a less than 0.2% addition to 

the past, present, and reasonably foreseeable future total surface disturbance (61,106 acres). Reclamation 

and revegetation of disturbed areas with native seed or other appropriate species would limit the 

cumulative impacts to vegetation.

5.2.3.9. WATER RESOURCES 

5.2.3.9.1. Surface Water

The CIAA for surface water is the Lower Deadman Wash HUC 12 watershed. There are 481 acres of land 

in the surface water CIAA that are identified as developed land. The permit areas for the Bridger Mine 

Complex and Leucite Hills Mine cover approximately 1,134 acres of land in the surface water CIAA. The 

reasonably foreseeable surface disturbance from oil and gas development in the fish and wildlife CIAA is 

approximately 408 acres. The Proposed Action would add cumulatively to the approximately 2,023 acres 

of surface disturbance resulting from past, present, and reasonably foreseeable future actions in the 

surface water CIAA. The 104 acres of surface disturbance under the Proposed Action would represent a 

5.1% increase in total surface disturbance in the surface water CIAA. As discussed in Section 4.10.1.1.1, 

the Proposed Action is expected to have minimal impacts on surface water quantity and quality. 

According to the CHIA, impacts to surface water quantity and quality from past and present mining 

activities in the surface water CIAA have been minimal (WDEQ-LQD 2014). The Proposed Action’s 

cumulative impacts on surface water quantity and quality, when added to the impacts from past, present, 

and reasonably foreseeable future actions, are also expected to be minor. 

5.2.3.9.2. Groundwater

There are approximately 2,621 acres of land in the groundwater CIAA that are identified as developed 

land. The permit areas for the Bridger Mine Complex, Black Butte Mine, and Leucite Hills Mine cover 

approximately 50,405 acres of the groundwater CIAA. The reasonably foreseeable surface disturbance 

from oil and gas development in the groundwater CIAA is approximately 8,080 acres. The total acres of 

past, present, and reasonably foreseeable future actions causing surface disturbance in the groundwater 

CIAA is approximately 61,106 acres. The Proposed Action would represent a less than 0.2% cumulative 

increase in the total surface disturbance from past, present, and reasonably foreseeable future actions in 

the groundwater CIAA (61,106 acres). As discussed in Section 4.10.1.1.2, the Proposed Action is 

expected to have minimal impacts on groundwater quantity and quality. According to the CHIA, impacts 

to groundwater quantity and quality from past and present mining activities in the groundwater CIAA 

have also been minimal (WDEQ-LQD 2014). The Proposed Action’s cumulative impacts on groundwater 

quantity and quality, when added to the impacts from past, present, and reasonably foreseeable future 

actions, are also expected to be minor. 

5.2.3.10. WETLANDS AND RIPARIAN ZONES

5.2.3.10.1. Wetlands

Under the Proposed Action, no NWI wetlands would be affected by the proposed mining activities. Thus, 

there would be no cumulative impacts to wetlands as a result of the Proposed Action. 
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5.2.3.10.2. Riparian Zones

Under the Proposed Action, mining activities would cause 21.1 acres of surface disturbance in Western 

Great Plains Riparian Woodland and Shrubland land cover type. This represents approximately 2.0% of 

the total amount of this land cover type in the wetlands and riparian zone CIAA. This would add 

cumulatively to the riparian areas disturbed by past, present, and reasonably foreseeable future actions in 

the wetlands and riparian zones CIAA. Areas disturbed by mining activities under the Proposed Action 

would be returned to their approximate original contour during reclamation. The acres of disturbance 

caused by the Proposed Action would be revegetated with seed mixes selected based on pre-mining 

vegetation communities, post-mining land use, seed availability, timing, topography, soil characteristics, 

and other site-specific considerations. Seed-mix species selected for reclamation have substantial browse, 

livestock and/or wildlife forage, or cover value and are adapted to the region.

6. MITIGATION MEASURES 

Mitigation includes specific means, measures, or practices that would reduce or eliminate the effects of 

the Proposed Action. Mitigation measures can be applied to reduce or minimize adverse effects to 

biological, physical, or socioeconomic resources. No mitigation measures have been identified for the 

Proposed Action, based on the project design features identified in Section 2.1.1.15 (design features are 

specific means, measures, or practices such as standard operating procedures, stipulations, and best 

management practices that make up the Proposed Action). 

7. CONSULTATION AND COORDINATION

7.1. Summary of Public Participation 

As required under NEPA, OSMRE solicited public comments on the Proposed Action. The public 

scoping period began on June 1, 2016, and finished on July 1, 2016. OSMRE published a public notice in 

the Rock Springs Rocket-Miner newspaper, published a public notice on OSMRE’s electronic bulletin 

board, and sent out a public scoping letter and requested comments within the 30-day public comment 

period. The mailing list can be found in the administrative record. Public scoping letters were sent to 140 

recipients, including government entities, private companies, and landowners. Nine comment letters were 

received.

This EA is available on the OSMRE webpage at 

http://www.wrcc.osmre.gov/initiatives/BridgerMineWY2727.shtm. 

7.2. Persons, Groups, and Agencies Consulted 

OSMRE initiated consultation regarding the Proposed Action in June 2016 with the following tribes: 

Shoshone-Bannock Tribes 

Eastern Shoshone Tribe

Northern Arapahoe Tribe

Ute Indian Tribe
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Tribes are offered an opportunity to identify cultural or religious concerns, or Traditional Cultural 

Properties through direct government-to-government consultation with OSMRE. No cultural or religious 

concerns or Traditional Cultural Properties have been identified through consultation with the tribes. 

7.3. List of Preparers 

Tables 7-1 and 7-2 identify OSMRE and consultant staff used in the preparation of this EA. 

Table 7-1. OSMRE Staff used to Prepare this Environmental Assessment

Name Agency Position/Project Responsibility

Marcelo Calle OSMRE Division Manager

Logan Sholar OSMRE Natural Resource Specialist

Lauren Mitchell OSMRE Environmental Protection Specialist

Gretchen Pinkham OSMRE Air Quality/Climate Change

Karen Jass OSMRE Geology/Physiology/Topography

Jeremy Illiff OSMRE Cultural/Paleontological

Flynn Dickinson OSMRE Water Resources

Jacob Mulinix OSMRE Soil Resources

Table 7-2. SWCA Environmental Consultants Staff used to prepare this Environmental Assessment

Name Position Role

Jeremy Eyre, J.D. NEPA writer Geology/minerals, fish and wildlife, water 

resources, wetlands/riparian areas, topo

Gretchen Semerad, M.S. NEPA writer Air, cultural resources, soils, socioeconomics

Audrey McCulley, B.S. NEPA writer Vegetation

David Steed Project manager NEPA review

Rachel Johnson, B.S. GIS specialist All maps and GIS data

Danielle Desruisseaux, B.A. Technical editor Technical editing

Debbi Smith Formatter Formatting
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Wick, A.F., P.D. Stahl, L.J. Ingram, and L. Vicklund. 2008. Soil Aggregate and Aggregate Associated 

Carbon Recovery in Short-Term Stockpiles. Paper presented at the 2008 National Meeting of the 

American Society of Mining and Reclamation, Richmond, Virginia, “New Opportunities to 

Apply Our Science” June 14-19, 2008. Available at: 

http://www.asmr.us/Portals/0/Documents/Conference-Proceedings/2008/1389-Wick.pdf. 

Accessed October 24, 2016. 

Wyoming Department of Environmental Quality (WDEQ). 2015. Wyoming Air Quality Monitoring 

Network. Ambient Standards. Available at: 

http://www.wyvisnet.com/AmbientStandards/Default.aspx. Accessed August 24, 2016.

Wyoming Department of Environmental Quality, Air Quality Division (WDEQ-AQD). 2005. Operating 

Permit PacifiCorp Jim Bridger Plant. Available at: http://deq.wyoming.gov/aqd/title-voperating-permit-program/resources/final-permits/. Accessed on August 25, 2016.

———. 2012. Ozone Nonattainment Boundary. Available at: http://sgirt.webfactional.com/filesearch/

content/Air%20Quality%20Division/Programs/Ozone/Winter%20Ozone-Nonattainment

%20Information/2012_AQD_UGRB-Ozone-Nonattainment-Area-Map.pdf. Accessed August 

24, 2016.

———. 2016a. Wyoming Ambient Air Monitoring Annual Network Plan 2016. Available at: http://deq.

wyoming.gov/aqd/monitoring/resources/annual-network-plans/. Accessed August 24, 2016.

———. 2016b. New Source Review. Applications on Notice. Sweetwater County. Available at: 

http://deq.wyoming.gov/aqd/new-source-review/resources/applications-on-notice/. Accessed 

December 1, 2016.
Jim Bridger Coal Mine Complex Mining Plan Modification for Federal Coal Lease WYW02727 

Environmental Assessment

112

Wyoming Department of Environmental Quality, Land Quality Division (WDEQ-LQD). 1994. Both Coal 

and Non-coal Operations. Guideline No. 1 - Topsoil and Overburden. Available at: 

http://deq.wyoming.gov/lqd/resources/guidelines/. Accessed October 24, 2016.

———. 2014. Cumulative Hydrologic Impact Assessment of Coal Mining in the Greater Green River 

Basin, Southwestern Wyoming. WDEQ-CHIA-36.

Wyoming Department of Environmental Quality, Water Quality Division (WDEQ-WQD). 2013. Rules 

and Regulations, Chapter 1, Wyoming Surface Water Quality Standards. Available at: 

http://soswy.state.wy.us/Rules/RULES/9176.pdf. Accessed September 9, 2016.

Wyoming Department of Revenue. State of Wyoming Department of Revenue 2015 Annual Report. 

Available at: https://0ebaeb71-a-84cef9ff-s-sites.googlegroups.com/a/wyo.gov/wydor/2015AnnualReport.pdf?attachauth=ANoY7collAyj0Q02_LMVofZdISeCtLmZtWCuzLQbzk

SEo4kkops1aabgL0wLApOBTladg2dIgl5NOkCIJjrkDiqadWYeQzRIb0Q0r0mUIrwXtE09p21f1

VrVkfGIAOI1L3flMVLKV_tG0o-a8GVTRWFjRi5dLP29XhJzXS1CW7gP-Hxmie0pFQS

AyQrP6zNgEMm2dTn5kNbQgaga6XzuErjF7UZ1M4ajkA%3D%3D&attredirects=0. Accessed 

September 8, 2016.

Wyoming Department of Workforce Services (WDWS). 2015. Earnings in Wyoming by County, Age & 

Gender, 2000-2014. Available at: 

http://doe.state.wy.us/lmi/earnings_tables/2015/index.htm#county. Accessed September 7, 2016. 

———. 2016a. Latest Estimates of Nonagricultural Wage and Salary Employment for Wyoming. 

Available at: http://doe.state.wy.us/lmi/news.htm. Accessed September 7, 2016. 

———. 2016b. Wyoming Labor Force Trends. Vol. 53 No. 1. Available at: 

http://doe.state.wy.us/LMI/trends/0116/0116.pdf. Accessed September 8, 2016. 

Wyoming Game and Fish Department (WGFD). 2016. Sage-Grouse Core Areas – Version 4. Available 

at: http://www.arcgis.com/home/webmap/viewer.html?webmap=0bb4ab87b95740568b10f57a7

ab5512b&extent=-114.6523,39.3415,-100.469,45.9729. Accessed February 6, 2017.

Wyoming Mining Association. 2016. The 2015-16 Concise Guide to Wyoming Coal. Available at: 

http://www.wyomingmining.org/wp-content/uploads/2015/10/2015-16-Concise-Guide-toWyoming-Coal.pdf. Accessed September 8, 2016. 

Wyoming Weed and Pest Council (WWPC). 2013. Wyoming Weed & Pest Control Act Designated Weed 

List. Available at: http://www.wyoweed.org/weeds/state-designated-weeds. Accessed February 

5, 2017. 

———. 2015. Wyoming Weed & Pest Control Law Book. Available at: http://legisweb.state.wy.us/

InterimCommittee/2016/SSD-0708APPENDIXG.pdf. Accessed February 3, 2017.
Appendix A

Public Comments on Draft Environmental 

Assessment and OSMRE’s Responses

A-1

Table A-1: Public Comments on Draft Environmental Assessment and OSMRE’s Responses

Commenter Comment Response

Wyoming Game 

and Fish

"While the areas proposed for mining overlap with antelope 

crucial winter range, the areas adjacent are already being mined 

and the animals are likely accustomed to the activity. We have 

no terrestrial wildlife concerns with the current mining plan 

modification."

Comment noted

Wyoming Game 

and Fish

“If in the future, development extends into the NE corner of 

Section 12, Township 20N, Range 100W, the project area will 

overlap the Continental Divide Sage-Grouse core area. In this 

case, please consult with the Department to complete the 

Density Disturbance Calculation Tool.”

Comment noted. OSMRE will consult with 

WGFD if future development under OSMRE 

jurisdiction overlaps the Continental Divide 

Sage-Grouse core area.

Wyoming Game 

and Fish

“We have no aquatic concerns pertaining to this mining plan 

modification.”

Comment noted

Sweetwater 

County Board 

of County 

Commissioners

“The Sweetwater County Board of County Commissioners 

strongly supports the Bridger Coal Company proposal to modify 

its surface mining plan for Federal Coal lease WYW-02727. The 

Board recognizes that this expansion plan will help sustain the 

coal mining industry which provides jobs and a tax base that 

affords a high quality of life and public services enjoyed by all 

Sweetwater County residents.”

Comment noted

Sweetwater 

County Board 

of County 

Commissioners

“To ensure coordination with the Sweetwater County 

comprehensive plan and transportation plan, Sweetwater County 

requests that the Office of Surface Mining and Reclamation and 

Enforcement considers the following in its Record of Decision:

Sweetwater County Roads: Any crossing, access to, or 

utilization of a Sweetwater County road right-of-way requires an 

access permit or license from the Sweetwater County 

Engineering Department. Project developers are encourages to 

contact the Sweetwater County Engineer to obtain necessary 

roadway permits prior to lease development.

To ensure that public roads, cattle guards and bridges are 

maintained in a safe condition and are not damaged by heavy 

construction traffic, the Sweetwater County Engineering 

Department requests that, before contractors move heavy 

equipment over county roads, they contact Gene Legerski, 

Sweetwater County Public Works Director, at (307) 872-3921.

Where Development causes significant increases in traffic or 

impacts on county roads, developers are encouraged to work 

with the Sweetwater County Engineering Department to evaluate 

and implement any identified roadway construction, 

maintenance or safety improvements that may be required. Dust 

control is of special concern.

Sweetwater County Permits: Sweetwater County Zone Changes, 

Conditional Use Permits and Construction Use Permits may be 

required for mining development related to the proposed coal 

lease expansion. Please contact Eric Bingham, Sweetwater 

County Land Use Director, at (307) 872-3916 for more 

information regarding required Sweetwater County Permits.”

OSMRE will take into account the 

Sweetwater County comprehensive plan and 

transportation plan when drafting the ROD. 

Text has been added to Section 1.4.2 of the 

EA: “The Sweetwater County 

Comprehensive Plan addresses the County’s 

present and future land use needs and 

development objectives (Sweetwater County 

2002). The Sweetwater County Growth 

Management Plan and Agreement includes a 

Master Transportation Plan (Sweetwater 

County 2011). The Master Transportation 

Plan establishes standards and rules for the 

development and management of 

transportation corridors, streets, and 

roadways. Any OSMRE decisions pertaining 

to this proposal would take into account the 

Sweetwater County Comprehensive Plan and 

Master Transportation Plan.”

Sierra Club and 

Powder River 

Basin Resource 

Council

“OSM must analyze and disclose the reasonably foreseeable 

direct, indirect, and cumulative climate impacts of the proposed 

mining, and evaluate the “significance” of these impacts. 40 

C.F.R. §§ 1508.7, 1502.16.

OSM cannot attempt to meet this obligation merely by 

comparing project level carbon dioxide emissions to total CO2

emissions from the Bridger power plant. Here, OSM quantified 

Section 4.2.1.1.2 of the EA discloses the 

agency rationale for not conducting the social 

cost of carbon protocol.

No changes required.
A-2

Commenter Comment Response

the 8.045 million tons of greenhouse gas emissions (in CO2-e) 

that would result from burning coal from the mine plan 

modification area over a 21 year period, and the approximately 

386,562 metric tons of annual CO2 emissions from this coal. 

Draft EA at 77. OSM attempts to put this into context by noting 

that the Bridger power plant emits approximately 13.2 million 

tons of CO2 each year. Id. BLM also notes that burning coal 

from the mine plan modification area would represent only 2.9% 

of the greenhouse gas emissions from annual operations at the 

Jim Bridger Power Plant. Id.

OSM must do more to meet NEPA’s hard look mandate. The 

social cost of carbon – a tool created by federal agencies and 

generally accepted in the scientific community – could be used 

here, as it would allow OSM to quantify and disclose the harm 

caused by that the project’s carbon dioxide emissions. As OSM 

explains, the social cost of carbon provides a metric for 

estimating the economic damage, in dollars, of each incremental 

ton of carbon dioxide emitted into the atmosphere. Draft EA at 

79. Moreover, OSM recognizes that the social cost of carbon 

“can be a helpful tool to assess the benefits of CO2 reductions.”

Id.

Yet OSM offers four excuses for not using the social cost of 

carbon, none of which have merit. First, OSM hangs its hat on 

the notion that the social cost of carbon “was designed for 

rulemakings and not project-level analyses; therefore, the SCC 

protocol was not used here.” Draft EA at 79. Yet there is nothing 

about the science behind the social cost of carbon that makes it 

more applicable in the regulatory setting than to project-level 

NEPA processes, and thus its specific application in the 

regulatory context does not detract from its utility here. The 

federal district court in Montana, the federal district court in 

Colorado, and the D.C. Circuit Court have all rejected projectlevel NEPA reviews for not incorporating the social cost of 

carbon into their climate analyses. Sierra Club v. FERC, No. 16-

1329, 2017 WL 3597014 (D.C. Cir. Aug. 22, 2017), MEIC v. 

OSM, 9:15-cv-00106-DWM, Order (Aug. 18, 2017), High 

Country Conservation Advocates v. U.S. Forest Service, 52 F. 

Supp. 3d 1174 (D.Colo. 2014).

Second, OSM asserts that NEPA does not require a cost-benefit 

analysis. Draft EA t 79. OSM’s point misses the mark. The 

social cost of carbon should be used here because it provides 

OSM and the public with meaningful information that OSM has 

otherwise refused to provide; its utility is not tied to cost benefit 

analyses. NEPA specifically requires federal agencies to analyze 

and disclose the environmental effects of their actions, including 

the “aesthetic, historic, cultural, economic, social, or health” 

impacts. 40 C.F.R. § 1508.8. The social cost of carbon is a tool 

that would allow OSM to meet this NEPA obligation. Where 

“information relevant to reasonably foreseeable significant 

adverse impacts cannot be obtained because the overall costs of 

obtaining it are exorbitant or the means to obtain it are not 

known,” NEPA regulations direct agencies to evaluate a 

project’s impacts “based upon theoretical approaches or research 

methods generally accepted in the scientific community.” 40 

C.F.R. § 1502.22(b)(4). The social cost of carbon is based on 

generally accepted research methods and years of peer-reviewed 

scientific and economic studies. It is a simple tool that is easy for 

federal agencies to use and easy for the public to understand. 

Putting a dollar figure on each ton of CO2 emitted as a result of a 

federal project places climate impacts in a context that both 

decision makers and the public can readily comprehend. The 
A-3

Commenter Comment Response

social cost of carbon is backed by years of peer reviewed 

scientific and economic research, it is designed to be updated to 

reflect the most up-to-date information, and it has already been 

used by federal agencies in both rulemaking decisions and 

project-level reviews under NEPA.

Third, OSM asserts that, without the inclusion of a full costbenefit analysis, quantifying social costs would present only part 

of the necessary data. Draft EA at 79. This is unavailing. Simply 

because a tool does not address every aspect of a problem does 

not mean that OSM’s analysis would be less informed by 

answering part of the question. And OSM never states that it 

couldn’t provide those other costs and benefits. Nor does OSM 

offer anything to explain why offering partial benefits provides 

“meaningful insight” but providing partial costs would not. This 

excuse is simply another dodge so that OSM does not have to 

own up to the true climate costs of its decision to approve the 

mine plan modification. As OSM well knows, the federal district 

court in Montana recently overturned an OSM EA for the Bull 

Mountain Mine based in part on OSM’s refusal to use the social 

cost of carbon to analyze climate impacts, and there the agency 

did not include a full cost-benefit analysis. MEIC v. OSM, 9:15-

cv-00106-DWM, Order (Aug. 18, 2017). Moreover, federal 

agencies’ obligation to analyze the costs associated with

greenhouse gas emissions through NEPA was directly affirmed 

by the court in High Country Conservation Advocates v. U.S. 

Forest Service, 52 F. Supp. 3d 1174 (D.Colo. 2014). In its 

decision, the court identified the social cost of carbon protocol as 

a tool to “quantify a project’s contribution to costs associated 

with global climate change.” Id. at 1190. After rejecting the 

agency’s excuses for not using the tool, the court concluded: 

“[t]he critical importance of [climate change] . . . tells me that a 

‘hard look’ has to include a ‘hard look’ at whether this tool, 

however imprecise it might be, would contribute to a more 

informed assessment of the impacts than if it were simply 

ignored.” Id. at 1193. The same is true here.

Fourth, OSM states that the social cost of carbon is no longer 

federal policy. Draft EA at 79. Although President Trump 

recently disbanded the IWG and rescinded its Technical Support 

Document – he did so on political, not scientific grounds.1 The 

President’s Executive Order directed federal agencies to refer to 

OMB Circular A-4 when evaluating greenhouse gas emission 

impacts from federal regulations. Circular A-4 instructs agencies 

to account for both the costs and benefits and to account for 

global impacts when evaluating impacts “likely to have effects” 

outside the U.S.2 The social cost of carbon allows OSM to 

evaluate those impacts here. Similarly, OSM could simply use 

one of the DICE, PAGE, or FUND models that the social cost of 

carbon is based on, as nothing in federal policy undermines the 

validity or application of those models.”

Sierra Club and 

Powder River 

Basin Resource 

Council

“NEPA also requires a detailed analysis of “cumulative” effects, 

“the incremental impact of the action when added to other past, 

present, and reasonably foreseeable future actions.” 40 C.F.R. §§ 

1508.7, 1508.25(c).

Here OSM improperly refused to even consider cumulative 

climate impacts. Chapter 5 of the Draft EA proves zero analysis 

or discussion of cumulative climate impacts. Draft EA at 95-103.

This blatantly contradicts the NEPA obligation to consider 

cumulative impacts. “The impact of greenhouse gas emissions 

on climate change is precisely the kind of cumulative impacts 

analysis that NEPA requires agencies to conduct.” Ctr. for 

Section 4.2.1.1.2 and Section 5.2.1.3 of the 

EA disclose the potential impacts of 

greenhouse gas emissions on the environment 

as well as the rationale for not conducting a 

separate analysis of cumulative impacts of 

greenhouse gas emissions. OSMRE 

concluded that potential direct and indirect 

impacts of GHGs would be short-term and 

minor.

No change required.
A-4

Commenter Comment Response

Biological Diversity v. Nat’l Highway Traffic Safety Admin., 

538 F.3d 1172, 1217 (9th Cir. 2008).

[T]he fact that climate change is largely a global phenomenon 

that includes actions that are outside of [the agency’s] control . . 

. does not release the agency from the duty of assessing the 

effects of its actions on global warming within the context of 

other actions that also affect global warming.

Id.

Analysis of cumulative impacts protects against “the tyranny of 

small decisions,” Kern v. Bureau of Land Mgmt., 284 F.3d 

1062, 1078 (9th Cir. 2002), by confronting the possibility that 

agency action may contribute to cumulatively significant effects 

even where the impacts appear insignificant in isolation. 40 

C.F.R. §§ 1508.7, 1508.27(b)(2). See Grand Canyon Trust v. 

Fed. Aviation Admin., 290 F.3d 339, 342 (D.C. Cir. 2002) 

(evaluating the environmental consequences of a proposed 

action, the agency “must give a realistic evaluation of the total 

impacts and cannot isolate a proposed project, viewing it in a 

vacuum.”).

At a minimum, OSM must disclose the climate impacts of this 

mine expansion, combined with past and reasonably foreseeable 

future mine expansions at Jim Bridger complex, including the 

expansion furthered by the coal exploration license proposed by 

Bridger Coal Company and announced by BLM on Friday, 

September 1, 2017. Application number WYW185631. 82 Fed. 

Reg. 41,647 (Sept. 1, 2017).3 OSM includes “exploratory 

drilling for coal in support of the Bridger Mine complex” and 

“operations of the Jim Bridger Power Plant” in its summary of 

“past and present actions” included in the cumulative impacts 

section of the draft EA, Draft EA at 97, yet OSM makes no 

attempt to consider the climate impact of these future actions.”

Sierra Club and 

Powder River 

Basin Resource 

Council

“OSM has failed to provide any analysis of whether its 

continued approval of small mine plan amendments and 

modifications is extending the life of the Jim Bridger power 

plant.

OSM’s draft EA entirely fails to address the key climate 

question: whether there is a measurable difference in greenhouse 

gas emissions between approving and rejecting this proposed 

modification, combined with other past, present, and reasonably 

foreseeable future mining operations at the Jim Bridger Mine 

complex. The fact that this is one small, incremental amount of 

coal from the larger mine complex, ignores the broader impact 

of operating the Bridger Mine complex. OSM must address 

whether continued expansions at the mine are essentially 

keeping the power plant operating. Without knowing that key 

piece of information, OSM cannot make an informed decision 

on whether these small changes to the mine plan are worth 

approving or should be rejected in favor of the No Action 

alternative.

Over the past five years, Energy Information Administration 

(EIA) data shows that the Jim Bridger Mine has received coal 

from only two sources: the Jim Bridger Mine complex, and the 

Black Butte/Leucite Hills operation. As documented in the 

attached spreadsheet, compiled from EIA form 523 data, over 

the past five years the Jim Bridger mine complex has supplied 

between 41 and 71 percent of the coal burned by the Jim Bridger 

Power Plant, with the average being around 65 percent.4 OSM 

must disclose these figures and assess whether its continued 

approvals at the mine are keeping the power plant open. And if 

According to CEQ guidance, you "may 

contrast the impacts of the proposed action 

and alternatives with the current condition 

and expected future condition in the absence 

of the project." With or without the proposed 

mine permit modification area, the Bridger 

Mine Complex would continue to operate 

until 2037. However, without the proposed 

mine permit modification area, the Bridger 

Mine Complex would experience a drop in 

annual production of between 3% and 5%. 

Any additional analysis of the use of coal 

from other mines within or outside of the 

U.S. at the Jim Bridger Power Plant is 

outside the scope of this EA.

No change required.
A-5

Commenter Comment Response

that is the case, then OSM must be honest that the cumulative 

impact of its decisions to expand mining operations is keeping 

open a heavily polluting power plant that would otherwise 

reduce or cease operations.”

Sierra Club and 

Powder River 

Basin Resource 

Council

“NEPA requires OSM prepare a full Environmental Impact 

Statement (EIS) for the proposed mine expansion instead of the 

more limited EA and unsigned Finding of No Significant Impact 

(FONSI) it has prepared thus far. This proposal is part of a larger 

mine-power plant complex, the environmental impacts of which 

have never been assessed via an environmental impact statement

rather than limited environmental assessments. See Sierra Club 

scoping comments to OSM (July 1, 2016). Here, the agency 

must prepare an Environmental Impact Statement (EIS) to fulfill 

its duties under NEPA.

NEPA requires federal agencies to prepare an EIS rather than a 

more limited EA for any “major federal action[] significantly 

affecting the quality of the human environment.” 42 U.S.C. § 

4332(2)(C). Agencies must prepare an EIS if there are 

“substantial questions whether a project may have significant 

effect,” Blue Mountains Biodiversity Project v. Blackwood, 161 

F.3d 1208, 1212 (9th Cir. 1998), and an agency “cannot avoid 

preparing an EIS by making conclusory assertions that an 

activity will have only an insignificant impact on the 

environment.” Ocean Advocates v. U.S. Army Corps of Eng’rs, 

402 F.3d 846, 864 (9th Cir. 2004).

Here the direct, indirect, and cumulative impacts of coal mining 

and combustion associated with the proposed expansion will 

undoubtedly have a significant effect on the environment. The 

proposed expansion will assuredly result in the release of carbon 

dioxide into our atmosphere. When combined with other mine 

expansions, including those currently under evaluation by OSM, 

the proposal will undoubtedly result in hundreds of millions of 

tons of greenhouse gas emissions – making them significant by 

any measure.

A proposal may require an EIS if its effects are “likely to be 

highly controversial.” 40 C.F.R. § 1508.27(b)(4). Increasing 

methane and carbon dioxide emissions by expanding coal 

mining into federal lands is particularly controversial at this 

time, as doing so may interfere with efforts to meet our 

international climate commitments and could make it impossible 

to keep global warming limits within manageable thresholds.”

As a factor for determining within the 

meaning of 40 CFR 1508.27(b)(4) (whether 

or not to prepare a detailed EIS) 

“controversy” is not equated with “the 

existence of opposition to a use.” Northwest 

Environmental Defense Center v. Bonneville 

Power Administration, 117 F.3d 1520, 1536 

(9th Cir. 1997). The term ‘highly 

controversial’ refers to instances in which “a 

substantial dispute exists as to the size, 

nature, or effect of the major federal action 

rather than the mere existence of opposition 

to a use” Hells Canyon Preservation Council 

v. Jacoby, 9 F.Supp.2d 1216, 1242 (D. Or. 

1998). NEPA analysis has been completed 

for the already permitted areas of the Bridger 

Mine Complex. The federal action under 

review is the proposed modification of an 

existing mining permit. As the commenter 

acknowledges, NEPA requires federal 

agencies to prepare an EIS for any “major 

federal action significantly affecting the 

quality of the human environment”. The 

OSMRE has determined, through the analysis 

in the EA, that the proposed mining plan 

modification would not significantly affect 

the quality of the human environment. 

Therefore, the preparation of an EIS is not 

required.

No change required.

WildEarth 

Guardians

“We are extremely concerned that OSM has never prepared an 

independent analysis of the effects of coal mining at the Jim 

Bridger coal mine and connected Jim Bridger power plant to the 

human environment. In our prior comments, we pointed to the 

need for OSM to prepare an EIS. These comments do not appear 

to have been adequately addressed in the EA. The Jim Bridger 

coal mine is a major supplier to the nearby Jim Bridger power 

plant, the largest coal-fired power plant in Wyoming. U.S. 

Department of Energy, The Energy Information Administration 

(EIA) EIA-923 Monthly Generation and Fuel Consumption, 

Time Series File, December 2016, available at: 

http://www.eia.gov/electricity/data/eia923/. Together, these 

operations pose tremendous impacts to public lands in the 

region, air quality, climate change, water quality, and wildlife. 

Combined with the impacts of past, present, and reasonably 

foreseeable future impacts in the region, the proposed mining 

plan modification would appear to pose significant impacts, 

warranting the need for OSM to prepare an EIS pursuant to 

The EA has analyzed the effects on and from 

climate change and determined that due to 

the life of mine increasing by 13 years under 

the Proposed Action the direct effects would

be short-term and minor. Approvals of 

federal mining plans and mining plan 

modifications have been made in the area for 

several decades. The project design features 

and reclamation plan would reduce the 

effects on the environment; or, in some cases, 

would improve the current condition (e.g., 

soils, vegetation, and wildlife habitat (EA 

Section 2.1.1). No other anticipated effects 

have been identified that are scientifically 

controversial. An EIS was completed by 

OSMRE for the San Juan Mine and San Juan 

Generating Station because the Proposed 

Action at the mine would necessitate changes 
A-6

Commenter Comment Response

NEPA. The history of approvals during the life of the mine 

indicates only EAs have been undertaken, not a more rigorous 

EIS, which is wholly insufficient to allow continued operations 

at the Jim Bridger mine complex.

In similar circumstances, OSM enacted a full EIS process to 

analyze impacts of a mining plan modification related to federal 

coal lease NM-99144 at the San Juan Mine. Fed. Reg. 84,14745. 

In comparison, the San Juan Generating Station generates 1,848 

megawatts of electricity; the larger Jim Bridger Power Plant 

generates 2,110 megawatts. See, San Juan Generating Station 

http://www.pnm.com/systems/sj.htm; see also, Jim Bridger Plant 

Fact Sheet 

http://www.pacificorp.com/content/dam/pacificorp/doc/Energy_

Sources/EnergyGeneration_FactSheets/RMP_GFS_Bridger.pdf. 

The San Juan Generating Station emits 11,881,970 tons of CO2; 

the Jim Bridger Power Plant emits even more at 14,732,724 tons 

of CO2. North American Power Plant Air Emissions, Carbon 

Dioxide Emissions, available at: 

http://www2.cec.org/site/PPE/co2emissions. These are only two

comparison points among many, however, OSM previously 

determined that the impacts of a smaller complex that emits less 

CO2 than the Jim Bridger Power Plant warranted an EIS. Thus, 

the decision to merely undergo an EA for the larger Jim Bridger 

complex, which emits higher levels of CO2 and has more 

significant environmental implications, is seemingly arbitrary.

Moreover, the current finding that impacts were not sufficiently 

significant to warrant an EIS is marred against the fact that an 

EIS was completed for the Jim Bridger Power Plant in 1972. 

Final Environmental Impact Statement for the Jim Bridger 

Thermal-Electric Generation Project. 7/26/1972, available at: 

https://ia902707.us.archive.org/20/items/finalenvironment5103u

nit/finalenvironment5103unit.pdf. Put more pointedly, 45 years 

ago, the impacts of the Jim Bridger Power Plant were significant 

enough to warrant a full environmental analysis, signaling that 

those same impacts are significant enough to warrant an EIS 

now in analyzing the modification. Further, while the 1972 EIS 

analysis was current at the time, since then, significant 

environmental advances and legislation has been enacted. The 

1972 EIS was signed before the Endangered Species Act (1973); 

SMCRA (1977); Clean Air Act amendments (1977, 1990); the 

invention of scrubber technology for removing air pollution 

(1979); and before climate change was widely accepted, among 

other events.

Even 45 years ago, the 1972 EIS stated that “The stack 

emissions [...] have by far the most significant impact on the 

high-altitude desert environment.” Id. at I-1. Since then, 

Wyoming’s coal companies have set new production records 

every year, levels which OSM could not have forecasted or 

accounted for in determining whether the cumulative impacts of 

nearby mine or power plants were significant at that time. In 

1972, only 10.9 million tons of coal were mined from Wyoming. 

Thilenius, John & Glass, Gary. “Surface Coal Mining in 

Wyoming: Needs for Research and Management.” Journal of 

Range Management 27(5), September, 1974, available at: 

https://journals.uair.arizona.edu/index.php/jrm/article/viewFile/6

352/5962. In 2015, production spiked to 375.7 million tons of 

coal mined from Wyoming. US Energy Information 

Administration. Annual Coal Report, created 11/3/2016, 

available at: https://www.eia.gov/coal/data.php#production. As 

another point of comparison, in 1972 the Jim Bridger Power 

Plant used an estimated 29,200 acre-feet of water per year. In 

to the operation of the power plant meaning 

the power plant had to be considered as a 

connected action under NEPA. This is not 

true for the Jim Bridger Mine and Jim 

Bridger Power Plant. Analysis of potential 

impacts from mining and combusting 

Proposed Action coal was completed for all 

resources listed in Table 3-1 in the EA. 

Under the Proposed Action, production levels 

would remain the same, but the Proposed 

Action would allow the mine life to be 

extended by 13 years, when combined with 

future mining on adjacent and private lands. 

According to NEPA guidance provided in 

BLM Handbook H-1790-1, an EA is intended 

to be a concise public document that provides 

sufficient evidence and analysis for 

determining the significance of effects from a 

proposed action (40 CFR 1508.9) and that 

serves as a basis for reasoned choice. Based 

upon the EA analysis, either an EIS or a 

FONSI will be prepared. OSMRE has 

completed the EA process and has not 

identified significant adverse effects. 

Therefore, an EIS is not required. Impact 

intensity is described in Section 4.1of the EA. 

Section 4.2.1.1.2 and Section 5.2.1.3 of the 

EA disclose the potential impacts of 

greenhouse gas emissions on the environment 

as well as the rationale for not conducting a 

separate analysis of cumulative impacts of 

greenhouse gas emissions. OSMRE 

concluded that potential direct effects of 

GHGs from mining would be short-term and 

minor, and indirect effects of combustion 

would be long-term and moderate.

No change required.
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Commenter Comment Response

2016, the Jim Bridger Power Plant was permitted to use up to 

34,320 acre-feet per year, and despite lower production in 2016, 

actually used 23,866 acre-feet per year. All that to say, if the 

agency determined that the water use and sheer amount of 

production was significant enough to warrant a full 

environmental evaluation, that determination is all the more 

necessary now, further scrutinized under today’s water 

shortages, climate change problems, and environmental 

legislation. Thus, OSM must analyze the environmental impacts 

as the 1972 EIS fails to address significant environmental 

impacts that should be weighed in determining whether to 

approve the modification.

Finally, OSM’s decision to issue an EA in order to avoid 

preparing its own EIS or a supplemental EIS, is not supported by 

Interior Department NEPA regulations at 43 C.F.R § 46.140. 

These regulations state that:

An environmental assessment may be prepared, and a finding of 

no significant impact reached, for a proposed action with 

significant effects, whether direct, indirect, or cumulative, if the 

environmental assessment is tiered to a broader environmental 

impact statement which fully analyzed those significant effects.

In this case, an EA is insufficient because a proper EIS has never 

been prepared. In fact, the EA prepared for the proposed mining 

plan modification does not even tier to an EIS. It is very 

concerning that for such a massive industrial operation with such 

an extensive footprint on the landscape of the United States of 

America, an EIS has never been prepared. Moreover, we have 

raised these issues several times surrounding different leases 

under Bridger Coal Mine. In a 2016 appeal of a different lease 

modification at Jim Bridger Mine, we reasoned that “the agency 

entirely failed to assess the significance of these emissions in the 

context of their climate impacts. This is a significant 

shortcoming and indicates there is no support, implicit or 

otherwise, that the impacts of the greenhouse gas emissions will 

not be significant and therefore justify a FONSI.” WildEarth 

Guardians’ Statement of Reasons, Appeal of the Jim Bridger 

Lease Modification, 6 IBLA No. 2016-0079. (Attached as 

Exhibit 1).”

WildEarth 

Guardians

“The EA insufficiently analyzed water quality impacts. With 

regards to water quality, OSM must fully analyze and assess 

water quality impacts to ensure compliance with state water 

quality standards. OSM must identify all existing water quality 

problems in the area that will be directly, indirectly, and 

cumulatively affected by the proposed action and disclose any 

contribution the proposed action will make to those water quality 

problems. OSM must ensure that the reasonably foreseeable 

consequences of its actions ensure compliance with relevant 

water quality standards in accordance with the Clean Water Act.

We are further concerned that the EA fails to adequately analyze 

and assess water quantity impacts. The EA states that annual 

water usage for dust suppression at the Jim Bridger Mine 

Complex ranges between 70 million and 170 million gallons of 

water per year. See, Jim Bridger Mine Environmental 

Assessment, § 2.2.1.2.7 (hereinafter “EA”). Additionally, the EA 

states that underground facilities are estimated to require 105 

million gallons per year. EA § 2.1.1.8. What is missing from 

these recitations of data is whether these amounts are significant, 

and how the Agency determined the threshold of significance. A 

second example of inadequate analysis is the single mention of 

the Green River Pipeline in the EA, without any context as to 

Impact intensities are defined in Section 4.1 

of the EA. Impacts to surface water quantity 

are described in Section 4.10.1.1.1 of the EA. 

Given that the streamflow in the analysis area 

is primarily ephemeral, impacts to water 

quality would likely be short-term, minor, 

and limited in geographical extent if they 

were to occur. Because of the relatively small 

size of the mining plan modification area and 

the minimal impact on water quantity that 

previous and existing mining operations in 

the surface water impact analysis area have 

had, the Proposed Action is expected to have 

a short-term, minor impact on surface water 

quantity. According to NEPA guidance 

provided in BLM Handbook H-1790-1, an 

EA is intended to be a concise public 

document that provides sufficient evidence 

and analysis for determining the significance 

of effects from a proposed action (40 CFR 

1508.9) and that serves as a basis for 

reasoned choice. Based upon the EA analysis, 
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Commenter Comment Response

how it will be impacted, or what the significance of the pipeline 

is. Id. Further, the EA demonstrates that the total acres of past, 

present, and reasonably foreseeable future actions causing 

surface disturbance in the groundwater is approximately 61,106 

acres. EA § 5.2.3.9.2. What is left to be examined is the level of 

significance, and the threshold of that determination. These are 

only a handful of examples in which OSM merely enumerated 

current figures, and left the public to guess at their context, and 

therefore how the Agency determined their significance. Under 

NEPA, agencies are tasked with the independent obligation to 

assess significance, not pass the duty off to some undefined 

entity. In this particular case, OSM has not fully accounted for 

the water use at the Jim Bridger Complex as a whole. Therefore, 

OSM has not met its burden in providing sufficient evidence that 

the impacts of the modification would not be significant, 

warranting an EA.”

either an EIS or a FONSI will be prepared. 

OSMRE has completed the EA process and 

has not identified significant direct, indirect, 

or cumulative adverse effects to water quality 

or quantity. Therefore, an EIS is not required. 

The Jim Bridger Power Plant is not a 

connected action per 40 CFR 1508.21(a)1, 

therefore, water quality, quantity, and usage 

at the power plant have not been analyzed in 

the EA.

Annual water usage levels would remain the 

same, but the Proposed Action would allow 

the mine life to be extended by 13 years, 

when combined with future mining on 

adjacent and private lands. The impact on 

water usage would be short-term and minor.

No change required.

WildEarth 

Guardians

“The EA fails to analyze and address impacts to air quality 

related to the combustion of coal from the Jim Bridger Mine. 

OSM must fully analyze and assess direct, indirect, and 

cumulative impacts to air quality, including impacts to air 

quality in the context of all NAAQS, prevention of significant 

deterioration (“PSD”) increments for Class I and II areas, and 

visibility impacts to Class I areas.

We are particularly concerned over the impacts of the mining to 

NAAQS for ozone, particulate matter, and nitrogen dioxide 

(which is produced during blasting, as well as emitted from 

engines). OSM must specifically address all emissions sources, 

particularly those that are not explicitly permitted by the State of 

Wyoming (including blasting emissions). We request that OSM 

further address the impacts of fugitive emissions, including 

fugitive volatile organic compound and nitrogen dioxide 

emissions associated with blasting and stripping of overburden. 

OSM must quantify emissions from the mine to ensure an 

accurate and adequate analysis and assessment of air quality 

impacts.

While OSM may claim that it is appropriate to presume there 

will be no significant impacts by virtue of the mine and the Jim 

Bridger Power Plant being subject to air quality permitting, this 

claim is belied by the fact that the Jim Bridger Power Plant is 

currently out of compliance with the Clean Air Act. According 

to the U.S. Environmental Protection Agency’s (“EPA’s”) 

Enforcement and Compliance History Online Database, the 

Power Plant is a High Priority Violator and has been out of 

compliance since at least 2014, if not earlier. (see Exhibit 2). 

OSM must analyze and assess air quality impacts taking into 

account this noncompliance.

We are also concerned that current monitoring for the area is not 

even occurring. While the EA states that emissions from the 

mine are not contributing to ozone exceedances, this statement 

does not represent an accurate assessment when monitoring 

stations are not even in the area. One nearby air quality 

monitoring station, at Moxa Arch, is over 80 miles away, the 

second, in Wamsutter, Wyoming, is 50 miles away. What’s 

more, the EA did not contain any expression of whether the 

mileage of the air quality monitoring system to the mine would 

cause an impact to the monitoring results. In order to correct this 

flawed assessment, OSM must prepare a modeling analysis. 

Additionally, OSM did not analyze quantified fugitive emissions 

from particulate matter from excavation, hauling, and 

Impacts to air quality are discussed in Section 

4.2 of the EA. Both direct impacts and 

indirect impacts are expected to be short-term 

and minor. Section 5.2.3.1 discloses potential 

cumulative impacts to air quality.

At this time, titania suboxides, specifically 

Magnéli phases (Ti x O2x−1) that are the 

subject of study in the referenced Nature 

article, have not been listed by the EPA as 

either a criteria or hazardous air pollutant; 

therefore, there are currently no monitoring 

requirements for these compounds in the 

United States. Without data from monitoring, 

the presence of these compounds in the 

environment at or near the Jim Bridger Mine 

and Jim Bridger Power Plant is unknown. 

The article referenced by the commenter 

states that further, more comprehensive 

studies are necessary to characterize potential 

toxicity and pathways have not been found at 

this time. Until more comprehensive, 

thorough studies have been conducted and 

peer reviewed by the scientific community, 

and related guidance has been issued by EPA, 

the Magneli phase impacts are too 

speculative and therefore not helpful to the 

decision maker.

Text has been added to Section 3.3.2.1.2 of 

the EA: “The EPA has identified High 

Priority Violations of the CAA at the Jim 

Bridger Power Plant. High Priority 

Violations are violations of regulations 

authorized by the CAA that warrant 

additional scrutiny to ensure that state, local, 

territorial, and tribal agencies respond to such 

violations in an appropriate manner and, if 

needed, have access to federal assistance. 

However, the analysis of impacts to air 

resources assumes that the Jim Bridger 

Power Plant would comply with its air 

quality permit requirements and the CAA.” 

Operation of the Jim Bridger Power Plant is 

not a connected action to the Proposed 
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Commenter Comment Response

reclamation activities. Further, a recent study found a new toxin 

existing in coal combustion emissions. Nature Communications 

8, Article number: 194(2017) doi:10.1038/s41467-017-00276-2, 

available at: https://www.nature.com/articles/s41467-017-

00276-2. The study suspected that in the U.S., scrubbers capture 

the material, reducing its prevalence, however, there is no 

monitoring of this particular harmful toxin, which contributes to 

the estimated 3 million air-pollution related deaths worldwide. 

Roston, Eric. “Coal Plants Might be More Toxic Than We 

Thought.” Bloomberg News. 8/8/2017, 

https://www.bloomberg.com/news/articles/2017-08-08/coalplants-might-beeven-more-toxic-than-we-thought. Thus, OSM 

must include an analysis of this particular new toxin’s 

prevalence in the effects of coal combustion.

Until the Agency has corrected these deficiencies in monitoring 

data and analyses, the Agency cannot come to the conclusion 

that the impacts will not be significant.”

Action.

As explained in Section 3.3.2.1.1 of the EA, 

“A portion of Sweetwater County (the Upper 

Green River Basin area) is currently a 

nonattainment area for O3 (8-hour) (EPA 

2016b). The Bridger Mine Complex is not in 

the Upper Green River Basin and is in an 

area currently considered in attainment with 

NAAQS (WDEQ-AQD 2012). As a result, 

the General Conformity Rule does not apply 

to the Proposed Action (the General 

Conformity Rule ensures that actions taken 

by federal agencies in nonattainment and 

maintenance areas are consistent with a 

State’s plans to meet NAAQS [CAA Section 

176(c)]). The WDEQ Air Quality Division 

(WDEQ-AQD) has also established its own 

ambient air quality standards—the Wyoming 

Ambient Air Quality Standards (WAAQS).” 

The Wyoming Department of Environmental 

Quality does not require BCC to monitor 

ozone as part of its mining permit.

Table 3-4 in the EA quantifies existing 

fugitive dust emissions at the mine. Because 

production levels would not change under the 

Proposed Action, fugitive dust emissions 

would remain the same, but the mine life 

would be extended 13 years when combined 

with future mining on adjacent and private 

lands.

WildEarth 

Guardians

“OSM has failed to analyze and assess the full climate change 

impacts of approving the modification. OSM must analyze and 

assess the full extent of climate change impacts of approving the 

proposed mining plan. The Proposed Action would result in a 

continuation of existing mining levels at the Bridger Mine 

Complex through 2037; therefore, direct effects on greenhouse 

gases (GHG) would also continue at current levels. By not 

approving the mining permit, the production levels would 

decrease from 3% to 5% after 2025, as opposed to the proposed 

action. To this end, we request OSM quantify the direct, indirect, 

and cumulative greenhouse gas emissions that would result from 

approving the proposed mining plan, which would maintain 

production levels, including emissions of methane (including 

from mining activities), carbon dioxide, and other greenhouse 

gases that have been found to harm public health.”

Section 4.2.1.1.2 of the EA discloses the 

potential direct and indirect impacts of 

greenhouse gas emissions on the 

environment. OSMRE concluded that 

impacts of GHGs would be short-term and 

minor. Since the analyses provided in section 

4.2.1.1.2 includes direct and indirect effects 

analysis for GHG emissions, and due to the 

global nature of climate change, and the 

difficulty therefore of predicting climate 

change impacts caused by an incremental 

increase in GHG emissions from specific 

actions separately or together, a separate 

cumulative impacts analysis for GHG 

emissions is not appropriate and has not been 

conducted in the EA.

No change required. .

WildEarth 

Guardians

“Additionally, we find it concerning that OSM touted the benefit 

of employing 230 people through the depreciable life of the 

mine, 2037, without also considering the costs of continued 

combustion and extraction through that same period. The EA 

stated: “The Proposed Action represents an estimated economic 

benefit to this area through 2037 of wages, goods and services 

related to the mining operation, and payment of federal, state, 

and local taxes. The socioeconomic benefits are derived from 

payroll, insurance, retirement contributions, local expenditures, 

taxes, and federal coal royalty payments.” Jim Bridger Coal 

Mine Complex, Federal Coal Lease WYW-02727, Mining Plan 

Modification, Finding of No Significant Impact, p. 3. This type 

Section 4.2.1.1.2 of the EA discloses the 

agency rationale for not conducting the social 

cost of carbon protocol.

No changes required.
A-10

Commenter Comment Response

of one-sided analysis is a principal example of the inadequate 

evaluation engaged in by OSM. To that end, a federal district 

court in Montana recently ruled that a NEPA analysis that 

included the economic benefits of a project was incomplete 

without an assessment of the carbon costs that would result from 

the development. Mont. Envtl. Info. Ctr. v. U.S. Office of 

Surface Mining, No. CV 15-106-M-DWM (D. Mont. Aug. 14, 

2017) (Attached as Exhibit 3).

We also request that OSM analyze and assess the extent to 

which these emissions are likely to contribute to global climate 

change. In this case, it appears that any level of extended carbon 

dioxide emissions would pose significant impacts. However, at a 

minimum, to properly assess climate impacts under NEPA, 

OSM must analyze and assess the cost of carbon emissions using 

the social cost of carbon protocol.

OSM must analyze and assess the climate impacts of mining the 

Jim Bridger Mine using the social cost of carbon protocol. The 

social cost of carbon protocol for assessing climate impacts is a 

method for “estimat[ing] the economic damages associated with 

a small increase in carbon dioxide (CO2) emissions, 

conventionally one metric ton, in a given year [and] represents 

the value of damages avoided for a small emission reduction (i.e. 

the benefit of a CO2 reduction).” EPA, “Fact Sheet: Social Cost 

of Carbon” (Nov. 2013) at 1 (Attached as Exhibit 4). The 

protocol was developed by a working group consisting of several 

federal agencies, including the U.S. Department of Agriculture, 

EPA, CEQ, and others, with the primary aim of implementing 

Executive Order 12866, which requires that the costs of 

proposed regulations be taken into account.

In 2009, an Interagency Working Group (“IWG”) was formed to 

develop the protocol and issued final estimates of carbon costs in 

2010. Interagency Working Group on Social Cost of Carbon, 

“Technical Support Document: Social Cost of Carbon for 

Regulatory Impact Analysis Under Executive Order 12866” 

(Feb. 2010) (Attached as Exhibit 5). These estimates were then 

revised in 2013 by the IWG. Interagency Working Group on 

Social Cost of Carbon, “Technical Support Document: Technical 

Update of the Social Cost of Carbon for Regulatory Impact 

Analysis Under Executive Order 12866” (May 2013) (Attached 

as Exhibit 6). In July 2014, the U.S. Government Accountability 

Office (“GAO”) confirmed that the Interagency Working 

Group’s estimates were based on sound procedures and 

methodology. GAO, “Regulatory Impact Analysis, Development 

of Social Cost of Carbon Estimates,” GAO-14-663 (July 2014) 

(Attached as Exhibit 7). The social cost of carbon estimates were 

again revised in 2015. Interagency Working Group on Social 

Cost of Carbon, “Technical Support Document: Technical 

Update of the Social Cost of Carbon for Regulatory Impact 

Analysis Under Executive Order 12866” (modified July 2015) 

(Attached as Exhibit 8).

IWG’s most recent estimate was $50 in global damages per ton 

of carbon dioxide, based on year 2020 emissions, converted 

from 2007 to 2017 dollars. Interagency Working Group on the 

Social Cost of Greenhouse Gases (IWG), “Technical Support 

Document: Technical Update of the Social Cost of Carbon for 

Regulatory Impact Analysis Under Executive Order 12866” 

(2016) (Attached as Exhibit 9).

While Trump’s Executive Order 13783 technically disbanded 

the IWG in March, 2017, in a recent letter published in the 

journal, Science, scholars urged the government and private 
A-11

Commenter Comment Response

sector to continue using IWG’s the estimate of $50 per ton of 

carbon dioxide, as it is the “best estimate of the social cost of 

greenhouse gases”. “Best Cost Estimate of Greenhouse Gases.” 

Revesz, R. Science 357 (6352), 655. DOI: 

10.1126/science.aao4322 (Attached as Exhibit 10). In the letter, 

scholars reasoned that IWG’s estimated “already are the product 

of the most widely peer-reviewed models and best available 

data.” Id. Thus, OSM’s statement that “the science used in the 

models lags behind the most recent research,” is false, based on 

the recent letter published in Science, indicating that it is still 

current and the best model.

The social cost of carbon provides decision makers and the 

public with an informative, accessible mechanism for both 

analyzing and understanding the climate impacts of a proposed 

decision. Although agencies such as OSM and the Forest Service 

often quantify the amount of carbon dioxide or CO2-e (carbon 

dioxide equivalent) emissions from mining and burning coal 

from federal leases, these agencies have not yet taken the next 

step of consistently employing the social cost of carbon to tell 

the public about the impact of those emissions. An isolated 

calculation of the amount of carbon emissions that would result 

from a particular project does not provide any meaningful 

insight as to the effect that those emissions will have on our 

climate. By contrast, the social cost of carbon offers an actual 

estimate of the damage caused by each incremental ton of 

carbon emissions.

A primary reason OSM gave for not completing a social cost of 

carbon analysis is that without a “thorough cost-benefit analysis 

incorporating the social benefits of energy production, the 

inclusion of an SCC analysis in this EA would present only part 

of the necessary data.” EA at 79. The social cost of carbon 

describes those damage estimates in monetary terms, which are

far easier for decision makers and the public to comprehend and 

contextualize than tons of CO2-e. In doing so, the social cost of 

carbon provides a concrete assessment of a project’s social and 

environmental impacts and provides a tangible sense of the scale 

of damage that both the public and decision makers can readily 

understand. As explained by one legal commentator, the social 

cost of carbon “allow[s] agencies to consider those GHG 

emissions . . . in a meaningful way,” and that “assigning a price 

to carbon emissions – even a conservative price – makes the cost 

of those emissions concrete for agency decision makers.” 

Squillace, Mark & Hood, Alexander, NEPA, Climate Change, 

and Public Land Decision Making, 42 ENVTL. L. 469, 510, 517 

(2012). Thus, OSM’s decision not to complete a social cost of 

carbon analysis because it does not present all the data is flawed 

in a major way as indicated, supra, OSM calculated the 

economic benefits in estimating the modification would provide 

230 jobs, thus only showing one side.

An additional reason that OSM gave for not engaging in a social 

cost of carbon analysis is that the estimates do not include all of 

the important physical, ecological, and economic impacts of 

climate change due to lack of precise data. EA at 79. Of course, 

we do not imply that the impacts of climate change can be fully 

captured by a dollar figure. Droughts, floods, extreme weather 

events, rising sea levels, and other phenomena related to climate 

change present threats to our planet that extend far beyond 

economic harms. Agencies must analyze not only the 

quantitative (and monetizable) climate impacts of proposed 

actions, but the qualitative and nonmonetizable impacts as well. 

Nevertheless, to the extent that a project’s impacts can be 
A-12

Commenter Comment Response

quantified, the social cost of carbon is the best and most rigorous 

tool currently available for understanding the damages linked to 

carbon emissions, rather than simply the extent of the emissions 

themselves. Thus, OSM must at least attempt to quantify the 

costs of its impacts, even with a disclaimer that there could be 

many more impacts that are not quantified.

OSM stated that the Social Cost of Carbon was designed for 

rulemakings and note for project-level analyses. Id. This is false; 

although often utilized in the context of agency rulemakings, the 

protocol has been recommended for use and has been used in 

project-level decisions. For instance, the EPA recommended that 

an EIS prepared by the U.S. Department of State for the 

proposed Keystone XL oil pipeline include “an estimate of the 

‘social cost of carbon’ associated with potential increases of 

GHG emissions.” EPA, Comments on Supplemental Draft EIS 

for the Keystone XL Oil Pipeline (June 6, 2011) (Attached as 

Exhibit 11). Furthermore, although it was initially developed to 

help agencies develop regulatory impact assessments of 

proposed rules, the social cost of carbon need not and should not 

be limited to this application. As CEQ has confirmed, statements 

that a particular agency decision will result in only a small 

fraction of global GHG concentrations should not be used to 

avoid analyzing the impact of those emissions. Consideration of 

Greenhouse Gas Emissions and Climate Change Effects in 

NEPA Reviews, 79 Fed. Reg. at 77,825. Such statements, 

according to CEQ, reflect the nature of climate change rather 

than the impact of any particular project. Id.

NEPA requires OSM to use the social cost of carbon because it 

is the best tool available to analyze the economic and 

environmental impact of increased carbon dioxide emissions. 

NEPA specifically requires federal agencies to analyze and 

disclose the environmental effects of their actions, including 

“ecological . . . aesthetic, historic, cultural, economic [and] 

health” impacts. 40 C.F.R. § 1508.8. Where “information 

relevant to reasonably foreseeable significant adverse impacts 

cannot be obtained because the overall costs of obtaining it are 

exorbitant or the means to obtain it are not known,” NEPA 

regulations direct agencies to evaluate a project’s impacts “based 

upon theoretical approaches or research methods generally 

accepted in the scientific community.” 40 C.F.R. § 

1502.22(b)(4).

Agencies cannot ignore the effects of GHG emissions from 

mining operations or coal combustion. High County Consv. 

Advocates v. US Forest Service, 52 F. Supp. 3d 1174, 1190 

(2014). Nor can they “completely [] ignore a tool in which an 

interagency group of experts invested time and expertise.” Id. at 

1193. NEPA requires agencies to engage in “a reasonable, good 

faith, objective presentation of the topics,” such that it “foster[s] 

both informed decisionmaking and informed public 

participation.” Custer Cnty Action Ass’n v. Garvey, 256 F.3d 

1024, 1035 (10th Cir. 2001) (citations omitted). The social cost 

of carbon is based on generally accepted research methods and 

years of peer-reviewed scientific and economic studies. It was 

developed by experts at a dozen federal agencies and offices, 

and it is both widely used and generally accepted in the scientific 

community. As such, it is the best tool now available for 

agencies to use in predicting and analyzing the climate impacts 

of proposed federal actions.

OSM additionally stated that it would not undertake a social cost 

of carbon analysis because it was “no longer governmental 
A-13

Commenter Comment Response

policy.” EA at 79. While the IWG is no longer collected, 

agencies are still obligated to analyze the costs of GHG 

emissions. Specifically, federal agencies’ obligation to use the 

social cost of carbon to analyze the costs associated with GHG 

emissions through NEPA was directly affirmed by the court in 

High Country. 52 F. Supp. 3d 1174. In his decision, Judge 

Jackson identified the IWG’s social cost of carbon protocol as a 

tool to “quantify a project’s contribution to costs associated with 

global climate change.” Id. at 1190. “The critical importance of 

[climate change] . . . tells me that a ‘hard look’ has to include a 

‘hard look’ at whether this tool, however imprecise it might be, 

would contribute to a more informed assessment of the impacts 

than if it were simply ignored.” Id. at 1193. To fulfill this 

mandate, they agency must use the social cost of carbon to 

disclose the “ecological[,] . . . economic, [and] social” impacts 

of the proposed action. 40 C.F.R. § 1508.8(b).

Importantly, other agencies within the Interior Department, have 

already utilized the social cost of carbon protocol in the context 

of analyzing the impacts of fossil fuel development under 

NEPA. In recent Environmental Assessments for oil and gas 

leasing in Colorado, the BLM estimated “the annual SCC [social 

cost of carbon] associated with potential development on lease 

sale parcels.” BLM, “Environmental Assessment for October 21, 

2014 Oil and Gas Lease Sale,” DOI-BLM-MT-0010-2014-

0011-EA (May 19, 2014) at 76, available at: 

http://www.blm.gov/style/medialib/blm/mt/blm_programs/energ

y/oil_and_gas/leasing/lease_sales/2014/oct__21_2014/july23pos

ting.Par.25990.File.dat/MCFO%20EA%20October%202014%2

0Sale_Post%20with%20Sale%20(1).pdf. In conducting its 

analysis, the BLM used a “3 percent average discount rate and 

year 2020 values,” presuming social costs of carbon to be $46 

per metric ton. Id. Based on its estimate of greenhouse gas 

emissions, the agency estimated total carbon costs to be 

“$38,499 (in 2011 dollars).” Id. In Idaho, the BLM also utilized 

the social cost of carbon protocol to analyze and assess the costs 

of oil and gas leasing. Using a 3% average discount rate and year 

2020 values, the agency estimated the cost of carbon to be $51 

per ton of annual CO2e increase. BLM, “Little Willow Creek 

Protective Oil and Gas Leasing,” EA No. DOI-BLM-ID-B010-

2014-0036-EA (February 10, 2015) at 81 (Attached as Exhibit 

12). Based on this estimate, the agency estimated that the total 

carbon cost of developing 25 wells on five lease parcels to be 

$3,689,442 annually. Id. at 83.

Recently, Michael Greenstone, the former chief economist for 

the President’s Council of Economic Advisers, confirmed that it 

is appropriate and acceptable to calculate the social cost of 

carbon when reviewing whether to approve fossil fuel extraction. 

See Greenstone, M., “There’s a Formula for Deciding When to 

Extract Fossil Fuels,” New York Times (Dec. 1, 2015). To be 

certain, the social cost of carbon protocol presents a conservative 

estimate of economic damages associated with the 

environmental impacts climate change. In fact, more recent 

studies have reported significantly higher carbon costs. For 

instance, a report published in 2015 found that current estimates 

for the social cost of carbon should be increased six times for a 

mid-range value of $220 per ton. Moore, C.F. & Delvane, B.D., 

“Temperature Impacts on Economic Growth Warrant Stringent 

Mitigation Policy,” Nature Climate Change (January 12, 2015) 

at 2 (Attached as Exhibit 13). In spite of uncertainty and likely 

underestimation of carbon costs, nevertheless, the SCC is a 

useful measure to assess the benefits of CO2 reductions, and 
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Commenter Comment Response

costs of not reducing CO2.

That the economic impacts of climate change, as reflected by an 

assessment of social cost of carbon, should be a significant 

consideration in agency decision-making, is emphasized by a 

2014 White House report, which warned that delaying carbon 

reductions would yield significant economic costs. See 

Executive Office of the President of the United States, “The Cost 

of Delaying Action to Stem Climate Change” (July 2014) 

(Attached as Exhibit 14). As the report states: [D]elaying action 

to limit the effects of climate change is costly. Because CO2

accumulates in the atmosphere, delaying action increases CO2

concentrations. Thus, if a policy delay leads to higher ultimate 

CO2 concentrations, that delay produces persistent economic 

damages that arise from higher temperatures and higher CO2

concentrations. Alternatively, if a delayed policy still aims to hit 

a given climate target, such as limiting CO2 concentration to 

given level, then that delay means that the policy, when 

implemented, must be more stringent and thus more costly in 

subsequent years. In either case, delay is costly.

Id. at 1.

The requirement to analyze the social cost of carbon is supported 

by the general requirements of NEPA and supported in federal 

case law. As explained, NEPA requires agencies to analyze the 

consequences of proposed agency actions and consider include 

direct, indirect, and cumulative consequences.

To this end, courts have ordered agencies to assess the social 

cost of carbon pollution, even before a federal protocol for such 

analysis was adopted. In 2008, the U.S. Court of Appeals for the 

Ninth Circuit ordered the National Highway Traffic Safety 

Administration to include a monetized benefit for carbon 

emissions reductions in an Environmental Assessment prepared 

under NEPA. Center for Biological Diversity v. National 

Highway Traffic Safety Administration, 538 F.3d 1172, 1203 

(9th Cir. 2008). The Highway Traffic Safety Administration had 

proposed a rule setting corporate average fuel economy 

standards for light trucks. A number of states and public interest 

groups challenged the rule for, among other things, failing to 

monetize the benefits that would accrue from a decision that led 

to lower carbon dioxide emissions. The Administration had 

monetized the employment and sales impacts of the proposed 

action. Id. at 1199. The agency argued, however, that valuing the 

costs of carbon emissions was too uncertain. Id. at 1200. The 

court found this argument to be arbitrary and capricious. Id. The 

court noted that while estimates of the value of carbon emissions 

reductions occupied a wide range of values, the correct value 

was certainly not zero. Id. It further noted that other benefits, 

while also uncertain, were monetized by the agency. Id. at 1202.

More recently, a federal court has done likewise for a federally 

approved coal lease. That court began its analysis by recognizing 

that a monetary cost-benefit analysis is not universally required 

by NEPA. See, 52 F.Supp.3d 1174, citing 40 C.F.R. § 1502.23. 

However, when an agency prepares a cost-benefit analysis, “it 

cannot be misleading.” Id. at 1182 (citations omitted). In that 

case, the NEPA analysis included a quantification of benefits of 

the project. However, the quantification of the social cost of 

carbon, although included in earlier analyses, was omitted in the 

final NEPA analysis. Id. at 1196. The agencies then relied on the 

stated benefits of the project to justify project approval. This, the

court explained, was arbitrary and capricious. Id. Such approval 

was based on a NEPA analysis with misleading economic 
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Commenter Comment Response

assumptions, an approach long disallowed by courts throughout 

the country. Id. Recently, a federal district court in Montana 

reaffirmed the reasoning in High Country, indicating that a 

NEPA analysis that included the economic benefits of a project 

was incomplete without an assessment of the carbon costs that 

would result from the development. Mont. Envtl. Info. Ctr., CV 

15-106-M-DWM. In agreeing with the Plaintiffs, the Court 

specifically mentioned the Social Cost of Carbon Protocol as one 

tool to use to quantify the costs associated with the mine 

expansion. Id. at 35. Further, a D.C. Circuit Court ruled that an 

agency’s assessment of the environmental impact of pipelines 

was inadequate, reasoning that it did not contain enough 

information on the greenhouse-gas emissions resulting from 

burning the gas that the pipelines carry. Sierra Club, et al., v. 

Federal Energy Regulatory Commission, No. 16-1329 (D.C. Cir. 

Aug. 22, 2017) (Attached as Exhibit 15). Thus, the most recent 

rulings indicate a robust analysis of GHG is necessary.

Using any of the Interagency Working Group’s social cost of 

carbon values demonstrates that the combustion of coal from the 

proposed expansion will likely result in massive economic 

damages associated with climate change. The total climate 

impacts from the proposal will reach into the hundreds of 

millions of dollars, and this must be disclosed to the public and 

decision makers.

To this end, OSM must fully analyze and disclose the carbon 

costs of authorizing the proposed mining plan modification.”

WildEarth “OSM must analyze and assess the impacts of similar and An EIS was completed by OSMRE for the 

Guardians cumulative mining and coal leasing approvals that are under San Juan Mine and San Juan Generating 

consideration by the U.S. Department of the Interior in the same Station because the Proposed Action at the 

area. Under NEPA, an agency must analyze the impacts of mine would necessitate changes to the 

“similar” and “cumulative” actions in the same NEPA document operation of the power plant meaning the 

in order to adequately disclose impacts in an EIS or provide power plant had to be considered as a 

sufficient justification for a FONSI in an EA. See 40 C.F.R. §§ connected action under NEPA. This is not 

1508.25(a)(2) and (3). Similar actions include actions that, true for the Jim Bridger Mine and Jim 

“when viewed with other reasonably foreseeable or proposed Bridger Power Plant. Analysis of potential 

agency actions, have similarities that provide a basis for impacts from mining and combusting 

evaluating their environmental consequences together.” 40 Proposed Action coal was completed for all 

C.F.R. § 1508.25(a)(3). Key indicators of similarities between resources listed in Table 3-1in the EA. The 

actions include “common timing or geography.” Id. analysis concluded that there would be no 

significant impacts to any of the identified 

resources. Impact intensity is described in 

Section 4.1 of the EA. Section 4.2.1.1.2 of 

the EA disclose the potential direct and 

indirect impacts of greenhouse gas emissions 

on the environment. OSMRE concluded that 

impacts of GHGs would be short-term and 

minor.

Cumulative impacts resulting from the 

The significance of these impacts is based on the “context” and 

“intensity” of the impacts. 40 C.F.R. § 1508.27. Context of the 

impacts is determined by the impacts to, among other factors,

the affected region, locality, whether the action “affects public 

health or safety,” the “[u]nique characteristics of the geographic 

area,” the degree to which impacts are likely to be “highly

controversial” or “highly uncertain,” and whether the action may

be cumulatively significant. 40 C.F.R. § 1508.27(b). An agency

may prepare an environmental assessment (“EA”) to analyze the 

effects of its actions and assess their significance. See 40 C.F.R. Proposed Action are disclosed in Section 

§ 1508.9; see also 43 C.F.R. § 46.300. 5.2.3 of the EA.

We are primarily concerned by the potentially significant The projects provided in the comment do not 

cumulative impacts posed by nearby coal mines and associated fall into the geographical scope of the 

power plants in the area. Sweetwater county is home to the Jim cumulative impacts analysis area for the 

Bridger Power Plant, the Jim Bridger Coal Mine, as well as the Proposed Action; therefore, they are not 

Black Butte Coal Mine. Here, the U.S. Department of the included in the cumulative impacts analysis 

Interior is currently weighing numerous coal decisions, similar in the EA.

to the proposed action at hand, which pose similar and 

cumulative impacts in terms of greenhouse gas emissions, 

climate, and other impacts, particularly in terms of carbon costs. 

In fact, PacifiCorp recently submitted a new application for a 

Section 4.2.1.1.2 of the EA has been revised 

to compare GHG emissions from the 

Proposed Action to GHG emissions in the 

State of Wyoming, GHG emissions in the 
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Commenter Comment Response

federal coal lease to expand the Jim Bridger Coal Mine. This 

lease application, which has been assigned serial number WYW185637, would add 1,721 acres and 19.8 million tons of coal to 

the mine (Attached as Exhibit 16). Furthermore, PacifiCorp 

recently applied for a new coal exploration license, indicating 

the possibility of even more mining. Fed. Reg. 18505 September 

1, 2017. Additionally, more coal mining was also just approved 

at Black Butte mine, which also contributes fuel to the Jim 

Bridger power plant

(Attached as Exhibit 17).

OSM cannot justify a FONSI unless and until it fully accounts 

for the cumulative impacts of past, present, and reasonably 

foreseeable mining at the Jim Bridger mine and the nearby Black 

Butte mine. An EIS must fully analyze and assess these impacts.

Further, an EIS must fully analyze and assess the impacts of 

similar federal coal leasing and mining approvals being 

undertaken throughout the region in order to properly account 

for the climate impacts of mining and the reasonably foreseeable 

impacts of coal combustion. This is especially necessary given 

that OSM acknowledges that when it comes to greenhouse gas 

emissions, emissions at both a national and statewide scale are 

relevant for analyzing and assessing impacts. See EA at 41 

(disclosing national greenhouse gas emissions from fossil fuel 

combustion and coal mining, as well as state-wide energyrelated carbon dioxide emissions). As the agency explicitly 

states, the analysis area for consideration of climate impacts 

includes the states of Montana, Wyoming, North Dakota, South 

Dakota, Nebraska, Kansas, Oklahoma, and Texas. Id. at 29. This 

is due to the fact that, as OSM acknowledges, “climate change 

and global warming are regional and global phenomena.” Id.

In addition to past, present, and future mining proposals, the 

U.S. Department of the Interior and its agencies, including OSM 

and BLM, are presently considering numerous new coal leasing 

proposals and mining plans. These proposals are being 

undertaken in the same region, i.e., the western United States, 

and all under the oversight of the U.S. Department of the 

Interior. These proposals include, but are not limited to:

• The BLM’s proposal to offer for sale and issuance the Spring 

Creek II coal lease (MTM-105485), a 198-million-ton coal lease 

containing 1,602 acres in the Powder River Basin of Montana. 

The lease is currently under review by the BLM and was applied 

for in 2013.2

• The BLM’s proposal to issue a lease modification to expand 

the nearby Black Butte coal mine, which also fuels the Jim 

Bridger power plant. The lease modification would add 450 

acres to the Black butte mine.

• OSMRE’s proposal to approve mining plan modifications for 

the Spring Creek coal mine in the Powder River Basin of 

southeastern Montana. OSMRE is currently reviewing whether 

to approve the Spring Creek TR1 modification, which would add 

48.1million tons of coal to the mine.

• Cordero Rojo in Wyoming, a mining plan modification 

(WYW174407), adding 569.1 acres, amounting 55.7 million 

tons of coal, extending the life of the mine by three years.

• West Antelope III in Wyoming, a lease by application 

(WYW184599) for 3,508 acres, totaling 441M tons of coal.

• King II Mine in Colorado, a lease modification (COC62920) 

for 950 acres, totaling 6.3M tons of coal.

climate change impacts analysis area, and 

GHG emissions in the U.S. The climate 

change impacts analysis area, described in 

Section 3.3 of the EA, is the Great Plains 

region (Montana, Wyoming, North Dakota, 

South Dakota, Nebraska, Kansas, Oklahoma, 

and Texas).
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Commenter Comment Response

• West Elk Mine in Colorado, a lease modification (COC1362 & 

COC67232), for 800 and 920 acres, totaling 10.1M tons of coal.

These are just a handful of the coal decisions pending before 

Interior that pose potentially significant climate impacts. Given 

past approvals, the cumulative impacts could be even more 

significant. It is imperative that OSM analyze the impacts of 

mining at the Bridger Mine consistent with the scope required 

under NEPA in order to ensure that impacts of cumulative and 

similar are fully analyzed and assessed consistent with 40 C.F.R. 

§ 1508.25(a).

Moreover, due to the checkerboard nature of the federal lease 

ownership in that region, this modification of the mining plan 

would represent not only an increase of potential coal in the 

future of a stated 4.5 million tons, but potentially a full 

development of the tract.

Additionally, OSM must analyze and assess the entire Jim 

Bridger Complex, including the power plant and the coal mine. 

Federal coal lease WYW-02727 was originally issued in 1969 

and has grown to 14,279 acres. The additional expansions have 

never been assessed alongside the impacts stemming from the 

combustion of the additional coal that has been mined. The 

Bridger Mine complex (including both the surface and 

underground mining operations) and the Jim Bridger Power 

Plant are interdependent, connected operations. Jim Bridger 

mine is a major supplier of coal to the Jim Bridger Power Plant. 

OSM did not consider the impacts of additional CO2, methane, 

and other emissions from both the mining and the combustion of 

the coal.”

WildEarth 

Guardians

“We requested the OSM consider in detail an alternative that 

limits the amount of coal tonnage and/or acreage to be mined to 

lower levels than are currently proposed. OSM stated that this 

alternative was not considered in detail because it would not 

meet the purpose and need and would be inconsistent with the 

MLA requirement to maximize recovery by achieving maximum 

economic recovery under 43 CFR 3480.0-5(21). EA at 25.

The general purpose of coal mining under SMCRA is to meet 

the Nation’s energy needs. OSM may meet these goals by 

promoting renewable energy and energy conservation. Courts 

have long interpreted the mandate to consider reasonable 

alternatives to require agencies contemplating energy projects to 

consider reasonable alternative forms of energy generation and 

energy conservation. NRDC v. Morton, 458 F.2d 827, 833-38 

(D.C. Cir. 1972); Hodel, 865 F.2d at 295-97 (agency required to 

consider conservation alternatives in analysis of decision to issue 

oil and gas leases); Libby Rod & Gun Club v. Poteat, 457 F. 

Supp. 1177, 1186-8 (D. Mont. 1978), aff’d in part and rev’d in 

part on other grounds, 59 F.2d 742 (9th Cir. 1979). This 

consideration may include lower alternative mining levels.

OSM’s authority does not provide it a mandatory duty to 

approve coal leasing, but rather, it conveys full discretion upon 

the agency to reject coal leasing. As the courts have noted, 

Congress intended the MLA: “to provide for a more orderly 

procedure for the leasing and development” of coal the United 

States owns, while ensuring its development “in a manner 

compatible with the public interest.” Northern Cheyenne Tribe 

v. Hodel, 851 F.2d 1152, 1156 (9th Cir. 1988) (citation omitted).

Further, maximum economic recovery under 43 CFR 3480.0-

5(21) may be based on economically feasible equipment, and 

coal marketability. With the implementation of emissionsOSMRE’s purpose and need for the federal 

action includes the need to provide BCC the 

opportunity to exercise its valid existing 

rights granted by the BLM under federal coal 

lease WYW-02727 to access and mine 

undeveloped resources located adjacent to the 

existing mining operations at the Bridger 

Mine Complex. Chapter 1 of the EA explains 

OSMRE’s purpose and need and OSMRE’s 

decision-making authority. OSMRE has 

determined, through the analysis in the EA, 

that the proposed mining plan modification 

meets this purpose and need without 

significantly affecting the human 

environment. While promoting alternative 

forms of energy generation and energy 

conservation are approaches to meeting the 

Nation’s energy needs, the decision to be 

made by OSMRE in this instance is whether 

to recommend disapproval, approval, or 

approval with conditions of a proposed 

mining plan modification to the Assistant 

Secretary of Land and Minerals Management.

No change required.
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Commenter Comment Response

reducing retrofits, the recovery of this particular coal may 

become economically infeasible. Moreover, coal markets have 

been shown to be in decline.”

WildEarth 

Guardians

“We requested that, in order to limit air quality impacts, that 

OSM consider in detail an alternative that requires the use of 

equipment that produce less or no emissions, such as natural gasfired vehicles and machinery and electric machinery powered by 

solar panels or other renewable energy sources. OSM stated that 

the cost to make the switch would be prohibitive for the minimal 

benefit to the regional air quality. EA at 26.

The assumption that a retrofitting of equipment will not reduce 

emissions is flawed. Mining at Jim Bridger occurs 24 hours a 

day, and runs equipment which emits pollution 24 hours a day. It 

is senseless that OSM would simply deny the possibility that 

pursuing less pollutant-emitting non-diesel equipment would not 

affect or reduce emissions, without explaining the threshold of 

what “limited effect on regional air emissions” would amount 

to.”

As stated in Section 2.2.3.2 of the EA, 

Alternatives Considered But Not Carried 

Forward, the Bridger Mine Complex uses 

electric draglines and diesel powered mobile 

equipment. Mining operations at the Bridger 

Mine Complex are a relatively small 

contributor to the emissions related to engine 

combustion in the region, so switching to 

equipment powered by a different fuel would 

be cost prohibitive, considering the minimal 

benefit to regional air quality.

No change required.

WildEarth 

Guardians

“We requested that OSM consider air quality mitigation of the 

proposed mining. OSM responded by stating that mitigation 

measures imposing more stringent emission limits were beyond 

its authority. EA at 26. This is flawed; OSM is required to 

consider alternatives that are not within its jurisdiction under 40 

C.F.R. § 1502.14(c). OSM may evaluate state regulated mining 

activities on federal lands.”

Section 2.2.3.5 provides OSMRE’s rationale 

for dismissing an air quality mitigation 

alternative. 

Section 4.2.1.1.2 of the EA discloses 

potential direct and indirect impacts to air 

quality - Because the Proposed Action would 

be a continuation of mining and would occur 

under the Bridger Mine Complex’s existing 

air permits and because of the particulate 

monitoring system and contingency action 

plan, direct emission impacts from mining 

activities under the Proposed Action are 

expected to be short-term (extended for 13 

years) and minor.

There would be no resulting change in 

overall Bridger Mine Complex annual coal 

production and delivery to the Jim Bridger 

Power Plant, and no change to the Jim 

Bridger Power Plant’s production rate. 

Indirect impacts from the burning of federal 

coal from the project area are expected to be 

short-term and minor.

No change required.

WildEarth 

Guardians

“We requested that OSM consider mitigation of greenhouse gas 

emissions associated with the proposed mining. OSM rejected 

exploring this alternative because they stated they did not have 

the regulatory authority to require electricity-generating plants to 

reduce emissions because the emissions are regulated by the 

States or Counties where the plants are located.

Generally, SMCRA explicitly requires that surface coal mining 

operations, including the surface impacts of underground 

mining, be conducted so as “to protect the environment.” 30 

U.S.C. § 1202(d). SMCRA does not delegate authority for states 

to review and take action on mining plans and does not allow 

Interior and OSM to relinquish their duty to make independent 

findings regarding SMCRA compliance when taking action on 

mining plans. While SMCRA may delegate authority to states to 

regulate coal mining on federal lands, such delegation does not 

strip the authority of Interior and OSM to find that state 

regulation is inadequate. Here, OSM may therefore consider 

This alternative would limit or reduce 

greenhouse gas (GHG) emissions associated 

with the proposed mining activities by 

requiring BCC to secure an increase in the 

efficiency of the power plants it fuels to 

reduce the total CO2 rate, requiring the use of 

low-carbon fuels for the operation of heavy 

machinery, and/or requiring BCC to use 

renewable energy to power the Bridger Mine 

Complex. This alternative was eliminated 

from detailed analysis because OSMRE does 

not have the regulatory authority to require 

electricity-generating plants to reduce 

emissions because the emissions are 

regulated by the States or Counties where the 

plants are located. Any mitigation measure 

proposed by OSMRE imposing more 

stringent emission limits at generating 
A-19

Commenter Comment Response

alternatives in the context of whether that regulation would be 

adequate under the cooperative federalism scheme.”

stations and upon oil and gas operators is 

beyond OSMRE’s authority and its 

implementation would be highly remote and 

speculative. Impact intensity is described in 

Section 4.1of the EA. Section 4.2.1.1.2 and 

Section 5.2.1.3 of the EA disclose the 

potential direct and indirect impacts of 

greenhouse gas emissions on the 

environment. OSMRE concluded that 

impacts of GHGs would be short-term and 

minor; therefore, mitigation of GHGs was not 

analyzed in the EA.

No change required.

WildEarth 

Guardians

“In our earlier comments, we stated that offsite mitigation, as 

well as mitigation that requires compensation, is explicitly 

authorized under NEPA. OSM stated that because no significant 

impacts are predicted from CO2 emissions attributed to the 

Proposed Action, an alternative that requires compensatory 

mitigation is eliminated from detailed analysis. EA at 27.

Here, the EA did not fully analyze the significant impacts of 

leasing and mining the lease. The EA failed to address a number 

of potentially significant impacts, including the climate impacts 

related to the reasonably foreseeable consequence of coal 

combustion, and cumulative impacts related to additional federal 

coal management decisions, including additional leasing that had 

occurred since the original lease was granted. Put another way, 

the EA is insufficient to analyze these impacts, as only an EIS 

can be utilized to analyze and assess significant environmental 

impacts under NEPA. See 40 C.F.R. § 1502.3. Thus, OSM 

cannot possibly determine whether or not the impacts of 

emissions are significant, because its EA analysis was woefully 

insufficient. Therefore, it also cannot say whether it would not 

consider this particular alternative.”

Section 4.2.1.1.2 of the EA discloses the 

potential direct and indirect impacts of 

greenhouse gas emissions on the 

environment. OSMRE concluded that 

impacts of GHGs would be short-term and 

minor; therefore, mitigation of GHGs was 

determined to unnecessary and not analyzed 

in the EA.

No change required.
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