United States Department of the Interior

Office of Surface Mining Reclamation and Enforcement

Environmental Assessment 

Caballo Mine

Campbell County, Wyoming 

Mining Plan

for

Federal Coal Lease WYW172657

August 2019

Prepared by:

U.S. Department of the Interior

Office of Surface Mining Reclamation and Enforcement Program Support Division 

1999 Broadway, Suite 3320

Denver, CO 80202

PH: 303-293-5000 / FAX: 303-293-5032

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 i

TABLE OF CONTENTS

1.0 Purpose and Need ....................................................................................................1-1

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

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

1.3 Purpose and Need ........................................................................................................................1-6

1.4 Regulatory Framework and Necessary Authorizations........................................................1-6

1.5 Outreach and Issues.....................................................................................................................1-6

1.6 Crosswalk of Resource Areas....................................................................................................1-7

1.7 Public Involvement........................................................................................................................1-7

2.0 Proposed Action and Alternatives .....................................................................2-1

2.1 Description of Alternatives.........................................................................................................2-1

2.2 Existing Conditions (Conditions Common to the Proposed Action and the No 

Action Alternative).......................................................................................................................2-4

3.0 Affected Environment..........................................................................................3-1

3.1 General Setting ..............................................................................................................................3-1

3.2 Topography and Physiography ...................................................................................................3-1

3.3 Geology, Mineral Resources, and Paleontology .....................................................................3-1

3.4 Air Quality and Climate Change................................................................................................3-2

3.5 Water Resources........................................................................................................................3-10

3.6 Alluvial Valley Floors ..................................................................................................................3-16

3.7 Wetlands.......................................................................................................................................3-16

3.8 Soils................................................................................................................................................3-16

3.9 Vegetation.....................................................................................................................................3-16

3.10 Wildlife ..........................................................................................................................................3-18

3.11 Land Use and Recreation ..........................................................................................................3-21

3.12 Cultural Resources.....................................................................................................................3-21

3.13 Visual Resources..........................................................................................................................3-22

3.14 Noise..............................................................................................................................................3-22

3.15 Transportation.............................................................................................................................3-22

3.16 Hazardous and Solid Waste......................................................................................................3-22

3.17 Socioeconomics...........................................................................................................................3-22

4.0 Environmental Consequences/Cumulative Impacts.........................................4-1

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

4.2 Topography and Physiography....................................................................................................4-2
ii Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

TABLE OF CONTENTS (Continued)

4.3 Geology, Mineral Resources, and Paleontology......................................................................4-3

4.4 Air Quality and Climate Change................................................................................................4-4

4.5 Water Resources........................................................................................................................4-15

4.6 Alluvial Valley Floors ..................................................................................................................4-24

4.7 Wetlands/Aquatic Features.......................................................................................................4-24

4.8 Soil ..................................................................................................................................................4-25

4.9 Vegetation.....................................................................................................................................4-26

4.10 Wildlife ..........................................................................................................................................4-26

4.11 Land Use and Recreation...........................................................................................................4-29

4.12 Cultural Resources.....................................................................................................................4-30

4.13 Visual Resources..........................................................................................................................4-31

4.14 Noise..............................................................................................................................................4-31

4.15 Transportation Facilities............................................................................................................4-32

4.16 Hazardous and Solid Waste......................................................................................................4-33

4.17 Socioeconomics...........................................................................................................................4-34

4.18 Short-Term Uses and Long-Term Productivity....................................................................4-36

4.19 Unavoidable Adverse Effects.....................................................................................................4-36

5.0 Consultation and Coordination ..........................................................................5-1

5.1 Public Comment Process............................................................................................................5-1

5.2 Preparers and Contributors.......................................................................................................5-1

5.3 Distribution of the EA..................................................................................................................5-1

6.0 References .................................................................................................................6-1

LIST OF TABLES

Table 1-1. Crosswalk of Resources Analyzed in the SGAC EIS and This EA.............................1-8

Table 2-1. Comparison of Coal Production, Surface Disturbance, Mine Life, and

Employees for the No Action Alternative and Proposed Action .............................2-1

Table 2-2. Summary of Phased Bond Release Acreages in the Project Area .............................2-6

Table 3-1. Average Annual and Maximum 24-hr PM10 Concentrations (μg/m3

) forthe

Caballo Mine..........................................................................................................................3-2

Table 3-2. Measured PM2.5 Concentrations in Campbell County .................................................3-4

Table 3-3. Estimated Average Annual and Maximum 24-hr PM2.5 Concentrations

(μg/m3

) for the Caballo Mine.............................................................................................3-4

Table 3-4. Measured NO2 Concentrations (ppb) in Campbell County .......................................3-6
Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 iii

TABLE OF CONTENTS (Continued)

Table 3-5. Measured O3 Concentrations (ppm) in Campbell County .........................................3-6

Table 3-6. Measured SO2 Concentrations (μg/m3

) in Campbell County ....................................3-6

Table 3-7. Measured Annual Pb Air Emissions from Three Campbell County Power

Stations and One Campbell County Coal Mine ............................................................3-6

Table 3-8. Measured Annual Hg Stack (Air) Emissions from Power Stations in

Campbell County (Pounds)................................................................................................3-7

Table 3-9. Estimated Annual PM10, PM2.5, SO2, NOX, and Hg Contributions (tons) from

Caballo Mine Coal Combustion........................................................................................3-8

Table 3-10. Measured Hydrogen Ion (H+) Concentrations at Monitoring Site WY99 .............3-9

Table 3-11. Estimated Caballo Mine Direct and Indirect CO2e Emissions at the Caballo

Mine from Coal Combustion...........................................................................................3-10

Table 3-12. Recent and Historical TDS Concentrations from the Caballo Mine

Groundwater Monitoring Network...............................................................................3-13

Table 3-13. Campbell County and City of Gillette Population Change, 2010-2017.................3-23

Table 3-14. Wyoming and Campbell County Employment Rate Change, 2011-2017..............3-23

Table 4-1. Comparison of Direct to Wyoming Particulate Matter Emissions...........................4-4

Table 4-2. PM10 Concentration Values (24-Hr, First Maximum Value - μg/m3

) for

2010-2017 ..............................................................................................................................4-5

Table 4-3. McVehil-Monnett and Redhorse Annual PM10 and NO2 Dispersion

Modeling Results ..................................................................................................................4-6

Table 4-4. Comparison of Direct to Wyoming NOx Emissions ...................................................4-7

Table 4-5. Comparison of Direct to Wyoming SO2, Hg, Pb and Other Non-GHG

Emissions................................................................................................................................4-9

Table 4-6. Estimated Annual PM10, PM2.5, SO2, NOX, and Hg Contributions from

Combustion of Coal Mined at the Caballo Mine for 2013-2017 and 2018-

2051, Compared to Campbell County and U.S. Total Emissions ...........................4-10

Table 4-7. Average Annual Campbell County Air Quality Index Values...................................4-11

Table 4.8. Estimated Annual Average 2013-2017 and 2018-2051 Direct and Indirect

CO2e Emissions at the Caballo Mine.............................................................................4-12

Table 4-9. LOM Federal and State Revenues from Federal Coal Recovery within the

Caballo Mine (millions of dollars)...................................................................................4-34

Table 4-10. LOM Federal and State Revenues from Federal Coal Recovery within the

Caballo West Tract (millions of dollars).......................................................................4-35

Table 4-11. Unavoidable Adverse Effects of the Proposed Action...............................................4-37

Table 5-1. OSMRE Personnel................................................................................................................5-1

Table 5-2. Third Party Contractor Personnel...................................................................................5-1
iv Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

TABLE OF CONTENTS (Continued)

LIST OF FIGURES

Figure 3-1. Visibility in the Wind Cave National Park ......................................................................3-8

LIST OF MAPS

Map 1-1. General Location Map with Federal Coal Leases..........................................................1-2

Map 1-2. Caballo Mine’s Federal Coal Leases.................................................................................1-3

Map 3-1. Wind Rose and Air Quality and Meteorological Monitoring Stations at the

Caballo Mine and Surrounding Mines..............................................................................3-3

Map 3-2. Regional Air Quality Monitoring Sites.............................................................................3-5

Map 3-3. Active Groundwater Monitoring Locations and Water Supply Wells at the

Caballo Mine........................................................................................................................3-12

Map 3-4. Surface Water Monitoring Sites at the Caballo Mine ................................................3-15

Map 3-5. Wetlands within and Surrounding the Caballo West Tract.....................................3-17

Map 3-6. Raptor Nest Sites and Greater Sage-grouse Leks within and Adjacent to

the Caballo West Tract....................................................................................................3-19

Map 4-1. Modeled Drawdown for the Wyodak Coal Seam......................................................4-17

Map 4-2. Cumulative Impact Area for Potential Surface Water and Groundwater 

Impacts..................................................................................................................................4-19

LIST OF APPENDICS

Appendix A Legal Notices for Federal Coal Lease Modification Approval WYW172657

Appendix B Public Scoping and Notice of Availability Mailing Lists and Public Scoping 

Comment Summaries and EA Review Comment Summaries and Responses 

(Individual Letters Received Have Not Been Included)

Appendix C Greenhouse Gas Emissions Calculations, PM10, PM2.5, SO2, NOx, Hg, CO, and 

CO2 Contributions from Coal Combustion Calculations (Completed by WWC 

Engineering)

Appendix D Revenue Calculations (Completed by WWC Engineering)

Appendix E Caballo Mine Special Status Species Summary Tables for Federal Lease 

Modification Approval – WYW172657

Appendix F Climate Change Discussion
Chapter 1- Purpose and Need

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 1-1

1.0 Purpose and Need

1.1 Introduction

This Environmental Assessment (EA) for the Caballo Mine Federal Mining Plan Modification for 

Federal Coal Lease WYW172657 (Caballo West tract) has been prepared by the U.S. 

Department of the Interior (DOI) Office of Surface Mining Reclamation and Enforcement 

(OSMRE), Western Region. OSMRE is the lead federal agency responsible for development of 

this EA because, under the Surface Mining Control and Reclamation Act of 1977 (SMCRA) and 

Mineral Leasing Act (MLA), OSMRE will prepare a mining plan decision document (MPDD) in 

support of its recommendation to the Assistant Secretary, Lands and Minerals Management 

(ASLM) regarding federal mining plan modifications (OSMRE 1999). The ASLM will decide 

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

Using criteria outlined in OSMRE’s Handbook for Implementing the National Environmental 

Policy Act (NEPA) (OSMRE 1989), the DOI’s Departmental Manual (DM) Part 516 (DOI 2004), 

and the Council on Environmental Quality (CEQ) Regulations for Implementing the Procedural 

Provisions of NEPA (40 Code of Federal Regulation [CFR] 1500-1508), OSMRE determinedthat 

this EA could incorporate by reference analyses included in the 2009 South Gillette Area Coal 

Lease Applications Final Environmental Impact Statement (hereafter 2009 SGAC EIS [BLM 2009]) 

prepared by the Bureau of Land Management (BLM) because the EIS included the Caballo West 

tract as part of its analysis. This approach is consistent with Secretarial Order 3355, which is 

intended to streamline the NEPA process.

This EA review has been conducted in accordance with the NEPA and the CEQ regulations for 

implementing NEPA (40 CFR 1500-1508); the DOI’s regulations for implementation of NEPA (43 

CFR Part 46); the DOI’s Departmental Manual Part 516; Secretarial Order 3355; and OSMRE’s 

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

Act of 1969 (OSMRE 1989). Information gathered from federal, state, and local agencies, Peabody 

Caballo Mining, LLC (PCM), publicly available literature, and in-house OSMRE sources, such as 

the Caballo Mine Permit Application Package (PAP), was used in the preparation of this EA.

1.2 Background

1.2.1 Site History

The Caballo Mine is operated by PCM, a subsidiary of Peabody Energy Corporation The mine is 

located in Campbell County, Wyoming, approximately 10 miles south-southeast of Gillette (map

1-1). According to information provided by PCM, the Caballo Mine is currently authorized to

recover coal under four distinct federal coal leases, state leases, and various private coal leases, as 

indicated below. The federal leases are shown on map 1-2.

1. Federal Coal Lease WYW3397

2. Federal Coal Lease WYW78633

3. Federal Coal Lease WYW83394

4. Federal Coal Lease WYW122586

5. State Lease (various)

6. Private Coal Lease (various)
1-2 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

Chapter 1- Purpose and Need

Map 1-1. General Location Map with Federal Coal Leases
Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 1-3

Chapter 1- Purpose and Need

Map 1-2. Caballo Mine’s Federal Coal Leases
1-4 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

Chapter 1- Purpose and Need

The Caballo Mine is currently seeking approval from the ASLM to recover coal associated with 

Federal Coal Lease WYW172657, which was leased to Alpha Wyoming Land Company on August 

17, 2011. The lease was subsequently transferred from Alpha Wyoming Land Company to BTU 

Western Resources, which is a subsidiary of Peabody Energy Corporation.

The Caballo Mine is located in the middle of the Wyoming Powder River Basin (PRB), a coal basin 

that spans from northeast Wyoming to southeast Montana. In 2017, Campbell County produced 

approximately 77 percent of the coal mined from federal government-owned coal leases in the

U.S. (DOI Natural Resources Revenue Data 2019). The region also has been heavily developed 

for oil and gas recovery, including coal bed natural gas (CBNG). The Caballo West tract is 

bordered on the north, east, and south by leased federal coal and some privately-owned coal. 

The area to the west of the Caballo West tract includes unleased federal coal. The southwest 

portion of the Caballo Mine permit area overlaps with the Belle Ayr Mine permit area. The Bishop 

Road (Campbell County Road 12) currently runs through a portion of the Caballo West tract 

(map 1-2).

Coal at the Caballo Mine is mined using conventional surface mining methods and shipped from 

an onsite railroad loading facility to electric utilities and industrial customers in the U.S. In 2018, 

100 percent of coal from the Caballo Mine was shipped to U.S. markets. Based on existing federal 

coal leases, mining operations (mining, processing, and shipping coal) could continue at the 

Caballo Mine through approximately 2042.

PCM operates the Caballo Mine under WDEQ-LQD Permit No. 433 in accordance with the 

approved Wyoming State Coal Regulatory Program (30 CFR Part 950). The currently approved 

permit boundary includes the entire Caballo West tract. WDEQ-LQD approved the most recent 

version of Permit No. 433 with the condition that PCM may not mine coal from any federal coal 

lease prior to receiving approval from the ASLM. Although WDEQ-LQD permits are issued based 

on the life-of-mine (LOM) plans for the mining operation, under the Wyoming Environmental 

Quality Act of 1973 (WEQA), permits must be renewed every 5 years (Wyoming Statute [W.S.].

§ 35-11-405 (c)). This EA considers potential effects from mining the Caballo West tract and does 

not reevaluate existing federal mining areas and operation, except for cumulative effects.

The Resource Recovery and Protection Plan (R2P2) for the Caballo Mine breaks the resource 

into nine different areas. The BLM Casper Field Office approved the R2P2 for the Caballo Mine 

in April 2018. This area breakdown is necessary to ensure proper blending of the coal to meet 

coal contract stipulations. It is also necessary to lessen the risk of interrupted coal delivery in 

case an emergency (e.g., pit flooding) disrupts operations in one of the pits. The mine also has 

specific bench lengths and bench orientations. These specific pit lengths, orientations, and other 

mine design factors are necessary to optimize the coal haul distances and to improve coal drying 

at the benches. This mine design has been approved by the BLM in the R2P2 and is needed to 

ensure maximum recovery of the coal resource. As explained in the R2P2, interruptions to the 

mine plan sequence will disrupt these strategic decisions, resulting in illogical sequences, more 

overburden rehandle, longer haul distance, delayed reclamation, and lower coal recovery.

1.2.2 Project Background

In anticipation of needed additional coal reserves, PCM filed an application with BLM on March 15, 

2006 to lease federal coal reserves in a tract southwest of and immediately adjacent to the Caballo 

Mine, under leasing by application regulations (also known as LBA regulations) at 43 CFR § 3425.1 

and the provisions of the Energy Policy Act of 2005 (Public Law No. 109-58). The lease request 

area, which was referred to as the Caballo West tract, was assigned case file number 

WYW172657. PCM applied for the federal coal reserves as a maintenance tract for the Caballo
Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 1-5

Chapter 1- Purpose and Need

Mine. The Caballo West tract and associated federal coal, as approved for lease by the BLM in 

relation to the Caballo Mine are shown on map 1-2.

PCM submitted the Southwest Amendment PAP to the WDEQ-LQD for Permit No. 433 to 

include the Caballo West tract (PCM 2014). The PAP included modifications to include coal from 

lease WYW172657. WDEQ-LQD determined PCM’s application to be administratively complete 

on March 19, 2014 and approved the PAP on November 30, 2015 (WDEQ-LQD 2015a). The 

approved permit contains a condition that the PCM may not mine coal from any federal coal lease 

prior to receiving approval from the ASLM.

PCM also submitted a federal mining plan modification request to OSMRE for federal coal related 

to lease WYW172657. Using criteria outlined in OSMRE’s NEPA Handbook, OSMRE determined 

that an EA that incorporates by reference the 2009 SGAC EIS will fulfill OSMRE’s responsibilities 

under NEPA for evaluating potential impacts resulting from mining the Caballo West tract.

1.2.3 Statutory and Regulatory Background

For existing, approved federal mining plans that are proposed to be modified, pursuant to 30 CFR 

Part 746, OSMRE prepares a federal MPDD for a federal mining plan modification. The MPDD 

recommends approval, disapproval, or approval with conditions of a federal mining plan 

modification (OSMRE 1999). The ASLM reviews the MPDD and decides whether or not to 

approve the federal mining plan modification, and if approved, what, if any, conditions may be 

needed. Under 30 CFR § 746.13, OSMRE will prepare and submit a recommendation regarding 

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

1. the PAP,

2. the 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 (EOs) 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 

BLM with respect to lease WYW172657, the R2P2, and MLA,

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

amendment application and the Wyoming State program, and

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

requirements of 30 CFR Chapter VII, Subchapter D (30 CFR Parts 740 to 746).

In compliance with other federal laws, regulations and EOs, OSMRE also conducts consultation 

with other agencies before it makes its recommendation to the ASLM. This consultation includes 

the U.S. Fish and Wildlife Service (USFWS) Section 7 consultation for threatened and endangered 

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

1973 (ESA) and Section 106 consultation under the National Historic Preservation Act (NHPA).

OSMRE will not reevaluate all potential impacts previously analyzed as part of the 2009 SGAC 

EIS, which included analysis of all federal coal lands identified in the proposed mining plan 

modification. Rather, this EA considers potential changes to the extent or nature of those impacts 

based on information include in Permit No. 433 and new information specific to this action.
1-6 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

Chapter 1- Purpose and Need

1.3 Purpose and Need

As described in 40 CFR § 1502.13, the purpose and need statements briefly specify the purpose 

and need to which the agency is responding in proposing the alternatives including theProposed 

Action.

1.3.1 Purpose

The purpose of the action is established by the MLA and SMCRA, which require the evaluation 

of PCM’s proposed mining plan modification before conducting surface mining and reclamation 

operations to develop the Caballo West tract federal coal lease WYW172657. 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.

1.3.2 Need

The need for this action is to provide PCM the opportunity to exercise its valid existing rights 

granted by the BLM under federal coal lease WYW172657 to access and mine these federal coal 

reserves located in the tract. ASLM approval of the federal mining plan modification is necessary 

to mine the reserves.

1.4 Regulatory Framework and Necessary Authorizations

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

requirements for developing federal coal resources:

1. MLA,

2. NEPA,

3. Mining and Minerals Policy Act of 1970,

4. Federal Coal Leasing Act Amendment, 1976,

5. Federal Land Policy Management Act of 1976,

6. SMCRA,

7. Multiple-Use Sustained Yield Act of 1960,

8. ESA,

9. Clean Air Act (CAA),

10. Clean Water Act,

11. Safe Drinking Water Act,

12. NHPA,

13. American Indian Religious Freedom Act,

14. Paleontological Resources Preservation Act of 2009, and

15. Migratory Bird Treaty Act (MBTA).

In addition, this EA follows guidance in DOI 516 DM (DOI 2004), which, as outlined in 43 CFR 

Part 46, is the DOI manual guiding the implementation of the NEPA process. An MPDD will be 

prepared and submitted to the ASLM for the federal mining plan modification.

1.5 Outreach and Issues

Following a review of the 2009 SGAC EIS, OSMRE determined that further analyses were 

appropriate, based on newly available information and changes to the environmental 

consequences of the Proposed Action that have occurred since the 2009 analysis. Internal 

discussions within OSMRE identified a preliminary set of issues to be considered during the NEPA 

analysis. OSMRE also published a notice of intent (NOI) to prepare this EA in the Gillette News
Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 1-7

Chapter 1- Purpose and Need

Record on December 19, 2018 (appendix A), initiating a comment period ending on January

19, 2019. The public scoping period was initially conducted between December 19, 2018 and 

January 18, 2019; however, the OSMRE Western Region website was inaccessible from late 

December 2018 through January 2019 due to the government shutdown. Therefore, OSMRE 

extended the scoping period from February 7, 2019 through February 22, 2019. Substantive issues 

identified during public scoping were considered during the document preparation. The public 

scoping comment letters are summarized in appendix B. The further summarized issues and the 

number of comments received associated with each issue (in parentheses) include:

1. water quality (4),

2. air quality (3),

3. wildlife (1),

4. level of NEPA/ NEPA process (2),

5. reclamation (1),

6. climate change/global warming (2), and

7. transportation (1).

1.6 Crosswalk of Resource Areas

Table 1-1 identifies the location of resource discussions presented in the 2009 SGAC EIS and 

their location in this EA, where present. While all of the resources have been considered, not all 

have been brought forward for analysis in this EA. OSMRE determined that those resources and 

potential impacts not brought forward for analysis were sufficiently documented in the 2009

SGAC EIS or that new information will not affect the decision-making process. Information 

presented in the 2009 SGAC EIS that adequately described the affected environment forspecific 

resources is incorporated by reference into this EA.

1.7 Public Involvement

On December 19, 2018, OSMRE posted an announcement of the EA on their Initiatives webpage 

(OSMRE 2019a). The announcement initiated a comment period that extended from December

19, 2018 through January 19, 2019. OSMRE also published a notice of intent (NOI) to prepare this 

EA in the Gillette News Record on December 19, 2018 (appendix A) initiating a comment 

period, ending on January 19, 2019. However, the OSMRE Western Region website was 

inaccessible from late December 2018 through January 2019 due to the government shutdown. 

Therefore, OSMRE extended the scoping period from February 7, 2019 through February 22, 

2019. Public outreach and Tribal consultation letters were also sent out to stakeholders and 

tribes that could be affected by the project. OSMRE received written and e-mailed comments

from eight entities. Lists of agencies, tribes, and individualsincluded on mailing lists, and a summary

of the public scoping comment letters received are included in appendix B.
1-8 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

Chapter 1- Purpose and Need

Table 1-1. Crosswalk of Resources Analyzed in the SGAC EIS and This EA

SGAC EIS1 Caballo West EA

Resource Affected 

Environment

Environmental 

Consequences

Affected 

Environment

Environmental 

Consequences

General Setting 3.1 3.1 3.1 4.1

Topography and Physiography 3.2.1 3.2.2 3.2 4.2

Geology, Minerals, and 

Paleontology

3.3.1.1

3.3.2.1

3.3.3.1

3.3.1.2

3.3.2.2

3.3.3.2

3.3 4.3

Air Quality and Climate 

Change

3.4.2.1

3.4.3.1

3.4.4.1.1

3.4.4.2.1

3.4.2.2

3.4.3.2

3.4.4.1.2

3.4.4.2.2

3.4 4.4

Water Resources

3.5.1.1

3.5.2.1

3.5.3.1

3.5.1.2

3.5.2.2

3.5.3.2

3.5 4.5

Alluvial Valley Floors 3.6.1 3.6.2 3.6 4.6

Wetlands 3.7.1 3.7.2 3.7 4.7

Soils 3.8.1 3.8.2 3.8 4.8

Vegetation 3.9.1 3.9.2 3.9 4.9

3.10.1.1 3.10.1.2

Wildlife (including Threatened 

and Endangered and Special 

Status Species)

3.10.2.1

3.10.3.1

3.10.4.1

3.10.5.1

3.10.6.1

3.10.2.2

3.10.3.2

3.10.4.2

3.10.5.2

3.10.6.2

3.10 4.10

3.10.7.1 3.10.7.2

Land Use and Recreation 3.11.1 3.11.2 3.11 4.11

Cultural Resources

3.12.1

3.12.1.3

3.12.3

3.12.2

3.12.3 3.12 4.12

Visual Resources 3.13.1 3.13.2 3.13 4.13

Noise 3.14.1 3.14.2 3.14 4.14

Transportation 3.15.1 3.15.2 3.15 4.15

Hazardous and Solid Waste 3.16.1 3.16.2 3.16 4.16

3.17.1.1 3.17.1.2

3.17.2.1 3.17.2.2

Socioeconomics

3.17.3.1

3.17.4.1

3.17.5.1

3.17.3.2

3.17.4.2

3.17.5.2

3.17 4.17

3.17.6.1 3.17.6.2

3.17.7.1 3.17.7.2 1 SGAC EIS – South Gillette Area Coal Lease Applications EIS (BLM2009)
Chapter 2 – Proposed Action and Alternatives

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 2-1

2.0 Proposed Action and Alternatives

Under the requirements of NEPA, an EA must evaluate the environmental impacts of a reasonable 

range of alternatives that meet the project’s purpose and need. The DOI’s NEPA implementing 

regulations define reasonable alternatives as those that are “technically and economically practical 

or feasible and meet the purpose and need of the proposed action” (43 CFR § 46.420). This 

chapter describes the Proposed Action and the No Action Alternative considered and analyzed 

in detail in this EA. In addition, it identifies alternatives considered but eliminated from detailed 

analysis.

2.1 Description of Alternatives

The Proposed Action and No Action Alternative reflect the proposal for a federal mining plan 

modification to add approximately 130.2 Mt of federal coal to the federal mining plan within the 

1,024 acre Caballo West tract. This EA reflects the modified alternative selected by BLM when 

approving the lease of the federal coal associated with lease WYW172657 (BLM 2010) and 

incorporates WDEQ-LQD’s written findings to PCM’s PAP for a permit revision to include lease 

WYW172657 (WDEQ-LQD 2015a). Table 2-1 summarizes coal production, surface 

disturbance, mine life, and employees for the No Action Alternative and the Proposed Action. 

The No Action Alternative would leave operations as described in the currently approved federal 

mining plan. The Proposed Action would add additional coal associated with federal lease 

WYW172657.

Table 2-1. Comparison of Coal Production, Surface Disturbance, Mine Life, and 

Employees for the No Action Alternative and Proposed Action

Item

No Action Alternative 

(Existing Mine) Proposed Action

Mineable Federal Coal 363.9 Mt 494.1 Mt 

(130.2 Mt added)

Recoverable Federal Coal 324.11 Mt 443.92 Mt 

(119.82 Mt added)

Coal Lease Area - Federal Coal Leases Only 7,501.5 acres 8,525.5 acres

(1,024.0 acres added)

Total Affected Area 13,395.5 acres 14,262.2 acres

(866.7 acres added)

Approved Permit Area 21,268.7 acres 21,268.7 acres 

(no change)

Average Annual Coal Production 13.5 Mtpy 13.5 Mtpy 

(no change)

LOM of Federal Coal 24 years 32.9 years 

(8.9 years added)

Average Number of Employees 156 156

(no change) 1 Assumes a weighted average recovery factor of 89.1 percent of mineable coal; recovery differs by lease. 2 Assumes a 92.0 percent recovery factor of mineable coal.

2.1.1 Proposed Action

The Proposed Action would modify the federal mining plan and authorize PCM to conduct coal 

removal on approximately 1,024 acres of federal coal, with approximately 866.7 acres of surface 

disturbance, to recover approximately 119.8 Mt of federal coal. PCM estimates that at the
Chapter 2 – Proposed Action and Alternatives

2-2 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

projected average annual production rate of 13.5 million tons per year (Mtpy), mining this coal 

would extend the mine’s life by about 8.9 years. All of the federal coal included in the Proposed 

Action would be shipped to electric utilities and industrial customers in the U.S. (PCM 2018a).

The Caballo West tract consists of a single block of federal coal and includes 1,024 surface acres. 

However, not all of the coal included in the Caballo West tract is considered mineable at this 

time. Bishop Road overlies a portion of the coal included in the tract. SMCRA prohibits mining 

within 100 feet on either side of the right-of-way (ROW) of any public road unless the appropriate 

public authority allows the road to be relocated or closed after public notice, an opportunity for 

a public hearing, and a finding that the interests of the affected public and landowners would be 

protected [30 CFR § 761.11(d)]. PCM estimated that the Caballo West tract contains 

approximately 130.2 million tons (Mt) of mineable coal reserves if the Bishop Road is moved. In 

the 2009 SGAC EIS, the BLM estimated that if Bishop Road is not relocated, approximately

33.3 Mt of coal would be bypassed. The potential impacts related to this EA are evaluated 

assuming that Bishop Road is moved to recover coal under the ROW and existing buffer (100 feet 

on either side of the ROW) as well as coal that would be isolated west of Bishop Road. For this 

EA, Bishop Road is assumed to be relocated to land within the existing Caballo Mine or the 

existing Belle Ayr Mine permit boundaries, and potential impacts from the road relocation in the 

Caballo West tract are captured in the total disturbance acreage.

Under the Proposed Action, the Caballo West tract would be mined as an integral part of the 

Caballo Mine. Because the tract would be an extension of the existing Caballo Mine, the facilities 

and infrastructure would be the same as those identified in Permit No. 433, as revised on 

November 2015, and the BLM R2P2, which was approved April 2018.

2.1.2 No Action Alternative

Under the No Action Alternative, OSMRE would not recommend and the ASLM would not 

approve PCM’s proposed mining plan modification request, and 119.8 Mt of federal coal related 

to WYW172657 would not be recovered. Under this alternative, PCM would mine its remaining

324.1 Mt of recoverable coal reserves on the existing Caballo Mine federal leases in approximately 

24 years, at an average annual production rate of approximately 13.5 Mtpy.

The No Action Alternative discloses the potential consequences of not mining the Caballo West 

tract, under the assumption that the additional coal within the tract would not be mined in the 

foreseeable future if the No Action Alternative is selected. Under the No Action Alternative, 

PCM would be limited to recovering the remaining federal coal reserves associated with existing 

federal, state, and private leases. All of the federal coal included in the No Action Alternative 

would continue to be shipped to electric utilities and industrial customers in the U.S. Selection 

of the No Action Alternative would not preclude approval of a federal mining plan modification 

in the future to include mining the coal within the Caballo West tract.

2.1.3 Alternatives Considered but Eliminated from Detailed Analysis

OSMRE considered alternative scenarios to the approval, denial, or approval with conditions of 

the federal mining plan modification. However, because OSMRE's decision would be limited to 

recommending approval, approval with conditions, or denial of the mining plan modification, 

OSMRE concluded that there are no other reasonable action alternatives to the Proposed Action 

that would meet the agency’s purpose and need. The following alternatives were considered but 

eliminated from detailed analysis. The discussions include reasons the alternatives were 

eliminated from detailed analysis.
Chapter 2 – Proposed Action and Alternatives

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 2-3

2.1.3.1 Underground Mining Alternative

Public comments on other EAs in the Powder River Basin suggested an alternative to use 

underground mining methods to extract the coal. OSMRE eliminated this alternative from 

detailed study because WDEQ-LQD has approved a surface mining permit for this project using 

surface mining techniques, and underground mining is inconsistent with the approved permit. The 

purpose and need for this EA is predicated upon review of a surface mining plan included as part 

of the WDEQ-LQD-approved surface mining permit. An underground mining alternative would, 

thus, be inconsistent with the Purpose and Need for this action.

Also, lease WYW172657 is a surface reserve lease only. The lease was sold by the federal 

government and purchased and held by PCM with the clear understanding by all parties concerned 

that the lease would be mined by surface mining methods only (BLM 2011).

This alternative is also economically infeasible at current permitted production rates. Initiating an 

underground longwall mining operation in the Caballo Mine is not cost effective. The facilities and 

equipment needed for underground mining are different from surface mining. Because the 

infrastructure for underground mining is not in place at the Caballo Mine, new infrastructurefor 

underground mining would need to be constructed. The capital expenditure to develop an 

underground mine would be prohibitive. In addition, new surface facilities would need to be 

constructed, including, but not limited to, conveyors, coal stock piles, a wash plant, and 

maintenance and support facilities. In addition, all new underground mining equipment would 

need to be purchased such as, a longwall mining system, conveyor systems/drives/power stations, 

vehicles for transporting employees and supplies, continuous miners, shuttle cars, large and small 

ventilation fans, and roof bolters.

In addition, approval by WDEQ-LQD of an application for a permit revision would be required 

to authorize underground mining. It would take years for PCM to design and engineer a new 

underground mine and for WDEQ-LQD to process a new permit application. These factors also 

support the conclusion that this potential alternative is economically unreasonable.

This alternative was not brought forward for detailed analysis because underground mining does 

not respond to the purpose and need for this action, and the economic burden to shift to 

underground mining would be prohibitive.

2.1.3.2 Low or No Pollutant Emitting Equipment

Public comments on other PRB EAs suggested considering an alternative that required reduced 

air emissions by changing or modifying mining related equipment to that which would produce 

lower air emissions. The Caballo Mine 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 approximately 130 Mt of federal coal would be prohibitive and 

would only minimally 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 emission control devices would be expensive and 

would have limited effect on regional air emissions.
Chapter 2 – Proposed Action and Alternatives

2-4 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

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 Caballo Mine and would likely have substantially similar 

effects to an alternative that is analyzed.

2.1.3.3 Air Quality Mitigation Alternatives

Some public comments on other PRB EAs suggested that OSMRE consider alternatives that 

mitigate air quality impacts, specifically by imposing more stringent emission limits at power plants 

fueled by coal from the Caballo Mine and by requiring oil and gas operators in the region to 

reduce their emissions. These proposals are not alternatives to the mining plan being considered. 

The effects of coal combustion are analyzed in the Proposed Action and No Action Alternative 

because they are considered to be indirect effects. CEQ regulations at 40 CFR § 1508.8(b) define 

indirect effects as those “which are caused by the 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 concludes there would not be significant impacts to 

air resources under the Proposed Action, and no mitigation is recommended. 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. Given these factors, bringing this alternative forward for further review 

would not be reasonable.

2.2 Existing Conditions (Conditions Common to the Proposed Action 

and the No Action Alternative)

The 2009 SGAC EIS presented a thorough description of the existing conditions to support the 

analysis presented therein. The following summary of updated existing conditions, including 

ongoing permitted mining operations, describes notable changes since the 2009 SGAC EIS was 

prepared. This update is provided to support the evaluation of potential impacts contained in 

chapter 4 of this EA.

Mining and reclamation activities have continued at the Caballo Mine as approved by WDEQLQD Permit No. 433 since the 2009 SGAC EIS was prepared and federal coal lease WYW172657 

was issued. The PAP, including approved revisions, provides the most complete descriptions of 

mining, environmental protection measures, and reclamation activities within the project area for 

the LOM and, as such, is used and referenced for the purpose of this EA.

PCM currently employs 156 people at the Caballo Mine (PCM 2018a). From 2011-2017, the mine 

produced an average of 13.1 Mt of coal per year (Wyoming Department of Workforce Services 

[WDWS] 2011, 2012, 2013, 2014, 2015, 2016, 2017). In the future, PCM anticipates mining

13.5 Mt annually, which is under the 35 Mt of coal per year permitted by WDEQ Air Quality 

Division (AQD) air quality permit MD-1477. Approximately 324.1 Mt remain to be recovered in 

the federal mining plan area after January 1, 2018, excluding the federal coal identified in Proposed 

Action. PCM continues to use conventional surface mining techniques described in section 2.3.1 

of the 2009 SGAC EIS. PCM estimates that the Caballo Mine currently recovers approximately 

89 percent of mineable coal. Coal is shipped from an onsite railroad loading facility to electric 

utilities and industrial customers in the U.S. (PCM 2019).

In 1975, in response to the requirements set forth in SMCRA and in the WEQA, WDEQ-LQD 

published a set of rules and regulations that require coal mine permittees to restore the land to 

a condition equal to or greater than its highest previous use and required permittees to restore
Chapter 2 – Proposed Action and Alternatives

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 2-5

wildlife habitat commensurate with or superior to premining habitat (WDEQ-LQD 2012). 

Reclamation activities under the Proposed Action would be consistent with those currently used 

at the Caballo Mine. Mined-out areas would be reclaimed according to an approved postmining

plan and would be reclaimed to reestablish the drainage system. In-channel stockponds and playas 

(shallow topographic depressions that are internally drained) would be replaced to provide 

livestock and wildlife watering sources. All postmining topography, including reconstructed 

drainages, must be approved by the WDEQ-LQD. After mining, the land would be reclaimed to 

support the approved postmining land uses.

2.2.1 Current Bonding and Bond Release Status

SMCRA provides that, as a prerequisite for obtaining or modifying a coal mining permit, 

permittees must post a reclamation bond to ensure that the regulatory authority would have 

sufficient funds to reclaim the site if the permittee fails to complete obligations set forth in the 

approved reclamation plan (OSMRE 2019b). The current bond amount for the Caballo Mine is

$151.9 million in the form of a surety bond. It was approved by WDEQ-LQD on November 13, 

2018.

There are four types of bond release for areas disturbed and coal removed after May 1978 for 

which mine operators may apply to reduce their reclamation bond. As outlined in WDEQ-LQD 

Guideline 20 (Bond Release Categories and Submittal Procedures for Coal Mines [WDEQ-LQD 

2014a]), these include:

1. Area Bond Release - Rough backfill verification;

2. Phase 1 - Partial Incremental, which includes stream channel reconstruction verification 

and soil depth verification;

3. Phase 2 - Partial Incremental, which includes vegetation establishment verification, 

surficial stability verification, and permanent impoundment construction/renovation 

and SEO approval verification; and

4. Phase 3 - Full Incremental or Final release, which includes mitigation wetlands 

verification, revegetation success verification, and tree establishment verification.

All reclaimed areas are monitored for a minimum of 10 years to evaluate the success of vegetation 

growth and the establishment of a variety of plant species prior to the Phase 3 final release of the 

reclamation bond. It is important not to equate contemporaneous reclamation with final bond 

release. There is a difference between lands that are in various stages of reclamation and those 

that have been reclaimed and released from final bonding requirements. Final bond release on 

reclaimed lands indicates that the reclamation meeting permit standards has been in place in 

accordance with permit standards for at least 10 years and that an application for final bond 

release has been submitted to the WDEQ. In 2017, the OSMRE Denver Field Division evaluated 

reclamation plans of four approved permits in Wyoming during oversight inspections and 

determined that all permits evaluated were in compliance with contemporaneous reclamation 

requirements, as defined within the approved permits (OSMRE 2017). According to Caballo 

Mine’s 2018 Annual Report (PCM 2018b), the mine had disturbed approximately 8,619 acres, of 

which approximately 1,470 acres (17.1 percent) are needed for long-term mining activities and, 

as such, are considered land not available for reclamation. The areas listed as needed for longterm mining activities include main facilities (buildings, coal handling facilities, and ancillary 

facilities) and mining operations (train loadout, railroad loop, explosives storage area, scoria pits, 

landfarm, sediment control ponds and diversions, the access road, and miscellaneous haul roads 

and light use roads). As of March 2018, the mine had backfilled and graded approximately
Chapter 2 – Proposed Action and Alternatives

2-6 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

5,111 acres of the remaining 7,149 acres. Thus, the mine had backfilled and graded approximately

59.3 percent of the total disturbance and approximately 71.5 percent of land available for 

reclamation. A summary of phased bond release acreages in the project area is included in table

2-2.

Table 2-2. Summary of Phased Bond Release Acreages in the Project Area

Phased Bond Releases Status1 Mine Wide Percent

Total Areas Disturbed 8,619 --

Acres of Long-term Mining or Facilities and Percent of Total Disturbance 1,470 17.1

Acres Available for Backfilling or Reclamation and Percent of Total Disturbance 7,149 82.9

Acres of Active Mining and Percent of Available Acres 2,038 28.5

Acres Backfilled and Graded and Percent of Available Acres 5,111 71.5

Total Areas Reclaimed (Soiled and Seeded/Planted) and Percent of Backfilled and Graded 4,212 82.4

Areas Which Have Achieved Phase 1 Bond Release and Percent of Reclaimed Acres 4,060 96.4

Areas Which Have Achieved Phase 2 Bond Release and Percent of Reclaimed Acres 3,921 93.1

Areas Which Have Achieved Phase 3 Bond Release and Percent of Reclaimed Acres 0 0 1 As of March 31, 2018 

Source: PCM 2018b

It should be noted that neither state nor federal regulations require a permittee to file for bond 

release at any prescribed time. Therefore, only using bond release statistics to evaluate 

reclamation success can be misleading. Typically, permittees do not file for Phase 2 or Phase 3 

bond release until completion of the entire mining operation. As a result, the number of acres 

released from Phase 1 and Phase 3 bond in Wyoming is relatively small compared to the number 

of acres actually regraded, topsoiled, and seeded. The standard for determining if mines are 

meeting their reclamation obligations is related to compliance with contemporaneous 

reclamation permit commitments. Contemporaneous reclamation specifically refers to the 

timeliness in which reclamation is occurring. An evaluation is conducted annually by OSMRE. 

According to the 2017 Annual Evaluation Report for the WDEQ Regulatory Program, all coal 

mines evaluated were found to be in compliance that evaluation year (OSMRE 2017).
Chapter 3 – Affected Environment

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 3-1

3.0 Affected Environment

This chapter discusses the existing conditions of the physical, biological, cultural, and human 

resources that could be affected by implementation of the alternatives described in chapter 2. 

Table 1-1 in chapter 1 is a crosswalk table between resource discussions presented in the 2009 

SGAC EIS and this EA. The determination of adequacy of the description of baseline conditions 

in the 2009 SGAC EIS, as related to the Caballo West tract was made if conditions have not 

substantively changed, no new data are available, or the resource conditions have only been 

minimally affected as a result of current mining operations and further presentation of information 

would not affect the decision-making process. Baseline information in the 2009 SGAC EIS that 

has not substantively changed is incorporated by reference. Updated baseline information is 

presented in this chapter, when applicable.

3.1 General Setting

The general setting of the Caballo West tract is described in section 3.1 of the 2009 SGAC EIS. 

The tract is located in the PRB, which has a semi-arid, high plains environment with relatively 

large seasonal and diurnal variations in temperature and seasonal variation in precipitation.

3.2 Topography and Physiography

Topography and physiography of the Caballo West tract are described in section 3.2.1 and section 

S3-1 of the Supplementary Information volume of the 2009 SGAC EIS. The tract lies within the 

unglaciated Missouri Plateau subregion of the Great Plains Province, within the east-central 

portion of the PRB. The structural basin is an elongated, asymmetrical syncline approximately 120

miles east to west and 200 miles north to south, which is bounded in Wyoming by the Black Hills 

on the east; the Big Horn Mountains on the west; and the Hartville Uplift, Casper Arch, and

Laramie Mountains on the south. Geologic strata along the eastern limb of the structural PRB dip 

to the west at 1 to 2 degrees toward the axis of the basin.

3.3 Geology, Mineral Resources, and Paleontology

General geology and coal resources are described in section 3.3.1.1 and section S3-2 of the 

Supplementary Information volume of the 2009 SGAC EIS. Stratigraphic units within the Caballo 

West tract include, in descending order, recent (Holocene age) alluvial and eolian deposits, 

Eocene age Wasatch Formation (overburden), and Paleocene age Fort Union Formation. The 

targeted coal seam lies within the Tongue River Member of the Fort Union Formation. Locally, 

this coal zone is referred to as the Wyodak. Within the tract, the Wyodak coal seam thickness 

averages about 74 feet.

Mineral resources are described in Section 3.3.2.1 of the 2009 SGAC EIS. According to the 

Wyoming Oil and Gas Conservation Commission (WOGCC), as of July 2018, 66 CBNG wells 

and 1 oil and gas well had been permitted within 2 miles of the tract (WOGCC 2018). Nine 

CBNG wells have been completed within the tract, six of which are currently producing gas. As 

of July 2018, there are no oil and gas wells other than CBNG permitted within the tract. CBNG 

wells located on the Caballo West tract would be abandoned and mined through as mining 

progresses.

Paleontology is described in section 3.3.3.1 and section S3-3 of the Supplementary Information 

volume of the 2009 SGAC EIS. No significant or unique paleontological resource localities were 

recorded on federal lands in the 2009 SGAC EIS resource report area. In 2008, a reconnaissance
Chapter 3 – Affected Environment

3-2 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

for outcrops that might contain paleontological remains was conducted within and adjacent to 

the Caballo West tract. No outcrops or paleontological remains were identified (PCM 2014).

3.4 Air Quality and Climate Change

Air quality regulations applicable to surface coal mining include the National Ambient Air Quality 

Standards (NAAQS), Wyoming Ambient Air Quality Standards (WAAQS), Prevention of 

Significant Deterioration (PSD), National Source Performance Standards (NSPS), and the Federal 

Operating Permit Program (Title V). These regulatory programs are described in detail in 

appendix H of the 2009 SGAC EIS.

Air quality information specific to the Caballo Mine is included in PCM’s Air Permit MD-1477 

(WDEQ- AQD 2006). Since the completion of the 2009 SGAC EIS, a permit waiver was issued 

for the air permit to reduce the maximum permitted annual production level from 50 to 35 Mt 

(WDEQ-AQD 2014).

Section 3.4 and appendix K of the 2009 SGAC EIS include detailed air quality discussions regarding 

the leasing and mining of coal related to the Caballo West tract. The analysis presented herein 

includes discussion of attainment/non-attainment areas; updated to recent air quality monitoring 

findings; revised air quality modeling results; updated discussions on fine particulate matter 

(PM2.5), nitrogen dioxide (NO2), ozone (O3), air quality related values (AQRVs), and hazardous 

air pollutants (HAPs); and discussion of greenhouse gases(GHGs).

3.4.1 Existing Caballo Mine Air Quality Summary

Baseline air quality data for the surface facilities area at the Caballo Mine are found in the section 

3.4 and section S3-4 of the Supplementary Information volume of the 2009 SGAC. The climate 

in the general area is semi-arid with relatively short, warm summers and longer cold winters. 

Evaporation exceeds annual precipitation. The following discussions include updated (2013-2017) 

air quality monitoring results.

3.4.1.1 Air Quality-Monitoring Values

PCM has monitored particulate matter levels around the mine throughout its life. Current air 

monitoring consists of two sites that monitor continuous concentrations of PM10 (map 3-1). 

Table 3-1 lists the recent annual mean and high PM10 concentrations for the Caballo Mine. Site 

BA-1 is a Belle Ayr Mine sampler, located within the Caballo Mine permit boundary. The average 

annual PM10 concentration from 2013-2018 ranged between 8.1 and 18.2 μg/m3 (about 16 to 36 

percent of the annual WAAQS of 50 μg/m3

). The 24-hour high PM10 values ranged between

27.0 and 131.7 μg/m3

, or about 18 to 88 percent of the WAAQS and NAAQS of 150 μg/m3.

Table 3-1. Average Annual and Maximum 24-hr PM10 Concentrations (μg/m3

) for 

the Caballo Mine

Site 

Name1

2013 2014 2015 2016 2017 2018

Avg 

Annual

Max 

24-hr

Avg 

Annual

Max 

24-hr

Avg 

Annual

Max 

24-hr

Avg 

Annual

Max 

24-hr

Avg 

Annual

Max 

24-hr

Avg 

Annual

Max 

24-hr

CB8 17.7 84.1 16.7 55.6 18.2 80.8 16.2 121.0 16.9 131.7 14.3 55.3

CB9 16.1 64.2 14.9 54.0 17.4 72.1 15.6 102.8 16.2 117.0 13.5 53.0

BA-1 8.1 27.0 9.7 28.0 10.7 49.0 9.3 44.0 9.0 71.0 8.8 28.2 1 See map 3-1 for site locations.

Source: IML 2013, 2014, 2015, 2016, 2017, 2018
Chapter 3 – Affected Environment

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 3-3

Map 3-1. Wind Rose and Air Quality and Meteorological Monitoring Stations at 

the Caballo Mine and Surrounding Mines
Chapter 3 – Affected Environment

3-4 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

Because PM2.5 monitoring is not required by WDEQ-AQD, data were not gathered onsite. 

Therefore, PM2.5 data gathered from three Campbell County sites from 2013-2018 were used to 

assess potential PM2.5 emissions at the Caballo Mine (table 3-2). Regional monitoring 

demonstrated that ambient concentrations of PM2.5, as determined by the 98th percentile 24-hour 

standard and annual average NAAQS and WAAQS values, were below the established 24-hour 

(35 μg/m3

) and annual (12 μg/m3) standards.

Table 3-2. Measured PM2.5 Concentrations in Campbell County

Site ID1 Year 24-hour (μg/m3) Annual (μg/m3)

Btm-36-2

2013

2014

14

10

4.2*

3.9

(Black Thunder Mine) 2015 22 4.9*

(56-005-0891) 2016

2017

12

26

3.3*

5.5*

2018 21 4.8*

Belle Ayr Ba-4, 5n, 5s

2013

2014

14

10

6.4*

5.2

(56-005-0892) 2015

2016

18

14

5.0

4.6*

2017 23 5.4

2018 20 3.5*

Buckskin Mine North Site

2013

2014

14

12

4.8

5.5

(56-005-1899) 2015

2016

21

10

2.2

2.5*

2017 26 5.6

2018 23 5.3* 1 See map 3-2 for locations.

* Indicates the mean does not satisfy minimum data completeness criteria. 

Source: EPA 2019a

To further evaluate potential PM2.5 emissions at the Caballo Mine, PM10 monitoring data fromthe 

Caballo Mine were used to estimate PM2.5 ambient concentrations by applying a 0.2 factor, as 

determined by Pace (2005). The estimated annual average and maximum 24-hour PM2.5 values are 

shown in table 3-3. The estimated PM2.5 concentrations were below the prescribed 24-hour 

WAAQS and NAAQS (35 μg/m3

) and the annual WAAQS and NAAQS (15 μg/m3 and 12 μg/m3, 

respectively). These estimates are supported by the regional PM2.5 data presented in table3-2.

Table 3-3. Estimated Average Annual and Maximum 24-hr PM2.5 Concentrations 

(μg/m3

) for the Caballo Mine

Site 

Name1

2013 2014 2015 2016 2017 2018

Avg 

Annual

Max 

24-hr

Avg 

Annual

Max 

24-hr

Avg 

Annual

Max 

24-hr

Avg 

Annual

Max 

24-hr

Avg 

Annual

Max 

24-hr

Avg 

Annual

Max 

24-hr

CB8 3.5 16.8 3.3 11.1 3.6 16.2 3.2 24.2 3.4 26.3 2.9 11.0

CB9 3.2 12.8 3.0 10.8 3.5 14.4 3.1 20.1 3.2 23.4 2.7 10.6 1 See map 3-1 for site locations.

Source: Calculated (PM10 values from table 3-2 multiplied by 0.2)

3.4.1.2 Emissions of Nitrogen Dioxide (NO2), Ozone (O3), Sulfur Dioxide (SO2), 

Mercury (Hg), and Lead (Pb)

NO2 concentrations (98th percentile, 1-hour) have been monitored in Campbell County at four 

Air Quality System (AQS) monitoring sites (table 3-4). These monitoring sites are the closest 

to the Caballo Mine, between 3 and 36 miles from the Caballo West tract (map 3-2). All 

monitored NO2 values were well below the WAAQS of 100 ppb.
Chapter 3 – Affected Environment

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 3-5

Map 3-2. Regional Air Quality Monitoring Sites
Chapter 3 – Affected Environment

3-6 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

Table 3-4. Measured NO2 Concentrations (ppb) in Campbell County

AQS Site 

ID1

Sampler ID 2013 2014 2015 2016 2017 2018

56-005-0123 Thunder Basin Grassland Site 9 10 8 6 8 7

56-005-0456 South Campbell County 32 32 32 28 31 32

56-005-0892 Belle Ayr Ba-4, Ba-5n, and Ba-5s 35 35 32 26 28 30

56-005-0011 Hilight-Reno Junction Gas Plant 52 55 41 No 

data

No 

data

No 

data 1 See map 3-2 for site locations. 

Source: EPA 2019a

Under the CAA, EPA has set protective health-based standards for O3. O3 monitoring is not 

required by WDEQ-AQD at the mines evaluated in the 2009 SGAC EIS, but levels have been 

monitored at two WDEQ-AQD monitoring sites in Campbell County since 2001. An exceedance 

of the current O3 8-hour standard occurs if the 4th-highest daily maximum value is above the level 

of the current NAAQS and WAAQS standard (0.075 ppm prior to October 2015, 0.070 ppm 

after October 2015). Table 3-5 shows no violations of the NAAQS or WAAQS 8-hour O3 

standards at the two regional monitoring sites, during 2013-2017.

Table 3-5. Measured O3 Concentrations (ppm) in Campbell County

AQS Site 

ID1 Sampler ID 2013 2014 2015 2016 2017 2018

56-005-0123 Thunder Basin Grassland Site 0.061 0.058 0.059 0.057 0.064 0.064

56-005-0456 South Campbell County 0.061 0.059 0.062 0.060 0.068 0.055 1 See map 3-2 for site locations. 

Source: EPA 2019a

SO2 concentrations (99th percentile, 1-hour) are currently being monitored in Campbell County 

at one AQS monitoring site (table 3-6). This site is approximately 9 miles north of the Caballo 

West tract (map 3-2). All monitored SO2 values were well below the NAAQS and WAAQS of 

75 ppb.

Table 3-6. Measured SO2 Concentrations (μg/m3) in Campbell County

AQS Site ID1 Sampler ID 2013 2014 2015 2016 2017 2018

56-005-0857 Wyodak Site 4 37 32 16 14 11 No 

data 1 See map 3-2 for site locations. 

Source: EPA 2019a

Annual Pb (a criteria pollutant), Hg (a HAP), and CO (an indirect GHG) monitoring values are 

not collected at the Caballo Mine. Table 3-7 shows the Pb emissions from three coal-fired power 

plants and one AQS monitoring site in Campbell County. The Pb values from the Thunder Basin 

site were well below the NAAQS and WAAQS of 0.15 μg/m3

.

Table 3-7. Measured Annual Pb Air Emissions from Three Campbell County 

Power Stations and One Campbell County Coal Mine

Power Station or AQS Site 2013 2014 2015 2016 2017

Wyodak Plant (pounds) 43.1 35.3 33.2 19.7 27.3

Dry Fork Station (pounds) 9.0 21.0 8.6 14.0 10.0

Neil Simpson Complex (pounds) 60.0 31.0 24.0 24.0 23.0

Thunder Basin (56-005-0123) (μg/m3)

1 0.002 0.001 0.002 0.002 0.001 1 Pb monitoring at the Thunder Basin AQS site is presented as annual 1st maximum value. 

Source: EPA 2019b
Chapter 3 – Affected Environment

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 3-7

Table 3-8 shows the Hg emissions from three coal-fired power plants in Campbell County.

Table 3-8. Measured Annual Hg Stack (Air) Emissions from Power Stations in 

Campbell County (Pounds)

Power Station1 2013 2014 2015 2016 2017

Wyodak Plant

Total Emissions 338.3 347.2 319.0 261.7 464.3

Stack (Air) Emissions 204.3 301.1 111.2 22.6 28.3

Percent of Total Emission Emitted to Air 60% 87% 35% 9% 6%

Dry Fork Station

Total Emissions 86.0 69.0 66.7 45.0 48.0

Stack (Air) Emissions 67.0 50.0 38.3 28.0 29.0

Percent of Total Emission Emitted to Air 78% 72% 57% 62% 60%

Neil Simpson Complex

Total Emissions 13,086.02 653.0 711.0 759.0 1,017.0

Stack (Air) Emissions 378.0 354.0 351.0 358.0 433.0

Percent of Total Emission Emitted to Air 3%1 54% 49% 47% 43%

Total of Three Campbell County Power Stations

Total Emissions 13,510.32 1,069.2 1,096.7 1,065.7 1,529.3

Stack (Air) Emissions 649.3 705.1 500.5 408.6 490.3

Percent of Total Emission Emitted to Air 5%2 66% 46% 38% 32% 1 See map 3-2 for site locations. 2 2013 Neil Simpson total emissions value on the EPA website appears to be incorrect given the significantly lower values compared to other 

years, so the percent of stack emissions compared to total emissions for 2013 calculations appears to be invalid.

Source: EPA 2019b

CO is created when carbon-containing fuels are burned incompletely. Through natural processes 

in the atmosphere, it is eventually oxidized to CO2. CO is not monitored in Campbell County.

3.4.1.3 Air Quality Related Values (AQRVs)

AQRVs, as related to the Caballo West tract, were discussed in section 3.4.4 of the 2009 SGAC 

EIS. Updated information regarding AQRVs is included below. AQRVs are evaluated by the land 

management agency responsible for a PSD Class I area, according to the agency’s level of 

acceptable change (LAC). These AQRVs include potential air pollutant effects on visibility and the 

acidification of lakes and streams. The AQRVs, and the associated LAC, are applied to PSD Class I 

and Class II areas. They are the land management agency’s policy and are not legally enforceable 

as a standard. WDEQ-AQD WAAQS do include a standard for visibility. Class I areas are afforded 

specific AQRV protection under the CAA. The Class I designation allows very little deterioration 

of air quality. The nearest Class I area is approximately 100 miles east-southeast of the tract at 

Wind Cave National Park in South Dakota (map 3-2). The AQRVs associated with this action 

include visibility and acidification of lakes.

3.4.1.3.1 Visibility

Surface coal mines are not considered to be major emitting facilities in accordance with the 

WDEQ Rules and Regulations (chapter 6, section 4). Therefore, the State of Wyoming does not 

require mines to evaluate their impacts on Class I areas, though the BLM does consider such 

issues during leasing. The current visibility discussions have been inferred from the currently 

permitted mining activities related to the existing coal leases at the Caballo Mine. Visibility can be

defined as the distance one can see and the ability to perceive color, contrast, and detail. PM2.5 is 

the main cause of visibility impairment. Visibility impairment is expressed in terms of
Chapter 3 – Affected Environment

3-8 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

deciview (dv). The dv index was developed as a linear perceived visual change (Pitchford and 

Malm 1994) and is the unit of measure used in the EPA’s Regional Haze Rule to achieve the 

National Visibility Goal. A change in visibility of 1.0 dv represents a “just noticeable change” by 

an average person under most circumstances. Increasing dv values represent proportionately 

larger perceived visibility impairment. Figure 3-1 shows the clearest days, the haziest days, and 

the natural conditions (i.e., the visibility conditions as they were before human activities) for the 

Wind Cave monitoring site for 2000-2017 (IMPROVE 2019). The long-term trend in visibility at 

Wind Cave National Park appears to be relatively stable, if not improving slightly.

Figure 3-1. Visibility in the Wind Cave National Park

3.4.1.3.2 AQRVs Related to Coal Combustion

Emissions that affect air quality also result from combustion of fossil fuels. Table 3-9 presents 

the estimated PM10, PM2.5, SO2, NOX, and Hg emissions estimates for coal mined at the Caballo

Mine that was utilized for power generation.

Table 3-9. Estimated Annual PM10, PM2.5, SO2, NOX, and Hg Contributions (tons) 

from Caballo Mine Coal Combustion

Source 2013 2014 2015 2016 2017

Mt Coal Recovered 9.0 8.0 11.4 11.2 11.1

PM10 6,239.0 5,552.4 7,922.6 7,797.1 7,730.7

PM2.5 1,902.9 1,693.5 2,416.4 2,378.1 2,357.9

SO2 Emissions 78,567.2 69,921.1 99,768.9 98,188.6 97,352.1

NOX Emissions 32,324.8 28,767.5 41,047.8 40,397.6 40,053.4

Hg Emissions 0.4 0.3 0.6 0.5 0.5

Source: WWC 2019, calculations are provided in appendix C

3.4.1.3.3 Acidification of Lakes/Acid Deposition

Acid deposition causes acidification of lakes and streams, which can have direct impacts on aquatic 

habitats and contribute to the damage of trees at high elevation and many sensitive forest soils. 

Acid rain is measured as acidity and alkalinity using a pH which for which 7.0 is neutral. The lower 

a substances pH, the more acidic it is. Normal rain has a pH of about 5.6 (EPA 2019c). The 

National Atmospheric Deposition Program (NADP) monitors precipitation chemistry at various 

sites around the U.S. The nearest site to the Caballo Mine is Site WY99 in Newcastle
Chapter 3 – Affected Environment

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 3-9

(map 3-2), which measures free acidity (H+ as pH). Table 3-10 provides the measured pH for 

2013-2017. The trend in pH at monitoring site WY99 appears to be relatively stable.

Table 3-10. Measured Hydrogen Ion (H+) Concentrations at Monitoring Site WY99

Parameter 2013 2014 2015 2016 2017

pH 5.9 5.8 5.9 5.9 5.8

Source: NADP 2014-2018

3.4.1.4 Greenhouse Gases (GHGs) and Climate Change

GHGs include CO2, methane (CH4), nitrous oxide (N2O), and fluorinated gases 

(hydrofluorocarbons, perfluorocarbons, nitrogen trifluoride, and sulfur hexafluoride) (EPA 

2019d). For consistency between projects, OSMRE describes GHG emissions in terms of “CO2-

equivalents” (CO2e). For climate, climate change, and GHG analysis, there is no specific analysis 

area and project emissions are used as a proxy.

CO2 is emitted from the combustion of fossil fuels, including coal. CH4 canbe emitted during the 

production and transport of coal. N2O is emitted during agricultural and industrial activities, as 

well as during combustion of fossil fuels and solid waste. Fluorinated gases are synthetic, powerful 

GHGs that are emitted from a variety of industrial processes. CO2 and other GHGs are naturally 

occurring gases in the atmosphere; their status as a pollutant is not related to their toxicity, but 

instead is due to the added long-term impacts they may have on climate because of their increased 

incremental levels in the earth’s atmosphere. Because they are non-toxic and non-hazardous at 

normal ambient concentrations, CO2 and other naturally occurring GHGs do not have applicable 

ambient standards or emission limits under the major environmental regulatory programs. Each 

GHG has a different lifetime in the atmosphere and a different ability to trap heat in the 

atmosphere. To allow different gases to be compared and added together, emissions can be 

converted into CO2e emissions. This measure is used to compare the capacity of each GHG to 

trap heat (Global Warming Potential, or GWP) in the atmosphere relative to that of CO2, which 

is used as a reference gas. The CO2e for a gas is derived by multiplying the amount of gas emitted 

by its 100-year GWP conversion factor (CEC 2011).

Estimates related to mining include emissions from all sources, including all types of carbon fuels 

used in the mining operations, electricity used on site (i.e., lighting for facilities, roads, and 

operations and electrically powered equipment and conveyors), the mining processes (i.e., 

blasting, coal fires caused by spontaneous combustion, methane released [vented] from exposed 

coal seams), and coal combustion. Direct CO2e emissions include emissions directly related to 

the recovery of coal. Indirect emission result from the transportation of the coal to and

combustion of the coal at power plants. Although the Caballo Mine has not completed CO2e 

emissions inventories resulting from current coal recovery, these emissions were estimated by 

applying CO2e emission ratios (CO2e per Mt of coal produced, per Mt cubic yards of overburden 

moved, and CO2e per acre of disturbance) from adjacent mines to recent Caballo Mine 

production (tonnages). This assumes that because mining methods and circumstances are similar, 

the estimated CO2e emission ratios for the Caballo Mine would be similar to the calculated ratios 

at adjacent mines. Annual direct CO2e emissions estimates for the Caballo Mine from 2013-2017 

are shown in table 3-11. The estimated annual amount of direct CO2e emissions ranged between 

56,614 and 80,781 metric tons per year, averaging approximately 71,867 metric tons per year 

from mining an annual average of 10.1 Mt of coal.

The amount of CO2e emitted from combustion of the coal was calculated using an emission factor 

that considered the carbon content and heating value of the fuel used (EPA 2019e). Table 3-11
Chapter 3 – Affected Environment

3-10 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

shows that the estimated annual amount of Caballo Mine indirect CO2e emissions, including 

transportation and combustion, ranged between 13,691,252 and 19,500,302 metric tons, 

averaging 17,393,594 metric tons per year from 2013-2017.

Table 3-11. Estimated Caballo Mine Direct and Indirect CO2e Emissions at the 

Caballo Mine from Coal Combustion

2013 2014 2015 2016 2017 Average

General

Mt of Coal Recovered 8.98 7.99 11.40 11.22 11.10 10.14

Average Transport Miles 

(One Way) 1,052 1,098 1,009 1,238 1,260 1,131

Number of Train Trips 

(One Way) 580 516 737 725 718 655

Direct Emissions Sources1

Fuel1 29,334 26,106 37,250 36,660 36,347 33,139

Electricity Consumed in Mining 

Process1 23,975 21,337 30,445 29,963 29,707 27,085

Mining Process1 10,305 9,171 13,086 12,879 12,769 11,642

Total Direct Emissions1 63,614 56,614 80,781 79,501 78,824 71,867

Indirect Emissions Sources

Rail Transport2 329,811 306,350 401,692 485,053 489,467 402,475

From Coal Combustion1 15,040,011 13,384,902 19,098,610 18,796,108 18,635,965 16,991,119

Total Indirect Emissions1 15,369,822 13,691,252 19,500,302 19,281,161 19,125,431 17,393,594

Total Estimated CO2e 

Emissions1 15,433,436 13,747,866 19,581,083 19,360,663 19,204,255 17,465,460

1 In metric tons 2 Coal haulage emissions based on 130-car trains with four locomotives; 488.2 kg CO2e per mile per loaded train, 96.1 kg CO2e per mile 

per empty train; and one-way mileage to power plants. Coal haulage emissions calculations includes a loaded train and a returning empty 

train, per train trip.

Source: WWC 2019, calculations are provided in appendix C

Total CO2e emissions from coal mined at the Caballo Mine from 2013-2017 ranged between 

13,747,866 and 19,581,083 metric tons, averaging 17,465,460 metric tons per year. Combustion 

of coal from the Caballo Mine used for electricity generation accounted for approximately

99.6 percent of the total CO2e emissions from coal mined.

3.5 Water Resources

Sections 3.5.1.1, 3.5.2.1, and 3.5.3.1 and section S3-5 of the Supplementary Information volume 

of the 2009 SGAC EIS include detailed discussions of water resources related to the leasing and 

mining of coal within the Caballo West tract. The analyses included herein serve to update 

discussions with recent groundwater and surface water quality monitoring results and update 

water rights discussions.

3.5.1 Groundwater

Section 3.5.1.1 and section S3-5.1 of the Supplementary Information volume of the 2009 SGAC 

EIS provide a detailed discussion of the groundwater resources of the Caballo West tract. The 

analysis area contains three water-bearing geologic units that have been directly affected by 

existing mining activities and would be directly affected by mining the Caballo West tract. In 

descending order, these units are the recent alluvium, the Wasatch Formation overburden, and 

the mineable coal seam in the Tongue River Member of the Fort Union Formation, referred to 

as the Wyodak coal seam. A chart showing the stratigraphic relationships of the surface and 

subsurface geologic units in the analysis area is provided as figure 3-2 in the 2009 SGAC EIS.
Chapter 3 – Affected Environment

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 3-11

As indicated in the 2009 SGAC EIS, the underlying, sub-coal Fort Union Formation and the Fox 

Hills Sandstone are used for water supply at local coal mines within the general Caballo West 

tract analysis area, at depth between 850 and 4,000 feet. At these depths, the sources of these 

supply wells would not be physically disturbed by mining activities. Figure 2 in the 2015 

Cumulative Hydrologic Impact Assessment (2015 CHIA; WDEQ-LQD 2015b) shows that clinker 

is present within the Caballo Mine permit area; however, the Caballo West tract contains no 

appreciable clinker deposits and therefore is not addressed in this EA. Active groundwater 

monitoring well locations are depicted on map 3-3.

The 35-year Gillette Area Groundwater Monitoring Organization (GAGMO) report indicates 

that a continuous cone of depression currently exists around the Belle Ayr, Coal Creek, Caballo, 

and Cordero Rojo mines due to their closeness to each other and the cumulative drawdown 

effects from pit dewatering and nearby CBNG discharges (Hydro-Engineering 2016). The finding 

was based on groundwater data collected through 2015 by the coal companies.

Since the publication of the 2009 SGAC EIS, seven new monitoring wells (two alluvial, two 

overburden, two backfill, and one coal) have been completed within the Caballo Mine permit 

boundary and added to the WDEQ-WQD approved groundwater monitoring network. Twelve 

monitoring wells (four overburden, one coal, one backfill, and six alluvial) have been removed 

from the WDEQ-WQD monitoring network since the publication of the 2009 SGAC EIS. The 

removal of these wells resulted from pit advancement and was approved by WDEQ-WQD.

The following discussions on groundwater monitoring was taken from the 2018 Caballo Mine 

Annual Report (PCM 2018b). Table 3-12 provides the most recent and historic total dissolved 

solids (TDS) concentrations from the groundwater monitoring network.

Alluvial Wells – Groundwater in the alluvium exhibited generally declining water levels due to 

a relatively dry spring.

Seven alluvial wells are included in the water quality portion of the Caballo Mine groundwater 

monitoring program. The TDS concentrations from the samples collected in 2017-2018 were 

consistent with historic TDS concentrations. Well NC-0152-A historically has had high TDS 

concentrations. With the exception well NC-0152-A, the water quality in the alluvial wells meets 

WDEQ-WQD Class III livestock standards.

Overburden Wells – Groundwater levels in the overburden wells were generally steady or 

declining. The water level in one well (NC-0062-O) dropped by approximately 30 feet during the 

reporting period for an unknown reason. Two wells (NC-0111-O and NC-0019-O) had 

increasing water levels due to recharge.

Five overburden wells were sampled for water quality during 2017-2018. TDS concentrations 

were consistent with historic concentrations. The water quality in the overburden wells meets 

Class III livestock standards.

Coal Wells – Groundwater levels in the coal were generally stable. One well (NC-0040-C) 

demonstrated declining water levels, although water levels in the well have fluctuated since 1981.

Two coal wells were sampled for water quality during 2017-2018. TDS concentrations were 

consistent with historic concentrations. The water quality in the coal wells meets Class III 

livestock standards.
Chapter 3 – Affected Environment

3-12 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

Map 3-3. Active Groundwater Monitoring Locations and Water Supply Wells at 

the Caballo Mine
Chapter 3 – Affected Environment

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 3-13

Table 3-12. Recent and Historical TDS Concentrations from the Caballo Mine 

Groundwater Monitoring Network

Well

2017-2018

TDS (mg/L)

No. Samples 

Collected to 

Date

Minimum 

TDS (mg/L)

Maximum 

TDS (mg/L)

Mean TDS 

(mg/L)

Alluvial

CA-657-A 3,180 33 2,460 4,092 3,267

CA-660A-A 470 41 168 11,000 3,113

CA-667B-B 3,160 32 1,011 4,190 2,617

CA-791-A 850 42 311 2,960 1,207

NC-0152-A 20,400 37 566 101,900 27,895

NC-0153-A 950 14 3,940 8,552 5,834

NC-0169-A 2,330 29 392 4,035 1,393

Overburden

CA-726-O 2,640 54 2,640 3,800 3,390

CA-758-O 1,220 59 1,140 1,450 1,251

CA-799-O 1,670 27 1,450 1,920 1,683

CA-0111-O 3,590 24 3,582 5,050 4,404

NC-0119-O 940 32 846 1,090 940

Coal

CA-793-C 810 41 570 1,164 777

NC-0018-C 840 34 840 1,090 930

Backfill

CA-1449-B 650 57 590 1,260 713

CA-1539-B 1,300 54 1,035 1,610 1,243

CA-1540-B 1,1130 37 337 2,640 1,604

CA-2233-B 520 27 520 3,670 2,637

CA-2234-B 3,440 38 500 3,770 1,126

CA-724-B 5,080 69 2,690 7,000 5,925

CA-824-B 1,200 75 70 2,440 1,303

Source: PCM 2018b

Backfill Wells – Most of the groundwater levels in the backfill wells have exhibited significant 

resaturation. One well (CA-724-B) has exhibited a slight decline since 2014. Two backfill wells 

(CA-1538-B and CA-1696-B) were dry.

Seven backfill wells were sampled for water quality during 2017-2018. The water quality meets 

Class III livestock standards, with the exception of well CA-724-B, which is located in the backfill 

of the very saline reclaimed North Tisdale Creek alluvium. TDS in all backfills was consistent with 

historic concentrations.

3.5.2 Surface Water

A description of surface water related to the Caballo West tract is provided in section 3.5.2.1 

and section S3-5.2 of the Supplementary Information volume of the 2009 SGAC EIS. The tract is 

located within the Tisdale Creek drainage, a tributary of Caballo Creek. Tisdale Creek drains the 

northern and eastern portions of the tract, and a large playa drains the southern and western 

portions of the tract. Tisdale Creek is currently interrupted to the north of the tract by Caballo 

Mine’s Big Hole Reservoir (a total containment reservoir; State Engineers Office (SEO) Permit 

No. P13451R). Water from Tisdale Creek upstream of the tract is diverted to the reservoir, 

where it is pumped around the mine operations to Gold Mine Draw, another tributary to Caballo 

Creek.
Chapter 3 – Affected Environment

3-14 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

Tisdale Creek and Gold Mine Draw are ephemeral stream channels that are listed in the WDEQWQD Surface Water Classification List as Class 3B streams. Streamflow and surface water quality 

associated with the Caballo Mine are currently monitored at two sites on Gold Mine Draw (map 

3-4). PCM previously operated three surface water monitoring stations on Tisdale Creek. The

Lower Tisdale Creek station was active from 1978 to 1989, the Upper Tisdale Creek station was 

operational from 1979 to 1995, and the Tisdale West station was activefrom 1991 to 2009. The 

Lower and Upper Tisdale Creek stations were discontinued due to pit advancement and the 

Tisdale West station was discontinued due to lack of flow.

Baseline water quality data for Tisdale Creek is provided in the CHIA. The flow data recorded at 

both sites confirmed the ephemeral regime of Tisdale Creek. Flow occurred during only about 4 

percent of the baseline period (1978-1983) at Upper Tisdale and 11 percent of the baseline period 

(1977-1983) at Lower Tisdale. The maximum flows recorded at the Upper Tisdale and Lower 

Tisdale stations were 20.5 cubic feet per second (cfs) and 225 cfs, respectively. A total of 12 

samples were collected at Upper Tisdale Creek and 17 samples at the Lower Tisdale Creek. The 

water type at Upper Tisdale Creek was magnesium sulfate, while the water type at Lower Tisdale 

Creek varied. Few dissolved metals exceeded the WDEQ-WQD Class 3B water quality standard.

The 2015 CHIA also provided data collected on Tisdale Creek from 1984 to when the stations 

were discontinued to characterize during-mining hydrologic conditions. The occasional 

exceedances of Class 3B standards at the lower station appear related to natural factors and are 

not attributable to mining, since the same constituents showed exceedances at the upstream 

station. The 2015 CHIA concluded that there have been no obvious changes in water quality 

conditions over the short period of record on Tisdale Creek.

3.5.3 Water Rights

Section 3.5.3.1 and section S3-5.3 of the Supplementary Information volume of the 2009 SGAC 

EIS provide a detailed discussion of the water rights within and surrounding the Caballo West 

tract.

SEO records indicate that as of February 2019, there were 49 surface-water rights within the 2-

mile search area, of which 42 were owned by coal mining companies and were related to 

industrial, livestock, wetlands, or flood control uses (SEO 2019). Of the other permitted surface 

water rights, four were permitted for livestock, two were permitted for irrigation, and one was 

permitted for livestock and domestic use.

SEO records indicate that, as of February 2019, there were 469 permitted groundwater wells 

within the 2-mile search area, of which 390 are owned by coal mining companies (SEO 2019). 

The other 179 are permitted for the following uses:

• 61 CBNG

• 61 CBNG, Stock

• 2 CBNG, Miscellaneous, Stock

• 16 Domestic

• 8 Domestic, Stock

• 4 Industrial

• 5 Industrial, Miscellaneous

• 4 Miscellaneous

• 1 Miscellaneous, Stock

• 17 Stock
Chapter 3 – Affected Environment

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 3-15

Map 3-4. Surface Water Monitoring Sites at the Caballo Mine
Chapter 3 – Affected Environment

3-16 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

Subcoal aquifers continue to be utilized regionally for municipal, industrial, and domestic water 

supply by the City of Gillette, residential subdivisions, and coal mines.

3.6 Alluvial Valley Floors

Alluvial valley floors (AVFs) within the Caballo West tract are described in section 3.6.1.3 and 

section S3-6 the Supplementary Information volume of the 2009 SGAC EIS. On April 25, 2008, 

the WDEQ-LQD declared that there are no AVF units within the Caballo West tract (PCM 

2014). The only portion of Tisdale Creek determined to be an AVF is at the confluence with Gold 

Mine Draw, approximately 4 miles downstream of the tract.

3.7 Wetlands

As described in section 3.7.1.3 of the 2009 SGAC EIS, a portion of the Caballo West tract within 

the Caballo Mine permit area was previously delineated for wetlands. The information provided 

in the 2009 SGAC EIS on wetlands was based on preliminary wetlands mapping conducted in 

2007 and on a partial wetland delineation. The remaining portion of the tract and an area adjacent 

to the tract have subsequently been surveyed for wetlands (PCM 2014). A formal wetland 

determination was issued by the U.S. Army Corps of Engineers (USACE) in 2010 and reissued by 

the USACE in 2017 (USACE 2010 and USACE 2017). As determined by the USACE, the only 

waters of the U.S within the approved Caballo Mine permit boundary, which includes the Caballo 

West tract, are associated with Gold Mine Draw. This amount differs from 2009 SGAC EIS, which 

indicated approximately 15.0 acres of water of the U.S., including a total of 8.63 acres of 

jurisdictional waters of the U.S. within and adjacent to the Caballo West tract. As a result of the 

2017 reanalysis of potential impacts to jurisdictional wetlands within the permit boundary, the 

USACE determined that agency authorization is not required for coal mining activities at the 

Caballo Mine (USACE 2017).

As shown on map 3-5, there are approximately 1.79 acres of non-jurisdictional aquaticfeatures 

within and adjacent to the tract (PCM 2014). As of March 2018, approximately 0.60 acre of these 

non-jurisdictional aquatic features (open water marsh, wet meadow, and stock pond) have been 

disturbed from mining at the Caballo Mine unrelated to coal recovery within the tract (PCM

2018b).

3.8 Soils

Soils within the Caballo West tract are described in section 3.8.1 and section S3-8 of the 

Supplementary Information volume of the 2009 SGAC EIS. The soil depths and types on the tract 

are similar to soils currently being salvaged and utilized for reclamation at the Caballo Mine.The 

amount of suitable topsoil that would be available for redistribution on all disturbed acres within 

the tract has an average depth of 3.6 feet. No prime farmland was indicated within the tract based 

on a reconnaissance survey by the NRCS (NRCS 2008). As of March 2018, 174.2 acres within 

the tract have been disturbed from mining at the Caballo Mine unrelated to coal recovery within 

the tract (PCM 2018b).

3.9 Vegetation

Vegetation within the Caballo West tract is described in section 3.9.1 and section S3-9 of the 

Supplementary Information volume of the 2009 SGAC EIS. The predominant vegetation types 

within the tract are big sagebrush and cropland. As described above, 174.2 acres within the tract 

have been disturbed from mining at the Caballo Mine unrelated to coal recovery within the tract.
Chapter 3 – Affected Environment

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 3-17

Map 3-5. Wetlands within and Surrounding the Caballo West Tract
Chapter 3 – Affected Environment

3-18 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

3.9.1 Threatened, Endangered, Proposed, and Candidate Plant Species

Plant T&E species were discussed in section 3.9.1 of the 2009 SGAC EIS. The current USFWS 

list of plant T&E species that may occur in Campbell County includes the Ute ladies’-tresses 

(Spiranthes diluvialis) (USFWS 2018a). In 2009 and 2010, surveys for Ute ladies’-tresses were 

conducted on the Caballo Mine permit area and the tract. No Ute ladies’-tresses were identified 

(PCM 2014). In addition, the USFWS has not designated any “critical” habitat for this species in 

the vicinity of the Caballo Mine at this time (USFWS 2018b).

3.10 Wildlife

The occurrence of wildlife related to the mining of the federal coal within the Caballo West tract 

was thoroughly discussed in section 3.10.1 and section S3.10 of the Supplementary Information 

volume of the 2009 SGAC EIS. The information included in the 2009 SGAC EIS was derived from 

the baseline data and the subsequent studies and WDEQ-LQD annual reports. No significant 

changes to wildlife use areas for big game, other mammals, upland game birds (excluding the 

Greater sage-grouse [GRSG] [Centrocercus urophasianus]), other birds, reptiles and amphibians, 

or aquatic species populations have been noted from the previous discussion presented. There 

have been changes in discussions related to raptors; threatened, endangered, and candidate (T&E) 

species; and species of special interest (SOSI). The status of GRSG has also changed since 

publication of the 2009 SGAC EIS. Therefore, these species discussions have been updated in this 

EA.

3.10.1 Raptors

Raptors that could potentially occur in the area include the burrowing owl (Athene cunicularia), 

great horned owl (Bubo virginianus), northern harrier (Circus cyaneus), red-tailed hawk (Buteo 

jamaicensis), Swainson’s hawk (Buteo swainsoni), ferruginous hawk (Buteo regalis), golden eagle 

(Aquila chrysaetos), prairie falcon (Falco mexicanus), short-eared owl (Asio flammeus), bald eagle 

(Haliaeetus luecocephalus), and American kestrel (Falco sparverius) (appendix E).

The 2018 Caballo Mine Annual Report identified the location and annual status of raptor nests 

PCM 2018b). The location and status of raptor nests monitored at the mine are included on map 

3-6. Three intact raptor nests (SH31c1, SH31c2, and RTH16c/SH22b2/FH22) are located within 

the Caballo West tract. One other intact nest (BO3) is within 0.25 mile of the tract. SH31c1 and 

RTH16c/SH22b2/FH22 were active in 2018, producing three Swainson’s hawks and four 

ferruginous hawks, respectively. SH31c2 and RTH16c/SH22b2/FH22 are platform nests erected 

by the PCM for mitigation purposes.

3.10.2 Greater Sage-grouse (GRSG)

EO 2015-4 established GRSG core area protection on state trust lands (Office of the Governor 

2015). The GRSG core area protection concept came about because of work by the Sage-Grouse 

Implementation Team. The implementation team developed a core population strategy for the 

state “to maintain habitats and viable populations of sage-grouse in areas where they are most 

abundant.” As part of that effort, the team delineated approximately 40 areas of state trust lands 

around Wyoming with a goal of maintenance and enhancement of GRSG habitats and populations 

within the core areas. Using mapping included in the EO, it has been determined that the closest 

core area is the Thunder Basin core area, approximately 8.8 miles east of the tract.
Chapter 3 – Affected Environment

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 3-19

Map 3-6. Raptor Nest Sites and Greater Sage-grouse Leks within and Adjacent to 

the Caballo West Tract
Chapter 3 – Affected Environment

3-20 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

According to the BLM Buffalo Field Office (BFO) Resource Management Plan (RMP), the Caballo 

West tract is within a general habitat management area (GHMA) for GRSG (BLM 2015). This 

classification prohibits or restricts surface disturbing and disruptive activities within 0.25 mile of 

the perimeter of occupied GRSG leks. No GRSG leks occur within 0.25 mile of the tract (map

3-6).

Long-term results from annual lek monitoring suggest that the Caballo Mine area only supports 

larger groups of GRSG when regional populations are especially high (PCM 2018b). As indicated 

on map 3-6, six historical GRSG leks have been documented within 4 miles of the tract. The 4-

mile radius of concern represents the area in which two-thirds of the hens that were bred at a lek

would be expected to nest. The Lynde Lek is the only lek within the 4-mile radius that has an 

occupied WGFD management status (active during at least one strutting season within the prior 

10 years). It was last confirmed active in 2009 (WGFD 2018). The remaining five GRSG leks were 

classified with an unoccupied/undetermined WGFD management status. All five leks have been 

inactive since at least 2005.

3.10.3 Vertebrate Threatened, Endangered, and Candidate Species and Species of 

Special Interest

The information presented in this section was obtained from the USFWS’s Information for 

Planning and Conservation (IPaC) system and Natural Resource and Energy Explorer (NREX), 

which is a web GIS-based software tool that supports pre-planning development considerations 

that facilitates the assessment of energy, environmental, cultural, socioeconomic and 

infrastructural assets in Wyoming (NREX 2018).

3.10.3.1 Vertebrate Threatened, Endangered, and Candidate Species

Vertebrate T&E species were discussed in section 3.10.8 of the 2009 SGAC EIS. The current 

USFWS list of vertebrate T&E species that may occur in Campbell County includes the northern 

long-eared bat (Myotis septentrionalis) (USFWS 2018a). The northern long-eared bat has not been 

observed within the Caballo Mine permit area (PCM 2018b). In addition, the USFWS has not 

designated any “critical” habitat for this species in the vicinity of the Caballo Mine at this time 

(USFWS 2018b). The NREX list, which is specific to the Caballo West tract, does not include the 

northern long-eared bat.

Although USFWS information indicates that the northern long-eared bat could occur in the area, 

habitat (caves and mine shafts as winter habitat and caves, mine shafts, and trees for summer 

habitat; USFWS 2016) is not present in the tract to support the threatened bat. No northern 

long-eared bat populations have been documented within Campbell County but a small portion 

of the tract (20.1 acres) is the area of influence (AOI) for the northern long-eared bat (USFWS 

2018a). In addition, the USFWS identified the counties within 150 miles of the boundaries of the

U.S. counties or Canadian districts where white noise syndrome (WNS) or its causative fungus 

Pseudogymnoascus destructans have been detected (USFWS 2019a). Campbell County lies within 

the WNS zone.

3.10.3.2 Species of Special Interest

NREX information was utilized for the determination of SOSI species that could occur in the 

area. For the purposes of this discussion, SOSI include BLM sensitive species, Wyoming Natural 

Diversity Database (WYNDD) species of concern (SOC), species protected under the MBTA, 

and WGFD species of greatest conservation need (SGCN). USFWS T&E species are not included
Chapter 3 – Affected Environment

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 3-21

in this category. There is a considerable amount of crossover between the species occurrence 

on the various lists included in SOSI (appendix E). BLM sensitive species include those species 

listed or proposed for listing under the ESA together with species designated internally as BLM 

sensitive in accordance with BLM Manual 6840 (BLM 2008). WYNDD has developed a list of 

SOC in Wyoming that are rare, endemic, disjunct, threatened, or otherwise biologically sensitive, 

and supporting documentation. The MBTA makes it illegal to take, possess, import, export, 

transport, sell, purchase, barter, or offer for sale, purchase, or barter, any migratory bird, orthe 

parts, nests, or eggs of such a bird except under the terms of a valid federal permit. WGFD 

SGCN include wildlife species with low and declining populations that are indicative of the 

diversity and health of Wyoming’s wildlife (WGFD 2019). The WGFD’s SGCN designation 

process is based upon its Native Species Status (NSS) classification system. The WGFD places 

each SGCN into one of three tiers of management based on its total score: Tier I (highest 

priority), Tier II (moderate priority), or Tier III (lowest priority).

As determined from the NREX list, 50 terrestrial-vertebrate SOSI have the potential of occurring 

within the Caballo West tract. As shown in appendix E, 46 WGFD SGCN, 33 species protected 

under the MBTA, 17 WYNDD SOC, 14 BLM sensitive species, and 2 WGFD-designated Tier I 

terrestrial-vertebrate species have the potential of occurring within the Caballo West tract. 

According to wildlife monitoring results, 27 of these SOSI have been confirmed as occurring 

within or adjacent to the tract during baseline or annual monitoring. Twelve of the BLM sensitive 

species and 13 of the WYNDD birds of concern have been observed during wildlife surveys 

within the tract. Both of the WGFD designated Tier I species (burrowing owl and mountain 

plover [Charadrius montanus]) have been observed within the tract.

3.11 Land Use and Recreation

Land use and recreation on the Caballo West tract is described in section 3.11.1 and section

S3-11 of the Supplementary Information volume of the 2009 SGAC EIS. All of the surface estate 

on the tract is privately owned by PCM. Livestock grazing, oil and gas production, wildlife habitat, 

and recreation are the primary land uses.

3.12 Cultural Resources

Information regarding background cultural resources was included in section 3.12.1.3 and section 

S3-12 of the Supplementary Information volume of the 2009 SGAC EIS. A portion ofthe Caballo 

West tract and surrounding area had been surveyed for cultural resources at a Class III level. 

According to information provided in the 2009 SGAC EIS, seven cultural sites (five prehistoric, 

one historic, and one multi-component)were located within the Caballo West tract survey area. 

Four of the cultural sites (48CA5232, 48CA5324, 48CA503, and 48CA2706) were located within 

the Caballo West tract. All four sites were considered not eligible for listing on the National 

Register of Historic Places (NRHP; Wyoming State Historic Preservation Office 2012, OSMRE 

2003, WDEQ-LQD 2013). A Class III cultural resource survey that included the remaining 

portion of the Caballo West tract and an area southwest of the tract was conducted in 2010 

(PCM 2014). The Class III inventory identified one historic homesteading location, three 

prehistoric isolated finds, and two previously recorded cultural properties. A prehistoric isolated 

find is defined by the Wyoming State Historic Preservation Office (2019) as 14 or fewer spatially 

associated artifacts where no buried cultural materials or features are thought to exist. No 

mitigation measures are necessary for isolated finds. The historic homesteading location was 

considered not eligible for listing on the NHRP (OSMRE 2012).
Chapter 3 – Affected Environment

3-22 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

3.13 Visual Resources

Visual resources on the Caballo West tract are described in section 3.13.1 of the 2009 SGAC 

EIS. According to the most recent BLM BFO RMP, the Caballo West tract is within visual resource 

management Class IV (BLM 2015). The objective of Class IV is to provide for management 

activities that require major modification of the existing character of the landscape. Currently, 

mine facilities and mining activities at the Caballo Mine are visible from State Highway 59 and 

Bishop Road.

3.14 Noise

Noise on the Caballo West tract is described in section 3.14.1 of the 2009 SGAC EIS. Existing 

noise sources in the tract vicinity include coal mining activities, rail traffic, traffic on the nearby 

state highway, county and access roads, natural gas compressor stations, and wind. According to 

the 2009 SGAC EIS, the current median noise level near mining is estimated to be 40-60 dBA for 

day and night, with the noise level increasing with proximity to active mining operations at the 

adjacent mine. The 2009 SGAC EIS describes a noise study conducted at Cordero-Rojo Mine in 

2004 that found that all blasting events were in compliance with OSMRE safe blasting levels. The 

nearest occupied residence to the Caballo West tract is approximately 3,200 feet to the west 

(map 1-2).

3.15 Transportation

Transportation in the vicinity of the Caballo West tract is described in section 3.15.1 of the 2009 

SGAC EIS. Major roads and railroads in the general area of the tract include State Highway 59 and 

Bishop Road. Existing transportation facilities include roads, railroads, coal conveyors, and 

overhead electrical transmission lines associated with the Caballo Mine. All coal mined at the 

Caballo Mine is transported by rail (BNSF trackage).

3.16 Hazardous and Solid Waste

Hazardous and solid waste on the Caballo West tract is described in section 3.16.1 of the 2009 

SGAC EIS. Potential sources of hazardous or solid waste on the tract include spilled, leaked, or 

dumped hazardous substances, petroleum products, and/or solid waste associated with coal and 

oil and gas exploration, oil and gas development, utility line installation and maintenance, or 

agricultural activities.

3.17 Socioeconomics

This section describes existing socioeconomic conditions in Wyoming and Campbell County 

specific to the state and local economy, population, and employment. The discussions included in 

section 3.17 of the 2009 SGAC described socioeconomic conditions associated with the Caballo 

Mine in 2009. Discussions related to housing, local government services, and environmental 

justice have not changed enough to require reevaluation in this EA. The following includes 

updated discussions on the local economy, population, and employment.

3.17.1 State and Local Economy

Wyoming’s coal mines (surface and underground) produced an estimated 316.6 Mt of coal in 

2017, a decrease of about 149.7 Mt (32 percent) from the record 466.3 Mt produced in 2008 but 

more than the 297.5 Mt produced in 2016 (WDWS 2008, 2016, 2017). Coal produced from 14

active mines in Campbell County, which makes up approximately 5 percent of the surface area of

Wyoming, accounted for approximately 97 percent of total statewide coal production in 2017
Chapter 3 – Affected Environment

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 3-23

(WDWS 2017). According to coal production numbers from the U.S. Energy Information 

Administration (EIA), the coal from Campbell County accounted for approximately 44 percent 

of the coal produced in the U.S. in 2017 (EIA 2017).

The estimated total fiscal impact from coal production in Campbell County to the State of 

Wyoming in 2018 was calculated based on coal produced from the county in 2017. The sale of 

coal from Campbell County in 2017 resulted in an estimated $457,591,386 of federal revenues 

and $649,266,546 in state revenues, for a total of $1,106.9 million, or $3.50 per ton (see 

appendix D for calculations).

3.17.2 Population

In 2017, Campbell County had a population of 46,242, which ranked it as the third most populous 

of Wyoming’s 23 counties (U.S. Census Bureau [USCB] 2018). The majority of the Campbell 

County mine employees and support services reside in Gillette. It is estimated that the total 

population in the Gillette city limits increased from 29,947 in 2010 to 30,560 in July 2017, an 

increase of 2.0 percent over the period (USCB 2018). Table 3-13 presents the population 

changes for Campbell County and Gillette. As of July 2017, Gillette accounted for roughly 66.1 

percent of the county’s residents. Gillette was the fourth largest city in the state, following 

Cheyenne, Casper, and Laramie (USCB 2018).

Table 3-13. Campbell County and City of Gillette Population Change, 2010-2017

2010 2011 2012 2013 2014 2015 2016 2017 2010-2017

Increase

2010-2017

Percent 

Change

Campbell County 46,233 46,600 47,881 48,121 48,243 49,220 48,800 46,242 9 0.02

City of Gillette 29,947 30,432 31,423 31,732 31,920 32,649 32,290 30,560 613 2.05

Source: USCB 2018

Table 3-14 presents the employment changes for Wyoming and Campbell County for 2011-

2017. The statewide total employment increased by 3,284 jobs (1.1 percent), while the Campbell 

County employment increased by only 5 jobs (0.02 percent) during the same time period. The

average unemployment rate in Campbell County decreased from 4.9 percent in 2011 to 4.1 

percent in 2017 (U.S. Bureau of Labor Statistics 2018).

Table 3-14. Wyoming and Campbell County Employment Rate Change, 2011-2017

2011 2012 2013 2014 2015 Dec 

2016

Dec 

2017

Wyoming (Number Employed) 289,019 291,076 292,157 294,207 293,262 300,872 292,303

Wyoming (Number Unemployed) 17,796 16,349 14,414 12,726 12,750 14,539 12,345

Wyoming Unemployment Rate 5.8 5.3 4.7 4.1 4.2 4.8 4.2

Campbell County (Number Employed) 24,605 24,919 24,609 25,423 24,943 23,921 24,610

Campbell County (Number Unemployed) 1,267 1,213 1,087 882 987 1,446 936

Campbell County Unemployment Rate 4.9 4.6 4.2 3.4 3.8 6.2 4.1

Source: U.S. Bureau of Labor Statistics 2018

Employment in mining bottomed out in the third quarter of 2016, with slightly fewer than 18,000 

jobs, the lowest level in more than 10 years. Since then, however, mining has seen over-themonth increases in each of the 6 months prior to the base period (2017Q2). Wyoming’s 

employment is expected to grow by 7,333 jobs (2.7 percent) from the second quarter of 2017 

to second quarter of 2019, with job growth forecast for all sectors. The largest job growth is 

expected in mining, including oil and gas, at 2,410 jobs (12.5 percent), due to favorable oil prices 

(WDWS 2018).

Chapter 4 – Environmental Consequences/Cumulative Impacts

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 4-1

4.0 Environmental Consequences/Cumulative Impacts

4.1 Introduction

This chapter discusses the potential direct, indirect, and cumulative effects of the Proposed 

Action and the No Action Alternative, as described in chapter 2. The discussion is organized by 

resource areas in the same order as they are described in chapter 3.

An impact, or effect, is defined as a modification to the environment brought about by an outside 

action. Impacts vary in significance from no change, or only slightly discernible change, to a full 

modification or elimination of the resource. 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: Impacts that potentially could cause significant depletion, change, or stress to 

resources or stress within the social, cultural, and economic realm.

• Moderate: Impacts that potentially could cause some change or stress to an 

environmental resource but the impact levels are not considered significant.

• Minor: Impacts that potentially could be detectable but slight.

• Negligible: Impacts in the lower limit of detection that potentially could cause an 

insignificant change or stress to an environmental resource or use.

• No Effect/Impact: No discernible or measurable impacts.

Impacts can also be defined as direct, indirect, or cumulative. Terminology presented in this 

analysis includes the following:

• Direct impacts are defined as those impacts which are caused by the action and occur at 

the same time and place (40 CFR § 1508.8(a)).

• Indirect impacts are those that are caused by the action and occur later in time or are 

farther removed in distance but are still reasonably foreseeable (40 CFR § 1508.8(b)).

• Cumulative impacts are those impacts that result from incremental effects of an action 

when added to other past, present, and reasonably foreseeable future actions regardless 

of what agency or other entity undertakes such other actions (40 CFR § 1508.7). 

Cumulative impacts occur over a given time period when the impacts of past, present, 

and reasonably foreseeable future actions overlap with the time period when project 

impacts would occur (including the coal recovery and reclamation phases).

The duration of impacts is also presented throughout this chapter, as follows:

• Short-term impacts generally occur over a short period and revert to pre-disturbance 

conditions within a few years after mining occurs.

• Long-term impacts are defined as those that would remain beyond mining-related 

activities (including reclamation), generally, lasting the life the alternative being evaluated 

(e.g., federal mining plan modification approval) and beyond.

The direct, indirect, and cumulative effects of the Proposed Action and No Action Alternative 

are comparable to those described in the 2009 SGAC EIS, except as noted herein. In addition to 

addressing the specific issues identified in chapter 1, this updated environmental consequences 

analysis reflect updated descriptions of the affected environment presented in chapter 3 that 

have taken place since the 2009 SGAC EIS.
Chapter 4 – Environmental Consequences/Cumulative Impacts

4-2 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

The environmental and cumulative effects discussions below assume that under the Proposed 

Action, the federal mining plan modification to mine coal in the Caballo West tract would be 

approved. Coal recovery is projected to continue within the Caballo Mine permit area at an 

estimated annual rate of 13.5 Mt, which is consistent with the 2015-2017 average annual recovery 

rate. The recovery of the remaining federal coal would continue for approximately 8.9 additional 

years over the No Action Alternative. New mine facilities, associated surface disturbances, and 

subsidence repairs would not be required in connection with the ProposedAction.

Under the No Action Alternative, the mining plan modification to allow mining of the federal coal 

within the Caballo West tract would not be approved. Currently approved mining operations 

associated with federal coal would continue for approximately 24 years within existing federal 

leases, at a rate of approximately 13.5 Mtpy. The disturbance would be similar to those under 

the Proposed Action although the impacts to approximately 866.7 acres to recover federal coal 

within the tract would not occur.

Cumulative effects discussed in this chapter consider the other activities and processes in the 

area. The mines included in the cumulative effects analysis include the Caballo, Belle Ayr, Cordero 

Rojo, and Coal Creek mines, herein referred to as the central group of mines. These mines are 

depicted on map 1-1.

4.2 Topography and Physiography

4.2.1 Direct and Indirect Effects

4.2.1.1 Proposed Action

The direct and indirect effects to topography and physiography would not be significantly different 

from those described in section 3.2.2.1 of the 2009 SGAC EIS. The Proposed Action would impact 

the topography and physiography of the Caballo West tract, but these impacts would be similar 

to those currently occurring at the Caballo Mine. After mined-out areas are reclaimed, the land 

surfaces would be gentler, with more uniform slopes and restored basic drainage networks. The

direct effects on topography and physiography resulting from the Proposed Action would be 

moderate and permanent. There would be no indirect effects under the Proposed Action.

4.2.1.2 No Action Alternative

The impacts to topography under the No Action Alternative would be similar to those under the 

Proposed Action although the impacts to approximately 866.7 acres to recover federal coal 

within the Caballo West tract would not occur.

4.2.2 Cumulative Effects

The cumulative impacts to topography and physiography would not be significantly different than 

those described in section 4.2.1 of the 2009 SGAC EIS. The cumulative effects would primarily 

be related to the central group of mines. Following surface coal mining and reclamation, 

topography would be modified within the permit boundary of these mines. The cumulative effects 

on topography and physiography are expected to be moderate and permanent.

4.2.3 Mitigation Measures

No mitigation measures would be necessary for topography and physiography.
Chapter 4 – Environmental Consequences/Cumulative Impacts

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 4-3

4.3 Geology, Mineral Resources, andPaleontology

4.3.1 Direct and Indirect Effects

4.3.1.1 Proposed Action

The direct and indirect effects to geology would not be different than those described in section

3.3.1.2.1 of the 2009 SGAC EIS. Under the Proposed Action, the stratigraphic units from the base

of the lowest coal seam mined to the land surface would be subject to permanent change after the

coal is removed. As a result, the physical characteristics of the backfill would be different from the 

physical characteristics of the existing layered overburden stratigraphy. The Proposed Action

would result in the recovery of approximately 119.8 Mt of federal coal within the Wyodak coal

seam. The direct and indirect effects on geology are expected to be moderate and permanent on 

the Caballo West tract.

The direct and indirect effects to other mineral resources would not be different than those 

described in section 3.3.2.2.1 of the 2009 SGAC EIS. CBNG wells located on the tract would be 

abandoned and mined through as mining progresses. The direct effects on CBNG resources 

resulting from the Proposed Action would be moderate and permanent on the tract due to the 

loss of any remaining CBNG within the Wyodak coal seam. The effects would be minor and 

short-term for conventional oil and gas due to the surface disturbance that could prohibit 

recovery of the resource.

The direct and indirect effects to paleontology would not be different than those described in 

section 3.3.3.2.1 of the 2009 SGAC EIS. Fossils with scientific significance could be present on the 

tract but not exposed at the surface. Should previously unknown, potentially significant 

paleontological sites be discovered, BLM imposed lease and permit conditions thatrequire work 

in that area stop and measures be taken to assess and protect the site. The effects on 

paleontological resources resulting from the Proposed Action would be moderate and 

permanent.

4.3.1.2 No Action Alternative

Impacts to the geological resources have resulted from current mining activity on adjacent lands 

and therefore under this alternative, impacts to geological resources in the area would be similar 

to those under the Proposed Action. Impacts to the geological and paleontological resources, 

excluding CBNG, would be approximately 866.7 acres less than the Proposed Action. Impacts to 

CBNG resources would be moderate and permanent as a result of mining activities on adjacent 

lands.

4.3.2 Cumulative Effects

The cumulative impacts to geology, mineral resources, and paleontology would not be different 

than those described in section 4.2.2 of the 2009 SGAC EIS. Within the central group of mines, 

overburden and coal would be removed and replaced with backfill, resulting in a permanent 

change in the geology of the area and a permanent reduction of coal resources.

According to information from the WOGCC (2019), 20,897 CBNG wells have been drilled in 

Campbell County. The WOGCC records indicate that a majority of the wells are privately held 

or state minerals, with approximately 37.1 percent of the wells (7,758) being federal minerals. 

Status of these wells includes plugged and abandoned, dormant, completed, monitoring and notice 

of intent to abandon. In 2018, only 3,845 CBNG wells in Campbell County were producing.
Chapter 4 – Environmental Consequences/Cumulative Impacts

4-4 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

Impacts to paleontological resources as a result of the already-approved cumulative energy 

development occurring in the PRB consist of losses of plant, invertebrate, and vertebrate fossil 

material for scientific research, public education (interpretive programs), and other values. Losses 

of paleontological resources would continue to result from the destruction, disturbance, or 

removal of fossil materials from surface-disturbing activities, as well as unauthorized collection 

and vandalism. A beneficial impact of surface mining would be the exposure of fossil materials for 

scientific examination and collection, which might never occur except as a result of overburden 

removal, exposure of rock strata, and mineral excavation.

The cumulative effects on the geology, mineral resources, and paleontology are expected be 

moderate and permanent.

4.3.3 Mitigation Measures

No mitigation measures would be necessary for geology or mineral resources. Should significant 

paleontological resources be encountered as a result of the Proposed Action, the appropriate 

agencies would be consulted.

4.4 Air Quality and Climate Change

4.4.1 Particulate Matter

4.4.1.1 Direct and Indirect Effects

4.4.1.1.1 Proposed Action

The direct and indirect effects to air quality from particulate matter would not be different than 

those described in section 3.4.2.2.1.3 of the 2009 SGAC EIS. Direct emissions from particulate 

matter from the Proposed Action would include fugitive emissions generated from coal 

excavation and reclamation activities and tailpipe emissions from equipment. Fugitive particulate 

emissions would also result from dust being generated during dragline operation, coal haulage, 

bulldozers, scrapers, loaders, baghouse, and other equipment operating at Caballo Mine. The 

Caballo Mine triennial emission inventory for 2017 was used to estimate direct particulate matter 

emissions for the Proposed Action. Particulate matter emissions for the Proposed Action and 

the State of Wyoming are tabulated in table 4-1.

Table 4-1. Comparison of Direct to Wyoming Particulate Matter Emissions

Proposed Action (tons)

2017 Wyoming State

Tier 1 (tons)

Anticipated % change 

to State Emissions from 

Proposed Action

PM2.5 90 38,115 0.2

PM10 585 195,180 0.3

Source: PCM 2017, EPA 2019g

The most recent air quality modeling for the Caballo mine was completed in 2006 and described 

in the 2009 SGAC EIS. While not current, the modeling conducted in 2006 provides sufficient 

information for the assessment of impacts because mining methods have not changed and the 

projected annual production is less than the annual production used in the 2006 modeling. PCM 

is currently working on an air quality model, which is expected to be completed late-2019.

The 2006 PM10 inventory for the mining activities at Caballo Mine was prepared for years 2006 

through 2023. Two years were then selected for worst-case dispersion modeling of PM10 based 

on mine plan parameters and emission inventories. As described in the 2009 SGAC EIS, fugitive
Chapter 4 – Environmental Consequences/Cumulative Impacts

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 4-5

emission sources and point sources were modeled using the Industrial Source Complex 3 LongTerm (ISCLT3) dispersion model, which is the model recommended by WDEQ guidance.

As described in the 2009 SGAC EIS, worst-case years for evaluation were based on the highest 

modeled PM10 concentrations. The 2006 ISCLT3 model predicted no exceedances of the annual 

PM10 ambient air standard at a 50 Mtpy production rate. At the estimated average annual 

production rate of 13.5 Mt the particulate matter emissions from the Proposed Action would 

likely be less than those than those predicted in the model, since the annual production would 

be less than used in the model. The direct and indirect effects from particulate matter emissions 

resulting from the Proposed Action are expected to minor compared to Wyoming state 

particulate emissions and moderate and short-term on the tract because modeled particulate 

matter emissions would be below the NAAQS and WAAQS thresholds. The effects of particulate 

matter emissions from coal combustion are included in section 4.4.5.

4.4.1.1.2 No Action Alternative

Impacts from particulate matter emissions have resulted from current mining activity and 

therefore under this alternative, particulate matter emission impacts in the area would be similar 

to those under the Proposed Action but would not be extended for an additional 8.9 years.

4.4.1.2 Cumulative Effects

The locations of PM10 and PM2.5 emission monitoring samplers within the central group of mines 

are depicted on map 3-1. Monitoring during the 2010-2017 period demonstrated that ambient 

concentrations of PM10 were within established short-term (24-hour) presented in table 4-2. 

During this period, no exceedances of the PM10 standards were reported.

Table 4-2. PM10 Concentration Values (24-Hr, First Maximum Value - μg/m3) for 

2010-2017

Location/Site Name/AQS Site ID1 2010 2011 2012 2013 2014 2015 2016 2017

South Campbell County/Campbell County/56-005-0456 36 41 71 39 52 135 63 113

Belle Ayr/BA-1/56-005-0802 29 51 45 27 28 49 44 71

Belle Ayr/BA-3/56-005-0893 31 46 48 34 38 52 27 105

Belle Ayr/BA-4/56-005-0892 55 69 54 39 43 66 38 71

Caballo/C-8A/B/56-005-0886 122 98 99 84 55 80 52 131

Caballo/C-9/56-005-0908 67 69 76 64 54 72 76 117

Coal Creek/CCM 7-1/56-005-0841 26 32 45 30 21 51 20 38

Coal Creek/Site 26/56-005-0890 44 38 49 **   **  **

Coal Creek/Site 3/56-005-0303   65 56 39 51 31 89

Cordero/CRC-E10A/56-005-0885 66 83 108 68 67 88 52 98

Cordero Rojo/Caballo Mine-W11 Hilight Road/56-005-1003 **  66 63 55 60 51 35 96

Cordero Rojo/Site W/56-005-0883 83 53 **   **  ** **

Cordero/Hv-3/PM-3/56-005-0889 54 27   **  **   1 See map 3-1 for site locations.

**  Indicates that the site was inactive. 

Source: EPA 2019d

In 2014, McVehil-Monnett Associates, Inc. (McVehil-Monnett) conducted air quality modeling for 

the Belle Ayr Mine, located immediately adjacent (south) of the Caballo Mine, using the ISCLT3 

model. The model evaluated overall maximum PM10 emissions for years 2014-2031 resulting from 

mining activities at the central group of mines (McVehil-Monnett 2014). Redhorse Corporation 

(Redhorse) also conducted air quality modeling in 2016 for the Cordero Rojo Mine located south
Chapter 4 – Environmental Consequences/Cumulative Impacts

4-6 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

of the Belle Ayr Mine. Redhorse also used the ISCLT3 model to estimate average annual PM10 

concentrations for years 2016-2035, for the central group of mines (Redhorse 2016). Based on 

mine plan parameters and highest emissions inventories, the years 2017 and 2023 were selected 

as the worst-case years for evaluation, since those years had the highest modeled PM10 

concentrations.

The results of the modeling are included in table 4-3. Both models predicted no future 

exceedances of the annual PM10 WAAQS or NAAQS for the combined emissions at the central 

group of mines (McVehil-Monnett 2014 and Redhorse 2016). Based on the information included 

in section 3.4.1.1, the Caballo Mine would not cause or contribute to a violation of the federal 

24-hour PM10 NAAQS of 150 μg/m3.

Table 4-3. McVehil-Monnett and Redhorse Annual PM10 and NO2 Dispersion 

Modeling Results

Pollutant

Modeled 

Concentration 

(μg/m3)

Background 

Concentration 

(μg/m3)

Total 

Concentration1 

(μg/m3)

NAAQS/ 

WAAQS

(μg/m3)

McVehil-Monnett

2016 Mine Year

PM10 36.78 9.00 45.78 502

NO2 34.94 14.00 48.94 100

2017 Mine Year

PM10 34.47 9.00 43.97 502

NO2 31.99 14.00 45.99 100

Redhorse

2017 Mine Year

PM10 26.06 9.50 35.56 502

NO2 30.67 20.00 50.67 100

2023 Mine Year

PM10 15.58 9.50 25.08 502

NO2 23.18 20.00 43.18 100 1 The total includes modeled concentrations for the Belle Ayr, Caballo, Coal Creek, and Cordero Rojo mines plus background.

2 WAAQS standard only (no annual standard for NAAQS). Violation occurs with more than one expected exceedance per calendar year. 

Source: McVehil-Monnett 2014 and Redhorse 2016

The cumulative effects from particulate matter emissions are expected to be moderate and shortterm because modeled PM10 emissions would be below NAAQS and WAAQS thresholds and 

would be extended by approximately 8.9 years.

4.4.1.3 Mitigation Measures

No mitigation measures beyond those required by the Caballo Mine air quality permit would be 

required for emissions of particulate matter.

4.4.2 Emissions of Nitrogen Oxides (NOX) and Ozone (O3)

4.4.2.1 Direct and Indirect Effects

4.4.2.1.1 Proposed Action

Direct emissions from NOx from the Proposed Action would include emissions generated from 

coal excavation and reclamation activities, tailpipe emissions from equipment, and fugitive 

emissions. The Caballo Mine triennial emission inventory for 2017 was used to estimate direct 

NOx emissions for the Proposed Action. NOx emissions for the Proposed Action and the State 

of Wyoming are tabulated in table 4-4.
Chapter 4 – Environmental Consequences/Cumulative Impacts

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 4-7

Table 4-4. Comparison of Direct to Wyoming NOx Emissions

Proposed Action (tons)

2017 Wyoming State

Tier 1 (tons)

Anticipated % change 

to State Emissions from 

Proposed Action

NOx 484 144,241 0.3

Source: PCM 2017, EPA 2019g

Compared to total Wyoming state emissions the direct NOx emissions from the Proposed Action 

would be minor.

As presented in table 3-4, NO2 data collected at the currently active AQS monitoring sites in 

Campbell County nearest to the Caballo Mine were below the NAAQS and WAAQS, which 

indicates that ambient air quality within the vicinity of the Caballo West tract is currently in 

compliance for the NO2.

Caballo Mine included modeled results for NOX emissions for 2006 through 2023 as a part of the

MD-1125 air quality permit in 2006, as described in section 3.4.3.1.1.3 of the 2009 SGAC EIS. NOX 

emission rates for the 2008 and 2014 were estimated to be 1,597 tons per year (tpy) and 1,830 

tpy, respectively. The 2006 ISCLT3 model predicted no exceedances of the NOX ambient air 

standards at a 50 Mtpy production rate. At the estimated average annual production rate of

13.5 Mt the NOX emissions from the Proposed Action would likely be less than those than those 

predicted in the model, because the annual production would be less than used in the model. The 

direct and indirect effects from NOX emissions resulting from the Proposed Action are expected 

to be moderate and short-term on the tract because modeled NOX emissions would be below 

the NAAQS and WAAQS thresholds.

Public exposure to NOX emissions caused by surface mining operations is most likely to occur 

along publicly accessible roads and highways that pass through the area of the mining operations. 

Occupants of residences in the area could also be affected. The closest public transportation 

route is Bishop Road, which runs through a portion of the tract, and the nearest occupied 

residence is approximately 3,200 feet east of the tract. There have been no reported events of 

public exposure to NO2 from blasting activities at the Caballo Mine through December 2018 

(Barney 2019).

As indicated in section 3.4.1.2, O3 monitoring is not required by WDEQ-AQD at PRB mines,

but levels have been monitored at AQS monitoring sites in Campbell County since 2001. No 

violations of the 8-hour O3 NAAQS have occurred.

As stated above, there have been no reported events of public exposure to NO2 from blasting 

activities at the Caballo Mine through December 2018 and there have been no violations of the 

NO2 or O3 ambient air standards in Campbell County. Under the Proposed Action, coal recovery 

at the Caballo Mine would continue at an estimated annual rate of 13.5 Mt, which is less than the 

annual production rate that was used for modeling NOx. While the results from ongoing 

monitoring show no violations of NOX or O3 NAAQS or WAAQS standards in Campbell County, 

the slight potential for exposure to NOX and O3 emissions suggests that the direct and indirect 

effects from emissions resulting from the Proposed Action would be moderate for NOX and 

minor for O3. The effects would be short-term.
Chapter 4 – Environmental Consequences/Cumulative Impacts

4-8 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

4.4.2.1.2 No Action Alternative

Impacts from NOX and O3 emissions have resulted from current mining activity and therefore the 

impacts related to NOX and O3 emissions under the No Action Alternative would be similar to 

those under the Proposed Action but would not be extended for an additional 8.9 years.

4.4.2.2 Cumulative Effects

The central group of mines would contribute cumulative NOX and O3 emissions to the 

surrounding area. NOX modeling conducted for the current Belle Ayr and Cordero Rojo air 

quality permits each included the effects from the central group of mines. The models predicted 

that mining activities at the central group of mines would not contribute to a violation of the NO2 

NAAQS or WAAQS (McVehil-Monnett 2014 and Redhorse 2016). Cumulative impacts from 

NOX could be higher in the short-term (8.9 years) in this area due to coal mining activities if 

surface inversion occurs in the northern portion of the PRB. This would be temporary, lasting 

only during the inversion. NOX impacts would cease to occur after mining and reclamation are 

complete. As previously discussed, no exceedances of the O3 standard have occurred at the AQS 

monitoring sites in Campbell County. Therefore, the cumulative effects from NOX and O3 

emissions would be moderate and short-term.

4.4.2.3 Mitigation Measures

No mitigation measures beyond those required by the Caballo Mine air quality permit would be 

required for emissions of NOX or O3.

4.4.3 Emissions of Sulfur Dioxide (SO2), Mercury (Hg), Lead (Pb), and Other NonGreenhouse Gases (Non-GHG)

4.4.3.1 Direct and Indirect Effects

4.4.3.1.1 Proposed Action

Direct air emissions for SO2, Hg, Pb, and other non-GHG from the Proposed Action would 

include emissions generated from coal excavation and reclamation activities and tailpipe emissions 

from equipment. The Caballo Mine triennial emission inventory for 2017 was used to estimate 

direct SO2, Hg, Pb, and other non-GHG emissions for the Proposed Action. SO2, Hg, Pb, and 

other non-GHG emissions for the Proposed Action and the State of Wyoming are tabulated in 

table 4-5.

In addition, data presented in section 3.4.1.2 show that SO2, Hg, and Pb in Campbell County 

are in compliance with applicable standards. Under the Proposed Action, coal at Caballo Mine 

would be produced at an estimated annual rate of 13.5 Mt. Because the direct emissions fromthe 

Proposed Action would be minor when compared to Wyoming state emissions and given the 

results of ongoing SO2, Hg, and Pb monitoring in the area that show no exceedances of these

parameters, the effects of emissions of SO2, Hg, Pb, and other non-GHGs from the Proposed 

Action would be minor and short-term.
Chapter 4 – Environmental Consequences/Cumulative Impacts

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 4-9

Table 4-5. Comparison of Direct to Wyoming SO2, Hg, Pb and Other Non-GHG 

Emissions

Source

Proposed Action 

(tons)

2017 Wyoming State

Tier 1 (tons)

Anticipated % change 

to State Emissions from 

Proposed Action

VOC 21.87 271,481 0.01

HCOH 0.02 NA -

CO 127.76 250,232 0.05

SO2 36.34 52,354 0.1

Benzene 0.03 NA -

Toluene 0.02 NA -

Ethyl-Benzene 0.001 NA -

Xylene 0.01 NA -

N-Hexane 0.05 NA -

Lead 0.00001 NA -

Mercury 0.00001 NA -

Other HAPs 0.07 NA -

Total HAPs 0.19 NA - NA – Not available

Source: PCM 2017, EPA 2019g

4.4.3.1.2 No Action Alternative

Impacts from SO2, Hg, and Pb emissions have resulted from current mining activity, and, therefore,

the impacts related to SO2, Hg, or Pb emissions under the No Action Alternative would be similar 

to those under the Proposed Action but would not be extended for an additional 8.9 years.

4.4.3.2 Cumulative Effects

The adjacent central group of mines would contribute additional SO2, Hg, and Pb emissions to 

the surrounding area. Based on past monitoring, the permit modification request would not likely 

increase SO2, Hg, or Pb emissions. While cumulative impacts from SO2, Hg, or Pb could be higher 

in the short-term in this area due to coal mining activities if surface inversion occurs in the 

northern portion of the PRB, this would be temporary, lasting only during periods of inversions. 

Air quality impacts from mining would cease to occur after reclamation is complete. Therefore, 

the cumulative effects from SO2, Hg, and Pb emissions are expected to be minor and short-term.

4.4.3.3 Mitigation Measures

No mitigation measures beyond those required by the Caballo Mine air quality permit would be 

required for emissions of SO2, Hg, or Pb.

4.4.4 Air Quality Related Values (AQRVs)

4.4.4.1 Direct and Indirect Effects

4.4.4.1.1 Proposed Action

Visibility

WDEQ-LQD has determined that the Caballo Mine is not a major stationary source, in 

accordance with Chapter 6, Section 4 of the Wyoming Air Quality Standards and Regulations. 

Therefore, the State of Wyoming does not require mines to evaluate impacts on Class I areas;
Chapter 4 – Environmental Consequences/Cumulative Impacts

4-10 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

however, OSMRE considers such issues during the federal mining plan modification review 

process.

Although overburden is generally thicker in the tract, compared to other lease areas currently 

being mined, emissions from blasting are not expected to increase under the Proposed Action 

but the duration of potential impacts from blasting would be extended. All blasting would be 

conducted in compliance will all applicable local, state, and federal laws and regulations, including 

WDEQ-LQD Rules and Regulations, Chapter 6. All blasting operations are conducted underthe 

direction of a certified blaster. The direct and indirect effects to visibility from blasting under the 

Proposed Action would be moderate and short-term because pollutants and particulatesthat effect 

visibility would be within the approved air quality permit MD-1477.

Because WDEQ-LQD does not require the Caballo Mine to evaluate visibility impacts on Class I 

areas, the mine does not monitor visibility. Therefore, a direct comparison with the Wyoming 

standards is not possible. The impacts to visibility from mining the Caballo West tract have been 

inferred from the long-term trend in visibility at the Wind Cave National Park. Because the longterm visibility has been stable, the indirect effects on visibility from the Proposed Action would 

be minor and short-term.

Air Quality Related Values Related to Coal Combustion

Emissions that affect air quality also result from combustion of fossil fuels. Table 4-6 presents 

the estimated 2018-2051 PM10, PM2.5, SO2, NO2, Hg, and CO emissions for coal mined at the 

Caballo Mine that would be used for power generation in comparison with 2013-2017 values. 

Using information from table 4-6, comparisons can be made between combustion emissions 

from coal mined at the Caballo Mine and emissions from coal mined throughout Campbell 

County. Total U.S. emissions are also included in the table.

Table 4-6. Estimated Annual PM10, PM2.5, SO2, NOX, and Hg Contributions from 

Combustion of Coal Mined at the Caballo Mine for 2013-2017 and 2018-

2051, Compared to Campbell County and U.S. Total Emissions

Year Mt Coal 

Recovered

PM10

(Tons)

PM2.5

(Tons)

SO2

Emissions 

(Tons)

NO2

Emissions 

(Tons)

Hg 

Emissions 

(Tons)

CO

Emissions 

(Tons)

2013 9.0 6239.09 1902.9 78567.2 32324.8 0.4 2244.8

2014 8.0 5552.4 1693.5 69921.1 28767.5 0.3 1997.7

2015 11.4 7922.6 2416.4 99768.9 41047. 8 0.5 2850.5

2016 11.2 7797.1 2378.1 98188.6 40397.6 0.5 2805.4

2017 11.1 7730.7 2357.9 97352.1 40053.4 0.5 2781. 5

2018-2051 Annual Average 13.5 9,380.3 2,861.0 118,125.0 48,600.0 0.6 3,375.0

Annual Campbell County1 341.9 237,560.0 72,455.8 2,991.572.9 1,230,818.6 14.2 85,473.5

2018-2051 Average Percent 

of Campbell Co. -- 3.9% 3.9% 3.9% 3.9% 3.9% 3.9%

Total U.S. Coal Emissions 

(2017) 774.6 538,225.7 164,158.8 6,777,831.9 2,788,593.7 32.1 193,652.3

2018-2051 Average Percent 

of U.S. -- 1.7% 1.7% 1.7% 1.7% 1.7% 1.7%

1 Based on an estimated production of 341.9 Mt (average of 2013 through 2017 production). 

Source: WWC 2019, calculations provided in appendix D.

Impacts to air quality related to coal combustion under the Proposed Action would be similar to

the current conditions. When compared to Campbell County emissions, direct and indirect 

effects would be minor (approximately 3.9 percent of the Campbell County average emissions) 

but would be extended by approximately 8.9 years.
Chapter 4 – Environmental Consequences/Cumulative Impacts

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 4-11

The estimated Hg emissions from Caballo Mine supplied coal-fired power plants are provided in 

table 4-6. Based on an average of 13.5 Mtpy, the estimated Hg emissions resulting from the 

Proposed Action would contribute approximately 0.6 tons of Hg emissions per year for an 

additional 8.9 years (WWC 2019).

Impacts to air quality related to coal combustion under the Proposed Action would be similar to 

the conditions currently experienced at the Caballo Mine. When compared to emissions from 

Campbell County mines, direct and indirect effects of the Proposed Action would be minor and 

short-term.

Acidification of Lakes/Acid Deposition

As discussed in section 3.4.1.3.3, the pH trend at monitoring site WY99 appears to be relatively 

stable with values near the pH of normal rain. The Proposed Action is not expected to contribute 

to increased direct or indirect effects to acidification of lakes or acid deposition that may impact 

soils and therefore, the effects would be negligible.

4.4.4.1.2 No Action Alternative

Impacts to air quality related values have resulted from current mining activity, and, therefore,

the impacts related to AQRVs under the No Action Alternative would be similar to those under

the Proposed Action but would not be extended by 8.9 years.

4.4.4.2 Cumulative Effects

Mines in Campbell County would affect the cumulative AQRVs. The air quality index (AQI) for 

Campbell County are used to evaluate the cumulative effects of the Proposed Action on AQRVs. 

As described by the AirNow website, the AQI provides an index of how clean or polluted the 

air is within an area and what associated health effects might be a concern (AirNow 2019). The 

AQI focuses on health affects experienced within a few hours or days after breathing polluted 

air. EPA calculates the AQI for five major air pollutants regulated by the CAA: ground-level ozone, 

particle pollution (also known as particulate matter), CO, SO2, and NO2. Ground-level ozone and 

airborne particles are the two pollutants that pose the greatest threat to human. The AQI 

evaluates air quality based on six levels (categories) of health concern that correspond to a 

different level of health concern (table 4-7). The table shows that approximately 99.3 percent 

of the days in Campbell County between 2013 and 2017 were classified as having a good or 

moderate AQI and no days were classified as very unhealthy or hazardous.

Table 4-7. Average Annual Campbell County Air Quality Index Values

Days 

With 

AQI

Good Moderate

Unhealthy for 

Sensitive 

Groups

Unhealthy Very 

Unhealthy Hazardous

2013 365 222 142 1 0 0 0

2014 365 262 102 1 0 0 0

2015 365 252 110 2 1 0 0

2016 366 262 103 1 0 0 0

2017 365 240 118 4 3 0 0

Average -- 247.6 115.0 1.8 0.8 0 0

Percent of Total 

Average -- 67.8% 31.5% 0.5% 0.2% 0.0% 0.0%

Source: EPA 2019f

Blasting, coal crushing, loading and hauling of coal, moving equipment, and other activities 

associated with surface coal mining and the combustion of coal at power plants produce
Chapter 4 – Environmental Consequences/Cumulative Impacts

4-12 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

particulates that can be released into the air, which could impact AQRVs. The cumulative effects 

on AQRVs are expected to be minor and short-term because estimated emissions would be 

below the NAAQS and WAAQS thresholds and cumulative effects would only be extended by 

approximately 8.9 years.

4.4.4.3 Mitigation Measures

No mitigation measures beyond those required by the Caballo Mine air quality permit would be 

required to protect AQRVs.

4.4.5 Greenhouse Gas Emissions 

4.4.5.1 Direct and Indirect Effects 

4.4.5.1.1 Proposed Action

OSMRE has elected to quantify direct and indirect GHG emissions and has evaluated these

emissions in the context of national GHG emission inventories. Each GHG has a different lifetime 

in the atmosphere and a different ability to trap heat in the atmosphere. To allow different gases 

to be compared and added together, emissions can be converted into CO2e emissions. Annual 

CO2e emissions from combined sources based on annual coal recovered from 2013-2017 at the

Caballo Mine were estimated (section 3.4.1.4). Other than production, the same variables were 

used to calculate annual CO2e emissions for 2018-2051. The CO2e emissions for the Proposed

Action were calculated at 13.5 Mtpy, which is more than the average annual production over the 

last 5 years (10.1 Mtpy).

As presented in table 4-8, the combustion of the coal is the primary contributing factorrelated 

to CO2e emissions from the Proposed Action, accounting for approximately 97 percent of the 

total emissions. Therefore, the direct and indirect effects from GHG emissions when rail 

transport and coal combustion are included are expected to be moderate and short-term.

Table 4.8. Estimated Annual Average 2013-2017 and 2018-2051 Direct and 

Indirect CO2e Emissions at the Caballo Mine

General Estimated 2013-2017 

Annual Average1

Estimated 2018-2051 

Annual Average1

Mt of Coal Recovered 10.1 13.5

Average Transport Miles (One Way) 1,131 1,131

Number of Train Trips (One Way) 655 873

Direct Emissions Sources

Fuel 33,139 44,103

Electricity Consumed in Mining Process 27,085 36,046

Mining Process 11,642 15,494

Total Direct Emissions 71,867 95,643

Indirect Emissions Sources

Rail Transport2 402,475 533,104

From Coal Combustion3 16,991,119 22,612,500

Total Indirect Emissions 17,393,594 23,145,604

Total Estimated CO2e Emissions 17,465,460 23,241,248 1 In metric tons - see appendix C for calculations, 2 Coal haulage emissions based on 130-car trains with four locomotives; 488.2 kg CO2e per mile per loaded train, 96.1 kg CO2e per mile per 

empty train; and one-way mileage to power plants. Coal haulage emissions calculations includes a loaded train and a returning empty train, 

per train trip. 3 Based on 1.683 metric tons CO2e per ton of coal burned for electrical generation (EPA 2008) and calculated by WWC (see appendix C).
Chapter 4 – Environmental Consequences/Cumulative Impacts

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 4-13

Appendix F provides a detailed discussion of the GHG emissions from the U.S. According to 

the EPA (2018) in 2016 (the most recent year of available CO2 data at this time), CO2 emissions 

in the U.S. totaled 6,511.3 million metric tons. Using the 2016 U.S. estimate for comparison 

purposes, the estimated CO2e contribution from the Caballo Mine coal was approximately

0.27 percent. Under the Proposed Action, the estimated CO2e contribution would be 

approximately 0.36 percent of the U.S. total CO2e emissions. The direct and indirect effects of 

the Proposed Action on annual CO2e emissions would be moderate and short-term.

4.4.5.1.2 No Action Alternative

The impacts directly resulting from GHG emissions under the No Action Alternative would be 

less than those under the Proposed Action and would not be extended by approximately

8.9 years.

4.4.5.2 Cumulative Effects

The analyses provided above include direct and indirect effects analysis 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.

4.4.5.3 Mitigation Measures

A majority (approximately 99.7 percent) of the GHG identified in this EA are from non-mining 

activities, not controlled by PCM (e.g., rail transportation to and combustion at power plants). 

The DOI generally has no regulatory authority over GHG emissions from rail transportation and 

coal combustion. Air emissions, both direct and indirect, are regulated by other regulatory 

entities, including WDEQ-AQD (for emissions at the Caballo Mine) and other states’ regulatory 

agencies (for emissions from out-of-state power plants), through permit limits. Given these facts, 

OSMRE has determined that no additional mitigation is required.

4.4.6 Climate Change Cause and Effect

4.4.6.1 Proposed Action/No Action Alternative

Although the effects of GHG emissions and other contributions to climate change in the global 

aggregate are estimable, it is currently not feasible to determine what effect GHG emissions ina 

specific area resulting from a specific activity might have on climate change and resulting 

environmental impacts. It is therefore not currently possible to associate any particular action 

with the creation or mitigation of any specific climate-related environmental effects. Appendix F 

includes a discussion on climate change cause and effect.

As stated in appendix F, estimated CO2 emissions in the U.S. decreased 1.9 percent from2015 

to 2016 (EPA 2018). Under the Proposed Action, PCM anticipates producing the coal included 

in the Caballo West tract at 13.5 Mtpy levels, using existing production and transportation 

facilities. This would extend the mine’s current GHG emissions by approximately 8.9 years and 

combustion of Caballo West tract federal coal in coal-fired power plants would also continue for 

approximately 8.9 additional years. Because CO2 emissions have been declining in recent years 

and because CO2e resulting from coal mined at the Caballo Mine would only be slightly above 

current levels, climate impacts associated with direct/indirect emissions from the Proposed 

Action from mining, transportation, and combustion would be moderate and short-term.
Chapter 4 – Environmental Consequences/Cumulative Impacts

4-14 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

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 EO 12866, which required federal agencies to assess the cost and the benefits of 

intended regulations as part of their regulatory impact analyses. The SCC protocol was also 

developed for use in cost-benefit analyses of proposed regulations that could impact cumulative 

global emissions (Shelanski and Obstfeld 2015). However, EO 13783, issued March 28, 2017, 

directed that the IWG be disbanded and that technical documents issued by the IWG be 

withdrawn as no longer representative of federal policy. The 2017 EO further directed that when 

monetizing the value of changes in GHG emissions resulting from regulations, agencies follow the 

guidance contained in Circular A-4 (Office of Management and Budget 2003). It was determined 

that a federal agency should ensure that its consideration of the information and other factors 

relevant to its decision be consistent with applicable statutory or other authorities, including 

requirements for the use of cost-benefit analysis.

NEPA does not require a cost-benefit analysis (40 CFR § 1502.23) or the presentation of the 

SCC estimates; therefore, that analysis was not undertaken here. Without a complete monetary 

cost-benefit analysis, which would include the social benefits of energy production to society as 

a whole and other potential benefits and costs, inclusion solely of a SCC analysis would be 

unbalanced, potentially inaccurate, and not useful.

Given the uncertainties associated with assigning a specific and accurate social cost of carbon 

estimate resulting from 8.9 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. GHG emission inventories, as discussed in section 4.4.5.

4.4.6.2 Cumulative Effects

The analyses provided above include direct and indirect effects analysis 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.

4.4.6.2.1 Direct and Indirect Cumulative Effects on the Proposed Action/No Action 

Alternative

USGS predicted potential impacts between 2025 and 2049 using the conservative climate change 

scenario (RCP8.5), which assumes no new climate change regulations or reductions would be 

implemented (USGS 2016). According to the USGS National Climate Change Viewer (USGS 

2016), potential climate change impacts in Campbell County could include:

1. annual mean maximum temperature increase of up to 6.5 degrees Fahrenheit,

2. annual mean minimum temperature increase of up to 6.3 degrees Fahrenheit,

3. annual mean precipitation increase of up to 0.1 inch per month,

4. annual mean snowfall decrease of up to 0.1 inch per year,

5. annual mean soil water storage decrease of up to 0.1 inch per year, and

6. annual mean evaporation deficit increase of up to 0.3 inch per month.

For analysis purposes, the EA assumes that the maximum annual mean values would be realized 

during the life of the mine.
Chapter 4 – Environmental Consequences/Cumulative Impacts

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 4-15

Hydrology

The potential changes to the annual snowfall, precipitation levels, and streamflow could impact 

area surface water body levels, groundwater recharge, and soil erosion. Considering the overall 

climate change timeframe of centuries, it is possible that decreased snowpack may be observable 

locally. Likewise, decreases in streamflow may be observed, but, during the mining dewatering 

timeframe of 8.9 years, mine dewatering may compensate for climate change related stream flow 

reduction, or may have no additional influence on streamflow. Overall, the Proposed Action 

would have moderate, short-term impacts to surface water bodies and groundwater; however, 

the impact from changes to these resources based on climate change would be negligible and 

long-term.

Soils

The Proposed Action would involve new surface disturbance of approximately 866.7 acres. As 

described in section 4.8.1.1, the direct and indirect effects related to the Proposed Action to 

soils would be moderate and short-term. The USGS climate viewer does not predict any annual 

mean changes to runoff so impacts from climate changes on soils would be negligible.

Reclamation

The post-reclamation land use would be wildlife habitat and livestock grazing, consisting of 

vegetation cover of grasses and shrubs. Potential changes to the natural environment, as listed 

above, could result in the need to consider different plant species during reclamation to account 

for the higher temperatures and increased precipitation levels. WDEQ-LQD regulates surface 

coal mining operations, including the surface effects on federal lands within the State of Wyoming. 

Federal coal leaseholders in Wyoming are required to submit a PAP to OSMRE and WDEQ-LQD 

for any proposed revisions to reclamation operations on federal lands in the state. Therefore, 

any change to reclamation practices (i.e., seed mix) at the Caballo Mine would require the 

approval of WDEQ-LQD. Climate change impacts on reclamation would be negligible. 

Reestablishment of wildlife and vegetation in areas that have been disturbed is reliant on the 

reclamation process which would be negligibly impacted by climate change; therefore, climate 

change impacts to wildlife and vegetation in reclaimed areas would be negligible and long-term.

4.5 Water Resources

4.5.1 Groundwater

4.5.1.1 Direct and Indirect Effects

4.5.1.1.1 Proposed Action

The direct and indirect effects to groundwater would be the same as those described in section 

3.5.1.2.1.3 of the 2009 SGAC EIS. The general impacts to groundwater as a result of surface coal 

mining include the following:

1. The removal of the coal aquifer and any overburden and alluvial aquifers within 

the areas that are mined and the replacement of these aquifers with backfilled 

overburden material.

2. The lowering of static water levels in the coal and overburden aquifers around the 

mine due to dewatering associated with removal of these aquifers within the mine 

boundaries. The reduction in static water levels would be long-term, but not
Chapter 4 – Environmental Consequences/Cumulative Impacts

4-16 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

permanent, and recharge to the backfill and adjacent undisturbed aquifers would 

occur after mined areas are reclaimed.

3. Other groundwater impacts that may or may not occur, or may occur only at 

specific locations, include changes in water quality (usually deterioration) outside 

the area that is mined and reclaimed. This would result from communication 

between the reclaimed aquifer and the unmined aquifer, and changes in rechargedischarge conditions and/or groundwater flow patterns.

Under the Proposed Action additional alluvium, overburden, and Wyodak coal aquifers would be 

removed in the Caballo West tract during the mining process. These aquifers would be replaced 

with backfilled overburden materials. The physical characteristics of the reclaimed backfill material 

would be dependent upon premining overburden lithology.

Mining at the Caballo Mine has removed Tisdale Creek alluvial deposits. Under the Proposed 

Action, mining would physically remove additional alluvial deposits associated with Tisdale Creek. 

As described in the 2009 SGAC EIS, it is unlikely that WDEQ-LQD would require Caballo Mine 

to selectively remove and replace the alluvial deposits within the Caballo West tract.

Mining in the tract would extend the duration and physical extent of drawdown in the overburden 

within the Caballo Mine. Monitoring well data used in the 2015 CHIA indicate that drawdown in 

the overburden aquifer extends about 2 to 3 miles from the mine pit. The Caballo Mine predicted 

that the extent of the 5-foot water level decline for the overburden would be a maximum of 

about two miles from any mine pit (PCM 2014). West of the mine pit, the overburden 

groundwater gradients follow the general topography.

Under the Proposed Action, the duration and physical extent of drawdown in the Wyodak coal 

aquifer would also be extended. In 2010, drawdown within the Wyodak seam aquifer was 

modeled to determine the extent of drawdown year 2023. The modeling included a portion of 

the Caballo West tract. The extent of drawdown (5-foot contour) in the Wyodak coal aquifer is 

depicted in map 4-1. Groundwater data from the Wyodak coal aquifer would continue to be 

monitored in accordance with the Permit No. 433 groundwater monitoring program and included 

in the annual reports submitted to WDEQ-LQD. Caballo Mine would update the extent of 

drawdown as mining continues.

In the 2015 CHIA, water levels from 41 monitoring wells were used to characterize current 

groundwater levels in the backfill aquifer. The data showed that current conditions are 

representative of the early stages of reclamation of mined areas. In addition, the available data 

show and support that the cumulative effects of mining on groundwater levels are being reduced 

as reclamation progresses and as the backfill aquifer saturates. This is consistent with section 

3.5.1, which indicated that most of the groundwater levels in the backfill wells at the Caballo 

Mine have exhibited significant resaturation.

The underlying, sub-coal Fort Union Formation and the Fox Hills Sandstone would not be 

physically disturbed by mining activities due to the depths. The wells completed in these 

formations for water supply purposes would continue to be used under the Proposed Action. 

Impacts would not increase from current conditions; however, the duration and physical extent 

of drawdown in the Fort Union Formation and the Fox Hills Sandstone would be extended.
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Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 4-17

Map 4-1. Modeled Drawdown for the Wyodak Coal Seam
Chapter 4 – Environmental Consequences/Cumulative Impacts

4-18 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

Overall, the direct and indirect effects to groundwater resources resulting from the Proposed 

Action would be moderate and long-term due to aquifer removal. Impacts would not increase 

from current conditions; however, the duration and physical extent of drawdown in the 

overburden and Wyodak coal aquifer would be extended. Backfill water levels and groundwater 

quality indicate that the groundwater would meet Class III standards for livestock use.

4.5.1.1.2 No Action Alternative

Impacts to groundwater under the No Action Alternative would be similar to those under the 

Proposed Action, but the aerial extent of groundwater aquifer removal would be reduced by 

approximately 866.7 acres. Impacts to overburden and coal aquifers have already occurred within 

the Caballo West tract related to coal recovery on adjacent federal coal leases, ongoing mining 

activities at nearby mines, and CBNG recovery. Under the No Action Alternative, the duration 

of impacts to groundwater would not be extended. Therefore, implementation of the No Action 

Alternative would have negligible effect on reducing the magnitude of these impacts, but would 

reduce the extent and duration.

4.5.1.2 Cumulative Effects

The 5-foot drawdown area was selected as the cumulative impact area (CIA) for groundwater 

because this limit would detect the extent of minor groundwater impacts. This area corresponds

to the CIA used in the 2015 CHIA. The area delineated by the maximum cumulative 5-foot 

drawdown contour in the Wyodak coal aquifer for the central group of mines is included on 

map 4-2. The effects of removal of the coal and overburden aquifers and replacing them with 

backfilled overburden are the foremost groundwater concern regarding cumulative effects. Mining 

the tract would increase the cumulative size of the backfill area in the central group of mines. The 

extent of water level drawdown in the coal and shallower aquifers in the area surrounding the

mines also would be expected to increase slightly as a result of mining the Caballo West tract and

from dewatering the active mine pits. Where the effects of pumping from central group of mines

overlap, additional water level declines would result from concurrent operations.

The 2015 CHIA indicates that few to none of the impacts to the alluvial aquifer are cumulative in 

nature as the individual mines tend to impact different sections of discrete alluvial sediments. In 

addition, the 2015 CHIA states that cumulative impacts caused by mining of the overburden 

aquifer would be minimal. Outside the mined areas, the native overburden aquifer would remain 

structurally undisturbed and would be in hydraulic connection with the backfill aquifer. Basedon 

the current available data, the model predictions by the mines, and the area geology, it is expected 

that the cumulative impacts caused by mining on the native undisturbed overburden aquifer to 

the west of the mine permit boundaries would be negligible.

Mining impacts to groundwater levels in the Wyodak coal aquifer are more extensive than the 

overburden since the coal seams are mined out and the hydraulic conductivity of the coal aquifer 

is higher than the overburden and underburden aquifers. As described in the 2015 CHIA forthe 

central group of mines, CBNG dewatering in the central PRB has been decreasing since 2001. If 

the present trend of CBNG dewatering continues, it is conceivable that the CBNG effects on 

groundwater in the Wyodak coal aquifer would decline over the next several years and the coal 

mining impacts would be more distinguishable. The 2015 CHIA concluded that the impacts on 

groundwater levels and groundwater quality in the Wyodak coal aquifer are expected to be 

minimal and the coal aquifer would be able to support livestock use.
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Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 4-19

Map 4-2. Cumulative Impact Area for Potential Surface Water and Groundwater 

Impacts
Chapter 4 – Environmental Consequences/Cumulative Impacts

4-20 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

The 2015 CHIA included groundwater quality data for 2011 to 2013 from 29 backfill aquifer wells 

from the central group of mines and indicated that from the available data, it is difficult to assess, 

interpret, and predict the groundwater quality of the backfill with a single hypothesis. It is 

generally expected that over time the backfill would be flushed by groundwater flowing through 

the reclaimed material and down gradient to the northwest to the native undisturbed aquifers. 

Thus, the water quality in the backfill is expected to improve over time.

The time to flush backfill and improve the water quality varies considerably based on the 

permeability of the backfill and groundwater flow rates in the aquifers. Based on the predictions 

from the mines and the observed data, it is expected that the backfill aquifer would be a viable 

supply source to support the WDEQ-LQD approved postmining land use of livestock and wildlife. 

This is consistent with section 3.5.1, which indicated that the groundwater quality within the 

backfill wells at the Caballo Mine have water quality that meet Class III standards for livestock 

use, with the exception of one well that is completed in the reclaimed North Tisdale Creek 

alluvium. Outside the central group of mine permit boundaries the backfill aquifer is not present 

and the native existing aquifers would remain structurally undisturbed. The 2015 CHIAindicates 

that it is reasonable to expect that the recovery of the native aquifers outside the permit 

boundaries would be relatively faster than the backfill aquifer, and the existing wells in these 

native aquifers would remain viable to support the existing use.

The 2015 CHIA states that during mining, the underburden aquifer that is in close proximity to 

the mine pits would be impacted in various ways, including some fragmentation, drawdown due 

to the influences of the pit dewatering, and exposure of the aquifer materials for a limited time 

to the atmosphere and direct precipitation events. During the initial stages of backfill aquifer 

resaturation, there is expected to be some upward groundwater flow from the underburden to 

the backfill aquifer. Therefore, in areas where the backfill aquifer would be recharged by the 

underburden aquifer, it is expected to have minimal effects on the underburden aquifer 

groundwater quality. Outside of the mined areas, the aquifersoverlying the underburden aquifer 

would remain structurally undisturbed. In addition, the relatively lower hydraulic conductivity of 

the underburden aquifer supports that coal mining would have limited cumulative effects on the 

underburden groundwater system and these effects would be declining with increasing distance 

from the coal mine permit boundaries to the west.

As discussed in section 4.5.1.1.1, while the physical characteristics of the backfill is different 

from premining conditions, backfillrecharge has been documented at the Caballo Mine. In addition, 

backfill water quality is generally suitable for livestock use and wildlife habitat, which are the 

planned postmining land uses. Therefore, cumulative effects to groundwater resources resulting 

from the Proposed Action are expected to be moderate and long-term.

4.5.1.3 Mitigation Measures

W.S. 35-11-415(b)(xii) requires surface coal mines to replace any domestic, agricultural, 

industrial, or any other legitimate use groundwater supplies if, as a result of mining, a supply is 

diminished, interrupted, or contaminated, to the extent of precluding use of the water. The 

WDEQ-LQD requires surface coal mine permittees to enhance or restore the hydrologic 

conditions of disturbed land surfaces and minimize adverse impacts to the hydrologic balance. 

The recharge capacity of the reclaimed lands would be restored to a condition which minimizes 

disturbance to prevailing hydrologic balance in the permit area and in adjacent areas (WDEQLQD 2012).
Chapter 4 – Environmental Consequences/Cumulative Impacts

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 4-21

Under provisions of Permit No. 433, Caballo Mine is required to monitor water levels and water 

quality in the alluvium, overburden, coal, underburden, and backfill (PCM 2014). Operational 

groundwater monitoring programs are dynamic and modified through time as wells are removed 

by mining, discontinued from monitoring to eliminate redundancy, or added to replace those 

removed by mining and to facilitate monitoring of future mine expansion areas as mining has 

progressed. Additional wells have also been installed in the reclaimed backfill to monitor 

recovering, postmining groundwater conditions. Many groundwater monitoring wells installed by 

Caballo Mine within and around its current permit area have been used to evaluate groundwater 

conditions associated with the mine and continue to be monitored to reveal a long-term record 

of groundwater conditions. After the completion of reclamation, a large groundwater monitoring 

network would remain. This would include not only backfill wells, but also a number of coal, 

overburden, and alluvial wells in undisturbed areas.

4.5.2 Surface Water

4.5.2.1 Direct and Indirect Effects

4.5.2.1.1 Proposed Action

Additional discussions regarding surface water impacts can be found in section 3.5.2.2 of the 2009 

SGAC EIS. Additional discussions can also be found in the Surface Water portion of the 2015 

CHIA. As discussed in section 3.5.2, there are currently no surface water monitoring stations

on Tisdale Creek and baseline water quality indicated few exceedances of WDEQ-WQD Class 3B 

water quality standards.

Under the Proposed Action changes in surface runoff characteristics and sediment discharges 

would occur because of the mining and reconstruction of drainage channels as mining progresses 

and because of the use of sediment control structures used to manage discharges of surface water 

from the mine permit areas. Since the tract would be mined as an extension of the existing 

Caballo Mine there would not be a significant increase in the size of the area that is disturbed at 

any given time. Reclamation would be ongoing and concurrent with mining. Stream channels 

would be restored after surface mining operations are completed on the tract. Under the 

Proposed Action, the postmining drainage area of Tisdale Creek would increase by 2.4 square 

miles (12 percent) due to the opening of the closed basins within the watershed and a slight 

encroachment into the premining North Tisdale watershed. The North Tisdale postmining 

drainage area would decrease by about 1.4 square miles (20 percent). The impacts associated 

with the changes in postmining drainage areas would be small because watershed modeling

indicates that postmining runoff would be similar to premining conditions. In Coal Rules and 

Regulations, Chapter 1, Section 2(cd), WDEQ-LQD defines material damage to the hydrologic 

balance as a significant long-term or permanent adverse change to the hydrologic regime 

(WDEQ-LQD 2014b). WDEQ-LQD Coal Rules and Regulations require surface coal mine 

permittees to enhance or restore the hydrologic conditions of disturbed land surfaces and 

minimize adverse impacts to the hydrologic balance (WDEQ-LQD 2012). Because the results of 

modeling indicate that postmining flood estimates would be similar to premining, the direct and 

indirect effects to surface water are expected to be moderate until final bond release has been

obtained.

4.5.2.1.2 No Action Alternative

The impacts to surface water under the No Action Alternative would be similar to those under 

the Proposed Action since impacts to surface water features have already occurred within the 

tract related to coal recovery on adjacent federal coal leases, as approved by Permit No. 433.
Chapter 4 – Environmental Consequences/Cumulative Impacts

4-22 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

Therefore, implementation of the No Action Alternative would have negligible effect on reducing 

the magnitude of surface water impacts.

4.5.2.2 Cumulative Effects

The surface water CIA includes the entire Caballo Creek drainage area upstream from USGS 

Station No. 06425900 (map 4-2). The CIA is the area where existing and proposed mining 

activities may cause measurable changes to the hydrologic environment and depends on the 

characteristics of the surface systems. The 2015 CHIA analyzed the cumulative mining related 

impacts to surface water resources associated within the Caballo Creek and concluded that 

considering the size of CIA, the chances of measuring water quantity changes that would be 

persistent and detectable at USGS Station No. 06425900 are small. The 2015 CHIA also 

acknowledges CBM surface water discharge into Caballo Creek; however, because CBM

production in the Caballo Creek drainage has been declining since 2001, cumulative effects to 

surface water from CBM would be negligible. Therefore, the cumulative effects to surface water 

are expected to be minor.

4.5.2.3 Mitigation Measures

Permit No. 433 requires PCM to restore stream channels after surface mining operations are 

completed. The major drainages of the Caballo Mine would be reclaimed using a channel-valley 

floor system consisting of an inner pilot channel designed to accommodate a 2-year recurrence 

interval flood and an outer flood channel designed to serve as a guide for major floods and prevent 

floodwaters from spreading outside the floodplain area (PCM 2014). An additional aspect of 

reclamation would involve the establishment of a pool and riffle system within the channel 

bottom. The restored guide channel within a floodplain channel with the incorporation of the 

pool and riffle system would be functionally and morphologically analogous to the existing channel 

and floodplain systems. Minor tributaries to the major drainages would be constructed by 

contouring the reclaimed topography into swales rather than constructed channels. These minor 

tributaries would aid in controlling potential erosion by channelizing overland flow.

Surface runoff would be controlled by a series of detention berms, diversion ditches, and 

sedimentation ponds. All necessary hydrologic control facilities would be constructed according 

to applicable state and federal requirements. All mining related surface water discharges are 

permitted under a Wyoming Pollutant Discharge Elimination System (WYPDES) program under 

Permit No. WY0025755, which requires treatment, monitoring, and reporting of all surface 

discharges. A number of postmining impoundments would be constructed to replace premining 

features and to provide opportunities for stock and wildlife watering.

4.5.3 Water Rights

4.5.3.1 Direct and Indirect Effects

4.5.3.1.1 Proposed Action

Impacts to water rights would be the same as those described in section 3.5.3.2.1.3 of the 2009 

SGAC EIS. Prior to energy development in the area, water appropriations (both groundwater 

and surface water) were typically for livestock use. However, mining companies currently hold 

the majority of the water rights.

As stated in section 3.5.2.1.3 of the 2009 SGAC EIS, some privately permitted water wells in the 

vicinity of the Caballo West tract have been or would likely be impacted (either by removing the 

well or by water level drawdown) by mining and CBNG development. Future drawdowns to the
Chapter 4 – Environmental Consequences/Cumulative Impacts

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 4-23

Wyodak coal aquifer are expected to be negligible because the coal seam has essentially been 

dewatered. Therefore, it is unlikely that any of these privately permitted water wells would be 

impacted by water level drawdown to a greater extent than they currently are under the 

Proposed Action although the duration of impacts would be extended.

Only attenuation of normal peak flows downstream of the Caballo Mine is expected under the 

Proposed Action, since runoff is currently being controlled as a result of mining unrelated to the 

tract. Therefore, it is unlikely that any of the privately permitted surface water rights would be 

impacted by removal of surface water features within the tract.

In general, the proposed federal mining plan modification would contribute to additional, more 

extensive, mining disturbance that may impact groundwater and surface water rights in the 

Caballo Mine permit area. Impacts to groundwater and surface water rights have already occurred

from mining within the Caballo Mine and from CBNG development and implementation of the 

Proposed Action would have negligible effect on increasing the extent of impacts. Therefore, the 

Proposed Action would not result in substantial declines in the groundwater or surface water 

availability for livestock use and wildlife habitat. Under the Proposed Action impacts to 

groundwater and surface water rights would be minor and long-term.

4.5.3.1.2 No Action Alternative

The impacts to surface and groundwater rights under the No Action Alternative would be similar 

to those under the Proposed Action because impacts to groundwater and surface water have 

already occurred within the tract related to coal recovery on adjacent federal coal leases. 

Therefore, implementation of the No Action Alternative would have a minor effect on water 

rights.

4.5.3.2 Cumulative Effects

The CIA for water rights impacts are the same as those described above for groundwater and 

surface water. The type and number of groundwater and surface water rights within 2 miles of 

the tract are discussed in section 3.5.3. While the approval of the federal mining plan 

modification would contribute to additional, more extensive mining disturbance in the central

group of mines, there would be minor additional cumulative water rights impacts because 

groundwater systems have already been affected by CBNG removal and ongoing mining and 

because runoff is currently being controlled by the mines.

The 2015 CHIA concluded that the limited amount of disturbance relative to the size of the 

Caballo Creek CIA makes it unlikely that water quality changes would be detectable at the point 

of accumulation at USGS Station No. 06425900. Because dilution from water outside the permit 

areas helps negate impacts to water quality, the potential for the mines to cumulatively impact 

surface water quality in the Caballo Creek CIA is likely low and no material damage to surface 

water quality is expected. Any impacts to downstream water rights would fall under the 

jurisdiction of the SEO.

The 2015 CHIA concluded that although coal mining will have impacts, the impacts would not 

cause irretrievable loss of the groundwater resource to support existing or reasonably 

foreseeable uses outside of the coal mine permit boundaries. In addition, as discussed in section 

4.5.1.3, W.S. 35-11-415(b)(xii) requires that mines replace, in accordance with state law, the 

water supply of an owner of interest in real property, who obtains all or part of his supply of

water for domestic, agricultural, industrial, or any other legitimate use from an
Chapter 4 – Environmental Consequences/Cumulative Impacts

4-24 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

underground or surface source where the supply has been affected by contamination, diminution, 

or interruption resulting from the surface coal mine operation.

4.5.3.3 Mitigation Measures

Permit No. 433 requires PCM to cooperate with water right holders on site specific mitigation 

plans for all existing water rights affected by mining (PCM 2014). A typical mitigation plan would 

include documenting that drawdown has occurred, lowering the pump so that more water is 

available, and if necessary, installing a pump with a larger lift capacity. If further mitigation is 

needed or if the wells are disturbed by mining, Caballo would drill a new well into the Fort Union 

Formation below the coal seam, and a solar pump or windmill would be installed. The

replacement plan would be finalized in consultation with the water right owner prior to drilling 

the replacement wells.

4.6 Alluvial Valley Floors

4.6.1 Direct and Indirect Effects

4.6.1.1 Proposed Action

The direct and indirect effects to AVFs would not be different from those described in section 

3.6.2.1 of the 2009 SGAC EIS. Because the only AVFs on Tisdale Creek are located approximately 

4 miles downstream of the Caballo West tract, there would be no direct and indirect effects to

AVFs.

4.6.1.2 No Action Alternative

Impacts to the AVFs have resulted from current mining activity; therefore, implementation of the 

No Action Alternative would have a minor effect on AVFs.

4.6.2 Cumulative Effects

The cumulative effects to AVFs would not be significantly different than those described in section 

4.2.6 of the 2009 SGAC EIS. Areas outside of the permitted mines have generally not been

surveyed for the presence of AVFs; therefore, the locations and extent of the AVFs outside of the

mine permit areas have not been determined. The cumulative effects on AVFs are expected to be

negligible.

4.6.3 Mitigation Measures

No mitigation measures would be necessary for AVFs.

4.7 Wetlands/Aquatic Features

4.7.1 Direct and Indirect Effects

4.7.1.1 Proposed Action

The direct and indirect effects to wetlands would not be different from those described in section 

3.7.2.1 of the 2009 SGAC EIS. Follow-up wetlands delineations and USACE determinations have

shown that there are no jurisdictional wetlands and only 1.79 acres of aquatic features within and

adjacent to the Caballo West tract. The Proposed Action would result in the loss of approximately 

1.19 acres of aquatic features since approximately 0.60 acre have already been disturbed related

to disturbance resulting from approved coal recovery from adjacent lands. Disturbed nonjurisdictional aquatic features would be replaced during the reclamation phase of
Chapter 4 – Environmental Consequences/Cumulative Impacts

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 4-25

mining. The direct and indirect effects to aquatic features are expected to be minor and shortterm.

4.7.1.2 No Action Alternative

Under the No Action Alternative impacts to non-jurisdictional aquatic features would be the 

same as the Proposed Action, but reduced by 1.19 acres.

4.7.2 Cumulative Effects:

Disturbed jurisdictional and non-jurisdictional features would be restored as required by the 

authorized federal, state, or private surface landowner, as specified in the mining permits, which 

are approved by WDEQ-LQD before mining operations would be conducted. Therefore, there 

would be no net loss of jurisdictional and non-jurisdictional features and cumulative impacts 

would be negligible.

4.7.3 Mitigation Measures

Disturbed non-jurisdictional aquatic features would be restored as required by the authorized 

federal, state, or private surface landowner, as specified in the mining permit, which are approved 

by WDEQ-LQD before mining operations commence.

4.8 Soil

4.8.1 Direct and Indirect Effects

4.8.1.1 Proposed Action

The direct and indirect effects to soils would not be different from those described in section

3.8.2.1 of the 2009 SGAC EIS. Soils within the Caballo West tract would be altered under the 

Proposed Action. Following reclamation, the replaced topsoil should support a stable and 

productive native vegetation community adequate in quantity and quality to support planned 

postmining land uses (i.e., rangeland and wildlife habitat). The direct and indirect effects related 

to the Proposed Action to soils would be moderate (866.7 acres of disturbance) and short-term.

4.8.1.2 No Action Alternative

The impacts to soils under the No Action Alternative would be similar to those under the 

Proposed Action although the impacts to approximately 866.7 acres would not occur.

4.8.2 Cumulative Effects

The cumulative impacts to soils would not be significantly different than those described in section 

4.2.7 of the 2009 SGAC EIS. According to the 2015 CHIA, over the mid 2012 to early 2014 

period, the life-of-mine disturbed acreage at the central group of mines totaled approximately 

32,294 acres. Of this total, approximately 28 percent was actively mined, 28 percent was 

in long-term mining or reclamation facilities, and 44 percent had been backfilled and graded. Areas 

within active mines are progressively disturbed and would progressively be reclaimed by planting

appropriate vegetation species to restore soil productivity and prevent soil erosion. The 

cumulative effects related to soils would be moderate and short-term.

4.8.3 Mitigation Measures

Suitable soil would be salvaged and stockpiled to support plant growth for use in reclamation. 

Sediment control structures would be built to trap eroded soil and revegetation would reduce 

wind erosion. PCM would replace all salvaged topsoil in a manner which ensures successful
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4-26 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

revegetation and supports the postmining land uses. Regraded overburden would be sampled to 

verify suitability as subsoil for compliance with root zone criteria as specified by WDEQ-LQD 

Guideline No. 1A (Topsoil and Subsoil) (WDEQ LQD 2015c). Unsuitable materials would be 

removed and either treated, reblended or replaced with the required depth of suitable 

overburden material or the affected area would be capped such that a minimum of the required 

depth of suitable material exists.

4.9 Vegetation

4.9.1 Direct and Indirect Effects

4.9.1.1 Proposed Action

The direct and indirect effects to vegetation would not be different from those described in 

section 3.9.2.1 of the 2009 SGAC EIS. Direct effects associated with the removal of vegetation 

from the Caballo West tract would include increased soil erosion and habitat loss for wildlife and 

livestock over what is currently being experienced. Indirect effects on reclaimed lands would 

include loss of habitat or loss of habitat carrying capacity for some wildlife species as a result of 

reduced plant species diversity or plant density, particularly big sagebrush. However, livestock 

and grassland-dependent wildlife species would benefit from the increased grass cover and 

production. As discussed in section 3.9.1, the Ute ladies’-tresses, which is listed as threatened, is 

the only plant T&E wildlife species with the potential of occurring in the area. This species was 

not located within the tract during surveys conducted in 2007, 2009, and 2010 and there are no 

critical habitats for this T&E species within the Caballo West tract.

Reclamation, including revegetation, would occur contemporaneously with mining on adjacent 

lands (i.e., reclamation would begin after an area is mined). In an effort to approximate premining 

conditions, PCM would plan to reestablish vegetation types during the reclamation operation that 

are similar to the premining types. Reestablished vegetation would be dominated by species 

mandated in the reclamation seed mixtures (to be approved by WDEQ-LQD). The reclamation 

plan for PCM includes steps to control invasion by weedy (invasive, nonnative) plant species. The 

direct and indirect effects related to the Proposed Action on vegetation would be moderate and 

short-term.

4.9.1.2 No Action Alternative

The impacts to vegetation under the No Action Alternative would be similar to those underthe 

Proposed Action although the impacts to approximately 866.7 acres to recover federal coal 

would not occur.

4.9.2 Cumulative Effects

Cumulative effects would be similar to those described in section 4.8.3. The overall contribution 

to cumulative effects to vegetation would be minor due to the localized effects and the improved 

productivity on mined lands that have been reclaimed.

4.9.3 Mitigation Measures

Revegetation success would be evaluated until the final reclamation bond is released.

4.10 Wildlife

The direct and indirect effects to wildlife would not be different from those described in section

3.10.1.2 of the 2009 SGAC EIS. Impacts to wildlife that would result from mining the
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Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 4-27

Caballo West tract have been addressed by the WGFD and WDEQ-LQD when Permit No. 433 

was amended to include the tract.

The environmental consequences related to mining the tract for big game, other mammals, upland 

game birds (excluding the GRSG), other birds, amphibians, reptiles, and aquatic species are not 

significantly different than those presented in 2009 SGAC EIS and are not presented herein. 

Updated discussions for raptors, GRSG, T&E species, and SOSI are included below.

4.10.1 Raptors

4.10.1.1 Direct and Indirect Effects

4.10.1.1.1 Proposed Action

Intact raptor nests are located within the tract. However, based on the low number of nesting 

raptors within the tract and the PCM’s approved plans and procedures in place to reduce impacts 

to raptors, the direct and indirect effects related to the Proposed Action on site-specific raptors 

would be moderate and short-term.

4.10.1.1.2 No Action Alternative

Under this alternative, disturbance related impacts to raptors in the area would continue, but the 

duration of impacts would be reduced by approximately 8.9 years.

4.10.1.2 Cumulative Impacts

The cumulative effects related to the Proposed Action on regional raptor populations would be 

moderate and short-term.

4.10.1.3 Mitigation Measures

No mitigation measures specific to raptors are necessary. PCM’s general reclamation practices 

for establishing or enhancing post‐mine wildlife habitat are described in the Reclamation Plan of 

Permit No. 433. PCM also has developed plans and procedures to minimize impacts to nesting 

raptors and ensure proper reclamation techniques are implemented to enhance habitat in the 

postmining landscape for raptors and their primary prey species.

4.10.2 Greater Sage-grouse (GRSG) 

4.10.2.1 Direct and Indirect Effects 

4.10.2.1.1 Proposed Action

As discussed in section 3.10.2, long-term results from annual lek monitoring suggest that the 

Caballo Mine permit area only supports GRSG when regional populations are especially high. 

Only one of the six historical leks with within the Caballo West tract 4-mile radius of concern 

has an occupied WGFD management status and this lek has not been active since 2009. The 

closest GRSG core area to the tract is the Thunder Basin core area, which is approximately

8.8 miles distant, and there are no winter concentration or connectivity areas near the tract. 

Ongoing operations may adversely impact individual GRSG but are not likely to result in a loss of 

population viability in the wildlife monitoring area or cause a trend toward federal listing. Potential 

impacts to GRSG would likely be limited primarily to indirect influences resulting from habitat 

disturbance, though loss of individual birds may occur at times. The use of appropriate timing and 

spatial buffers, timely implementation of reclamation, and application of targeted conservation 

measures in suitable habitats both on- and off-property throughout the region are expected to 

sufficiently reduce overall impacts to maintain a viable population within the area.
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4-28 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

The direct and indirect effects related to the Proposed Action on GRSG would be minor and 

short-term.

4.10.2.1.2 No Action Alternative

Under this alternative, disturbance related impacts to GRSG in the area would continue, butthe 

duration of impacts would be reduced by approximately 8.9 years.

4.10.2.2 Cumulative Impacts

WGFD information for the central group of mines indicate that the average number of male 

grouse per lek (3.7) was down 45 percent in 2018 compared to 2017 (WGFD 2018). However, 

the average number of males per lek observed in 2018 was equal to the 10-year annual average 

(3.7) and the 3-year running average rate of change (linear trendline), based on 2009 through 

2018 CIA lek average annual counts, increased over the time period. The cumulative effects on 

regional GRSG populations related to disturbance at the central group of mines would be 

moderate and short-term.

4.10.2.3 Mitigation Measures

No mitigation measures specific to GRSG are necessary. PCM’s general reclamation practices for 

establishing or enhancing post‐mine wildlife habitat are described in the Reclamation Plan of 

Permit No. 433. Shrub seedlings would be planted in shrub pockets to improve the beneficial 

effects of the shrubs for wildlife.

4.10.3 Threatened, Endangered, and Candidate Species and Species of Special 

Interest

4.10.3.1 Direct and Indirect Effects

4.10.3.1.1 Proposed Action

As discussed in section 3.10.3.1, the northern long-eared bat, which is listed as threatened, is 

the only vertebrate T&E wildlife species with the potential of occurring in the area. There are no 

critical habitats for this T&E species within the Caballo West tract or within Campbell County. 

According to the USFWS, the primary threat to the northern long-eared bat is WNS. The 

northern long-eared bat is also threatened by the loss and degradation of summer habitat, by 

collision with or barotrauma (injury to the lungs due to a change in air pressure) caused by wind 

turbines, and mine closures and vandalism of winter roosts and hibernacula. No wind turbines 

are within the general area and, as described in section 3.10.3.1, preferred roosting and 

reproductive habitats are limited in the Caballo Mine permit area and surrounding 1.0-mile 

monitoring area. However, potential foraging areas are present throughout the Caballo Mine 

permit area and surrounding monitoring area. No northern long-eared bat populations have been 

documented within the Caballo Mine survey area (permit area and 1.0-mile perimeter) (PCM 

2018b).

Because the Caballo West tract lies within the AOI for the northern long-eared bat and the WNS 

zone, OSMRE has an obligation to consult with USFWS. OSMRE has complied with the 

programmatic biological opinion (BO) and fulfilled the Section 7 consultation requirements under 

the Endangered Species Act through submission of the Northern Long-eared Bat 4(d) rule 

streamlined consultation form to the Wyoming Ecological Field Services Office. On March 29, 

2019 OSMRE received a memorandum from USFWS indicating that although the Proposed 

Action may affect the northern long-eared bat, there are no effects beyond those previously
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Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 4-29

disclosed in the USFWS’s programmatic biological opinion for the final 4(d) rule (USFWS 2019b). 

Therefore, the programmatic biological opinion satisfies OSRMRE’s responsibilities under section 

7 of the ESA relative to the northern long-eared bat.

A discussion of SOSI that could potentially occur in the area is included in section 3.10.3.2 and 

a list of these species is included in appendix E. This impacts assessment related to the Proposed 

Action focus on WGFD SGCN and the WGFD tier ranking. Of the 50 SOSI that could occur in 

the tract, 46 are SGCN, of which 24 have been observed in the area. Two of the WGFDSGCN 

(burrowing owl and mountain plover) are classified as Tier I species and both of these species 

have been observed in the area. The burrowing owl has been documented as nesting in the area, 

while the mountain plover has been recorded only rarely.

If present, these T&E species and SOSI would be temporarily displaced but current mining and 

reclamation practices in place at the Caballo Mine would protect species and promote the return 

of these species once reclamation has been completed. In an effort to approximate premining 

conditions, PCM would reestablish vegetation types during the reclamation operation that are 

similar to the premining types. The direct and indirect effects related to the Proposed Action on 

T&E species and SOSI would be moderate and short-term.

4.10.3.1.2 No Action Alternative

Under this alternative, disturbance related impacts to T&E species and SOSI would continue, but 

the duration of impacts would be reduced by approximately 8.9 years.

4.10.3.2 Cumulative Impacts

The cumulative effects on regional T&E species and other species of special interest populations 

would be related to disturbance at the central group of mines and would be moderate and shortterm.

4.10.3.3 Mitigation Measures

No mitigation measures specific to T&E species and SOSI are necessary. The general reclamation 

practices for establishing or enhancing postmining wildlife habitat at the Caballo Mine described 

in the Reclamation Plan of Permit No. 433 are in place. Shrub seedlings would be planted in shrub 

pockets to improve the beneficial effects of the shrubs for SOSI.

4.11 Land Use and Recreation

4.11.1 Direct and Indirect Effects

4.11.1.1 Proposed Action

The direct and indirect effects to land use and recreation would not be different from those 

described in Section 3.11.2.1 of the 2009 SGAC EIS. Surface ownership within the CaballoWest 

tract is private (PCM) and proposed coal removal is managed by the BLM. The primary land use 

impacts of the Proposed Action would be reduction of livestock grazing, loss of wildlife habitat, 

and curtailment of other mineral development. Livestock grazing has already been prohibited due 

to the tract being inside the permit boundary and adjacent to active mine areas. Hunting on the 

tract is currently not allowed because it is within the mine permit boundary and wouldcontinue 

to be disallowed during mining and reclamation. While non-coal mineral development would be 

curtailed on the tract, much of the CBNG has been depleted in the shallower production areas. 

Following reclamation, the land would be suitable for grazing and wildlife uses, which are the
Chapter 4 – Environmental Consequences/Cumulative Impacts

4-30 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

historic land uses. Therefore, the direct and indirect effects related to land use would be negligible 

and short-term.

4.11.1.2 No Action Alternative

Under the No Action Alternative, disturbance related impacts would be the same as the 

Proposed Action, but disturbance would be reduced by approximately 866.7 acres.

4.11.2 Cumulative Impacts

Cumulative effects would be similar to those described in section 4.8.3. The overall contribution 

to cumulative effects to vegetation would be minor due to the localized effects and the improved 

productivity on mined lands that have been reclaimed.

Cumulative effects would be related to land use at the central group of mines. As described in 

section 4.8.3, disturbed acreage at the central group of mines totaled approximately 32,294

acres. Because the mines own or control the surface within their permit boundaries, the loss of 

agricultural land would not directly impact other landowners in the area. There is alsolimited 

recreational use of the area. Following reclamation, the land would be suitable for historical uses 

of grazing and wildlife uses and recreational use. As stated above, much of the CBNG within the 

shallower production areas of the PRB has been depleted. Therefore, cumulative impacts from 

the Proposed Action on land use would be negligible.

4.11.3 Mitigation Measures

No mitigation measures specific to land use and recreation are necessary.

4.12 Cultural Resources

4.12.1 Direct and Indirect Effects

4.12.1.1 Proposed Action

The direct and indirect effects to cultural resources would not be different from those described 

in section 3.12.2.1 of the 2009 SGAC EIS. The Caballo West tract has been subjected to Class III 

cultural resource inventories and none of the sites identified have been classified as NRHP eligible 

sites that would require mitigation prior to disturbance. The direct and indirect effects on cultural 

resource from the Proposed Action would be negligible but long-term.

Letters of consultation were sent out to 24 Native American tribes/tribalrepresentatives during 

the scoping process. OSMRE received a response from the Comanche Nation indicating that the 

location of the Caballo West tract has been cross referenced with Comanche Nation site files 

and no properties were identified. OSMRE also received a response from the Cheyenne and 

Arapaho tribes indicating that Caballo West tract area has been categorized as No Adverse Effect.

4.12.1.2 No Action Alternative

Under the No Action Alternative, disturbance related impacts would be the same as the 

Proposed Action, but disturbance would be reduced by approximately 866.7 acres.

4.12.2 Cumulative Impacts

The individual evaluation of cultural resource sites in the central group of mines suggests that 

through avoidance of sensitive site types and mitigation through data recovery for all unavoidable 

disturbance to NRHP eligible sites, the cumulative effects to cultural resources have been minimal. 

The cumulative impacts on cultural resource would be negligible but long-term.
Chapter 4 – Environmental Consequences/Cumulative Impacts

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 4-31

4.12.3 Mitigation Measures

No mitigation measures specific to cultural resources are necessary.

4.13 Visual Resources

4.13.1 Direct and Indirect Effects

4.13.1.1 Proposed Action

The direct and indirect effects to land use and recreation would not be different from those 

described in section 3.13.2.1 of the 2009 SGAC EIS. Potential direct effects would arise from 

disturbance associated with the Proposed Action and would cease upon reclamation. Potential 

indirect effects consist of permanent changes to existing topography and the vegetative 

component of the area, irrespective of reclamation success. Mining activities would be visible 

from State Highway 59 and the Bishop Road, though the extent and duration of visibility would 

vary according to the visual perspective from the roads. The nearest occupied residence is 

approximately 3,200 feet from the tract boundary. The direct and indirect effects related to visual 

resources could affect local residences and are therefore listed as moderate and long-term.

4.13.1.2 No Action Alternative

Under the No Action Alternative, visual resource related impacts would be the same as the 

Proposed Action, but disturbance would be reduced by approximately 866.7 acres.

4.13.2 Cumulative Impacts

Cumulative visual resources effects would be related to disturbance at central group of mines 

and from oil and gas development. Human disturbances include, but are not limited to, agriculture, 

mining, roads, urban areas, and oil and gas development. Given the fact that moderate visual 

impacts are currently occurring in the area and that the effects from the Proposed Action are 

not significantly greater than current effects, the cumulative effects related to the visual resources 

would be moderate and long-term.

4.13.3 Mitigation Measures

Current BACT measures would continue to be employed at the Caballo Mine to control visibility 

impacts from particulates, which could affect visibility.

4.14 Noise

4.14.1 Direct and Indirect Effects

4.14.1.1 Proposed Action

The direct and indirect effects to noise would be the same as those described in section 3.14.2.1 

of the 2009 SGAC EIS. Under the Proposed Action, noise levels would not increase but would 

be extended by 8.9 years. Potential blasting related noise impacts would be 53 dBA at the closest 

residence (approximately 3,200 feet to the west). Because of the remoteness of the Caballo West 

tract and because mining is already on going in the area, noise would have few off-site impacts. 

Wildlife in the immediate vicinity of the tract may be adversely affected by the noise during mining 

operations; however, anecdotal observations at surface coal mines in the area suggest thatsome 

wildlife may adapt to increased noise associated with coal mining activity. Although noise levels 

would not significantly change as a result of the Proposed Action, the direct and indirect effects
Chapter 4 – Environmental Consequences/Cumulative Impacts

4-32 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

related to the Proposed Action could affect local residences for a longer period of time and are 

therefore listed as moderate and long-term.

4.14.1.2 No Action Alternative

Under the No Action Alternative, noise impacts would be the same as the Proposed Action, but 

the extent of the impacts would be reduced by approximately 8.9 years.

4.14.2 Cumulative Effects

Cumulative effects would be related to disturbance at central group of mines. Potential sources 

of noise disturbances include, but are not limited to, agriculture, mining, roads, urban areas, and 

oil and gas development. Potential impacts would cease upon project completion and successful 

reclamation in a given area. Recreational users, local residents, and grazing lessees using lands 

surrounding active mining areas do hear mining-related noise, but this has not been reported to 

cause a substantial impact. The cumulative impacts related to noise as discerned by the public 

would be moderate but short-term.

4.14.3 Mitigation Measures

No mitigation measures specific to noise impacts are necessary.

4.15 Transportation Facilities

4.15.1 Direct and Indirect Effects

4.15.1.1 Proposed Action

The direct and indirect effects to transportation facilities would be the same as those described 

in section 3.15.2.1 of the 2009 SGAC EIS. Under the Proposed Action Bishop Road would be 

relocated, but other existing transportation facilities, including roads, railroads, coal conveyors, 

and overhead electrical transmission lines associated with the Caballo Mine would continue to 

be used. Relocation of Bishop Road would only result in minor impacts to existing traffic patterns, 

which has a low utilization and impacts would be short-term. The Proposed Action would not 

result in increased mine related traffic but would extend impacts by 8.9 years.

All of the coal mined at the Caballo Mine would continue to be transported by rail. Based on an 

estimated annual production rate of 13.5 Mt of coal shipped by rail and an estimated 15,470 tons 

of coal per train, the Proposed Action would result in approximately 873 train trips per year (one 

way). The variation in coal destinations and multiple rail transportation routes make it speculative 

to analyze the potential impacts to the entire rail corridor in detail. Under the ProposedAction, 

the number of trains shipping coal from Caballo Mine would not change, but the duration would 

be extended by 8.9 years.

Coal dust and fines blowing or sifting from moving, loaded rail cars has been linked to railroad 

track stability problems resulting in train derailments and to rangeland fires caused by 

spontaneous combustion of accumulated coal dust (BLM 2009). While no specific studies of coal 

dust impacts have been conducted in the PRB, BNSF has been involved in research regarding the 

impacts of coal dust escaping from loaded coal cars on rail lines in the PRB. BNSF has determined 

that coal dust poses a serious threat to the stability of the track structure and the operational 

integrity of rail lines in, and close to, the mines in the PRB. In response to suits brought on by 

environmental groups alleging that coal spilled from trains pollutes waterways, BNSF Railway has 

agreed to study the use of physical covers for coal trains to reduce the effects of blowing coal 

particles (Seattle Times 2016). BNSF has cited studies and experience to demonstrated that
Chapter 4 – Environmental Consequences/Cumulative Impacts

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 4-33

shippers can take steps in the loading of coal cars using existing, cost-effective technology that 

will substantially reduce coal dusting events. BNSF has a Coal Loading Rule, in effect since 

October 2011, specifically requiring all shippers loading coal at any Montana or Wyoming mine 

to take measures to load cars in such a way that ensures coal dust losses in transit are reduced 

by at least 85% compared to cars where no remedial measures have been taken (BNSF 2016).

Two recent Australian studies involved measuring particle concentrations in the air near a coal 

haul transport corridor to assess whether coal dust was being emitted from the railcars and 

whether any such emissions would result in particulate matter concentrations that would be 

considered potentially harmful to human health. The two reports presented strong evidence that, 

while particulate levels were elevated for the several minutes during and after trains passed the 

monitoring station, coal trains did not result in any more emissions than any other freight-hauling 

trains (Ramboll Environ 2016).

Overall, the added direct and indirect effects of the Proposed Action on transportation would 

be minor and short-term.

4.15.1.2 No Action Alternative

Under the No Action Alternative, transportation impacts in the area would be the same as the 

Proposed Action, but the duration of the impacts would be reduced by approximately 8.9 years.

4.15.2 Cumulative Impacts

Cumulative impacts to transportation are related to coal production levels. If coal production 

levels increase, cumulative impacts to transportation would increase. Highway traffic accidents 

and delays at grade crossings could result from train traffic. The transportation facilities for the 

central group of mines are already in place, and coal production and employment levels would 

not change.

Coal extracted from the existing surface coal mines in the Wyoming PRB is transported in rail 

cars along the BNSF and Union Pacific (UP) rail lines. The coal mines south of Gillette, including 

the Caballo Mine, ship most of their coal via the Gillette to Douglas BNSF and UP joint trackage 

that runs south through Campbell and Converse counties and then east over separate BNSF and 

UP mainlines for destinations in the Midwest. The Proposed Action would extend the duration 

of mining by approximately 8.9 years at the Caballo Mine, and thus the duration of utilization of 

BNSF and UP rail lines would be extended by that amount.

The cumulative impacts related to transportation would be minor and short-term.

4.15.3 Mitigation Measures

No mitigation measures specific to transportation facilities are necessary.

4.16 Hazardous and SolidWaste

4.16.1 Direct and Indirect Effects

4.16.1.1 Proposed Action

The direct and indirect effects to hazardous and solid waste would not be different from those 

described in section 3.16.2.1 of the 2009 SGAC EIS. Under the Proposed Action hazardous and 

solid waste would not increase but generation would be extended by 8.9 years. Direct and 

indirect effects on hazardous and solid wastes would be minor and short-term.
Chapter 4 – Environmental Consequences/Cumulative Impacts

4-34 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

4.16.1.2 No Action Alternative

Under the No Action Alternative, hazardous and solid wastes would continue to be generated 

at the Caballo Mine, but the duration of the impacts would be reduced by approximately

8.9 years.

4.16.2 Cumulative Impacts

Cumulative hazardous and solid wastes effects would be related to mining operations at the 

central group of mines. Potential impacts would cease upon project completion and successful 

reclamation in a given area. The cumulative impacts related to hazardous and solid waste as would 

be minor and short-term.

4.16.3 Mitigation Measures

No mitigation measures specific to hazardous and solid wastes are necessary.

4.17 Socioeconomics

4.17.1 Direct and Indirect Effects

4.17.1.1 Proposed Action

Wyoming, Campbell County, Campbell County School District 1, the City of Gillette, and many 

other governmental entities across the state receive revenues derived directly and indirectly from 

taxes and royalties on the production of federal coal, including that at the Caballo Mine. Such 

revenues include lease bonus bids, ad valorem taxes, severance taxes, royalty payments, sales and 

use taxes on equipment and other taxable purchases, and portions of required contributions to 

the federal AML program and Black Lung Disability Trust Fund. A summary of federal and state 

revenues generated from recovery of federal coal from the Caballo Mine and Caballo West tract 

are provided in table 4-9 and table 4-10, respectively.

Table 4-9. LOM Federal and State Revenues from Federal Coal Recovery within 

the Caballo Mine (millions of dollars)

Revenue Source Total $ Collected Federal Revenue State Revenue

Federal Mineral Royalties 693.6 346.8 346.8

Abandoned Mine Lands Fund 124.3 62.1 62.1

Severance Tax 286.0 --1 286.0

Bonus Bid Annual Revenues2 0.0 0.0 0.0

Ad Valorem Tax 234.1 --1 234.1

Black Lung 18.7 18.7 --1

Sales and Use Tax 35.6 --1 35.6

Totals 1,392.3 427.6 964.7 1 No revenues disbursed. 2 No bonus bid revenues collected after 2016. 3 Total does not equal subtotals due to rounding. 

Source: WWC calculation – provided in appendix D
Chapter 4 – Environmental Consequences/Cumulative Impacts

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 4-35

Table 4-10. LOM Federal and State Revenues from Federal Coal Recovery within 

the Caballo West Tract (millions of dollars)

Revenue Source Total $ Collected Fed Revenue State Revenue

Federal Mineral Royalties 187.2 93.6 93.6

Abandoned Mine Lands Fund 33.5 16.8 16.8

Severance Tax 74.2 --1 74.2

Bonus Bid Annual Revenues2 0.0 0.0 0.0

Ad Valorem Tax 63.2 --1 63.2

Black Lung 5.0 5.0 --1

Sales and Use Tax 9.6 --1 9.6

Totals 372.7 115.4 257.4 1 No revenues disbursed. 2 No bonus bid revenues collected after 2016. 

Source: WWC calculation – provided in appendix D

Under the Proposed Action, Wyoming revenues generated from LOM Caballo Mine production 

could be increased by approximately $257.4 million and federal revenues could be increased by

$115.4 million. The primary difference between state and federal revenues is related to the fact 

that severance, ad valorem, and sales and use taxes are only paid to the state of Wyoming. The 

Proposed Action would extend the duration of the economic impacts related to mining the 

federal coal.

Mining in the tract would not directly create new jobs and therefore, the availability of housing 

units would not be impacted. No additional employees are anticipated as a result of the Proposed 

Action, although the duration of employment for current employees would be extended.

No additional changes in the current socioeconomic situation are anticipated. Direct and indirect 

effects on socioeconomics under the Proposed Action would be moderate and short-term.

4.17.1.2 No Action Alternative

Under the No Action Alternative, approximately $257.4 million of Wyoming revenues and 

approximately $115.4 million of federal revenues would not be realized. The selection of the No 

Action Alternative would likely not result in direct job losses, but any revenue, state program 

funding, abandoned mine land fees, and black lung fees that might otherwise be generated by 

extending the LOM by 8.9 years would not be collected. In addition, the duration of employment 

for current employees would be reduced by 8.9 years. The No Action Alternative would result 

in moderate direct and indirect socioeconomic effects.

4.17.2 Cumulative Impacts

Cumulative effects would be related to socioeconomic conditions in Campbell County. 

Cumulative effects are not substantially different than those described in section 4.17.1.1 

because Wyoming, Campbell County, Campbell County School District 1, the City of Gillette, 

and many other governmental entities across the state receive revenues derived directly and 

indirectly from taxes and royalties on the production of federal coal from Campbell County. The 

cumulative effects on socioeconomics are expected to be moderate and short-term.

4.17.3 Mitigation Measures

No mitigation measures specific to reducing socioeconomic impacts are necessary.
Chapter 4 – Environmental Consequences/Cumulative Impacts

4-36 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

4.18 Short-Term Uses and Long-Term Productivity

This section relates to the balance or trade-off between short-term uses and long-term 

productivity for each resource in relation to the Proposed Action. The discussions contained 

throughout this environmental consequences chapter, in the existing Caballo Mine federal mining 

plan, and in the 2009 SGAC EIS provide adequate analyses and relationships of short-term uses 

(such as mining coal) and long-term productivity (such as generating electricity for homes, schools, 

and industry).

4.19 Unavoidable Adverse Effects

Unavoidable adverse impacts are the effects on natural and human resources that would remain 

after mitigation measures have been applied. These impacts range from negligible to moderate and 

short to long-term. For the Proposed Action, details regarding these impacts are presented in the 

preceding resource sections and the 2009 SGAC EIS. Unavoidable adverse effects are summarized 

in table 4-11.
Chapter 4 – Environmental Consequences/Cumulative Impacts

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 4-37

Table 4-11. Unavoidable Adverse Effects of the Proposed Action

Resource Unavoidable Adverse Effect

Topography and 

Physiography

Topographic effects of mining are unavoidable because mining activities such as 

blasting, excavating, loading and hauling of overburden and coal are required to 

recover coal in an economical manner.

Geology, Mineral 

Resources and 

Paleontology

Geology, mineral resources, and buried paleontological resources may be permanently 

impacted by mining activities. Such impacts are unavoidable as the resources cannot be 

avoided during mining.

Air Quality/GHGs Emissions and associated impacts are unavoidable but are not expected to degrade 

ambient air quality in the area. Mined coal is primarily used for combustion; therefore, 

any associated GHG emissions are unavoidable if the Proposed Action is implemented.

Water Resources Impacts to water resources resulting from coal extraction are unavoidable. However, 

these impacts would be mitigated through replacement of groundwater or surface

water supplies for domestic, agricultural, industrial, or any other legitimate use if such 

a supply is diminished, interrupted, or contaminated to the extent of precluding use of 

the water as a result of mining.

Soils Soil in disturbance areas would exhibit more homogenous textures and may have 

coarser fragments near the surface following mining. Some soil loss may occur as a 

result of erosion, prior to stabilization. Microbial and chemical impacts due to 

accelerated erosion and mixing of soil zones may occur as a result of disturbance.

Vegetation Vegetation would be eliminated beginning with the initial disturbance and continuing 

until reclamation is complete. Noxious weeds may be introduced as a result of mining 

activity, potentially affecting vegetation communities and requiring implementation of 

control measures in the long term.

Wildlife Wildlife would be temporarily affected by mine activities, which would alter habitat 

conditions, particularly in the vicinity of surface disturbance. These impacts would be 

short term and habitats would be reclaimed following mining.

Cultural Resources No sites within the Caballo West tract have been designated as eligible for listing on 

the NRHP. Undiscovered cultural resources could be impacted by surface disturbing 

activities. Any newly-discovered NRHP-eligible sites would be mitigated as required by 

Section 106 of the NHPA.

Visual Resources Mining activity and associated disturbances and facilities would unavoidably alter the 

landscape during the mining term, affecting the aesthetic qualities. Some features 

would be visible from public access points, including state Highway 59.

Noise Noise would result from mining activities similar to the existing condition.

Transportation 

Facilities

State Highway 59 would continue to experience mine related traffic. Bishop Road may 

be relocated.

Hazardous and Solid 

Waste

Coal mining and associated coal processing would yield coal waste.

Chapter 5 – Consultation and Coordination

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 5-1

5.0 Consultation and Coordination

5.1 Public Comment Process

OSMRE developed a project specific website that provided legal notices, outreach notice letters, 

mailing address, and an email address for comments to be sent. The website is available at: 

https://www.wrcc.osmre.gov/initiatives/caballoMine.shtm.

OSMRE released a public NOI to prepare the Caballo Mine Caballo West tract EA in the Gillette 

News Record on December 19, 2018 and again on February 8, 2019. Public outreach letters 

describing the EA and soliciting comments were mailed on December 19, 2018 and again on 

February 5, 2019 to a total of 172 recipients, including city governments, adjacent landowners, 

and other interested parties and 26 tribes/tribal representatives (see Appendix A). The legal 

notices and letters invited the public to comment on issues of concern related to the EA. Written 

comments were solicited until February 22, 2019. Appendix B presents a summary of the 

scoping comments received by the public. Seven comment letters were received during the public 

scoping period. Comment letters received during the public review period for this EA would be 

considered during the ASLM approval process.

5.2 Preparers and Contributors

OSMRE personnel that contributed to the development of this EA are listed in table 5-1. 

Table 5-1. OSMRE Personnel

Name Organization Project Responsibility

Elizabeth Shaeffer OSMRE Project Lead

Logan Sholar OSMRE Project Coordination

Gretchen Pinkham OSMRE Air Quality/Transportation

Roberta Martínez-Hernández OSMRE Hydrology

Jeremy Iliff OSMRE Cultural/Historical/Paleontological

Third party contractors who contributed to the development of this EA are identified in

table 5-2.

Table 5-2. Third Party Contractor Personnel

Name Organization Project 

Responsibility

Education

Beth Kelly WWC Engineering Primary Author B.S. Chemical Engineering

John Berry WWC Engineering Author, QAQC B.S. Wildlife Management

Jack Fritz WWC Engineering QAQC B.S. Chemical Engineering

Mal McGill WWC Engineering AutoCAD A.S. Engineering

5.3 Distribution of the EA

This EA will be distributed to individuals who specifically request a copy of the document. It will 

also be made available electronically on the OSMRE website at 

https://www.wrcc.osmre.gov/initiatives/caballoMine.shtm.

Chapter 6 – References

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 6-1

6.0 References

AirNow, 2019, Air Quality Index (AQI) Basics. Available on the internet as of January 2019: 

https://airnow.gov/.

Barney, R., 2019, Personal communication between Reo Barney, WDEQ-AQD, and Beth Kelly, 

WWC Engineering, February 15, 2019.

Bureau of Land Management (BLM), 2008, BLM Manual 6840 – Special Status Species 

Management. Available on the internet as of December 2018: 

https://www.blm.gov/sites/blm.gov/files/uploads/mediacenter_blmpolicymanual6840.pdf.

Bureau of Land Management (BLM), 2009, Environmental Impact Statement for the South 

Gillette Area Coal Lease Applications WYW172585, WYW173360, WYW172657, 

WYW161248. Available on the internet as of December 2018: 

https://eplanning.blm.gov/epl-frontoffice/eplanning/legacyProjectSite.do?methodName=renderLegacyProjectSite&projectId=

67025.

Bureau of Land Management (BLM), 2010, Record of Decision for the Caballo West Lease by 

Application, Campbell County, Wyoming WYW172657. Available on the internet as of 

December 2018:

https://eplanning.blm.gov/epl-frontoffice/eplanning/legacyProjectSite.do?methodName=renderLegacyProjectSite&projectId=

67025.

Bureau of Land Management (BLM), 2011, Caballo West LBA Coal Data Sheet. Available on the 

internet as of December 2018: https://eplanning.blm.gov/epl-frontoffice/projects/nepa/67025/101140/123162/Caballo_West_LBA.pdf.

Bureau of Land Management (BLM), 2015, Buffalo Field Office Approved Resource Management 

Plan, September 2015. Available on the internet as of December 2018: 

https://eplanning.blm.gov/epl-frontoffice/eplanning/planAndProjectSite.do?methodName=dispatchToPatternPage¤tPa

geId=48300.

BNSF Railway (BNSF), 2016, BNSF Railway Statement on STB Coal Dust Decision, Coal Dust 

Frequently Asked Questions. Available on the internet as of April 2019: 

http://www.bnsf.com/ship-with-bnsf/energy/coal/coal-dust.html.

Commission for Environmental Cooperation (CEC), 2011, North American Power Plant Air 

Emissions. Available on the internet as of December 2018: 

http://www3.cec.org/islandora/en/item/10236-north-american-power-plant-airemissions-en.pdf.
Chapter 6 – References

6-2 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

Department of Interior (DOI), 2004, Department of the Interior Departmental Manual Part

516. Available on the internet as of December 2018: 

http://www.blm.gov/wo/st/en/prog/planning/nepa/webguide/departmental_manual.html.

Hydro-Engineering, LLC. (Hydro-Engineering), 2016, Gillette Area Groundwater Monitoring 

Organization (GAGMO) 35-year Report. Electronic copy only, available on request from 

OSMRE.

IML Air Science, 2013, Caballo Mine Ambient Air Monitoring Network, 4th Quarter & Annual 

Report 2013. Electronic copy only, available on request from OSMRE.

IML Air Science, 2014, Caballo Mine Ambient Air Monitoring Network, 4th Quarter & Annual 

Report 2014. Electronic copy only, available on request from OSMRE.

IML Air Science, 2015, Caballo Mine Ambient Air Monitoring Network, 4th Quarter & Annual 

Report 2015. Electronic copy only, available on request from OSMRE.

IML Air Science, 2016, Caballo Mine Ambient Air Monitoring Network, 4th Quarter & Annual 

Report 2016. Electronic copy only, available on request from OSMRE.

IML Air Science, 2017, Caballo Mine Ambient Air Monitoring Network, 4th Quarter & Annual 

Report 2017. Electronic copy only, available on request from OSMRE.

Interagency Monitoring of Protected Environments (IMPROVE), 2019, Data Acquired from 

Interagency Monitoring of Protected Visual Environments. Available on the internet as of 

January 2019: http://vista.cira.colostate.edu/improve/.

McVehil-Monnett Associates, Inc. (McVehil-Monnett), 2014, Air Quality Permit Application to 

Modify the Belle Ayr Mine. MMA Project Number 2578-13. Prepared for Alpha Coal 

West. Electronic copy only, available on request from OSMRE.

National Atmospheric Deposition Program (NADP), 2014, National Atmospheric Deposition 

Program 2013 Annual Summary. NADP Data Report 2014-01. Illinois State Water 

Survey, University of Illinois at Urbana-Champaign, IL. Available on the internet as of 

January 2019: http://nadp.slh.wisc.edu/lib/dataReports.aspx.

National Atmospheric Deposition Program (NADP), 2015, National Atmospheric Deposition 

Program 2014 Annual Summary. NADP Data Report 2015-01. Illinois State Water 

Survey, University of Illinois at Urbana-Champaign, IL. Available on the internet as of 

January 2019: http://nadp.slh.wisc.edu/lib/dataReports.aspx.

National Atmospheric Deposition Program (NADP), 2016, National Atmospheric Deposition 

Program 2015 Annual Summary. NADP Data Report 2016-02. Illinois State Water 

Survey, University of Illinois at Urbana-Champaign, IL. Available on the internet as of 

January 2019: http://nadp.slh.wisc.edu/lib/dataReports.aspx.
Chapter 6 – References

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 6-3

National Atmospheric Deposition Program (NADP), 2017, National Atmospheric Deposition 

Program 2016 Annual Summary. NADP Data Report 2017-01. Illinois State Water 

Survey, University of Illinois at Urbana-Champaign, IL. Available on the internet as of 

January 2019: http://nadp.slh.wisc.edu/lib/dataReports.aspx.

National Atmospheric Deposition Program (NADP), 2018, National Atmospheric Deposition 

Program 2017 Annual Summary. Wisconsin State Laboratory of Hygiene, University of 

Wisconsin-Madison, WI. Available on the internet as of January 2019: 

http://nadp.slh.wisc.edu/lib/dataReports.aspx.

Natural Resource Conservation Service (NRCS), 2008, Letter to Jamie Eberly Regarding Prime 

Farmland within the Caballo West Tract. Electronic copy only, available on request from 

OSMRE.

Natural Resource and Energy Explorer (NREX), 2018, Mapping Tool for Wyoming. Available on 

the internet as of December 2018: https://nrex.wyo.gov/.

Natural Resources Revenue Data, 2019, Federal Production by Location. Available on the 

internet as of January 2019: https://revenuedata.doi.gov/downloads/federal-production/.

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2018: http://psc.state.wy.us/pscdocs/dwnload/SageGrouseExecOrder2015-7.pdf.

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on request from OSMRE.

Office of Surface Mining Reclamation and Enforcement (OSMRE), 2012, Letter from Dale 

Herbert (OSMRE) to Mary Hopkins (Wyoming SHPO) RE: Cultural Resource Review of 

Caballo Mine’s Southwest Amendment Area Peabody Powder River Operations, LLC. 

Electronic copy only, available on request from OSMRE.
Chapter 6 – References

6-4 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

Office of Surface Mining Reclamation and Enforcement (OSMRE), 2017, Annual Evaluation 

Report for the Regulatory Program Administered by the Department of Environmental 

Quality – Land Quality Division of Wyoming, for Evaluation Year 2017. Available on the 

internet as of January 2019: https://www.odocs.osmre.gov/.

Office of Surface Mining Reclamation and Enforcement (OSMRE), 2019a, Initiatives – Caballo 

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https://www.wrcc.osmre.gov/initiatives.shtm.

Office of Surface Mining Reclamation and Enforcement (OSMRE), 2019b, Reclamation 

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Peabody Caballo Mining, LLC (PCM), 2017, 2017 Caballo Mine Emission Inventory. Electronic 

copy only, available on request from OSMRE.

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Caballo Mine, and Beth Kelly, WWC Engineering, November 30, 2018. Electronic copy 

only, available on request from OSMRE.

Peabody Caballo Mining, LLC (PCM), 2018b, Caballo Mine Permit No. 433-T7, 2018 Annual 

Report, June 21, 2018. Electronic copy only, available on request from OSMRE.

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copy only, available on request from OSMRE.

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request from OSMRE.

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request from OSMRE.

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Cordero Rojo Mine Wyoming Air Quality Permit #MD-9943 Technical Support 

Document. Electronic copy only, available on request from OSMRE.
Chapter 6 – References

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 6-5

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U.S. Army Corps of Engineers (USACE), 2010, Letter to Philip Murphree Regarding the 

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Electronic copy only, available on request from OSMRE.

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Authorization to Continue Operations within the Caballo Mine Permit Boundary. 

Electronic copy only, available on request from OSMRE.

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Report. Available on the internet as of January 2019: https://www.epa.gov/outdoor-airquality-data/monitor-values-report.
Chapter 6 – References

6-6 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

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Northern Long-Eared Bat Myotis septentrionalis. Available on the internet as of January 

2019: https://www.fws.gov/midwest/endangered/mammals/nleb/nlebFactSheet.html.

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Species, Northern Long-eared Bat. Available on the internet as of February 2018: 

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U.S. Fish and Wildlife Service (USFWS), 2018b, List of Threatened and Endangered Species that 

may occur in your Proposed Project Location, and/or may be Affected by your 

Proposed Project. Electronic copy only, available on request from OSMRE.

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Available on the internet as of January 2019: 

https://www.fws.gov/midwest/endangered/mammals/nleb/4drule.html.

U.S. Fish and Wildlife Service (USFWS), 2019b, Memorandum RE: Northern long-eared bat 

consultation for Caballo Mine West Tract Environmental Assessment. Electronic copy 

only, available on request from OSMRE.

U.S. Geological Survey (USGS), 2016, National Climate Change Viewer. Available on the 

internet as of January 2019: https://www2.usgs.gov/climate_landuse/clu_rd/nccv.asp.
Chapter 6 – References

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 6-7

Wyoming Department of Environmental Quality - Air Quality Division (WDEQ-AQD), 2006, 

Air Quality Permit MD-1477. Electronic copy only, available on request from OSMRE.

Wyoming Department of Environmental Quality - Air Quality Division (WDEQ-AQD), 2014, 

Permit Waiver for Air Quality Permit MD-1477. Electronic copy only, available on 

request from OSMRE.

Wyoming Department of Environmental Quality - Land Quality Division (WDEQ-LQD), 2012, 

Chapter 4 Environmental Protection Performance Standards for Surface Coal Mining 

Operations. Available on the internet as of January 2019: 

https://rules.wyo.gov/Search.aspx?mode=1.

Wyoming Department of Environmental Quality - Land Quality Division (WDEQ-LQD), 2013, 

Email from Craig Hults, WDEQ-LQD to Marilee O’Rourke (OSMRE) RE: Caballo Mine 

Southwest Amendment Cultural Inventory. Electronic copy only, available on request 

from OSMRE.

Wyoming Department of Environmental Quality - Land Quality Division (WDEQ-LQD), 2014a, 

Guideline No. 20 Bond Release Categories and Submittal Procedures for Coal Mines.

Available on the internet as of January 2019: 

http://deq.wyoming.gov/lqd/resources/guidelines/.

Wyoming Department of Environmental Quality - Land Quality Division (WDEQ-LQD), 2014b, 

Chapter 1 Authorities and Definitions for Surface Coal Mining Operations. Available on 

the internet as of January 2019: https://rules.wyo.gov/Search.aspx?mode=1.

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Approval of Peabody Caballo Mining, LLC, Caballo Coal Mine Southwest Amendment 

(Permit No. 433-T7; TFN 5 2/363) Change No. 6 Amendment No. 1. Electronic copy 

only, available on request from OSMRE.

Wyoming Department of Environmental Quality - Land Quality Division (WDEQ-LQD), 2015b, 

Cumulative Hydrologic Impact Assessment of Coal Mining in the Central Powder River 

Basin, November 2015, WDEQ-CHIA-37. Electronic copy only, available on request 

from OSMRE.

Wyoming Department of Environmental Quality - Land Quality Division (WDEQ-LQD), 2015c, 

Guideline No. 1A Topsoil and Subsoil. Available on the internet as of January 2019: 

http://deq.wyoming.gov/lqd/resources/guidelines/.

Wyoming Department of Workforce Services (WDWS), 2008, Annual Report of the State 

Inspector of Mines of Wyoming. Available on the internet as of January 2019: 

http://www.wyomingworkforce.org/businesses/mines/info/.
Chapter 6 – References

6-8 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

Wyoming Department of Workforce Services (WDWS), 2011, Annual Report of the State 

Inspector of Mines of Wyoming. Available on the internet as of January 2019: 

http://www.wyomingworkforce.org/businesses/mines/info/.

Wyoming Department of Workforce Services (WDWS), 2012, Annual Report of the State 

Inspector of Mines of Wyoming. Available on the internet as of January 2019: 

http://www.wyomingworkforce.org/businesses/mines/info/.

Wyoming Department of Workforce Services (WDWS), 2013, Annual Report of the State 

Inspector of Mines of Wyoming. Available on the internet as of January 2019: 

http://www.wyomingworkforce.org/businesses/mines/info/.

Wyoming Department of Workforce Services (WDWS), 2014, Annual Report of the State 

Inspector of Mines of Wyoming. Available on the internet as of January 2019: 

http://www.wyomingworkforce.org/businesses/mines/info/.

Wyoming Department of Workforce Services (WDWS), 2015, Annual Report of the State 

Inspector of Mines of Wyoming. Available on the internet as of January 2019: 

http://www.wyomingworkforce.org/businesses/mines/info/.

Wyoming Department of Workforce Services (WDWS), 2016, Annual Report of the State 

Inspector of Mines of Wyoming. Available on the internet as of January 2019: 

http://www.wyomingworkforce.org/businesses/mines/info/.

Wyoming Department of Workforce Services (WDWS), 2017, Annual Report of the State 

Inspector of Mines of Wyoming. Available on the internet as of January 2019: 

http://www.wyomingworkforce.org/businesses/mines/info/.

Wyoming Department of Workforce Services (WDWS), 2018, Wyoming Labor Force Trends 

May 2018, Vol. 55 No. 5. Available on the internet as of December 2018: 

http://doe.state.wy.us/lmi/backiss.htm.

Wyoming Game and Fish Department (WGFD), 2018, Wyoming Game and Fish Department 

Unpublished Data – 2009-2017 Annual Lek Monitoring. Electronic copy only, available 

on request from OSMRE.

Wyoming Game and Fish Department (WGFD), 2019, Wyoming Species of Greatest 

Conservation Need. Available on the internet as of January 2019: 

https://wgfd.wyo.gov/WGFD/media/content/PDF/Habitat/SWAP/SGCN-Introduction.pdf.

Wyoming Oil and Gas Conservation Commission (WOGCC), 2018, Download. Available on 

the internet as of July 2018: http://pipeline.wyo.gov/legacywogcce.cfm.

Wyoming Oil and Gas Conservation Commission (WOGCC), 2019, Well Search. Available on 

the internet as of January 2019: http://pipeline.wyo.gov/legacywogcce.cfm.
Chapter 6 – References

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 6-9

Wyoming State Engineer’s Office (SEO), 2019, e-Permit Application and Water Rights 

Database. Available on the internet as of January 2019: 

https://sites.google.com/a/wyo.gov/seo/.

Wyoming State Historic Preservation Office (SHPO), 2012, Letter from Joseph Daniel (SHPO) 

to Dale Herbort (OSMRE) RE: Cultural Resource Review of 16 sites on Caballo Mine, 

PT433 Peabody Powder Operations, LLC. Electronic copy only, available on request 

from OSMRE.

Wyoming State Historic Preservation Office (SHPO), 2019, Resource Definitions and 

Recording Guidelines. Available on the internet as of January 2019: 

http://wyoshpo.state.wy.us/index.php/programs/review-and-consultation-s106/guidelinesstandards-and-legislation.

WWC Engineering (WWC), 2019, GHG, Air Quality, and Socioeconomic Calculations located 

in Appendices C and D, respectively.

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

APPENDIX A

LEGAL NOTICES

FOR FEDERAL LEASE MODIFICATION APPROVAL 

WYW172657

Appendix A

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 A-1

Public Notice

Caballo Mining Plan Modification 

Environmental Assessment

The U.S. Department of the Interior (DOI), Office of Surface Mining Reclamation and 

Enforcement (OSMRE), Western Region Office, will prepare an environmental assessment (EA) 

for the implementation of a federal mining plan for the Caballo Mine West Tract for federal coal 

lease WYW172657 (the Project). In accordance with the Mineral Leasing Act of 1920 (MLA), the 

DOI Assistant Secretary for Land and Minerals Management (ASLM) must approve the Project 

before any mining and reclamation can occur on lands containing leased federal coal. The lease 

and sale of the federal coal included in the Caballo West LBA (WYW172657) was originally 

evaluated in the 2009 South Gillette Area Coal Lease Applications Environmental Impact 

Statement (2009 SGAC EIS). The coal was offered for sale in a sealed-bid, competitive lease 

process on August 17, 2011. Following determination by BLM that the highest bid at the sale met 

or exceeded the fair market value of the coal within the tract, the bid submitted by Alpha 

Wyoming Land Company was accepted. The lease was subsequently transferred from Alpha 

Wyoming Land Company to BTU Western Resources on July 24, 2012. BTU Western Resources 

owns and operates the Caballo Mine. The coal would be mined using conventional surface-mining 

methods and shipped from an onsite railroad loading facility to various sites within the United 

States. On November 30, 2015, the Wyoming Department of Environmental Quality 

(WDEQ)/Land Quality Division (LQD) approved Caballo Coal Company’s (CCC) application to 

amend the Mine Permit No. 433 to include 1,294 acres, which included the Caballo West Tract.

OSMRE is preparing this EA to evaluate the environmental impacts resulting from the Project, 

pursuant to the requirements of the National Environmental Policy Act of 1969 (NEPA). The 

Caballo Mine is located in Campbell County, Wyoming, approximately 10 miles south-southeast 

of Gillette. The Project is located on federal coal leases administered by the Bureau of Land 

Management (BLM) Casper Field Office and located within the Caballo Mine’s permit area, 

approved in accordance with the Surface Mining Control and Reclamation Act. The amount of 

remaining recoverable federal coal authorized for recovery within currently approved federal 

mining plans is approximately 363.9 million tons (Mt). The Project proposes to add approximately

119.8 Mt of recoverable federal coal. The annual production rate used to calculate the 

environmental impacts resulting from the Proposed Action will be 13.5 million tons per year 

(Mtpy), which is the estimated future annual production rate suggested by CCC and is below the 

maximum permitted production rate of 35 Mtpy set by WDEQ/AQD air quality permit MD1477. CCC started operation in 1979 and the mine will continue to operate until 2042 under the 

current, approved mining plan. Using the estimated 13.5 Mtpy production rate, the Project would 

extend the life of the mine by approximately 8.9 years, to 2051.

The EA will update, clarify, and provide new and additional environmental information for the 

Project that has become available since the 2009 SGAC EIS was approved and the lease was 

issued. As a result of the EA process, OSMRE will determine whether or not there are significant 

environmental impacts. An environmental impact statement will be prepared if the EA identifies 

significant impacts. If a finding of no significant impact is reached, and pursuant to 30 CFR 746.13, 

OSMRE will prepare and submit to the ASLM a mining plan decision document recommending 

approval, disapproval, or conditional approval of the mining plan. As required under the Mineral 

Leasing Act of 1920, the ASLM will approve, disapprove, or conditionally approve the mining plan 

approval document within the mining plan decision document.
Appendix A

A-2 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

ATTN: Caballo West Tract EA 

C/O: Logan Sholar,

OSMRE Western Region 

1999 Broadway, Suite 3320

Denver, CO 80202-3050

Comments may also be emailed to: osm-nepa-wy@osmre.gov, ensure the subject line reads: 

ATTN: OSMRE, Caballo West Tract EA. Comments should be received or postmarked no later 

than January 19, 2019 to be considered during the preparation of the EA. Comments received, 

including names and addresses of those who comment, will be considered part of the public 

record for this project and will be available for public inspection. Additional information regarding 

the Project may be obtained from Logan Sholar, telephone number (303) 293-5036 and the 

Project website provided below. When available, the EA and other supporting documentation 

will be posted at:

http://www.wrcc.osmre.gov/initiatives/caballoMine.shtm.
Appendix A

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 A-3

The OSMRE Western Region website was inaccessible from late December, 2018 through 

January, 2019 due to the government shutdown. Therefore, OSMRE is extending the scoping 

period for the preparation of an Environmental Assessment (EA) for the Caballo Mine West 

Tract new Federal mining plan for an additional 15 days. Scoping comments will be accepted from 

February 7, 2019 to February 22, 2019.

The U.S. Department of the Interior (DOI), Office of Surface Mining Reclamation and 

Enforcement (OSMRE), Western Region Office, will prepare an environmental assessment (EA) 

for the implementation of a federal mining plan for the Caballo Mine West Tract for federal coal 

lease WYW172657 (the Project). In accordance with the Mineral Leasing Act of 1920 (MLA), the 

DOI Assistant Secretary for Land and Minerals Management (ASLM) must approve the Project 

before any mining and reclamation can occur on lands containing leased federal coal. The lease 

and sale of the federal coal included in the Caballo West LBA (WYW172657) was originally 

evaluated in the 2009 South Gillette Area Coal Lease Applications Environmental Impact 

Statement (2009 SGAC EIS). The coal was offered for sale in a sealed-bid, competitive lease 

process on August 17, 2011. Following determination by BLM that the highest bid at the sale met 

or exceeded the fair market value of the coal within the tract, the bid submitted by Alpha 

Wyoming Land Company was accepted. The lease was subsequently transferred from Alpha 

Wyoming Land Company to BTU Western Resources on July 24, 2012. BTU Western Resources 

owns and operates the Caballo Mine. The coal would be mined using conventional surface-mining 

methods and shipped from an onsite railroad loading facility to various sites within the United 

States. On November 30, 2015, the Wyoming Department of Environmental Quality 

(WDEQ)/Land Quality Division (LQD) approved Caballo Coal Company’s (CCC) application to 

amend the Mine Permit No. 433 to include 1,294 acres, which included the Caballo West Tract.

OSMRE is preparing this EA to evaluate the environmental impacts resulting from the Project, 

pursuant to the requirements of the National Environmental Policy Act of 1969 (NEPA). The 

Caballo Mine is located in Campbell County, Wyoming, approximately 10 miles south-southeast 

of Gillette. The Project is located on federal coal leases administered by the Bureau of Land 

Management (BLM) Casper Field Office and located within the Caballo Mine’s permit area, 

approved in accordance with the Surface Mining Control and Reclamation Act. The amount of 

remaining recoverable federal coal authorized for recovery within currently approved federal 

mining plans is approximately 363.9 million tons (Mt). The Project proposes to add approximately

119.8 Mt of recoverable federal coal. The annual production rate used to calculate the 

environmental impacts resulting from the Proposed Action will be 13.5 million tons per year 

(Mtpy), which is the estimated future annual production rate suggested by CCC and is below the 

maximum permitted production rate of 35 Mtpy set by WDEQ/AQD air quality permit MD1477. CCC started operation in 1979 and the mine will continue to operate until 2042 under the 

current, approved mining plan. Using the estimated 13.5 Mtpy production rate, the Project would 

extend the life of the mine by approximately 8.9 years, to 2051.

The EA will update, clarify, and provide new and additional environmental information for the 

Project that has become available since the 2009 SGAC EIS was approved and the lease was 

issued. As a result of the EA process, OSMRE will determine whether or not there are significant 

environmental impacts. An environmental impact statement will be prepared if the EA identifies 

significant impacts. If a finding of no significant impact is reached, and pursuant to 30 CFR 746.13, 

OSMRE will prepare and submit to the ASLM a mining plan decision document recommending 

approval, disapproval, or conditional approval of the mining plan. As required under the Mineral 

Leasing Act of 1920, the ASLM will approve, disapprove, or conditionally approve the mining plan 

approval document within the mining plan decision document.
Appendix A

A-4 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

OSMRE is soliciting public comments on the Project. Your comments will help to determine the 

issues and alternatives that will be evaluated in the environmental analysis. You are invited to 

direct these comments to:

ATTN: Caballo West Tract EA 

C/O: Logan Sholar

OSMRE Western Region 

1999 Broadway, Suite 3320,

Denver, CO 80202-3050

Comments may also be emailed to: osm-nepa-wy@osmre.gov, ensure the subject line reads: 

ATTN: OSMRE, Caballo West Tract EA. Comments should be received or postmarked no later 

than February 22, 2019 to be considered during the preparation of the EA. Commentsreceived, 

including names and addresses of those who comment, will be considered part of the public 

record for this project and will be available for public inspection. Additional information regarding 

the Project may be obtained from Logan Sholar, telephone number (303) 293-5036 and the 

Project website provided below. When available, the EA and other supporting documentation 

will be posted at:

http://www.wrcc.osmre.gov/initiatives/caballoMine.shtm.
Appendix A

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 A-5

United States Department of the Interior

OFFICE OF SURFACE MINING 

RECLAMATION AND ENFORCEMENT

Western Region

1999 Broadway St., Suite 3320

Denver, CO 80202-3050

December 19, 2018

Dear Stakeholders and Interested Parties,

The U.S. Department of the Interior (DOI), Office of Surface Mining Reclamation and 

Enforcement (OSMRE), Western Region Office, will prepare an environmental assessment (EA) 

for the implementation of a federal mining plan for the Caballo West Tract for federal coal lease 

WYW172657 (the Project). In accordance with the Mineral Leasing Act of 1920 (MLA), theDOI 

Assistant Secretary for Land and Minerals Management (ASLM) must approve the Projectbefore 

any mining and reclamation can occur on lands containing leased federal coal. The lease and sale 

of the federal coal included in the Caballo West LBA (WYW172657) was originally evaluated in 

the 2009 South Gillette Area Coal Lease Applications Environmental Impact Statement (2009 

SGAC EIS). The coal was offered for sale in a sealed-bid, competitive lease process on August 

17, 2011. Following determination by BLM that the highest bid at the sale met or exceeded the 

fair market value of the coal within the tract, the bid submitted by Alpha Wyoming Land Company 

was accepted. The lease was subsequently transferred from Alpha Wyoming Land Company to 

BTU Western Resources on July 24, 2012. BTU Western Resources owns and operates the Caballo 

Mine. The coal would be mined using conventional surface-mining methods and shipped from an 

onsite railroad loading facility to various sites within the United States. On November 30, 2015, 

the Wyoming Department of Environmental Quality (WDEQ)/Land Quality Division (LQD) 

approved Caballo Coal Company’s (CCC) application to amend the Mine Permit No. 433 to 

include 1,294 acres, which included the Caballo West Tract.

OSMRE is preparing this EA to evaluate the environmental impacts resulting from the Project, 

pursuant to the requirements of the National Environmental Policy Act of 1969 (NEPA). The 

Caballo Mine is located in Campbell County, Wyoming, approximately 10 miles south-southeast 

of Gillette. The Project is located on federal coal leases administered by the Bureau of Land 

Management (BLM) Casper Field Office and located within the Caballo Mine’s permit area, 

approved in accordance with the Surface Mining Control and Reclamation Act. The amount of 

remaining recoverable federal coal authorized for recovery within currently approved federal 

mining plans is approximately 363.9 million tons (Mt). The Project proposes to add approximately

119.8 Mt of recoverable federal coal. The annual production rate used to calculate the 

environmental impacts resulting from the Proposed Action will be 13.5 million tons per year 

(Mtpy), which is the estimated future annual production rate suggested by CCC and is below the 

maximum permitted production rate of 35 Mtpy set by WDEQ/AQD air quality permit MD-1477. 

CCC started operation in 1976 and the mine will continue to operate until 2042 under the current, 

approved mining plan. Using the estimated 13.5 Mtpy production rate, the Project would extend 

the life of the mine by approximately 8.9 years, to 2051.
Appendix A

A-6 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

The EA will update, clarify, and provide new and additional environmental information for the 

Project that has become available since the 2009 SGAC EIS was approved and the lease was 

issued. As a result of the EA process, OSMRE will determine whether or not there are significant 

environmental impacts related to the Project. An environmental impact statement will be prepared 

if the EA identifies significant impacts. If a finding of no significant impact (FONSI) is reached, 

and pursuant to 30 CFR § 746.13, OSMRE will prepare and submit to the ASLM a mining plan 

decision document recommending approval, disapproval, or conditional approval of the mining 

plan. As required under the Mineral Leasing Act of 1920, the ASLM will approve, disapprove, or 

conditionally approve the federal mining plan document within the mining plan decision 

document.

OSMRE is soliciting public comments on the Project. Your comments will help to determine the 

issues and alternatives that will be evaluated in the environmental analysis. You are invited to 

direct these comments to:

ATTN: Caballo West Tract EA 

C/O: Logan Sholar

OSMRE Western Region 

1999 Broadway, Suite 3320,

Denver, CO 80202-3050

Comments may also be emailed to: osm-nepa-wy@osmre.gov, ensure the subject line reads: 

ATTN: OSMRE, Caballo West Tract EA. Comments should be received or postmarked no later 

than January 19, 2019 to be considered during the preparation of the EA. Comments received, 

including names and addresses of those who comment, will be considered part of the public record 

for this project and will be available for public inspection. Additional information regarding the 

Project may be obtained from Logan Sholar, telephone number

(303) 293-5036 and the Project website provided below. When available, the EA and other 

supporting documentation will be posted at: 

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

Sincerely,

Elizabeth Shaeffer, Manager 

Field Operations Branch

Attachment – Location Map
Appendix A

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 A-7
Appendix A

A-8 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

February 5, 2019 

Dear Stakeholders and Interested Parties,

The OSMRE Western Region website was inaccessible from late December, 2018 through 

January, 2019 due to the government shutdown. Therefore, OSMRE is extending the scoping 

period for the preparation of an Environmental Assessment (EA) for the Caballo Mine West Tract 

new Federal mining plan for an additional 15 days. Scoping comments will be accepted from 

February 7, 2019 to February 22, 2019.

The U.S. Department of the Interior (DOI), Office of Surface Mining Reclamation and 

Enforcement (OSMRE), Western Region Office, will prepare an environmental assessment (EA) 

for the implementation of a federal mining plan for the Caballo West Tract for federal coal lease 

WYW172657 (the Project). In accordance with the Mineral Leasing Act of 1920 (MLA), theDOI 

Assistant Secretary for Land and Minerals Management (ASLM) must approve the Projectbefore 

any mining and reclamation can occur on lands containing leased federal coal. The lease and sale 

of the federal coal included in the Caballo West LBA (WYW172657) was originally evaluated in 

the 2009 South Gillette Area Coal Lease Applications Environmental Impact Statement (2009 

SGAC EIS). The coal was offered for sale in a sealed-bid, competitive lease process on August 

17, 2011. Following determination by BLM that the highest bid at the sale met or exceeded the 

fair market value of the coal within the tract, the bid submitted by Alpha Wyoming Land Company 

was accepted. The lease was subsequently transferred from Alpha Wyoming Land Company to 

BTU Western Resources on July 24, 2012. BTU Western Resources owns and operates the Caballo 

Mine. The coal would be mined using conventional surface-mining methods and shipped from an 

onsite railroad loading facility to various sites within the United States. On November 30, 2015, 

the Wyoming Department of Environmental Quality (WDEQ)/Land Quality Division (LQD) 

approved Caballo Coal Company’s (CCC) application to amend the Mine Permit No. 433 to 

include 1,294 acres, which included the Caballo West Tract.

OSMRE is preparing this EA to evaluate the environmental impacts resulting from the Project, 

pursuant to the requirements of the National Environmental Policy Act of 1969 (NEPA). The 

Caballo Mine is located in Campbell County, Wyoming, approximately 10 miles south-southeast 

of Gillette. The Project is located on federal coal leases administered by the Bureau of Land 

Management (BLM) Casper Field Office and located within the Caballo Mine’s permit area, 

approved in accordance with the Surface Mining Control and Reclamation Act. The amount of 

remaining recoverable federal coal authorized for recovery within currently approved federal 

mining plans is approximately 363.9 million tons (Mt). The Project proposes to add approximately

119.8 Mt of recoverable federal coal. The annual production rate used to calculate the 

environmental impacts resulting from the Proposed Action will be 13.5 million tons per year 

(Mtpy), which is the estimated future annual production rate suggested by CCC and is below the 

maximum permitted production rate of 35 Mtpy set by WDEQ/AQD air quality permit MD-1477.
Appendix A

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 A-9

CCC started operation in 1976 and the mine will continue to operate until 2042 under the current, 

approved mining plan. Using the estimated 13.5 Mtpy production rate, the Project would extend 

the life of the mine by approximately 8.9 years, to 2051.

The EA will update, clarify, and provide new and additional environmental information for the 

Project that has become available since the 2009 SGAC EIS was approved and the lease was 

issued. As a result of the EA process, OSMRE will determine whether or not there are significant 

environmental impacts related to the Project. An environmental impact statement will be prepared 

if the EA identifies significant impacts. If a finding of no significant impact (FONSI) is reached, 

and pursuant to 30 CFR § 746.13, OSMRE will prepare and submit to the ASLM a mining plan 

decision document recommending approval, disapproval, or conditional approval of the mining 

plan. As required under the Mineral Leasing Act of 1920, the ASLM will approve, disapprove, or 

conditionally approve the federal mining plan document within the mining plan decision 

document.

OSMRE is soliciting public comments on the Project. Your comments will help to determine the 

issues and alternatives that will be evaluated in the environmental analysis. You are invited to 

direct these comments to:

ATTN: Caballo West Tract EA 

C/O: Logan Sholar

OSMRE Western Region 

1999 Broadway, Suite 3320,

Denver, CO 80202-3050

Comments may also be emailed to: osm-nepa-wy@osmre.gov, ensure the subject line reads: 

ATTN: OSMRE, Caballo West Tract EA. Comments should be received or postmarked no later 

than February 22, 2019 to be considered during the preparation of the EA. Comments received, 

including names and addresses of those who comment, will be considered part of the public record 

for this project and will be available for public inspection. Additional information regarding the 

Project may be obtained from Logan Sholar, telephone number (303) 293-5036 and the Project 

website provided below. When available, the EA and other supporting documentation will be 

posted at: http://www.wrcc.osmre.gov/initiatives/caballoMine.shtm.

Sincerely,

Elizabeth Shaeffer, Manager 

Field Operations Branch

Attachment – Location Map
Appendix A

A-10 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433
Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

APPENDIX B

PUBLIC SCOPING AND NOTICE OF AVAILABILITY MAILING LISTS

and

PUBLIC SCOPING COMMENT SUMMARIES

and

EA REVIEW COMMENT SUMMARIES and RESPONSES 

(INDIVIDUAL LETTERS RECEIVED HAVE NOT BEEN INCLUDED)

Appendix B

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 B-1

Mailing List

Name Title

Tribes

Vernon Hill Chairman Eastern Shoshone Business Council

Dean Goggles Chairman Northern Arapaho Business Council

Shaun Chapoose Chairperson The Ute Tribe of the Uintah and Ouray Reservation

Harold C. Frazier Chairman Cheyenne River Sioux Tribal Government

Roxanne Sazue Chairwoman Crow Creek Sioux Tribe

Wanda Wells Cultural Affairs Crow Creek Sioux Tribe

Anthony Reider President Flandreau Santee Sioux Tribe

Michael Jandreau Chairman Lower Brule Sioux Tribe

Clair Green Cultural Resources/Public Affairs Lower Brule Sioux Tribe

John Yellow Bird Steele President Oglala Sioux Tribal Council

William Kindle President Rosebud Sioux Tribe

Garryl Rousseau Sr. Vice-Chairman or Acting Chairman Sisseton-Wahpeton Oyate Tribes

Robert Flying Hawk Chairman Yankton Sioux Tribe

Lyman Guy Tribal Chairman Apache Tribe of Oklahoma

Lisa Martin Tribal Council Coordinator Cheyenne-Arapaho Tribes of Oklahoma

Wallace Coffey Chairman Comanche Nation Tribe

Amber Toppah Lady Chairman Kiowa Business Committee

Roger Trudell Chairman Santee Sioux Tribe of Nebraska

Mark Fox Chairman MHA Nation Tribal Council, Three Affiliated Tribes

Dave Archambault II Chairman Standing Rock Sioux Tribe

Vernon Finley Chairman Confederated Salish and Kootenai Tribes of the Flathead

Floyd Azure Chairman Ft. Peck Assiniboine and Sioux Tribes

Harry Barnes Chairman Blackfeet Tribal Business Council

Darrin Old Coyote Chairman Crow Tribal Council

Llevando “Cowboy” Fisher Sr. President Northern Cheyenne Tribal Council

Blaine Edmo Chairman Shoshone-Bannock Tribes of the Fort Hall Reservation

Federal, State, and Local Agencies

Doug Miyamoto Director Wyoming Department of Agriculture

Todd Parfitt Director Wyoming Department of Environmental Quality

Mark Rogaczewski District 3 Supervisor WDEQ Land Quality Division

David Waterstreet MANAGER WDEQ WATERSHED PROTECTION SECTION

Scott Talbott Director Wyoming Department of Game and Fish

Mary Hopkins SHPO Wyoming Historic Preservation Office, SHPO

Milward Simpson Director Wyoming Department of Parks and Cultural Resources

Stephanie Pyle Senior Administrator Wyoming Department of Public Health

Bridget Hill Director Office of State Lands and Investment

Josh Van Vlack State Forester Wyoming Forestry Division

Bill Panos Director Wyoming Department of Transportation

Brian Lovett Executive Director Wyoming Industrial Siting Agency

Erin Campbell Director/State Geologist Wyoming Geological Survey

Dan Noble Director Wyoming Department of Revenue
Appendix B

B-2 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

Name Title

Mark W. Watson Director Wyoming Oil and Gas Conservation Commission

Patrick T. Tyrrell State Engineer Wyoming State Engineer’s Office

Domenic Bravo Division Administrator Wyoming State Parks, Historic Sites & Trails Division

Harry C. LaBonde Director Wyoming Water Development Commission

Wyoming Office of the Governor

John Cox Director Wyoming Department of Workforce Services

Diane Shober Executive Director Wyoming Office of Tourism Board

Alan B. Minier Chairman Wyoming Public Service Commission

Economic Analysis Division Wyoming Department of Administration and Information

Mark Gordon Wyoming State Treasurer Office of the State Treasurer

Nancy Vehr Air Quality Administrator WY DEQ Air Quality Division

Sarah Needles Cultural Resources Division Administrator WY State Historic Pres Office

Kyle Wendtland LQD Administrator Wyoming LQD - DEQ

Wyoming State Board of Land Commissioners

Tony Glover Manager WY Dept of Workforce & Planning, Research & Planning

Chris Wichmann Manager Wyoming Dept of Agriculture - Natural Resources &

Mark Christensen Campbell County Commissioners

Dr. Garry Becker Campbell County Commissioners

Matt Avery Campbell County Commissioners

Rusty Bell Campbell County Commissioners

Micky Shober Campbell County Commissioners

Campbell County Airport

Keith Bowar Chief Building Official Campbell County Building Division

Megan Nelms AICP, County Planner & Zoning Campbell County Planning & Zoning Division

David King CCEMA Coordinator Campbell County Emergency Management

Bill Shank Fire Chief Campbell County Fire Department

Dave McCormick Executive Director Campbell County Parks and Recreation

Kevin King, P.E. Director Campbell County Department of Public Works

Kevin F. Geis, P.E. Executive Director Campbell County Road & Bridge

Quade Schmelzle Director Campbell County Weed & Pest

Campbell County Conservation District

Campbell County School District 1

Executive Director Campbell County Economic Development Corporation

Campbell County Public Land Board

Tom Langston Gillette Department of Commercial Development

Louise Carter-King Mayor City of Gillette

Kevin McGrath City Council City of Gillette

Tim Carsrud City Council City of Gillette

Robin Kuntz City Council City of Gillette

Dan Barks City Council City of Gillette

Billy Montgomery City Council City of Gillette

Ted Jerred City Council City of Gillette

Dustin Hamilton Development Services Director City of Gillette
Appendix B

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 B-3

Name Title

Sawley Wilde Public Works Director City of Gillette

Kendall Glover Director of Utilities City of Gillette

Jim Hloucal Chief of Police City of Gillette

Pam Boger Administrative Services Director City of Gillette

Cartier Napier City Administrator City of Gillette

Hon. Matthew H. Mead Governor Wyoming Governor

Representative Scott Clem District HD31 Wyoming Legislature

Representative Roy Edwards District HD53 Wyoming Legislature

Representative Bill Pownall District HD52 Wyoming Legislature

Senator Ogden Driskill District SD01 Wyoming Legislature

Senator Michael Von Flatern District SD24 Wyoming Legislature

Darryl LaCounte Regional Director Rocky Mountain Regional Office, Bureau of Indian Affairs

Carlie Ronca Area Manager Wyoming Area Office, Bureau of Reclamation

Wyoming Regulatory Office, US Army Corps of

Mary Jo Rugwell State Director Wyoming State Office, Bureau of Land Management

Stephanie Connolly High Plains District Manager High Plains District Office, Bureau of Land Management

Mitchell Leverette Division Chief Bureau of Land Management

Jamie Connell State Director Montana State Office, Bureau of Land Management

Todd Yeager Miles City Office, Bureau of Land Management

Duane Spencer Buffalo Field Office, Bureau of Land Management

Rhen Etzelmiller Casper Field Office, Bureau of Land Management

Library, Bureau of Land Management

Coal Coordinator Montana State Office, Bureau of Land Management

Coal Coordinator Wyoming State Office, Bureau of Land Management

Lawrence S. Roberts Acting Assistant Secretary Bureau of Indian Affairs

Environmental Division US Air Force Headquarters/CEVP

NPS

NPS - Air Quality

NPS Air Resources Division

NPS 2310

U.S. Department of Energy

Shaun McGrath Administrator US EPA, Region 8

Mark Sattelberg Field Supervisor Wyoming Ecological Services Field Office, US Fish and

Dennis Jaeger Forest Supervisor's Office Thunder Basin National Grassland, USDA Forest Service

Devils Tower National Monument, National Park Service

Astrid Martinez State Conservationist Wyoming State Office, Natural Resources Conservation

Marcello Calle Office of Surface Mining Reclamation and Enforcement

Advisory Council on Historic Preservation

US Army Corps of Engineers

US EPA

Ecological Services US Fish and Wildlife Service

US Geological Survey

BLM Cooperator Lead USDA-FS Douglas Ranger District
Appendix B

B-4 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

Name Title

USGS Water Resources Division

US Fish and Wildlife Service, Ecological Services

US Army Corps of Engineers

US EPA

US Geological Survey

Michael Enzi US Senate Gillette Office

John Barrasso US Senate Casper Office

Liz Cheney US House of Representatives Casper Office

Businesses and Individuals

Contura Wyoming Land, LLC

Peabody Caballo Mining, LLC

Rourke, Linda K., Trustee % First Interstate

Rourke, Paul Donald, et al

State of Wyoming Commissioner of Public

Bertalot, Dusty

Bertalot, Kenneth K. and Angela M.

BTU Western Resources, Inc.

Conkey, Bonnie A.

Edwards, Joseph Leon

Johnson, Steven E. and Debora

Love, Harry E., Jr.

Miller, Gary D. and Patty

Miller, Glenn E. and Susan C. Mirich-Miller

Mark Thrall Belle Ayr Mine

H.A. True President, Belle Fourche Pipeline Company

Mitchell J. Reneau VP Land, Bill Barrett Corporation

Biodiversity Conservation Alliance

BNSF Railway Company

Buckskin Mine-Kiewit Mining Group

Casper Star Tribune

Amy M. Atwood Center for Biological Diversity

John Trummel Cloud Peak Energy

Converse County Commission

Dr. Dan Espelan Converse County School District #1

Kirk M. Hughes Converse County School District #2

Paul W. Musselman Converse Cty, Special Projects

Cordero Rojo Mine

Defenders of Wildlife

Devils Tower National Monument

Matt Adelman Publisher, Douglas Budget

Environmental Policy and Culture Program

Federation for North American Wild Sheep

Energy Reporter Gillette News-Record
Appendix B

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 B-5

Name Title

Steve Bullock Governor of Montana

Scott Child Interwest Mining Company

Joe Mehl Kiewit Mining Group Inc

Jim McLeland M&K Oil Company Inc

Greg Julian Mineral Management Service

Hal Quinn National Mining Association

National Wildlife Federation

Natural Resources Defense Council

Shannon Anderson Powder River Basin Resource Council

Phil Dinsmoor Powder River Coal Company

Bob Comer Rocky Mtn Region Solicitor

Peter Morgan Sierra Club

Lecia Craft Thunder Basin Coal Company

Ralph Kingan Mayor, Town of Wright

Roger Miller President, Trout Unlimited

Lance Fritz President, Chief Executive Officer, Union Pacific Railroad

US West Communications (Qwest Corp.)

Jason M. Ryan Business Analytics Director, US Western Surface

Wendi Chatman UW Libraries

Taylor Jones WildEarth Guardians

Mike Evers WWC Engineering

WY Business Council

Bill Schilling Wyoming Business Alliance

Matt Grant Wyoming Mining Association

Gary Wilmont Wyoming Outdoor Council

Niels Hansen Wyoming Stock Growers Assoc

Steve Kilpatrick Wyoming Wildlife Federation

Amy Wallop-Hendrickson Wyoming Wool Growers Association, Executive

Mike McCraken Publisher Wyoming-Tribune Eagle

Katie Parker Yates Petroleum Corp et al
Appendix B

B-6 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

Caballo West Tract EA Public Outreach (Scoping) Comments Summary

Comment 

Date

Water 

Quality

Air 

Quality Wildlife

Level of 

NEPA/ 

NEPA

Process

Reclamation/ 

Self Bonding

Climate 

Change/ 

Global 

Warming

Transportation Pro 

Mining

# of 

Comments

1/10/19 1 1

1/11/19 1 1 2

1/18/19 0

1/18/19 1 1 1 1 1 5

1/18/19 0

1/18/19 1 1

1/22/19 1 1 1 1 1 6

2/21/19 1 1

4 3 1 2 1 2 1 1 13
Appendix B

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 B-7

Commenter: Wyoming Game and Fish Department

Comment: The staff of the Wyoming Game and Fish Department (Department) has reviewed 

the proposed Environmental Assessment and Finding of no Significant Impact for the Caballo Mine 

West Tract Federal Mining Plan Modificatoin (WYW172657) located in Campbell County. We 

have no terrestrial or aquatic concerns pertaining to this mining plan modification.

Response: Noted

Commenter: Wyoming Department of Transportation

Comment: Thank you for the opportunity to comment but we have no concerns at this time.

Response: Noted

Commenter: Environmental Defense Fund, Institute for Policy Integrity at New York 

University School of Law, Montana Environmental Information Center, WildEarth 

Guardians

Comment: The Caballo Mine is located in the Powder River Basin. The Caballo Mine West Tract 

extension would extend the life of the mine by approximately nine years, from 2042-2051, and 

increase the amount of coal mined from an average of 10.1 million tons per year to approximately

13.5 tons per year. OSM estimates and quantifies direct upstream, indirect, and downstream 

greenhouse gas emissions from the additional coal mining, with downstream emissions amounting 

to over 23 million tons of carbon dioxide equivalent each year, extending decades into the future.3 

Yet the EA does not include a monetized estimate of any of the actual, real-world climate damages 

those emissions will produce. When compared to the no action alternative, the scenario that OSM 

proposes would result in billions of dollars in additional climate impacts.

OSM uses faulty reasoning to defend why it has chosen not to use the social cost of greenhouse 

gases metric to monetize the plan’s emissions. OSM’s arguments are wrong, and these comments 

explain why OSM reasoning is flawed and how OSM has violated its obligations under the National 

Environmental Policy Act (NEPA). Specifically, we make the following points:

1. Application of the social cost of greenhouse gases is not limited to rulemakings; NEPA 

requires agencies to fully and accurately estimate environmental, public health, and social 

welfare differences between alternatives, and the social cost of greenhouse gases is the 

best available tool to compare the climate impacts of alternatives;

2. Executive Order 13,783 does not bar agencies from using the same methodology and 

inputs applied by the Interagency Working Group (IWG) to develop its best estimates of 

social cost of greenhouse gases and, in fact, by requiring agencies to use best practices, 

the Executive Order would point agencies toward the same or higher values of global 

climate damages as calculated by the IWG;

3. Although NEPA does not require a formal cost-benefit analysis, the statute does require 

a “reasonably thorough discussion” and “necessary contextual information” on real-world 

climate impacts and their significance. The social cost of greenhouse gases provides such 

information;
Appendix B

B-8 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

4. OSM monetized a number of other effects of the program, including employment and 

labor income, and must give climate effects the same consideration. When an agency 

monetizes a proposed action’s potential benefits—as OSM does here—the potential 

climate costs must be treated with proportional rigor. Additionally, simply because not 

every effect can be monetized does not mean that monetization is not a useful analytical 

tool.

5. OSM inaccurately claims that the SCC is not applicable to a project of this duration; the 

SCC should be applied to annual emissions for every year that emissions from the project 

occur in order to assess the magnitude of the project’s climate impacts.

Response: 

1. The “social cost of carbon” protocol (SCC) was developed by a Federal Interagency 

Working Group (IWG), to assist agencies in addressing EO12866, which requires 

Federal agencies to assess the cost and the benefits, associated with GHG emissions, 

of proposed regulations as part of their regulatory impact analyses This action is not 

a rulemaking for which the SCC protocol was originally developed.

2. On March 28, 2017, the President issued EO 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 EO further directed agencies to ensure that estimates of the social cost of GHGs 

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-level decisions, so there is no EO requirement to 

apply the SCC protocol to project-level decisions.

3. 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). The SCC protocol estimates economic costs associated with an increase in 

CO2 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 

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 

expressed in a broad range, reflecting a degree of uncertainty that greatly diminishes the 

SCC’s utility as an input to the Secretary’s decision making. For example, in a previous 

environmental impact statement, OSMRE 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 8.9 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, OSMRE’s ability to evaluate 
Appendix B

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 B-9

these impacts on a project-level would be doubtful1 (Pindyck 2013, Hope 2013, Anthoff 

and Tol 2013, Nordhaus 2014, and Waldhoff et al. 2011, 2014). 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.

4. 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 would 

change the quality of the local community. Economic impact is distinct from “economic 

benefit” as defined in economic theory and methodology (Watson, Wilson, Thilmany, 

and Winter 2007), and the socioeconomic impact analysis required under NEPA is 

distinct from an economic cost-benefit analysis, which is not required.

5. The SCC protocol does not measure the actual incremental impacts of a project on the 

biophysical environment at a specific geographical location and does not include all 

damages or benefits from carbon emissions.

Given the uncertainties associated with assigning a specific and accurate social cost of carbon estimate 

resulting from 8.9 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 

state and U.S. GHG emission inventories, as discussed in section 4.4.5.

Section 4.4.5 and 4.4.6. specifically evaluate the direct and indirect effects of the Proposed 

Action and clearly includes the estimated direct and indirect impacts from GHG emissions 

related to the Proposed Action. Without having a specific tool to identify project-level 

impacts on global climate, OSMRE chose to disclose the Proposed Action-related GHG 

emissions in the context of state and national GHG emissions to provide the public and 

decision maker with relevant information for potential impacts to climate. OSMRE has 

determined that the existing analysis is adequate to inform the decisionmaker of potential 

impacts of the Proposed Action.

Commenter: Sierra Club, WildEarth Guardians, Center for Biological Diversity

 1 This conclusion is supported in the February 2018 BLM Regulatory Impact Analysis for the Proposed Rule to Rescind or Revise Certain 

Requirements of the 2016 Waste Prevention Rule (BLM 2018), noting that “[t]he scientific and economics literature has further 

explored known sources of uncertainty related to estimates of the social cost of carbon and other greenhouse gases noting further 

that researchers have examined the sensitivity of Integrated Assessment Models (IAMs) and the resulting estimates to different 

assumptions embedded in the models (see, e.g., Pindyck 2013, Hope 2013, Anthoff and Tol 2013, Nordhaus 2014, and Waldhoff et al. 

2011, 2014). BLM further spoke to the “additional sources of uncertainty that have not been fully characterized and explored due to 

remaining data limitations, concluding that” [a]dditional research is needed to expand the quantification of various sources of 

uncertainty in estimates of the social cost of carbon and other greenhouse gases (e.g., developing explicit probability distributions for 

more inputs pertaining to climate impacts and their valuation). On damage functions, other experts have found that those used in 

most IAMs have no theoretical or empirical foundation, claiming that the overall model is able to “obtain almost any result one 

desires” (Pindyck 2013). Naturally, the indeterminate amount of uncertainty surrounding the IAMs used to approximate social costs 

for specific greenhouse gas emissions merits additional research and analysis and further peer-review in order to better ascertain the 

best available science and economics in accordance with E.O. 13783.” BLM’s discussion is in the context of a rulemaking for which the 

SCC was developed. The uncertainties regarding the applicability of social cost of carbon by OSMRE in the context of a specific project 

is even greater.
Appendix B

B-10 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

Comment #1: Under both long-standing NEPA regulations and OSMRE’s own internal NEPA 

guidance, OSMRE must prepare an Environmental Impact Statement (“EIS”) to analyze the 

environmental impacts of the Caballo West proposal.

Response #1: OSMRE reviewed Peabody Caballo Mining, LLC’s proposed action against the DOI 

Departmental Manual, Series 31, Part 516, Chapter 13, Section 13.4 titled Major Actions Normally 

Requiring an EIS (516 DM 13). The BLM released a final environmental impact statement for the South 

Gillette Area Coal Lease Applications (SGAC EIS) in August of 2009 which included an analysis of

impacts resulting from leasing and mining of the Caballo West tract at the Caballo Mine. The analysis 

of potential impacts in the SGAC EIS did not identify significant impacts to any resources within the 

established analysis areas. OSMRE recognizes that the area proposed to be mined in the Caballo West 

Tract includes 866.7 acres of disturbance and the annual full production for the entire mine is expected 

to remain at 13.5Mt during the mining of Federal coal in the Caballo West Tract. OSMRE also 

understands that the proposed project would extend the life of the mine by 8.9 years with reclamation 

likely continuing beyond 15 years. OSMRE has recently completed EAs for other Federal coal mining 

projects in this region of Wyoming wherein the amount of coal removal and surface acreage 

disturbance were greater than what would occur under the proposed mining of Federal coal in the 

Caballo West Tract at the Caballo Mine. These recently completed OSMRE EAs also reflect mining and 

reclamation operations that will occur for 15 years or more. Significant impacts were not identified 

during the analysis for these other OSMRE EAs. Due to the lack of significant impacts identified in the 

recent Cordero Rojo Duvall Amendment EA and the Belle Ayr North EA, OSMRE determined that an 

EIS was not initially required. 516 DM 13 explicitly recognizes that OSMRE may choose not to prepare 

an EIS for any of the listed actions, and “If for any of these actions it is proposed not to prepare an EIS, 

an EA will be prepared and handled in accordance with Section 1501.4(e)(2)).” OSMRE has completed 

the EA process and has not identified significant negative impacts.

Comment #2: NEPA requires OSMRE to analyze and disclose the cumulative climate impact of 

mining at Caballo West when added to similar past, present, and reasonably foreseeable future 

mining proposals. Here, OSMRE attempts to dodge any meaningful cumulative climate analysis.

Instead, it simply lists generally expected regional climate impacts, completely divorced from any 

contribution from Department of Interior (“DOI”) actions, and asserts that it is impossible to 

prepare a cumulative climate analysis for any project anywhere.

Despite the global nature of climate change, OSMRE could nonetheless consider the cumulative 

climate impact of its decisions by calculating the total direct and indirect emissions associated with 

similar OSMRE decisions in the same area. OSMRE has made no attempt to quantify GHG 

emissions associated with Caballo West mining when combined with other similar mining 

proposals in the Powder River Basin or other OSMRE approved mine plans. In contrast to its 

approach to cumulative climate impacts, the Draft EA provides a cumulative air quality assessment 

of air emissions at the Caballo Mine, combined with PM10 and PM2.5 emissions from the nearby 

Belle Ayr, Coal Creek, and Cordero Rojo mines from 2010-2017, as well as for the 2016-2035 

time period.

It is important that OSMRE analyze the impacts of mining at Caballo West consistent with the 

“hard look” NEPA requires, in order to ensure DOI can make an objective, informed decision on 

the proposed coal lease expansion in Wyoming.

Response #2: Section 4.4.6.2 of the EA states that “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.” Section 4.4.5 presents emissions related to the Proposed Action in 

the context of total U.S. emissions. OSMRE, where appropriate and not overly speculative, 
Appendix B

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 B-11

included data from the most current future climate modeling (Section 4.4.6.2 of the EA) as in the 

case with the Air Quality and Climate Change discussion in Chapter 4 allowing the decision maker 

to evaluate potential impacts, such as increased maximum temperatures and decreased maximum 

precipitation, associated with the Proposed Action using representative or predicted emissions.

Comment #3: OSMRE must acknowledge the scientific consensus on the urgent need to cut U.S. 

greenhouse gas emissions.

Since the 2009 SGAC EIS, two National Climate Assessments have been released by the U.S. 

Global Change Research Program (“USGCRP”), in 2014 and 2018, respectively. With an 

overwhelming amount of climate evidence published within the past 10 years, OSMRE must 

acknowledge the findings of recent climate reports, including the Fourth National Climate 

Assessment of 2018, as well as two other studies published last year by the Intergovernmental 

Panel on Climate Change (“IPCC”) and the U.S. Geological Survey. Additionally, information 

published in January of this year specifically points out the urgent need for land management 

agencies to say “no” to the fossil fuel industry and for elected officials at all levels to steer the 

industry towards equitable and orderly phase-out.

OSMRE must both acknowledge that a new, far more robust set of scientific documents exists 

now compared to BLM’s 2009 EIS that the Draft EA tiers to, and must disclose that these scientific 

documents conclude that we need to dramatically reduce greenhouse gas emissions within a 

dangerously small window of time in order to avoid the worst effects of climate disruption.

Response #3: While this EA does incorporate by reference descriptions of the affected 

environment and certain analyses from the 2009 SGAC EIS, analyses of impacts to certain 

resources like air quality and climate have been updated to reflect new information since 

completion of the 2009 SGAC EIS. OSMRE has determined that this EA adequately discloses the 

intensity of potential impacts to the environment, and climate specifically, based on the analyses in 

Ch. 4 and Section 4.4.5, respectively. Section 4.4.5 of the EA evaluates the reasonably foreseeable 

direct and indirect effects of the Proposed Action and clearly includes the estimated direct and 

indirect impacts from GHG emissions related to the Proposed Action. The EA’s analysis is 

sufficiently thorough to inform the decisionmaker and the public of potential impacts of the 

Proposed Action.

Comment #4: OSMRE must discard the perfect substitution theory in order to properly analyze 

the market and climate impacts of the proposed project. In the 2009 South Gillette Area Coal 

Leasing EIS, BLM denied that the Caballo coal lease would have any contribution to climate change. 

BLM claimed, incorrectly, that expanding federal coal leases would have no impact on the amount 

of coal mined in the U.S. or on the amount of carbon dioxide emitted from burning coal to 

generate electricity. OSMRE’s Draft EA is silent on substitution, leaving the impression that 

OSMRE endorses the climate analysis in the 2009 EIS, because OSMRE has “incorporated by 

reference analyses included in the 2009 South Gillette [EIS].”

Under this perfect substitution theory, which has been squarely rejected by every federal court to 

consider the issue, even if federal agencies were to deny a particular coal lease, the same amount 

of coal would ultimately be mined elsewhere, and thus the greenhouse gas emissions from our 

electricity sector would remain the same regardless of agency decisions. The perfect substitution
Appendix B

B-12 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

theory defies economics and ignores the fundamental economic principles of supply and demand, 

denying the public and decisionmakers the opportunity to review and consider a project’s climate 

impacts, as required by NEPA. Yet OSMRE fails to even address substitution in the Draft EA, thus 

leaving in place the unsupported and incorrect perfect substitution theory espoused in the 2009 

South Gillette Coal Leasing EIS, which OSMRE tiers to here.

OSMRE’s failure to study these market and climate effects of its decision is even more glaring 

because there are readily-available models that would allow the agency and the public to 

understand the substitution effects and GHG emissions differences between the Action and No 

Action alternatives.

Under NEPA, agencies must provide a clear basis for choice among considered alternatives, and in 

particular here OSMRE must distinguish between the climate impacts of Action and No Action 

alternatives. 42 U.S.C. §§ 4332(2)(C), 4332(2)(E), and 40 C.F.R. §§ 1502.14(f), 1508.9(b). NEPA

requires agencies to use the tools available to them in order to ascertain essential information or 

explain why they cannot do so. 40 C.F.R. § 1502.22. Under the applicable NEPA regulations, if an 

agency intends not to include essential information in its NEPA review, it “shall” explain (1) why 

such essential information is incomplete or unavailable; (2) its relevance to reasonably foreseeable 

impacts; (3) a summary of existing science on the topic; and (4) the agency’s evaluation based on 

any generally accepted theoretical approaches. Id. § 1502.22(b). Given that other agencies have 

long used energy models to analyze market and climate impacts of their proposals, that 

information is plainly “available” within the meaning of the regulation, and OSMRE must utilize 

these available tools to understand the impacts of various alternatives here.

OSMRE must address the key climate question: whether there is a measurable difference in 

greenhouse gas emissions between approving and rejecting this approximately 120 million ton coal 

mine expansion. Without such an answer, neither OSMRE nor the public can adequately 

distinguish between the climate impacts of the Action and No Action alternatives. In the context 

of climate change, OSMRE must, at the bare minimum, analyze and disclose the difference in 

greenhouse gas emission levels between considered alternatives, including the No Action 

alternative. Here, by adhering to an outdated EIS that recites an inaccurate and judicially- rejected 

economic assumption, OSMRE improperly downplays the climate impacts of its decision and 

violates NEPA.

Response #4: OSMRE is not relying on the “perfect substitution theory” in the Caballo West 

Tract EA based on the fact that all potential direct, indirect and cumulative impacts to climate 

resulting from mining, transporting and burning coal as would be approved under the Proposed 

Action have been disclosed. A full-scale supply and demand market analysis is not required and is 

outside the scope of this EA. Section 4.4.5 of the EA discloses and quantifies the difference in 

greenhouse gas emissions impacts between the Proposed Action Alternative and the No Action 

Alternative. The Proposed Action would result in impacts that are moderate and would extend 

those impacts approximately 8.9 years beyond the current life of the mine. The impacts directly 

resulting from GHG emissions under the No Action Alternative would be similar to those under 

the Proposed Action but would not be extended by approximately 8.9 years. While annual CO2e 

emissions would remain the same as the Proposed Action for approximately 24 years, the life of 

mine CO2e emissions would decrease by approximately 37 percent as a result of the No Action 

Alternative, based on 8.9-fewer years of combustion of Caballo Mine coal. Using the 2016 U.S. 

estimate for comparison purposes, the estimated annual CO2e contribution from the Caballo 

Mine coal
Appendix B

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 B-13

was approximately 0.27 percent. Under the Proposed Action, the estimated CO2e contribution 

would be approximately 0.36 percent of the U.S. total CO2e emissions. The direct and indirect 

effects of the Proposed Action on annual CO2e emissions would be moderate and short-term.

Regarding the potential cumulative impacts on climate, the current tools for simulating climate 

change generally focus on global and regional-scale modeling. The IPCC Fifth Assessment Report 

(AR5), issued in 2013, makes certain conclusions about the future impacts of GHG emissions on 

climate change based largely on several modeling analyses that evaluate the natural systems and 

feedback mechanisms contributing to climate variability over the entirety of the Earth. The modeling 

analyses consider a range of global GHG emissions scenarios known as Representative 

Concentration Pathways (RCPs). The RCPs evaluate different pathways of GHG emissions and 

atmospheric concentrations, air pollutant emissions, and land use patterns. 

The anthropogenic GHG emissions represented in each scenario are influenced by assumptions of 

population size, economic activity, lifestyle, energy use, land use patterns, technology, and climate 

policy. The RCPs include a stringent mitigation scenario (RCP2.6), two intermediate scenarios 

(RCP4.5 and RCP6.0) and one scenario with very high GHG emissions (RCP8.5) (IPCC, 2014 pg. 8). 

A “lower scenario” (RCP4.5), which assumes lower emissions and concentrations of GHGs and 

aerosols and projects a lower change in radiative forcing by 2100; and (2) a “higher scenario” 

(RCP8.5), which assumes a continued dependence on fossil fuels, higher GHG emissions and 

concentrations, and projects a larger change in radiative forcing by 2100. These scenarios 

correspond to atmospheric concentrations of CO2 by the year 2100 of 538 ppm for RCP4.5 and 

936 ppm for RCP8.5. Each RCP scenario has been used in multiple global integrated assessment 

models to make predictions about future warming associated with those GHG emissions. For 

example, by 2050, global surface temperature change is projected to likely range from 0.5 to 2.0 

degrees Celsius (°C) for the high emissions scenario (RCP8.5), but likely to range from 0.3 to 1.0°C 

for the low emissions scenario (RCP2.6) (IPCC, 2014 pg. 59-60). 

According to the EPA (2018) in 2016 (the most recent year of available CO2 data at this time), 

CO2e emissions in the U.S. totaled 6,511.3 million metric tons. The estimated CO2e contribution of 

the U.S. emissions would be approximately 13% of the total global CO2e emissions. In 2018, the 

United States Geological Survey (USGS) published a report titled “Federal Lands Greenhouse Gas 

Emissions and Sequestration in the United States: Estimates for 2005–14” (USGS 2018) on GHG 

emissions from extraction and use of fossil fuels produced on Federal lands and GHG sinks (carbon 

storage by terrestrial ecosystems) on Federal lands in the US. In 2014, nationwide emissions from 

fossil fuels (oil, gas, and coal) extracted from Federal lands were 1,279.0 MMmt carbon dioxide 

equivalents (CO2e) of carbon dioxide, 47.6 MMmt CO2e of methane, and 5.5 MMT CO2e of nitrous 

oxide based on 100-year GWPs (USGS, 2018 pg. 6). In 2014, carbon storage by terrestrial 

ecosystems on Federal lands in the conterminous United States (not including Alaska and Hawaii) 

was 83,600 MMmt CO2e. Soils stored 63 percent of carbon, with vegetation and dead organic 

matter storing 26 percent and 11 percent, respectively (USGS, 2018 pg. 12). Between 2005 and 

2014, the annual rate of net carbon uptake by terrestrial ecosystems in the conterminous US ranged 

from a sink (sequestration) of 475 MMmt tons of CO2e per year to a source (emission) of 51 MMmt 

CO2e per year due to changes in climate/weather, land use, land cover change, wild fire frequency, 

and other factors. Terrestrial ecosystems on Federal lands sequestered an average of 195 MMmt 

CO2e per year nationally between 2005 and 2014 (USGS, 2018 pg. 13-17).
Appendix B

B-14 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

According to the IPCC’s Fourth National Climate Assessment, changes in average global temperature 

are predicted to be in the range of 0.3 to 2.0°C by 2050, warming rates can vary across the globe 

and are greater at higher latitudes due in part to reduced snow cover and reduced albedo. For 

example, in the Northern Great Plains, Montana, Wyoming, North Dakota, South Dakota, and 

Nebraska climate model predictions show a warmer future, with conditions becoming consistently 

warmer in two to three decades and temperatures rising steadily towards the middle of the century, 

irrespective of the climate scenario modeled, with predicted temperature increases of between 2 to 

4°F (approx. 1-2oC) projected by 2050 under the lower emissions scenario. 

To discuss the cumulative impacts of GHG emissions for the project area, regional-scale projected 

impacts are discussed for Campbell County, WY in Section 4.4.6.2. The USGS National Climate 

Change Viewer (USGS 2016) was used to evaluate potential climate change at the county level. The 

viewer provides data showing projections of future climate trends under RCP emission scenarios. 

The low emissions scenario (RCP4.5) and the higher emissions scenario (RCP8.5) are based on 

projections from 30 different global climate models. Projected changes to the maximum and 

minimum temperature and precipitation for Campbell County are presented to assess cumulative 

impacts from GHG emissions. Generally, the RCP4.5 and RCP8.5 scenarios forecast similar levels of 

climate impacts in the region over the next few decades; however, impacts over the next century 

diverge significantly. Because of uncertainties in the climate models, especially toward the end of the 

century, the impacts projected represent a forecast but are not certain to occur at the magnitudes 

projected. 

Overall, the RCP8.5 scenario representing the higher emission scenario results in higher seasonal 

average maximum and minimum temperature projections over the century, in comparison to the 

RCP4.5 scenario. However, both scenarios project an increase over the historical average over the 

next century. Assuming the Proposed Action extends the life of the project by 8.9 years, the 

associated emissions related to the project would occur from 2042-2051. The temperature 

projections for both scenarios around the mid-century are fairly consistent with most of the 

divergence in the scenarios being realized in the latter half of the century. By the time the project 

emissions occur, the seasonal maximum and minimum temperatures in Campbell County are 

projected to increase by roughly 6.5 and 6.3°F based on the most aggressive global climate change 

model. 

Because the EA quantifies total GHG emissions from the Proposed Action, it is possible to compare 

those emissions to the global GHG emissions estimate for 2010 in the AR5. Under the Proposed 

Action, the estimated CO2e contribution would be approximately 0.05% of the total global CO2e 

emissions. GHG emissions resulting from the Proposed Action would contribute to global 

atmospheric concentrations of GHG emissions; however, the degree to which the emissions from 

8.9 additional years of mining, transporting and burning this Federal coal would contribute to 

cumulative climate change impacts would not be significant. 

Further, the human and natural causes of climate change, and the impacts of climate change, are 

global. GHG emissions do not remain localized but become mixed with the general composition of 

the Earth’s atmosphere. On a global scale, the GHG emission contribution of any single geographic 

subunit (such as a SMCRA-delegated State Regulatory Authority or OSMRE regional office) or 

source (such as federal minerals) on a subnational scale is dwarfed by the large number of 

comparable national and subnational contributors. The relative contribution of GHG emissions from 

production and consumption of Federal minerals will vary depending on contemporaneous changes 

in other sources of GHG emissions. A single subnational contributor is very unlikely to influence 
Appendix B

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 B-15

global cumulative emissions. Therefore, the analysis in this EA does not separate the contribution of 

the Proposed Action’s GHG emissions to global climate change impacts from the multitude of other 

past, present, and RFFAs that have produced or would produce or mitigate GHG emissions. At 

present, the climate change research community has not yet developed tools for evaluating or 

quantifying endpoint impacts attributable to the emissions of GHGs from a single source. 

Nevertheless, each source contributes, on a relative basis, to global emissions and long-term climate 

impacts. OSMRE has determined that the analysis presented in this EA uses the best available data 

and tools and is adequate to inform the decisionmaker and the public of the potential cumulative 

impacts of the Proposed Action.

Comment #5: OSMRE must evaluate the significance of greenhouse gas emissions by using 

available methodologies. Once OSMRE accurately discloses the amount of the greenhouse gas 

emissions associated with this mine expansion, it must also assess the impact that those emissions 

have on the environment. The social cost of carbon protocol (often abbreviated as “SCC” in 

agency documents) is an appropriate tool for OSMRE to use for this assessment. The social cost of 

carbon provides an estimate of the economic damage, in dollars, caused by each incremental ton 

of carbon dioxide emitted into the atmosphere, including impacts such as increased drought, 

wildfires, decreased agricultural productivity, and sea level rise, among others. By translating 

climate impacts, and tons of greenhouse gasses in particular, into dollars, the social cost of carbon 

offers OSMRE an easy to use and understandable tool that would allow the public and 

decisionmakers to better understand the climate impacts of OSMRE’s decision here.

One of the measuring standards available to the agency for analyzing the magnitude and severity of 

OSMRE-related fossil fuel emissions is by applying those emissions to the remaining global carbon 

budget. A “carbon budget” offers a cap on the remaining stock of greenhouse gasses that can be 

emitted while still keeping global average temperature rise below scientifically-backed warming 

thresholds – beyond which climate change impacts may result in severe and irreparable harm to 

the biosphere and humanity. Utilizing carbon budgets would offer OSMRE a methodology for 

analyzing how the proposed mine expansion and the continued coal combustion from the Caballo 

West tract may affect the country’s ability to meet recognized greenhouse gas emission reduction 

targets.

Response #5: Section 4.4.5 specifically evaluates the direct and indirect effects of the Proposed 

Action and clearly includes the estimated direct and indirect impacts from GHG emissions related 

to the Proposed Action. The Proposed Action would result in impacts that are moderate and 

would extend those impacts approximately 8.9 years beyond the current life of the mine. The 

impacts directly resulting from GHG emissions under the No Action Alternative would be similar 

to those under the Proposed Action but would not be extended by approximately 8.9 years.

While annual CO2e emissions would remain the same as the Proposed Action for approximately 

24 years, the LOM CO2e emissions would decrease by approximately 37 percent as a result of the 

No Action Alternative, based on 8.9-fewer years of combustion of Caballo Mine coal. Using the 

2016 U.S. estimate for comparison purposes, the estimated CO2e contribution from the Caballo Mine 

coal was approximately 0.27 percent. Under the Proposed Action, the estimated CO2e contribution 

would be approximately 0.36 percent of the U.S. total CO2e emissions. The direct and indirect effects 

of the Proposed Action on annual CO2e emissions would be moderate and short-term.

A carbon budgeting analysis is not required to determine if significant impacts related to GHG 

emissions are occurring and is outside the scope of this EA. OSMRE, where appropriate and not overly 

speculative, included data from the most current future climate modeling (Section 4.4.6.2 of the 

EA) as in the case with the Climate discussion in Chapter 4, allowing the decision maker to evaluate 

potential impacts such as increased maximum temperatures and decreased maximum precipitation

associated with the Proposed Action using representative and predicted emissions.
Appendix B

B-16 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

Further, 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 the 

agency did not undertake one here; and 4) because the full social benefits of coal-fired energy 

production have not been monetized, quantifying only the costs of GHG emissions will provide 

information that is both potentially inaccurate and not useful. The EA’s analysis is sufficiently 

thorough to inform the decisionmaker and the public of potential impacts of the Proposed Action.

Comment #6: OSMRE fails to take a hard look at impacts to Greater sage-grouse. In addition to 

global impacts to carbon emissions, the Caballo West expansion would negatively impact the local 

sage grouse population in Wyoming. The proposed expansion of the Caballo West mine is within 

General Habitat Management Area (“GHMA”) for sage grouse and within four miles of at least six 

“historical” sage-grouse leks, including one (the Lynde lek) confirmed active as recently as 2009.

The proposed mine plan includes no specific mitigation measures for greater sage-grouse other 

than the provisions applicable to General Habitat Management Areas (GHMAJ under the Wyoming 

ARMPA). Draft EA at 4-28. The 2019 Wyoming Sage-Grouse Plan amendments eliminate 

previously applicable noise standards for activities in GHMA. Wyoming 2019 Sage-Grouse Plan 

Amendments A-8 (Management Decision SSS 12). Therefore, implementation of the 2019 plan 

amendments will result in increased noise impacts to the Lynde lek and other potentially suitable 

sage-grouse habitat in the immediate vicinity of the mine expansion not previously analyzed in 

BLM’s EIS for its 2015 amendments to the Buffalo RMP and other Wyoming RMPs. OSMRE must 

assess the effects of mine-related noise on lek use on the Lynde and other adjacent leks, and 

resulting effects on the viability, connectivity, and prospects for recovery of the Thunder Basin 

core population.

OSMRE must further incorporate into the mine plan all applicable provisions of the Wyoming 

Sage-Grouse Resource Management Plan Amendments. These include, but are not limited to:

• Management Direction SSS 4 (work with Wyoming Game and Fish to incorporate 

additional mitigation under State regulations, policies, and programs);

• Management Direction SSS 9 (seasonal 2-mile buffer on sage-grouse leks outside of Priority

Habitat Management Areas (“PHMA”)

• Management Direction SSS 10 (seasonal limitations on operations within winter 

concentration areas; Draft EA does not identify whether winter concentration area are 

present); and

• Management Direction SSS 13 (develop adaptive managementstrategies).

OSMRE should also consult with Wyoming Game and Fish to determine whether, in light ofrecent 

lek attendance declines, Draft EA at 4-28, soft or hard triggers for the affected grouse population 

require additional management measures. If, based on this review, the area should be reclassified 

as a Priority Habitat Management Area, OSMRE must apply all applicable management measures 

for PHMA, including determination whether surface mining is or is notsuitable.

Response #6: The specific noise protocols for measurement and implementation noise are 

specific to PHMAs (Table A-1, MD SSS 12 of Appendix A). The Wyoming ARMPA classified the 

Caballo West tract as a GHMA regarding Greater sage-grouse, which eliminates the need for 

noise evaluation for the Proposed Action. While the Lynde lek has a Wyoming Game and Fish 

management status of occupied, it has not been active (annual status) since 2009. Based on the 

lack of use of the area by Greater sage-grouse that was discussed in the EA and the statement 

regarding a lack of concern included in the Wyoming Game and Fish comment letter dated January 
Appendix B

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 B-17

18, 2019 for review of the Proposed Action, there is little likelihood of reclassification of the area 

to a PHMA. The EA adequately evaluates the Proposed Action for suitability for mining as related 

to Greater sage- grouse. No changes made related to noise or habitat reclassification.

MD SSS 4: The Wyoming Game and Fish reviewed the proposed action and responded in a 

comment letter dated January 18, 2019 that they had no terrestrial wildlife concerns pertaining to 

the project. The comment letter did not include any recommendations for additional mitigation. 

No changes made.

MD SSS9: As indicated in Appendix A (Table A-1) of the 2019 Wyoming Sage-Grouse Plan 

amendments, the management goals, objectives, decisions related to MD SSS 9 are specific to the 

protection of Greater Sage-Grouse breeding, nesting, and early brood rearing habitat within 2 

miles of the perimeter of an occupied lek (or lek center if no perimeter is yet mapped) located 

outside PHMA. The are no leks within 2 miles of the proposed disturbance. No changes made.

MD SSS 10: The EA provides on page 4-17 that no winter concentration or connectivity areas are 

near the tract so there would be no seasonal limitations on operations. No changes made.

MD SSS 13: As stated in Appendix A (MD SSS 13 in Table A-1) and Appendix C (COT Objective

6) of the 2019 Wyoming Sage-Grouse Plan amendments, the requirement for development for 

adaptive management strategies are specific to an EIS so the requirement is not applicable to this 

EA. Based on thorough analysis described in Section 4.10.2 of the EA and coordination with the 

WY Game and Fish, OSMRE determined that impacts to greater sage grouse resulting from the 

proposed project would be minor to moderate and short-term, and adaptive management 

practices would not be necessary. No changes made.

Commenter: Peabody Energy

Comment #1: The Introduction to the FONSI appears to contain some information from 

previous documents published by the Office of Surface Mining Reclamation and Enforcement 

(OSMRE) that does not pertain to the Caballo Mine or the Caballo West lease tract. Reference to 

"surface mining permit No. PT0214", for example, is specific to a neighboring mine operated by a 

different company. OSMRE may wish to check other references throughout the FONSI for 

accuracy.

Response #1: The text in Section A of the FONSI has been revised to correct the permit 

number.

Comment #2 In Section C of the FONSI, the first sentence refers to a" ... currently approved 

federal mining plan modification related to WYW172657 ... ". This implies that a federal mining 

plan has been previously approved for the subject lease. OSMRE may wish to consider rewording 

this sentence for clarification.

Response #2: The text in Section C of the FONSI has been revised for clarification.

Comment #3 Table 2-2 located on page 2-6 shows outdated information concerning backfilling 

acreage and total disturbed acreage. Current information shows that 60% of the total disturbed

acreage at the Caballo Mine is in some stage of reclamation. Of the remaining acreage, 17% is 

long- term disturbance and 23% is active mining.

Response #3: Table 2-2 was based on information included in PCM’s 2018 Annual Report, which

was the most current report available at the time of publication.
Appendix B

B-18 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

Comment #4: It should be noted for the readers that PM10 sampler BA-1, included on Table 3-

1, is a Belle Ayr Mine sampler. This sampler happens to lie within the lease tract area and 

therefore captures air quality data relative to the area of interest.

Response #4: The text in Section 3.4.1.1 of the EA has been revised for clarification.

References

Anthoff, D. and Tol, R.S.J. 2013. “The uncertainty about the social cost of carbon: a decomposition 

analysis using FUND.” Climatic Change, 117: 515-530.

Hope, Chris. 2013. “Critical issues for the calculation of the social cost of CO2: why the estimates 

from PAGE09 are higher than those from PAGE2002.” Climatic Change, 117: 531-543.

Nordhaus, William D. 2017. “Revisiting the social cost of carbon.” Proceedings of the National Academy 

of Sciences of the United States, 114 (7): 1518-1523.

Pindyck, Robert. 2013. “Climate change policy: What do the models tell us?” Journal of Economic 

Literature, 51(3), 860-872.

Waldhoff, S., Anthoff, D., Rose, S., & Tol, R. S. J. (2011). The marginal damage costs of different 

greenhouse gases: An application of FUND (Economics Discussion Paper No. 2011–43). Kiel: Kiel 

Institute for the World Economy. 

Waldhoff, S., D. Anthoff, S. Rose, and R.S.J. Tol. 2014. The Marginal Damage Costs of Different 

Greenhouse Gases: An Application of FUND. The Open-Access, Open Assessment E-Journal 8(31): 1-33. 

http://dx.doi.org/10.5018/economics-ejournal.ja.2014- 31.
Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

APPENDIX C

GREENHOUSE GAS EMISSIONS CALCULATIONS

PM10, PM2.5, SO2, NOX, Hg, CO, and CO2 CONTRIBUTIONS FROM COAL COMBUSTION 

CALCULATIONS

(Completed by WWC Engineering)

Appendix C

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 C-1

GHG Calculations Assumptions 

Direct Emissions Variables

Source: SGAC Calculations (BLM 2009)

Indirect Emissions Assumptions

Train: 130 Cars/Train, 1/2 aluminum rotary, 1/2 aluminum bottom dump

23 Tons/car empty - 1/2 are 21 tons and 1/2 are 25 tons (BNSF 2017) 

119 Tons of Coal/Car (BNSF 2017)

15,470 Tons of Coal/Train (calculated)

200 Tons/locomotive – four per train (4Rail 2017) 

3,790 Weight of empty 130-car train (tons) (calculated) 

19,260 Weight of loaded coal train (tons) (calculated)

Transportation Emissions Variables

Emission Rate (kg/gal) CO2e Conversion Rate Kg CO2e/Gal Diesel Kg CO2e/Mile/Ton

CO2 10.21 1 10.21 0.023417431

CH4 0.0000112 25 0.00028 0.000001

N2O 0.0000224 298 0.0066752 0.000015

Total 10.2169552 0.0234

Source: Conversion Rate – EPA 2017a 

Emission Rate – EPA 2014

Transportation Variables

Miles/gal/1 Ton1 Miles Kg 

CO2e/Mile/Ton2 Tons Kg CO2e

/Mile Kg CO2e/Trip Metric Tons CO2e/Trip

Loaded 436 1,131 0.0234 19,260.0 451.3

(Calculated)

510,631.3

(Calculated)

510.6

(Calculated)

Empty 436 1,131 0.0234 3,790.0 88.8

(Calculated)

100,482.5

(Calculated)

100.5

(Calculated) 1 FactCheck 2008 2 EPA 2014

Caballo Mine Production, 2013-2017

2013 2014 2015 2016 2017 Average

Production (Tons) 8,979,111 7,990,986 11,402,155 11,221,557 11,125,949 10,143,952

Source: WDWS (2013-2017)

Source CO2e/Mt Coal Mined

FUEL subtotal 3,266.9

ELECTRICITY subtotal 2,670.1

PROCESS subtotal 1,147.7
Appendix C

C-2 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

Estimated 2013 Caballo Mine Equivalent CO2e (in metric tons)

Source Coal (Mt) Ave. Known Ratio (tons CO2e/Mt 

coal) Tons CO2e

Direct

Fuel 8.98 3266.9 29,334

Electricity 2670.1 23,975

Mining Process 1147.7 10,305

Total Direct 63,614

Indirect

Rail Transport

2013 Coal Production 8,979,111

2013 Coal Shipped by Rail 8,979,111

Tons Coal/Train 15,470

Empty Train Tons 3,790

Loaded Train Tons 19,260

# Loaded Trains/year 580

# Empty Trains/year 580

Average Rail Miles to Power Plant 1,052

Kg CO2e/Mi/Loaded Train 451.33

Kg CO2e/Mi/Empty Train 88.81

Kg CO2e/year Empty 54,229,172.3

Kg CO2e/year Loaded 275,581,493.3

Kg CO2e/year Total 329,810,665.6

Rail Transport (Metric Tons CO2e/year) 329,811

Power Plant Combustion (Metric Tons CO2e/year) 15,040,011

Total Indirect CO2e 15,369,822

Total Direct + Indirect CO2e 15,433,436

100% Coal shipped to U.S. power plants
Appendix C

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 C-3

Estimated 2014 Caballo Mine Equivalent CO2e (in metric tons)

Source Coal (Mt) Ave. Known Ratio (tons CO2e/Mt 

coal) Tons CO2e

Direct

Fuel 7.99 3266.9 26,106

Electricity 2670.1 21,337

Mining Process 1147.7 9,171

Total Direct 56,614

Indirect

Rail Transport

2014 Coal Production 7,990,986

2014 Coal Shipped by Rail 7,990,986

Tons Coal/Train 15,470

Empty Train Tons 3,790

Loaded Train Tons 19,260

# Loaded Trains/year 517

# Empty Trains/year 517

Average Rail Miles to Power Plant 1,098

Kg CO2e/Mi/Loaded Train 451.33

Kg CO2e/Mi/Empty Train 88.81

Kg CO2e/year Empty 50,371,699.7

Kg CO2e/year Loaded 255,978,611.4

Kg CO2e/year Total 306,350,311.1

Rail Transport (Metric Tons CO2e/year) 306,350

Power Plant Combustion (Metric Tons CO2e/year) 13,384,902

Total Indirect CO2e 13,691,252

Total Direct + Indirect CO2e 13,747,866

100% Coal shipped to U.S. power plants
Appendix C

C-4 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

Estimated 2015 Caballo Mine Equivalent CO2e (in metric tons)

Source Coal (Mt) Ave. Known Ratio (tons CO2e/Mt 

coal) Tons CO2e

Direct

Fuel 11.40 3266.9 37,250

Electricity 2670.1 30,445

Mining Process 1147.7 13,086

Total Direct 80,781

Indirect

Rail Transport

2015 Coal Production 11,402,155

2015 Coal Shipped by Rail 11,402,155

Tons Coal/Train 15,470

Empty Train Tons 3,790

Loaded Train Tons 19,260

# Loaded Trains/year 737

# Empty Trains/year 737

Average Rail Miles to Power Plant 1,009

Kg CO2e/Mi/Loaded Train 451.33

Kg CO2e/Mi/Empty Train 88.81

Kg CO2e/year Empty 66,048,354.6

Kg CO2e/year Loaded 335,644,144.9

Kg CO2e/year Total 401,692,499.5

Rail Transport (Metric Tons CO2e/year) 401,692.5

Power Plant Combustion (Metric Tons CO2e/year) 19,098,610

Total Indirect CO2e 19,500,302

Total Direct + Indirect CO2e 19,581,083

100% Coal shipped to U.S. power plants
Appendix C

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 C-5

Estimated 2016 Caballo Mine Equivalent CO2e (in metric tons)

Source Coal (Mt) Ave. Known Ratio (tons CO2e/Mt 

coal) Tons CO2e

Direct

Fuel 11.22 3266.9 36,660

Electricity 2670.1 29,963

Mining Process 1147.7 12,879

Total Direct 79,501

Indirect

Rail Transport

2016 Coal Production 11,221,557

2016 Coal Shipped by Rail 11,221,557

Tons Coal/Train 15,470

Empty Train Tons 3,790

Loaded Train Tons 19,260

# Loaded Trains/year 725

# Empty Trains/year 725

Average Rail Miles to Power Plant 1,238

Kg CO2e/Mi/Loaded Train 451.33

Kg CO2e/Mi/Empty Train 88.81

Kg CO2e/year Empty 79,754,952.5

Kg CO2e/year Loaded 405,298,254.5

Kg CO2e/year Total 485,053,207.0

Rail Transport (Metric Tons CO2e/year) 485,053

Power Plant Combustion (Metric Tons CO2e/year) 18,796,108

Total Indirect CO2e 19,281,161

Total Direct + Indirect CO2e 19,360,663

100% Coal shipped to U.S. power plants
Appendix C

C-6 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

Estimated 2017 Caballo Mine Equivalent CO2e (in metric tons)

Source Coal (Mt) Ave. Known Ratio (tons CO2e/Mt 

coal) Tons CO2e

Direct

Fuel 11.13 3266.9 36,347

Electricity 2670.1 29,707

Mining Process 1147.7 12,769

Total Direct 78,824

Indirect

Rail Transport

2017 Coal Production 11,125,949

2017 Coal Shipped by Rail 11,125,949

Tons Coal/Train 15,470

Empty Train Tons 3,790

Loaded Train Tons 19,260

# Loaded Trains/year 719

# Empty Trains/year 719

Average Rail Miles to Power Plant 1,260

Kg CO2e/Mi/Loaded Train 451.33

Kg CO2e/Mi/Empty Train 88.81

Kg CO2e/year Empty 80,480,655.7

Kg CO2e/year Loaded 408,986,128.9

Kg CO2e/year Total 489,466,784.6

Rail Transport (Metric Tons CO2e/year) 489,467

Power Plant Combustion (Metric Tons CO2e/year) 18,635,965

Total Indirect CO2e 19,125,431

Total Direct + Indirect CO2e 19,204,255

100% Coal shipped to U.S. power plants
Appendix C

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 C-7

Summary of Estimated Caballo Mine 2013-17 CO2e Emissions

CO2e Source 2013 2014 2015 2016 2017 Avg. % Of Total 

Emissions

Direct Emissions

Fuel 29,334 26,106 37,250 36,660 36,347 33,139

Electricity 23,975 21,337 30,445 29,963 29,707 27,085

Mining Process 10,305 9,171 13,086 12,879 12,769 11,642

Total Direct Emissions 63,614 56,614 80,781 79,501 78,824 71,867 0.4%

Indirect Emissions

Rail Transport 329,811 306,350 401,692 485,053 489,467 402,475 2.3%

Power Plant Combustion 

(CO2e) 15,040,011 13,384,902 19,098,610 18,796,108 18,635,965 16,991,119 97.3%

Total Indirect Emissions 15,369,822 13,691,252 19,500,302 19,281,161 19,125,431 17,393,594 99.6%

Total Emissions 15,433,436 13,747,866 19,581,083 19,360,663 19,204,255 17,465,460 100%
Appendix C

C-8 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

Estimated 2018-2051 Caballo Mine Equivalent CO2e (in metric tons)

Source Coal (Mt) Ave. Known Ratio (tons/Mt coal) Tons

Direct

Fuel 13.5 3266.9 44,103

Electricity 2670.1 36,046

Mining Process 1147.7 15,494

Total Direct 95,643

Indirect

Rail Transport

2017 Coal Production 13,500,000

2017 Coal Shipped by Rail 13,500,000

Tons Coal/Train 15,470

Empty Train Tons 3,790

Loaded Train Tons 19,260

# Loaded Trains/year 873

# Empty Trains/year 873

Average Rail Miles to Power Plant 1,031

Kg CO2e/Mi/Loaded Train 451.33

Kg CO2e/Mi/Empty Train 88.81

Kg CO2e/year Empty 87,655,722

Kg CO2e/year Loaded 445,448,337

Kg CO2e/year Total 533,104,059

Rail Transport (Metric Tons CO2e/year) 533,104

Power Plant Combustion (Metric Tons CO2e/year) 22,615,500

Total Indirect 23,145,604

Total Direct + Indirect CO2e 23,241,248

100% Coal shipped to U.S. power plants
Appendix C

Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 C-9

Summary of Estimated Caballo Mine 2018-2051 CO2e Emissions

CO2e Source 2018-2051 % Of Total 

Emissions

Direct Emissions

Fuel 44,103

Electricity 36,046

Mining Process 15,494

Total Direct Emissions 95,643 0.4%

Indirect Emissions

Rail Transport 533,104 2.3%

Power Plant Combustion 

(CO2e) 22,612,500 97.3%

Total Indirect Emissions 23,145,604 99.6%

Total Emissions 23,241,248 100%
Appendix C

C-10 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

Parameters Used to Calculate Combustion Emissions

Btu per short ton 16,890,000 https://pubs.usgs.gov/pp/p1625a/Chapters/PG.pdf

tons per kg 0.00110231 Conversion

tons to generate 1KW-h 0.000618709 https://www.eia.gov/tools/faqs/faq.cfm?id=667&t=2

tons to generate 1 MW-h 0.618709295 Calculated

PM10 Emissions per Btu (kg/MW-h)

PM10 Emissions per Btu (ton/MW-h)

0.39

0.000429901

http://www3.cec.org/islandora/en/item/10236-north-american-power-plant-air-emissions

Calculated

PM2.5 Emissions per Btu (kg/MW-h)

PM2.5 Emissions per Btu (ton/MW-h)

0.305

0.00013112

http://www3.cec.org/islandora/en/item/10236-north-american-power-plant-air-emissions

Calculated

SO2 Emissions (kg/MW-h) 17.5 AP-42 Table 1.1-3, with S (sulfur content %) = 0.5 from USGS 1625-A cited above

NOx Emissions (kg/MW-h) 7.2 AP-42 Table 1.1-3, pulverized coal, dry bottom, tangentially fired, sub-bituminous, NSPS

Hg Emissions per Btu (kg/MW-h) 0.000083 AP-42 Table 1.1-18

CO Emissions (lb) per ton 0.50000000 AP-42 Table 1.1-3

Combustion Emissions Values

Years 2013 2014 2015 2016 2017 Avg 2018-2051

Tons of Coal Mined (From CCC) 8,979,111 7,990,986 11,402,155 11,221,557 11,125,949 10,143,952 13,500,000

mw-h from coal mined 14,512,649 12,915,575 18,428,938 18,137,043 17,982,515 16,395,344 21,819,617

PM10 Emissions (Tons) 6,239.0 5,552.4 7,922.6 7,797.1 7,730.7 7,048 9,380

PM 2.5 Emissions (Tons) 1,902.9 1,693.5 2,416.4 2,378.1 2,357.9 2,150 2,861

SO2 Emissions (Tons) 78,567.2 69,921.1 99,768.9 98,188.6 97,352.1 88,760 118,125

NOx Emissions (Tons) 32,324.8 28,767.5 41,047.8 40,397.6 40,053.4 36,518 48,600

Hg Emissions (Tons) 0.4 0.3 0.5 0.5 0.5 0.4 0.6

CO Emissions (Tons) 2,244.8 1,997.7 2,850.5 2,805.4 2,781.5 2,536 3,375
Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

APPENDIX D

REVENUE CALCULATIONS

(Completed by WWC Engineering)
Appendix C

D-2 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

Appendix D

Estimated 2018 Fiscal Revenue from 2017 Coal Production in Campbell Co. (Million U.S. 

Dollars)

Revenue Source Total Collected Federal Revenue State Revenue

Federal Mineral Royalties 477.5 238.9 238.9

Abandoned Mine Lands Fund 85.6 57.6 28.0

Severance Tax 196.1 196.1

Bonus Bid Annual Revenues 0.0 0.0 0.0

Ad Valorem Tax 161.2 161.2

Black Lung 161.3 161.3

Sales and Use Tax 25.3 25.3

Totals 1,106.9 457.6 649.3

$/Ton $2.05

Total Future Revenues from Caballo Mine (No Action Alternative) (Million U.S. Dollars)

Revenue Source Total Collected Federal Revenue State Revenue

Federal Mineral Royalties 506.4 253.2 253.2

Abandoned Mine Lands Fund 90.7 45.4 45.4

Severance Tax 211.8 211.8

Bonus Bid Annual Revenues 0.0 0.0 0.0

Ad Valorem Tax 170.9 170.9

Black Lung 13.7 13.7

Sales and Use Tax 25.9 25.9

Totals 1,019.4 312.2 707.2

$/Ton $2.18

Future Revenues added by the Caballo West Tract only (Million U.S. Dollars)

Revenue Source Total Collected Federal Revenue State Revenue

Federal Mineral Royalties 187.2 93.6 93.6

Abandoned Mine Lands Fund 33.5 16.8 16.8

Severance Tax 74.2 74.2

Bonus Bid Annual Revenues 0.0 0.0 0.0

Ad Valorem Tax 63.2 63.2

Black Lung 5.0 5.0

Sales and Use Tax 9.6 9.6

Totals 372.7 115.4 257.3

$/Ton $2.15

Total Future Revenues from Caballo Mine (existing mine plus Caballo West tract) (Million

U.S. Dollars)

Revenue Source Total Collected Federal Revenue State Revenue

Federal Mineral Royalties 693.6 346.8 346.8

Abandoned Mine Lands Fund 124.3 62.1 62.1

Severance Tax 286.0 286.0

Bonus Bid Annual Revenues 0.0 0.0 0.0

Ad Valorem Tax 234.1 234.1

Black Lung 18.7 18.7

Sales and Use Tax 35.4 35.4

Totals 1,392.1 427.7 964.5

$/Ton $2.17
Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 D-1

Difference Between the Caballo Mine No Action Alternative and the Proposed Action 

(Million U.S. Dollars)

Revenue Source Total Collected Federal Revenue State Revenue

Federal Mineral Royalties 187.2 93.6 93.6

Abandoned Mine Lands Fund 33.5 16.8 16.8

Severance Tax 74.2 74.2

Bonus Bid Annual Revenues 0.0 0.0 0.0

Ad Valorem Tax 63.2 63.2

Black Lung 5.0 5.0

Sales and Use Tax 9.6 9.6

Totals 372.7 115.4 257.3

Estimated 2022 Campbell Co. Fiscal Revenue (Million U.S. Dollars)

Revenue Source Total Collected Federal Revenue State Revenue

Federal Mineral Royalties 438.172 219.1 219.1

Abandoned Mine Lands Fund 78.520 39.3 39.3

Severance Tax 173.670 173.7

Bonus Bid Annual Revenues 0.000 0.0 0.0

Ad Valorem Tax 147.892 147.9

Black Lung 11.819 11.8

Sales and Use Tax 22.376 22.4

Totals 872.4 270.2 602.3

$/Ton $2.15

All revenues were calculated using variables presented below
Appendix D

D-4 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

Appendix D

Bonus Bid Payments, 2008-2017

Bonus Bids Lease-Month Tons Total Bid $/Ton 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017

WYW155132 Eagle Butte 

West - May 255,000,000 $180,540,000.00 $0.71 $36,108,000.00 $36,108,000.00 $36,108,000.00 $36,108,000.00 $36,108,000.00

$144,432,000.00 $108,324,000.00 $72,216,000.00 $36,108,000.00 $0.00

WYW174407 South Maysdorf

- August 288,100,000 $250,800,000.00 $0.87 $50,160,000.00 $50,160,000.00 $50,160,000.00 $50,160,000.00 $50,160,000.00

$200,640,000.00 $150,480,000.00 $100,320,000.00 $50,160,000.00 $0.00

WYW154432 North Maysdorf

- August 54,657,000 $48,098,424.00 $0.88 $9,619,684.80 $9,619,684.80 $9,619,684.80 $9,619,684.80 $9,619,684.80

$38,478,739.20 $28,859,054.40 $19,239,369.60 $9,619,684.80 $0.00

WYW177903 West Antelope 

South 56,356,000 $49,311,500.00 $0.88 $9,862,300.00 $9,862,300.00 $9,862,300.00

$39,449,200.00 $29,586,900.00 $0.00

WYW163340 West Antelope 

North 350,263,000 $297,723,228.00 $0.85 $59,544,645.60 $59,544,645.60 $59,544,645.60 $59,544,645.60 $59,544,645.60

$238,178,582.40 $178,633,936.80 $119,089,291.20 $59,544,645.60 $0.00

WYW161248 Belle Ayr North 221,734,800 $210,648,060.00 $0.95 $42,129,612.00 $42,129,612.00 $42,129,612.00 $42,129,612.00 $42,129,612.00

$168,518,448.00 $126,388,836.00 $84,259,224.00 $42,129,612.00 $0.00

WYW172657 Caballo West 130,196,000 $143,417,403.80 $1.10 $28,683,480.76 $28,683,480.76 $28,683,480.76 $28,683,480.76 $28,683,480.76

$114,733,923.04 $86,050,442.28 $57,366,961.52 $28,683,480.76 $0.00

WYW174596 South Hilight 222,676,000 $300,001,011.66 $1.35 $60,000,202.33 $60,000,202.33 $60,000,202.33 $60,000,202.33 $60,000,202.33

$240,000,809.33 $180,000,607.00 $120,000,404.66 $60,000,202.33 $0.00

WYW176095 South 

Porcupine LBA 401,830,508 $446,031,864.00 $1.11 $89,206,372.80 $89,206,372.80 $89,206,372.80 $89,206,372.80 $89,206,372.80

$356,825,491.20 $267,619,118.40 $178,412,745.60 $89,206,372.80 $0.00

WYW173408 North 

Porcupine LBA 721,154,828 $793,270,311.00 $1.10 $158,654,062.20 $158,654,062.20 $158,654,062.20 $158,654,062.20 $158,654,062.20

$634,616,248.80 $475,962,186.60 $317,308,124.40 $158,654,062.20 $0.00

Average $0.98 $86,268,000.00 $95,887,684.80 $95,887,684.80 $236,107,723.16 $543,968,360.49 $457,700,360.49 $438,218,375.69 $438,218,375.69 $307,860,637.33 $0.00

Source: BLM 2017. Bids are paid off in four equal annual payments, after the initial 1/5 amount payment attached to the bid.

Revenue Variables

Coal Surface # Units of Taxable 

Valuation

Taxable 

Valuation

Taxable Valuation 

Per Unit

Average Tax 

Levy (Mills)

Estimated Ad 

Valorem Tax Levied

Average Tax 

Per Unit

Sev. Tax 

Rate %

Estimated Severance 

Tax Collectible

Average Sev. 

Tax Per Unit

2015 Wyoming 392,418,629 $3,894,432,347 9.92 $0.059925 $233,373,858 0.5947 0.07 $272,610,264 $0.6947

2015 Campbell Co. 358,196,669 $3,348,921,099 9.35 $0.059592 $199,568,906 0.5571 0.07 $234,424,477 $0.6545

2016 Wyoming 372,577,808 $3,646,317,231 9.79 $0.059910 $218,450,865 0.5863 0.07 $255,242,206 $0.6851

2016 Campbell Co. 340,675,046 $3,149,810,399 9.25 $0.059554 $187,583,809 0.5506 0.07 $220,486,728 $0.6472

2017 Wyoming 314,755,317 $2,995,345,054 9.52 62.462 $187,095,243 0.5944 0.07 209,674,154 $0.6661

2017 Campbell Co. 292,994,954 $2,592,159,599 8.85 59.610 $154,518,634 0.5274 0.07 181,451,172 $0.6193

Source: WDOR 2015 and 2016a
Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

Revenue Calculations Variables

Coal Production (tons)1

Campbell Wyoming

2017 Tons Produced 305,612,350 316,603,867

2022 Tons Produced (Estimated) 280,430,000 290,000,000

From Campbell Co. 96.53%

Caballo West Tract2 (tons mineable) (tons recoverable)

No Action Alternative 363,900,000 324,100,000

Added by Proposed Action 130,200,000 119,800,000

Average 2017 Sales Price ($/ton)

2017 PRB Subbituminous Coal $12.522 $12.503

2017 Price without BLT4 $12.48 $12.46

Federal Royalties

WY share of FR = 0.5 x FR

Federal Royalties3 $477,519,296.88

Wyoming Share $238,759,648.44

Abandoned Mine Lands Funds5

Campbell AML Total $85,571,458.00

WY Share6 $28,000,000.00

Severance Taxes7

Campbell ST Rate/Ton $0.6193

2017 Severance Taxes8 $196,072,123.16

Lease Bonus Bids (2017 Payments)

2017+ $0.00

Total 2017+ Bonus Bid Payments $0.00

WY share $0.00

Campbell Ad Valorem Taxes7

AVT Rate/ton $0.53

AVT (Total) $161,172,750.99

Black Lung

2017 BLT Rate/Ton8 $0.528

2017 BLT Collected9 $161,260,279.09

Future BLT Rate/Ton10 $0.527

Future BLT Collected $147,736,111.11

2017 Campbell Co. Employment (mining)11

Buckskin 202

Belle Ayr 244

Eagle Butte 271

Cordero Rojo 366

Antelope 526

Caballo 160

NARM 1,364

Rawhide 113

Black Thunder 1,220

Coal Creek 155

Dry Fork 79

Wyodak 63

Total 4,763

Federal Income Tax12

Head of Household income info:

10% on first $12,750

15% on next (up to $48,600)

Rate10 13.6%

Tax/employee $6,197.23

Fed Tax $29,517,409.88

Fiscal Year 2017 Sales and Use Tax13

Coal Mining $25,262,023.00

$/ton $0.08 1 WDOR 2017

2 CCC 2018a

3 Calculated - Tons produced x 2017 sales price per ton x 12.5% 4 Black lung tax removed since it is included in the sale price

5 Calculated - AML = $0.28 per ton produced - through 2021, WY share = 0.5 x AML (Max 28,000,000/yr as of September 2013), Price from 

CREG 2018

6 Calculated - Wyoming’s portion of 2017 + AML Funds (Max out at $75,000,000) 7 WDOR 2017, recalculated using Campbell Co. numbers only

8 Calculated - Maximum per ton rate is $0.55 9 IRS 2018
D-4 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

Appendix D

10 Calculated - Rate x 2022 Estimated Production 11 WDWS 2017 12 WDOE 2015 (This is the most current doc as of December 2018) 13 WDOR 2018

REFERENCES

Caballo Coal Company (CCC), 2018a, Personal communication between Kim Cox, Caballo Mine, and Beth Kelly, WWC Engineering, 

November 30, 2018. Electronic copy only, available on request from OSMRE.

Internal Revenue Service (IRS), 2018, Coal Excise Tax Audit Technique Guide (ATG). Available on the internet as of December 2018: 

https://www.irs.gov/pub/irs-mssp/coal.pdf

Wyoming Department of Administration & Information, Consensus Revenue Estimating Group (CREG), 2018, Wyoming State Government

Revenue Forecast Fiscal Year 2019 – Fiscal Year 2024. Available on the internet as of January 2019: 

http://eadiv.state.wy.us/creg/GreenCREG_Oct18.pdf

Wyoming Department of Employment (WDOE), 2015, Wage Records in Wyoming: Employment and Earnings by Age and Gender with Place of 

Work in Campbell County, 2000-2015. Available on the internet as of December 2018: 

https://doe.state.wy.us/LMI/earnings_tables/2016/County/Campbell_2000-2015.pdf

Wyoming Department of Revenue (WDOR), 2017, 2017 Annual Report. Available on the internet as of January 2019: 

https://sites.google.com/a/wyo.gov/wy-dor/2017AnnualReport.pdf?attredirects=0

Wyoming Department of Revenue (WDOR), 2018, Total Distribution by Major Class and By County Reporting Date Range: 07/2017 –

06/2018. Available on the internet as of December 2018: https://0ebaeb71-a-84cef9ff-s-sites.googlegroups.com/a/wyo.gov/wydor/FY2018MajorBusinessClassbyCountySUMMARY.pdf?attachauth=ANoY7cqdFsqwnvEjV3RL7kqs5q1SUoga7iqY504phcToIpogIXFt0me3ZDnvDxsJBUU7YPleBupV7Ay2WWGxQr9fFj3DHmncGk9-WzSdr1UncPWkpfIH0Q3lJhLVTrKn5pkO5-

sr7N74YF8vQCFKGTHRh7hKSjJ7GeNlDwRKi_mTF_ygjxmhLZTUx_183XbS97YWv_ZJFveIZsBsHVRqnpUZUzPwzwyL1glDJor98qOc6JHI
Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

APPENDIX E

CABALLO MINE SPECIAL STATUS SPECIES SUMMARY TABLES 

FOR FEDERAL LEASE MODIFICATION APPROVAL - WYW172657
D-4 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433

Appendix D

Appendix E

Vertebrate Species of Special Interest Associated with the Caballo Mine Project Area

Common Name Scientific Name Status Under 

the ESA

Protected Under 

the MBTA

Listed as a BLM 

Sensitive Species

Listed as a 

WYNDD SOC

WGFD SGCN Observed 

in the Area SGCN NNS Tier

Amphibian Great plains toad Anaxyrus cognatus Yes NSSU(U) II

Amphibian Northern leopard frog Lithobates pipiens NW Yes Yes Yes NSS4(Bc) II

Amphibian Plains spadefoot Spea bombifrons Yes Yes NSS4(Bc) II

Bird Western grebe Aechmophorus occidentalis Yes Yes NSSU(U) II Yes

Bird Western tiger salamander Ambystoma mavortium Yes NSS4(Bc) III

Bird Baird's sparrow Ammodramus bairdii NW Yes Yes Yes Yes NSS4(Bc) II Yes

Bird Grasshopper sparrow Ammodramus savannarum Yes Yes NSS4(Bc) II Yes

Bird Golden eagle Aquila chrysaetos Yes Yes NSS4(Bc) II Yes

Bird Great blue heron Ardea herodias Yes Yes NSS4(Bc) II Yes

Bird Short-eared owl Asio flammeus Yes Yes Yes NSS4(Bc) II Yes

Bird Burrowing owl Athene cunicularia Yes Yes Yes Yes NSSU(U) I Yes

Bird Lesser scaup Aythya affinis Yes

Bird Redhead Aythya americana Yes Yes

Bird Canvasback Aythya valisineria Yes Yes

Bird Upland sandpiper Bartramia longicauda Yes Yes NSSU(U) II Yes

Bird Ferruginous hawk Buteo regalis NW Yes Yes Yes Yes NSS4(Cb) II Yes

Bird Swainson's hawk Buteo swainsoni Yes Yes NSSU(U) II Yes

Bird Lark bunting Calamospiza melanocorys Yes Yes

Bird Chestnut-collared longspur Calcarius ornatus Yes Yes Yes NSS4(Bc) II Yes

Bird Greater sage-grouse Centrocercus urophasianus NW Yes Yes Yes NSS4(Bc) II Yes

Bird Mountain plover Charadrius montanus NW Yes Yes Yes Yes NSSU(U) I Yes

Bird Yellow-billed cuckoo Coccyzus americanus Yes Yes Yes Yes NSSU(U) II

Bird Bobolink Dolichonyx oryzivorus Yes Yes Yes NSS4(Bc) II

Bird Willow flycatcher Empidonax traillii Yes Yes NSS3(Bb) III

Bird Merlin Falco columbarius Yes Yes NSSU(U) III

Bird American kestrel Falco sparverius Yes Yes NSS4(Bc) III Yes

Bird MacGillivray's warbler Geothlypis tolmiei Yes Yes NSS4(Bc) II

Bird Common yellowthroat Geothlypis trichas Yes Yes NSS4(Bc) III
Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433 E-1

Appendix E

Common Name Scientific Name Status Under 

the ESA

Protected Under 

the MBTA

Listed as a BLM 

Sensitive Species

Listed as a 

WYNDD SOC

WGFD SGCN Observed 

in the Area SGCN NNS Tier

Bird Bald eagle Haliaeetus leucocephalus DM Yes Yes Yes Yes NSS3(Bb) II Yes

Bird Loggerhead shrike Lanius ludovicianus Yes Yes Yes Yes NSS4(Bc) II Yes

Bird Red-headed woodpecker Melanerpes 

erythrocephalus Yes Yes NSS4(Bc) II Yes

Bird Long-billed curlew Numenius americanus Yes Yes Yes Yes NSS3(Bb) II Yes

Bird Sage thrasher Oreoscoptes montanus Yes Yes Yes NSS4(Bc) II Yes

Bird White-faced ibis Plegadis chihi Yes Yes Yes Yes NSS3(Bb) II Yes

Bird Virginia rail Rallus limicola Yes Yes NSSU(U) III

Bird Mccown's longspur Rhynchophanes mccownii Yes Yes Yes NSS4(Bc) II Yes

Bird Dickcissel Spiza americana Yes Yes NSSU(U) II

Bird Brewer's sparrow Spizella breweri Yes Yes Yes NSS4(Bc) II Yes

Mammal Black-tailed prairie dog Cynomys ludovicianus NW Yes Yes Yes NSS4(Cb) II Yes

Mammal Sagebrush vole Lemmiscus curtatus Yes NSS4(Cb) II

Mammal Western small-footed myotis Myotis ciliolabrum Yes NSS4(Cb) II

Mammal Little brown myotis Myotis lucifugus UR Yes NSS3(Bb) II

Mammal Olive-backed Pocket Mouse Perognathus fasciatus Yes NSS4(Cb) III

Mammal Plains harvest mouse Reithrodontomys montanus Yes NSS3(Bb) II

Reptile Eastern spiny softshell Apalone spinifera spinifera Yes NSS2(Ba) II

Reptile Western painted turtle Chrysemys picta bellii Yes NSS4(Bc) III

Reptile Prairie rattlesnake Crotalus viridis Yes NSS4(Bc) III Yes

Reptile Plains hog-nosed snake Heterodon nasicus Yes NSSU(U) II

Reptile Western milksnake Lampropeltis gentilis Yes NSS3(Bb) II

Reptile Plains gartersnake Thamnophis radix Yes NSSU(U) III

USWS: ESA – status as a T&E species: NW-not warranted for listing, DM-delisted, UR-petition for listing under review 

BCC – status as a USFWS bird of conservation concern

MBTA – protected under the Migratory Birds Treaty Act 

BLM: Listed as a sensitive species by BLM

WYNDD: Determined to be a species of concern

WGFD: SGCN-species of greatest conservation concern, which is based upon the Native Species Status (NSS) classification system 

Source: WYNDD 2019, NREX 2019

E-2 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433
Appendix E

Species of Special Interest Summary

Highest Priority

Moderate Priority

2 -

Tier 2 

I

3 -

Tier 34 

II

Lowest Priority - Tier III 10

NSSU 12 NSSU 12 Undetermined

NSS1 0 NSS1 0 Imperiled/Extreme

NSS2 1 NSS2(Ba) 1 Vulnerable/Extreme

NSS3 7 NSS3(Bb) 7 Vulnerable/Severe

NSS4 26 NSS4(Bc) 21 Vulnerable/Moderate

NSS4(Cb) 5 Stable/Severe

Amphibians 3

Birds 35

Mammals 6

Retiles 6

Total 50

33 MBTA

14 BLM Sensitive

17 WYNDD SOC

46 WGFD SGCN

46 NSS
APPENDIX F

CLIMATE CHANGE DISCUSSION

Historically, the coal mined in the PRB has been used as one of the sources of fuel to generate 

electricity in power plants located throughout the U.S. Coal-fired power plant emissions include 

CO2, which has been identified as a principal anthropogenic greenhouse gas. According to the 

EPA (2017) in 2016 (the most recent year of available CO2 data at this time):

1. CO2 emissions represent approximately 81.6 percent of the total 2016 U.S. 

greenhouse gas emissions.

2. Estimated CO2 emissions in the U.S. totaled 6,511.3 million metric tons in 2016, which 

was a 1.9 percent decrease from 2015.

3. Estimated CO2 emissions from fossil fuel combustion in the U.S. totaled 4,966.0 million 

metric tons in 2016.

4. Estimated CO2 emissions from the electric power sector totaled 1,809.3 million metric 

tons in 2014.

5. Estimated CO2 emissions from electric power generation from coal totaled 1,241.4

million metric tons, or about 19.1 percent of total U.S. energy-related CO2 emissions in

2016.

Approximately 98 percent of the 317.4 Mt coal mined in 2017 in Wyoming was used to generate 

electricity by coal-fired power plants in the U.S. (USEIA 2017). Coal production from Wyoming 

represented approximately 50 percent of the coal used for power generation in 2017, which 

means that, using a simple calculation (CO2 emissions from item number 5 above multiplied by 

50 percent), Wyoming surface coal mines were responsible for approximately 620.7 million 

metric tons of CO2 emissions from coal power generation in 2017. If a more accurate method 

of calculating CO2 emissions is used, based on the 1.686 metric tons of CO2 emissions per ton of 

coal combusted (EPA 2008), the emissions from burning 317.4 Mt of Wyoming coal were 

approximately 535.1 million metric tons in 2017. The Caballo Mine produced 11.1 Mt of coal in 

2017, which represents approximately 3.5 percent of the coal produced in Wyoming in 2017,or 

approximately 18.6 million metric tons of CO2 emissions from coal power generation in 2017.

As stated above, estimated CO2 emissions in the U.S. decreased 1.9 percent from 2015 to 2016 

(EPA 2017). Under the Proposed Action, CCC anticipates producing the coal included in the 

Caballo West tract at 13.5 Mtpy levels, using existing production and transportation facilities. 

This will extend the mine’s current GHG emissions by approximately 8.9 years and combustion 

of Caballo West tract federal coal in coal-fired power plants will also continue for approximately

8.9 additional years. Because CO2 emissions have been declining in recent years and because CO2 

from coal mined at the Caballo Mine will remain at or only slightly above current levels, climate 

impacts associated with direct/indirect emissions from the Caballo West tract from mining, 

transportation, and combustion will be moderate but short term.

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 EO 12866. That EO required federal agencies to assess the cost and the benefits of 

intended regulations as part of their regulatory impact analyses. The SCC protocol was also 

developed for use in cost-benefit analyses of proposed regulations that could impact cumulative 

global emissions (Shelanski and Obstfeld 2015).
Notably, 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 mt 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 figure arrived at based on the SCC calculation represents the 

value of damages avoided if, ultimately, there is no increase in carbon emissions.

EO 13783, issued March 28, 2017, directed that the IWG be disbanded and that technical 

documents issued by the IWG be withdrawn as no longer representative of federal policy. The 

2017 EO further directed that when monetizing the value of changes in greenhouse gas emissions 

resulting from regulations, agencies follow the guidance contained in OMB Circular A-4 of 

September 17, 2003. In all cases, a Federal agency should ensure that its consideration of the 

information and other factors relevant to its decision is consistent with applicable statutory or 

other authorities, including requirements for the use of cost-benefit analysis.

Based on emission estimates for coal combustion, SCC calculations can quickly rise to large 

values; however, specific threshold levels for the determination of significance can vary depending 

on numerous project factors. OSMRE has elected not to specifically quantify the SCC in its 

assessment of the Caballo Mine mining plan modification. NEPA does not require a cost-benefit 

analysis (40 C.F.R. § 1502.23) or the presentation of the SCC cost estimates quantitatively in all 

cases, and that analysis was not undertaken here. Without a complete monetary cost-benefit 

analysis, which will include the social benefits of energy production to society as a whole and 

other potential positive benefits, inclusion solely of a SCC analysis will be unbalanced, potentially 

inaccurate, and not useful.

Given the uncertainties associated with assigning a specific and accurate social cost of carbon 

resulting from 8.9 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 4.5.4.

Further, 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 

cost-benefit analysis, which is not required.

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 the agency did not undertake one here; and 4) because the full social benefits of coalfired energy production have not been monetized, quantifying only the costs of GHG emissions 

will provide information that is both potentially inaccurate and not useful.

F-2 Caballo West Tract Federal Mining Plan Modification EA for Permit No. 433