June 26, 2014

Marcelo Calle

Office of Surface Mining

Western Region

1999 Broadway, Suite 3320

Denver, Colorado 80202-5733

Harrilene Yazzi

Bureau of Indian Affairs

Navajo Regional Office 

301 West Hill Street 

P.O. Box 1060

Gallup, New Mexico 87305

Subject: EPA Comments on the Four Corners Power Plant and Navajo Mine Energy Project Draft 

Environmental Impact Statement, Navajo Nation, San Juan County, New Mexico

(CEQ # 20140097)

Dear Mr. Calle:

The U.S. Environmental Protection Agency (EPA) has reviewed the above-referenced document 

pursuant to the National Environmental Policy Act (NEPA), Council on Environmental Quality (CEQ) 

regulations (40 CFR Parts 1500-1508), and our NEPA review authority under Section 309 of the Clean 

Air Act. Our detailed comments are enclosed. 

The Draft Environmental Impact Statement (DEIS) assesses the impacts from the continued operation of 

the Four Corners Power Plant (FCPP), a coal-fired power plant with a generating capacity of up to 1,500 

megawatts (2 units), should the Bureau of Indian Affairs (BIA) approve Arizona Public Service 

Company’s proposed lease amendment and application for right-of-way renewals for operation through 

2041. The project also involves continued and extended surface coal mining at the Navajo Mine, should 

the Office of Surface Mining (OSM) renew the Navajo Mine’s existing Surface Mining Control and 

Reclamation Act (SMCRA) permit for 5 years and approve an application for a new SMCRA permit for 

the Pinabete Permit Area. Lastly, the project proposes right-of-way renewals by BIA for portions of 

four transmission lines.

EPA is a cooperating agency for the proposed project and provided comments on the Preliminary DEIS 

to the OSM and BIA on February 6, 2014. We found the DEIS to be largely responsive to our 

comments, and appreciate the changes made to the document to address them. Comments that were not 

fully addressed are reiterated in the attached Detailed Comments. Based on our review of the DEIS, we 

have rated the Preferred Alternative A as Environmental Concerns – Insufficient Information (EC-2) 

(see enclosed “Summary of Rating Definitions”). Our concerns regard the existing contamination of 

groundwater from coal combustion residue (CCR) disposal and the need for enforceable commitments 

regarding future CCR management, monitoring and remediation. We also have concerns regarding the 

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

REGION IX

75 Hawthorne Street

San Francisco, CA 94105
pp

y 

of-way renewals. Groundwater contamination from past disposal of CCR in Navajo Mine has also

occurred and we recommend monitoring of groundwater at the Navajo Mine to confirm the DEIS

conclusions that constituents of concern would be attenuated as groundwater travels towards the SanJuan River and the Chaco Rivers.

The DEIS concludes that that cumulative impacts to public health from both the FCPP and the Mine

would be minor. Emissions of some pollutants from the power plant will be reduced as a result ofEPA’ s Federal Implementation Plan -Best Available Retrofit Technology, and these reductions are

expected to have a positive impact on public health. Nevertheless, as disclosed in the DETS, health

outcomes for Navajo, in term of life expectancy and mortality rates, are worse than for the general

population in San Juan County, partly due to healthcare disparities. The cumulative health burden also

includes the impacts from in-home burning of coal that is provided by the Navajo Mine to local tribal

members free or at low-cost. This coal is often burned in improperly-vented stoves not designed to burncoal. Because many Navajo do not have access, or affordable access, to electricity, the provision of free

or cheap coal by the project directly contributes to the cumulative health burden from indoor exposure tocoal smoke. We recommend that the Final EIS incorporate the severely compromised existing public

health environment into its cumulative health impacts assessment and include commitments to

mitigation for the project’s contribution to the ongoing environmental justice and cumulative health

impacts. Please see the enclosed Detailed Comments for our recommendations regarding mitigation.

EPA appreciates the opportunity to review this DEIS and looks forward to continued coordination with

OSM, BIA, and the other cooperating agencies during the NEPA process. When the Final EIS isreleased for public review, please send one copy to the address above (mail code: CED-2). If you have

any questions, please contact me at (415) 972-3521, or contact Karen Vitulario, the lead reviewer for this

project, at 415-947-4178 or vitulano.karen@epa.gov.

Sinceely,

Kathleen Martyn Goforth, Manager

Environmental Review Section

Enclosure: Summary of EPA Rating Definitions

EPA’ s Detailed Comments

2
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cc: Ben Shelly, President, Navajo Nation

Stephen B. Etsitty, EPA Director, Navajo Nation

Herman Honanie, Chairman, Hopi Tribe

Gayl Honanie, Environmental Director, Hopi Tribe
SUMMARY OF EPA RATING DEFINITIONS

This rating system was developed as a means to summarize EPA's level of concern with a proposed action.

The ratings are a combination of alphabetical categories for evaluation of the environmental impacts of the

proposal and numerical categories for evaluation of the adequacy of the EIS.

ENVIRONMENTAL IMPACT OF THE ACTION

"LO" (Lack of Objections)

The EPA review has not identified any potential environmental impactsrequiring substantive changesto the

proposal. The review may have disclosed opportunities for application of mitigation measures that could be

accomplished with no more than minor changes to the proposal.

"EC" (Environmental Concerns)

The EPA review has identified environmental impacts that should be avoided in order to fully protect the

environment. Corrective measures may require changes to the preferred alternative or application of

mitigation measuresthat can reduce the environmental impact. EPA would like to work with the lead agency

to reduce these impacts.

"EO" (Environmental Objections)

The EPA review has identified significant environmental impacts that must be avoided in order to provide

adequate protection for the environment. Corrective measures may require substantial changes to the

preferred alternative or consideration of some other project alternative (including the no action alternative

or a new alternative). EPA intends to work with the lead agency to reduce these impacts.

"EU" (Environmentally Unsatisfactory)

The EPA review has identified adverse environmental impacts that are of sufficient magnitude that they are

unsatisfactory from the standpoint of public health or welfare or environmental quality. EPA intendsto work

with the lead agency to reduce these impacts. If the potentially unsatisfactory impacts are not corrected at

the final EIS stage, this proposal will be recommended for referral to the CEQ.

ADEQUACY OF THE IMPACT STATEMENT

Category 1" (Adequate)

EPA believes the draft EIS adequately sets forth the environmental impact(s) of the preferred alternative and

those of the alternatives reasonably available to the project or action. No further analysis or data collection is

necessary, but the reviewer may suggest the addition of clarifying language or information.

"Category 2" (Insufficient Information)

The draft EIS does not contain sufficient information for EPA to fully assess environmental impactsthatshould

be avoided in order to fully protect the environment, or the EPA reviewer has identified new reasonably

available alternatives that are within the spectrum of alternatives analysed in the draft EIS, which could reduce

the environmental impacts of the action. The identified additional information, data, analyses, or discussion

should be included in the final EIS.

"Category 3" (Inadequate)

EPA does not believe that the draft EIS adequately assesses potentially significant environmental impacts of the

action, or the EPA reviewer hasidentified new,reasonably available alternativesthat are outside ofthe spectrum

of alternatives analysed in the draft EIS, which should be analysed in order to reduce the potentially significant

environmental impacts. EPA believes that the identified additional information, data, analyses, or discussions

are of such a magnitude that they should have full public review at a draft stage. EPA does not believe that the

draft EIS is adequate for the purposes of the NEPA and/or Section 309 review, and thus should be formally

revised and made available for public comment in a supplemental or revised draft EIS. On the basis of the

potential significant impacts involved, this proposal could be a candidate for referral to the CEQ.

*From EPA Manual 1640, “Policy and Procedures for the Review of Federal Actions Impacting the Environment.”
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EPA DETAILED COMMENTS ON THE FOUR CORNERS POWER PLANT AND NAVAJO MINE ENERGY PROJECT 

DRAFT ENVIRONMENTAL IMPACT STATEMENT, NAVAJO NATION, NEW MEXICO, JUNE 26, 2014

Coal Combustion Residue (CCR) Management and Contamination

CCR management at the Four Corners Power Plant

EPA expects to finalize the CCR rule by the end of 2014, which will determine whether CCR is 

managed as hazardous waste under Subtitle C of the Resource Conservation and Recovery Act (RCRA),

as solid waste under Subtitle D of RCRA, or in some other manner. The DEIS indicates that CCR at the 

Four Corners Power Plant will be managed in accordance with this final EPA determination, and notes 

that, if EPA regulates CCR through Subtitle D, the authority to implement the regulations would be at 

the state level, which would not apply on tribal lands (p. 4.15-5). OSM proposes mitigation to address 

this regulatory gap, and we agree this is necessary. However, the DEIS identifies the mitigation 

measures as voluntary recommendations to Arizona Public Service, while also portraying them as if they 

were legal requirements. For example, on page 4.15-27, the DEIS states that both new and existing 

disposal units would be subject to groundwater monitoring requirements and, if certain hazardous 

constituents are detected at a level exceeding groundwater protection standards, the FCPP would have 

90 days to assess corrective measures and select a remedy that would protect human health and the 

environment. It is not clear what groundwater protection standards are being referenced. The DEIS 

notes that the Navajo Nation does not have groundwater quality standards (p. 4.15-18). Additionally,

the specific timeline and reference to corrective measures imply a rigorous enforcement program. The 

hazardous and solid waste mitigation measures on pages 4.15-31 through 4.15- 32 reference a “permit 

program” and “inspection requirements” and specify operating, design, groundwater monitoring, 

corrective action, and closure and post-closure requirements, but these “requirements” are simply 

recommendations to APS (“OSMRE recommends APS implement the measures below” – p. 4.15-31). 

Recommendations: The hazardous and solid waste mitigation measures presented on pages 4.15-

31 through 4.15- 32 should be enforceable conditions of the project since it is a possibility that 

coal ash could be regulated under Subtitle D and the standards would not have an enforcement 

agency on tribal lands. We strongly agree with the need for the identified operating, design, 

groundwater monitoring, corrective action, and closure and post-closure requirements. Office of 

Surface Mining, Reclamation and Enforcement does not have a federal action at the FCPP, but 

the BIA is a cooperating agency and is using this EIS to inform its decision on the FCPP lease 

renewal. The hazardous and solid waste mitigation measures should be conditions of BIA’s 

lease approval and enforceable through BIA’s lease conditions and its NEPA Record of 

Decision. We recommend that they be identified as such in the Final EIS. 

Contamination from past CCR mine disposal

Contamination from coal combustion residue (CCR) placed at the Navajo Mine has leached, and will 

continue to leach, directly into groundwater of the Fruitland Formation coal seams and the Pictured 

Cliffs Sandstone Formation. The DEIS acknowledges “high levels of chemical constituents of concern 

exist within the wells in the historic mining area” (p. 4.5-44). The DEIS concludes, however, that “Thus 

far, negligible impacts have resulted from the CCR placement. It is also unlikely that any significant 

future effects will ensue from the CCR placement at the Navajo Mine because of the very slow 

groundwater movement and the likely attenuation of contaminants of concern as they migrate through 

the subsurface” and that “Therefore, past CCR placement at the Navajo Mine is determined to have no 

impact in the short- or long-term” (p. 4.5-14). Elsewhere it states that the potential impacts to current 

and future water uses from CCR placement at the Navajo Mine are minor (p. 4.5-44), despite the 

identified major impacts for pH, boron, selenium, fluoride and sulfate (p. 4.5-44), with concentrations of 
2

boron, fluoride, sulfate, and total dissolved solids (TDS) exceeding the criteria for livestock watering, a 

designated post reclamation land use. 

 

These conclusions, especially that of “no impact”, do not appear to be supported. The modeling 

assumption that contaminants would be attenuated as they migrate through the subsurface has not been 

confirmed1. Additionally, the assumption that pollutants would be diluted by the larger San Juan River 

groundwater flow, even if they are not attenuated during transport to the Fruitland Formation, is brought 

into question since the transport modeling and sampling that occurred seems to have not fully 

recognized the possibility of a significant vertical (fracture) flow in the Fruitland Formation. The DEIS 

indicates that the general flow direction of groundwater in the Fruitland Formation is downward through 

the interbedded shale and coal units to the lower strata of the Fruitland Formation, with marginal upward 

movement from the Pictured Cliffs Sandstone into the Fruitland Formation (p. 4.5-13). One can infer 

from the vertical flow directions that fracture flow might play a prominent role in the movement of 

bedrock groundwater in the FCPP area2. This parameter was not considered in the groundwater 

modeling of the FCPP area. If vertical (and lateral) fracture flow is substantial, the assumed attenuation 

would not occur because fracture flow results in a much smaller residence time of groundwater in the 

bedrock formations and a limited opportunity for the contaminants to be adsorbed by bedrock clay. This 

would lead to a potentially larger groundwater impact downgradient of CCR placement than is predicted 

in the DEIS. 

The DEIS is not clear whether any ongoing groundwater or surface water monitoring would occur as a 

condition of this project. The DEIS seems to indicate that only groundwater and surface water 

monitoring that are part of the new SMCRA permit groundwater monitoring plan (originally from BHP 

Navajo Coal Company, but which the Navajo Transitional Energy Company will implement) would 

occur, which relates to the new mine areas and the Pinabete and Cottonwood arroyos. It does not 

specify any monitoring of the historic contamination areas nor confirm that contaminated groundwater is 

not reaching the San Juan or Chaco River surface water or alluvia.

Recommendation: The FEIS should include additional information to support its groundwater 

and surface water impact assessment conclusions. We recommend that monitoring of 

groundwater quality at Areas I and II of the Navajo Mine and the San Juan River alluvium occur 

to confirm the model predictions that constituents of concern would be attenuated as 

 

1 The DEIS references the “Cumulative Hydrologic Impact Assessment of the BHP Billiton Navajo Coal Company, Navajo 

Mine” for this assumption, but this assessment is not summarized nor appended to the DEIS.

2 Wilson, T.H. et al., (2012): “Fracture and 3D seismic interpretations of the Fruitland Formation and cover strata: 

Implications for CO2 retention and tracer movement, San Juan Basin Pilot test”. International Journal of Coal Geology, 

Volume 99, 1 September 2012, Pages 35–53. http://www.sciencedirect.com/science/article/pii/S0166516212000432

McCord, J. et al., (1992) “Heat-flow data suggest large ground-water fluxes through Fruitland coals of the northern San Juan 

basin, Colorado-New Mexico”, International Journal of Coal Geology, v. 20 no. 5, 1992, p. 419-422. 

http://dx.doi.org/10.1016/j.coal.2012.02.007

Haerer and McPherson (2008) “Evaluating the impacts and capabilities of long term subsurface storage in the context of 

carbon sequestration in the San Juan basin, NM and CO”. Energy Procedia, Volume 1, Issue 1, February 2009, Pages 2991–

2998. Proceedings of the 9th International Conference on Greenhouse Gas Control Technologies (GHGT-9), 16–20 

November 2008, Washington DC, USA. http://www.sciencedirect.com/science/article/pii/S187661020900719X
3

groundwater travels towards the San Juan River and the Chaco River. Because the groundwater 

of the Fruitland and Pictured Cliffs Sandstone formations that enter into the alluvium also 

discharges into the San Juan River in the area of the Navajo Mine, monitoring of the San Juan 

River surface water quality upstream, along the mine reach, and downstream should occur if the 

groundwater monitoring results identify elevated levels of pollutants in the San Juan River 

alluvium that exceed Navajo Nation Water Quality Standards.

In addition, the baseline groundwater quality should be clarified. The DEIS summarizes baseline 

results for Cottonwood, Pinabete, and No Name Arroyo alluvial wells in Table 4.5-5; however 

the presentation of this information is not useful. EPA previously commented that this summary 

does not allow an assessment of ground water impacts by source, and we recommended 

including some monitoring results by well in the DEIS. In addition, the identification/location of 

these baseline wells is of importance in order to confirm they do, indeed, represent baseline 

conditions and do not include contamination that is related to past CCR disposal. This 

information should be included in the FEIS. 

Monitoring for CCR contamination from Four Corners Power Plant

The DEIS reports two areas of groundwater seepage at the existing Dry Fly Ash Disposal Areas 

(DFADAs) known as the “north seep” and “south seepage area”, which have contaminated groundwater

(p. 4.5-57). According to the DEIS, APS has installed extraction wells and constructed the north 

intercept trench to collect seepage and prevent contamination of the Chaco River, and is currently 

constructing a south intercept trench to remediate groundwater to protect the river. The DEIS does not 

indicate how the groundwater is being remediated. With this action and the monitoring of the existing 

trenches, the DEIS concludes that continued operation and expansion of the DFADAs would have less 

potential to contaminate local groundwater and water quality in Chaco Wash (p. 4.5-57). 

We believe that such actions to capture and treat contaminated groundwater are necessary to ensure that 

the continued operation and expansion of the DFADAs does not contribute significantly to the existing 

pollutant load in the Chaco River. The operation of the intercept trenches, as well as the monitoring of 

groundwater in existing and, possibly, new monitoring wells, is critical to ensuring that any pollutant 

sources present in ground water that re-surfaces via seeps can be traced so that appropriate corrective 

actions can be undertaken. 

Recommendation: We recommend that any FCPP lease renewal by the BIA include conditions 

requiring the continued monitoring and remediation of groundwater at the DFADAs. We also 

recommend that the FEIS identify the method of groundwater remediation that is occurring or 

will occur. 

 

Dam Safety

We appreciate the information in the DEIS that states that all recommendations from the 2009 Coal Ash 

Impoundment – Site Specific Assessment Report for the FCPP were completed in 2009 (p. 4.14-4). On 

p. 4.15-22, however, the DEIS states that APS indicated that the suggested items would be addressed 

and completed prior to the end of 2009. The DEIS specifically identifies some of the recommendations,

but does not indicate whether the following are occurring: (From section 12.4 of the recommendations):

 Continue monitoring seepage at the downstream toe of the south embankment (Pond #4 toe) for 

any changes in seepage quantity and flow rate or evidence that the flow is carrying soil/ash 

particles from the embankment.
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 Expand program to include additional monitoring of potential seepage under the dam at the 

northwest corner of the LAI, where the LAI embankment was not tied-in to the underlying

Pond 3-4 embankment to provide continuity of seepage control, and where a potential seepage 

pathway exists if the HDPE lining fails. Install additional piezometers to address this potential 

seepage pathway and expand documentation in APS dam safety inspections to note any evidence 

of seepage near the downstream toe of the dam in this area. 

 Repair or replace the two settlement plates that do not appear to be providing useful information 

and that may have been damaged during construction or maintenance activities.

Recommendation: For clarity in the FEIS, indicate whether the above recommended actions and 

monitoring from the 2009 Coal Ash Impoundment – Site Specific Assessment Report for the FCPP 

are occurring. If the requested monitoring has occurred, include results of seepage monitoring 

efforts. 

Dust Control from CCR Management

The DEIS provides information regarding the FCPP Dust Control Plan. The DEIS states that, “During 

placement of CCR, compaction control, added moisture, and slope control are used, as well as dust 

suppressant and periodic fabric covering of slopes”. The DEIS states that DFADA 1 and 2 will 

continue to be used until they reach capacity in 2016. DFADA 1 is tallest on the west berm, 

approximately 110 feet above natural grade (p. 4.15-12). The DEIS also states that APS would 

construct five additional DFADAs to accommodate future disposal of all fly ash, bottom ash, and flue 

gas desulfurization waste generated through the duration of the lease term. Each site is anticipated to be 

approximately 60 acres and approximately 120 feet high (p. xiii and p. 3-15). On page 4.15-27, the 

DEIS states that the new DFADA’s would be approximately 80 feet high, so it is not clear which height 

represents the height above natural grade. 

If the height of the DFADAs will be 120 feet above natural grade, to the extent there is any settlement in 

the down-wind directions, fugitive dust control on such a high active face would be difficult to maintain. 

EPA has received complaints from nearby residents regarding fugitive dust, therefore renewed efforts at 

dust control, and monitoring of dust control effectiveness, is essential. 

Recommendation: Clarify in the FEIS whether the height of the DFADAs will be 80 feet or 120 

feet above natural grade. For either height, we recommend that the DFADAs be continuously 

sprayed with water to ensure dust is controlled. Slope control and the other dust control 

measures in the Dust Control Plan should be monitored regularly to ensure they are effective. 

When wind speeds are elevated, more frequent dust control should be implemented. 

We recommend that a dust complaint procedure and hotline be developed to allow local residents 

to report ineffective dust control conditions. APS should conduct outreach to the local 

population, in Navajo as well as English, to ensure awareness of this complaint procedure.

Cumulative Health Impacts

The EIS should acknowledge the cumulative health impacts that the residents in the vicinity of the 

project experience. The DEIS largely relies on the air quality analysis conclusions for its public health 

impact assessment. The DEIS states that the combined impacts to air quality from the Navajo Mine and 

the Four Corners Power Plant (FCPP) are minor (p. 4.1-85) because modeled criteria pollutant emissions 

meet the National Ambient Air Quality Standards (NAAQS). EPA sets the NAAQS at a level requisite 

to protect public health with an adequate margin of safety, taking into consideration effects on 
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susceptible populations, based on the scientific literature; however, as we previously commented, EPA’s 

Particulate Matter and Ozone Integrated Science Assessments (U.S. EPA, 2009 and U.S. EPA, 2013) 

determined that there is no evidence of a population-level threshold in PM- and ozone-related health 

effects in the epidemiological literature. This means that there is not a level below which is there is no 

impact. Instead, health impacts that occur below the standards are assumed to be more uncertain than 

those occurring above the standards. 

The DEIS acknowledges that the cumulative public health effects depend on the respiratory health status 

of residents in the area (p. 4.18-54), yet it does not appear that respiratory health was considered in the 

conclusions that project impacts to public health from the FCPP are negligible for criteria pollutants (p. 

xli, p. 4.17-22) and minor for hazardous air pollutants (p. p. 4.17-24), and that cumulative impacts to 

public health from both the FCPP and the Mine are minor (p. 4.18-54). The DEIS does disclose San 

Juan County’s most recent Community Health Profile, which found that San Juan County has a higher 

incidence of chronic lower respiratory disease, comprised of chronic bronchitis, asthma, and 

emphysema, compared to New Mexico or the rest of the United States. It also cites a study by the New 

Mexico Department of Health that found that San Juan County residents are 34 percent more likely to 

have asthma-related medical visits after 20 parts per billion increases in local ozone levels (p. 4.17-4). 

A study by Bunnell, et al, also cited in the DEIS, documents disproportionately high rates of respiratory 

disease in the Indian Health Service’s Shiprock Service area (p. 4.11-14). None of this information

appears to have been factored into the DEIS’ conclusions regarding cumulative public health impacts. 

The DEIS also discusses the unique situation of in-home coal burning from coal provided free of charge

to Navajos who reside within a certain radius of the mine, which was part of the original mining lease 

agreement. The DEIS states that, from October through March, coal for personal use by project 

employees and local Chapter residents is placed in the Community Coal Stockpile, located adjacent to 

the Navajo Mine Area III office (p. 2-12). Because many Navajo are able to obtain cheap or free coal, 

and they do not have access, or affordable access, to electricity – an existing environmental justice 

vulnerability -- many use coal to heat their homes. It is not unusual for the coal to be burned in stoves 

that were not designed to burn coal, nor is it unusual that the stoves are poorly maintained or improperly 

vented. The Bunnell study revealed that air quality from coal combustion inside dwellings used for 

cooking and heating had an average 24-hour wintertime PM2.5 level exceeding EPA’s ambient air 

standard for PM2.5 (note that EPA does not regulate indoor air pollution levels). This cumulative impact, 

which directly relates to the mine operations for which this EIS is being prepared, should be considered 

in the cumulative public health impact conclusions, as well as referenced in the environmental justice 

impact conclusions. 

Recommendation: We recommend that the cumulative public health impact assessment 

conclusions factor in the respiratory health status of residents in the area, as the DEIS states 

should occur on page 4.18-54. The FEIS should document how the lack of access to electric 

power and the provision of free or low-cost coal by the project have contributed to indoor air 

quality cumulative impacts, as well as outdoor air pollution during stagnant winter weather 

conditions. Because the DEIS does not define what would constitute a moderate or major impact 

to cumulative public health and does not define a level of significance, we recommend 

identifying mitigation measures for this impact, since the existing public health environment is 

severely compromised (health outcomes for Navajo are worse than for the general population in 

San Juan County; life expectancy is lower, mortality rates far exceed the national rates; 

investment in healthcare services on Navajo land is about half of that for the general population; 

and healthcare disparities between Navajo and the general population are pronounced due to lack 
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of access and funding - p. 4.10-15). The DEIS notes that the results from the Bunnell study 

suggest that the added risk from in-home coal burning could be reduced by making relatively 

simple and inexpensive changes to methods of home heating (p. 4.17-4). Such changes should 

be further discussed and identified as possible mitigation for this cumulative public health and 

environmental justice impact. 

EPA previously recommended mitigation for cumulative impacts from in-home coal combustion

supplied by the continued operation of the mine. At a minimum, the following potential 

mitigation measures should be identified and considered: funding for replacement of old stoves 

with more efficient stoves appropriate for the fuel types being used; funding for replacement of 

old coal and wood stoves with propane gas heaters; assistance to the affected community for 

residential solar, wind or other electrical generation projects; assistance to Navajo Tribal Utility 

Authority for local electricity connections and subsidies to any affected residents; and education 

on how to properly operate, vent, and maintain existing stoves, perhaps locating this information 

in Navajo at the Community Coal Stockpile or producing an instructional video to play in Indian 

Health Service clinic waiting rooms. Selection of any of the above measures should be done in 

consultation with the affected residents. 

Excluding Fugitive Dust from the Human Health Risk Assessment (HHRA)

EPA previously commented that fugitive dust should have been included in the Human Health Risk 

Assessment and that uncertainty regarding the assumption of equal toxicity of PM species does not 

warrant the exclusion of fugitive dust from the impacts analysis (on the basis of having a lower 

proportion of metals and other toxic substances). OSM has chosen, instead, to include a discussion of 

potential impacts from PM2.5, including baseline and projected future emissions. 

Recommendation: We recommend that the FEIS clearly state that fugitive dust was not included 

in the HHRA. 

Potential for Mine Methane Capture

The DEIS quantifies the fugitive methane emissions that would be liberated from coal seams during 

mining (p. 4.2-22). Methane has a global warming potential more than 20 times higher than CO2 for a 

100-year period3. Methane can be captured at surface mines through pre-mine drainage, either from the 

surface or through horizontal boreholes. EPA is aware that there are surface mines in operation in the 

Powder River Basin in Wyoming and elsewhere around the world that are recovering methane through 

pre-mine drainage and, thus, mitigating the impact from this powerful greenhouse gas. Also note that 

surface mine methane capture is now eligible for carbon credits - a market tracking system that supports 

the implementation of California’s Cap-and-Trade Program - for greenhouse gas emission reductions 

associated with the capture and destruction of methane in the U.S. that would otherwise be vented into 

the atmosphere as a result of mining operations at active underground and surface coal mines. See: 

http://www.arb.ca.gov/newsrel/newsrelease.php?id=602. In addition, the DEIS states that BIA is 

currently evaluating, under NEPA, Western Oil & Gas’s proposal to develop 600 natural gas wells in the 

Burnham, Upper Fruitland, and Nenahnezad/San Juan Chapters, which would involve the installation of 

new pipeline (p. 4.18-13). 

 

3 http://www.epa.gov/climatechange/ghgemissions/gases.html
7

Recommendation: We recommend that the FEIS discuss the feasibility of capturing methane 

from Navajo Mine. Include the economic benefits that could occur from selling the carbon 

credits in California’s Cap-and-Trade Program, as well as the possible interconnection or use of 

natural gas infrastructure nearby from Western Oil & Gas’s proposed natural gas wells.

Additional information regarding methane recovery at surface mines is available in the following 

EPA documents: 

 “Case Study – Methane Recovery at Surface Mines” -

http://epa.gov/coalbed/docs/CMOP-Methane-Recovery-Surface-Mines-March-2014.pdf

 “US Surface Coal Mine Methane Recovery Opportunities” -

http://epa.gov/coalbed/docs/cmm_recovery_opps_surface.pdf

Petroleum Contamination

The DEIS states that “Secondary containment is not provided for mobile refueling vehicles in areas 

where NTEC staff are present, and the maximum amount of time before a discharge would be detected is 

less than 24 hours” (p. 4.15-6). It is unclear why it could take hours before a discharge from mobile 

refueling is detected. The DEIS states that the bioremediation of petroleum-contaminated soils takes 

place on-site (p. 4.15-6). The source of this contaminated soil is not identified. 

Recommendation: The FEIS should identify the source of the petroleum-contaminated soils and 

indicate whether they are originating from mobile refueling operations. We recommend that the 

applicant review and, as needed, update its Spill Prevention, Control, and Countermeasure 

(SPCC) Plan to identify applicable general containment or drainage control measures, as 

required by 40 CFR 112.7(c) for mobile refuelers and mobile refueling, to ensure that releases 

associated with these operations are detected as soon as possible. For the continued operation of 

the FCPP and Navajo Mine, we recommend that additional measures be explored to prevent and 

contain releases when mobile refuelers may be unattended and during mobile refueling 

operations. 

Additional comments

 Table 4.1-28 on p. 4.1-67 is confusing. The second column is labeled “Estimated Post-2014 

Baseline Emissions”, but it is not clear what is meant by post-2014 emissions. The text says that 

the reductions in the third column represent the reductions from fully implementing BART, but 

our estimate for mercury reductions under BART implementation is 61%, not the 81% listed. It 

is possible that the table is intended to represent the additional reductions in mercury that could 

occur from implementation of the mercury and air toxics standards (MATS). If so, this should 

be clarified in the FEIS and a definition of “Post-2014 Baseline Emissions” should be provided.

 In Table 4.5-6 on page 4.5-20, the result for mercury is listed as >0.001. Should this have been

<0.001? 

 In the Hazardous and Solid Waste chapter, the PDEIS states that “specific study of the disposal 

of CCR in Navajo Mine has not identified adverse effects” (p. 4.15-5). This does not appear to be 

supported, given the contamination identified in the Water Resources chapter. Groundwater 

contamination is an adverse effect.