Excavating the regulatory process and risks posed by Alaska hardrock mine expansions
Abstract
Mining can cause environmental damage if managed improperly. Environmental impact assessments are designed to evaluate the risks of mining; however, these evaluations are hindered when mines expand their operational scope beyond activities considered in the original assessment. Our study focuses on the regulatory process of mine expansion and the National Environmental Policy Act (NEPA). Our multiple case study approach analyzed expansion projects for five hardrock mines in Alaska, USA. A media review identified expansion issues for each mine that received significant public attention. For each case, we examined government documents, media, and other literature to explore research questions related to variability in the application of environmental impact assessment procedures, the breadth and depth of public process, and issues raised during public comment periods. Across case studies, we synthesized the common themes and context dependence regarding the regulatory process of mining expansion. We found wide variation in the implementation of NEPA based on different institutional and geographic contexts, which led to unique sets of public concerns. We summarized differing levels of public engagement, varying approaches to cumulative effects analyses, and difficulties accessing public documents. These results demonstrate the challenges that mine expansions pose to conducting consistent and transparent environmental impact assessments.
Graphical Abstract
Introduction
As Earth's atmosphere warms, society's reliance on green energy infrastructure to reduce carbon output increases the demand for minerals that contain metallic elements, such as lithium, cobalt, and copper (Valero et al. 2018; Herrington 2021; Agusdinata and Liu 2023). While use of these metals may help mitigate climate change impacts, their extraction creates social and ecological risks that are often disproportionately concentrated on communities adjacent to mining operations (Dudka and Adriano 1997; Rodríguez-Labajos and Özkaynak 2017). These trade-offs are especially striking in northern latitudes, which include some of the fastest warming (Previdi et al. 2021) and most mineral-rich regions on Earth. Moreover, many northern mining operations focus primarily on gold, the majority of which is used for luxury items and investment demand, whereas only 8% is used for technology (Lezak et al. 2023). In northwestern North America, thousands of historical hardrock and coal mines dot the landscape, and dozens of currently proposed or operating mines extract industrial-scale volumes of earth from the ground (Sergeant et al. 2022). Mining operations in this region often overlap with ecologically sensitive areas and may have complex effects on economies and ways of life for rural and Indigenous communities (Gibson and Klinck 2005; Guettabi et al. 2016).
The negative social–ecological impacts potentially resulting from mining include increased contaminant concentrations in fish and wildlife, reduced air and water quality, altered viewscapes in populated or tourist areas, and filling of wetlands (Starnes and Gasper 1995; Spitz and Trudinger 2019; Tolvanen et al. 2019; Dentoni et al. 2020; Dunbar 2024). The effects of mining can be chronic, such as the long-term increase of selenium in fish to toxic levels (Miller et al. 2013) or the persistent leaching of acid mine drainage into adjacent waterbodies (Blowes et al. 2014). Mining effects can also be immediate and catastrophic, such as the tailings dam failure at Mount Polley Mine in 2014 that released millions of m3 of mine waste into the upper Fraser River watershed of British Columbia, Canada (Petticrew et al. 2015). Within a watershed, the impacts of mining, if improperly managed, can extend several to hundreds of kilometers downstream from the original source (Moore and Luoma 1990; Storb et al. 2023). The cumulative impacts of multiple stressors on people and the environment that are posed by mining are complex and often poorly understood (Dubé et al. 2006; Côté et al. 2016). Because of the complexity and place-based nature of mining impacts, regulatory and permitting review processes required for mine development are important mechanisms for documenting and mitigating the range of ecological and social effects posed by individual mining operations.
During the environmental impact assessment process—a general term for the government-led process of reviewing project impacts and proposing actions that mitigate damage to the environment—regulators investigate the ways in which a mining project may affect the surrounding environment (Morgan 2012). One necessary step for assessing the environmental risks of an individual mining project is to accurately identify the breadth and magnitude of operations, including components such as earth removal and processing rates, water usage, and mine waste storage volume (Sergeant et al. 2022). In the United States, the key federal law guiding environmental assessment is the National Environmental Policy Act of 1970 (NEPA; 42 U.S.C. §§ 4321 et seq.). NEPA provides a framework under which federal agencies are obligated to assess the potential environmental impacts of their proposed activities prior to acting. Importantly, NEPA offers opportunities for the public to participate in meetings and written comment periods during multiple stages of the assessment, which can occur within an environmental assessment (EA) or the much more comprehensive environmental impact statement (EIS). For a mining project, the NEPA process is initiated when the federal government is required to take certain major actions, such as approving a permit for the disturbance of wetlands or for construction on federal lands. While NEPA is, in part, intended to provide transparency during the decision-making process, the perceived success of this intent has varied amongst members of the public (Teschner 2021).
Adding to the complexity of assessing changing risks associated with mining, mines frequently undergo expansion activities beyond their original project scope. Mining companies often continue exploration in the project area and decide whether it is economically feasible to exploit new deposits (Abdel Sabour and Poulin 2010). While anticipated expansions beyond the original mining project scope may be reviewed during the original environmental impact assessment process, they are more commonly addressed via subsequent regulatory and/or permitting processes (see examples in Kuipers et al. 2006). This is a concern because a recent Canadian study revealed that mines regularly used a less rigorous amendment process for expanding mining operations, including activities that present risks to aquatic resources (Collison et al. 2022). Despite the commonplace nature of mine expansions and their potential for cumulative social–ecological impacts, we know of no studies assessing the transparency and consistency of the regulatory and public participatory process for amending mining impacts in the United States. In the United States, expansions may result in a new EA or EIS, but these assessments are based on the impact of the new expansion and do not necessarily focus on cumulative effects of the entirety of the mine or consider the potential for future expansions (McCold and Holman 1995; Smith 2006). Smaller expansion projects deemed by the federal government to not pose a significant impact to the environment can proceed without a public-facing assessment, or may undergo assessments at smaller jurisdictional scales (e.g., state level).
Here, we examine the process of mine expansion in Alaska, USA, a key region for current and future mineral production in the United States (USGS 2024). Alaska currently has six large operating mines: five that target hardrock minerals and one targeting coal. In 2021, products exported from these six mines earned $2.1 billion, amounting to 35% of Alaska's total exports (McKinley Research Group 2022). These mines directly employed approximately 5400 people and distributed $625 million (2021 USD) in wages in 2021 (McKinley Research Group 2022). There are approximately 10 large and many smaller exploratory mining operations currently underway in Alaska, and one large proposed open pit mine, the Donlin Gold Project (https://dnr.alaska.gov/mlw/mining/large-mines/). The Alaska watersheds in which these mining operations are located also provide critical ecosystem services, such as harvestable salmon populations and drinking water (Augerot and Foley 2005; Marino et al. 2009). Therefore, Alaska represents a globally important mineral hotspot where resource extraction often overlaps with ecosystems that support livelihoods and subsistence (Woody et al. 2010).
In this study, we used a multiple case study approach to examine the environmental impact assessments and associated public processes through which Alaska's five producing hardrock mines have expanded over time. For each case, we reviewed government documents, public media, and other literature to explore a set of guiding research questions: (1) How was environmental impact assessment applied in the context of each expansion? (2) How did the process vary based on land ownership or other jurisdictional factors? (3) What was the breadth and depth of the associated public process for each expansion issue? (4) What issues were raised through public comments regarding hardrock mining expansions and how were they addressed through the NEPA process (where applicable)? We then compared case studies to synthesize the common themes and context dependence regarding the regulatory process of mining expansion, including the degree of process transparency and consistency of public engagement during EA.
Methods
Study sites
Our study focuses on the five hardrock mines of Alaska, which cross an expansive mosaic of ecotones and decision-making jurisdictions (Fig. 1). Red Dog Mine is a polymetallic mine primarily producing lead and zinc and located on northern tundra lands managed by Northwest Arctic Native Association Regional Corporation, Inc. (NANA). Greens Creek Mine and Kensington Gold Mine are located in the coastal temperate rainforest of southeastern Alaska and situated within the Tongass National Forest, federal lands administered by the United States Forest Service (USFS). Greens Creek is another polymetallic mine producing gold, lead, silver, and zinc, and Kensington produces only gold. Pogo and Fort Knox Gold Mines are in the interior boreal forest and fall within state land managed by the Alaska Department of Natural Resources (ADNR). Each mine, therefore, must balance economic development with the protection of cultural and ecological resources. Due to the breadth and complexity of operations, regulations, permits, and policies related to mining in Alaska, we provide readers with four tables summarizing mining terms (Table 1), regulatory terms (Table 2), relevant agencies (Table 3), and relevant laws and policies (Table 4).
Fig. 1.
Table 1.
| Term | Definition |
|---|---|
| Acid mine drainage | Wastewater from mining activities that has become acidic due to oxidation of sulfides |
| Heap leach | Process that uses chemicals to irrigate crushed, low-grade ore to extract the mineral commodity of interest, such as gold or silver |
| Mill | A facility where ore is ground to a reduced particle size and valuable metals are removed via physical or chemical treatment |
| Mining slurry | Crushed ore that is mixed with water in a mill |
| Open pit mine | Mining operation removing minerals entirely from the surface |
| Ore | Solid material containing the commodity of interest, such as gold or silver |
| Reclamation | Actions designed to make a mine that has ceased operations blend in with the surrounding landscape and possibly become usable land; often includes restoration and environmental monitoring efforts |
| Tailings | Waste product resulting from processing ore; not to be confused with waste rock |
| Tailings storage facility | Tailings are stored in either reservoirs as a saturated slurry or dry stacks after most water content has been removed |
| Underground mine | Mine whose footprint is mainly underground in shafts and tunnels to access ore deposits |
| Waste rock | Rock that has little to no ore that must be removed to access ore |
Note: The definition of heap leach was paraphrased from Ghorbani et al. (2016), while the remaining definitions were paraphrased from Dunbar (2024). We refer readers to more detailed descriptions of mining in Whyte and Cumming (2007) and Dunbar (2024).
Table 2.
| Term | Law | Definition |
|---|---|---|
| Alternatives | NEPA | Each proposed action is accompanied by various alternatives that may produce different environmental outcomes; among these alternatives are the “preferred” alternative and the “no action” alternative |
| Environmental assessment (EA) | NEPA | Analysis that determines whether or not a federal action has the potential to cause significant environmental effects; can result in finding of no significant impact or EIS |
| Environmental impact statement (EIS) | NEPA | Robust analysis of the impacts (e.g., social, ecological) of a proposed action; first published as a draft EIS, then undergoes a public comment period, after which the draft is amended into a final EIS that responds to comments |
| Essential fish habitat | MSFCMA | Waters and substrate necessary for fish spawning, breeding, feeding or growth to maturity (16 U.S.C. §§ 1801 et seq.) |
| Fill material | CWA | Rock, sand, dirt, or other material necessary for the construction of any structure in waters of the U.S. (43 CFR § 232) |
| Finding of no significant impact | NEPA | Document that presents reasons why the agency has concluded that no significant impacts are projected for a particular action |
| Notice of availability | NEPA | Announcement in the Federal Register that the prepared EIS (draft or final) is available |
| Notice of intent | NEPA | Public announcement in the Federal Register that informs the public of an upcoming environmental analysis, describes how the public can become involved, and initiates the scoping period |
| Plan of operations | BLM/USFS mining regulations | Document describing proposed operations with sufficient details to determine whether activities would cause “unnecessary or undue degradation” of public lands (43 CFR § 3809.401 and 36 CFR § 228.3). |
| Record of decision | NEPA | Document that explains the agency's decision, describes the alternatives considered, and discusses agency's plans for mitigation and monitoring as necessary |
| Supplemental environmental impact statement (SEIS) | NEPA | Analysis of a substantial proposed change to a previous action (i.e., EIS); follows the same process as an EIS |
Note: Definitions are paraphrased from the U.S. Environmental Protection Agency (https://www.epa.gov/nepa/national-environmental-policy-act-review-process) unless otherwise stated. NEPA = National Environmental Policy Act; MSFCMA = Magnuson–Stevens Fishery Conservation and Management Act; CWA = Clean Water Act.
Table 3.
| Agency | Jurisdiction | Role | Relevant case study |
|---|---|---|---|
| National Marine Fisheries Service (NMFS) | Federal | Oversaw ESA and MMPA compliance | Greens Creek, Kensington |
| U.S. Army Corps of Engineers (USACE) | Federal | Administered Clean Water Act §404 permit | Fort Knox, Greens Creek, Kensington, Pogo, Red Dog |
| U.S. Environmental Protection Agency (USEPA) | Federal | Lead agency on SEIS (Red Dog Aqqaluk); NEPA cooperating agency (Greens Creek, Kensington); CWA implementation or oversight; CAA oversight | Greens Creek, Kensington, Red Dog |
| U.S. Fish and Wildlife Service (FWS) | Federal | Oversaw ESA and major wildlife act compliance | Greens Creek, Kensington, Red Dog |
| U.S. Forest Service (USFS) | Federal | Lead agency on SEIS, issued record of decision; approved mine expansion plan of operation | Greens Creek, Kensington |
| Alaska Department of Environmental Conservation (ADEC) | State | Oversaw compliance with CWA and CAA permitting (Greens Creek, Kensington) | Fort Knox, Greens Creek, Kensington, Pogo, Red Dog |
| Alaska Department of Fish and Game (ADF&G) | State | Oversaw fish habitat protection and passage permitting | Greens Creek, Kensington, Red Dog |
| Alaska Department of Natural Resources (ADNR) | State | Lead agency on State of Alaska permitting and reclamation plan approval | Fort Knox, Greens Creek, Kensington, Pogo, Red Dog |
| City and Borough of Juneau (CBJ) | Municipal | Participated in NEPA/SEIS process | Greens Creek, Kensington |
Note: The agency column is sorted alphabetically within each jurisdiction (federal, state, municipal). Acronyms related to laws and policies listed in the Role column are defined in Table 4.
Table 4.
| Law or policy | Year passed | Description |
|---|---|---|
| Alaska National Interest Lands Conservation Act | 1980 | Establishes protections within Admiralty Island National Monument |
| Bald and Golden Eagle Protection Act | 1940 | Regulates protection of bald and golden eagles |
| Clean Air Act (CAA) | 1963 | Regulates all sources of air emissions |
| Clean Water Act (CWA) | 1972 | Regulates discharge of pollutants into U.S. waters; Defines the terms of the National/Alaska Pollutant Discharge Elimination permits |
| Endangered Species Act (ESA) | 1973 | Regulates compliance with Section 7 interagency consultation |
| Executive Orders 11988, 11990, 12898, 12962, 13077, 13112, 13175 | Varies | Regulates project compliance with all Federal executive orders |
| Fish and Wildlife Coordination Act | 1934 | Regulates impacts on fish and wildlife |
| Freedom of Information Act | 1967 | Requires the partial or full disclosure of U.S. governmental documents |
| Forest Plan | 2008 | Guides forest management and conservation efforts |
| Forest Service Roadless Area Conservation Rule | 2001 | Regulates protection of roadless areas within National Forest System lands |
| General Mining Law | 1872 | Allows U.S. citizens to explore for and purchase certain mineral deposits on federal land where mining is allowed |
| Greens Creek Land Exchange Act | 1995 | Allows Tongass National Forest land to be explored and developed for mining |
| Marine Mammal Protection Act (MMPA) | 1972 | Regulates compliance with Section 7 interagency consultation |
| Magnuson–Stevens Fishery Conservation and Management Act (MSFCMA) | 1976 | Regulates compliance with Section 305 consultation |
| Migratory Bird Treaty Act (MBTA) | 1918 | Maintains populations of all protected migratory bird species |
| National Environmental Policy Act (NEPA) | 1970 | Establishes framework to guide agency assessment of environmental impacts of proposed decisions |
| National Historic Preservation Act (NHPA) | 1966 | Regulates Section 106 compliance |
| Wilderness Act | 1964 | Establishes national network of federally designated and managed wilderness areas |
| Alaska Native Claims Settlement Act | 1971 | Conveys over 45 million acres (>18 million ha) of land to village and regional Native corporations |
| City and Borough of Juneau Comprehensive Plan | 2008 | Outlines approach to community growth and development of CBJ |
| City and Borough of Juneau Exploration and Mining Ordinance | Varies | Establishes how federal, state, and local mining ordinances coordinate |
Note: The law or policy column is sorted alphabetically within each hierarchical jurisdiction (i.e., federal to municipal). This table should not be considered a comprehensive list of all laws and policies related to mining operations in Alaska.
Case study approach
Because of the complexity and place-based nature of mining operations and their impacts, we determined that a comparative case study approach (Yin 2018) would allow for greater generalizability of central themes emerging from examination of hardrock mine impact assessment in Alaska. First, we conducted a media search (detailed below) to identify key expansion issues that were in the public discourse for each of the selected hardrock mines in Alaska; each expansion issue formed the basis of a case study. For each focal mine and expansion issue, we reviewed a diversity of publicly available print and online sources to address the guiding research questions. Our primary data sources were the original EA/EIS of each mine and the primary documentation supporting the expansion, including the EA/EIS, supplemental EIS (SEIS), Public Notice for Application of Permit, and the associated public comments for those documents. Based on documentation from the Council on Environmental Quality (2021), an EA is used to determine the significance of the environmental effects and whether a more detailed analysis in the form of an EIS is required. While the requirements for public input are well defined within an EIS process, during the preparation of an EA, agencies have discretion to determine the extent of public involvement. We acquired these documents using a combination of online repositories, agency contacts, and Freedom of Information Act requests. Our focus was primarily on the NEPA process related to these expansions, with some discussion of federal, state, and municipal permits, but the study was not fully inclusive of non-federal permitting processes. We synthesized findings across case studies to identify common themes regarding the regulatory process of mining expansion, with a particular focus on process transparency and consistency of public engagement during environmental impact assessment.
We achieved rigor in our research design using the case study criteria described by Yin (2018). Construct validity, or use of appropriate measures for concepts being studied, was accomplished through an intensive review of publicly available documents regarding the mines and their expansion issues. Because mines are run by private corporations, documentation on their operations can be confidential or difficult to locate. With the assistance of a public policy research librarian at the University of Washington (E. Keller), we drew from government documents, public comment records, news media, industry reports, and other online sources. External validity, or generalizability, was achieved through a case study narrative structure that facilitated comparison of key elements across the Alaska case studies, ground truthing our findings with knowledgeable experts (e.g., government agency staff who coordinated NEPA processes), and broader comparison of our findings to published literature on mining operations outside of Alaska within the Discussion section. Reliability (replicability) of our case study findings was achieved through careful documentation and our reporting of our process and sources (this manuscript).
Selection of case studies
Because of the large number of expansions over many years, it was necessary to identify one key expansion issue to focus on for each mine. There is no central database for identifying expansions associated with individual mines in this region, so we used media coverage as a proxy for public interest in identifying focal expansion issues. We queried Alaska news sources in the Access World News (NewsBank, Inc.) database from 2000 through 2023 using Boolean search terms “mine” AND the name of the respective mine (i.e., “Red Dog”, “Greens Creek”, “Kensington”, “Fort Knox”, “Pogo”; June–August 2023). We narrowed this initial search to target expansion, amendment, or modification activities by including additional search criteria (expa* OR amen* OR modi*). This filtering reduced the numbers of relevant articles from a range of 1073–2367 per mine to 231–571 per mine (Fig. 2). From this filtered list, we excluded sources that contained the search terms but did not reference the expansion, amendment, or modification of each mine. We then reviewed each source for clear relationships to mining expansion issues for each respective mine, resulting in 25–211 relevant articles per mine (Fig. 2). From these sets of relevant articles, we picked one expansion topic with the greatest media exposure for four of the five mines analyzed. Pogo Mine did not have an apparent expansion topic with media coverage, so we focused on the two most recent expansions for this mine.
Fig. 2.
Results
The case studies are presented as descriptive narratives, structured as follows: (1) mine history, setting, and operations; (2) description of key expansion issue, including laws and agencies involved and primary social–ecological impacts identified in the assessment process; (3) public process, Tribal engagement, and agency response; and (4) summary of key findings. We present the case studies in order from longest to shortest operating mine life and highest to lowest jurisdictional and regulatory complexity. We end this section with a synthesis of common findings across case studies relative to the four research questions posed in the Introduction.
Red Dog case study
History, setting, and operations
The Red Dog Mine is one of the world's largest open pit lead and zinc mines (Table 5). Red Dog is located 132 km north of Kotzebue, Alaska, and 74 km from the western Alaska coastline. An 84 km haul road connects the mining site to port facilities along the Chukchi Sea, where concentrate is shipped for further processing (USEPA 2009). The mined land is owned by the NANA Regional Corporation, which works in partnership with the mine operator, Teck Alaska (hereafter, Teck;Fig. 1).
Table 5.
| Red Dog1,2,3,4 | Greens Creek5,6,7,8,9 | Kensington10,11,12,13 | Fort Knox14,15,16 | Pogo17,18 | |
|---|---|---|---|---|---|
| Location | 68.07, −162.85 | 58.13, −134.75 | 58.85, −135.09 | 65.00, −147.34 | 64.45, −144.90 |
| Materials mined (2022 production) | Zinc (553 100 mt) | Silver (9741 935 oz) | Gold (109 061 oz) | Gold (291 249 oz) | Gold (215 671 oz) |
| Lead (79 500 mt) | Gold (48 216 oz) | ||||
| Zinc (52 312 mt) | |||||
| Lead (19 480 mt) | |||||
| Operational aspect | Open pit | Underground | Underground | Open pit | Underground |
| Year original EIS published | 1984 | 1983 | 1992 | 1993* | 2003 |
| Commenced production | 1989 | 1989 | 2010 | 1997 | 2006 |
| Year of public notice for the case study SEIS | 2007 | 2010 | 2020 | 2001* | 2020/2022† |
| Current ownership | Teck Cominco Alaska | Hecla Greens Creek Mining Company | Coeur Alaska | Kinross Gold | Northern Star Resources |
| Land ownership and management | NANA Regional Cooperation | United States Forest Service | United States Forest Service | State of Alaska Department of Natural Resources | State of Alaska Department of Natural Resources |
| Number of employees (2022) | 644 | 491 | 395 | 732 | 610 |
| Annual revenue (2022 in millions USD) | $2111 | $335 | $183 | $522 | $363 |
| Financial assurance (millions USD; current as of 2022) | $629 | $92 | $43 | $102 | $72 |
Note: oz = ounces; mt = metric ton.
*
Fort Knox was originally permitted and operates under an EA with a finding of no significant impact rather than an EIS; in 2001, True North Mine, a satellite mine using the Fort Knox mill, applied to the State of Alaska for an amendment to their plan of operations.
†
In 2020 and 2022, ACOE provided public notices for applications of permits submitted for Pogo Mine; an SEIS was not required for expansion.
References: 1. Teck Resources Limited (2023); 2. U.S. Environmental Protection Agency, U.S. Department of the Interior (1994); 3. Alaska Department of Natural Resources (2022); 4. Alaska Department of Environmental Conservation (2018); 5. U.S. Forest Service (1983); 6. U.S. Forest Service (2013); 7. Hecla Mining Company (2022a); 8. Hecla Mining Company (2022b); 9. Hecla Mining Company (2020); 10. Coeur Mining (2021); 11. U.S. Forest Service (1992); 12. Coeur Mining (2022); 13. Alaska Department of Natural Resources, Alaska Department of Environmental Conservation, and U.S. Department of Agriculture (2017); 14. Fairbanks Gold Mining, Inc. (1993); 15. Fairbanks Gold Mining, Inc. (2023); 16. Kinross Gold Corporation. (2023); 17. U.S. Environmental Protection Agency (2003); 18. Northern Star Resources Limited (2022).
Red Dog exploration began in 1980 and full operation began in 1989 after undergoing an EIS (USEPA 2009). The U.S. Environmental Protection Agency (USEPA) and the U.S. Department of Interior served as co-lead agencies on the EIS, which was initiated in 1981 and completed in 1984 (Teck Resources Limited 2017). Construction and operation of Red Dog required permits administered by several agencies, including the U.S. Army Corps of Engineers (USACE), Alaska Department of Environmental Conservation (ADEC), and Alaska Department of Fish and Game (ADF&G) (Tables 3 and 4).
Key expansion issue
Red Dog initially extracted ore from the Red Dog Main deposit, but due to diminishing ore levels, Teck pursued permits to expand operations to the nearby Aqqaluk deposit and extend the life of the mine to approximately 2031 with a second open pit (USEPA 2009). In response, an SEIS was initiated by the USEPA in 2007, completed in 2009, and included opportunities for the public to comment (USEPA 2009). Several state and federal agencies and the Northwest Arctic Borough were responsible for administering permits in accordance with a range of laws focused on air and water quality, aquatic resources, land use, reclamation, and pollution mitigation (Tables 3 and 4).
The Public Notice for Application Permit created by the USACE noted that the Aqqaluk pit would disturb 99 hectares, 48 of which included wetlands (USEPA 2009). Direct habitat loss arising from mining construction, operations, and associated infrastructure was estimated to impact 738 ha in the initial EIS, but increased to 848 ha in the SEIS (USEPA 2009). Public comments on the SEIS from Kivalina residents, for example, shared concerns about Red Dog's impacts on human health, environmental degradation, and subsistence resources (Teck Resources Limited 2017; see additional discussion of impacts in Text S1). The USEPA identified an environmentally preferred alternative to address key concerns but lacked the authority to require its adoption (USEPA 2009). A lesser preferred alternative met the point source discharge requirements, but many community members expressed dissatisfaction with the process and with the mine's expansion, as noted in the public comments in the 2009 Red Dog Mine Aqqaluk Expansion SEIS (USEPA 2009).
Public process, tribal engagement, and agency response
Prior to expanding the mine footprint in 2010, the USEPA was responsible for engaging with the public through the SEIS process. A public notice was posted in the Federal Register in August 2007 announcing a public scoping period that concluded in October 2007 (Federal Register 2007). The USEPA invited local, state, and other federal agencies, Alaska Native Tribes, and members of the public to comment on the SEIS scope (Federal Register 2007). Initial scoping meetings were held in four communities during October 2007 (223 comments submitted; USEPA 2009). In January 2009, a little over a year after the initial scoping process, a combined SEIS and health impacts assessment was created by the USEPA to determine potential impacts to the environment and human health. The public was provided with opportunities to comment on these documents (USEPA 2009).
The public comment process resulted in various opinions for and against Red Dog's expansion. Common themes discussed amongst commenters included impacts on human health, subsistence hunting, caribou migrations, subsistence fishing, fugitive dust and air quality, water quality, and the Cape Krusenstern National Monument (USEPA 2009). Comments were submitted by a diverse group of Alaska Native and non-native residents, elected officials, NANA shareholders, current and former Red Dog workers, other mining industry professionals, and representatives from environmental and social justice non-profit organizations (USEPA 2009). In addition to stating concerns about the Red Dog expansion, many public commenters sought clarifying information without voicing a particular stance on the mine. The USEPA responses to the public comments included confirming receipt of comments, adding clarifying language in the final SEIS, and addressing new concerns (USEPA 2009). In some cases, the USEPA either stated that there was not enough evidence to draw conclusions about Red Dog's impact or that it was not within the scope of NEPA to address these concerns (USEPA 2009).
In concert with the public notices described above, the USEPA initiated consultation with Tribal governments in 2007 (USEPA 2009). In a public comment submitted to the USEPA, the Alaska Community Action on Toxics stated that the USEPA had failed in its responsibility to consult with Tribes (USEPA 2009). The USEPA responded to this comment that Tribal consultations had occurred and were noted in the SEIS (USEPA 2009). Nine Tribal governments participated as cooperating agencies for reviewing and developing the SEIS, which is unique across the case studies presented here. In addition, the Kivalina Tribal Council requested government-to-government consultation and had two meetings with the USEPA, NPS, and ACOE representatives (USEPA 2009). After the draft SEIS was issued, the Point Hope Tribal Council also requested government-to-government consultation. The USEPA reported that they did not receive a response following communication requests to set up a consultation meeting, so this meeting did not occur (USEPA 2009). In October 2009, Tribes in the region received a Public Notice of Application for Permit from USACE.
Summary
Relative to the remaining four case studies, the SEIS for the 2010 Aqqaluk expansion was unique in its inclusion of nine Tribal governments as cooperating agencies. Hundreds of public comments were received during the environmental review process that represented diverging public sentiments from community members weighing the benefits of jobs and revenue streams against their concerns for Red Dog's potential impact on subsistence harvests, environmental degradation, and human health. While the initial EIS for Red Dog estimated that habitat loss from mining operations would cover 738 ha, this area increased to 848 ha during the Aqqaluk expansion. The SEIS provided monitoring information on subsistence resources from pre-mining to pre-expansion dates and determined that the road and port operations had impacts on subsistence resources, but due to data limitations related to health, it was not possible to correlate any changes in subsistence resources or human health to mining operations. This highlights the importance of creating pre-project baseline datasets and/or monitoring unimpacted reference zones to facilitate analyses of environmental and social change during and after mining operations.
Greens Creek case study
History, setting, and operations
Greens Creek Mine is located 29 km southwest of Juneau, Alaska, near Hawk Inlet and is situated within USFS-administered Admiralty Island National Monument and Tongass National Forest (Fig. 1; Table 3; USFS 2013). As of 2024, Greens Creek was the largest silver mine in the United States, also mining gold, lead, and zinc (Table 5). Initial exploration and the staking of mineral claims began in 1974 with the USFS leading the NEPA process and EIS development shortly after (USFS 2013). The mine's original EIS was finalized in 1983 with mine production commencing in 1989 (USFS 2013).
Key expansion issue
By 2010, the accelerated mining rate at Greens Creek led to the dry stack tailings storage facility reaching capacity years before the original estimate of 2019 or later (USFS 2013). In response, Hecla Greens Creek Mining Company (hereafter, Hecla) made a request to the USFS to modify the mine's general plan of operations to expand the tailings storage area by 7 ha and prolong the mine's lifespan by 10 years (USFS 2013). This expansion would accommodate an additional 10.9 million m3 of tailings and waste rock (USFS 2013).
This request initiated the SEIS scoping process in October 2010. The USFS collaborated with state and other federal agencies to develop four action alternatives. Aside from the no action alternative, the major difference among the remaining four alternatives was the location and arrangement of the expanded tailings storage facility (USFS 2013). The USFS selected an alternative that would expand the existing tailings storage facility further into the Admiralty Island National Monument (USFS 2013). In August 2013, the USFS released their Record of Decision and final SEIS (USFS 2013). This process incorporated input from nearby communities as well as Alaska Native governments and corporations.
The 2013 dry stack tailings expansion project navigated both state and federal environmental regulation requirements (USFS 2013; Tables 2–4). The USFS was the lead agency responsible for ensuring the expansion's compliance with multiple laws and played a primary role in determining how Greens Creek could expand into the future (USFS 2013). The final SEIS was also compliant with multiple federal executive orders related to Tribal consultation, wetland protections, and other requirements (Tables 2–4). The public comment period for the draft SEIS revealed four primary ecological concerns: regional water quality degradation, nearby wetland impacts, key fish habitat degradation, and expansion into the Admiralty Island National Monument (USFS 2013; see additional discussion of impacts in Text S1).
Public process, tribal engagement, and agency response
To initiate the public scoping process required by NEPA, the USFS published a Notice of Intent in October 2010 for planned SEIS preparation regarding the tailings disposal facility expansion (USFS 2010a). Additional outreach through public notices in newspapers and emails provided information on opportunities for participating in the public comment period (USFS 2010b, 2013). Public meetings held in two communities drew participation from state and federal agencies, non-governmental organizations, and Tribal governments and corporations (USFS 2013). The formal scoping period ended after 45 days and received 155 public comments (USFS 2013). Two years later, the USFS published a Notice of Availability of the draft SEIS to the Federal Register (USFS 2012a). The USFS provided print and online information to nearby communities about the draft SEIS, the USACE Public Notice of Permit Application (USFS 2012b), and opportunities to provide comments at public meetings (USFS 2013).
The USFS complied with Executive Order 13175 through government-to-government consultation with Tribes (USFS 2011, 2013). Alaska National Interest Lands Conservation Act Section 810 requires the USFS to hold publicly available hearings to conduct an evaluation of the area's subsistence uses and needs on public lands following the notice of expansion. Under this process, the USFS held regional public hearings in two rural, predominantly Alaska Native communities (Hoonah and Angoon) to invite public testimony surrounding the tailings facility expansion (USFS 2013).
Through this period of soliciting public input, the USFS received over 700 comments about the expansion project (USFS 2013). Comments included support for Greens Creek mining activities, calls for reassessment of the SEIS to more strongly safeguard protection of the environment and cultural resources, concerns around insufficient scientific evidence, and support for specific alternatives over others (USFS 2013). Most comments in favor of greater environmental protections supported the no action alternative, which would minimize additional impact to nearby ecosystems by discontinuing mining operations at Greens Creek (USFS 2013).
Summary
Despite having the smallest physical expansion footprint (7 ha) among the five case studies, the tailings storage facility project underwent a comprehensive NEPA process with extensive public scrutiny. The location of Greens Creek Mine within a National Monument and its proximity to marine waters required compliance with numerous federal laws and extensive collaboration among state and federal agencies tasked with developing the SEIS. Nearly 900 public comments were received during the environmental review process. The high rate of public engagement required lead agencies to respond to a wide range of community concerns prior to the adoption of the final SEIS (USFS 2013).
Kensington case study
History, setting, and operations
An exclusive interest of Coeur Alaska, Inc. (hereafter, Coeur) since 1995, Kensington is located near Juneau, Alaska, in the Tongass National Forest near Berners Bay (Fig. 1; USFS 2020). Kensington is an underground operation using conventional mining methods for ore removal and processing to extract gold (Table 5). After the issuance of the original EIS in 1992 and prior to beginning operations, Coeur submitted two iterations of plans of operations to the USFS who then published corresponding SEISs in 1997 and 2004. The USFS Record of Decision issued in 2005 approved Coeur to begin operations at Kensington (USFS 2004).
Although Kensington was originally permitted in 2005, a lawsuit filed by local conservation groups delayed operations until 2010. The lawsuit objected to Coeur's plan to dispose of tailings in Lower Slate Lake, a natural, fish-bearing lake (SCOTUS 2009). The plaintiff's case argued that tailings are not considered fill material under Section 404 of the CWA (33 U.S.C. 1330) and therefore, a Section 404 permit would not be in accordance with the law. The case eventually reached the U.S. Supreme Court, which ruled that mining slurry did in fact constitute fill material and allowed the issuance of the permit (SCOTUS 2009). Coeur promptly began operations in 2010 and operated with few regulatory alterations, including an EA for a fuel depot in 2014 (USFS 2014) and an EA for surface exploration in 2018 (USFS 2018), both of which resulted in findings of no significant impact.
Key expansion issue
In October 2020, the USFS released a draft SEIS for an expansion project for Kensington's tailings dam and waste rock storage. This alteration to the original 2004 plan of operations proposed to raise the main tailings dam by 11 m (total height 38 m) and expand the waste storage capacity by nearly 4 million tons, therefore allowing operations to continue until at least 2033 (USFS 2020). The final SEIS was published in July 2021, and the Record of Decision was issued in February 2022 (USFS 2021, 2022). The selected alternative expanded mill throughput from 2000 to 3000 tons per day, total disturbance footprint from 138 to 171 ha, capacity of tailings storage from 4 to 8.5 million tons, and waste rock storage from 29 to 34 million tons. The additional disturbance included waste rock storage, additional roadways, and fish habitat enhancement (USEPA 2021; USFS 2021). This expansion sparked significant concern within the communities surrounding Juneau, effectively resurfacing the mine's litigious past nearly two decades later.
The involved federal agencies include the USFS, USEPA, and USACE (Tables 3 and 4). The USFS led the analysis for the SEIS within the NEPA framework and issued the Record of Decision since 69 ha of disturbance were located on USFS-managed land (USFS 2021, 2022). The USACE issued the required CWA Section 404 permit for the alteration of the tailings dam (USFS 2021). The raising of the tailings dam would increase the surface footprint of the tailings reservoir on Tongass National Forest lands, therefore requiring an environmental evaluation from the USFS (USFS 2021). While this thorough evaluation was required by NEPA due to a major change to the landscape, it was also informed by the previous lawsuit regarding Kensington's disposal of tailings in a natural, fish-bearing lake. The state and local agencies involved included the ADEC, ADNR, ADF&G, and CBJ (Tables 3 and 4). Tailings dam failure was the primary concern among social and ecological impacts. Dam stability and potential failure underpinned the majority of the ecological concerns, including soil quality, water quality, and fish and wildlife impacts, although water quality concerns were also prominent given the standards exceedances identified in downgradient surface waters (USFS 2021; see additional discussion of impacts in Text S1).
Public process, tribal engagement, and agency response
Public engagement for this expansion project came in two phases: during the scoping period and upon publication of the draft SEIS. The USFS received 33 public comments from individuals, organizations, and agencies during the 45-day scoping public comment period in 2019 (USFS 2020). The USFS held two public meetings in October 2019 in Juneau and Haines, registering 46 sign-ins total. The final SEIS mentioned Tribal engagement, naming specific Tribal associations, corporations, and other organizations that received the draft SEIS and were encouraged to comment. However, the final SEIS did not provide additional information about consultation efforts with Tribes beyond providing the named groups with scoping and draft documents (USFS 2021).
The USFS received 396 comments from agencies, municipalities, organizations, and individuals during the 66-day public comment period for the draft SEIS (USFS 2021). The more technical comments expressed concern about the adequacy of compliance with federal and state environmental laws such as NEPA, CWA, and Alaska National Interest Lands Conservation Act (Table 3; USFS 2021). Other comments questioned Coeur's previous compliance with the regulations stipulated within their permits, specifically regarding environmental issues such as water quality. Some comments urged the USFS to consider other solutions for tailings and waste rock storage, while others advocated for the environmentally preferred alternative (Table 1; USFS 2021). Some public comments advocated for specific mitigation efforts for groundwater contamination, potential adverse impacts on cultural resources, and essential fish habitat loss. In response, the USFS supplemented the existing analysis, in particular, adding discussion regarding the stability of the tailings dam (USFS 2021).
The geostability of the tailings dam area emerged from public comments as the most prominent concern. Commenters noted that the area was prone to landslides, especially as climate change alters environmental conditions in the area. The USFS refuted this concern by arguing that the area was topographically sound, a conclusion supported by their decades-long landslide inventory of the Tongass National Forest (USFS 2021). In a response to the final SEIS, the USEPA reiterated its concerns about catastrophic dam failure and urged the USFS to seek independent engineering reviews of the facility (USEPA 2021), a suggestion that the USFS accepted and included in its final Record of Decision (USFS 2022).
Summary
Compared to the 7 ha tailings storage expansion at nearby Greens Creek Mine, the Kensington expansion—which was also in National Forest lands, but not within a National Monument—was much greater in scope, including heightening the tailings dam, extending waste rock storage capacity, and increasing mill throughput rate. Relative to the other case studies, the Kensington SEIS contained a more extensive cumulative effects analysis, which considered the compounding impacts of the expansion with past, present, and potential future actions that overlap in space and time. The USFS considered the effect of climate change, particularly predicted warming and increased precipitation, on ecological and social concerns. Nearly 500 public comments were received during the environmental review process. Comments expressing concern about lack of environmental monitoring plans and dam inspections reflected public sentiment about being inadequately informed of legally mandated procedures and their outcomes. Although many commenters did not see their likely preferred outcome (i.e., halting the expansion), they successfully encouraged the USFS to consider the role that this expansion would play in the region, especially within the context of a changing climate.
Fort Knox case study
History, setting, and operations
Fort Knox is an open pit gold mine located in the Fairbanks North Star Borough of Alaska, roughly 40 km northeast of the city of Fairbanks (Fig. 1; FGMI 2023). Mining companies began exploring several subsurface claims from 1987 to 1991 (Kinross Gold Corporation 2018). Fairbanks Gold Mining, Inc. (FGMI) was established to operate the Fort Knox project and is now a subsidiary of Kinross Gold Corporation, a Canadian gold and silver mining company (Kinross Gold Corporation 2018; Table 5). Initial construction of the open pit mine and mill at Fort Knox started in 1995 with commercial production beginning in 1997 (Kinross Gold Corporation 2018). Ore is sourced from the Fort Knox pit as well as satellite pits at the Gil mine and the Manh Choh mine (FGMI 2023). These satellite pits are on mineral deposits that are disconnected from the original claim at Fort Knox, and ore from these pits is shipped—13 km from Gil and 367 km from Manh Choh—to the Fort Knox mill for processing (FGMI 2023).
The Fort Knox operations take place almost entirely on state lands, with some leased claims from private owners (Kinross Gold Corporation 2018). Therefore, most permitting decisions fall under the purview of state agencies such as the ADNR, ADEC, and ADF&G, as well as the USACE for federal permits. The permitting process for Fort Knox began in 1992 and triggered a NEPA review after application by FGMI for a Section 404 permit from the USACE pursuant to the CWA. Approval of that permit was contingent on the submission of an EA with public participation to the USACE. The EA was finalized in August 1993 (FGMI 1993).
Fort Knox is a notable case, because unlike the other large mines currently operating in Alaska, it was permitted and approved with an EA instead of an EIS. The assessment found that no significant impacts would result from the project and therefore no EIS needed to be conducted (FGMI 1993). Fort Knox is also unique in its use of satellite mines. These satellite mines—also permitted without an EIS—are large projects: 249 ha of land were disturbed at True North and 166 ha at Gil (FGMI 2012, 2021). The True North mine was the first such satellite mine and operated from 2001 to 2004 before closing and undergoing reclamation (FGMI 2012). The mines at the Gil and Manh Choh deposits began producing ore in 2021 and 2023, respectively, and remain active at the time of this study (FGMI 2023).
Key expansion issue
Media articles revealed a general concern with the increasing scale of operations at Fort Knox and its unique application of satellite mines. We evaluated the expansion and public engagement process for the 2002 pit expansion at the True North satellite mine. The True North project was originally permitted in January 2001. Ore was first hauled from the open pit mine to the Fort Knox mill in March 2001 (FGMI 2001). In December 2001, FGMI submitted a plan to the ADNR and USACE to further expand the operations at the mine to include more pits (FGMI 2001). The proposed plan would increase wetland and upland disturbance area by 78 and 159 ha, respectively (FGMI 2001). It would extend the life of the mine by up to 2 years and would increase the number of ore haul trucks as needed to account for the increased mining rate (FGMI 2001). Trucks would still adhere to the same noise limits and nighttime haulage rates (FGMI 2001). The amendments to the operations were considered “minor in the context of cumulative impacts” and the plan acknowledged that the impacts from the True North project generally were minor and as predicted (FGMI 2001, p. 1).
True North was on land managed by the ADNR and designated for minerals and public recreation (ADNR 2000). The ADNR issued a lease of the land to FGMI for the True North project, which allowed construction of the open pit mine and continued exploration of the area (ADNR 2000). The issuance of the lease was also conditioned on the approval of a Solid Waste Disposal Permit by the ADEC for the ore to be processed at the Fort Knox mill (ADNR 2000). Additionally, the expansion of the pit at True North needed to be approved by the ADNR and USACE.
The USACE first issued a CWA Section 404 permit to FGMI for their planned impacts to wetlands (FGMI 2012). This permit was initially issued for land clearing purposes associated with the exploration of mineral deposits at True North, but was later amended six times to include more roads and an open pit, which expanded the scope of the impacted wetlands (FGMI 2012). In July 2002, the final amendment was permitted, which allowed for further construction of roads and additional mine pits and is the expansion studied here (FGMI 2012). The initial permit allowed for 15 ha of wetlands to be disturbed, and the final cumulative total amount of disturbed wetlands after the amendments was 98 ha, but the final permit allowed for a maximum disturbance of up to 178 ha (FGMI 2012). Like the initial EA for Fort Knox, the EA prepared by the USACE found no major expected social or ecological concerns for the True North pit expansion project but acknowledged some short-term impacts to fish and wildlife habitat, air quality, noise, and light pollution (USACE 2002; see additional discussion of impacts in Text S1).
Public process, tribal engagement, and agency response
When operations of the True North mine were being amended to expand the size of the pit, there was a 30-day public comment period and 2 h long public meeting held in January 2002 in Fairbanks to solicit comments on FGMI's application for a CWA Section 404 permit for filling of wetlands (ADNR 2001). Review of permitting documents for both the initial EA of Fort Knox and the expansion to True North did not reveal any explicit Tribal consultation beyond the standard public comment process.
Comments were submitted to the USACE regarding FGMI's plan to fill 78 ha of wetlands and expand mining operations to more pits. Record of these comments was acquired through a Freedom of Information Act request (1 December 2024) and is summarized here. Many comments expressed support for the project, highlighting the economic benefits that the True North mine had brought and FGMI's positive track record. However, some residents of Cleary Summit and other nearby communities expressed concerns regarding light, noise, and fugitive dust from ore haul trucks. These concerns were echoed in many news articles found during the media review. One letter to the editor expressed dismay over Fort Knox's “piecemeal approach to permitting” and the “increased noise, light and air pollution” (Marshall 2018). These residents urged FGMI to limit ore haul to day time, but FGMI ultimately decided to keep ore haulage to the Fort Knox mill operating 24 h a day to keep down operating costs. Other comments also expressed a desire for a full EIS to be conducted, which never materialized.
The USACE ultimately amended the Section 404 permit for discharge into Murray Creek and allowed for the new wetland disturbance related to the pit expansion at True North. The ADNR also approved the expansion and FGMI received all necessary permits from both state and federal agencies. FGMI acknowledged concerns about more trucks crossing the highway and agreed to construct the Steese Highway Bridge and accepted the state's noise limits on the trucks (FGMI 2001). Public sentiment, overall, has been disparate throughout the life of Fort Knox and its satellite mines, with some members of the public expressing satisfaction with the mine operations and others concerned about local and regional impacts of the mine. This continues to the present day, where the Manh Choh satellite mine, now the furthest deposit—367 km away—to be processed at Fort Knox, has garnered significant public engagement.
Production at the True North mine ended in 2004, but the official reclamation and closure process was not initiated until 2009 (FGMI 2012). The goal of reclamation was to stabilize and revegetate closed areas to restore the land to a safe and productive state for wildlife habitat and recreation (FGMI 2012). By the summer of 2014, restoration efforts were completed and monitoring continued to ensure long-term stability of the environment (ADNR 2020). The Division of Mining, Land, & Water of the ADNR found that no contamination was present within the millsite lease area after conducting field inspections prior to approving the final release of the millsite lease in September 2020, therefore allowing the area to be open to the public (ADNR 2020). A joint press release from ADNR and ADEC commended the successful completion of the True North reclamation project, the only such reclamation for a mine of its size in Alaska, which reclaimed 249 ha of area directly affected by mining operations (Brune and Feige 2020).
Summary
The Fort Knox and True North expansion projects reveal a potential shortfall in the permitting and environmental review process. Despite extensive areas of new wetland and upland disturbance, the True North, Gil, and Manh Choh satellite mines were all able to move forward with production with cursory environmental review processes that were often limited in scope to the immediate activities allowed under the permits. While these assessments analyzed cumulative effects on the region, no EISs were conducted for any of the satellite mines. Industry appears to be examining the satellite mining approach as a common expansion strategy for future operations (Graham 2025).
The Fort Knox draft EA acknowledged the potential for other mines to develop in the region, but did not consider the possibility that these would be satellite mines that process their ore at Fort Knox (FGMI 1993). The current operations of Fort Knox reveal a different scale and form of project than what was initially permitted. Net disturbance area for Fort Knox was originally predicted to be about 1749 ha. The current disturbed area as of 2022 of Fort Knox and the Gil satellite mine (but not the recently added Manh Choh project) is 4077 ha (FGMI 2023). The rock at both Fort Knox and True North was not acid-generating, and operations were permitted under this assumption (FGMI 2012). Rock from the new Manh Choh deposit, however, is potentially acid-generating and, while being processed at Fort Knox, its tailings are expected to be stored separately (SRK Consulting 2022). Nevertheless, risk of acid mine drainage may become a concern and was not originally considered in the Fort Knox EA. The True North mine can be considered a successful operation followed by reclamation with no long-term adverse impacts, although it was a relatively simple operation compared to full-scale mines, with no tailings storage or mill infrastructure.
Pogo case study
History, setting, and operations
Pogo is an underground hardrock gold mine located about 61 km from Delta Junction in interior Alaska's Goodpaster River Valley (Fig. 1; Table 3). After gold deposits were confirmed in 1994, an EIS was initiated in 2000 and published in 2003 (USEPA 2003). Operations commenced in 2006 by Teck Cominco (Teck Cominco Limited 2006). The mine is currently owned by Australian-based company Northern Star Resources Limited (hereafter, Northern Star) on land managed by the ADNR (Northern Star Resources Limited 2018; USEPA 2003; Table 5). In the original EIS, the mine was proposed to operate for 11 years unless additional ore deposits were discovered (USEPA 2003).
The USEPA conducted the EIS for Teck Cominco's National Pollution Discharge Elimination System permit to discharge into the Goodpaster River. The USEPA subsequently issued the permit, but mine construction was briefly paused due to an administrative appeal of this permit by the Northern Alaska Environmental Center, a conservation organization (SitNews 2004). This was resolved within a few weeks after the mining corporation agreed to conduct additional monitoring of salmon in the Goodpaster River and convene a stakeholder group to review testing data (Dobbyn 2004). This appeal highlights the early history of engagement between the public, agencies, and the mine proponent. After the appeal was rescinded, construction continued (Dobbyn 2004). Since then, the mine operators have implemented expansion projects that have not triggered any additional public-facing EA or EIS statements. In 2020 and 2022, Northern Star led two expansion efforts for maintenance and extending the life of the mine, respectively (USACE 2020, 2022).
Key expansion issue
In contrast to the other four case studies, our media review did not pinpoint a key expansion issue for Pogo. The content of the articles (n = 231; Fig. 2) mainly described economic impacts. Since the media search did not highlight any expansion issues in the public eye, we focused on the two most recent expansions in 2020 and 2022. In 2020, Northern Star aimed to improve operational safety and maintain operational efficiency by expanding surface areas to access additional underground resources (USACE 2020). This project filled in 18 ha of wetlands and ponds with over 900 000 m3 of non-mineralized rock (USACE 2020). In 2022, Northern Star modified the 2020 project to expand the dry stack tailings facility and laydown areas to allow an additional 10 years of operations for the mine (USACE 2022). This project filled an additional 2 ha of wetlands with about 8000 m3 of non-mineralized rock (USACE 2022).
For each of these expansions, Northern Star submitted a Public Notice of Application for Permit (POA 1006-00211; hereafter, public notice) to the USACE for a Section 404 CWA permit and state water quality certification (USACE 2020, 2022). The USACE did not provide an EA for public comment. State permits and approvals may have been required for the expansions, but the state does not conduct EAs. The public notices stated that the work was not expected to impact cultural resources or endangered species (USACE 2020, 2022). Additionally, the work was not expected to impact essential fish habitat despite being in a known range of anadromous rearing Chinook salmon (Oncorhynchus tshawytscha) and spawning chum salmon (O. keta) (ADF&G Anadromous Waters Catalog: https://www.adfg.alaska.gov/sf/SARR/AWC/index.cfm; USACE 2020, 2022; see additional discussion of impacts in Text S1).
Public process, tribal engagement, and agency response
The sole mechanisms for public engagement for each expansion process were 30-day notices to provide written comments in response to the public notices. The 2020 public notice received three comments from federal and state agencies, while the 2022 public notice received three comments from a federal agency, state agency, and non-profit organization. All comments were neutral or positive in nature, such as information clarification requests or support of the expansion to help the economy. Although the comments were not publicly available online, we obtained them after contacting a USACE representative. The public notices also served as an invitation for Tribal participation in the process. Although the outcomes are not always public, there is no record of formal consultation or comments provided by Tribes.
Summary
Pogo was unique across the case studies as the only one not having a key expansion issue evident from media search results. In the 2020 and 2022 expansions, the public had opportunities to provide comments and input, which resulted in six public comments. These comments were not readily available through any public online sources. While the original EIS mentioned the possibility of expanding if more ore deposits were found, no timeline was provided for these potential expansions (USEPA 2003). Furthermore, cumulative effects were only described within the scope of each project, not for the projects in conjunction with the rest of the mine operations (USACE 2020, 2022). This case study further emphasizes potential gaps in evaluating cumulative effects of successive mining expansions on watersheds and surrounding communities.
Synthesis of key findings across case studies
Our case studies build upon the existing literature examining the legal and institutional complexity of assessing the impacts of mining operations (Baker and McLelland 2003; Tolvanen et al. 2019; Collison et al. 2022). In our comparative approach, we found wide variation in how permitting processes and public engagement were implemented for mine expansions. Most of this variation appeared to be based on different institutional (e.g., ACOE vs. USEPA or USFS) and jurisdictional (e.g., state- vs. federally managed land) contexts. Fort Knox and Pogo Mines, which occur exclusively on state and/or privately owned land, were able to begin and expand operations under less extensive regulatory and permitting processes than mines located within complex zones combining federal, state, and Tribal jurisdictions. Therefore, certain land ownership scenarios can result in siloing of mining expansion activities that do not require broader cumulative impact analyses.
The breadth and depth of public process varied greatly across case studies. We noted differences in the primary social–ecological concerns expressed in public comments (see case studies and Text S1); the comments revealed unique sets of concerns for each mine expansion, which likely resulted from the combination of differing local contexts between mines and differences in the nature of the expansion activities. Furthermore, we observed distinct approaches to cumulative effects analyses, even within the same agency, as well as challenges regarding public document access. Given the similar industrial scale of these hardrock mines, we had anticipated more consistency among the environmental analyses reviewed here. Greater consistency in the structure of EAs and public participation processes across mining projects may improve the public's general understanding of environmental impacts and promote more effective and equitable participation. In the Discussion, we further examine these findings in the context of the broader environmental impact assessment literature.
Discussion
Varied permitting processes, degree of engagement, and public concerns
The case studies highlight the context dependence of the permitting process in hardrock mines. Most, but not all, mines went through environmental review processes that included EISs at their onset and SEISs for expansions. Even so, the specific details and considerations included in each S/EIS differed, such as the inclusion or lack of cumulative effects analysis. Our case studies support previous research that has identified the inconsistency of how NEPA is applied–even within a single lead agency–as one limitation of the Act, suggesting a high degree of agency discretion (Stern et al. 2010; Fleischman et al. 2020; Ruple et al. 2022). For example, Ruple et al. (2022) found variation in NEPA analysis completion times across different geographic regions of USFS management.
Public engagement also varied widely between expansion projects. Some agencies solicited participation by extensively advertising the public comment periods online and through the radio, while others simply utilized Federal Register notices to inform the public of the comment periods. Based on the extensive records of public comments on their SEISs, there appeared to be more public scrutiny given to Red Dog, Greens Creek, and Kensington, whereas Fort Knox and Pogo received much fewer public comments on their EA and Public Notices, respectively. This likely stems from the greater degree of public engagement and analysis required for an EIS compared to an EA. Our case studies also highlight differences in geographic and institutional contexts and their influence on the NEPA process. For example, Greens Creek and Kensington are both located on federally managed land, whereas Pogo and Fort Knox—both of which received comparatively less scrutiny—are located primarily on state-managed land. While it is not located near a large population center, the Red Dog expansion also received hundreds of public comments, reflecting a complex discourse on the role of mining operations in rural communities globally, where the promise of economic development is often juxtaposed with environmental and human rights violations (e.g., Bebbington et al. 2018; Tolvanen et al. 2019).
In general, we found that SEIS processes had greater Tribal engagement than EA processes, but even within our three recent SEIS case studies, Tribal engagement was highly variable. Only the Red Dog Mine expansion (SEIS initiated in 2007) included Tribal governments as cooperating agencies, while both the Greens Creek and Kensington mine expansions (SEIS initiated in 2010 and 2020, respectively) consulted with Tribal governments but did not include them as cooperating agencies for the SEIS process. Assuming that the lead federal agency can provide support for important aspects of the planning process such as Tribal staff time, participating as a cooperating agency has the potential to promote more meaningful collaboration between Tribal and federal governments (Sloan 2007; Green and Cohn 2023).
For each mine, public comments cited several concerns. Although there were commonalities among mines—such as water quality and the health of fish and wildlife—each mine had unique primary concerns. In the case of Red Dog, many commenters were concerned about impacts on access to and health of subsistence resources. Comments on the Greens Creek SEIS expressed concern regarding the mine's further extension into the Admiralty Island National Monument. Kensington and Fort Knox commenters considered the possibility of pollution; for Kensington, potential tailings dam failure emerged as the main concern, whereas for Fort Knox, commenters worried about greater air and noise pollution from increased ore haul traffic. The unique primary concerns revealed through our analysis, paired with the heterogeneous permitting processes and resulting public engagement, illustrate the importance of local contexts within the federally mandated regulatory process for mine expansions in the US.
Cumulative effects analysis
An important component for considering the breadth and depth of environmental review processes is cumulative effects analysis, which reviews the foreseeable current and future impacts within and adjacent to a project area. Comparing these case studies highlights the variation in cumulative effects analyses for the expansion-related regulatory documents considered here. The Kensington analysis appeared to be the most robust among the case studies. Its SEIS more extensively addressed the cumulative effects of the proposed expansion within the contexts of climate change and environmental justice (USFS 2021). More recent NEPA processes have likely benefited from a growing body of best practices for integrating environmental justice considerations (e.g., Interagency Working Group 2019).
Although both the Red Dog and Greens Creek SEISs contained cumulative effects analyses, these played a less prominent role compared to impacts assessment for individual environmental concerns (USEPA 2009; USFS 2013). While not extensively analyzed in the original EA for Fort Knox, the EA for the True North expansion considered the development of satellite mines to have been reasonably foreseeable as cumulative effects; additionally, the True North analysis focused on positive impacts and deemed negative impacts to be minor (FGMI 1993; USACE 2002). While agencies may lack expertise or data to properly assess cumulative effects (Schultz 2012; Arnold et al. 2019), knowing the extent of the expansion impact and how it interacts with other social and ecological components of the geographical area is critical to properly assess risk. The frequency of expansions, the potential to use non-public facing methods (as seen in the Pogo case study), and the lack of consistency in implementation between and even within lead agencies could result in the full scope of the mines’ impacts being unknown or hidden from public knowledge (Stern and Mortimer 2009). This is especially true when compounding effects are not sufficiently analyzed (Smith 2006). Furthermore, there are no required regulatory methodologies that look at the cumulative effects of multiple mines in a shared geographical area. By narrowing the scope of analysis, an agency participating in the NEPA process may fail to achieve an accurate understanding of community and ecosystem health for supporting federal decision-making.
Challenges in accessibility of the public process
Locating relevant regulatory and permitting documents proved to be difficult and time-consuming, making case study approaches such as these difficult to implement. Agency websites had inconsistent document availability for each mine and files were often made inaccessible via broken or outdated links. These findings are consistent with a broader trend in access to environmental information (Lamdan 2016). Certain records were not readily available online and had to be acquired through a Freedom of Information Act request, which poses a barrier to public accessibility (LoMonte and Delgado 2023). Records and documents that were acquired tended to be long, dense, and full of unfamiliar regulatory language. Technical jargon can create complexity and limit understanding, even for agency employees themselves (Davenport et al. 2007). While the Council on Environmental Quality released A Citizen's Guide to NEPA (2021) that may help illuminate the environmental review process, including plain language summaries directly within regulatory documents may help distill information and improve public accessibility (Jones et al. 2012).
The NEPA process also places a large burden on members of the public to engage in a significant way. Public comment windows are often viewed as too short to develop a meaningful challenge to agency decisions (Ulibarri et al. 2022). Writing these comments, attending public meetings, and interpreting agency documents all require time and effort by members of the public. Stakeholders have often expressed frustration with agency decision-makers and the NEPA process in general (Teschner 2021). Making this process more accessible to the people and communities impacted by potential projects is essential for effective public engagement, particularly in remote or rural areas.
Role of NEPA and public involvement in mining expansions
In the U.S., NEPA continues to be the guiding framework for considering the potential environmental impacts of a significant federal action, and it continues to undergo refinements over time. For the public to truly understand the impacts of new and expanding mines and associated infrastructure and fully engage in the public process, agencies must prioritize transparency and accuracy within NEPA implementation. For example, the U.S. Department of the Interior elected not to permit Ambler Road in April 2024 due to the social and ecological impacts revealed during the NEPA process, such as habitat disruption and degradation for key subsistence species like salmon and caribou (Friedman 2024). This proposed industrial road would have stretched 340 km to facilitate access to copper and cobalt deposits in arctic Alaska (Friedman 2024). Consistent interpretation and application of NEPA by agencies is especially important for environmental impact assessment to remain robust in light of shifting government administrations and political priorities. Political shifts have led to vacillation in public and government support for development of other large mining projects in Alaska, most notably Pebble Mine (Wittenberg et al. 2020) and Donlin Mine (Ruskin 2024). Discretion in implementing the NEPA process and conducting environmental impact assessments at-large leads to wide variation in the quality of the analysis and the extent of the public process, as illustrated in the present study, therefore resulting in radically different environmental outcomes.
Conclusions
Our study provides valuable insights into the environmental impact assessment process for expansions of operating hardrock mines in Alaska, especially highlighting the varied permitting processes, public engagement approaches, assessment of cumulative impacts (or lack thereof), and challenges in accessing documentation. We acknowledge that this scope may limit the applicability of our findings to different mining or geographical contexts. For example, subsistence harvest practices are prevalent in Alaska, take place on managed public lands (Green et al. 2022; DOI Federal Subsistence Management Program: https://www.doi.gov/subsistence), and appear frequently as a topic in the public comments of our case studies. Mining operations in other states or countries may elicit differently motivated public engagement. In a similar vein, the social and ecological landscape of Alaska likely informs its regulatory landscape. For example, when compared to other states, Alaska is home to fewer endangered species, meaning that environmental impact analyses conducted as mandated by the influential Endangered Species Act may play a comparatively diminished role in EAs. Furthermore, our analysis of public engagement was limited to documentation of discourse that was available in the public record. This analysis could be further supported through surveys and/or interviews with residents and community members. Despite these limitations, our findings reflect broader issues related to mining development and offer a framework for future studies seeking to better understand the regulatory landscape of mine expansions and the role of public process.
Mining efforts will only increase with greater demand for new minerals, whether for green energy technologies in the case of metals like lithium or cobalt, or for luxury items in the case of silver and gold (Lezak et al. 2023). While there is evidence that the initial EIS process permitting large projects reduces overall environmental impacts (Ruple and Capone 2016), our case studies demonstrate that ongoing project expansions may undercut these protections. However, the NEPA implementation landscape is rapidly evolving and undergoing constant refinement. For example, the United States is currently considering the development of a “unified permitting portal” that would modernize document access, increase transparency, and promote the availability of information suitable for lay audiences (Council on Environmental Quality 2024). Continually evaluating the regulatory processes that govern environmentally destructive activities like mining is crucial to understanding and weighing the potential burdens and benefits, so that we may balance protecting natural resources while addressing societal demands.
Acknowledgements
For their contributions to our understanding of mining, the NEPA process, and much more, we thank B. Collison, J. DeMarchi, C. Frissell, S. O'Neal, and A. Westwood. We thank P. McGrath for invaluable feedback on this manuscript. M. Reece provided insightful comments on the Kensington and Greens Creek case studies. E. Keller provided guidance for creating systematic media searches. Thank you to the editor and anonymous peer reviewers for constructive comments that improved the manuscript. We thank the staff and faculty at the School of Marine and Environmental Affairs at the University of Washington for their support. EA, NH, JL, KAP, and JW are grateful for the generous support of donors who made this enriching research experience possible, from engaging in dialogues with experts to traversing the eldritch tunnels of active mining operations. Student support was provided by the SMEA Fellowship Fund, Ed Miles Memorial Student Support Fund, the Dayton “Lee” Alverson Fellowship, and the Usha and S. Rao Varanasi Endowed Fellowship in Environmental and Marine Stewardship.
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Volume 10 • 2025
Pages: 1 - 19
Editors: Paul Dufour and Victoria Metcalf
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Received: 26 August 2024
Accepted: 21 February 2025
Version of record online: 14 April 2025
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© 2025 The Author(s). This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author(s) and source are credited.
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Data generated or analyzed during this study are provided in full within the published article and its supplementary materials.
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Challenges in Environmental Impact Assessments for Hardrock Mine Expansions under NEPA
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Conceptualization: EA, NH, JL, KAP, JW, CJS, AHB
Data curation: EA, NH, JL, KAP, JW
Formal analysis: EA, NH, JL, KAP, JW
Investigation: EA, NH, JL, KAP, JW, CJS, AHB
Methodology: EA, NH, JL, KAP, JW, CJS, AHB
Project administration: EA, NH, JL, KAP, JW, CJS, AHB
Supervision: CJS, AHB
Visualization: JL, JW
Writing – original draft: EA, NH, JL, KAP, JW, CJS, AHB
Writing – review & editing: EA, NH, JL, KAP, JW, CJS, AHB
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The authors declare there are no competing interests.
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Elise Adams, Nika Hoffman, Jessica Lechtenberg, Katalin A. Plummer, Jack Winterhalter, Christopher J. Sergeant, and Anne H. Beaudreau. 2025. Excavating the regulatory process and risks posed by Alaska hardrock mine expansions. FACETS.
10: 1-19.
https://doi.org/10.1139/facets-2024-0175
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