Abandoned Hardrock Mines: Information on Number of Mines, Expenditures, and Factors That Limit Efforts to Address Hazards

The General Mining Act of 1872 allowed individuals to obtain exclusive rights to valuable hardrock mineral deposits on land belonging to the United States. Miners explored, mined, and processed valuable minerals, but many did not reclaim the land after their operations ended. Unsecured mine tunnels, toxic waste piles, and other hazards—known as mine features—are found at abandoned hardrock mines across federal and nonfederal lands. The Forest Service, BLM, National Park Service, EPA, and OSMRE—as well as state agencies—administer programs that identify and address hazardous features at abandoned hardrock mines. Addressing features could include, for example, sealing mine tunnels or treating contaminated water.

GAO was asked to provide information about abandoned hardrock mines. This report describes (1) what is known about the number of abandoned hardrock mines in the United States; (2) agency spending to address abandoned hardrock mines from fiscal years 2008 through 2017 and estimated future costs; and (3) factors that limit federal and state agencies' and stakeholders' efforts to address abandoned mines.

GAO obtained and summarized information from agency databases about the number of abandoned mines, features, and hazards as of 2019; summarized agency spending data from fiscal years 2008 through 2017, the most currently available; and interviewed federal and state agency officials and stakeholders, selected to provide diverse perspectives.

The U.S. Department of Agriculture's Forest Service, the Department of the Interior's Bureau of Land Management (BLM) and National Park Service, and the Environmental Protection Agency (EPA) identified at least 140,000 abandoned hardrock mine features, such as a tunnel, on lands under their jurisdictions. Of these, about 67,000 pose or may pose physical safety hazards—danger of injury or death—and about 22,500 pose or may pose environmental hazards—risks to human health or wildlife from long-term exposure to harmful substances. Agency officials also estimated there could be more than 390,000 abandoned hardrock mine features on federal land they have not captured in their databases, and agencies are developing more comprehensive information about these mines.

Forest Service, BLM, National Park Service, EPA, and Interior's Office of Surface Mining Reclamation and Enforcement (OSMRE) spent, on average, about $287 million annually to address physical safety and environmental hazards at abandoned hardrock mines from fiscal years 2008 through 2017, for a total of about $2.9 billion (see figure). Of this total, the agencies spent about 88 percent ($2.5 billion) addressing environmental hazards, and about $1 billion was reimbursed by private parties, such as former mine owners. Federal officials also estimated that it would cost billions more to address these mines in the future.

Nearly all of the federal and state agency officials and stakeholders GAO interviewed cited availability of resources and legal liability concerns as factors that limit efforts to address hazards at abandoned hardrock mines. Federal and state officials said their backlog of work is greater than what can be done with available staff and budgets, but they have taken steps to collaborate to help leverage resources. State officials and stakeholders, such as conservation groups, said they want to help address environmental hazards that they did not cause at abandoned hardrock mines. However, they generally do not do so because they are concerned about becoming legally responsible for the entire cost of addressing contamination at an abandoned mine if they attempt partial cleanup. EPA officials said they are considering new ways to encourage volunteer participation, in addition to existing administrative tools.

The General Mining Act of 1872 allowed individuals to stake claims and  obtain exclusive rights to gold, silver, copper, and other valuable hardrock  mineral deposits on land belonging to the United States. Until the federal  government established requirements in the 1970s for mine operators to  reclaim the land after their operations ceased—for example, by  regrading or reshaping the disturbed land—an operator could extract  hardrock minerals and abandon the mine without reclaiming it. With  populations growing in the western United States, abandoned mines that  once were remote are now much closer to population centers, according  to a U.S. government report.

Unsecured mine tunnels, decaying structures, pits, and other hazardous  features are found at many abandoned mines and can endanger the  physical safety of nearby residents and visitors to public lands.  Abandoned mines can also cause environmental degradation and  hazardous conditions that may pose risks to human health and the  environment, such as draining highly acidic water into soil and streams. In  many cases, the original mine operator is deceased or the mining  company has dissolved, leaving no private entity to pay for the cleanup.

Various government agencies and other entities are involved in  addressing abandoned hardrock mines. Specifically, the U.S. Department  of Agriculture’s (USDA) Forest Service and the Department of the  Interior’s Bureau of Land Management (BLM) and National Park Service  (Park Service) operate programs to address the physical safety and  environmental hazards found at abandoned hardrock mines on the  approximately 530 million acres of public lands they manage. In addition,  the Environmental Protection Agency (EPA) administers the Superfund  program, which addresses risks to human health and the environment  associated with abandoned hardrock mines on nonfederal lands, among  other things. Several states also operate programs that identify and  address physical safety and environmental hazards at abandoned  hardrock mines on both federal and nonfederal lands within their borders.  Interior’s Office of Surface Mining Reclamation and Enforcement  (OSMRE) awards grants to states and Indian tribes with abandoned  hardrock mine programs to conduct portions of this work. Some  stakeholders—including nongovernmental organizations, local citizen  groups, and mining companies—participate in projects to address  physical safety and environmental hazards at abandoned hardrock mines.

We previously reported information on abandoned hardrock mines,  including the number of mines and amount of federal agency spending to  address these mines. You asked us to provide updated information  about abandoned hardrock mines. This report describes (1) what is  known about the number of abandoned hardrock mines in the United  States; (2) federal and state agency expenditures to address abandoned hardrock mines from fiscal years 2008 through 2017, and what is known  about future costs to address these mines; and (3) factors that limit  federal and state agencies’ and stakeholders’ efforts to address  abandoned hardrock mines.

To describe what is known about the number of abandoned hardrock  mines in the United States, we obtained and summarized information  about abandoned hardrock mine sites and features—such as mine  tunnels, pits, and waste piles—that the Forest Service, BLM, the Park  Service, and EPA maintained in databases as of May 2019, the most  current at the time of our review. We also obtained information on the  agencies’ estimates of the number of additional abandoned hardrock  mine sites and features that exist but are not captured in their databases,  where applicable. Additionally, we collected information from officials with  state agencies that address abandoned hardrock mines in 13 western  states through semi-structured interviews about the number of  abandoned hardrock mine sites and features they identified as of May  2019, the most current at the time of our review. We selected these  states because our 2008 report and other federal and state agency  reports indicated that most of the abandoned hardrock mines in the  country are in these states. To assess the reliability of the federal and  state inventory information, we checked for missing data and errors,  reviewed documents about the data systems, and discussed the data and  any limitations with federal and state agency officials. We determined that  the data were sufficiently reliable to describe what these agencies know  about abandoned hardrock mines within their jurisdictions.

To describe federal and state expenditures and what is known about  future costs to address abandoned hardrock mines, we obtained and  summarized expenditure information from Forest Service, BLM, Park  Service, EPA, and OSMRE financial systems for fiscal years 2008  through 2017, the most current at the time of our review. We also  collected information through our semi-structured interviews with officials  from the 13 selected states about their expenditures of nonfederal and  federal funds during the same time period and summarized the  information. To assess the reliability of the information obtained from  these federal and state agencies, we tested the data for accuracy by  checking for errors, among other things. We discussed the expenditure  information, each agency’s data system, and any limitations with agency  officials. We determined that the data were sufficiently reliable for the  purpose of describing federal and state expenditures. We also reviewed  and summarized federal agency documents containing their estimates of  future costs to identify and address physical safety and environmental  hazards at abandoned hardrock mines that have not been addressed.

To identify factors that limit federal and state agencies’ and stakeholders’  efforts to address abandoned hardrock mines, we reviewed relevant  agency documents that describe limiting factors and interviewed Forest  Service, BLM, Park Service, EPA, and OSMRE headquarters officials.  We also interviewed officials from the regional or state offices of these  federal agencies who work in Colorado, Montana, and Nevada. We  selected these states for geographic diversity, higher numbers of  abandoned hardrock mines, and variation in the types of hazards posed  by abandoned mines in these states. For these three states, we also  interviewed officials with state agencies that address abandoned hardrock  mines. In addition, we interviewed a sample of stakeholders, selected to  provide perspectives from industry associations, nongovernmental  organizations, state agency associations, and individuals with long- standing involvement with abandoned hardrock mines. We identified and  selected these stakeholders based on our previous work, a review of  relevant literature, interviews with federal and state agency officials, and  recommendations from stakeholders. The sample of states and  stakeholders is not generalizable, but provides perspectives on factors  that limit efforts to address abandoned hardrock mines. In total, we  interviewed officials from 13 federal offices and three state offices and  representatives from 11 stakeholders, and we identified the factors that  they cited frequently. Appendix I contains a detailed description of our  scope and methodology.

We conducted this performance audit from June 2018 to March 2020 in  accordance with generally accepted government auditing standards.  Those standards require that we plan and perform the audit to obtain  sufficient, appropriate evidence to provide a reasonable basis for our  findings and conclusions based on our audit objectives. We believe that  the evidence obtained provides a reasonable basis for our findings based  on our audit objectives.

This section provides information about abandoned hardrock mines, sites,  and features; and federal and state agency roles in addressing  abandoned hardrock mines.

Abandoned Hardrock Mines, Sites, and Features

Federal and state agencies generally describe abandoned hardrock  mines in terms of mine sites, the individual features that comprise a site,  or both. However, these agencies do not all have a common definition for  what constitutes an abandoned hardrock mine or mine site, as we found  in 2008. The agencies generally agree on what constitutes an individual  feature—for example, a feature can be a mine opening (such as a tunnel,  pit, or vertical shaft), a structure, or a pile of discarded materials (known  as mine tailings or waste rock) that is left behind after ore is crushed and  the valuable minerals are extracted. They also generally agree that an  abandoned mine site can be comprised of only one feature (e.g., an  isolated mine shaft) or many features (e.g., an area with multiple entries,  shafts, open pits, mill buildings, and tailings piles). There is no  universally agreed-upon average number of features per site. Also, not all  federal and state agencies count both sites and features—some agencies  only count sites, some only count features, and some count both.

The individual features that make up a mine site may pose hazards to  physical safety and risks to human health and the environment.

Physical safety hazards. Abandoned hardrock mine features that pose  physical safety hazards generally present immediate danger of injury or  death. Examples of physical safety hazards include unstable mine tunnels that can collapse without warning; unmarked open mine shafts and deep pits that pose a danger to  individuals who may inadvertently drive off-road vehicles into them;  and deadly concentrations of gases, such as carbon monoxide and  methane, present inside some mines that can asphyxiate explorers.

To address physical safety hazards, federal and state agencies typically  focus on identifying and mitigating the risk from individual features. They  may safeguard these features by, for example, filling, capping, or gating  the abandoned mine openings with engineered structures. After a  dangerous feature is identified, an agency may post a warning sign or  erect a fence to temporarily limit access to the feature until the agency  can permanently close it. According to a 2008 Interior Inspector General  report, physical hazards require the least expertise to identify and  evaluate and the least funding to fix or mitigate.

Environmental hazards. Mine features can also contribute to  degradation of the environment and present short- and long-term risks to  human health. For this report, we refer to these collectively as  environmental hazards. People may be exposed to these hazards when  recreating or living near an abandoned mine. Examples of environmental  hazards include a mine tunnel that drains acidic water laden with heavy metals into a waste rock or tailings piles located along the banks or in the middle of  streams that release hazardous substances such as arsenic, lead,  and mercury into the water; and  tailings that have dispersed into a surrounding community’s soil,  exposing residents to harmful substances.

The extent of environmental hazards at abandoned mines can vary  widely, from sites that contain one draining tunnel and a few waste rock  piles to sites with extensive underground tunnel networks, many waste  rock piles, and miles of dispersed tailings. Some contaminated hardrock  mine sites are included on the National Priorities List, which includes  some of the most seriously contaminated sites that EPA identifies for  long-term cleanup. The work required to address environmental hazards  varies depending on the extent, type, and concentration of contaminants.  For example, agencies may take one or more of the following actions at a  site:  remove waste rock or tailings from streams; develop passive water treatment systems that allow water to flow out  of mines into treatment ponds; manage the waste on-site or transport it off-site for disposal; or establish active water treatment systems for the most contaminated  sites that require continuous long-term monitoring, among other  actions.

According to EPA documents, sites with environmental hazards can cost  hundreds of millions of dollars and take many years to address. For  example, as of July 2019, the actual costs at the 25 most expensive mine  and mineral processing sites ranged from $50 million to $583 million per  site, and EPA had been working on some of the sites for over 20 years.  Furthermore, agencies monitor remedies after completion to help ensure  that they are achieving the desired results.

Figure 1 depicts examples of physical safety and environmental hazards  found at abandoned hardrock mine sites and activities that could take  place to address them.

Land ownership at abandoned mine sites is often complicated. The  General Mining Act authorizes miners to patent, or purchase, the land  associated with their mining claims—thereby mined land often passed  from federal to private ownership. Partly because of this, many  abandoned mine sites are a patchwork of federal, private, and other  lands, and the ownership boundaries are not always clear. Agencies refer  to these sites as mixed ownership sites.

Federal and State Agency Roles in Addressing Abandoned Hardrock Mines

The Forest Service, BLM, the Park Service, EPA, and OSMRE, as well as  states with abandoned hardrock mines, administer programs that address  abandoned hardrock mines. Specifically, these federal and state  agencies collect information about abandoned hardrock mine sites and  features, and the associated hazards, on land under their jurisdictions.  These agencies also safeguard the physical safety hazards and clean up  the environmental hazards present at these mines. Agencies inventory  and address these mines based on their different authorizing statutes,  regulations, and missions.

The Forest Service is responsible for managing about 193 million acres of  national forests and grasslands throughout the United States. The Forest  Service’s Safety and Environmental Restoration program oversees the  agency’s work on abandoned hardrock mines. The Forest Service  distributed $15.9 million in appropriations to the Safety and Environmental  Restoration program in fiscal year 2019. USDA also distributed about  $6.9 million in fiscal year 2019 to the Forest Service to address  environmental hazards at several abandoned hardrock mines. USDA  seeks recovery of cleanup costs under the Comprehensive Environmental  Response, Compensation, and Liability Act of 1980, as amended  (CERCLA), from responsible parties, such as current and former owners  and operators of a contaminated site, to help reimburse costs at such  sites.

The Forest Service develops and maintains its information about  abandoned hardrock mines primarily at its regional, national forest, and  district offices. In general, the Forest Service tracks physical safety  hazards by feature and environmental hazards by mine site. As of  November 2019, the Forest Service did not have a national inventory of  abandoned hardrock mine features or sites and the physical safety  hazards they may pose. However, information about environmental  hazards at abandoned hardrock mine sites is contained in a database  maintained by USDA that tracks progress on all hazardous waste cleanup  projects funded by the department, including projects at abandoned  hardrock mines. Forest Service regional and national forest staff  inventory, assess, mitigate, and monitor the physical safety and  environmental hazards at abandoned hardrock mine sites on Forest  Service-managed land as part of their daily responsibilities.

BLM manages 245 million acres of public lands in the United States,  located primarily in the western states and Alaska. BLM’s Abandoned  Mine Lands program is aimed at protecting public safety and reducing  liabilities by eliminating or minimizing physical safety and environmental  hazards posed by abandoned mines, among other objectives. BLM’s  Hazardous Materials Management program also addresses  environmental hazards at all types of contaminated sites, including  abandoned hardrock mines. In fiscal year 2019, BLM received a total of  $38.5 million in appropriations for these programs. In addition, Interior  distributed $2.7 million to BLM in fiscal year 2019 from the Central  Hazardous Materials Fund—an Interior account that supports response  actions undertaken at contaminated sites pursuant to CERCLA—for work  at abandoned hardrock mines.

BLM maintains a national inventory of abandoned hardrock mines in its  Abandoned Mines and Site Cleanup Module database to help track  information about sites, features, and hazards. However, as of 2019, BLM  officials said the agency is shifting from tracking information by site, which  can be subject to interpretation, to primarily tracking and reporting  abandoned mine features. In addition to its abandoned mine database,  BLM submits a subset of information about its contaminated abandoned  mines to Interior for inclusion on the department’s list of contaminated  sites, the Environmental and Disposal Liabilities list. BLM state, district,  and field office staff inventory, assess, and mitigate the physical safety  and environmental hazards at abandoned hardrock mines on BLM- managed land while conducting their daily work.

The Park Service manages more than 85 million acres in 419 park units  across the country. The Park Service addresses abandoned hardrock  mines on this land through an abandoned mine safety program and an  environmental compliance and cleanup program. In fiscal year 2019, the  Park Service received $5 million in appropriations to address physical  safety hazards on abandoned mineral lands. Interior also distributed  $890,000 from the Central Hazardous Materials Fund to the Park Service  to address contaminated abandoned hardrock mine sites in fiscal year  2019. The Park Service recovers costs from responsible parties at  abandoned mine sites through CERCLA.

The Park Service maintains information about abandoned hardrock mine  sites and features in its Abandoned Mineral Lands Database. In 2013, the  Park Service completed a system-wide inventory and assessment project  to identify abandoned mines on lands it manages. In addition, the Park  Service submits information to Interior about contaminated abandoned  mine sites for inclusion on the Environmental and Disposal Liabilities list.  Park Service headquarters and regional offices may assist park units in  addressing hazards and preserving cultural resources and wildlife habitat  at abandoned hardrock mines on Park Service-managed land.

EPA administers the Superfund program, which was established under  CERCLA to address the threats that contaminated waste sites pose to  human health and the environment. As part of the Superfund program,  EPA oversees and conducts investigations and cleanup actions at a  variety of hardrock mine and mineral processing sites on private and  other nonfederal lands and mixed ownership sites. The Superfund  program operates on the principle that polluters are to pay for the  cleanups rather than passing on the costs to taxpayers. EPA may compel  parties statutorily responsible for contamination at sites to clean them up  or to reimburse EPA for its cleanup costs. Responsible parties at  abandoned hardrock mines could include current or former owners or  operators of a site; persons who arranged for disposal, treatment, or  transportation of hazardous substances; or the transporters of hazardous  substances. To address contaminated sites—including abandoned  mines—that do not have viable responsible parties, EPA uses funding  from appropriations to the Superfund program, which were approximately  $1.1 billion in fiscal year 2019.

EPA maintains information about abandoned hardrock mine and mineral  processing sites on nonfederal lands, including tribal lands, and mixed  ownership sites in its national database of contaminated sites, the  Superfund Enterprise Management System. EPA counts these mines and  processing facilities by site and not by individual mine feature. According  to EPA officials, many of the mine sites included in the database may  contain tens to hundreds of individual features. In addition, EPA does not  count sites that pose solely a physical safety hazard since they fall  outside of the Superfund program mission.

In addition, EPA and authorized states address certain abandoned  hardrock mines in accordance with the Clean Water Act. Specifically,  EPA and state agencies regulate discharges of pollutants to waters of the  United States at abandoned mine sites under the act, such as mine  tunnels draining contaminated water that exceeds water quality  standards. To comply with the act, an entity operating a cleanup project  involving a draining mine tunnel or other concentrated discharge source  must obtain a permit, under which the discharge must be treated or  managed to meet and maintain applicable water quality standards.

OSMRE’s Abandoned Mine Land program primarily focuses on  reclaiming and restoring land and water resources degraded by past coal  mining, but the program also supports reclamation at abandoned  hardrock mines. In accordance with the Surface Mining Control and  Reclamation Act of 1977, as amended, OSMRE can provide grants for  the reclamation of certain abandoned hardrock mines under limited  circumstances—in particular, after a state or Indian tribe certifies that it  has cleaned up its abandoned coal mine sites and the Secretary of the  Interior approves the certification. Absent such certification, OSMRE  can award these grants at the request of a state or Indian tribe where  necessary to protect the public health, safety, general welfare, and  property from extreme danger of adverse effects from the abandoned  hardrock mine, and the Secretary of the Interior grants the request. In  fiscal year 2019, OSMRE distributed a total of $310.5 million in grants to  states and tribes to address abandoned coal and non-coal mines.

OSMRE does not maintain an inventory of abandoned hardrock mines  since the Abandoned Mine Land program’s primary objective is to  address abandoned coal mines. States that receive grants from  OSMRE to address non-coal abandoned mines may maintain their own  inventories of abandoned hardrock mines. According to OSMRE budget documents, western states in particular often use OSMRE grants to  address physical safety hazards at high-priority abandoned hardrock  mines for which there is no other source of federal funding.

States identify and address physical safety and environmental hazards at  abandoned hardrock mines on state, county, and private lands within their  borders, often through state abandoned mine programs. States may also  work with federal agencies to identify and address these hazards on  federal land. Some state agencies manage or oversee cleanup activities  under CERCLA at abandoned hardrock mines. State agencies may  receive funds to support their work at abandoned hardrock mines from  nonfederal and federal sources, including state-appropriated funds,  responsible parties under CERCLA, and cooperative funding agreements  or grants from federal agencies. States with abandoned hardrock mines  generally maintain databases or inventories that identify the locations of  these mines and any associated hazards.

Federal and State Agencies Identified Several Hundred Thousand Abandoned Hardrock Mine Features, Over 100,000 of Which May Be Hazardous

As of May 2019, the Forest Service, BLM, the Park Service, and EPA  together identified in their databases at least 140,652 abandoned  hardrock mine features—of which over 60 percent are known to pose or  may pose physical safety or environmental hazards. Officials from  13 western states also identified from their state databases about  246,000 abandoned hardrock mine features on federal and nonfederal  lands within their states, including about 126,000 features that pose  physical safety or environmental hazards. Some state information  overlaps with federal agency information, but the extent of overlap is  unknown, according to state officials. Federal and state officials also  estimated that there likely are hundreds of thousands of additional  abandoned hardrock mine features that they have not yet captured in  their databases.

Federal Agencies Identified At Least 140,652 Abandoned Mine Features, about 89,000 of Which Pose or May Pose Physical Safety or Environmental Hazards

The Forest Service, BLM, the Park Service, and EPA identified in their  databases at least 140,652 abandoned hardrock mine features, as of  May 2019. Of this amount, BLM identified 103,029 features and the  Park Service identified 20,675 features. As previously noted, the Forest  Service and EPA track abandoned mines by site and not by features  associated with the sites; the Forest Service identified 16,375 sites and  EPA identified 573 sites. According to agency officials, many abandoned  hardrock mine sites contain more than one feature. Since there is no  agreed-upon average number of features per site, we counted the  minimum of one feature per Forest Service and EPA site for the purpose  of this analysis. As a result, the total number of features identified by  federal agencies likely is underestimated.

Of the 140,652 total features, about 89,000 features are known to pose or  may pose a physical safety or environmental hazard, according to  information in the federal agencies’ databases. Specifically, agencies  confirmed 7,802 features pose a hazard, of which 6,439 pose a  physical safety hazard and 1,363 pose an environmental hazard; and  identified 81,541 features with an unconfirmed hazard (whereby  agency staff had not assessed current conditions in person to confirm  the hazard), of which 60,279 may pose a physical safety hazard and  21,262 may pose an environmental hazard.

Table 1 shows information about abandoned hardrock mine features that  pose or may pose physical safety and environmental hazards, by agency.

However, agency officials said there could be approximately 393,000  more abandoned hardrock mine features on federal land that the  agencies identified on historic maps but have not captured in their  captured in a central database. In addition, BLM officials estimated  there are about 380,000 abandoned hardrock mine features on the land  BLM manages that are not captured in its abandoned mine database.  Park Service officials did not estimate a number of additional abandoned  mines that might be in Park Service units; they said they believe their  database is relatively comprehensive. Given the Forest Service and  BLM estimates of additional features not found in their databases, the  total number of estimated and identified abandoned hardrock mine  features on lands within Forest Service, BLM, Park Service, and EPA  jurisdiction is at least 533,652. Figure 2 depicts federal agency  information about the numbers of confirmed and unconfirmed physical  safety and environmental hazards on the lands under these agencies’  jurisdictions, in relation to the total estimated abandoned hardrock mine  features, as of May 2019.

To develop more comprehensive information about the total number of  abandoned hardrock mine features on the lands they manage, the Forest  Service and BLM are taking steps to improve their databases, including  capturing information about abandoned mines that are not currently in a  database. Specifically, Forest Service officials told us that they are  establishing a centralized geospatial database that will consolidate  information about abandoned hardrock mine features with physical safety  hazards that is currently maintained in regional and national forest offices.  They said they expect the new database will be populated in fiscal  year 2020 and that it will provide regional and headquarters managers  with better information about the extent of features with physical safety  hazards. In addition, BLM officials said that field staff have been  identifying and adding new features each year to its database, prioritizing  features located close to communities and recreational areas. BLM  officials said that they plan to update the database and communicate this  information to field staff in fiscal year 2020 to help ensure staff enter  information about new features into the database consistently.

Agencies in 13 States Identified about 246,000 Abandoned Mine Features in Their States, Including about 126,000 That Pose Physical Safety or Environmental Hazards

Officials with the 13 western states that we reviewed identified about  246,000 abandoned hardrock mine features on the federal, state, and  private lands within their state borders, as of May 2019. As with the  federal agencies, officials with five of the 13 states provided information  about total mine sites and not features; as a result, we counted the  minimum of one feature for each reported mine site for the purpose of our  analysis. Of the 246,000 total features in these states, state officials  estimated that about 115,000 features pose a physical safety hazard and  about 11,000 features pose environmental hazards.

State officials said that many of the features identified in their databases  were also likely to be found in the federal agencies’ databases, but the  extent of overlap is unknown. Specifically, the state officials’ estimates  include abandoned mine features on federal, state, and private land  because states may work on abandoned hardrock mines on both federal  and nonfederal lands. However, state officials are not always able to  quantify the number of mine features on federal land versus private or  state land. For example, some states’ inventories are based on  information from maps and databases that did not always include details  about land ownership boundaries, which are necessary to differentiate on  what lands the features are located. In addition, in instances in which the  states could identify the features that are on federal land, such as in Utah  and Nevada, state officials did not know how many of those features were  also captured in federal agency databases.

Similar to the federal agencies, officials with the 13 states estimated that  the actual number of abandoned hardrock mine features in their states is  higher than the information contained in their databases. State officials  noted that their inventories are incomplete, in part because they have not  conducted comprehensive, on-the-ground work to identify all the  abandoned mine features in their states. They primarily focus on  addressing the hazards they have already identified. Nevertheless, state  officials estimated that the number of abandoned hardrock mine features  in the 13 states could total more than 620,000. For example, California  officials we interviewed said field staff had identified more than 70,000  individual abandoned mine features in the state as of May 2019.  However, based on information from topographic maps, they estimated  that 274,000 total mine features exist statewide, with an undetermined  number of physical safety and environmental hazards.

The states’ estimates of abandoned hardrock mine features reflect the  different ways states collect information about abandoned hardrock  mines. For example, California and Nevada officials explained that they  count each individual abandoned mine feature in their states, whereas  Colorado and Utah officials said that they only collect information about  potentially hazardous features. Colorado officials estimated that there are  23,000 potentially hazardous abandoned hardrock mine features in the  state. However, if the state were to count all of the features in Colorado,  including shallow prospecting pits that are unlikely to pose a physical  safety hazard, the officials said the total estimate would be hundreds of  thousands of mine features. In addition, some states, including Idaho and  California, reported numbers of abandoned mine features that included  non-hardrock mines, such as sand and gravel pits, because their  abandoned mine programs address different types of abandoned mines.

Agencies Spent about $300 Million Annually from Fiscal Years 2008 through 2017 to Address Abandoned Hardrock Mines and Estimate Billions More in Future Costs

Federal agencies spent, on average, about $287 million annually  identifying, cleaning up, and monitoring abandoned hardrock mines, for a  total of about $2.9 billion, from fiscal years 2008 through 2017. The  Forest Service, BLM, the Park Service, EPA, and OSMRE primarily  worked in partnership with other federal and state agencies and some  nongovernmental stakeholders when addressing these mines, according  to federal officials. Officials from the 13 western states we reviewed  estimated spending an additional total of about $117 million in nonfederal  funds over the 10-year period, or an average of nearly $12 million  annually, to address abandoned hardrock mines within their states.  Federal agency officials said they estimated it would cost billions more to  address abandoned hardrock mines in the future.

Federal Agencies Spent about $287 Million Annually from Fiscal Years 2008 through 2017 to Address Abandoned Hardrock Mines, Collaborating with Other Agencies and Stakeholders

Federal agencies spent, on average, about $287 million annually, or a  total of about $2.9 billion, to identify, clean up, and monitor hazards at  abandoned hardrock mines from fiscal years 2008 through 2017. (See  fig. 3.) EPA spent 80 percent of the total federal expenditures—about  $2.3 billion—to address environmental hazards. Of the $2.9 billion in total  federal expenditures, approximately $1 billion was reimbursed by  responsible parties. Appendix II contains additional information about  Forest Service, BLM, Park Service, EPA, and OSMRE expenditures by  state.

The agencies used some expenditures to address physical safety  hazards but used most to address environmental hazards at abandoned  hardrock mines.

Physical safety hazards. The Forest Service, BLM, and the Park  Service spent a total of over $105 million from fiscal years 2008  through 2017 to address mine features that posed physical safety  hazards. According to officials with these agencies, this included filling  in holes and installing gates at tunnels and other mine openings to  allow bats, tortoises, and other wildlife to continue accessing  important habitat. (See fig. 4.) Officials also said that their  expenditures include funds provided to state agencies and others  through cooperative funding agreements for projects where the state  or other entity managed the work at the sites.

Environmental hazards. From fiscal years 2008 through 2017, the  Forest Service, BLM, the Park Service, and EPA spent a total of about  $2.5 billion to address environmental hazards at abandoned hardrock  mines. According to agency officials, work at these sites included  conducting initial site investigations, designing and implementing  remedies to address contamination, operating water treatment  facilities, and monitoring completed cleanup actions. The agencies  either managed this work themselves or provided funding through  cooperative agreements to state agencies or others to manage the  work. EPA spent about $2.3 billion at 394 sites, with about 40 percent  spent at five sites. Of EPA’s total expenditures, $983 million  (43 percent) was reimbursed by responsible parties. In addition, the  Forest Service, BLM, and the Park Service spent a total of about  $232 million to address various environmental hazards on lands they  manage, of which about $40 million was reimbursed by responsible  parties.

Further, OSMRE reported that 12 states and two Indian tribes spent  approximately $190 million in OSMRE grants to address abandoned  hardrock mines and other non-coal sites from fiscal years 2008 through  2017. OSMRE officials did not specify how much of the $190 million  was spent to address physical safety hazards versus environmental  hazards since the agency does not require states and tribes to report  such information. Table 2 shows federal agency expenditures by agency  and type of hazard.

Forest Service, BLM, and Park Service officials we interviewed said they  conducted most of their work to address physical safety and  environmental hazards at abandoned hardrock mines in collaboration with  state agencies, nonfederal stakeholders, and other federal agencies,  including EPA. These officials noted that it is important to partner with  state agencies and EPA because many of the abandoned mine sites are  of mixed ownership and the federal land management agencies generally  do not have authority to address mine features on nonfederal lands.

Federal agency officials said it is also helpful to pursue partnerships at  mixed ownership sites to leverage limited funding. For example, Forest  Service and BLM officials told us that they have partnered with Trout  Unlimited, a nongovernmental organization focused on conserving  freshwater fisheries and their watersheds, on projects to address  environmental hazards at mixed ownership abandoned hardrock mine  sites in several western states.

Examples of projects that federal agencies undertook with partners  include:

Flat Creek-Iron Mountain Mine and Mill, Montana. Since 2014, the  Forest Service has coordinated with EPA and the state of Montana to  address contamination from this abandoned mine and mill site on  private and Forest Service-managed lands upstream from the town of  Superior. Silver, lead, and other hardrock mining operations left mill  tailings piles that contaminated soil, groundwater, and surface water  in Flat Creek, which flows for 3.5 miles from the mine site through  Forest Service and private lands into the town. The local government  and individuals also used tailings as fill material in yards, roadways,  and other locations, including the high school track. The Forest  Service took the lead on the portion of the site on the land it manages,  and EPA and the state took the lead on various nonfederal portions of  the site. At the state’s request, in 2000, EPA started assessing and  cleaning up 79 residential and community properties in Superior; it  completed this effort in 2013. In 2017, the state removed mine tailings  from the private lands along Flat Creek with EPA oversight. As of  November 2019, the Forest Service has been working with Trout  Unlimited and the state to remove the mine tailings from the banks of  Flat Creek on Forest Service land. Trout Unlimited representatives  and Forest Service officials said they are also planning to reconstruct  the stream channel and floodplains and restore fisheries habitat in the  summer of 2020 after the tailings are removed.

Gold Butte National Monument, Nevada. In 2018, BLM and the  Nevada Division of Minerals worked with other federal, state, and  local agencies to address 40 features that posed physical safety  hazards within the historic Gold Butte Mining District in southern  Nevada. The abandoned mine features were within the BLM- managed Gold Butte National Monument, which was established in  2016. According to project documents, the anticipated increase in  recreation as a result of the monument designation prompted BLM  and the state to evaluate the area for potential physical safety  hazards. The 40 abandoned mine features included horizontal mine  tunnel openings and deep vertical openings. BLM and the Nevada  Division of Wildlife conducted cultural and wildlife surveys,  respectively, to help determine appropriate closure methods. The  state then filled the hazardous openings with foam and rock or  installed gates that provide access to bats and desert tortoises. The  local county government also contributed to the installation of the bat  gates.

Agencies in 13 States Estimated Spending a Total of about $117 Million of Nonfederal Funds from Fiscal Years 2008 through 2017 to Address Abandoned Hardrock Mines

Officials from the 13 states in our review estimated spending about  $117 million in total, or an average of nearly $12 million annually, of  nonfederal funds from fiscal years 2008 through 2017 to address physical  safety and environmental hazards at abandoned hardrock mines within  their states. Spending in three of the 13 states—California, Colorado,  and Idaho—represented over 86 percent of the total nonfederal  expenditures. Of the approximately $117 million, states spent about  $26 million addressing physical safety hazards and about $91 million  addressing environmental hazards. (See table 3.)

State officials said that the sources of nonfederal funds that the states  spent to address abandoned hardrock mines included (1) state-generated  funds and (2) funding from settlements with responsible parties.

State-generated funds. Officials from eight of the 13 states reported  that they expended revenue raised by the state government to work  on abandoned hardrock mines. Revenue sources include mine  license taxes and royalties on oil and gas, hardrock mines, and other  mineral extraction, and other sources such as the state general fund.  For example, officials from the California Department of Conservation  said the agency spent funds generated by state fees on active gold  and silver operations to address physical safety hazards at  abandoned mines on public lands. In addition, Colorado officials  said they spent funds from a state severance tax collected on oil and  gas, coal, metallic minerals, and other mineral production to address  physical safety and environmental hazards.

Settlements with responsible parties. Officials from five of the 13  states reported that they spent funds received from settlements with  responsible parties to either conduct cleanup actions or oversee the  responsible parties’ work to address environmental hazards. For  example, from fiscal years 2008 through 2017, the state of New  Mexico spent over $3.8 million that it had collected from responsible  parties at two abandoned hardrock mine sites, according to state  documents. Nevada and Washington officials said that their agencies’  expenditures to address environmental hazards during the 10-year  period were entirely funded by collections from responsible parties.

State officials we interviewed said they spent these nonfederal funds to  address abandoned hardrock mines located primarily on private, county,  state, or other nonfederal lands, including at mixed ownership sites.  Officials from two of the 13 states (Colorado and Nevada) said they also  spent state-generated funding to address hazards on federal land.  Officials from the Nevada Division of Minerals’ abandoned mine program  said that they generally spend about 80 to 90 percent of the program’s  nonfederal funding addressing physical safety hazards on federal land.  These officials explained that fees from unpatented mining claims on  federal land are the division’s main funding source and, therefore, the  state spends most of this funding to address hazards on federal land.

Officials with the 13 states also told us that, in addition to spending about  $117 million in nonfederal funds over the 10 years, states also spent  more than $440 million they received from federal agencies, primarily  through grants and cooperative agreements, during this period. Officials  with seven states reported that they receive significantly more federal  funds than nonfederal funds to work on abandoned hardrock mines and  that federal funding is critical to addressing hazards at these mines.

Federal Agencies Estimated Billions More Would Be Needed to Address Abandoned Hardrock Mine Hazards

The Forest Service, BLM, the Park Service, and EPA estimated that their  future costs to inventory and address physical safety and environmental  hazards at abandoned hardrock mines would be in the billions of  dollars. Each agency has generated some information about estimated  future costs using a variety of methods and covering a range of activities.  Given the level of uncertainty associated with the estimates, they likely  understate the amounts that will be needed to comprehensively inventory  and address these hazards.

The Forest Service and BLM estimated that it could cost over $650 million  to finish inventorying abandoned hardrock mines on lands they manage.  Specifically, Forest Service information indicated it could cost about  $147 million to complete the agency’s inventory, which includes  identifying potential environmental hazards at 15,247 sites as well as the  locations and conditions at approximately 13,000 sites not currently  captured in a database. In addition, BLM officials estimated that it would  cost about $510 million to complete the agency’s inventory of abandoned  hardrock mines. This estimate includes about $130 million to evaluate  approximately 66,000 features identified as posing an unconfirmed  physical safety or environmental hazard. It also includes another  $380 million to confirm the locations and presence of hazards at the  approximately 380,000 additional features that may be on BLM-managed  land but are not in its database.

The Park Service and EPA did not provide estimates for future inventory  work. Park Service officials said they have not estimated costs for  additional inventory work because they believe that their inventory is  largely comprehensive. EPA officials explained that the agency does not  manage lands so they do not work to identify the existence of  contaminated abandoned mines. Rather, EPA relies on external sources,  such as state agencies and local governments, to alert it of potentially  contaminated sites on nonfederal lands that may need attention.

Estimated Costs to Address Physical Safety Hazards

BLM and the Park Service estimated it could cost nearly $5 billion to  address the physical safety hazards at abandoned hardrock mines on the  lands they manage, and the Forest Service has not estimated this  amount. Specifically, BLM estimated it could cost about $4.7 billion to fill  in, gate, or otherwise address the nearly 65,000 features it has identified  with confirmed and unconfirmed physical safety hazards and the  estimated 380,000 additional features that are not yet included in the  agency’s database. Park Service officials said they estimated that it  would cost about $86 million to address the physical safety hazards at the  abandoned hardrock mines identified in the agency’s database. These  officials said that they plan to revise this estimate once they have better  information about the actual costs to close the features where they are  currently working.

The Forest Service and EPA did not have estimates for addressing  physical safety hazards. The Forest Service has not comprehensively  estimated these costs, although the individual forests identify priority  projects for spending each year, according to agency officials. EPA has  not separately estimated costs to address physical safety hazards since  those costs are included in its estimates to address environmental  hazards.

Estimated Costs to Address Environmental Hazards

The Forest Service, BLM, the Park Service, and EPA have partly  estimated costs to address environmental hazards at abandoned  hardrock mines. Agency officials said that they do not have  comprehensive estimates, in part because they have not yet selected the  cleanup remedy at numerous sites—information they need to develop  detailed estimates—nor have they identified all of the contaminated sites  that will need to be addressed. The officials explained that a remedy to  address an abandoned mine site with one waste rock pile (e.g., removing  the pile from a creek and constructing a repository for it) is different from  a remedy needed to address a site with perpetually draining mine tunnels,  which could include operating and maintaining water treatment systems  over the long term. As a result, the costs of cleanup remedies can vary  from hundreds of thousands to hundreds of millions of dollars per site.  Estimates of future costs to address environmental hazards at abandoned  hardrock mines and what the estimates included varied by agency:

Forest Service. Forest Service and USDA officials said that they  estimated in 2014 that it could cost about $6 billion to address  environmental hazards at 6,600 abandoned hardrock mine sites on  Forest Service-managed land. This estimate includes costs to  assess the extent of contamination, search for responsible parties,  design and implement an action to remove a small waste rock or  tailings pile, and monitor and maintain each site for 30 years after the  cleanup is complete. According to the estimate, costs to maintain the  completed sites make up half of the $6 billion in estimated future  costs. These officials also said they assumed that all 6,600 sites are  relatively simple and not complex with more extensive contamination.  In developing this estimate, the Forest Service did not assume that  responsible parties would cover any of these costs.

BLM. BLM estimated a portion of the costs associated with  addressing environmental hazards at abandoned hardrock mines on  BLM-managed land, since BLM officials said there are too many  unknowns and unique circumstances at each feature to  comprehensively estimate total costs. These officials said the agency  has estimated costs for some sites with confirmed environmental  hazards in accordance with Interior’s environmental liabilities reporting  guidance. Specifically, as of June 2019, BLM estimated that future  costs to address environmental hazards at 105 abandoned hardrock  mine sites on BLM-managed land range from $61 million to about  $265 million. Interior and BLM officials explained that these costs do  not represent all future costs needed to clean up these sites. Instead,  the range includes the future costs that the agency determines are  reasonably estimable at the time for these sites. In some cases, these  costs are limited to the cost of conducting a study if the agency has  not selected a cleanup remedy. As a result, officials said they expect  that BLM’s estimate of total future costs will increase once the agency  selects the cleanup remedies and estimates their costs. Officials also  said they have not estimated future costs for sites where the agency  has not determined the type or extent of the contamination or where  BLM is not likely to fund the cleanup, for example, because a  responsible party may pay for it.

Park Service. Similar to BLM, Park Service officials estimated the  future costs associated with addressing environmental hazards at  50 contaminated abandoned hardrock mines, based on Interior’s  guidance. As of June 2019, the Park Service estimated that these  future costs range from $21 million to $35 million, exclusive of any  reimbursements from responsible parties. The Park Service did not  estimate the future costs to address 19 additional sites that the  agency identified as posing environmental hazards because either  work at these sites is in the early stages, the agency was unable to  estimate costs, or the Park Service is not likely to fund the cleanup,  according to Park Service and Interior officials.

EPA. EPA officials told us that they do not have a comprehensive  estimate of costs to clean up hardrock mines. Specifically, officials  said EPA tracks planned obligations to be incurred for sites where the  agency anticipates taking action within the next 3 years to help  support its budget development process. As of fiscal year 2018, EPA  identified about $519 million in planned obligations for 115 hardrock  mine or mineral processing sites. EPA officials said the planned  obligations do not necessarily reflect the total estimated costs  remaining at a site because the agency typically requires its regions to  report known planned obligations for 3 years, or longer, if available.  According to EPA data, future costs to address hardrock mines likely  will exceed these obligations. For example, EPA did not report  planned obligations for 423 mine and mineral processing sites where  the agency has not completed site assessment work or selected a  cleanup remedy. According to EPA officials, they generally do not  plan obligations for future cleanup work while conducting an  assessment. However, they said that if an assessment reveals a need  for a time-sensitive response at a site, the agency may fund it. EPA  officials also told us that they expect responsible parties to pay a  portion of the future costs associated with these sites, but that amount  is unknown.

Federal and State Agencies and Stakeholders Cited Availability of Resources and Legal Liability Concerns as Factors That Limit Efforts to Address Abandoned Hardrock Mines Federal and State Officials Cited Availability of Resources as a Limiting Factor

Federal agency officials, state officials from three selected states  (Colorado, Montana, and Nevada), and stakeholders cited availability of  resources and legal liability concerns as factors that limit efforts to  identify, clean up, and monitor hazards at abandoned hardrock mines.  Federal and state officials said their backlog of work on abandoned mines  is greater than current staff and budget levels. In addition, state agency  officials and other stakeholders we interviewed, such as nongovernmental  organizations and mining companies, have limited their participation in  projects to address environmental hazards at abandoned mines because  of concerns about their potential legal liability under CERCLA and the  Clean Water Act.

All of the officials we interviewed from the Forest Service, BLM, the Park  Service, and EPA, as well as from Colorado, Montana, and Nevada, cited  availability of resources as a factor that limits their efforts to identify and  address the physical safety and environmental hazards at abandoned  hardrock mines. Representatives from state associations and  nongovernmental organizations we interviewed also cited this factor as  limiting federal and state efforts. Federal and state officials said that their  backlog of work on these mines far exceeds their current staff and budget  levels. For example, BLM officials estimated that with the agency’s  current abandoned mine budget and staff resources, it could take up to  500 years to confirm the presence of physical safety or environmental  hazards at the approximately 66,000 features in its database and the  estimated 380,000 features not yet captured in its database.

Officials from Colorado and Montana and representatives from a state  association noted that these two states regularly receive reclamation  funding from OSMRE to address abandoned coal mines in their states.  As a result of having access to such funds, five states, including Montana  and Wyoming, as well as three tribes have certified that they have  addressed all of their known priority abandoned coal mines. These  officials also noted that there is not a similar or consistent source of  funding for states to address hazards at abandoned hardrock mines. In  Nevada, although state-collected mining fees contribute to addressing  safety hazards at abandoned hardrock mines, state officials said they do  not have a consistent source of funding to address environmental  hazards. As a result, Nevada officials explained that they tend to work  primarily on mines where there is a viable responsible party to fund the  cleanup. However, one official said that most of the approximately  190 abandoned hardrock mine sites in the state that pose or may pose  environmental hazards do not have a viable responsible party.

Federal and state agency officials described several steps they have  taken to work more efficiently within existing limited resources. For  example, federal agency officials said they prioritize proposed projects to  address abandoned mines that pose the highest safety and  environmental risks. In addition, federal officials explained that they have  established several formal mechanisms for national and local  collaboration to facilitate leveraging resources. For instance, federal and state officials working in Colorado said they formed a working group in  2010 to jointly identify and prioritize watersheds that have been  contaminated by abandoned hardrock mines. The agencies work  collaboratively to evaluate the extent of contamination in each watershed,  leading to a more holistic approach to addressing contamination,  according to EPA and Colorado state officials. Regional Forest Service  officials we interviewed who also work outside of Colorado said the group  is a national model for collaboration and efficient use of resources.

Forest Service, BLM, Park Service, EPA, and state officials also said that  they work to leverage federal and state resources by searching for  responsible parties to contribute funding to their efforts at abandoned  hardrock mines. However, officials told us that identifying such parties is  difficult and can be resource intensive given the length of time that has  elapsed since the mines were abandoned and the lack of a clear chain of  custody and land ownership boundaries at mine sites.

State Officials and Stakeholders Cited Legal Liability Concerns as a Limiting Factor

All of the state officials and nearly all of the stakeholders from  nongovernmental organizations, state associations, and industry we  interviewed cited concerns over legal liability—that is, being held legally  responsible for addressing environmental contamination—as a factor that  limits efforts to address certain abandoned hardrock mine hazards on  nonfederal land. Specifically, liability concerns can prevent third parties— entities who offer assistance in addressing environmental hazards that  they did not create and are not legally required to clean up—from taking  actions to help address such hazards that are on private land and on  nonfederal portions of mixed ownership sites. These parties are often  referred to as Good Samaritans and may include state agencies,  nongovernmental organizations, local governments, private landowners,  and mining companies, among others.

Federal and state officials and stakeholders we interviewed said that  Good Samaritans have avoided taking certain cleanup actions—in  particular, addressing mine tunnels that perpetually drain highly  contaminated water—at abandoned hardrock mines because they are  concerned about potentially being held legally responsible under  CERCLA and the Clean Water Act. Specifically, a Good Samaritan  undertaking cleanup actions at an abandoned hardrock mine might  become a responsible party under CERCLA and thereby would be  responsible for the entire cost of cleaning up the site. As a result,  representatives from an industry association and a nongovernmental  organization told us that while they are interested in addressing  contamination on private land in the West, they generally have not done  so, in part because of concerns about becoming responsible under  CERCLA for cleaning up all of the contamination present at the site.

In addition, a Good Samaritan undertaking cleanup actions to address  draining mine tunnels may be required to do so in accordance with a  discharge permit under the Clean Water Act. Complying with such a  permit requires that the cleanup meet and maintain water quality  standards, which can be expensive and may require perpetual water  treatment. State officials and stakeholders explained that meeting and  maintaining such standards at certain mines is difficult because of  naturally occurring heavy metals and continual drainage from the mines.  They said they are interested in undertaking smaller-scale projects to  address mine tunnel drainage that may significantly improve water quality  and aquatic habitat but would not fully meet water quality standards.  However, Colorado and Montana state officials and various stakeholders  said they generally decide not to undertake such projects, even if they  could make incremental improvements, because of the risk of being held  responsible for meeting and maintaining water quality standards in  perpetuity.

To encourage nongovernmental organizations, other stakeholders, and  states to participate in abandoned hardrock mine projects at mixed  ownership sites and on other private land, EPA developed administrative  tools aimed at limiting Good Samaritans’ CERCLA and Clean Water Act  liability. In 2007, EPA developed guidance for issuing “comfort/status  letters” to Good Samaritans willing to perform cleanup work under EPA  oversight and for entering into settlement agreements—legally  enforceable documents signed by EPA and a Good Samaritan that  include a federal covenant not to sue under CERCLA in exchange for  cleanup work. In 2012, EPA also issued guidance stating that, as a  general matter, the agency would not require a Good Samaritan to obtain  a Clean Water Act discharge permit if they successfully complete a  cleanup action under a comfort/status letter or settlement agreement with  EPA.

Good Samaritans have participated in some projects at abandoned  hardrock mines using EPA’s administrative tools. As of January 2020,  EPA had issued four comfort letters and entered into three settlement  agreements, generally to address hazards at sites that did not require a  Clean Water Act permit. Some state officials and stakeholders we  interviewed said they have not pursued using EPA’s administrative tools  because, in part, these tools do not sufficiently alleviate liability under the  Clean Water Act. For example, they explained that the tools and guidance  provide reassurance that EPA may not sue the Good Samaritan but do  not ensure that certain outside parties will not sue to require they meet  water quality standards.

State officials and stakeholders we spoke with said that they believe that  resolving the concerns over CERCLA and Clean Water Act liability may  require federal legislation. However, other stakeholders expressed  concerns that legislative changes, such as amending CERCLA or the  Clean Water Act, could inadvertently result in weakening the existing  environmental protections in these and other laws or could limit the ability  of outside parties to enforce their provisions. Since 1999, several bills  have been introduced that would have responded to liability concerns but  as of December 2019, none had been enacted. State officials and  stakeholders have been involved in efforts to draft legislation that would  address liability concerns, but the interested parties have disagreed about  the specific provisions to include.

While federal agency officials did not cite liability concerns as a factor that  limits their agencies’ efforts to address abandoned hardrock mines on  lands under their jurisdictions, Forest Service, BLM, and EPA officials  concurred that legal liability concerns deter Good Samaritans from  participating in projects with federal agencies at mixed ownership sites.  Federal officials explained that, unlike Good Samaritans, the abandoned  hardrock mines the federal agencies address are under their jurisdiction  and the agencies are already responsible for meeting the requirements of  CERCLA and other applicable laws. However, federal agency officials  have observed the effects of Good Samaritan legal liability concerns on  projects. For example, Forest Service officials in Colorado said that  potential partners have expressed interest in addressing contamination  on the private land portions of mixed ownership sites but declined once  they learned they would be subject to liability under CERCLA.

In the absence of legislative changes, EPA officials said they are looking  for new ways to encourage Good Samaritan participation in abandoned  hardrock mine projects. For example, they are working to update and  refine the agency’s administrative tools and identify new solutions to  better address Good Samaritans’ concerns. They are also looking to  encourage Good Samaritan participation in more projects that would not  require a Clean Water Act permit, such as moving mine tailings piles  away from streams.

We provided a draft of this report to the Department of Agriculture, the  Department of the Interior, and EPA for their review and comment. The  Forest Service Audit Liaison provided comments by email, stating that the  Forest Service generally agreed with the report. USDA and EPA provided  technical comments, which we incorporated as appropriate. Interior told  us they had no comments.

As agreed with your office, unless you publicly announce the contents of  this report earlier, we plan no further distribution until 30 days from the  report date. At that time, we will send copies of this report to the  appropriate congressional committees, the Secretaries of Agriculture and  the Interior, the Administrator of EPA, and other interested parties. In  addition, the report will be available at no charge on the GAO website at  http://www.gao.gov.

If you or your staff have any questions about this report, please contact  me at (202) 512-3841 or fennella@gao.gov. Contact points for our Offices  of Congressional Relations and Public Affairs may be found on the last  page of this report. GAO staff who made key contributions to this report  are listed in appendix III.

Appendix I: Objectives, Scope, and Methodology

This report describes (1) what is known about the number of abandoned  hardrock mines in the United States; (2) federal and state agency  expenditures to address abandoned hardrock mines from fiscal years  2008 through 2017, and what is known about future costs to address  these mines; and (3) factors that limit federal and state agencies’ and  stakeholders’ efforts to address abandoned hardrock mines.

To address these objectives, we reviewed our previous work on  abandoned hardrock mines, including a March 2008 report in which we  summarized information about the number of abandoned hardrock mines  in the United States and the amount of federal spending on these mines  from fiscal years 1998 through 2007. We also reviewed federal agency  reports to identify the federal agencies that track numbers of abandoned  hardrock mines, conduct work to address hazards at these mines, or fund  projects to address these hazards. We identified the U.S. Department of  Agriculture’s (USDA) Forest Service; the Department of the Interior’s  Bureau of Land Management (BLM), National Park Service (Park  Service), and Office of Surface Mining Reclamation and Enforcement  (OSMRE); and the Environmental Protection Agency (EPA) to include in  our review. We reviewed agency documents detailing these agencies’  cleanup efforts and abandoned hardrock mine programs.

We also selected 13 western states to include in our review: Alaska,  Arizona, California, Colorado, Idaho, Montana, Nevada, New Mexico,  Oregon, South Dakota, Utah, Washington, and Wyoming. We selected  these states because our March 2008 report and other federal and state  agency reports indicated that most of the abandoned hardrock mines are  in these states. We conducted two site visits to abandoned hardrock  mines in Colorado in February 2019. We selected sites in Colorado  because they provided opportunities to observe examples of physical  safety and environmental hazards on federal and nonfederal lands. We  visited sites with physical safety hazards that BLM and the state had  addressed on BLM and county lands. We also visited a National Priorities  List site where EPA and the state were addressing environmental  hazards on private land.

To describe what is known about the number of abandoned hardrock  mines in the United States, we obtained and summarized information  about abandoned hardrock mine features and sites—including the  number of features and sites that pose confirmed and unconfirmed  physical safety and environmental hazards—that the Forest Service,  BLM, the Park Service, and EPA maintained in databases as of  May 2019, the most current at the time of our review. Specifically:  the Forest Service provided information about abandoned hardrock  mine sites from USDA’s National Environmental Accomplishment  Tracking system;

BLM provided information about abandoned hardrock mine features  from the Abandoned Mines and Site Cleanup Module;  the Park Service provided information about abandoned hardrock  mine sites and features from the Abandoned Mineral Lands Data  Entry and Edit database and from Interior’s Environmental and  Disposal Liabilities list; and

EPA provided information about hardrock mining and mineral  processing sites from its Superfund Enterprise Management System.

In addition, we obtained information on the agencies’ estimates of the  number of additional abandoned hardrock mine sites or features that are  not captured in their databases, where applicable.

We assessed the reliability of the agencies’ databases by testing the data  for accuracy by cross-referencing with relevant data sets and checking for  missing data and errors. We also reviewed agency documents about the  databases and our previous related work regarding the use of these  data. We also interviewed headquarters officials from each agency and  discussed the data and any limitations. We determined that the  information in the agencies’ databases about the number of abandoned  hardrock mines was sufficiently reliable to summarize in our report.

We calculated the agencies’ total number of abandoned hardrock mines  in terms of the number of features. According to agency officials, many abandoned hardrock mine sites contain more than one feature, but there  is no agreed-upon average number of features per site. Since the Forest  Service and EPA reported information only by mine site, we counted the  minimum of one feature per site in our calculations. As a result, the total  number of features likely is underestimated.

Further, we collected information about the number of abandoned  hardrock mines in the 13 western states through semi-structured  interviews with state officials. For each state, we interviewed officials with  the relevant state agencies that address abandoned hardrock mines  through, for example, a dedicated abandoned mine program or a broader  program focused on addressing environmental hazards. In each  interview, we asked the officials to provide information about the numbers  of abandoned hardrock mine sites they identified in their state, features  that posed a hazard to public health and safety, and features that caused  environmental degradation as of the time of our review. We provided the  states with a common definition of abandoned mine site and feature.  However, officials with five states provided information only for  abandoned mine sites and not features. For those states, we counted the  minimum of one feature per site to calculate the states’ total number of  abandoned hardrock mine features. As a result, the states’ total number  of features likely is underestimated. We assessed the reliability of the  states’ information by reviewing documents about the data systems,  checking for missing data and errors, and discussing the data and their  sources with state officials, including any limitations. We determined that  the data were sufficiently reliable to describe what the state agencies  know about abandoned hardrock mines within their jurisdictions.

To describe federal agency expenditures to address abandoned hardrock  mines from fiscal years 2008 through 2017, we summarized expenditure  information from the Forest Service, BLM, the Park Service, EPA, and  OSMRE for this time period, the most recent 10 years of information  available at the time of our review. Specifically, we collected information  about total expenditures to address abandoned hardrock mines,  expenditures to address physical safety hazards, expenditures to address  environmental hazards, and expenditures of collections from responsible  parties under the Comprehensive Environmental Response,  Compensation, and Liability Act of 1980 (CERCLA), as applicable. We  assessed the reliability of the agencies’ information by testing the data for  accuracy and completeness by checking for missing data and errors. We  also reviewed our previous related work regarding the use of the  information and interviewed agency officials involved with collecting or  analyzing the information. We determined that the information obtained  from the agencies was sufficiently reliable for our descriptive purposes.  Additional details on agency-specific information we used follows:

Forest Service. The Forest Service provided expenditure information  for fiscal years 2008 through 2017 for its Abandoned Mine Land and  Environmental Compliance and Protection programs from its  Foundation Financial Information System. The Forest Service also  provided information from this system about expenditures of  reimbursements from responsible parties. USDA provided information  about the Forest Service’s expenditures from the department’s  Hazardous Materials Management Account for fiscal years 2008  through 2017 from the Financial Management Modernization Initiative  system.

BLM. BLM provided expenditure information from Interior’s Financial  Business Management System for fiscal years 2009 through 2017.  BLM’s budget office provided expenditure information for fiscal year  2008 since information prior to fiscal year 2009 is not included in  Interior’s current financial system. BLM provided information about  abandoned hardrock mine expenditures from relevant subactivity  codes, including Abandoned Mine Lands, Hazardous Materials  Management, American Recovery and Reinvestment Act-Abandoned  Mine Land projects, and Central Hazardous Materials Fund, among  others.

Park Service. The Park Service provided expenditure information  from Interior’s Financial Business Management System and the Park  Service’s Project Management Information System and Administrative  Financial Systems 3 and 4 for fiscal years 2008 through 2017 for its  Abandoned Mine Lands program and the Contaminants Cleanup  Branch. The Park Service also provided information from Interior’s  system about expenditures of reimbursements from responsible  parties.

OSMRE. OSMRE provided expenditure information from Interior’s  Financial Business Management System for fiscal years 2008 through  2017 from its non-coal account, which includes spending for projects  to address abandoned hardrock mines, non-hardrock abandoned  mines, and other eligible projects. To further narrow the non-coal  account expenditures to spending on abandoned hardrock mines, we  reviewed information for projects that states completed during the  10-year period and eliminated expenditures that were clearly identified  for non-hardrock-related projects. We also compared the expenditure  information from OSMRE with expenditure information we obtained  during our semi-structured interviews with officials from six state  agencies that reported spending OSMRE grants specifically on  hardrock abandoned mines—Alaska, Colorado, New Mexico,  Montana, Utah, and Wyoming. We determined that Alaska’s and  Colorado’s reported expenditures were more specific to abandoned  hardrock mines than the information OSMRE provided for those  states. As a result, we used Alaska’s and Colorado’s information to  report expenditures for those states and used OSMRE’s information  to report expenditures for all other states. OSMRE officials agreed  with this approach.

EPA. EPA provided information about the Superfund program’s  expenditures at mine and mineral processing sites from the Integrated  Financial Management System for fiscal years 2008 through 2011 and  the Compass Financial System for fiscal years 2012 through 2017.  EPA provided expenditures from its (1) Superfund appropriation  accounts, (2) special accounts through which EPA receives resources  from settlements with responsible parties for EPA to conduct site- specific work, and (3) state cost-share accounts, through which states  contribute 10 percent of costs for EPA’s Superfund-financed remedial  actions. EPA also reported expenditures of funds provided by other  federal agencies; we excluded these expenditures from our reporting  of EPA’s spending to avoid potential double counting.

Further, we obtained information through our semi-structured interviews  with officials from the 13 selected states about their expenditures of  nonfederal and federal funds at abandoned hardrock mines for state fiscal  years 2008 through 2017. We obtained and summarized information on  total expenditures to address abandoned hardrock mines, expenditures to  address physical safety hazards, and expenditures to address  environmental degradation. We also obtained information about the  sources of the agencies’ funding, such as collections from responsible  parties. The states provided expenditure information by state fiscal year  and not federal fiscal year because their financial systems are organized  by state fiscal year.

We assessed the reliability of the states’ expenditure information by  testing for missing data and errors, reviewing documents, and discussing  the information and any limitations with state agency officials. Three  states were unable to provide expenditure information specific to  abandoned hardrock mines for the entire 10-year period. Therefore, we  discussed and agreed with each of these states how they could provide  information that most closely responded to our request—for example, by  providing information for the years that were available—and we are  reporting the state agencies’ total expenditures as estimates. We  determined that the data were sufficiently reliable to describe an estimate  of how much in nonfederal and federal funds the state agencies spent to  address abandoned hardrock mines.

We are reporting both federal and state agency expenditures in nominal  dollars. We are doing so for several reasons, including that there was a  relatively low rate of inflation from fiscal year 2008 through 2017 (about  1.5 percent per year, on average); not all states reported annual  expenditures that could be adjusted for inflation; and federal and state  agencies reported annual expenditures differently, with federal agencies  reporting by federal fiscal year and state agencies reporting by state fiscal  year.

To describe what is known about future costs to address abandoned  hardrock mines, we reviewed and summarized documentation of the  federal agencies’ most recently available estimates of costs to inventory  additional abandoned hardrock mine features and to address physical  safety and environmental hazards that have not been addressed. We  discussed these estimates, and the assumptions used to create the  estimates, with relevant agency officials. We describe the estimates and  their underlying assumptions in the report.

To identify factors that limit federal and state agencies’ and stakeholders’  efforts to address abandoned hardrock mines, we reviewed relevant  agency documents and independent reports that describe limiting factors.  We interviewed federal agency officials, state agency officials, and  stakeholders. More specifically, we interviewed Forest Service, BLM,  Park Service, EPA, OSMRE, and Interior headquarters officials and  officials from these agencies’ regional or state-based offices who work in  Colorado, Montana, and Nevada. We also interviewed officials with the  relevant state agencies that address abandoned hardrock mines in these  three states. We selected these states for geographic diversity, higher  numbers of abandoned hardrock mines, and variation in the types of  hazards posed by abandoned hardrock mines in these states. The  sample of states is not generalizable, and the results of our work do not  apply to all states where abandoned hardrock mines are located, but  provide illustrative examples.

In addition, we obtained perspectives from stakeholders that have  participated in or expressed interest in participating in projects to address  abandoned hardrock mines. We interviewed a sample of stakeholders,  selected to provide perspectives from industry associations,  nongovernmental organizations, state agency associations, and  individuals with long-standing involvement in issues related to addressing  abandoned hardrock mines. We identified and selected these  stakeholders based on our previous work, including the stakeholders we  interviewed for our March 2008 report; a review of relevant literature,  including written testimony statements and a summary of proceedings  from a 2018 conference on abandoned hardrock mines; interviews with  federal and state agency officials; and recommendations from  stakeholders. Our sample of stakeholders is not generalizable to all  stakeholders involved with abandoned hardrock mines, but provides  perspectives on factors that limit efforts to address abandoned hardrock  mines.

In total, we obtained responses from officials with 13 federal agency  offices, including six headquarters offices and seven regional or state- based offices; officials with three states; and representatives of  11 stakeholder organizations, including three state associations that  represent states with abandoned mine programs, two nonprofit  conservation organizations, two mining industry associations, one mining  company, and three individuals with long-standing involvement in  abandoned hardrock mine policy. In our discussions, officials and  representatives with each entity identified the factors that limit their or  others’ efforts to address abandoned hardrock mines. We reviewed the  responses and identified the factors that officials and stakeholders in  each group (i.e., federal agencies, state agencies, and stakeholders)  frequently mentioned. Two factors arose frequently both within and  across the groups—we describe these factors in our report.

We conducted this performance audit from June 2018 to March 2020 in  accordance with generally accepted government auditing standards.  Those standards require that we plan and perform the audit to obtain  sufficient, appropriate evidence to provide a reasonable basis for our  findings and conclusions based on our audit objectives. We believe that  the evidence obtained provides a reasonable basis for our findings based  on our audit objectives.

Appendix II: Federal Expenditures to Address Abandoned Hardrock Mines, by State, Fiscal Years 2008 through 2017

Table 4 includes expenditures to address abandoned hardrock mines for  the Bureau of Land Management, Environmental Protection Agency,  Forest Service, Office of Surface Mining Reclamation and Enforcement,  and National Park Service.

Appendix III: GAO Contact and Staff Acknowledgments

In addition to the contact named above, Elizabeth Erdmann (Assistant  Director), Leslie Kaas Pollock (Analyst-in-Charge), Matthew Elmer,  William Gerard, Anne Rhodes-Kline, Sheryl Stein, Sara Sullivan, and  Rajneesh Verma made key contributions to this report.

Until the 1970s, mine operators could mine for valuable hardrock minerals—i.e., gold or copper—then abandon the land. On lands they oversee, federal agencies identified about 140,000 remnants of these hardrock mines, including unsecured tunnels and toxic waste piles. Hundreds of thousands more likely exist.

Remedies include sealing tunnels and treating contaminated water to address safety and environmental hazards. But this can come with a hefty price tag.

Most federal and state officials said they had trouble identifying and eliminating hazards at abandoned mines because doing so would cost millions and create potential liability issues.