Abandoned Uranium Mines

The uranium mining industry began in the U.S. in the 1940s primarily to produce uranium for weapons and later for nuclear fuel. Although there are about 4,000 mines with documented production, EPA, with information provided by other federal, state, and tribal agencies, has identified 15,000 mine locations with uranium occurrence in 14 western states. Most of those locations are found in Colorado, Utah, New Mexico, Arizona, and Wyoming, with about 75% of those on federal and tribal lands. The majority of these sites were conventional (open pit and underground) mines.

With the drop in market price of uranium beginning in the 1980s U.S. producers turned to in-situ leaching operations to extract uranium from ore. (In-situ leaching involves injecting solutions that will dissolve the uranium from the ore directly into the ground and then pumping out the uranium containing solution). By 2004, according to the Department of Energy's Energy Information Administration, there were only six uranium mines operating in the U.S. and half of those were in-situ operations. However, the number of operating mines of all kinds may increase as a result of higher world uranium prices and decreasing supply in the U.S.

Federal Agency Leads:

U.S. Nuclear Regulatory Commission

(Licensed uranium recovery facilities and mill tailings sites — 12 conventional uranium mills and four in situ leach (ISL) facilities)

U.S. Department of Energy

(Inactive tailings sites — currently 24)

U.S. Environmental Protection Agency

(All uranium sites not covered by NRC and DOE)

U.S. Land Management Agencies

Cleanup Efforts

To provide for the disposal, long-term stabilization, and control of uranium mill tailings in a safe and environmentally sound manner and to minimize or eliminate radiation health hazards to the public, Congress enacted the Uranium Mill Tailings Radiation Control Act of 1978 (UMTRCA). This Act established two programs to protect the public and the environment from uranium mill tailings. Under Title I, DOE was charged with completing surface reclamation at 24 inactive uranium mill tailings piles. Under Title II, cleanup is occurring at 16 uranium recovery facilities currently licensed by the NRC.

Beyond the authority of UMTRCA, EPA has authority to protect the public and the environment from exposures to both the hazardous and toxic characteristics of uranium mining overburden, which are classified as “Technologically Enhanced Naturally Occurring Radioactive Material” (TENORM). EPA frequently extends this authority to individual states, or federal land management agencies, which regulate the environmental impacts under clean water and clean air laws. These organizations also have a general authority to protect people and the environment from the adverse effects of mining activities.

EPA maintains a database that contains information on the approximately 15,000 mine locations with uranium.


In 1998, DOE testified to congress that it would cost approximately $2.3 billion (in 1998 dollar value) to clean up the uranium ore processing facilities nationwide under UMTRCA. Because there are other uranium mines and overburden sites not included in this estimate, the total cost of uranium site cleanup is expected to be much higher than this limited estimate.


Although several uranium mill tailings sites are on the Superfund National Priorities List (NPL), only two uranium mines are on the list: Midnite Mine, near Wellpinit, Washington, and the Fremont National Forest—White King/Lucky Lass Mines, Oregon. Both sites have progressed far enough in the Superfund process to have had a cleanup remedy selected in a Record of Decision. EPA has at least 30 sites on the NPL that have uranium contamination. These additional uranium sites are primarily processing facilities, tailings sites, and manufacturing sites.

Case Studies

Meter reading of radioactive tyuyamunite deposit

Pryor Mountain Uranium Sites, Montana

In 2006, the US Bureau of Land Management closured and reclaimed 10 abandoned uranium mines including: Marie, Robert’s Incline, Lisbon Point East, CM&M Pit, CM&M West, Dandy Southeast, Dandy Central, Dandy East, Dandy West Upper, and Dandy West Lower located in the Red Pryor Mountains of south central Montana. These mines posed physical safety as well as recreational exposure hazards prior to reclamation. BLM removed ore for reprocessing, re-graded waste rock/overburden piles, and closed mine entrances and fitted them with bat gates to maintain bat populations. Waste rock and overburden piles were uniquely re-graded to discourage recreational use on the piles.

Aerial Image of Midnite Mine, Washington State

Midnite Mine, Washington

Midnite Mine is an inactive former uranium mine in the Selkirk Mountains of eastern Washington. Located within the reservation of the Spokane Tribe of Indians, the mine was operated from 1955 until 1981. Two open pits, backfilled pits, and a number of waste rock piles and ore/protore stockpiles remain on site. In addition to elevated levels of radioactivity, heavy metals mobilized in acid mine drainage pose a potential threat to human health and the environment. The site drains to Blue Creek, which enters the Spokane Arm of Franklin D. Roosevelt Lake. Contaminated water emerging below the waste rock and ore piles is currently captured for treatment in an on-site treatment system. The final cleanup plan (Record of Decision, or ROD) for the site was issued September 29, 2006.

Resources >