Uranium mining in the United States declined drastically in the 1980s, but has revived since 2001 due to higher uranium prices. The average spot price of uranium oxide (U3O8) increased from $7.92 per pound in 2001 to $39.48 per pound in 2006.
The late 1940s and early 1950s saw a boom in uranium mining in the western U.S., spurred by the fortunes made by prospectors such as Charlie Steen. The United States was the world's leading producer of uranium from 1953 until 1980, when annual U.S. production peaked at 16,810 metric tons U3O8. Until the early 1980s, there were active uranium mines in Arizona, Colorado, New Mexico, South Dakota, Texas, Utah, Washington, and Wyoming.
Price declines in the late 1970s and early 1980s forced the closure of numerous mines. Most uranium ore in the United States comes from deposits in sandstone, which tend to be of lower grade than those of Australia and Canada. Because of the lower grade, many uranium deposits in the United States became uneconomic when the price of uranium declined sharply in the late 1970s. By 2001, there were only three operating uranium mines (all in-situ leaching operations) in the United States. Annual production reached a low of 779 metric tons of uranium oxide in 2003, but then more than doubled in three years to 1672 metric tons in 2006, from 10 mines. The U.S. DOE's Energy Information Administration reported that 90% of U.S. uranium production in 2006 came from in-situ leaching.
Uranium is used primarily for nuclear power. In 2001 the United States had 104 operating nuclear power plants generating 20% of the nation's electrical power supply. Although the United States had the most nuclear power plants of any country, it generated a much lower percentage of electricity from nuclear power than did France (76% from nuclear) or Japan (34% from nuclear). In 2001 the United States mined only 5% of the uranium consumed by its nuclear power plants. The remainder was imported, principally from Russia (50%), Canada, and Australia.
Although uranium production has declined to low levels, the United States has the fourth-largest uranium resource in the world, behind Australia, Canada, and Kazakhstan. United States uranium reserves are strongly dependent on price. At $30 per pound U3O8, reserves are estimated to be 265 million pounds (120,000 metric tons); however, at a price of $50 per pound, reserves are an estimated 890 million pounds (400,000 metric tons). Rising uranium prices since 2001 have increased interest in uranium mining in Arizona, Colorado, Texas and Utah. The states with the largest known uranium ore reserves (not counting byproduct uranium from phosphate) are (in order) Wyoming, New Mexico, and Colorado.
Uranium in Alabama is found in the Coosa Block of the Northern Alabama Piedmont. Metamorphic uranium occurrences have been found in the Higgins Ferry Group in Coosa and Clay Counties. Some exploration has been done, but no economic deposits have been found to date.
Uranium was discovered at the Ross-Adams deposit in 1955 by an airborne gamma radiation survey. The deposit is at Bokan Mountain on Prince of Wales Island. The principal ore mineral was uranothorite, which occurred in veinlets in granite. Accessory minerals were primarily hematite and calcite, with lesser amounts of fluorite, pyrite, galena, quartz, and rare earth minerals. The first mining was done in 1957, when ore was removed from an open pit 25 to 75 feet (23 m) wide, 370 feet (110 m) long, and 30 feet (9.1 m) deep. Additional mining took place in 1959-1964 and 1970-1971  A total of 1.3 million pounds of uranium were produced, with all of the milling taking place in Washington and Utah. There is a firm looking at the potential of reopening the mine.
Uranium mining in Arizona has taken place since 1918. Prior to the uranium boom of the late 1940s, uranium in Arizona was a byproduct of vanadium mining of the mineral carnotite. There are currently no producing uranium mines in Arizona.
Uranium was discovered in 1954 in the Sierra Nevada of Kern County, along the Kern River about 30 miles (50 km) northeast of Bakersfield. Two mines, the Kergon mine and the Miracle mine, made small shipments in 1954 and 1955. Uranium occurs as uraninite and autunite in shear zones in granodiorite. Accessory minerals include fluorite and the molybdenum minerals ilsemanite and jordisite.
The first uranium identified in the USA was pitchblende from the Wood gold mine at Central City, Colorado in 1871. Uranium mining in southwest Colorado goes back to 1898. The Uravan district of Colorado and Utah supplied about half the world's radium from 1910 to 1922, and vanadium and uranium were byproducts. The only currently active uranium mine in the state is the Sunday mine near Uravan, Colorado, owned by Denison Mines.
The central-Florida phosphorite deposits are considered to contain the largest known uranium resource (one million metric tons of uranium oxide) in North America (but note that resources are not the same as ore reserves). Uranium has been produced as a byproduct of phosphate mining and the production of phosphoric acid fertilizer. The uranium is contained in the phosphate minerals francolite, crandallite, millisite, wavellite, and vivianite, found in Miocene and Pliocene sediments of the Bone Valley Formation. The average uranium content is 0.009%. However, because the recovery process costs an estimated $22 to $54 per pound of U3O8, more than the price of uranium from the 1980s through the early 2000s, uranium has not been recovered from Florida phosphate since 1998. Because of the high price of uranium since 2003, uranium recovery may be reactivated.
From 1955 to 1960, uranium was extracted from placer black sand deposits derived from the Idaho Batholith in southwest Idaho. The deposits were mined for uranium, thorium, and rare earths. Uranium and thorium were in the monazite grains; rare earths were in columbite and euxenite. Production was 365,000 pounds (165 metric tons) of U3O8.
Uranium was mined at the Stanley district in Custer County, Idaho from 1957 to 1962. Deposits occur as veins in granite of the Cretaceous Idaho Batholith, and in strataform deposits in possibly Paleocene arkosic conglomerates and sandstones between the underlying Idaho Batholith and overlying Challis Volcanic Group (Eocene). The USGS has estimated production to be less than 170,000 pounds (78 metric tons) of U3O8.
The only uranium mine in Nebraska has been the Crow Butte mine, operated by Cameco. The mine is five miles (8 km) southeast of Crawford in Dawes County, western Nebraska. The roll-front deposit in the Oligocene Chadron formation was discovered in 1980 by Wyoming Fuel Co. Mining began in 1991. The uranium is being mined by in-situ leaching.
The uranium deposit of the Apex mine (also called the Rundberg mine or the Early Day mine) was discovered in 1953, three miles south of Austin, Nevada, in Lander County. The mine produced 45 metric tons of U3O8 from 1954 until the mine was closed in 1966. Uranium occurs as autunite and meta-autunite in fractured Cambrian quartzite and argillite, adjacent to Jurassic quartz monzonite.
New Mexico was a significant uranium producer since the discovery of uranium by Navajo sheepherder Paddy Martinez in 1950. Uranium in New Mexico is almost all in the Grants mineral belt, along the south margin of the San Juan Basin in McKinley and Cibola counties, in the northwest part of the state. No mining has been done since 2002, even though the state has second-largest known uranium ore reserves in the U.S.
Some lignite coal in southwest North Dakota contains economic quantities of uranium. From 1965 to 1967 Union Carbide operated a mill near Belfield in Stark County to burn uraniferous lignite and extract uranium from the ash. The plant produced about 150 metric tons of U3O8 before shutting down.
A small amount of uranium ore was mined in the mid-1950s from a surface exposure at Cement in Caddo County. The uranium occurred as carnotite and tyuyamunite in fracture fillings in the Rush Springs Sandstone over the Cement anticline, where the sandstone is bleached. The mined area was 150 feet (46 m) long, 3 to 5 feet (0.9 to 1.5 m) wide, and extended 3 to 5 feet (0.9 to 1.5 m) below ground surface.
Uranium was discovered in Oregon in 1955, near Lakeview in Lake County. The White King mine and the Lucky Lass mine shipped uranium from 1955 until 1965. At the White King mine, uranium was mined by both underground and open-pit methods from a low-temperature hydrothermal deposit in Pliocene volcanic rocks, associated with opal, realgar, stibnite, cinnabar, and pyrite. At the Lucky Lass mine, the uranium without the associated minerals was mined from an open pit.
A minor amount of uranium was mined in 1960 from a deposit at Bear Creek Butte in Crook County. The uranium was present as autunite at the contact between a rhyolite dike and tuffs of the Oligocene-Miocene John Day Formation.
The uranium mineral autunite was reported in 1874 near the town of Mauch Chunk (present-day Jim Thorpe) in Carbon County, eastern Pennsylvania. A small amount of test mining was done in 1953 at the Mount Pisgah deposit near Jim Thorpe. The uranium at the Mount Pisgah deposit is primarily in an unidentified black mineral in pods and rolls in the basal conglomerate of the Mauch Chunk Formation (Mississippian). Also present are the secondary uranium and uranium-vanadium minerals carnotite, tyuyamunite, liebigite, uranophane, and betauranophane.
Uranium was discovered near Edgemont, South Dakota in 1951, quickly followed by mining. The uranium occurs in Cretaceous sandstones of the Inyan Kara group, where it outcrops along the southern edge of the Black Hills in Fall River County, South Dakota. Minerals in unoxidized sandstone are uraninite and coffinite; minerals in oxidized zones include carnotite and tyuyamunite.
An airborne gamma radiation survey flown by the US Atomic Energy Commission in 1954 discovered high radiation readings over the Cave Hills area in Harding County, in the northwest corner of the state. High winds blew the reconnaissance flight off their planned survey route over the Slim Buttes twenty miles southeast of the North Cave Hills. Claims were immediately staked over uranium-bearing lignite beds in the area. The lignite was strip-mined, probably starting that same year, and continuing until the mines closed in 1964.
No uranium is currently mined in South Dakota.
In January 2007 Powertech Uranium Corporation received a state permit to drill boreholes to evaluate their Dewey-Burdock project, in Custer and Fall River counties northwest of Edgemont. Previous work at the property in the early 1980s defined a resource of 10 million pounds (4500 metric tons) of uranium, of which 5 million pounds (2300 metric tons) were estimated recoverable by conventional underground mining. Powertech hopes to bring the property into production as an in-situ leaching mine in 2009.
A campaign has been underway to halt any effort to mine uranium in the Black Hills because of its effect on Native American and wildlife populations, as well as the effects of mining on the water table and local ranchers. Indigenous leaders and anti-nuclear activists began organizing around this issue in the 1970s and there are still efforts underway to prevent mining on native lands.
The uranium district of south Texas was discovered by accident in 1954 by an airborne gamma radiation survey looking for petroleum deposits. The coastal plain had previously been regarded as highly unfavorable for uranium deposits. The uranium occurs in roll-front type deposits in sandstones of Eocene, Oligocene and Miocene age. The deposits are distributed along about 200 miles (320 km) of coastal plain, from Panna Maria in the north, south into Mexico. Uranium production began in 1958, from open-pit and in situ leach mines.
Uranium production stopped in 1999, but restarted in 2004. By 2006, three mines were active: Kingsville Dome in Kleberg County, the Vasquez mine in Duval County, and the Alta Mesa mine in Brooks County. 2007 production was 1.34 million pounds (607 metric tons) of U3O8.
Energy Metals Corp. is applying for permits to begin mining the La Palangana deposit in Duval County; the company hopes to begin mining in 2008.
Mining of uranium-vanadium ore in southeast Utah goes back to the late 1800s. All of Utah’s numerous uranium mines closed prior to 2000, because of low prices. In late 2006, Denison Mines reopened the Pandora mine in the La Sal mining district of southeastern Utah.
Marline Uranium Corp. announced in July 1982 that it had discovered 110 million pounds (50,000 metric tons) of uranium in the Swanson/Coles Hill deposit, on land that it had leased near Chatham in Pittsylvania County. In response, the state of Virginia imposed a moratorium on uranium mining in the state. Marline dropped its remaining mineral leases and closed its local exploration office in 1990. The deposits occur as breccia-fill and veins in gneiss bordering the Triassic Danville Basin. Ore minerals are coffinite, uraninite, and uranium-bearing apatite.
In October 2007, Walter Coles, who owns the land over the Coles Hill deposit, announced that he and some other landowners had formed Virginia Uranium Inc. to mine the deposit themselves, if it can be done safely. In November 2007, the state issued an exploration permit to Virginia Uranium, to allow drilling test holes into the deposit. Drilling began in mid-December.
The state-imposed moratorium on uranium mining is still in effect. A bill proposed in the state General Assembly in January 2008 would have created a Virginia Uranium Mining Commission to determine if uranium mining could be done in a manner protective of human health and the environment, and to recommend regulatory controls. However, opponents of uranium mining succeeded in stopping the bill on March 3, 2008, when a committee to the House of Delegates delayed consideration of the bill until 2009.
In November 2008, the Virginia Commission on Coal and Energy voted unanimously to create a subcommittee to study the issue of uranium mining. In May 2009 the subcommittee approved a study of potential uranium mining and its safety and pollution issues. The study is expected to take about 18 months to complete.
In February 2010, Virginia Uranium contracted the National Research Council and Virginia Tech University to do a study of potential environmental and economic effects of uranium mining in Virginia. The study, funded by $1.4 million from Virginia Uranium, will produce a report by December 2011.
Uranium was discovered at the Midnite Mine deposit on the Spokane Indian Reservation, Stevens County, Washington in 1954. The deposit was mined from an open pit 1956-1962 and 1969-1982. Production through 1975 was 8 million pounds (3,600 metric tons) of U3O8. The uranium is contained in autunite, uraninite, and coffinite, with gangue minerals pyrite and marcasite. The ore occurs as disseminations, replacements, and stockworks in Precambrian metamorphic rocks of the Togo formation, in a roof pendant in Cretaceous porphyritic quartz monzonite.
Other Washington state uranium mines include the Sherwood mine, located a few miles south of the Midnite mine, and the Daybreak mine, located about four miles west-northwest of Mt. Spokane. The Daybreak mine is recognized as the source of the finest museum-quality specimens of autunite and meta-autunite yet found.
Wyoming once had many operating uranium mines, and has the largest known uranium ore reserves of any state in the U.S. The Wyoming uranium mining industry was hard-hit in the 1980s by the drop in the price of uranium. The uranium-mining boom town of Jeffrey City lost 95% of its population in three years. By 2006, the only active uranium mine in Wyoming was the Smith Ranch-Highland in-situ leaching operation in the Powder River Basin, owned by a subsidiary of Cameco. The mine produced 907 metric tons of yellowcake (uranium concentrate) in 2006, making it the leading uranium producer in the United States.
The radiation hazards of uranium mining and milling were not appreciated in the early years, resulting in workers exposed to high levels of radiation. Inhalation of radon gas caused sharp increases in lung cancers among underground uranium miners employed in the 1940s and 1950s.
In 1950, the US Public Health service began a comprehensive study of uranium miners, leading to the first publication of a statistical correlation between cancer and uranium mining, released in 1962. After much secrecy and suppression, the federal government finally regulated the standard amount of radon in mines, setting the level at 0.3 WL on January 1, 1969. After years of deflecting criticism and lobbying, Congress eventually passed 1990’s Radiation Exposure Compensation Act (RECA), granting reparations for those affected by the radiation, with amendments coming ten years later in 2000 to address criticisms and problems with the original act.
Uranium mining and milling has left a legacy of environmental problems. Out of 50 present and former uranium milling sites in 12 states, 24 have been abandoned, and are the responsibility of the US Department of Energy. Accidental releases from uranium mills include the Sequoyah Corporation Fuels Release in Oklahoma and the Church Rock Uranium Mill Spill in New Mexico.