<P> While uranium is used primarily for nuclear power, uranium mining had its roots in the production of radium - bearing ore from 1898 from the mining of uranium - vanadium sandstone deposits in western Colorado . The 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 . In 1960 annual U.S. production peaked at 17,055 metric tons U O. Until the early 1980s, there were active uranium mines in Arizona, Colorado, New Mexico, Oregon, South Dakota, Texas, Utah, Washington and Wyoming . </P> <P> 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 . </P> <P> The average spot price of uranium oxide (U O) increased from $7.92 per pound in 2001 to $39.48 per pound ($87.04 / kg) in 2006 . In 2011 the United States mined 9% of the uranium consumed by its nuclear power plants . The remainder was imported, principally from Russia and Kazakhstan (38%), 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 $50 per pound U O, reserves are estimated to be 539 million pounds; however, at a price of $100 per pound, reserves are an estimated 1227 million pounds . 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 . </P> <P> The radiation hazards of uranium mining and milling were not appreciated in the early years, resulting in workers being 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 . In 1969, the federal government regulated the standard amount of radon in mines . In 1990, Congress passed the Radiation Exposure Compensation Act (RECA), granting reparations for those affected by mining . 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 . </P>

Where does the united states get most of its uranium