<P> 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 . </P> <P> The McDermitt Caldera in Malheur County was the site of intense uranium exploration in the late 1970s . Portland - based Oregon Energy is currently planning development of the Aurora deposit, near McDermitt . </P> <P> 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 . </P> <P> 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 . </P>

Where does the us get most of its uranium