Uranium mining in the United States 1954 in the Sierra Nevada of Kern County, along the Kern River about 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 US 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,
Depleted uranium Depleted uranium has been used in a number of sampling calorimeters (such as in the D0 and ZEUS detectors) due to its high density and natural radioactivity. Normal functioning of the kidney, brain, liver, heart, and numerous other systems can be affected by uranium exposure because, in addition to being weakly radioactive, uranium is a toxic metal, although less toxic than other heavy metals, such as arsenic and mercury. It is weakly radioactive but is 'persistently' so because of its long half-life. The Agency for Toxic Substances and Disease Registry states that: "to be exposed to radiation from uranium, you