Uranium mining in Colorado the Slick Rock, Gypsum Valley, Uravan, and Gateway mining districts. Uranium mining in southwest Colorado goes back to 1898, when a miner dug ten tons of yellow ore that tested high in uranium and vanadium out of a deposit at Roc Creek in Montrose County, Colorado, and shipped it to France, where M. M. C. Friedel and E. Cumenge identified the new mineral that they named carnotite. The mineral was mined for its vanadium, with uranium as a byproduct. Although radium had been discovered in 1898, it had been derived from pitchblende, and the radium content of carnotite was not
Uranium ore Mineralization may be primary, that is magmatic-related or as secondary mineralization due to leaching, remobilization and re-precipitation. The principal uranium mineral in volcanic deposits is pitchblende, which is usually associated with molybdenite and minor amounts of lead, tin and tungsten mineralization. Volcanic hosted uranium deposits occur in host rocks spanning the Precambrian to the Cenozoic but because of the shallow levels at which they form, preservation favors younger age deposits. Some of the more important deposits or districts are Streltsovskoye, Russia; Dornod, Mongolia; and McDermitt, Nevada. The average deposit size is rather small with grades of 0.02% to 0.2% UO.