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
Enriched uranium of reactors". Naturally-occurring uranium is made of a mixture of U-235 and U-238. The U-235 is fissile meaning it is easily split with neutrons while the remainder is U-238, but in nature, more than 99% of the extracted ore is U-238. Most nuclear reactors require enriched uranium, which is uranium with higher concentrations of U-235 ranging between 3.5% and 4.5%. There are two commercial enrichment processes: gaseous diffusion and gas centrifugation. Both enrichment processes involve the use of uranium hexafluoride and produce enriched uranium oxide. "Reprocessed uranium" (RepU) is a product of nuclear fuel cycles involving nuclear reprocessing of spent