Helium is found in large amounts in minerals of uranium and thorium, including cleveite, pitchblende, carnotite and monazite, because they emit alpha particles ( helium nuclei, He 2 + ) to which electrons immediately combine as soon as the particle is stopped by the rock.
22.
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.
