Uraninite named, was either unknown, impossible or not economically feasible). The mineral has been known at least since the 15th century from silver mines in the Ore Mountains, on the German/Czech border. The type locality is the historic mining and spa town known as Joachimsthal, the modern day Jáchymov, on the Czech side of the mountains, where F. E. Brückmann described the mineral in 1772. Pitchblende from the Johanngeorgenstadt deposit in Germany was used by M. Klaproth in 1789 to discover the element uranium. All uraninite minerals contain a small amount of radium as a radioactive decay product of uranium. Marie
Uranium mining in Colorado back uranium-mining projects. There are no currently producing uranium mines in Colorado. Hydrothermal uranium deposits are present through a widely spaced area in the Front Range of the Rocky Mountains, in Larimer, Boulder, Gilpin, Clear Creek, and Jefferson counties. The first uranium identified in the USA was pitchblende from the Wood gold mine at Central City, Colorado in 1871. Pitchblende orebodies were also discovered in the Calhoun mine, the Kirk mine, and some others. About 122,000 pounds (55 metric tons) of uranium oxide (UO) were shipped at irregular intervals from six gold mines in the Central City district from 1872