Denver Basin
Relatively small amounts of uranium ore have been mined from the Dakota Sandstone along the western edge of the Denver Basin. The Mann mine, near Morrison, Colorado, produced 16,000 pounds (7.1 metric tons) of uranium oxide from 1955 to 1961. The Mike Doyle mine in El Paso County produced 280 pounds (130 kg) of uranium oxide from Dakota sandstone in 1955. Also in 1955, a Dakota sandstone mine in Larimer County produced 8 pounds of uranium along with some vanadium.
The Leyden coal mine, north of Golden, Colorado, produced 4500 pounds (2.1 metric tons) of uranium oxide from 1954 to 1956, as a byproduct of coal mining in the Laramie Formation.
Rancher Solomon Schlagel discovered uranium in Weld County, Colorado in 1969 when he noticed that cuttings from seismic shotholes were anomalously radioactive. Exploration in the 1970s defined a number of roll-front uranium deposits in the Upper Cretaceous Laramie Formation and Fox Hills Formation in Weld County. They all occur along the southern margin of the Cheyenne sub-basin of the Denver Basin.
Wyoming Minerals Corporation operated a pilot in-situ leaching plant from June 1977 to May 1978, successfully extracting uranium from a deposit in the Laramie Formation near the town of Grover. The aquifer was then remediated.
Power Resources Corporation began in-situ mining the uranium deposit in the Fox Hills Formation at Keota, Colorado in 1980. The Keota deposit was estimated to contain 5 to 10 million pounds (2300 to 4500 metric tons) of uranium oxide, but the project was halted because of low uranium prices.
Read more about this topic: Uranium Mining In Colorado