Abstract

Uranium ore deposits in the Paradox Basin have been mined for nearly nine decades; first for radium, then for the associated vanadium, and beginning in 1947 mainly for uranium. The principal host rocks are the Jurassic Morrison Formation and the Triassic Chinle Formation. The ore procurement program of the U.S. Atomic Energy Commission (AEC), for nuclear weapons, was responsible for the first “boom” of the 1950s and early 1960s. Public excitement was fueled by the discovery, in 1952, of a large unoxidized ore deposit on the flank of the Lisbon Valley anticline by a single individual. During this period, eight processing mills were constructed to provide uranium concentrate (yellowcake) to the government. A second, short lived, “boom” of the late 1970s and early 1980s was for nuclear power plant fuel. Two new mills were constructed in addition to two still in operation from the earlier boom.

Since 1947, mines in the Paradox Basin area have produced approximately 188.5 million pounds (85,500 Mg) of uranium oxide (U₃O₈) in ore. This represents approximately 21 percent of the domestic ore production. Tabular ore deposits in the Salt Wash Member of the Morrison Formation and in the Moss Back Member of the Chinle Formation have been the most productive. The vanadium content of the ore deposits in the Salt Wash has been an important co-product.

Due to declining prices, brought on by foreign competition and by excess inventories worldwide, the last mines closed in late 1990. There are numerous unmined ore deposits in the Paradox Basin, and the possibility to discover additional deposits is good. Higher prices and a strong market would no doubt renew interest in these deposits.