Abstract

The Bighorn Basin of northern Wyoming contains significant industrial mineral resources. Two plants produce wallboard from gypsum mined nearby. Six plants refine bentonite mined from several locations on the eastern flank of the basin. Limestone, mined in nearby Montana, is processed into lime at a plant near Frannie. Other industrial minerals currently being produced in the Bighorn Basin include construction aggregate (river rock and crushed rock) decorative stone, and recovered sulfur.

Industrial minerals produced from the Bighorn Basin in the past include silica sand for glass manufacture, refractory and construction clay, chemical grade limestone, decorative stone, and mined sulfur.

Uranium was mined in the past from the Little Mountain District northeast of Lovell. Smaller amounts of uranium and thorium have been produced from prospects elsewhere in the basin.

Industrial minerals in the Bighorn Basin which have economic potential include silica sand, increased production of decorative stone, mined sulfur, chemical grade limestone, magnetic sand, and zeolites. The production of gypsum and bentonite should continue to be an important contribution to the economy of the region.

Although the domestic uranium market is currently depressed, increasing prices may make it an important commodity for the future. Uranium is found in Precambrian rocks beneath the Cambrian unconformity, a geologic relationship similar to the large uranium deposits of the Athabasca Basin of Canada and those of Northern Australia. A large thorium resource is present in paleoplacer deposits of the Cambrian Flathead Sandstone in the Bald Mountain area.