Industrial Minerals in Northeastern Wyoming

Abstract Northeastern Wyoming (Campbell, Crook and Weston Counties) contains many industrial mineral deposits of past and present production and future potential. This area is the largest bentonite producing area in the world. In addition to bentonite, crushed limestone, clinker (baked and fused rock), and sand and gravel deposits are being worked for construction aggregate. Fluorite, clay, gypsum, dolomite, and halite have been produced in the past from this area. Gypsum, fluorite, aggregate raw materials and ornamental and dimension stone have promise for future development. Zeolites associated with bentonite may be a possible by-product of bentonite production and should be investigated by the bentonite producers. Industrial mineral production should continue to provide jobs and cash flow to the region. Bentonite is used primarily in domestic oil well drilling fluid. It is also used for iron ore smelting, soaps, and cosmetics. Due to the decline in oil well drilling, bentonite production has been decreasing. Limestone, sand and gravel, and clay occurrences may be developed to serve a regional market area of southeastern Montana, northeastern Wyoming, and western North Dakota, South Dakota, and Nebraska. The large gypsum resource represents an opportunity for development for sale to regional cement plants or for possible wallboard plant construction in the area.