Bentonite is a soft clay substance composed essentially of clay minerals of the smectite (montmorillonite) group. Its color ranges from white to light olive green, cream, yellow, earthy red, brown and sometimes sky blue when fresh but yellowing rapidly with exposure to air. When wet, bentonite is highly plastic and slippery. Bentonite feels and appears greasy or waxy. There are two basic types of bentonite depending on whether they contain sodium or calcium in the crystal lattice. The sodium type swells when wet whereas the calcium type does not.

The region between Avonlea Creek and Moose Jaw Creek south of Wilcox contains large reserves of swelling bentonite in the marine Bearpaw Formation. Other occurrences include the St. Victor area and Twelve Mile Lake near Pickthall. Calcium or non-swelling bentonites have been encountered near Pelly, Moosomin, Rockglen and Eastend.

Saskatchewan's only bentonite quarry is operated by Canadian Clay Products Inc. near Truax. The processing plant, located at Wilcox, has an annual production capacity of about 80,000 tonnes per year. The bentonite produced in Saskatchewan is a clay of high swelling capacity when mixed with water. The bentonite is produced by quarrying and processed by drying, adding soda ash, grinding and bagging. Reserves are estimated to be eight to 10 million tonnes.

Saskatchewan product is sold mainly in Canada from Quebec westward, but the main market is in Western Canada. Wyoming and Greece are major competitors. Much of the Saskatchewan production is used as fertilizer carrier, animal feed binding, reservoir sealing and as a foundry sand binder. Future opportunities for swelling bentonite include its use as a pesticide carrier, as an agent in water and effluent purification, and in the production of pet litter.

Open the Mineral Resource Map of Saskatchewan.

Link to the Geological Atlas of Saskatchewan.