History Bentonite was recognized as a potentially valuable industrial clay back in the 1920's. Exploration and evaluation of bentonite by industry commenced during the seventies in the Truax area. The result was the establishment by Avonlea Mineral Industries Limited of a bentonite quarry near Truax and a processing plant at Wilcox in 1978. Description of Mineral Bentonite is a soft clay substance that belongs to the clay minerals group. This group is complex and consist of several mineral commodities, each having somewhat different mineralogy, geological occurrences, technology and uses. They are all natural, earthy, fine-grained minerals of secondary origin and composed of an alumina silicate structure with additional iron, alkalis and alkaline earth elements. Clay minerals are classified into two broad groups: specialty groups - in which bentonite is included, and kaolinitic clays, which include ball clay, fire clay (refractory clay), stoneware clay and kaolinite. These minerals rarely occur in a pure state, occurring with quartz, calcite, dolomite, feldspar, gypsum and iron oxide. Bentonite is a soft clay substance composed essentially of clay minerals of the montmorillonite group and is formed from chemical weathering of volcanic materials such as tuff or glass, volcanic ash , other igneous rocks, or from rocks of sedimentary origin. The nature of the weathering environment and the original composition of the volcanic material will generally determine the type of bentonite that forms. 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 it 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. swelling bentonites - sodium bentonite contains sodium in the platy molecular structure; has strong swelling properties (ability to swell to many times its dry volume when wet) and possesses a high dry-bonding strength non-swelling bentonites - calcium bentonite contains calcium in its structure; has a far lower capacity to swell when wet and usually exhibits greater adsorptive characteristics. Location 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 (of the Ravenscrag Formation). Calcium or non-swelling bentonites have been encountered near Pelly, Moosomin, Rockglen and Eastend. Mining The bentonite produced in Saskatchewan is a clay of high swelling capacity when mixed with water. To be economically mineable, bentonite must be close to the surface. Material overlying the bentonite must first be removed by bulldozer, dragline or bucket excavator. The surface of the bentonite bed must be carefully scraped to remove impurities. Depending on the thickness and grade variation, the bentonite may be scraped off layer by layer or excavated with bucket loaders. The bentonite is processed by drying (sun-dried and kiln-dried), adding soda ash (to improve the swelling properties), grinding and bagging. It may be also be stored for bulk loading onto hopper trucks or rail cars. Producers of Bentonite Saskatchewan's only bentonite quarry is operated by Canadian Clay Products Inc. near Truax. The processing plant, located at Wilcox, has an annual productive capacity of about 80,000 tonnes per year. Uses of Bentonite Swelling bentonite has many uses, due to its high plasticity and gelling property, its ability to take on large quantities of water and its capacity to swell to many times its dry volume. The applications for swelling bentonite include: well-drilling mud, where several pounds of bentonite are added per cubic foot of water to form a gel which lubricates the drill bit, helps to keep the walls of the borehole intact, reduces loss of drilling fluid and, when circulated during drilling, helps to bring the cuttings to the surface. pelletizing and binding agent for iron ore prior to smelting binder and digestive aid in animal feed sealing agent for reservoirs, lagoons and other engineering projects plasticizer in ceramic clay bodies binder of foundry sand carrier of insecticide and pesticide agent in water and effluent purification absorbent material for cat litter The use as a binder in foundry molds is still considered a major application for which the swelling variety is preferred, although non-swelling bentonite is used for some foundry purposes. Some non-swelling bentonites, depending on their chemistry and molecular structure, can be altered by acid leaching to render them useful as catalysts for petroleum cracking or for bleaching animal litter such as cat litter. Economic Impact for Saskatchewan The demand for bentonite varies depending on the level of exploratory drilling for oil and gas. Saskatchewan product is sold mainly in Canada from Quebec westward but the main market is in Western Canada. Wyoming and Greece are major competitors. The Future: How Much is Left? Reserves are estimated to be eight to ten million tonnes.