Potash

The word "potash" is derived from the Dutch word Potasch, and originally referred to wood ash. Potassium carbonate, a basic chemical of pre-modern times, was extracted from it. Today potash refers to potassium compounds and potassium-bearing materials, the most common being potassium chloride (KCl). Potassium is the seventh most abundant element in the earth's crust, and is the third major plant and crop nutrient after nitrogen and phosphate. About 95% of world potash consumption is used in FERTILIZERS, with small amounts used in manufacturing soaps, glass, ceramics, chemical dyes, drugs, synthetic rubber, de-icing agents, water softeners and explosives. Other main potash fertilizer products include potassium sulphate (K₂SO₄) and potassium nitrate (KNO₃). The term "potash" comes from the pioneer practice of extracting potassium fertilizer (K₂CO₃) by leaching wood ashes and evaporating the solution in large iron pots.

Industry Growth
As early as 1767, potash from wood ashes was exported from Canada, and exports of potash and pearl ash (potash and lime) reached 43 958 barrels in 1865. There were 519 asheries in operation in 1871. The industry declined in the late 19th century when large-scale production of potash from mineral salts was established in Germany. In 1943, potash was discovered in Saskatchewan in the process of drilling for oil. Active exploration began in 1951. In 1958, the Potash Company of America became the first potash producer in Canada with the commissioning of an underground potash mine at Patience Lake; however, due to water seepage in its shaft, production stopped late in 1959 and, following extensive grouting and repairs, resumed in 1965. The underground mine was flooded in 1987 and was reactivated for commercial production as a solution mine in 1989.

In 1964, Kalium Chemicals Ltd opened the world's first potash solution mine near Regina, at a depth of 1585 m. Between 1960 and 1985, potash mine development was carried out mostly in Saskatchewan and New Brunswick. An important series of expansions during the 1970s and 1980s and successive incremental developments in the 1990s brought Canada to the forefront of potash-producing nations. Canada is the world's largest potash exporter, accounting for 43% of world trade. Canada exports potash to 40 countries. Our major markets are the US, China and Brazil.

Canadian Reserves
The Canadian potash industry consists of 9 underground mines and 2 solution mines operated by 3 companies employing more than 3400 workers. There are 8 underground mines and 2 solution mining operations in Saskatchewan, and one underground mine in New Brunswick. The most recently established Canadian mines were 2 near Sussex, New Brunswick, 50 km from Saint John, which began production in 1983 and 1985. However, in 1997, the Potacan Mining Company suffered massive inflows into its underground mine, which ultimately shut down permanently in the fall of that year.

Western Canada's potash deposits occur in the Middle Devonian Prairie Evaporite formation at depths in excess of 900 m. The deposits extend from central to south-central Saskatchewan, a few kilometres into Manitoba, and 200-300 km into northern North Dakota. Potash reserves are among the most extensive and the richest in the world. Canada's potash resource base was estimated at around 75 billion t of potassium chloride. In Saskatchewan, potash resource accessible by conventional underground techniques to a depth of 1100 m is estimated at 23 billion t KCl; an additional 50 billion t KCl are estimated to be accessible by solution mining. Potash ore grades range between 21% and 27% K₂O. In Manitoba, proven reserves in the southwest have been estimated to be a minimum of 40 million t at depths between 800 m and 900 m, with ore grades ranging between 23% and 25% K₂O.

Significant reserves occur in formations of the Windsor group in New Brunswick, where a potash resource base of more than 1.6 billion t KCl has been estimated. Proven reserves amount to 160 million t KCl at depths ranging between 600 m and 925 m. In New Brunswick, ore grades are generally richer than those of Saskatchewan, varying between 24% and 28% K₂O.

Production Capacity
Potash production capacity in Canada is estimated at more than 22 million t KCl. Saskatchewan's potash capacity is estimated at about 20 million t KCl, New Brunswick's potash milling capacity at 2 million t KCl. Potash producers in Canada produce fertilizer and industrial grades with K₂O content ranging between 60% and 65%. The bulk of potash production is spread among the standard (25%), coarse (30%) and granular grades (30%). Potash and common salt are often produced together; 6 potash operations also extract or recover co-product salt.

Potash is moved by truck (5%) and rail (95%). In Canada, potash is the third largest major MINERAL product in volume on Canadian railways and international shiploading.

Author M. PRUD'HOMME

Links to Other Sites
Life of a Rock Star
This site tells the story of an extraordinary group of scientists who tramped, paddled and rolled across Canada in the nineteenth century to study the geology of Canada's varied terrain.

A History of Mining and Mineral Exploration in Canada
Click on the cover image to view an online copy of a comprehensive report that traces the emergence of Canada's mineral industry. From Natural Resources Canada.

PotashCorp
The website for PotashCorp, the world’s largest fertilizer company by capacity, producing the three primary crop nutrients – potash (K), phosphate (P) and nitrogen (N). As the world’s leading potash producer, this company is responsible for about 20 percent of global capacity.