Rocanville

Overview

The Rocanville mine site is located 18 km east of the community of Rocanville in south-east Saskatchewan, Canada.

In 1970, Rocanville was the last Saskatchewan mine to come into production. It is 100% owned by the PotashCorp, a former Crown corporation which went public in 1989, when it had its initial public offerings on the Toronto and New York stock exchanges.

Potash is a general term covering several types of potassium salts, of which the most important is potassium chloride, the mineral sylvite. Potash is a nutrient essential for plant growth, and is a cornerstone of modern agricultural fertilizers. Roughly 95 per cent of world potash production goes into fertilizer, while the other five per cent is used in commercial and industrial products - everything from soap to television tubes.

Saskatchewan represents approximately one-third of the world's potash production capacity and has approximately 53% of global potash reserves.

Rocanville is a conventional long room and pillar underground potash mine, operating at a depth of 960 meters. Mining operations employ continuous mining (boring) machines.

It produces granular and standard product for agricultural use and standard industrial product. Annual capacity is 3.0 million tonnes KCl.

Location

Saskatchewan - the 'swift flowing river' in Cree language - is a landlocked Canadian prairie province and has a population of 1 million people mostly living in the southern part of the province, a region characterized by a semi-arid steppe climate - hot summers and windy cold winters.

The province of Saskatchewan is an important Canadian granary. Beef cattle production and forestry are other important economy sectors. As for the mining sector Saskatchewan is a world leader in uranium and potash production.

The Rocanville potash mine is located in the south-east part of the province some 18 km east of the community of Rocanville. The mine site can be reached by a mine access road from Highway 8.

The railroad reached Rocanville in 1903, the town was incorporated in 1904 and it was named for the first postmaster Rocan de Bastien. The population grew to 450 by 1920.

Only about five per cent of the potash produced in Saskatchewan is consumed in Canada.

About two-thirds of the exports go to the U.S., where Saskatchewan potash fills approximately 70 per cent of the market demand. The province is also a major supplier to the large Pacific Rim offshore markets: China, Japan, Malaysia, Korea and Indonesia.

Geology and Mineralization

The sylvite (potash) deposits of Saskatchewan formed over 350 million years ago as a result of the final stage of evaporative concentration of sea water in a middle Devonian sea.

This sea extended from the southern Northwest Territories southeastward through Alberta, southern Saskatchewan, and into Manitoba and North Dakota. Saskatchewan has the majority of the resulting potash deposits as this stage of evaporation was largely confined to the province.

The productive Praire Evaporite Formation comprises a series of flat-lying sedimentary deposits of interbedded sylvite (KCl), carnallite, halite beds and clay and dolomite beds.

Stratigraphy of the region is dominated by three important potash bearing beds: the upper Patience Lake member (exploited by mines employing underground and solution mining methods); the middle Belle Plaine member (solution mining); and the lower Esterhazy member (underground and solution mining).

At Rocanville the mine exploits the 960 m deep Esterhazy potash formation. The flat lying potash bed averages a thickness of about 2.5 m and grades just over 21 percent K2O.
 

Mining & Operation

Rocanville is one of the lowest-cost potash production facilities in the world and has a capacity of 3.0 million tonnes KCl per year.

Its mine workings are 960 meters (3,150 ft) below the Saskatchewan prairie and stretch as far as 11 km (7 miles) north and 7 km (4.3 miles) south from the mine shafts. The shafts carry employees down to the mining level and ore up to the mill.

The Rocanville mine is a conventional potash mine and uses long room and pillar mining techniques to extract the ore.

The mine employs five four-rotor Marietta continuous mining machines. Each machine cuts a profile of 2.4 m by 8.23 m (8 ft by 27 ft) and advances at a rate of up to 30 cm per minute.

Each machine typically produces 700 t per hour. Once mined, the ore passes directly from the miner onto a conveyor system which transports the ore to underground storage bins for hoisting to the surface. 

A central control system which supervises all of the mining and processing operations had been implemented and resulted in visible operational and metallurgical improvements.

Processing

The ore is crushed to liberate the sylvite from halite and scrubbed and de-slimed to remove the clay. After conditioning with reagents, it enters the flotation process in which the KCl is floated off the top of the cells. It is then de-brined, dried and screened.

The potash is then graded for application as fertilizer and industrial product, and stored in a 210,000-tonne bin.

Rocanville produces standard and granular grade potash for agriculture and industrial use. The agricultural potash consists of the Granular (SGN 285) and Standard (SGN 100) products.

Most of the Rocanville potash is shipped by railways to centers throughout North America for domestic sales or to ports for delivery offshore. 

Potash destined for offshore markets is exported by Canpotex, the export company owned by all Saskatchewan potash producers, from the West Coast, the Great Lakes and the Gulf of Mexico.

More than half of potash sales go offshore. In China, where farmers grow two or three crops a year, rice is the largest consumer. In Brazil, most is used on soybean, sugar cane and corn. In Malaysia, oil palm is the largest consumer of potash. In the US, corn is the major consumer of the agricultural grades of potash.

Environment & Community

In 2010, alone the mine contributed more than $150,000 to regional community projects and organizations. It has also spent $33.3 million on local purchasing.

The company also reduced water consumption by engineering the elimination of a crystallization circuit, maximized brine injection to solve the problem of high brine pond levels caused by record precipitation, and spent $25.3 million on environmental programs and initiatives.