Patience Lake

Overview

Patience Lake potash mine is located near the city of Saskatoon in the Canadian province of Saskatchewan.

At Patience Lake potash is mined in situ by using a solution mining method where hot water is pumped through drillholes into the underground potash deposit and the resulting brine is then recovered through another set of drillholes and directed to the evaporation pond.

The potash produced at Patience Lake is being used in fertilizer and agricultural products.

Final product is shipped by rail to North American users and through ports to international customers.

Location

The Patience Lake potash mine is located 6 km southeast of Saskatoon in Saskatchewan (SK), Canada on Highway 16 and 9 km (5 miles) east on Highway 394 (at Bentley Road, RM of Blucher, SK).

Saskatchewan 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.

Saskatoon – ‘at the place of many Saskatoon berries’ in local language - is a 234,000 people city located in the central part of the province on the South Saskatchewan River.

Saskatchewan has about 53 percent of global potash reserves.

Geology & 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.

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).

Potash deposits in Saskatchewan are about 1,000 m to 3,000 m below surface and are flat lying and pretty much undisturbed. The ore is made of approximately 55 percent sodium chloride (rock salt), 40 percent potassium chloride (KCl, or potash) and 5 percent clay and other insoluble materials. It also contains small quantities of iron oxide which colors the ore in red or pink.

Saskatchewan hosts 50% of the world's reserves.

Mining & Operation

Originally a conventional underground operation, Patience Lake was converted to a solution mining operation in 1988 after two periods of closure due to flooding. 

Potash is dissolved from the ore by circulating brine through the flooded conventional mine workings 1,000 meters (3,280 feet) below the surface, which extend up to 10 kilometers (6 miles) from the mine shafts. Hot water is pumped through drill holes in the underground cavity and as it circulates through the potash beds it takes potash and other salts into solution.

As a result of capacity expansion and debottlenecking the ramped up operational capability has reached 0.6 MMT per year.

Saskatchewan produces 30% of the world's supply of potash.

Processing

The brine is pumped to a surface evaporation pond by nine submersible pumps each pumping about 6,800 liters (1,800 gallons) per minute. At the surface pond potash brine is cooled by the prairie winter until the potash precipitates. Then the potash is crystallized and dried. Potash crystals are milled to produce granular and lawn & garden products for agricultural applications. Warehouses with a combined capacity of 155,000 tonnes are used to store the product.

The cool stripped brine (free of potash or any other dissolved salts) is then heated and reinjected into the mine to start dissolving potash again. The remaining potash in the ponds is removed via floating dredges and pumped back to the mill.

The potash produced at Patience Lake is being used in fertilizer and agricultural products.

In 2011, the mining operation produced 390,000tonnes of muriate of potash (KCl).

Product from Patience Lake travels by Canadian Pacific Railway to centers throughout North America for domestic sales or to ports for delivery offshore.

Environment & Community

The company contributes funds to local organizations and programs and spends a few million dollars per year in environmental initiatives and programs.

New collective bargaining agreements were signed in 2011 and extended to 2014.