Allan

Overview

PotashCorp owns and operates a potash mine at Allan, Saskatchewan. Production of potash from the underground mine began in 1968. 

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.

Location

The Allan mine site is located approximately 40 km (24 miles) east of Saskatoon on Highway 16 and 7 km (5 miles) south on Highway 397 near the town of Allan, Saskatchewan, Canada.

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.

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).

Virtually all Allan underground mining rooms are in the potash mineralized zone situated approx 15m below the top of the host evaporite salt, the Prairie Evaporite Formation.

Depth to the top of the main mineralized zone varies between 1020 m and 1100m, averaging approx 1040m over most of the mining and exploration area.

Mine workings are protected from aquifers in overlying formations by overlying salt and potash beds which overlie the mineralized zone.

Mining & Operation

The Allan mine is a conventional underground mining operation whereby continuous mining machines are used to excavate the potash ore by the stress-relief mining method, with continuous conveyor belt transport of ore from the mining face to the bottom of the production shaft. 

Allan mines potash at a depth of 1,040 meters, producing granular, standard and industrial grade for agricultural and industrial use. Its annual capacity is 1.9 million tonnes KCl. Production began in 1968.

The underground workings stretch some 10 kilometers north, 5 kilometers west and 5 kilometers east from the shafts.

The mine uses stress-relief mining techniques developed specifically for the site. This provides a stable and safe work environment while allowing the efficient extraction of ore. The mine uses six two-rotor continuous mining machines. Each machine can cut a 3.3 meter by 5.5 meter profile (11 feet by 18 feet wide) and can produce 500 metric tonnes per hour. Once mined, the ore passes directly from the mining machine onto a mobile conveyor system which transfers the ore to the main conveyor system, where it is transported to underground storage bins and then hoisted to the surface for processing.

Current expansion work, which began in 2008, is expected to be complete by late 2012. The ramp-up to full 2.7 million tonne capability is set to be reached by 2014 - an increase of 900,000 tonnes. The estimated $550 million project involves modifying the mine's production headframe to accommodate larger hoists, skips and conveyors.

Processing

In the mill the ore is crushed to free the KCl, then scrubbed to remove the clay. After conditioning with reagents, the ore enters the flotation process where the KCl is skimmed off the top of the flotation cells. The KCl is then de-brined, dried, screened and graded with the finished products transferred to surface warehouses for storage prior to loading in rail cars.

The mine produces: Granular SGN 285; Standard SGN 90; WSM 0.2 Chicklets; WSM 0.2 SGN 25.

Most of the Allan's potash is shipped by rail via Canadian Pacific and Canadian National railways to centers throughout North America for domestic sales or to ports for delivery offshore.

An expansion to the mining operations is to be completed by 2014. The mill expansion includes the installment of new process control equipment and the construction of a new substation and power supply system.

Environment & Community

In 2010 alone the company reduced water use by approximately 200 liters per minute by making changes to the mill. It re-designed the new dryer burners as to reduce greenhouse gas emissions.

The company also maintained flex bales in ponds to promote nesting of migratory birds.

Potash Corp regularly invests in local communities and provides support for different educational initiaves.