CANADA'S MODEL SALT MINE

In the town of Goderich, today, Mr. Platt's activities are carried on by the Sifto Canada, Inc., in two separate modern plants. One is a rock salt mine located in Goderich Harbor and the other an evaporating plant located on the escarpment of the Maitland River.

Developed in 1959, the Sifto Salt mine shaft, surface mill and loading facilities are attractively situated on the site shown above. Offering access to transportation by road, rail and water, the plant site was built-up, largely from fill, in Goderich harbor. Sifto's first mine shaft is circular, measures 4.88 m (16 feet) across and is completely concrete lined; it extends from the surface down to the bottom of the salt beds a distance of 549 m (1,800 feet); a second shaft, also 4.88 m (16 feet) in diameter, is located 61 m (200 feet) away. The first shaft is used for hoisting salt to the surface, the second shaft is for ventilation, personnel and equipment.

In 1981 construction started on an expansion program to increase capacity from 2,000,000 t (2,250,000 tons) to 3,150,000 t (3,500,000 tons) annually. The objective could not have been achieved without sinking a third shaft and increasing significantly the quantity of ventilating air introduced into the mine. Like No. 2, this shaft is also circular and concrete-lined but is 6.7 m (22 feet) in diameter. The reason for the increase in size is to make the cross-sectional area approximately equal to the combined total of the other two shafts, thus keeping the velocity of the ventilating air flow within tolerable limits.

In the mining operation a 12.7 cm (5 inch) gap, (or undercut) about 3.7 m (12 feet) deep is cut across the width of the mining face; the whole face, from floor to roof and side to side is then drilled with holes. The holes are filled with explosive and blasted. The undercut allows the blasted salt to fall to the floor where it can be loaded by giant loading machines. Approximately 1,620 t (1,800 tons) of salt fall from each blast.

As safety precautions the roof must be "scaled", to remove any loose salt or rock that didn't fall in the blast, and bolted to ensure that no future cracks or falls occur. These operations are carried out by men working from a "giraffe" (opposite page), that can reach to the 13.7 m (45 feet) high roof. The fallen rock salt is loaded by machine into giant diesel trucks and conveyed by them to an underground processing mill. Here the salt is crushed and screened into its various sizes and stored underground until required for shipping when it is hoisted to the surface.

In the underground maintenance shop mobile equipment is repaired, including overhaul of diesel engines, torque converters, and other power-train components. Electric power is carried down the shaft to the shop, mill, and electric powered production machines.

There is another processing mill on the surface where the salt can be screened again, if desired, and where it is packaged into the various sizes and grades in which it is shipped. There are also bulk storage bins and silos on the surface that store sufficient salt to allow prompt service in loading large boats, trucks, or railroad cars. This is a most modern salt mine, highly automated, producing nearly 50% of the rock salt produced in Canada.