KIDD CREEK #3

The objective, said vice-president and general manager Michael Amsden, is to start “hoisting” ore via electric truck by 1991 and up the shaft by 1992. By 1996, an annual total of 726,000 tonnes of ore should be coming up from the No. 3 mine. The ore will be moved by rail haulage on the 4,700-ft level to the No. 2 shaft and hoisted from there to surface. Despite the new development, total annual ore output from the Kidd Creek mine will continue to fall.

A ramp has already been driven from the 4,400-ft (1,320-m) level to the No. 3 shaft location, and diamond drill holes have been drilled down the axis of the shaft to gather rock mechanics information. The contract for the 18-ft-diameter (5.5 m), concrete- lined shaft will probably be let this fall. Work will begin in the second quarter of 1990 and be completed in the fourth quarter of 1991. Development crews are working three shifts per day, five days a week, driving a drift from the No. 2 shaft on the 4,700-ft (1,410-m) level to the new shaft location, said Thomas Dowe, superintendent of the No. 3 mine.

Included in the $100-million development project will be two ramps. One to the 5,200-ft (1,560-m) level for the company’s 50-ton electric truck and one to the 6,000-ft (1,800-m) level for servicing what will be the deepest levels in the mine. Both ramps had been started at the time of our August visit. The shorter haulage ramp, which will be driven at a grade of 12%, should be completed in mid-1990. The longer (but smaller) service ramp, which will be driven at a steeper grade of 17%, is scheduled to be completed by the third quarter of 1991.

“If we ever go to the 8,000-ft (2,400-m) level, we’ll have the capacity to hoist 2,400 tons (2,181 tonnes) per day with this installation,” Amsden said.

The hoist planned for the No. 3 shaft is a 10-ft-diameter, 2,000-HP friction hoist equipped with one 12-tonne skip, a cage combination and a counterbalance.

Diamond drilling from the 4,600-ft (1,380-m) level in the No. 2 mine has indicated that the Kidd Creek orebody extends to a depth of 8,000 ft (2,400 m). But to reduce diamond drilling costs, more drilling to depth will be done from diamond drill stations on the new 6,400-ft (1,920-m) level, once it is established. “There seems to be a possibility that zinc and silver grades may increase at depth,” Amsden said. The company has published proven and probable reserves to the 5,600-ft (1,680-m) level. But reserves between the 5,600-ft and 6,000-ft (1,800-m) level have yet to be published.

A team of engineers is evaluating various mining methods under high- stress conditions. “Sub-level open- stoping is probably the method we’ll choose to mine the deposit at these depths,” said Eric Belford, director of mining.

Geothermal gradients are not as high in the mine as they are in the copper/nickel mines in Sudbury, Ont. Rock temperatures on the 8,000-ft level of the McIntyre gold mine in Timmins, for example, are reported to be about 64 degrees F (18 degrees C) compared with –108 degrees F (– 42 degrees C) in the Creighton mine in Sudbury.

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