The Xstrata-Copper Kidd Metallurgical Plant site, called the Met Site, near Timmins, Ontario, refines about 1% to 2% of the world’s copper and zinc production plus other related products. The operation consists of a concentrator, a copper refinery, a copper smelter and a zinc plant. It produces about 131,000 tons of copper, 140,000 tons of zinc and about 540,000 tons of sulfuric acid annually.
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In 1990, the plant installed four ITT/AC, SRL, C-HD, Size 8x10-21 rubber-lined slimes thickener tailings pumps in the concentrators tailings pump house to pump thickened slimes tailings from the thickener through the tailings distribution lines. The pumps were originally supplied with packed stuffing box assemblies.
The Stage #1 pump receives tailings slimes from the tailings thickener at a static-head pressure of 30 psig to 50 psig, depending on the level of the tank from which this pump draws. It discharges at 60 psig to 80 psig into the Stage #2 pump, which discharges to the tailings pond at 100 psig to 190 psig.
For 18 years, the plant endured recurring pump failures that led to significant maintenance, downtime and clean-up costs. It was almost impossible to control stuffing box gland water spray, which leads to pump barrel oil contamination and oil lip seal deterioration. In the end, premature barrel failures combined with gland water control deficiencies, gland follower stud failures and rapid sleeve wear made this a poor pump application.
In addition, the pressure of the gland water injected to lubricate the braided packing and prevent the abrasive solids from entering the stuffing box often would drop too low and destroy the braided packing. Then, the slimes tailings spilled out of these stuffing boxes and onto the floor. If left undetected, the operators could find a two-foot to three-foot depth of slimes tailings on the pump house floor.
“During these upset conditions, other motors and instrumentation were frequently contaminated if they happened to be in the way of the flood,” explains Hans Bekeschus, senior technical sales representative, Northern Ontario, for Flowserve’s Flow Solutions Division. “The tailings pump house is approximately two miles away from the concentrator plant, and an operator would only travel to the tailings pump house once every eight-hour shift by truck to inspect,” adds Bekeschus. The plant repacked the pumps every two to three weeks and replaced the pump shaft sleeves about every three months.