Jeffrey Skipway- J. M. Fletcher
J. M. Fletcher Plant Engineer, Jeffrey Mine, Canadian Johns-Manville Co., Ltd., Asbestos, Quebec
This paper covers the major operating and maintenance problems encountered since start-up of a 30,000-t.p.d. ore skip way, and the steps taken to overcome them. The skipway system handles uncrushed ore, with individual blocks ranging up to 2 tons in size. This material falls 14-25 feet from truck box to skipway bins, and 12 feet from birs to skip. The impact, wear and vibration experienced from this operation were well beyond anything originally anticipated. Within the first few weeks of operation, many major modifications were required; the drive over structure was reinforced with an additional 10 tons of steel stiffeners, bin liners were replaced by 6-in jaw crusher plates, and skips were reinforced to bring their tare weight to 62,000 lbs. In addition, operating doors, chutes, gates and mechanisms had to be strengthened.
After satisfactory operation was obtained, many further improvements were gradually introduced to reduce production delays, operation and maintenance costs, and safety hazards. Some 8,000,000 tons of ore have now been handled through the system at a skipway cost of 2.4 cents per ton, and at a truck haulage to skipway cost of 8.2 cents per ton. From an average pit depth of 400 feet, an over-all truck-skipway cost of 10.6 cents and a 16-minute cycle has been achieved, as compared with a total truck
haulage cost of 15.5 cents per ton and a 29-minute cycle. Thus, despite some rather critical problems during start up, the over-all benefits of this skipway application now appear well within original estimates.
aluminum, manganese steel, mild steel, ore, tare weight, Control, Controls, Operation, Ore, Ores, Skips, steel, Steels