OCR

Fewer flights would minimize the number of operating personnel. The four flight system resolved the problem of later increasing the capacity in an advantageous manner. The ultimate capacity of 2000 LTPH required three 300-hp drives for each flight. The initial capacity of 1000 LTPH would be obtained using two of the three drives. In other words, capacity of the initial installation was actually more than specified; that is, two-thirds of 2000 LTPH or 1260 LTPH instead of 1000 LTPH; this at a price which was competitive. The additional capacity made available in the initial phase would further defer the day that still greater capacity was required. Also, the ultimate city would be available by adding only one-third of the total horsepower instead of half. Features of Installation Described The conveyer system and some of its unique features are described in the following paragraphs: Truck Unloading Bins: The 4 in. by 0 ore with moisture of approximately one percent is hauled from the mine by bottom-dump trucks which have pay- load capacities of 54 and 75 LT each. At the present time there are eight rent types of ore being conveyed. To make the conveyor system inde- pendent of the short but frequent delays of a trucking operation, particularly when handling a wide variety of ore types, required that there be two separate and fairly large truck unloading bins. These surge bins are 30 ft diameter, approximately 80 ft deep, and have a capacity of 2000 LT each. are in rock and were constructed using shaft sinking techniques. They are concrete lined and the concrete is protected by a lining of abrasion resistant steel plate. Each bin is equipped with two remotely controlled vibrating feeders, with provision to add a third feeder when the capacity of the conveyors is expanded. Tunnel Conveyor: This conveyor is 48 in. wide and has a belt speed of 460 ipm. The belting is five ply, nylon reinforced with a top and bottom breaker strip. The drive components are a 40-hp motor direct-connected through a parallel shaft double reduction herring-bone reducer with a solenoid operated thrustor brake mounted oil an extension of the input shaft of the speed reducer. The conveyor has a gravity take-up located at the tail pulley. This conveyor moves ore from the truck unloading bins to the first flight of the main convey- Downhill Conveyors: The components of all four conveyors are identical and interchangeable. The conveyors are 36 in. wide and have a belt speed of 600 fpm.