Engineering and Mining Journal - Whether the market is copper, gold, nickel, iron ore, lead/zinc, PGM, diamonds or other commodities, E&MJ takes the lead in projecting trends, following development and reporting on the most efficient operating pr
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SKIP-WAY TRAM APRIL 2016 • E&MJ; 33 www.e-mj.com The ropes are anchored in the ground near the bottom station and span the entire slope of the mine up to the skip unloading station at the top without any intermediate supports. At the pit rim, the ropes are led over a mast and anchored either in the ground or in a counterslope. The run of the ropes from the bottom sta- tion to the top station is determined by the position of the unloading station, the deadweight of the ropes, the rope tension and resultant sag, and additionally by the upward or downward running skips. Rope tension is set so that both laden and emp- ty skips maintain a safe distance from the mine slope and any roads leading into or out of the mine. The two parallel rope anchor stations at the rear of the skip unloading stations serve as tensioning and storage systems for additional rope should the bottom sta- tion be relocated as mining progresses. The use of two parallel track ropes in each direction allows the use of standard - ized, full locked ropes. Two track ropes result in a shorter skip carriage as the number of running wheels needed to dis- tribute loads is divided over two ropes. Polyamide running wheels, proven in ca- ble cranes, are used to reduce wheel-rope contact pressure and maximize rope life. The Skip Way System offers sever- al options for skip unloading at the top station. As shown in Figure 4, ore or minerals can be transported on one rope system so that automated skip discharge takes place in this part of the conveying system above a crusher. Once the locking mechanism opens, the entire skip load of uncrushed ore or mineral slides into the crusher bin. After crushing and possibly screening the raw material is transported out of the mine area via a conventional belt system for further processing. The second rope track of the Skip Way System can be used, for example, to transport waste material, which is load- ed from the skip back onto mine trucks at the top station. The trucks can then transport their load to the waste dump on virtually fat roads. As most mines already have nearby screening and crushing sta- tions, both skip unloading stations at the top of the mine could also be used for truck loading and onward transportation. The skips are connected by a common travel rope and transport material out of the mine within preselected travel cycles. As one skip is being loaded by a dump truck at the bottom station, the second skip is located at the top station above the crusher or the truck loading point. Figure 5 illustrates the run of the travel rope of the upward traveling skip and the run of the rope over a defector sheave in Figure 3—Skip with spring-mounted support frame, rope defector sheave and tandem rope carriage. Figure 4—Overview of skip unloading stations with crusher charging and truck reloading. Figure 5—Diagram of rope run with coupled skips over a drive station.