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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IN-PIT CRUSHING JULY 2017 • E&MJ; 55 www.e-mj.com "The benefit of putting a Mobile Siz- ing Station in ore is that it can crush at the face and, instead of hauling rock to a gyratory, they use the Surge Loader to fill the trucks, which haul the ore to a feed- er that supplies the mill or a secondary crusher instead of a primary," Pitchford said. "Everyone is interested in in-pit crushing, but they are not interested in conveying if they have already made the investment in large haul truck fleet." This form of continuous mining would allow an operation to mine from benches in the exact same manner as they would with trucks while crushing ore at the face. "We have done a lot more work as far as being able to relocate this system quickly," Pitchford said. "We are looking at some 'Star Wars' like ideas as far as spotting the trucks. We are trying to set this up where the shovel operator sees the screen and, after the shovel is moved into position and the operator sees all the other equipment is lined up properly, he can start loading and keep loading until the surge loader is waiting for trucks. As long as trucks are passing through, they can keep feeding." If the shovel operator makes sure the Mobile Sizing Station is fully charged, it will allow him enough time to reposition the shovel and restart mining operations again, Pitchford explained. The Mobile Sizer Station combines a D9 apron plate feeder with a 1500 series MMD sizer, a transfer belt and loughing (or slewing) conveyor. Both belts are rubber, and they can slew that conveyor into any position for the surge loader up to 60°. From the bridge above the Mobile Sizer Station, the operator can monitor every- thing that's happening between the shov- el the Mobile Sizer Station and the Surge Loader. If the system stalls for whatever reason, the operator can reverse and re- start it. "The sizer station operator, howev- er, can't see the situation with the truck," Pitchford said. "So, the plan for now is to place a system on the shovel. If the shovel operator sees no truck and that the Mobile Sizer Station's hopper is full in front to him, he can stop loading. The Surge Loader will have stopped because there are no trucks in position and the Mobile Sizer Station will not run if the Surge Feeder is not running. The Surge Feeder loads continuously as the trucks queue. They never reverse into position. The processing capacity of the The Surge Loader loads a haul truck in 75 seconds (98% fill factor). The Surge Feeder loads continuously as the trucks queue. They never reverse into position. The processing capacity of the Mobile Sizer Station is greater than the cycle time of the shovel so the shovel operator is unable to overwhelm the system.