PERMFILE125651 - Laserfiche WebLink

Home Browse Search

The open pit haulback mining method is utilized for • both Pit 1 and Pit 2 (Figure 1). Topsoil will be removed and stockpiled by trucks, the front end loader and the road grader. The coal seam is overlain by interbedded shales, sands and mud- stones. The up to fifty feet of overburden is weathered and can be moved without blasting; however, the remaining over- burden must be drilled and blasted for removal by trucks and shovel or backhoe. The pit will follow the outcrop in a series of 30 foot high benches from the bottom of the pit to the surface. The final highwall slope will be constructed at an average of 2V:1H. After the overburden has been loaded into the trucks it will be hauled to the open end of the pit for backfill. Almost all overburden will be transported on in-pit haul roads that will advance as the pit advances. when extending Pit 1 to the south, overburden is hauled to the north end of the pit for backfilling. The overburden from the box cut of Pit 2 (approximately 600,000 cy) will be hauled • back to Pit 1. About 411,000 cy of the overburden in the stockpile (1,412,000 cy when swelled by 158) will be hauled to the final cut of Pit 2 for backfilling and the remainder pushed into Pit 1. See Figure 2 for location of overburden stockpile, Pit 2 box cut (Phase VI) and final cut (Phase IX). At the present time, Wyoming Fuel does not anticipate creating any new overburden stockpiles. The existing stockpile shown on Figure 2 will not be moved until the final cut is finished. Coal is mined using either the front end loader or backhoe to load trucks. Trucks haul the coal from the pit to the crusher, where it is crushed to 2"x0". Crushed coal is then hauled by independent contractor to Walden (12 miles) for loading on Union Pacific rail cars at the existing loadout or delivered directly to the customer. r] -za-