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<br />The mining system selected for the Deserado Mine is primarily the longwall mining method. Some part <br />of the deposit may be worked in part by the room and pillar, with pillar extraction mining method. <br />III.A.2.a Room and Pillar Mining Room and pillar mining or continuous mining has long been the <br />backbone of the United States' underground coal mining industry. The advantages of the continuous <br />mining system are due to its adaptability and flexibility. This system easily adapts to changes in the <br />geological and physical conditions of the mine. Using this system, it is possible to exclude in part any <br />poor sections of the deposit and it is possible to Negotiate geologically disturbed areas of the mine and <br />easily adapt to variations in the seam. The continuous mining system has great flexibility. The <br />equipment can be easily moved around to different locations in the mine and the overall system is only <br />minimally affected by a stoppage of any one unit. <br />The production from each continuous miner section is relatively small and this mining system is <br />generally more hazardous and more expensive to operate than a longwall system. The overall coal <br />reserve recovery from room and pillar mining seldom exceeds 55 percent because all of the pillars <br />cannot always be safely extracted. <br />• III.A.2.b Longwall Mining. Longwall mining has gained great acceptance in the United States. It has <br />gained great acceptance because of its three apparent advantages: <br />1) High recovery <br />2) High production <br />3) High safety <br />In longwall mining, coal is extracted from panels that are several thousands of feet long and several <br />hundreds of feet wide. The shearer which is a powerful cutting machine with a huge drum on each end <br />rips a strip of coal from the longwall face. The coal falls onto a face conveyor consisting of flexible <br />steel pans which transfers the coal away from the longwall. As the shearer passes, the roof supports <br />are advanced immediately and the roof behind them is allowed to cave. When the shearer returns on <br />the cleanup pass, the face conveyor is pushed forward and the cycle is ready to be repeated. <br />Permit Renewal #3 (Rev, 8/99) III-4 <br />