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Longwall mining has a better safety record than continuous mining. The danger of roof falls has been <br />removed. The roof supports are set in a straight line on the face with skin to skin contact. The safest <br />place in the mine is directly underthe steel canopies of the self-advancing supports. <br />Longwall mining has two major disadvantages. The initial capital investment is extremely high and the <br />system is totally interdependent. In longwall mining there are no alternatives, no spare sections, no <br />spare equipment. If any one element shuts down the entire system is down. <br />BME has designed its mining plan to permit the highest resource recovery in the most cost effective <br />and safe manner. <br />Longwall panels are planned within the permit boundary wherever it is geologically possible. All other <br />areas will be mined by the more flexible room and pillar mining when economicallyfeasible. <br />There are three factors within the Deserado Mine permit area which prohibits the use of longwall <br />mining: <br />1) Areas where the seam height is much less than 7 feet <br />2) Areas where the overburden is less than 150 feet <br />3) Areas where the panel boundary geometry does not allow large blocks of coal for longwall <br />mining. <br />Areas in which the overburden over the extracted seam approaches zero are critical to longwall <br />systems. The country rock in these areas are usually weathered and fractured because of its proximity <br />to the outcrop. The roof rock can break up right up to the surface, placing the total weight on the <br />longwall roof supports and gate entries. There are no calculable values for the minimum overburden <br />over longwalls as this depends on a wide range of factors such as compaction and strength of the roof <br />rock, tectonic stresses and configuration of the surFace. <br />BME has selected 150 feet as the minimum overburden thickness to ensure a dependable, <br />control table longwal I system. <br />Rio Blanco County Special Use Permit#81-1 <br />ExhibitB-Mining Plan <br />September2000 <br />4 <br />