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�. General Plan and Scope <br /> This document combines all previous reports on the waste pile into one <br /> report. Detailed documentation is not included herein. Please refer to the original <br /> reports for complete documentation and other details. The previous reports are <br /> titled Waste Bank Design, Technical Revision 'I, April '199t and Waste BanK <br /> Design Technical Revision, September t99'I. - <br /> According to stipulation No. 07 issued by the Division of Minerals and <br /> Geology of the State of Colorado, the design of the permanent coal waste bank at <br /> p.o5.3C8� National King Coal Mine must satisfy the requirements stated in mine regulations <br /> � 3fq ) 4.f O and 4.'i'I. This document attempts to address <br /> Z'p5 �Uo>King Coal m nens�te a manner appropriate to the scale and scope of the National <br /> The coal refuse will be mine waste rock extracted over the life of the mine. <br /> The material is composed of dense, medium grained sandstone with occasional <br /> shale and carbonaceous shale partings. With the atldition of the proposed wash <br /> plant the production of waste rocK will increase with an estimated ultimate volume <br /> of one million cubic yards. <br /> The waste bank will be a valley £II type pile located in the east drainage. The <br /> existing coal waste banK, approximately 25,000 cubic yards, will be modiFed fo <br /> meet the design specifications stated in this report and will be incorporated into <br /> the permanent structure. <br /> A limit equilibrium static analysis was pertormed using effective stresses to <br /> assure long term stability of the bank. The face of the bank will have a surtace <br /> slope of 2.5:'1 or less. The east side drainage will diverted around the pile on the <br /> north side and will be tied into the clear water diversion system. An intercept <br /> channel will be constructed on the south side of the bank to collect contaminated - <br /> runoff from the pile and runoff from adjacent areas and route it to the <br /> sedimentation ponds. An underdrain system will be constructed beneath fill and <br /> will also drain into the ponds. <br /> The mine is located in a geologically stable area that rates low in seismic <br /> activity. Because the waste bank lies below the mining levels, there will be no <br /> subsidence effect. <br /> 2. Detailed Design <br /> Waste Material Properties <br /> As stated, the coal refuse is mine waste rock composed of dense, medium- <br /> grained sandstones. This material comes from the Menefee Formation, Mesa <br /> Verde Group, Upper Cretaceous age. The sandstone is a quartz sandstone with <br /> January 7998 <br />