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found in Exhibit 56. The permeability contrast <br />found in the pile will cause most of the leachate <br />water to perch within the refuse pile and above the <br />native soils. A shallow water mound will build <br />within the pile and cause the water to migrate <br />laterally to small seepage area at the edge site. <br />During 1991, there were no visible flows from the <br />pile toe and midsection underdrain. <br />Upper Refuse Disposal Area - The upper waste rock <br />pile was approved for construction June 14, 1986. <br />This pile has not been constructed and construction <br />is not proposed for this permit term. The final <br />pile will cover approximately 40 acres and contain <br />five million tons of coal reject and developmental <br />waste rock. The primary predicted impact to ground <br />water is the development of leachate from <br />precipitation infiltration through the pile. The <br />approved plan calls for the installation of five <br />lateral subdrains to collect this leachate. The <br />drains will help prevent the formation of a large <br />perched leachate aquifer that may effect the <br />stability of the pile. Additionally, the drains <br />will intercept most of the leachate and prevent it <br />from entering the shallow colluvial aquifers. The <br />subdrains will daylight into surface channels where <br />the leachate will flow to a sediment pond. As this <br />pile is constructed, spoil wells will be installed. <br />ii. Mitigation of Ground Water Impacts - <br />The applicant anticipates no degradation of ground <br />water quality during mining. The applicant will <br />treat any mine water effluent as necessary to meet <br />water quality standards prior to discharge and <br />there will be no uncontrolled mine water discharge <br />after mining is complete which might otherwise <br />degrade surface streams or ground water. The <br />operation plan indicates most water used for dust <br />control will be absorbed on the coal and carried <br />from the mine, thereby minimizing the quantity to <br />be treated. Any discharge will be delivered and <br />treated in the sedimentation ponds and discharged <br />as specified in the NPDES permit. <br />To monitor the changes in water quantity and <br />quality, the West Elk Mine has an extensive ongoing <br />Hydrologic Monitoring Plan. Twenty-three wells are <br />currently being monitored in the alluvium, the <br />Rollins Sandstone, the Barren member, the F seam, <br />the B seam and E seam. Sampling occurs seasonally <br />(three times a year). Parameters monitored <br />include, water level, pH, conductivity, <br />-41- <br />