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T Mountain Coal Company Exhibit 69 West Elk Mine Mine Dewatering & Treatment Facilities • through the sump. There are two 20-inch cased boreholes (completed per MR212) that will serve as alternate recircaltation boreholes and/or boreholes for water level indicators. These holes are located near the dewatering borehole. The treatment portion of the building will house several pieces of treatment equipment. The equipment will include two 1,000 gpm conventional high-rate flocculation and sedimentation units, chemical feed equipment, and chemical storage equipment. Presedimentation Basin A concrete-lined Presedimentation Basin will be constructed to provide mine water settling prior to treatment. The basin will consist of two cells for redundancy. Each cell will be 16 feet (interior dimension) wide, 78 feet (interior dimension) long, and 12 feet deep (water depth) and there will be a common wall between cells. Two baffle walls aze provided in each cell to eliminate flow short-circuiting and to promote even flow distribution. The effluent weir will provide even flow splitting to the subsequent treatment units. Sludge will be collected at one end of the basin and periodically washed to the Sludge Drying Lagoons. • Decant Return Basin and Pump Station Liquid decant will be generated at the Sludge Drying Lagoons (see description below) when supematant, or settled water at the water surface, is withdrawn. As such, a decant return basin will be provided to serve as a flow equalization basin and to return the water to the head of the plant (Presedimentation Basin) for further treatment. The Decant Return Basin will include two submersible pumps. The structure will be a package, buried concrete basin and pump station. Access will be restricted by a lockable access hatch. Sludge Drying Lagoons Sludge generated by the treatment facilities, which will consist primarily of fine grain silt and clay, will be discharged to the Sludge Drying Lagoons. The Sludge Drying Lagoons will reduce the water content of the sludge, therefore reducing the volume of sludge that must be disposed. The total solids percentage of the sludge dischazged to the lagoons will typically be 1 to 4 percent. The sludge will be allowed to settle in the lagoons and supernatant (settled water at the water surface) will be withdrawn. The supematant will be dischazged to the Decant Return Basin. Afrer a sufficient drying period is provided in the lagoons, the dried sludge will be Oct. 1997 TR83, Revised May 1998 MR213