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Mountain Coal Company Exhibit 69 <br />West Elk Mine Sylvester Gulch Facilities <br />Drainage around the shaft pad and along the roads to the degasification hole will be <br />controlled by surface ditches and culverts. The drainage plan utilizes the existing natural <br />drainage wherever possible, and all culvert outlets are located such that they discharge to <br />natural drainage paths or constructed ditches. All ditches and culverts associated with the <br />site have been sized for the 100-year 24-hour storm event. Ditch and culvert designs are <br />included in Exhibit 66 and locations of al] hydrologic structures are shown on Map 54B. <br />Figure 3-E in Exhibit 66 details the drainage basins in the Shaft #3 area, and includes the <br />degasification hole site. Runoff from the shaft pad will be directed to the south end of the <br />pad via drainage swales, and sediment will be controlled using silt fence and/or straw <br />bales at the outlet from the shaft pad and below the toe of the MSE wall. A small area <br />exemption demonstration for the shaft pad is included in Exhibit 66. <br />Substation <br />A new electrical substation will be built to provide power to the new facilities within <br />Sylvester Gulch and to the existing Sylvester Gulch fan. This substation will also provide <br />dual power feeds to underground mining operations via cable drops down the shafts and <br />via an electric borehole located approximately 1800 feet south of the shafts. The need for <br />a new power source for mining operations is driven by safety and voltage drop <br />considerations since the existing source of power extends approximately 4.5 miles <br />through the mine. <br />The location of the substation will be in a western tributary of Sylvester Gulch <br />approximately 1/2 mile northwest of the shafts. The selected site is centrally located with <br />respect to facilities that it will serve, minimizes the length and disturbance required for <br />the incoming high voltage transmission line, and is outside the projected subsidence <br />angle-of--draw. The substation equipment consisting of transformers, voltage regulators, <br />and switchgear will be mounted on individual two foot thick concrete slabs totaling <br />approximately 1728 sq. ft. in plan area, within a fenced area of approximately 140 feet by <br />240 feet. A truck turnaround area approximately 80' x 160' will be located west of the <br />substation. Approximately 74 individual steel columns to support overhead buswork and <br />equipment will be mounted on two foot diameter by ] 0 foot deep concrete caissons. Oil <br />containment for the transformers will be installed consisting of a total of 180 feet of two <br />foot wide by one foot deep concrete footer with a six inch wide by two foot high concrete <br />wall, and approximately 700 sq. ft. (total) of PVC liner material. Approximately 220 feet <br />of pre-cast lightweight concrete cable trench, two foot high by three foot wide, will also <br />be installed in the ground within the substation boundary, and a separate grounding grid <br />approximately 20 feet by 20 feet will be installed to the west of the substation. The entire <br />area within the fence, as well as the truck turnaround area, will be graveled approximately <br />one foot thick. <br />Topsoil Salvage and Hydrology <br />6 Nov. /99h PR07R; Revised Mu~~ 1997 MR21h <br />Rev(red Jul 1997 hIR219,~ Revised June 200J h1R297 <br />