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A degasification borehole is located approximately 225 feet west of the electric borehole site in <br />Sylvester Gulch. It was constructed during the summer of 1997. The purpose of the degasification <br />hole is to vent mine gases to the outside atmosphere. A vacuum pump placed next to the hole <br />pumps gases out of the mine and through surface piping to move the gas up and away from the site. <br />A small metal building was constructed to house the degas pump, as well as an air compressor. An <br />as-built description is provided in Exhibit 68. <br />Sylvester ('.,,lch~ MCC has designed mine dewatering and treatment facilities to be located within <br />the Sylvester Gulch drainage. The treatment facility will provide a method of reducing total <br />suspended solids (TSS) from the mine water, if necessary, and the mine water will be dischazged to <br />the West Fork of Sylvester Gulch incompliance with NPDES discharge pemut requirements. <br />MCC drilled one 18-inch cased borehole, one 16-inch borehole (completed as a 12-inch cased <br />hole), and two 20-inch cased boreholes during the summer of 1997 to access the operational sump <br />in the northeast comer of the 1 ONE Tailgate. Following the completion of ventilation seals on the <br />LONE and 11NE longwall panels, this area will become the NE Panels Sealed sump. MCC will <br />utilize the sealed sump as a large volume mine water storage azea and will pump the water out of <br />the mine through the boreholes for treatment (if necessary) and dischazge to Sylvester Gulch. The <br />smaller borehole will serve as a recirculation loop to the sump and the two 20-inch cased boreholes <br />will serve as alternate recirculation boreholes and/or boreholes for water level indicators. Refer to <br />the Probable Hydrologic Consequences section of the permit for additional discussion of the sumps. <br />The treatment facilities will include a dewatering pump station and treatment building, <br />presedimentation basin, decant return basin and pump station, sludge drying lagoons, and finishing <br />pond. A detailed discussion of each facility is provided in Exhibit 69, Sylvester Gulch Facilities <br />Area. <br />An overhead 46KV high voltage transmission line from Colorado Highway 133 to the substation <br />located in Sylvester Gulch was constructed in the Spring of 1997. Distribufion power lines connect <br />the substation to the two ventilation shafts, the Sylvester Gulch F-Seam fan, the electric borehole, <br />mine dewatering pump station and the existing main mine facilities. The substation located within <br />the main mine facilities was abandoned in 1998, due to landslide movement, and is discussed in a <br />later section of this permit. A 15 KV overhead line extends from a substation to the supplemental <br />exhaust fan in Lone Pine Gulch. <br />This electrical system meets the requirements of the National Electrical Safety Code, the National <br />Electde Code (NEC), the National Fire Code, MSHA, and all applicable State or local codes. <br />Grounding and ground fault-protection systems have been built into the electrical distribution <br />system according to Federal mine safety regulations. Raptor protection systems have also been built <br />2.~5-22 Revised Jan /996 RN03; Revised Nm. 1996 PR07; RevisedJaa 1997 TR79; Revised Jul. 1997 TR82 <br />Revised Oct. 1998 TR86; Revised Jun. 1999 TR90 <br />