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Wes( E!k Mine <br />De~asifieation Site <br />A degasification borehole is located approximately 225 feet west of the electric borehole site in <br />Sylvester Gulch. It was constmcted 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 />Mine Dewatering and Treatment Facilities Description <br />Svlvester Gulch: 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 discharged to <br />the West Fork of Sylvester Gulch in compliance with NPDES dischazge permit 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 />IONS and 11NE longwall panels, this azea will become the NE Panels Sealed sump. MCC will <br />utilize the sealed sump as a large volume mine water storage area and will pump the water out of <br />the mine through the boreholes for treatment (if necessary) and discharge 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 [he permit for additional discussion of the sumps. <br />The treatment facilities will include a dewatering pump station and treatment building, <br />presedimen[ationbasin, 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 />Given MCC's experience to date (October 1998) with the good quality mine water discharges from <br />the NW Panels Sealed sump through the Lone Pine Gulch Pipeline, MCC has indefinitely <br />postponed the construction of the treatment components of the above described facilities. MCC has <br />constructed only the pumping components in a building and the finishing pond. However, <br />dependent on the actual quality of water pumped from the NE Panels Sealed sump, MCC may build <br />the treatment facilities in the future. <br />Lone Pine: MCC has proposed, but indefinitely postponed the construction of a pond that would be <br />utilized exclusively to contain and treat (if necessary) water that is pumped from the NW Panels <br />Sealed sump. Mine water is pumped from the Lone Pine Gulch ventilation portal and transported <br />through a 12-inch HDPE pipeline. As the water has been of sufficient quality to meet discharge <br />limitations, it has been directly discharged to Lone Pine Gulch, and subsequently to the North Fork <br />of the Gunnison River. The pond will only be constructed in the future if the mine water quality <br />r1 <br />LJ <br />2.05-22 Revised A'ov. 1996 PRO%: Revised Feb /997 b1R709:Revised,~lay l99i ,NR?I6, Rev~srd Jul. /997TR81; <br />Revised Oct. ! 998 TR86 <br />