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Mountain Coal Company <br />West Elk Mine <br />RPE Shafts Project Plan <br />POWER SUPPLY <br />MCC is currently evaluating three options to bring in the source of electrical power <br />required for operation of the ventilation shaft. These include: <br />Routing of power through Sylvester Gulch, adding to the pole sets down the gulch <br />with a step down transformer and pad. This option would require the addition of <br />approximately six additional pole sets. <br />2. Direct muting from the pad sets at the North Soils Storage Area to the Sha$ Area <br />Would include an addition of a step~iown transformer, pad and 3 additional pole <br />sets. <br />3. idtilization of the Havc~rsnest Transformer Pad and installation of pole shafts <br />across Highway 133 to the Shah Area This option would require approximately <br />four additional pole sets. <br />Power supply muting options are presented in Map 54. <br />CLEAR WATER DIVERSION <br />Surface hydrology analyses were previously performed on the RPE watershed area <br />during the original RPE permitting. Details of this analysis and resulting diversion, <br />discharge and containment design are presented in TR-90, TR-79 and E~rhibit 70, Volume <br />l OB, and MR 303. <br />The pre-existing ditches and RPE pond will be utilized in controlling surface run-0ff <br />associated with the project area. There will be need for some supplementary cleaz water <br />diversion as placement of the ventilation shaft is uphill of the uppermost cleaz water <br />diversion ditches. DCW-8A will run against the south hillside conveying water towards <br />Sylvester Gulch. The water will run through a 24-inch comrgated metal pipe (CMP) <br />culvert into DCW-8B flowing into Sylvester Gulch The drainage channels will be lined <br />in riprap with a D50 of 9-inches. DCW-8A and 8B will both be trapezoidal riprap <br />channels with a side slope ratio of 1.5:1,0. The diversion ditches and culvert were <br />designed to accommodate the peak distribution of the 100-yeaz 24-hour storm event, type <br />II distribution, with an adequate freeboard of 1.0-feet. <br />Positive drainage will be maintained on the pad area during construction and ail drainage <br />control features will be installed prior to the construction of the ventilation shaft. Surface <br />run off from the drilling pads will be collected in the existing perimeter sediment ditches <br />(RPE-1) and conveyed to the RPE sediment pond. <br />Drainage from the undisturbed upgradient area toward the south will be diverted <br />westward towazd Sylvester Gulch, and eastward towards the unnamed shallow gulch that <br />TR-105 Page 7 of 12 <br />