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Sctriaz - 2.05.3 <br />supplemented by installation of field located and engineered rock downdrains and a <br />• toe ditch that will intercept and route runoff to Sedimentation Pond D. <br />D. Mme Portals and Declines -The Elk Creek Mme reserve area will be accessed by <br />declines driven from portak located neaz the D Seam subcrop in Ells Creek Canyon. <br />Portal installation and initial decline construction will involve cut/fill excavation and <br />installation of two sets (manway and conveyer/temporary ventilation entries) of <br />steel circular or aroh support sections on a grade to reach competent ground. Select <br />backfill rnatenak will be placed and compacted around and over the portal structures <br />to assure the stability of these structures during operations. Development will <br />continue, with soft-ground excavation of the two 10 x 20 foot main decline entries <br />to the north to intercept the D Coal Seam Portal entries will be driven on <br />approximately 100-foot centers. A third entry will be added approximately 250 feet <br />north of the point where soft-ground development u initiated. Material excavated <br />from the declines is classified as mine development waste and will be utilized as fill <br />material for the Elk Creek portal bench and road if compatible with design <br />compaction specifications. Any unsuitable or saturated materials will be hauled to <br />and placed in the West Valley Fill in a manner that facilitates effective drainage and <br />coruohdation. <br />E. Ventilation Shafts and Fan Installation(s) -Where the main entries intercept the D <br />Coal Seam, the entrees will be tamed to the west and expanded to a full five-entry <br />configuration. Two ventilation shafts will be sunk from the surface to intercept the <br />main entries. Material excavated from the ventilation shafts will be utilized as fill <br />material for the Elk Creek portal bench and access road if compatible with design <br />• compattion specifications. A ventilation fan(s) will be installed on one or both <br />shaft(s) to increase ventilation airflow and pressures. Atypical fan installation will <br />consist of a ventilation fan, steel fan housing and ductwork, drive motor, and fan <br />controls mounted on a concrete slab foundation. Power will be provided to the fan <br />drive motor from the mine electrical distribution system <br />F. Substation No. 4 and Powerline -Anew substation will be established to provide <br />power for both the mine power system and ancillary support equipment including <br />mine fans, pumps, and conveyor drives. The substauon, to be located in the upper <br />portion of the Ells Creek Mme portal bench area, will consist of a concrete slab <br />foundation, grounding field, control building, support stnrcttues, transformers, <br />control and switching equipment, and achain-link security fence with locking access <br />gate. A power distribution line tying to the main Delta-Montrose Electric <br />transmission line will run up the west side of Ells Creek Canyon to supply power to <br />the new substation. <br />G. Mme Dewatering Wells and Underground Sump - A series of mine dewatering wells <br />will be drilled from the surface prior to initiation of mine development work to allow <br />dewatering of the D Coal Seam ahead of development and to provide for future <br />discharge from a mine water collection sump. It a currently anticipated that four <br />wells will be required ranging in depth from 15 to 200 feet in depth. The wells will <br />be located along a line extending from south of the portal area to the northeast <br />comer of the Ellt Creek portal bench, neaz the stratigraphic low point of the futttre <br />D Seam Mme Dewatering Sump: The wells will be complered as (r to 8-inch cased <br />boreholes with perforated casing in and immediately above and below the D Seam <br />. with high-capacity submersible pumps. Initially, the pumps will draw directly from <br />the D Seam and discharge directly to Elk Creek, since water recovered directly from <br />the D Coal Seam should meet applicable effluent standards without further <br />treatment. <br />PR04 2.05-22 Revised August 2000 <br />