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I ~ I • PROJECT DESCRIPTION The Colowyo Coal Company, L.P. (Colowyo) mine is a multiple seam surface mining operation. The East Pit has been in operation approximately 18 years. Initial excavations have begun for the West Pit which will be mined down through F-Seam coal. The Streeter Pit area will be mined down through the X-Seam. The relative locations and extent of these mine areas are shown on Fig. 1. Atypical section showing the north wall of the West Pit and coal seam locations and dip is shown on Fig. 2. There is no known underground mining near the West PR or Streeter Pit areas. Auger mining of the X-Seam is under consideration both in the West Pit and the Streeter Pit. As the West Pit initial box cut is deepened, the C or D-Seam and the E-Seam are planned for auger mining. Proposed auger diameters include 5, 6 and 7 foot circular diameter augers. Preliminary recommendations are provided for a • rectangular miner method with a 13 foot width and adjustable height. The anticipated depth/penetration of the circular augers is on the order of 300 to 500 feet. The initial box cut for the West Pit will extend through the F-Seam to depths on the order of 350 feet. The proposed location and configuration is shown on Fig. 1. Excavation through the Y-Seam has been completed to the extent shown as of September, 1995. The north wall of the West Pit will consist of a 250 foot high section from the X-Seam floor to the F-Seam floor. Above this slope the X and Y- Seam cuts will be stepped back as illustrated on Fig. 2. The excess spoil pile will be located to the north of the north wall slope. The toe of the slope will extend as close as possible to the slope based upon stability considerations. The east wall of the box cut will be approximately 350 feet high (Y-Floor to F- Floor) and the Y-Toe cut will be closer than for the north wall (Fig. 2). The excess spoil pile will not influence the east or west walls of the West Pit. COLOWYO GOAL COMPANY, L P. CTLrT 2],SBS 2