2009-08-20_PERMIT FILE - C1980001A

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Mine. Small areas on West Ridge occurred where mining continued to the coal outcrop just beyond the ridge crest. Since these areas were just below the drainage divide, "day-lighting of the areas was performed with the dragline. This was accomplished by the dragline back-dragging the material toward the pit, forming slopes which also drain in the pit's direction. Immediately following the "day-lighting" procedure a berm was constructed along the crest of the ridge to keep runoff confined. The berm will remain in place after backfilling to the top of the ridge to ensure all future drainage is directed towards the pit area and the sedimentation ponds. Other small areas exist which are just below the drainage divide, where there is no runoff except for sheet flow from the immediate area. Alternate sediment control measures which may be employed on these areas include, but are not limited to, contour furrows, straw bale filters, silt fencing, gravel surfacing, and erosion control matting. The Trout Creek water pump station pad located northwest of the Moffat pond is a small area approximately 65 feet by 85 feet requiring small area exemption status. The pump station pad was used for filling • water-trucks with the water pumped from Trout Creek for dust control purposes. Sedimentation and erosion control for the area after the pad is no longer needed includes, regrading the area, topsoiling and seeding. Runoff from the area will pass through a grass filter as it leaves the vicinity. Appendix 4.6-P contains the SEDCAD+ computer model results demonstrating that the runoff from the pad meets applicable effluent quality criteria. 4.6.1.8 Shop and Related Facilities Sediment Control Plan Drainage control for the shop, coal stockpile and explosives magazine areas will be provided by a series of 5 ditches, three culverts, a drop • Renewal-3 4.6-34 October 21, 1996