2001-12-11_PERMIT FILE - C1981019 (2)

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COLOWYO COAL COMPANY EXHIBIT 7 • DESIGN OF SURFACE RUNOFF CONTROL STRUCTURES IN 1~RODUCTION This exhibit includes the calculations, sketches, and narrative description far the constructed and proposed works for handling the surface runoff of the Colowyo Coal Company's mine between Meeker and Craig, Colorado. The designs for these Features have been made in accordance with Colorado State requirements as published in "Regulations of Colorado Mined Land Reclamation Board for Coal Mining," by the Mined Land Reclamation Division, Colorado Department of Natural Resources, Denver, Colorado, 1980. The components of the surface drainage works consist of diversion ditches, drainage of mine fill areas, road ditches, road culverts, and sedimentation ponds. DITCHES Various ditches have been constructed and ore proposed for diverting, collecting • and channelling surface drainage. These ditches have been broken into two groups, with the first group consisting of the ditches in and around the mining area, and the second group consisting of ditches in the working area, along the haul road, and in and around the loading ores. Mining Area Ditches These ditches consist of two diversion ditches to divert flow from undisturbed area away from the mining area, one ditch to collect water coming off disturbed area and to direct the water to a sedimentation pond, and three ditches within the mined area' for collecting and directing wafer to sedimentation ponds. Details of these six ditches are given in Table 1 and the cross sections are portrayed on Figures 1 thru 3. The first of these ditches, listed as Diversion No. 1 to Prospect Gulch, was built in 178 to exclude drainage from undisturbed ores at the head of Streeter Gulch from entering the mining area. This ditch will remain in service through 1982, after which it will be removed by mining through the location of the ditch. •