1988-04-11_PERMIT FILE - C1981008A (17)

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wells, etc. completed in aquifers will be sealed using cement or other suitable sealant. The sealant will be placed in the hole from the bottom to within ten feet of the surface. Surface plugs used to complete the permanent sealing of holes, wells, etc. will be selected and used only if the CMLRD gives prior approval . All associated surface sites will be reclaimed following the cessation of mining. Peabody will submit to the CMLRD a proof of compliance report containing pertinent information on permanent sealing of any hole, well, etc. within 60 days of completion of such activities. Ground Water Quantity. The backfilling and grading of spoil materials is accomplished by dozers and scrapers (see Tab 20, Backfilling and Grading). Procedures outlined in Tab 20 will insure the eventual resaturation of the disturbed areas (pits) by creating greater porosities and hydraulic conductivities due to increased void volumes. In addition to backfilling methods, topsoiling and reclamation plans outlined in Tabs 21 (Minesoil Reconstruction) and 22 (Revegetation Plan) will enhance the potential for establishing reclaimed areas that exhibit similar infiltration rates and recharge capacities to premining conditions. Reseeding and mulching of redistributed topsoil will augment moisture retention and infiltration rates of the reclaimed areas. Mechanical manipulation of the regraded spoil and topsoil (chisel plowing, disking and ripping) will further aid the percolation of soil moisture downward toward the water tabte. Ground water inflow to the pits will be removed by pumping the water into sediment ponds. Design criteria for each sediment pond (both existing and proposed) is presented in Tab 13 (Facilities). Each pond is designed to contain runoff from a 10-year, 24-hour storm event plus additional storage capacity for water pumped from mine pits. Surface Water Quality. Design criteria for each sediment pond is outlined in Tab 13, Facilities. Each of the sediment ponds is designed to prevent additional contribution of sediment to stream flow outside the permit area and incorporates detention times sufficient to ensure that all applicable effluent standards will be met. All ponds are currently planned to be removed and reclaimed following the completion of mining. Peabody will apply for and obtain a modification to the existing NPDES Permit (CO-0000213) to incorporate the proposed 007 sediment pond in the Nucla East mining area. All terms and agreements specified in the permit will be adhered to during the mining operation. No treatment of pond effluent is anticipated. If it should prove necessary, Peabody will design treatment facilities or procedures to treat the equivalent of the 10-year, 24-hour effluent volume. 18-2 Revised 04/11/88