2010-07-21_PERMIT FILE - C1982056A (7)

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will be placed in the bottom 15 feet of the shaft and the remainder of the shaft will be filled with inert material including the shaft cuttings and collar excavation materials. A cement plug will be poured from 10 feet below grade to • within approximately 3 feet of the surface. The remaining 3 feet will be filled with soil, and graded to blend with the surrounding terrain. As noted in the discussion of construction for the 18 -Left Ventilation Shafts, any required pressure —grout boreholes will be sealed at the time of construction. Cement grout will be pumped through the boreholes to seal any wet zones encountered and the boreholes will be filled with grout and allowed to set -up on completion of grouting operations. Any surface casing extending above ground surface would be cut -off flush with or below natural ground level. The MAC borehole will be plugged and sealed using the same methods as previously described for the shaft seal. Following removal of structures and equipment, and plugging and sealing of the shaft and borehole(s); any cuttings remaining in the temporary mine waste disposal pit will be covered with excavated shaft collar material; road culverts will be removed and disposed of off -site; road -base and surfacing materials will be removed and placed on the shaft pad; and the shaft pad, substation area, sedimentation pond, and light -use road disturbance areas will be regraded to reestablish effective drainage and blend with the surrounding terrain. Cover over any cuttings remaining in the cuttings pit will be a minimum of 2 feet of suitable material, and the postmining configuration will approximate the premining contours. As -built certification will be provided to the CDMG following final closure, backfilling, and grading of the cuttings pit. Any excess road -base and surfacing materials not required to reestablish approximate original contour will be hauled off -site and disposed of. Stockpiled topsoil will then be replaced on those disturbed areas where it was previously removed and seeded with a pastureland seed mixture. Fish Creek Ventilation Shaft and Dewatering and Water Treatment Installation (MR07 216) The Fish Creek Ventilation installation had a useful life of approximately seven years, until the first set of longwall panels were mined -out. The fan building, duct -work, and fan have been removed from the site. The borehole was temporarily sealed, as described in the response to Rule 2.05.4(2)(g), and was used only for discharge from the • excess flow diversion line from the Fish Creek water treatment system. In 2007, the shaft installation was modified for use as a dewatering well to replace the inoperable Fish Creek South Dewatering Borehole. Upon completion of mining, and when the system is no longer required, all facilities will be removed and the site reclaimed. Removal of the surface facilities will involve removal of the modular electro- coagulation units (2); dismantling of surface structures, which includes the powerline, transformer and pad, any remaining chemical and pump control equipment, buildings and pads; fencing,; stubbing -off and capping buried piping; and demoilition of building foundations. The concrete demolition debris will either be hauled to the refuse site for disposal or hauled to a landfill. Final reclamation of the dewatering wells and ventilation shaft will involve excavating down 4 feet from grade around the casing, cutting off the steel casing 3 feet below grade, hanging steel decking from the top of the cut -off casing (this decking will be 30 feet below the top of the cut -off casing), placement of 30 feet of concrete in the casing (for a 3 -foot diameter cased hole, the 30 foot x 3 foot diameter cement plug would weigh approximately 32,000 pounds, which would be more than adequate to resist the calculated hydrostatic pressure and provide an effective seal). The remaining 3 feet will be filled with soil, and graded to blend with the surrounding terrain. . The access road will be graded to blend with the surrounding terrain, and the culvert will be removed. The entire area will be topsoiled and seeded with the appropriate seed mixture. After the facilities are removed, the site will be regraded to blend with the existing terrain and the stockpiled topsoil redistributed over the area. The soil material stored adjacent to the site will be redistributed over the dewatering site and reclaimed road segments will be seeded with the pastureland seed mixture. Approved permanent access roads will remain intact for use by the surface owner. During the 10 -year liability period, TCC will maintain the road for monitoring purposes. After bond release, the land owner will assume responsibility for the road. The northern short • section (2,500 feet) of the access road will be reclaimed unless otherwise approved by the CDRMS. The soil windrowed or stockpiled adjacent to the road will be seeded with the rangeland seed mixture. RN08 -05 2.05-106.1 03/12/10