2008-01-11_PERMIT FILE - C1982056A (2)

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grave] was placed on pad areas adjacent to the foundation slab. The foundation slab includes two reinforced concrete piers extending approximately one-foot above the slab surface to support and isolate the pump and drive assemblies. A 20 x 17 foot insulated pre-fabricated steel building was erected adjacent to the existing Electric Shop to accommodate the two VFD pump skids and drives, a heating and ventilation system, and provide for maintenance access. Three new powerpoles and a short connector line connect the pump installation to the existing Substation No. 7. Piping from the new pumping installation connects to the three existing underground water lines (suction, pressure, and recirculation) that run adjacent to the existing Electrical Shop. Design drawings and construction specifications for the Pumphouse foundation and building are provided in Exhibit 49F, and the Pumphouse location is shown on Map 24 (Sheet 1 of 3), Surface Facilities and Freshwater Systems. As part of the mine surface facilities, the Pumphouse addition will be reclaimed in conjunction with final reclamation of the mine facilities area, as described under the sub-heading "Swface Facilities" on page 2.05-101 of the PAP. In general, this will involve removal of the two pump and drive assemblies along with associated Swface piping (existing buried piping to be stubbed-off and abandoned in place); demolition and disposal of the Pumphouse building, foundations, and powerline and poles. The pad azea will be regraded to reestablish effective drainage and blend with the surrounding terrain. Stockpiled topsoil will then be replaced and seeded with a pastweland seed mixtwe. Washplant II Waterline and Connection fI'R07-59, Washplant III In order to supply adequate water to Washplant II, a new 10,000-foot, 6-inch HDPE waterline will be installed between Washplant II and the Area 1 Pit. A 5-6 foot deep trench will be excavated from the Area 1 Pit to the Washplant II location, adjacent to or in the same location as the existing 4-inch waterline. Since the trench will fall entirely within a previously distwbed azea, no topsoil remains and no soil salvage will be required. Once the waterline is laid in the trench and properly bedded, the trench will be backfilled and the material compacted. An additional pump will be placed in the Area 1 Pit and connected to the new waterline. Either a float or submersible pump will be utilized, with pump control and access from the existing pump-station access in the Area 1 Pit. In addition, a short buried 8-inch FIDPE connector line will be extended from the Washplant II water supply line to the existing 8-inch waterline that now runs between Pond A and the existing Washplant I, to provide analternate/supplemental water supply for Washplant II. A manhole with manual valves or automated control valves will be used to control flow to the Washplant. Rockdust Distribution A rckdust tank located north of the portal area, as shown on Map 24, Surface Facilities and Freshwater Systems, supplies rckdust to the underground mine (see Figure 16, Rockdust Bin Operations Design). The tank pad and associated truck access/unloading area is surfaced with pit-run gravel to control drainage and erosion. A borehole measuring 12.25 inches in diameter drilled to the underground workings supplies rckdust, and power for the Tank Feeder Drive and Top Blower. The pipes inserted in the borehole for these purposes include a 6 5/8-inch O.D. pipe and a 2 3/8-inch O.D. pipe, respectively. The remaining open volume azound the pipes is filled with grout. The pad for the bin consists of a solid one-foot thick footer and fow concrete pillars. The total concrete volume is approximately 11 cubic yazds. Surface Facilities The Foidel Creek Mine portal area is located in a partially backfilled final cut. This excavation was filled to an elevation of 6,860 feet and leveled. Before fill materials were placed in the pit, aloes-permeability barrier was established against the highwall to isolate the spoils aquifer from the underground mine workings. Approximately 20,000 bcy of surficial materials high in clay and silt were required to construct a barrier berm about 15 fee[ in thickness. An average depth of 1.5 feet of soil materials was removed from an azea north of the portal pit to construct the barrier. The suitability of the materials selected for the bamer is illustrated by the following textural analysis of soil samples collected from the designated salvage site: TR07-59 2.05-53 03/26/07