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promote effective drainage. Road construction requires minimal cut and limited fill, so the actual road <br />disturbance area wilt average approximately 35 feet wide. Cut slopes will be established at a maximum of <br />1.SH:1V and fill slopes will be graded to 2H:1V or less, with all disturbed slopes to be stabilized by <br />seeding with the topsoil stockpile stabilization seed mixture. For permitting purposes, a road disturbance <br />corridor 100 feet wide has been defined as encompassing all project-related activities, including road <br />construction and topsoil stockpiling/windrowing. <br />Preparation of the ventilation shaft pad will involve topsoil recovery and stockpiling, installation of <br />required drainage structures, grading and compaction to establish a level pad working azea, excavation of <br />a collection pit for blind drilling of the shaft pilot hole and shaft, haulage or stockpiling of the excavated <br />bon•ow material, and placement of gravel surfacing material to control dust and sediment from the pad <br />area. Excavated borrow material from the collection pit will be hauled to the neazby Fish Creek Loadout <br />for use in final reclamation. The collection pit will be approximately 100 x 200 x 10 feet and is sized to <br />contain all drilling fluids and cuttings. In the event unanticipated ground water flows are encountered, <br />they would occur during drilling of the pilot hole when the collection pit would have significant excess <br />capacity. The combination of excess capacity and flow controls should be adequate to prevent any oft= <br />site dischazge. Facility construction details and configuration are illustrated by Maps 15-50 and 1 W-50 in <br />Exhibits 16C and 16D. The cuttings pit and associated foundation azea will be inspected during topsoil <br />stripping, placement of the liner, and temporary closure, on completion of shaft boring operations. As- <br />built certification will be provided to the CDMG prior to cuttings placement and following temporary <br />closure. <br />Primary Method of Construction -Blind Drillin <br />Prior to the beginning of the blind drilling process, a pressurized pre-grout operation utilizing up to ten <br />small diameter (2") holes, up to approximately 400 feet deep azound the shaft perimeter will be <br />considered and undertaken, as needed, to limit groundwater flows between the shaft and the formations. <br />Individual grout holes would be drilled and a cement grout would be pumped under pressure into each <br />borehole before completing the next hole, to seal any wet zones encountered. Each borehole would be <br />filled with grout and allowed to set-up, effectively sealing the borehole and any fractures or voids in the <br />grouted formation(s). Any surface casing extending above ground surface will be cut-off flush with or <br />below natural Bound level. <br />If needed and once the pre-grout operation is completed, a shaft collar will be excavated to an <br />approximate 10-foot diameter to competent rock at a depth of approximately 10-15 feet. Material from <br />the collar excavation will be placed within and on one end of the cuttings pit. A surface casing <br />approximately 8 feet in diameter (inside) and large enough to accept the shaft casing and drilling tools <br />will be installed in the shaft collaz. This surface casing will be either steel casing grouted in-place or cast- <br />in-place concrete. A 48 by 24 foot concrete T-shaped pad will then be poured to accommodate the <br />drilling and casing equipment. Specialized blind drilling equipment in the form of an A-leg derrick will <br />be used to drill the pilot hole and excavate the shaft. A nominal 17-1/Z-inch pilot hole will then be drilled <br />to an approximate depth of 1,000 feet and surveyed to determine vertical shaft deviation and location <br />underground for mine entry tie-ins. The pilot hole will then be reamed to a nominal diameter of 7.5 feet <br />to accommodate the final steel liner. The reaming technique utilizes an inverted disc cutter equipped <br />hemispherical raise bore head to cut the rock. During the drilling of the pilot hole and the 7.5' diameter <br />excavation, all cuttings will be removed from the excavation using an airliR system, with water (reverse <br />circulation) being the circulation media. Supplemental water, for drilling and to adjust the density of the <br />drilling medium, may be supplied, as needed, by a small portable pump drawing from Fish Creek under <br />TCC's existing water rights. The cuttings will be placed in a 200 x 100 x 10 foot, lined temporary mine, <br />MROS-194 2.05-45.5 07/2/05 <br />