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from these areas will either be windrowed adjacent to the road corridor or placed in stockpile adjacent to the shaft <br />pad for future reclamation use. The topsoil salvage volumes are indicated on Table 49A. Seeding with the topsoil <br />stockpile stabilization seed mixture will stabilize the windrowed and stockpiled topsoil. <br />Following topsoil removal, required drainage and sediment control structures will be constructed or installed. <br />These structures include designed culverts for the road crossing of Fish Creek (see Exhibit 8R, Fish Creek Culvert <br />Design, NW Mains Ventilation Shaft) and road crossings of smaller ephemeral drainage channels; discharge control <br />structure (rock check dam) at the downgradient limit of the shaft pad, and a temporary diversion ditch around the <br />upgradient perimeter of the shaft pad. The drainage from the shaft pad is addressed under a Small Area Exemption <br />(SAE) section of the permit, as it is a relatively small (approximately 1.8 acres), gavel-surfaced and or reclaimed <br />area. The access road follows relatively level terrain and will be gravel surfaced, so access road drainage control <br />requirements are minimal. All drainage calculations and documentation is provided in Exhibit 8S, the SAE <br />demonstration is provided later in this section, and the drainage structures are shown on Map 24. The SAE <br />demonstration includes ditch sizing for the upland diversion ditch and road ditch. <br />The access road into the shaft pad crosses Fish Creek, and TCC will place "Buffer Zone" signs at the boundary of <br />the stream crossing disturbance. Except for the disturbance associated with the stream crossing no further activity is <br />planned within the Buffer Zone boundary. <br />Construction of the ventilation shaft access road involves topsoil recovery and windrowing or stockpiling, <br />installation of required drainage structures, scarification and re-compaction of surface materials, placement of <br />geotextile in selected areas, and placement and compaction of approximately 8" of pit-run gravel and 3" of road- <br />base material. The access road surface will be approximately 22' wide and will be graded and crowned to promote <br />effective drainage. Road construction requires minimal cut, and limited fills in [he area of the Fish Creek drainage <br />crossing. Fill slopes will be graded to a 3H:1V and stabilized by seeding with the topsoil stockpile stabilization <br />seed mixture. Preparation of the ventilation shafr pad involves topsoil recovery and stockpiling, installation of <br />required drainage structures, grading and compaction to establish a level pad working area, excavation of mud pits <br />for drilling of the shafr pilot hole, temporary stockpiling of the excavated material, and placement of gravel <br />surfacing material to control dust and sediment from the pad area. Mud pits will be approximately 20' x 20' x 8' <br />deep and are sized [o contain all drilling fluids. In the event unanticipated ground water flow into the boring is <br />encountered then the pits may be enlarged or additional pits excavated to handle the flow. <br />The ventilation shaft pilot hole will be drilled using a reverse circulation drill rig to drill a 14" nominal diameter <br />pilot hole from the surface to a depth of approximately 1450'. The shaft collar area will be excavated to a depth of <br />approximately 20', a collar liner, consisting of steel ring beams and liner plate will be placed, and the annulus <br />between the liner and the collar excavation cemented. A temporary head-frame will be erected on the shaft collar <br />structure over the pilot hole to support and handle the shaft boring equipment. The shaft boring drive unit will be <br />installed on the shaft collar structure in preparation for shaft boring operations. During drilling, all drilling fluids <br />will be contained in the excavated mud pits and drilling fluids are generally re-circulated. Shaft boring and casing <br />of the approximate 20' diameter ventilation shafr are conducted as separate operations. Asurface-mounted drive <br />unit is used to turn a rotary cutting head attached to a shaft extending from the surface through the pilot hole, and a <br />hoist on the temporary headframe is used to maintain continuous upward pressure on the cutter head. As boring <br />progresses, the cuttings are dropped down the shaft bore and are recovered and then transported as follows: they <br />may be placed in mined-out areas underground, they may be slurried to the EMD sump, or they may be stored on <br />the ground in the previously approved overburden stockpile, south of [he old pi[. Slurrying would require <br />installation of an underground line. The slurry would be pumped behind the seals in 7, 9 or ]0 Right. If the <br />underground development waste cuttings are not placed underground they will be transported to the surface via the <br />existing conveyance system and then will be stored south of [he old pit. The cuttings volume will be approximately <br />21,000 cy (16,862 cy swelled by 25%). The cuttings will discharge off of the existing rock belt where they will be <br />loaded into trucks and hauled to [he previously approved overburden storage area (see Map 24 for location). This <br />overburden storage area is in a <br />MR 02-176 2.05-45.1 02/20/02 <br />