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The proposed shaft pad azea is approximately 280' squaze (1.8 acres) and the associated access road corridor is approximately 3,800' long with a finished top width of 22 feet (road corridor 30 feet wide). See Exhibit 25 S, NW Mains Ventilation Shaft Access Road Design, for details on the road. Approximately 2,000 feet of the access road crosses upland areas, with the remaining 1,800 feet crossing lowland azeas where road construction will involve removal of any lazge vegetation and placement of geotexti]e and road fill over the in-place soils. Given an average topsoil depth of approximately 6" in the upland area and a total disturbance azea of approximately 1.4 acres, approximately 1,111 CY of topsoil will be salvaged from the road corridor, and 1,452 CY from the pad. The topsoil from these areas will either be windrowed adjacent to the road comdor or placed in stockpile adjacent to the shaft pad for future reclamation use. The topsoil salvage volumes are indicated on Table 49A. Seeding with the topsoil stockpile stabilization seed mixture will stabilize the windrowed and stockpiled topsoil. Following topsoil removal, required drainage and sediment control structures will be constructed or installed. These structures include designed culverts for the road crossing of Fish Creek (see Exhibit 8R, Fish Creek Culvert Design, NW Mains Ventilation Shaft) and road crossings of smaller ephemeral drainage channels; discharge control structure (rock check dam) at the downgradient limit of the shaft pad, and a temporary diversion ditch around the up-gradient perimeter of the shaft pad. The drainage from the shaft pad is addressed under a Small Area Exemption (SAE) section of the permit, as it is a relatively small (approximately 1.8 acres), grave]-surfaced and or reclaimed area. The access road follows relatively level terrain and will be gravel surfaced, so access road drainage control requirements are minimal. All drainage calculations and documentation is provided in Exhibit 8S, the SAE demonstration is provided later in this section, and the drainage structures are shown on Map 24. The SAE demonstration includes ditch sizing for the upland diversion ditch and road ditch. • The access road into the shaft pad crosses Fish Creek, and TCC will place "Buffer Zone" signs at the boundary of the stream crossing disturbance. Except for the disturbance associated with the stream crossing no further activity is planned within the Buffer Zone boundary. Construction of the ventilation shaft access road involves topsoil recovery and windrowing or stockpiling, installation of required drainage structures, scarification and re-compaction of surface materials, placement of geotextile in selected azeas, and placement and compaction of approximately 8" of pit-run gravel and 3" of road-base material. The access road surface will be approximately 22' wide and will be graded and crowned to promote effective drainage. Road construction requires minimal cut, and limited fills in the azea of the Fish Creek drainage crossing. Fill slopes will be graded to a 3H:1 V and stabilized by seeding with the topsoil stockpile stabilization seed mixture. Prepazation of the ventilation shaft pad involves topsoil recovery and stockpiling, installation of required drainage structures, grading and compaction to establish a level pad working area, excavation of mud pits for drilling of the shaft pilot hole, temporary stockpiling of the excavated material, and placement of gravel surfacing material to control dust and sediment from the pad azea. Mud pits will be approximately 20' x 20' x 8' deep and aze sized to contain all drilling fluids. In the event unanticipated ground water flow into the boring is encountered then the pits maybe enlazged or additional pits excavated to handle the flow. The ventilation shaft pilot hole will be drilled using a reverse circulation drill rig to drill a 14" nominal diameter pilot hole from the surface to a depth of approximately 1450'. The shaft collaz azea will be excavated to a depth of approximately 20', a collar liner, consisting of steel ring beams and liner plate will be placed, and the annulus between the liner and the collaz excavation cemented. A temporary head- . frame will be erected on the shaft collar structure over the pilot hole to support and handle the shaft boring equipment. The shaft boring drive unit will be installed on the shaft collaz structure in prepazation for shaft boring operations. During drilling, all drilling fluids will be contained in the excavated mud pits MR 02-179 2.05-45.1 08/06/02