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In order to comply with new Mine Atmosphere Control (MAC) regulations, under the jurisdiction of the Mine <br />Safety and Health Administration (MSHA), and minimize surface disturbance, TCC proposes to drill and case up to <br />two MAC boreholes from the surface of the cuttings collection pit into the bleeder entries (approximately 1,000 <br />feet). The 30 -inch diameter borehole(s) would be drilled using a conventional down -hole rotary drill -rig and <br />cuttings will be collected in a portapit. Surface casing will be set and grouted to bedrock, and steel borehole casing <br />with a nominal inside diameter of 24 inches will be set and the annulus between the casing and the borehole will be <br />fully grouted to both stabilize the casing and seal it off from potential groundwater infiltration. At the cuttings pit <br />liner interface, quick -set grout will be injected above and below the liner to seal the liner where it is penetrated by <br />the surface casing. Cover material will be removed from a portion of the cuttings pit, and borehole cuttings will be <br />transferred to this area to dry, and will then be spread and compacted. On completion of the borehole(s), the cover <br />material will be replaced and stabilized by seeding with a temporary cover. The stockpiled cuttings will be used to <br />backfill the MAC borehole(s) during final reclamation. A methane drainage pipeline and/or nitrogen injection <br />pipeline will be installed within the cased MAC borehole, and connected to one or more manifolded pipe systems <br />underground which will connect to sealed gob areas. 'At the surface, an 8 -foot diameter culvert manhole may be <br />installed around the cased MAC borehole(s) as a well -head, with appropriate grounding and lightning protection to <br />meet MSHA requirements. The fixed pipeline(s) will connect at the surface to a portable skid - mounted methane <br />drainage pump and/or skid - mounted nitrogen generator. Required power for this installation will be provided by <br />dropline from the existing powerpole, and the area will be fenced for security. Installation details are shown by the <br />design drawings in Exhibit 49Q. <br />6 -North Mains Ventilation Shaft (TR05 -48 TR08 -61 MR06 -208 MR06 210 MR06 212 MR07 218) <br />An additional intake ventilation shaft is necessary to maintain effective ventilation of active mining areas in the <br />northwest mining district and future west mining district. The new ventilation shaft will be located in Section 17, <br />TSN, R86W on a ridge northwest of the Northwest Mains Ventilation Shaft and fan, as shown on Maps 23 and 23B. <br />Site - specific investigations required for design and permitting of the new ventilation shaft included a cultural <br />resource survey of potential disturbance areas, soil and foundation characterization as the basis for shaft pad and <br />access road design, and completion of a wetland/AVF survey for the shaft pad and access road. The cultural <br />resource survey was conducted by Metcalf Archaeological Consultants, the engineering soils characterization by <br />Northwest Colorado Consultants, and the soils /wetland/AVF survey by Habitat Management, as described in <br />Section 2.04. Development, construction, and installation of the intake ventilation shaft (Exhibit 49A, Figures <br />EX49A -Fl through F4 and Maps EX49A -Ml through M3, and Exhibits 49E and 49N) involve the following <br />sequential activities, as briefly described in the following sections: <br />• Completion of environmental and engineering investigations <br />• Placement of disturbed area markers <br />• Marking of wetland buffer zone <br />• Temporary drainage and sediment control measures <br />• Recovery and stockpiling of available topsoil <br />• Installation of drainage and sediment control structures <br />• Construction of an access road and site preparation for shaft pad <br />• Drilling and casing of seven (7) boreholes for: <br />- 3 power boreholes <br />- 1 water borehole <br />- 1 air compressor borehole <br />- 1 rockdust borehole <br />- 1 bulk - material drop borehole <br />• Construction of shaft collar structure and temporary drilling equipment pad <br />• Conventional blind sink excavation and casing operations <br />• Driving of additional entries to the south of the existing 6 -North Main entries <br />• Installation of electrical sub - station and extension of power distribution line <br />f � • Fabrication of Million - Gallon Tank for mine water storage <br />- • Installation of Rock -Dust Tank and Compressor <br />TR09 -66 2.05 — 45.6a 02/17/09 <br />