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The grouted steel liner will serve to isolate the Twentymile Sandstone from the Wadge Overburden. As previously <br />noted, TCC plans to pressure -grout the Twentymile Sandstone to minimize seepage to the shaft. This will help <br />assure that, after final closure, groundwater from this unit will be confined and not seep down the inside of the <br />shaft. Following completion of shaft boring and casing operations and removal of equipment from the site, the <br />emergency hoist equipment will be erected on either the previously constructed or a new concrete pad. Average <br />pad thickness will be 1-2 feet, and total pad surface area will be approximately 800 s£ A fence will be constructed <br />to enclose the surface collar and emergency hoist installation. A pre -fabricated propane -fired shaft heater and <br />ducting will be installed on the existing concrete collar structure and connected to a skid -mounted propane tank and <br />a buried electrical cable. Two additional powerpoles on the shaft pad will support a drop -line from the nearby <br />Yampa Valley Electric Association power distribution line. Following commissioning, the shaft pad site and access <br />road will be cleaned -up and surface areas graded and dressed. <br />In order to minimize potential environmental and aesthetic impacts associated with the 18 -Right ventilation shaft <br />and emergency hoist installation, surface drainage at the shaft site will be handled by two (2) up -gradient diversion <br />ditches, two (2) down -gradient drainage ditches, the use of 20 -inch diameter sediment logs around the lower <br />portion of the topsoil stockpile, the use of Curlex single net (Curlex I) erosion control blankets over seeded cut and <br />fill slopes, the combination of a rock filter (2 -ft rock berm) and grass filter, and gravel surfacing under an SAE <br />(Refer to Exhibit 8T for SAE detail). Drainage from the other topsoil stockpiles will be addressed by upslope <br />diversion ditches to route upgradient run-on around the piles, silt fence or wattles at the downslope toe of the piles, <br />and rock check dams where the upslope drainage meets the designed road ditches. The limited road drainage will <br />be handled by a designed road ditch and drainage structures. Active use areas will be graveled to control dust and <br />drainage, other disturbed areas (including topsoil stockpiles) will be stabilized with temporary vegetation, and any <br />structures will be painted in neutral earth -tone colors to blend with the natural surroundings. <br />As shown on Map 23, additional entries will be driven at the back of the 18 -Right gate road to the east to connect <br />with the ventilation shaft. These entries will be needed to maximize the efficiency of the ventilation system. The <br />entries will be driven in the same manner as is used in TCC's development work, i.e. continuous miners and shuttle <br />cars. <br />In order to comply with new Mine Atmosphere Control (MAC) regulations, under the jurisdiction of the Mine Safety <br />and Health Administration (MSHA), and minimize surface disturbance, TCC proposes to drill and case up to two <br />MAC boreholes from the surface of the cuttings collection pit into the bleeder entries (approximately 1,000 feet). The <br />30 -inch diameter borehole(s) would be drilled using a conventional down -hole rotary drill -rig and cuttings will be <br />collected in a portapit. Surface casing will be set and grouted to bedrock, and steel borehole casing with a nominal <br />inside diameter of 24 inches will be set and the annulus between the casing and the borehole will be fully grouted to <br />both stabilize the casing and seal it off from potential groundwater infiltration. At the cuttings pit liner interface, <br />quick -set grout will be injected above and below the liner to seal the liner where it is penetrated by the surface casing. <br />Cover material will be removed from a portion of the cuttings pit, and borehole cuttings will be transferred to this area <br />to dry, and will then be spread and compacted. On completion of the borehole(s), the cover material will be replaced <br />and stabilized by seeding with a temporary cover. The stockpiled cuttings will be used to backfill the MAC <br />borehole(s) during final reclamation. A methane drainage pipeline and/or nitrogen injection pipeline will be installed <br />within the cased MAC borehole, and connected to one or more manifolded pipe systems underground which will <br />connect to sealed gob areas. At the surface, an 8 -foot diameter culvert manhole may be installed around the cased <br />MAC borehole(s) as a well -head, with appropriate grounding and lightning protection to meet MSHA requirements. <br />The fixed pipeline(s) will connect at the surface to a portable skid -mounted methane drainage pump and/or skid - <br />mounted nitrogen generator system consisting of the nitrogen generator, two air compressors, a diesel generator, and a <br />control building. Required power for this installation will be provided by dropline from the existing powerpole, and <br />the area will be fenced for security. Installation details are shown by the design drawings in Exhibit 49Q. <br />6 -North Mains Ventilation Shaft (TR05-48, TR10-73, MR06-208, MR06-210, MR06-212, MR07-218 MR09- <br />236) <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 />MR 11-259 2.05-45.7 11/17/11 <br />