Laserfiche WebLink
disturbed areas (including topsoil stockpiles) will be stabilized with temporary vegetation, and any structures will <br />be painted in neutral earth-tone colors to blend with the natural surcoundings. <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 />No. 7 North Escape Shaft (Section 20, TSN. R86 W <br />A 1,066 foot escape borehole shafr was constructed into #7 entry of North Mains to allow emergency evacuation of <br />personnel from the development sections of the 9 Right and 10 Right gateroads. The construction of the shaft <br />utilized raise drilling techniques. It is anticipated that the escape shaft will be utilized for approximately ten years. <br />The site is shown on Figure 23, General Location of Escape Shaft. <br />The drilling of the shafr resulted in minimal surface disturbance. A drill pad approximately 200' x 200' was <br />constructed at the resulting site in 1,450 CY of cut and fill. Available topsoil was salvaged and stockpiled for <br />future reclamation of the site immediately northeast of the drilled pad. Approximately 18" of topsoil derived from <br />Cochetopa Loam is available for salvaging (222 CY). Casing and other drilling supplies were stockpiled on the <br />borehole pad. <br />After topsoil removal, two mud pits with dimensions of 10' x 10' x 7.5' were dug adjacent to the drill hole. <br />Drilling fluids and cuttings were discharged into the adjacent pits, allowing settling in one pit with water decanting <br />into the adjacent pit. Drilling muds were used during the course of drilling the surface collar and pilot hole. The <br />surface collar was approximately 5.0 feet in diameter, and the pilot hole was I 1 inches in diameter. <br />The collar was comprised of two components; a surface concrete pad and a liner or casing that extends to bedrock. <br />A concrete centering base is at the bottom of the liner. <br />The concrete pad was poured around the liner and was approximately 14'x 10' x 2'. However, the liner extends <br />through the pad, reducing the amount of concrete needed to construct the pad. Approximately 8.9 CY of concrete <br />was required to construct the pad. After the collar and liner are in place and the pilot hole was completed, raise <br />boring methods were used to complete the hole. The hole was reamed to a final diameter of 4.33 feet and a 48 inch <br />diameter steel casing was cemented in place from 50 feet below the bottom of Twentymile Sandstone to the top of <br />the concrete centering pad. The remainder of the casing below the cement hangs in the hole. The hole is <br />approximately 1,100 feet in depth. The 4' diameter casing extrudes 4 to 6 inches out of the concrete surface pad. A <br />cap to regulate intake air flow was installed. A fence was installed around the drill pad to prevent access by cattle, <br />after completion of the hole. <br />Access was derived from an existing light-use road running up to an old electrical borehole. A series of culverts <br />were placed under the existing road and their locations shown on Figure 23, General Location of Escape Shaft. The <br />design for the culverts can be found in Exhibit 8D, Escape Shaft/Light-Duty Road Culvert Design. TCC <br />constructed an additional 25-foot wide road at a 4 percent grade to access the site. The 1,300-foot long road is <br />graveled with 0.5 feet of 6-inch pit run gravel. <br />Buffalo Foree Fan Silencer (MR 03-187 <br />A new silencer will be installed on the Buffalo fan at the NW Mains Ventilation Shaft location. Installation of the <br />silencer will require construction of foundations utilizing concrete piers and concrete grade beams. The foundation <br />will require eight concrete piers (6-inch radius x 20 feet deep) and then placement of two concrete grade beams <br />(12" x 2' x 31') on top of the piers. The concrete grade beams will be reinforced with three #5 rebar, and #4 <br />stirrups spaced at 8 inches on center within 3 feet of the piers, and spaced at 16 inches on center at all other <br />locations. <br />MROS-192 2.05 - 45.6 03/22/05 <br />