PERMFILE139112 - Laserfiche WebLink

Home Browse Search

i.e. continuous miners and shuttle cazs. Following commissioning of the shaft, the shaft pad site and access road will be cleaned-up and surface areas graded and dressed. No. 7 North Escape Shaft (Section 20, TSN, R86V1~ A 1,066 foot escape borehole shaft was constructed into the No. 7 entry of North Mains to allow emergency evacuation of personnel from the development sections of the 9-Right and 10-Right gateroads. The construction of the shaft utilized raise drilling techniques. It is anticipated that the escape shaft will be utilized for approximately ten yeazs. The site is shown on Figure 23, General Location of Escape Shaft. The drilling of the shaft resulted in minimal surface disturbance. A drill pad approximately 200 x 200 feet was constructed at the resulting site in 1,450 CY of cut and fill. Available topsoil was salvaged and stockpiled for future reclamation of the site immediately northeast of the drilled pad. Approximately 18 inches of topsoil derived from Cochetopa Loam is available for salvaging (222 CY). Casing and other drilling supplies were stockpiled on the borehole pad. After topsoil removal, two mud pits 10 x 10 x 7.5 feet were dug adjacent to the drillhole. Drilling fluids and cuttings were discharged into the adjacent pits, allowing settling in one pit, with water decanting into the adjacent pit. Drilling muds were used during the course of drilling the surface collaz and pilot hole. The surface collaz was approximately 5.0 feet in diameter, and the pilot hole was 11 inches in diameter. The collaz was comprised of two components; a surface concrete pad and a liner or casing that extends to bedrock. A concrete centering base is at the bottom of the liner. The concrete pad was poured around the liner and was approximately 14x 10 x 2 feet, however, the liner extends through the pad, reducing the amount of concrete needed to construct the pad. Approximately 8.9 CY of concrete was required to construct the pad. After the collaz and liner were in place and the pilot hole was completed, raise-boring methods were used to complete the hole. The hole was reamed to a final diameter of 4.33 feet and a 48-inch diameter steel casing was cemented in place from 50 feet below the bottom of Twentymile Sandstone to the top of the concrete centering pad. The remainder of the casing below the cement hangs in the hole. The hole is approximately 1,100 feet in depth. The 4-foot diameter casing extrudes 4 to 6 inches out of the concrete surface pad. A cap to regulate intake air flow was installed. A fence was installed azound the drill pad to prevent access by cattle, after completion of the hole. Access was derived from an existing light-use road running up to an old electrical borehole. A series of culverts were placed under the existing road as shown on Figure 23, General Location of Escape Shaft. The design for the culverts can be found in Exhibit 8D, Escape Shaft/Light-Duty Road Culvert Design. TCC constructed an additional 25-foot wide road at a 4 percent grade to access the site. The 1,300-foot long road is graveled with 0.5 feet of 6-inch pit-run gravel. Buffalo Force Fau Silencer (MR 03-1871 A new silencer will be installed on the Buffalo fan at the NW Mains Ventilation Shaft location. Installation of the silencer will require construction of foundations utilizing concrete piers and concrete grade beams. The foundation will require eight concrete piers (6-inch radius x 20 feet deep) and then placement of two concrete grade beams (12" x 2' x 31') on top of the piers. The concrete grade beams will be reinforced with three #5 rebar, and #4 stirrups spaced at 8 inches on center within 3 feet of the piers, and spaced at 16 inches on center at all other locations. TROS-48 2.05-45.7 09/05/05