2008-10-03_PERMIT FILE - C1982056A (4)

Home Browse Search

Underground Utilities Proiect Components: Concurrent with road construction, a 69-KV power distribution line was extended from the existing substation at the Northwest Mains fan location to apad-mounted transformer at the 6 North Mains shaft site. The power distribution dine is approximately 3,130 feet long with a total of approximately 14 powerpoles and' is located adjacent to the proposed access road and within the 50-foot road corridor from road centerline. In conjunction with the 6-North Mains shaft project and extension of the power distribution line, TCC also proposes to construct on the shaft pad a high voltage substation with three power borehole drops, a compressed air station with borehole drop, arock-dust tank station with borehole drop, a bulk material borehole drop and a water borehole drop for the continued development and mining of the Northern and Western Mine Districts. The boreholes were drilled to a nominal 13-inch diameter. Water for drilling operations was either trucked-in by tanker or drawn from Fish Creek using a portable pump (under TCC's Boettler Ditch water right - 144 cfs). The cuttings were disposed of in the collection pit. Steel Schedule-40 or -80 pipe was placediin each of the nominal 13-inch diameter holes, and the annulus was fully grouted. The. power distribution component includes construction of the 69 KV powerline, approximate 150 by 150-foot substation area, switchgear building, grounding bed and three nominal 13-inch diameter boreholes from the surface to the underground workings at the proposed intake shaft pad above the 6 North Main entries. The substation area consists of powerpoles for powerline termination, transformer pads, and an approximate 14 x 30-foot prefabricated metal building with foundation, and grounding bed. There are three fuse disconnects and three gang-operated disconnects between the powerpole terminations and the transformers. The metal building houses the switchgear for the power feed from the transformers to the power cables that feed into the power borehole. The grounding bed, located outside of the shaft pad area, consists of copper rods buried in trenches at a depth of approximately 5 feet. In order to hang the power cables in the holes, a steel structure(s) was constructed over the three cased holes. This structure(s) is a metal beam(s) and legs, bolted to a concrete footer(s).. The beam(s) will be either 14 feet or 10 feet (up to three) in length, and the legs are approximately 6.5 or 8 feet high. The footer(s) is approximately 4 x 4 x 4 feet. The 14-foot beam structure extends over all three boreholes. The 10-foot beam structures will be placed over individual or paired borings, if used. On completion and casing of the borings, a 7 x 10 x 5-foot pad was poured around the three power-drop boreholes. The .air compressor component includes construction of a pad, a compressor building, installation of an existing compressor, installation of an electrical power supply for the compressor, and drilling of a nominal 13-inch borehole from the surface to the underground workings from the shaft pad above the 6-North Main entries. Drilling of the borehole was covered by the TROS-48 submittal. Details for the concrete pad and compressor support facilities will be submitted for review and approval as a Minor Revision, prior to installation. The rock dust component includes construction of a pad, installation of an existing rock dust storage tank, installation of an electrical power supply for the rock dust tank, and drilling of a nominal 13-inch borehole from the surface to the underground workings from the shaft pad above the 6-North Main entries. Drilling of the borehole was covered by the TROS-48 submittal. Details for the concrete pad and rock dust storage and delivery facilities will be submitted for review and approval as a Minor Revision, prior to installation. The bulk material component includes construction of a pad, installation of a bulk material hopper, and drilling of a nominal 13-inch borehole from the surface to the underground workings from the shaft pad above the 6-North Main entries. Drilling of the borehole was covered by the TROS-48 submittal. Details for the concrete pad and bulk storage and transfer facilities will be submitted for review and approval as a Minor Revision, prior to installation. The water component includes construction of a reinforced concrete pad and footers, installation of a water tank (6MN Million-Gallon Tank - MR06-210) and associated pumping installation, and drilling of a nominal 13-inch borehole from the surface to the underground workings from the shaft pad above the 6-North Main entries. Drilling of the borehole was covered by the TROS-48 submittal. TCC proposes to construct a steel water tank 85 feet in diameter and 24 feet high designed to hold one million gallons. The tank will rest on a reinforced concrete .foundation consisting of aspread-footer, stem wall, and slab floor supported by concrete pilings. Preparation of the tank foundation area will involve grading, compaction, and excavation for the support pilings and spread-footer. TR07-61 2.05 - 45.6e 07/14/07