2010-06-04_PERMIT FILE - C1982056A (9)

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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, a rockdust 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 placed in 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 rock -dust component includes construction of a 22 x 24 x 1 foot reinforced concrete slab foundation with four 2 -foot diameter 9.5 foot reinforced concrete piers, installation of an existing 36 -foot high rock -dust storage tank, 00 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 TR05 -48 submittal. The rock -dust tank has a capacity of 2,440 cubic feet, or 100 tons of rock - dust. The tank will deliver rock -dust to the borehole through an air slide angled at 10 degrees. Tank aeration will be provided by the compressor. The tank will be monitored by electronic controls and strain gauges. Electricity will be supplied from the 6 -Main North substation. An electrical line will run from the tank down an existing electrical borehole to controls underground. The air compressor component includes construction of a reinforced concrete slab foundation with stem wall and footer extending 4 -foot below grade, a 30 x 50 x 12 foot compressor building, installation of existing compressors, installation of an electrical power supply for the compressors, installation of Polo Citrus tanks, 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 TR05 -48 submittal. The compressor building will house two air compressors, two dryers, two 5,000 gallon Polo Citrus tanks, and electrical and control equipment for the systems within the building. The building will be constructed of steel and rest on a designed steel - reinforced concrete foundation. It will be supplied power from the 6 -Main North substation and will be insulated and heated. The Polo Citrus tanks will be enclosed by a containment system capable of holding in excess of 5,000 gallons. 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 TR05 -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 and associated pumping installation, drilling of a nominal 13 -inch borehole from the surface to the underground workings from the shaft pad above the 6 -North Main entries, and construction of the 6MN Mine Water Storage Reservoir. Drilling of the borehole was covered by the TR05 -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 a spread- footer, stem wall, and slab floor supported by concrete 2.05 — 45.6e 07/28/09 TR06 -57