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The total road disturbance will be approximately 1.6 acres, and the maximum pad disturbance (including cut/fill <br />slopes and diversion ditches) will be approximately 2.3 acres. <br />The proposed pad and road locations are on a low -gradient sidehill, so upgradient drainage will be limited. The <br />limited amount of drainage from upgradient areas will be routed under the road through culverts or intercepted and <br />routed around the borehole pad by a small perimeter diversion ditch on the east, south, and west sides of the pad, <br />utilizing small rock -lined sediment traps to control discharge and sediment. Drainage from the borehole pad areas <br />will be controlled under a Small -Area Exemption, with gravel surfacing on the pad and road to control runoff and <br />sediment, stabilization of cut/fill areas with temporary revegetation seeding, control of runoff from outslope areas <br />for the original by the perimeter ditch and sediment traps, and control of drainage from the new pad by the existing <br />down -gradient control features (wattles of equivalent). Drainage designs for the culverts and diversion ditch are <br />provided in Exhibit EX49EE. <br />Borehole completion will involve drilling, installing, and grouting steel surface casing in place to a maximum depth <br />of approximately 60 feet (dependent on the ground conditions encountered). The boreholes will then be advanced, <br />to depth to intercept the Wolf Creek mine workings (original boreholes) and Wadge mine workings (additional <br />boreholes). Water, drilling fluids, and cuttings will be contained within one or more excavated pits or portable steel <br />tanks (porta-pits) on the borehole pad. For the original boreholes, the surface casing for the larger utility borehole <br />will be 32 -inches in diameter. if dry, this borehole will be drilled to 22 -inches and cased to 16 -inches, or if wet, 30 - <br />inches and cased to 24 -inches. The surface casing for the smaller utility borehole will be 24 -inches. The smaller <br />utility borehole will be drilled to 22 -inches and cased to 16 -inches if wet. If dry, this borehole will be drilled to <br />13.75 -inches. A 6.675 -inch and 3.5 -inch carrier pipe will be placed and grouted in either the 16 -inch casing (wet) <br />or 13.75 inch (dry) borehole. The larger carrier pipe may be used for grouting, material transfer, or other utility <br />needs. The smaller carrier pipe may be used as a power drop or for a communications line(s). The two additional <br />boreholes will be drilled to a maximum diameter of 18 -inches and a maximum depth of 990 -feet, and cased to a <br />maximum diameter of 14 -inches. <br />Power to the 9 -East Utility Borehole Installation will be provided by a branch -line from the existing nearby <br />powerline, extending from 990 to 1,700 feet, depending on which pad location is selected. Powerline construction <br />will require placement of from 14 to 34 power -poles, dependent on which pad location is selected and power -pole <br />spacing (50 to 75 feet). A switch and transformer on the Yampa valley Electric line at the connection with the <br />branch -line, and a drop -line at the pad location will provide power to the portable skid -mounted exhauster units on <br />the original pad and up to two wheel -mounted exhausters on the new boreholes. Power for the two additional <br />boreholes will be provided by a drop -line on the existing pad and by a short (approximately 500 -foot w/a maximum <br />of two poles) extension from the existing line for the new pad. The 9 -East Utility Borehole Installation will remain <br />in place until it is no longer needed to support ongoing operations (estimated life of approximately 3 -years), and <br />will then be reclaimed. Reclamation will involve plugging and sealing the boreholes, removing the powerline, <br />regrading the pads and road, drainage reestablishment, soil material replacement, and reseeding. <br />MR17-304 2.05 — 45.31 01/12/17 <br />