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The proposed utility borehole installation will require construction of approximately 1.25 mile of new light -use <br />road from the existing 17LT access point to the borehole pad location, and construction of a new borehole pad <br />(approximately 200 x 300 ft.). The 16LT Utility Borehole installation will consist of the new light -use road and <br />borehole pad; adjacent soil material stockpiles, and the lined and grouted borehole extending into the active mine <br />workings. The road disturbance corridor will be 75 feet wide, although the actual road surface will only be <br />approximately 25-35 feet wide. The total road disturbance area will be approximatelyl1.4 acres, and the pad <br />disturbance area (includes cut/fill slopes and soil stockpiles) will be approximately 2.2 acres. <br />Site-specific investigations required for design and permitting of the new utility borehole installation include a cultural <br />resource survey and wildlife consultation. The cultural resource survey results are summarized by the survey report <br />provided in Exhibit 6T, and a wildlife consultation letter is included in Exhibit 23C. The perimeter of all areas to be <br />disturbed will be clearly marked and construction drainage control measures (silt fences or wattles) will be in place <br />prior to disturbance. In order to reestablish effective vegetative cover during site reclamation, TC will recover and <br />stockpile a maximum of 1.0 foot of soil material from the road and pad disturbance areas. A maximum of <br />approximately 12,200 cy of soil will be recovered and stockpiled from the road disturbance area, and approximately <br />3,600 cy from the pad area. Natural vegetative materials incorporated into the salvaged soil materials and seeding <br />with the soil stockpile stabilization seed mixture will assist in stabilizing the stockpiled soil material and preventing <br />erosion or loss of soil material. <br />Following soil recovery, appropriate designed drainage and sediment control structures will be constructed or <br />installed. A total of nine culverts (each approximately 30 feet long) will be installed along the light -use road to <br />pass natural drainage under the road, and the road surface will be graveled to provide all-weather access and control <br />runoff and sediment generation. The two culverts south of the 17 -Left Pad and the culvert adjacent to the 16 -Left <br />Pad are designed culverts, while the remaining culverts have limited contributing drainage areas, address road <br />drainage only, and are significantly oversized (all culverts are 30 -inch diameter CMP). Sediment traps will be <br />constructed in select locations to intercept and retain excess sediment from the road. The proposed pad location is <br />on the side of a small knoll, so upgradient drainage will be limited. The limited amount of drainage from <br />upgradient areas will be intercepted and routed around the borehole pad by a small designed upgradient diversion <br />ditch along the west and north sides of the pad. Drainage from the small borehole pad will be controlled under a <br />Small -Area Exemption by gravel surfacing on the pad surface, temporary revegetation seeding of pad cut/fill <br />slopes, and by small interceptor ditch along the south and east sides of the pad, (size the same as the diversion <br />ditch, although the drainage area is significantly smaller) draining through a rock sediment basin to the adjacent <br />natural drainage <br />Road construction will involve soil recovery, placement of culverts, scarification and recompaction of surface <br />materials, necessary cut/fill work to establish the road profile, and placement and compaction of approximately 3 - <br />inches of suitable roadbase materials and 8 inches of pit -run gravel. It is anticipated that two to three turn -outs (up to <br />30 -foot wide) will be constructed in flat straight areas along the road to allow passing of heavy trucks. The 24 -foot <br />road surface will be graded and crowned, or sloped into the hillside, to promote effective drainage. <br />Construction of the borehole pad will involve soil recovery, installation of drainage structures, cut/fill pad <br />construction, and placement of gravel surfacing material to control dust and sediment from the pad area. Borehole <br />completion will involve drilling, installing, and grouting a 20 -inch diameter steel surface casing in place to a depth of <br />up to 80 feet (dependent on the ground conditions encountered). The borehole will then be advanced, using <br />directional drilling, to a depth of approximately 1,700 feet to intercept the mine workings. Water, drilling fluids, and <br />cuttings will be contained within one or more portable steel tanks (porta-pits) on the borehole pad. The borehole will <br />be drilled to a nominal diameter of 17 inches, and three welded steel carrier pipes, one 6.625, and two 2.375 inches in <br />diameter, will be suspended in the borehole and grouted in. A collar for pumping concrete or portable fabricated steel <br />chute will be fitted to the larger carrier pipe for concrete and material drops. Concrete or other materials will be <br />transferred underground using a pipeline or underground equipment to the location(s) where they will be used. <br />The 16LT Utility Borehole installation will remain in-place until it is no longer needed to support ongoing or <br />anticipated future mining operations. Reclamation of this installation will involve plugging and sealing the borehole, <br />regrading the pad and road areas to their approximate original configuration, soil material replacement, and reseeding <br />with TC's standard Pastureland Seed Mixture, or an alternate seed mix, if requested by the surface landowner. <br />MR14-283 2.05-45.25 10/30/14 <br />