2014-11-17_PERMIT FILE - C1982056A (5)

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5 -Main North Cement Borehole (MR14 -283 In order to provide concrete for the planned Wolf Creek ramp development and construction activities, TC plans to complete a cement borehole, to be located over our 5 -North Mains, extending into the existing Wadge Seam Mains. The borehole will extend to a depth of approximately 1,500 feet, will be drilled to a 12.25 -inch diameter, and cased to a 9.875 -inch diameter. Subsequent to this initial use, it is anticipated that the borehole could be retained and utilized for other purposes to support the future mining and related operations in the Wolf Creek Seam. The proposed borehole will be accessed from the paved County Road (RCR33), using the existing established access for the 6 -Main North Shaft Facility, with a new light -use road to the borehole pad location, as shown on Map 24 (4/4) and Figure 49CC -F1. The proposed cement borehole will require construction of approximately 0.6 mile of new light -use road from the existing established 6 -Main North access road. A new borehole pad (approximately 200 x 200 ft.) will be constructed to support both the initial drilling and borehole completion activities, and subsequent cement delivery and related operations. The 5 -Main North (5MN) Cement Borehole installation will consist of the new light -use road and borehole pad; adjacent soil material stockpiles, and the lined and grouted borehole extending into the 5 -North Mains in the Wadge Coal Seam. The road disturbance corridor will be 40 feet wide, although the actual road surface will only be approximately 24 feet wide. The total road disturbance will be approximately 3.1 acres, and the maximum pad disturbance will be approximately 0.9 acre. Site - specific investigations required for design and permitting of the cement corehole include a cultural resource survey and wildlife consultation. The cultural resource survey results are summarized by the survey report provided in Exhibit 6T, and a wildlife consultation letter is included in Exhibit 23C. The perimeter of all areas to be disturbed will be clearly marked and construction drainage control measures (silt fences or wattles) will be in place prior to disturbance. In order to reestablish effective vegetative cover during site reclamation, TC will recover and stockpile a maximum of 1.0 foot of soil material from the road and pad disturbance areas. A maximum of approximately 5,060 cy of soil will be recovered and stockpiled from the road disturbance area, and approximately 1,480 cy from the pad area. Natural vegetative materials incorporated into the salvaged soil materials and seeding with the soil stockpile stabilization seed mixture will assist in stabilizing the stockpiled soil material and preventing erosion or loss of the soil materials. The proposed pad and road location are on a minor ridgeline, so upgradient drainage will be limited. The limited amount of drainage from upgradient areas will be intercepted and routed around the borehole pad by a small upgradient diversion ditch on the north side of the pad and the road will not cross any natural drainages, so no culvert installations will be needed. Drainage from the small borehole pad area will be controlled under a Small -Area Exemption by gravel surfacing on the pad surface, the upgradient diversion ditch which will drain through a rock sediment basin to the adjacent natural drainage, and temporary revegetation seeding of pad cut/fill areas. Road construction will involve soil recovery, scarification and recompaction of surface materials, any necessary cut/fill work to establish the road profile, and placement and compaction of approximately 3 inches of suitable road - base materials and 8 inches of pit -run gravel. Given the location of the borehole pad on top of the ridge and the relatively short access road, it is not anticipated that any truck turn-outs will be needed. The 24 -foot road surface will be graded and crowned to promote effective drainage. Construction of the borehole pad will involve soil recovery, installation of the upgradient diversion, cut/fill pad construction, and placement of gravel surfacing material to control dust and sediment from the pad area. Borehole completion will involve drilling, installing, and grouting a 14 -inch diameter steel surface casing in place to a depth of approximately 40 feet (dependent on the ground conditions encountered). The borehole will then be advanced, using directional drilling, to a depth of approximately 1,500 feet to intercept the mine workings. Water, drilling fluids, and cuttings will be contained within one or more excavated pits or portable steel tanks (porta -pits) on the borehole pad. The borehole will be drilled at 12.25 inches, and cased and grouted to a nominal diameter of 9.875 inches. A collar for pumping the concrete will be fitted to the cased wellhead. Concrete will be delivered by mix trucks, dropped down the borehole, and transferred underground to the ramp construction area using a pipeline or underground equipment. The 5MN Cement Borehole installation will remain in -place until it is no longer needed to support ongoing or anticipated future mining operations. Reclamation of this installation will involve plugging and sealing the borehole, regrading the pad and road to their approximate original configuration, soil material replacement, and reseeding with TC's standard Rangeland Seed Mix. MR14 -283 2.05-45.26 10/30/14