2016-02-24_PERMIT FILE - C1982056 (2)

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Final reclamation of the dewatering wells and ventilation shaft will involve excavating down 4 feet from grade around the casing, cutting off the steel casing 3 feet below grade, hanging steel decking from the top of the Cut- off casing (this decking will be 30 feet below the top of the cut-off casing), placement of 30 feet of concrete in the casing (for a 3 -foot diameter cased hole, the 30 foot x 3 foot diameter cement plug would weigh approximately 32,000 pounds, which would be more than adequate to resist the calculated hydrostatic pressure and provide an effective seal). The remaining 3 feet will be filled with soil, and graded to blend with the surrounding terrain. . The access road will be graded to blend with the surrounding terrain, and the Culvert will be removed. The entire area will be topsoiled and seeded with the appropriate seed mixture. After the facilities are removed, the site will be regraded to blend with the existing terrain and the stockpiled topsoil redistributed over the area. The soil material stored adjacent to the site will be redistributed over the dewatering site and reclaimed road segments will be seeded with the pastureland seed mixture. Approved permanent access roads will remain intact for use by the surface owner. During the 10 -year liability period, TCC will maintain the road for monitoring purposes. After bond release, the land owner will assume responsibility for the road. The northern short section (2,500 feet) of the access road will be reclaimed unless otherwise approved by the CDRMS. The soil windrowed or stockpiled adjacent to the road will be seeded with the rangeland seed mixture. Rockdust Tank After removal of the rockdust tank and cement pad, the pit -run gravel of the truck access/unloading area will be dispersed across the .5 acres of disturbance. The area will be ripped before the stockpiled soil is reapplied and reseeded. 7 -North Escape Shaft When the facility is no longer required, the shaft will be plugged, and the site graded, re -soiled, and revegetated. Steps required to abandon the shaft will include removal of surface structures, demolition of the concrete foundation and piers, and sealing of shaft. After the surface structure is removed, the broken -up foLmdation and piers will be Put down the shaft, and decking will be suspended in the shaft 10 feet below -grade. The support beams and decking will be suspended from the steel casing by steel straps (i.e. I -beams or similar support structures) welded to the support beams. The steel straps will be welded to the existing 48 -inch diameter casing. Once this is completed, a 24 -inch thick reinforced concrete slab will be poured in-place over the previously placed decking. The void from the top of the concrete slab to within 5 feet of the surface will be backfilled with inert fill material (approximately 1.4 CY) from the surrounding area. The next 2 feet of the shaft will then be filled with concrete to form a surface plug for the shaft. Suitable fill material will be placed in the remaining 3 feet of the shaft (approximately 1.4 CY), and then the site will be re -soiled and revegetated. The redistributed soil will be seeded with the pastureland seed mixture. NMD Povver Borehole Upon completion of mining, and when the power borehole is no longer needed, the facilities will be removed and the site reclaimed. Removal of the surface facilities will involve dismantling of surface structures, which includes the powerline, transformer and pad, road and culvert, and building. After the facilities are removed, the site will be regraded to blend with the existing terrain, the stockpiled soil will be redistributed over the area, and the power borehole pad and reclaimed road segments will be seeded with the pastureland seed mixture. The entire road will be chisel -plowed after removing the geotextile. Drillhole or Well Plugging and Sealing, and Well and Pipeline Reclamation and Abandonment All drillholes will be plugged, sealed, and abandoned unless they are converted for long-term use as a monitoring or water -supply well. Deeper drillholes will be plugged with a minimum of 6 cubic yards (about 750 feet) of cement slurry — this is the off-road transport capacity of a cement truck. Shallower drillholes will be plugged with between 3 and 5 cubic yards of cement slurry (as appropriate). The cement slurry will be tremied into the drillhole from the bottom of the hole, up through the target units. This will effectively plug and MR 15-294 2.05-106.2 02/02/16