2022-03-10_REVISION - C1981044 - Laserfiche WebLink

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Once an area of the pile reached the design elevation, a minimum of 2.0 feet, and up to 3.5 feet of suitable non-toxic material was placed as cover on that area. Because the No. 9 Mine portal excavation was filled with waste material,the excavated material in the berm around the pit(approximately 185,000 cubic yards)was used as the source for the non- toxic cover on the waste pile. Following cover material placement, soil or suitable grow media was placed and spread over the reclaimed area to a depth of 6 to 12 inches. Following completion of reclamation for the entire waste pile,any material remaining in the berms was distributed evenly over the No. 9 Mine yard area. After redistribution of soil and growth media, the soil materials were sampled and analyzed, and any necessary amendments were added to assure adequate soil fertility for revegetation. The area will be returned to a land use of rangeland/ wildlife habitat by seeding with a cover crop and then the rangeland/wildlife seed mixture at a rate of 17.25 pounds/acre if a rangeland drill is used. Reclamation of the Refuse Disposal Area was completed in 2021. Solid Waste Disposal Facility Any non-hazardous debris resulting from demolition of mine buildings and facilities, and/or other materials, as defined in Rule 4.11.4, Disposal of Non-Coal Waste, may be disposed of in a permitted Solid Waste Disposal Facility. The proposed solid waste disposal area covers approximately 4.5 acres in Section 32, adjacent to the existing coal refuse pile and No. 9 Portal Area, as shown on Map 25, Structures and Renewable Resources. The facility was constructed and reclaimed in accordance with applicable provisions of Rule 4.11.4, Disposal of Non-Coal Waste. The disposal area was excavated, as-needed, to provide for effective waste containment and to assure that sufficient material is available to cover the non-coal waste material with a minimum of two feet of soil material. The excavation maintained at least an eight foot barrier of soil material between the adjacent coal refuse waste pile and the non-coal disposal area, and excavation depth was limited so that the bottom of the excavation is well above the natural ground water table in the area. The reclamation of the waste disposal area was finished in 2009 The total area for this facility was approximately 4.5 acres, however, only a portion of the area was in active use at any given time. Waste materials were placed, spread, and compacted to assure long-term stability. If the waste disposal area was used for non-coal wastes that could be subject to wind-loss or vector infestations, or which may be flammable, sufficient cover material will be maintained in stockpile to both meet applicable final cover requirements, and provide for temporary cover requirements. Surface drainage is controlled by the ditch and pond system already in-place, as shown on Map 26, Drainage and Sediment Control Plan. The final cover placement consisted of a minimum of two feet of suitable, non-toxic cover material, including spoil or other cover material and topsoil or best available plant-growth media(in accordance with Rule 4.11.4). These areas were then be revegetated by seeding with a cover crop and then the pastureland seed mix as the approved postmining land-use as shown on the Reclamation Plan Map (Map 29). Postmining Discharge—No. 9 Mine The "P" seam was mined in the No. 9 Mine from March 1985 to August 1988. The mine was driven northward in a downdip direction. The approximate elevation of the bottom of the No. 9 mine portal entry was 6,305 ft., and present ground surface is approximately 6,350 ft. No significant full-extraction mining was performed in the mine. The water level in the Twentymile Sandstone is estimated to be approximately 6,260 ft.,at its highest level in the area MT8 2.05-30 Revised 02/28/22