2024-05-03_PERMIT FILE - C1980007 (2)

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2.05-61 Rev. 11/96- PR07; 10/20 TR148 measures installed in 1997 and 1998. However, due to the limited time that the structures have been in place, MCC has not had sufficient time to evaluate the effectiveness of these structures for the long term (i.e. post-reclamation). MCC is continuing to collect water level data and movement data from the various piezometers, inclinometers, and survey mirrors around the mine site on a scheduled interval. Based on the data collected, MCC will reevaluate the slope stability analyses after the spring runoff each year and where appropriate, update Exhibit 14C. The update will include an evaluation of the relative change in the factor of safety during the previous year and since the installation of the corrective measure in 1998. A revision including the updated information will be provided to the Division by July 30th of each year. In addition, after at least five years of data collection, MCC will reevaluate the reclamation plan in 2003, and modify as necessary to ensure that the mine will continue to be stable upon final reclamation. Seedbed quality material is removed from the temporary stockpile and distributed uniformly over the areas to be revegetated. Areas within the mine site are revegetated after construction using the permanent seed mix listed in Table 37 except for selected Areas which are landscaped to provide a pleasant working environment. Lower soil horizons are used for fill as subsoil base in order to obtain an overall soil depth necessary to enhance and sustain plant growth. Following topsoiling, and prior to planting, nutrients and soil amendments are added if needed to establish vegetative growth. Reseeded areas are mulched or the seed raked in to the soil. The West Elk Mine site will be returned to approximate original contour (AOC) as shown on Maps 58 and 59. However, not all material excavated from specific areas is required to be returned to achieve AOC. One of these areas is the expanded materials storage bench (MSB) which occurred in 1997. Approximately 16,000 cy of material was excavated to the west of the existing cutslope of the MSB to reduce the slope from 1.5:1 to 2.25:1, improving slope stability in this area of the MSB. Approximately 4,000 cy of topsoil was stockpiled in Topsoil Stockpile #5. Approximately 2,000- 3,000 cy of subsoil was used to repair and regrade slopes in the portal bench storage area and below the mine supply storage light-use road. The remaining 10,000 cy was placed on the east end of the MSB as an engineered fill to expand the surface area of the MSB. The subsoil used to repair and regrade nearby slopes will not be returned to the MSB during final reclamation, and as shown on Map 58B will not be needed to achieve AOC. The reclamation of all areas will be such that the areas will be stable, the hydrologic balance will not be impacted, topsoil will be salvaged, stored and replaced, and the disturbed areas will be revegetated. When the surface facilities are removed and the site regraded, the topsoil will be redistributed to a depth of 12 -18 inches over areas of the main mine facilities and 24 inches over areas in the Sylvester Gulch Facilities Area. These surfaces will be revegetated using permanent vegetation seed and the seedling mixtures. Fertilizer and mulch will be applied in accordance with the Topsoil Preparation Section. Roads When no longer needed for mining operations, the primary haul/access roads and other access and light-use roads not approved as permanent facilities will be removed and the areas reclaimed. The roads will be filled and graded to the approximate original contour (unless the roads were part of the original contour). Topsoil will be spread over these areas to a 12 to 18 inch depth for reclaimed roads on the main mine facility, and to a depth of 24 inches in the Sylvester Gulch Facilities Area.