2009-09-21_PERMIT FILE - C1980007A (21)

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West Elk Mine Soil Stockpiles As West Elk Mine is an underground mine and most of the reclamation will not begin until the end of the life of the mine, it is necessary to have subsoil and topsoil stockpiles. The main topsoil pile is located to the south of the run -of -mine coal stack -pad and will be used for reclamation of the main mine facilities area. Some subsoil from the subsoil pile in Sylvester Gulch, (Live Subsoil Pile #I) as well as the topsoil from the stockpile at the North Soil Storage Area (NSSA), will be used for reclamation of the Lower Refuse Pile. MCC has also stockpiled topsoil from the Refuse Pile Expansion (RPE) area and the widening of the mine entrance at the NSSA on the north side of Highway 133. Landslide Corrective Measures In 1997 and 1998, MCC employed several corrective measures to stabilize the landslide at the main mine facilities area, as surges of movement had been experienced in 1996 and 1997. The corrective measures included the installation of rock buttresses, stone columns, horizontal drains, pins (micro - piles), and the expansion of the roller compacted (RCC) buttress. These structures are described in detail, and their effectiveness in improving the stability of the facilities area is discussed in Exhibit 14C, 1998 Landslide Corrective Measures Report by Ban Engineering /Harding Lawson Associates. The purpose of the corrective measures was to prevent catastrophic failure, which MCC was successful in doing. MCC will continue to evaluate the effectiveness of the corrective measures over time to evaluate their effectiveness for the long term (i.e. post - reclamation). MCC is collecting water level data and movement data from 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 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 measures in 1998. A revision including the updated information will be provided to the CDMG by July 30' of each year. In the spring of 1999, MCC drilled two horizontal holes from the surface, at the abandoned main mine site substation, to intercept small sumps in the F -Seam to drain the water that accumulates in these sumps. The water that accumulates in these sumps is primarily surface water and near surface groundwater that infiltrates through the colluvium above the F -Seam and into the F -Seam workings. Once the water is in the sump, it then infiltrates through the F -Seam floor and into the unstable surface soils within the main mine site landslide. It is important that water sources to the surface soils be controlled in order to improve the local and global stability. These two holes are a test to determine if this method of draining the sumps is feasible. These sumps are located near the main F -Seam portals. They are not part of MCC's mine water handling system. These sumps have not been nor will be used to handle a large inflow event. The sumps are too small and if they overflow, they will flow into the belt and travel ways. Drain A will be drilled approximately 1,100 feet and into the floor of one of the main collection sumps. Drain B will be drilled approximately 1,400 feet, and into the bedrock fracture zone below the F -Seam sumps. If the holes are successful, MCC estimates that approximately 22 gpm will flow from the two holes and into pond MB -1. If the holes are successful, MCC will permit and construct additional drains that will remain upon final reclamation. In addition, MCC will update Exhibit 14c to include these drains and evaluate them for the final reclamation plan. 2.05 -28 Rev. 06105, 01106. 03106. 04106 & 05106- PRIO; 01109- MR350: 04109- TRIM 04109- MR353; 05109- MR354; 08109- TR118; 08109 - TRI19