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Minor Revision No. 315 <br />Main Landslide and Material Storage Bench Geotechnical Investigation and Stabilization <br />Design <br />August 3, 2005 <br />Page 2 of 2 <br />The installation of a piezometer west of the main landslide will consist o£ <br />• Installing a standpipe piezometer adjacent to surface mirror 17 as shown on the attached <br />map titled, "Map 53 Surface Facilities, Main Mine Site, West Elk Mine;" <br />• Pumping groundwater from neazby stone column 61 (SC61) and monitoring the levels, <br />temperatures and conductivities of groundwater in surrounding piezometers; <br />• Using the information to obtain recommendations for appropriate groundwater mitigation <br />measures. <br />Locations of the pumping well and piezometer in relation to the mine's surface .features are <br />shown on the attached map entitled, "Map 53 Surface Facilities, Main Mine Site, West Elk <br />Mine." These installations will occur on previously disturbed lands within the permit azea <br />boundary and owned by Mountain Coal Company. The project installation is scheduled for <br />completion in August 2005. <br />Both these investigations will involve pumping groundwater. MCC will utilize a combination of <br />overland hoses and existing surface water drainage structures for carrying pumped water to either <br />Sylvester Gulch or to surface water storage and/or dischazge facilities. <br />Pumping the groundwater well at the MSB will be a short-term procedure to support the <br />investigation. If the investigation indicates longer-term pumping is needed to facilitiate <br />stabilization, MCC may obtain permission to use this well for that purpose with appropriate state <br />agencies. At the end of this well's useful life, it will be plugged and abandoned in accordance <br />with CDMG requirements. <br />The piezometer installed west of the main landslide will be a long-term installation, with <br />anticipated usefulness expected throughout the remaining life of the mine. At the end of this <br />piezometer's useful Life, it will be filled with grout. <br />Please provide any comments or requests for additional information to either Jim Schrack (970- <br />929-2232) or me (970-929-2238). <br />Sincerely, <br />Henry A. azbe <br />Environmental Engineer <br />cc: Pete Wyckoff <br />Phil Schmidt <br />Eazl Quesenberry <br />