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_MOONTAIN COAL <br />-=may -'~CO~PANY~~C. <br />A Subsidiary of Arch Western Resowces, LLC <br />August 3, 2005 <br />Mr. Tom Kaldenbach <br />Colorado Division of Minerals and Geology <br />1313 Sherman Street, Room 215 <br />Denver, CO 80203 <br />RECEIVED <br />AUG 0 9 2005 <br />OMLOn o!&ty~„r.::3 ~Si+M deUOgY <br />West Elk Mine <br />POBox 591 <br />5174 Highway 133 <br />Somerset, CO 81434 <br />(9'70) 929-5015 <br />Fax (970) 929-5595 <br />RE: Mountain Coal Company L.L.C., West Elk Mine; Permit C-80-007; M nor Revision <br />Number 315 (MR-315); Main Landslide and Material Storage Bench (MSB) Geotechnical <br />Investigation and Stabilization Design. <br />Deaz Mr. Kaldenbach; <br />Mountain Coal Company, L,L.C. (MCC) submits the enclosed Application for D~Iinor Revision <br />No. 315 to perform a geotechnical investigation of the Main Landslide and Material Storage <br />Bench (MSB) at the West Elk Mine. The results of the proposed investigation vaill be used to <br />support the design of possible stabilization techniques. This Minor Revision is :Number 315 to <br />CDMG Permit Number C-80-007. Three copies of the Application Form, this explanatory letter <br />and the associated map are included. <br />Landslide stabilization studies and corrective actions have been performed over the life of the <br />mine. The studies proposed here augment the existing stabilization work currently being <br />conducted at the West Elk Mine. <br />Recent investigations have indicated that movement has taken place near the west side of the <br />Main Landslide Area and at the MSB. The subject of this Minor Revision (MR-315) is an <br />investigation focused on obtaining data for design of corrective measures. Although not the <br />subject of this Minor Revision, the anticipated corrective measures aze additionldl horizontal <br />drains on the west and east sides of the Main Landslide and along-term pumping well on the <br />MSB. <br />The investigation activities associated with this proposed Minor Revision encompass two major <br />components: 1) investigating groundwater at the Material Storage Bench (MSB), and 2) <br />installing a piezometer on the west side of the Main Landslide. <br />The groundwater investigation at the MSB will consist of: <br />• Installing a pumping well on the northern edge of the MSB as shown on the attached map <br />titled, "Map 53 Surface Facilities, Main Mine Site, West Elk Mine;" <br />• Pumping the well for testing purposes and monitoring the levels, temperatures and <br />conductivities of the groundwater in surrounding piezometers; <br />• Using the information to obtain recommendations for appropriate groundwater mitigation <br />measures. <br />