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MOUNTAIN COAL <br />COMPANYL.L.t;. <br />A Subsidiary of Arch Western Resources, LLC <br />August 11, 1998 <br />Mr. Jim Burnell <br />Colorado Division of Minerals and Geology <br />1313 Sherman Street, Room 215 <br />Denver, CO 80203 <br />RECEIVED <br />AUG 1 4 1996 <br />DIV. OF MINERALS <br />8 GEOLOGY <br />West Elk Mine <br />P O Boz 591 <br />5174 Highway 133 <br />Somerset, CO 81474 <br />(970)929-5015 <br />Faz (970)929-5595 <br />RE: 1998 Mid-Year Subsidence Report; West Elk Mine; Permit No. C-80-007 <br />Dear Jim: <br />Mountain Coal Company, LLC (MCC) completed the mid-year subsidence survey during August <br />1998. The information here-in provided is in the format approved by the Division as a result of <br />Minor Revision No. 96. Please find attached, two tables of the subsidence survey data for the <br />subsidence grid shown on Map 29 in MCC's permit. <br />The survey was conducted by Registered Land Surveyors of E. Schaaf and Associates, Inc., using <br />a Trimble 4000 Series Global Positioning System (GPS). Conventional survey equipment was <br />also utilized. <br />The results of the survey (see attached tables) show that very little movement has occurred since <br />the previous survey in October 1997. Maximum total subsidence continues to be within the range <br />of predicted subsidence (2.25 feet for F Seam, 7.97 feet for B Seam and 10.22 feet total) for F <br />and B Seam mining (Exhibit 60, Volume 13). <br />As reported previously and discussed with the Division, MCC intends to provide a revision <br />application to eliminate the grid shown on Map 29, as it is no longer providing useful data. MCC <br />has been surveying the Jumbo Mountain area and the two Northeast Panels using aerial <br />photogrammetric methods, as approved per PR #5. The aerial photo data collected for the Jumbo <br />Mountain mining area will be presented in the revision application as verification of the accuracy <br />of the photogrammetric methods. MCC plans to provide this revision application during <br />September 1998. <br />During the period October 1997 to August 1998, MCC completed longwall mining of the 1 ONE <br />and 11NE longwall panels (formerly known as the 1NE and 2NE panels). The longwall was <br />