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MOUNTAIN COAL COMPANY <br />West Elk Mine <br />1997 Aunual Subsidence Report <br />Year-end Report <br />The most current subsidence survey for the West Elk Mine was performed in October of 1997, <br />by Valley Survey Inc. The survey was conducted using radial and level loop survey methods. <br />The instrument used was a HP3820A Total Station. <br />The following tables reflect the northings, eastings, average pre-mining elevations, the previous <br />report elevations (July 1997), the currently survey elevations, subsidence since the July 1997 <br />report, and total subsidence. <br />The tables indicate that the maximum measured subsidence to date is 8.25 feet and occurs over <br />both the F and B Seams at point No. 41, which is over the center of the Ist Northwest Longwall <br />Panel. The subsidence measured is well within the range of predicted subsidence, (Exhibit 60). <br />In this azea of two-seam mining, complete maximum subsidence can be calculated by simple <br />addition of the maximum predicted subsidence for both the F and B Seams. The total predicted <br />subsidence for the 2-seam mining is 10.22 feet. <br />The visual effects of subsidence for this survey period are reported and mapped in the attached <br />Results of Field Investigations on the North Face of Jumbo Mountain, August 6, 1997, authored <br />by C. Richard Dunrud, P.E. Also included aze Intraseazch Aerial Photographs (Stereo Pairs) of <br />October 9, 1997, of the Jumbo Mountain Area (Photo No. 3741-53 through 3741-72). <br />Mining advance was limited to the B-Seam development in the 9th Tailgate, 10th Headgate, 11th <br />and 12th Headgate Sections and the mine headed east with entries in the Box Canyon Mains. <br />The longwall retreated in the 8th Northwest Longwall Panel (NWLVI~, 9th Longwall Panel, and <br />10th Longwall Panel since July 1997. The longwall is currently (May 1998) mining the 11th <br />Panel. <br />