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Mountain Coal Company <br />West Elk Mine <br />Annual Subsidence Monitoring Report <br />Year-end Report 1994 <br />The most current subsidence survey for the West Elk Mine was performed in October <br />1994, by Messenger and Associates. The survey was conducted using radial and level loop <br />survey methods. The instruments used were a Wild, T-1, theodolite; aNikon-ND 20 <br />distance meter; and an unspecified level. <br />The following tables reflect the northings, eastings, average pre-mining elevations, the <br />previous report elevations (June, July, August 1994), the current survey elevations, <br />subsidence since the Mid-year Semi-Annual Monitoring 1994 Report and total subsidence. <br />These tables indicate that the maximum total subsidence to date is 8.55 feet and occurs <br />over both the F- and B-Seams at point No. 61, which is over the center of the 1st <br />Northwest Longwall Panel. The subsidence measured is well within the range of the <br />predicted subsidence (Exhibit 60). In this area oftwo-seam mining, complete maximum <br />subsidence can be calculated by simple addition of the maximum predicted subsidence for <br />both the F and B Seams. The total predicted subsidence for the 2-seam mining is 10.22 <br />feet. <br />There were no additional visual effects of subsidence reported during this period of <br />monitoring. There was, however, a recent follow-up investigation and discussion <br />submitted to the Division regarding the cracks that were observed and reported in the <br />1994 Mid-year Report (Semi-Annual Subsidence Monitoring Report 1994). <br />Monitoring of a wood-framed structure constructed in 1994 over the pillars between the <br />BS and B6 Northwest Longwall panels (NWLW), after mining the BS NWLW panel <br />resulted in an overall lowering of the site by an average of 1.52 feet and an average <br />easterly horizontal shift of 1.71 feet. No damage to the building has occurred. A photo <br />panel control point located nearby over the approximate middle of the BS panel lowered <br />approximately 4.17 feet. <br />Mining advance was limited to the B-Seam development in the B-West Mains, Jumbo <br />Mains, and the Sixth, and Seventh Northwest Headgates, from July 1994 to October <br />1994. The longwall retreated in the B4 and BS Northwest Longwall Panels (NWLW) <br />since July 1994. The longwall is currently (April 1995) retreat mining in the B6 NWLW <br />Panel. <br />sub 1994. doc. <br />