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iii iiniiiiiiiu iii <br />Mountain Coal Company <br />West Elk Mine <br />Annual Subsidence Report <br />Year -End Report <br />The most current subsidence survey for the West Elk Mme was performed in October and <br />November 1995, by Valley Survey Inc. The survey was wnducted using radial and level <br />loop survey methods. The instnunent used was an HP 3820A Total Station. <br />The following tables reflect the northings, eastings, average pre-mining elevations, the <br />previous report elevations (August 1995), the current survey elevations, subsidence from <br />August 1995 to November 1995 and total subsidence. <br />The following tables indicate that the maximum total subsidence to date is 8.21 feet and <br />occurs over both the F and B Seams at point No. 41, which is over the center of the 1st <br />Northwest Longwell Panel. The subsidence measured is well within the range of the <br />predicted subsidence, (Exhibit 60, Volume 13). In this area of two-seam mining, complete <br />maximum subsidence can be calculated by simple addition of the maximum predicted <br />subsidence for both the F and B Seams. The total predicted subsidence for the 2-seam <br />mining is 10.22 feet. <br />The visual effects of subsidence for this survey period were not detected by field <br />personnel. The cracks seen last year over the B-Seam panels, are healing well and many <br />are not perceptible. This is due in part to strain relief over the other longwall panels. <br />Mining advance was limited to the B Seam development in the B-West Mains, Jumbo <br />Mains, Eighth Northwest Tailgate and Headgate, and the North Northwest Headgate from <br />July 1995 to October/November 1995. The longwall retreated in the B6, and B7 <br />Northwest Longwell Panels (NWLW) since the July/August 1995 Mid-Year Report. The <br />longwall is currently (May 1996) operating in the B8 Panel. <br />