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STATE OF COLORADO <br />DIVISION OF MINERALS AND GEOLOGY <br />Department of Natural Resources <br />1313 Sherman 8t., Room 215 ~ry~~ <br />Denver, Colorado 80203 II <br />Phone: 1303) 866-3567 <br />FAX:13031832-8106 <br />DEPARTMENT OF <br />NATURAL <br />DATE: October 19, 1995 _ RESOURCES <br />TO: Christine Johnston ~~ CoO Boomer <br />' ~ lames S Lochhead <br />FROM: Jim Pendleton Executive Director <br />~ C . <br />Michael B Long, <br />Dnis ion Dvecmr <br />RE: Aug. '95 Subsiden Monitoring Report <br />West Elk C al a (Permit #C-80-007) <br />I have reviewed the semi-annual subsidence monitoring data report <br />for the West Elk mine, which you forwarded to my attention. This <br />data report presents a summary of the survey data accumulated <br />through the August, 1995 survey. <br />The report presents a clear rendition of the voluminous subsidence <br />monitoring data for the West Elk mine. The presentation is <br />straightforward and comprehensive. <br />As of August, 1995 the maximum observed subsidence (at point No.61) <br />decreased 0.2 foot to 8.35 feet since its previous maximum of 8.55 <br />feet in October of 1994. Apparently some form of cantilevering may <br />have caused slight dilation, which is not uncommon in the North <br />Fork area. This vertical displacement was observed in a location <br />overlying multiple seam mining within both the F and B Seams. This <br />observed subsidence compares conservatively with the maximum <br />projected multiple seam subsidence of 10.22 feet. <br />After their October, 1994 survey I expressed concern because MCC <br />required five months to prepare and submit their data summary <br />report. This report was submitted within six weeks of the actual <br />survey event, which allows us more prompt review. <br />I recommend that you accept Mountain Coal Company's semi-annual <br />subsidence monitoring data report for August 1995, as submitted. <br />cc: David Berry <br />Doc: M:\MIN\JAP\MTGSUB95.REP <br />JP/jP <br />