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~. ~. <br />iiiiiiiuiiiiiiiiii- <br />STATE OF COLORADO <br />DIVISION OF MINERALS AND GEOLOGY <br />Depar(mem of Nani ral Resources <br />1313 Sherman SL, Room 215 <br />DIVISION OF <br />Denver, Colorado 80203 M~ N E R A L S <br />Phone 13U31 866-3567 <br />FAX: (303) 832-8106 & <br />GEOLOGY <br />RECLAMATION <br />MINING•SAF ETY <br />DATE: June 14, 2000 <br />dill Owens <br />Governor <br />~_`' <br />T0: Dan Mathews Greg E. Walther <br />Eeecmive Dueuor <br />- M¢hael B. Long <br />FROM: Jim Pendleton _ °rvision°ie°°` <br />RE: Powderhorn- / ompany 1999 Annual Subsidence Report <br />(Permit No: C-81-041 ) <br />I have reviewed the 1999 annual subsidence report submitted by Powderhorn Coal <br />Company for its Roadside/Cameo mining complex. The approved permit requires <br />the conduct of twice yearly visual inspections of the potentially effected area <br />above both the Roadside South and Roadside North mines. The report, which bears <br />no author name, was forwarded by J. E. Stover & Associates, consultant to <br />Powderhorn Coal Company. The two required visual inspections were completed on <br />July 23, 1999 and December 15, 1999. Thin and sparse snow cover appear to have <br />allowed both of these inspections to be definitive. Minimal to insignificant <br />subsidence impacts were discerned by the inspections. <br />No Coal Recovery has been conducted in the Roadway South entries since 1996. <br />The Roadside North Portals produced a total of 350,810 tons of raw coal during <br />1999. Because little secondary recovery (pillaring) was conducted during 1999, <br />only extremely minimal subsidence appears to have be manifested at the ground <br />surface above the North Portal workings. No phenomena were observed during <br />these inspections which did not comply with projections included within the permit <br />subsidence predictions. The mine portals have been closed and no additional mining <br />is projected to occur at the Roadside Mines in 2000. <br />The visual inspection for subsidence concentrated upon areas undermined within <br />the past two years. In the case of the idled Powderhorn Mines this limited the <br />intense inspection to the 2nd West Section of the Powderhorn North Mine. <br />Portions of the badlands topography overlying the 2nd West Section are <br />characterized by dramatic terrain relief. These areas were carefully scrutinized, <br />giving particular attention to areas where slumps or cracks might be more <br />