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TEL N o . 0 . 0 0:01 II I I II I II I II IIII II~~_~ <br />sss <br />STATE OF COLORADO <br />UI VISION OF MINCRALS ANU GEC)LOC;V ..~ <br />[Inp.,Nq,CN OI N~IUgJ Rrv`ourCr. <br />u, v l\ 1 • 6 r <br />1311 Sbcrm.ln SL, Rt¢nn 115 M I N E IiA i 5 <br />Prmrr, Colpr.ulir BO'ot .._b, <br />Phunr: 1303/ na[. 35EO C f n I. 6 t: Y <br />rA>,: c+u31s3~-nloc ••~,-~•*~oN <br />. MIN i,a4•laFl l <br /> <br />DATE: <br />March 12, 1999 lull (rwxus <br />c,,.,•rn.•r <br /> Gn.~l; C N•alrh,~r <br /> <br />TO: <br />Dan Mathews <br />~~ ~ <br /> <br />11 1 ,., wvc I Porr,nr <br /> <br />Mlrl'i.\r10 I~.nC <br /> ~~ <br />FROM: Jim Pendleton • <br />~- <br />RE: Powderhorp "Eoal..~mpany 1998 Annual Subsidence Report <br /> "~eCmlt No: C-Bi-041) <br />I have reviewed the 19913 annual subsidence report submitted by Powderhorn Coal <br />Company for its Roadside/Cameo mining complex. The approved permit requires the <br />conduct of twice yearly visual inspections of the potentially effected area above both the <br />Roadside South and Roadside North mines. The unidentified author of this report candidly <br />observes that, because of staffing turnover in the engineering department, only one <br />inspection was conducted above the North Portal workings during December of 1998. Thin <br />and sparse snow Cover appear to have allowed this inspection to be definitive. No <br />subsidence impacts were discerned by the Inspection. Fortunately, little secondary recovery <br />(pillaring) was conducted during 1998, so I would anticipate minimal subsidence to be <br />manifested at the ground surtace above the North Portal workings. Two Inspections were <br />conducted above the South Portal workings. No mining has been conducted within the <br />South Portal workings since 1996, although these workings are being ventilated and <br />maintained for possible future extraction. No phenomena were observed during these <br />inspections which did not comply with projections Included within the permit subsidence <br />predictions. <br />The regulatory decision concerning possible enforcement action is yours. In my opinion <br />there appears to have been no loss of data or damage to the environment as a result of the <br />missed inspection. It is important, however, that the operator conduct the two required <br />Inspections, particularly as the mains are extended beneath the north flank of Jerry Creek. <br />During previous Inspections, conducted and documented by Mr. tarry M. Reschke, f .E. <br />(previously in the employ of Powderhom Coat Co.), several subsidence-related cracks were <br />observed. During the 1996 and 1997 inspections, these cracks were observed to be filling in <br />with sediment and detritis, or 'healing'. During the 1998 inspection no observations of these <br />previous sites were conducted. It would be informative for these cracks to be reinspected <br />during future inspections if there location can be established from Mr. ResChke's previous <br />inspection reports and included photographic record. I recommend that the company be <br />directed to <br />