REP14956 - Laserfiche WebLink

Home Browse Search

iii iiiiiiiiiiiu iii 999 ~~~~'E OF ~OLOI~ADO DIVISION OF MINERALS At~14 GEOLOGY ^~-, Deparlmem of Nawral Resources 1313 Sherman St., Room 215 Denver, Colorado 80203 D I v 15 1 0 N O F Phone: (303) 866-3567 MINERAL S FAX. (303)ft32-8106 r& GEOLOGY RECLAMATION MI NING•SAFETY Bill Owens Governor Greg E. Walther Mazch 26, 1999 Executive Director Michael B. long Dinsion Director John Walters Powderhorn Coal Company P.O. Box 1430 Palisade, CO 81526 RE: Roadside Portals Mine (Permit No. C-81-041) 1998 Annual Subsidence Report Deaz Mr. Walters: The Division has reviewed the 1998 Annual Subsidence Report. As the report candidly acknowledges, only one of the two required ground inspections above the North Portal workings was conducted during 1998, as a result of staffing turnover in the engineering department. Fortunately, little secondary recovery was conducted during the year, so it is likely that minimal subsidence would have manifested at the surface over the workings. Subsidence phenomena observed during the inspections conformed with subsidence predictions in the approved permit. There appears to have been no loss of data or damage to the environment as a result of the single missed inspection. It is important, however, that the two required annual inspections be conducted in the future, particularly as the mains are extended beneath the north flank of Jerry Creek. During previous inspections, several subsidence-related cracks were observed, and during 1996 and 1997 inspections, these cracks were observed to be filling in with sediment and detritis, or "healing". During the ] 998 inspection, these sites were apparently not observed. During 1999 inspections, these cracks should be reinspected if their locations can be established, and their condition should be documented photographically. In addition, future reports should identify the individuals involved in conducting the inspection and preparing the report. In conclusion, although certain modifications are warranted for future reports, the Division has determined that the 1998 report provides an adequate record of subsidence observations conducted at the Roadside complex during the year, and the report is accepted as submitted.