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<br />u~ago Cyprua Yampa Vallsy Coal Corporation <br />sf~ An AffiY,ro wGYav+-rwr, Cortprry <br />• iii iiuiiiiiiiu iii <br />29687 ao,m camas no.e •zr <br />O„ rilMk, CO BM61 <br />Pho„s r303) 87g3B00 <br />March 22, 1990 <br />Randy Price <br />Reclamation Specialist <br />Colorado Mined Land Reclamation Division <br />1313 Sherman Street, Room 215 <br />Denver, CO 80203-2273 <br />~~~`'~Q~~~~ <br />a.AR ~ (. 190 <br />iIAINED LA~;C <br />RECL.4MAT!C!v rl/~"~ 'PJ <br />Dear Mr. Price: <br />Re: Subsidence Report - Foidel Creek Mine; Permit C-82-056 <br />Enclosed, please find two copies of the subsidence report for the second <br />half of 1984. As shown on the enclosed map, the longwall face advanced <br />approximately 1350 feet during the period of September, 1989 thru December <br />1989. This represents the initiation of longwall mining at the Foidel Creek <br />Mine. <br />the dai:a indicates that significant subsidence occurred at monuments A-2 <br />thru A-7, with the maximum amount of subsidence being recorded at monument <br />A-3. Subsidence ranged from 0.i' to 3.2' over the mined area. As is <br />evident from the data the maximum subsidence occurred down the center line <br />of i.he I.~anel, and minor amounts of subsidence occurred ever the Bead and <br />tail ,ate s. <br />In order to determine the subsidence monument elevation, the monumr~nt~ were <br />sui°veyed five times during the period of July 16, 1988 thru Octobr:r 1G, <br />19?9. These five points were then averaged to obtain the pre-mine average <br />elevation for the various monuments. It is TCC's opinion that this provides <br />a more accurate representation of the monuments pre-mining elevation, as <br />the averaging process will reduce the surveying error introduced by climatic <br />conditions. <br />It should he noted that the in-place monitoring net varies slightly from the <br />approved one. The differences lie in the fact that monument A-1 was not. <br />installed, however this is a panel centerline monument and does not impact <br />the quality of the information obtained from the monitoring program. <br />If there are questions or comments, please contact me at you convenience. <br />Sincerely, <br />~~~~ <br />Richard I~iils <br />Supervisor; Environmental Affairs <br />RAM:dg <br />Enclosures <br />crnRUs <br />