Laserfiche WebLink
;: <br />iii iiiiiiiiiiiu iii <br />STATE OF COLORADO <br />DIVISION OF MINERALS AND GEOLOGY <br />Dep. nmcnl of Natural Rc~.ources _ <br />131 3 Sherman 51., Ruom L I S <br />Denver. Colorado NO?OJ <br />Phone 17071866-1Sh7 <br />FAY: I70A NR~N 106 <br />March 4, 1996 <br />Mr. Jim Kiger <br />Colowyo Coal Co. L.P. <br />5731 State Highway 13 <br />Meeker, CO 81641 <br />RE: Colowyo Coal Mine (C-81-019) <br />TR-36; Auger Mining Area #2 <br />Dear Mr. Kiger, <br />I~~~~ <br />DEPARTMENT OF <br />NATURAL <br />RESOURCES <br />Roy Romer <br />Guvernor <br />lames 5. Luchhcad <br />Executive Direclo~ <br />M¢hael B Lnng <br />Drvisinn Dneclo~ <br />The Division of Minerals and Geology received your technical revision application (TR-36) <br />to add Auger Area #2 to the Colowyo mine plan. The proposed auger mining will occur <br />within the X Seam along the north and east end walls of the West Pit. In the future, auger <br />mining may be conducted in either the C Seam or D Seam. This would be the subject of <br />a future revision application. Jim Pendleton of our office reviewed the revision and has the <br />following comments that need to be addressed prior to approval of the revision; <br />Streeter Pit and Stability Evaluation, North Wall of West Pit..." <br />In conjunction with the technical revision application, the Division reviewed the <br />"Geotechnical Investigation of the West Pit Excess Spoil Disposal Site..:', and the <br />CONFIDENTIAL CTL/Thompson report entitled, "Auger Mining Analysis, West Pit and <br />Subsidence Concern <br />The plan appears straight forward. No structures appear to be at risk, if unexpected <br />subsidence were to occur, other than the West Pit Disposal Pile. If subsidence were to <br />occur through the approximately 250 feet of backfill and bedrock, the Division suspects that <br />minor cracking and deflation would be the only surface expression. These impacts could be <br />mitigated by regrading and repair. CTL/Thompson projects that the magnitude of any <br />subsidence should be small in relation to normal consolidation of the fill thickness. Because <br />the augered area will underlie the West Pit Fill it would be difficult to distinguish between <br />subsidence due to collapse and subsidence due to normal consolidation. <br />