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iii iiiiiiiiuiii iii <br />999 <br />STATE OF COLORADO <br />DIVISION OF MINERALS AND GEOLOGY <br />Depa rlment of Natural Resources <br />131 3 Sherman SL, Room 215 <br />Denver, CO 80203 <br />Phone: 13031 866-3567 <br />FAX: 13031 832-8106 <br />DATE: February 10, 1994 <br />~~ pF Cp~9 <br />.~ b <br />~~~ga <br />~ ~B T6 ~ <br />Roy Rnmcr <br />Governur <br />Michael B Lung <br />Division Duec mr <br />TO: Janet Binns ~ <br />~~~ <br />FROM: Jim Pendleton <br />RE: Colowyo ~e e, Technical Revision No. 26, <br />Reduction of Subsidence Monitoring of Streeter Fill <br />(Permit No: C-81-019) <br />Colowyo's TR-26 requests a reduction in subsidence (consolidation <br />/ settlement & slope stability) monitoring of the facial slope of <br />the Streeter Fill. The operator is currently required to monitor <br />one piezometer, conduct a spring & seep survey, and survey twelve <br />subsidence monuments quarterly. Colowyo proposes to continue <br />monitoring the piezometer and conducting the spring and seep survey <br />quarterly, but to perform the survey monitoring annually. <br />The operator correctly observes that the past twelve year's <br />monitoring has documented normal consolidation settlement of the <br />massive Streeter fill. Further, the piezometer has never detected <br />any abnormal occurrence of ground water within the fill. For this <br />reason I believe it appropriate to approve Colowyo's requested <br />technical revision with one condition, as follows. In the event <br />that an abnormal rise in the water level of the piezometer (greater <br />than 2 feet in any quarter) or the development of springs or seeps <br />occurs, the operator shall notify the Division within one day and <br />complete a survey of the twelve subsidence monuments and report the <br />results to the Division within one month. <br />cc: Larry Routten <br />Steve Renner <br />Doc: M:\COAL\JAP\STREETER.MON <br />JP/JP <br />