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STATE OF COLORADO <br />DIVISION OF RECLAMATION, MINING AND SAFETY <br />Department of Natural Resources <br />1313 Sherman St., Room 215 <br />Denver, Colorado 80203 <br />Phone: (303) 866-3567 <br />FAX: (303) 832-8106 <br />INTEROFFICE MEMORANDUM <br />Date: 18 June 2009 <br />To: Joe J. Dudash <br />From: Marcia L. Talvitie, P.E. %W-1;1 <br />Subject: Bowie No. 2 Mine (Permit No. C-1996-083) <br />TR-61 - Coal Refuse Pile Slope Inclination <br />Adequacy Comments - No. 2 (Geotechnical) <br />COLORADO <br />D I V I S I O N OF <br />RECLAMATION <br />MINING <br />SAFETY <br />Bill Ritter, Jr. <br />Governor <br />Harris D. Sherman <br />Executive Director <br />Ronald W. Cattany <br />Division Director <br />Natural Resource Trustee <br />As you requested, I have reviewed Bowie Resources' 11 June 2009 response to the TR- <br />61 adequacy issues I raised in my 29 May 2009 memo to you. Each of the items I <br />addressed has been successfully resolved by the response package, and no further action <br />is necessary with respect to the Geotechnical aspects of TR-61. These specific items <br />(along with my originating comments) are enumerated below. <br />Vibrating Wire Piezometers <br />Page 14 of the Volume IX text in the application states, in essence, that quarterly <br />inspection reports will provide a summary of instrumentation monitoring on <br />CMWDA2, including a discussion of the vibrating wire piezometer data. This data <br />will determine if the measured pore pressures are relatively stable, and consistent <br />with those incorporated into the TR-56 BGI report. The Operator commits to having <br />a geotechnical engineering firm continue instrumentation monitoring on a quarterly <br />basis. Installation of any additional vibrating wire piezometers is proposed to be at <br />the discretion of the geotechnical engineering firm. <br />While specific details ofpiezometer location and/or modification have not been <br />provided, the Operator has committed to the utilization of a geotechnical firm for <br />monitoring of the piezometers and for determining the necessity of additional <br />piezometers. In accordance with the recommendations of the BGI TR-56 report, <br />please revise the monitoring frequency to be a minimum of once per quarter. <br />Page 14 has been updated accordingly - no further action is required: <br />Office of Office of <br />Mined Land Reclamation Denver • Grand Junction • Durango Active and Inactive Mines