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COLORADO <br />r - Division of Reclamation,. <br />Mining and Safety <br />Department of Natural Resources <br />1313 Sherman Street, Room 215 <br />Denver, CO 80203 <br />July 7, 2014 <br />William A. Bear <br />Bowie Resources, LLC <br />P.O. Box 483 <br />Paonia, CO 81428 <br />Re: Bowie No. 2 Mine (Permit No. C- 1996 -083) <br />May 2014 VWP Monitoring Results <br />Adequacy Review <br />Dear Mr. Bear: <br />The Division has received and reviewed the May 2014 Vibrating Wire Piezometers (VWPs) <br />Results report for the Bowie No. 2 Mine submitted by J.E. Stover & Associates on behalf of <br />Bowie Resources, LLC (BRL). BRL requested a determination from DRMS whether monthly <br />monitoring of the piezometers would still be required, or resumption of quarterly monitoring <br />might be appropriate. Based on our review of the report and BRL's request, we have the <br />following comments: <br />VWPs installed to measure pore water pressures within Coal Mine Waste Disposal Area No. 2 <br />(Gob Pile #2) at the Bowie No. 2 Mine have been historically monitored on a quarterly basis. <br />Results are submitted with the quarterly monitoring report for coal mine waste piles at the <br />1017.0-20151VZONA Mw <br />During the adequacy review process for TR -85, the Division developed concerns about the slow <br />rate at which pore pressures were dissipating from the upper central portions of CMWDA No. 2. <br />In particular, pressures reported for VWP -08 were within just 3 psi of the level at which the <br />pile's Factor of Safety (FoS) might fall below the minimum required value of 1.5. <br />Given the operator's plan to increase the volume of wet coal mine waste being stored atop the <br />pile, the Division required BRL to commit to a temporary increase in the frequency of VWP <br />monitoring. A commitment to monitor the VWPs monthly from April through October 2014 <br />was provided by J.E. Stover & Associates, on behalf of BRL, in a letter dated April 11, 2014. <br />To date, two monthly VWP monitoring reports have been submitted. Data is collected in the <br />field by Buckhorn Geotech, the company that originally installed the various VWPs. Buckhorn's <br />o1 CO <br />1313 Sherman Street, Room 215, Denver, CO 80203 P 303.866.3567 F 303.832.8106 http: / /mining.state.co.us I t <br />John W. Hickenlooper, Governor Mike King, Executive Director Virginia Brannon, Director <br />