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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 />August 26, 2013 <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 />Technical Revision No. 80 (TR- 80) <br />Gob Pile #3 Underdrain <br />Dear Mr. Bear: <br />COLORADO <br />ID I V I S I O N O F <br />RECLAMATION <br />MINING <br />SAFETY <br />John W. Hickenlooper <br />Governor <br />Mike King <br />Executive Director <br />Loretta E. Pineda <br />Director <br />The Division has completed a preliminary adequacy review of the technical revision application (TR -80) <br />submitted by Bowie Resources, LLC (BRL) for the Bowie No. 2 Mine. The revision proposes a design for <br />an underdrain at Gob Pile #3 to intercept the seep near the Fire Mountain Canal. We have the following <br />comments and questions regarding the application. <br />1. In the revised text on Page 6, BRL indicates that the design of the rock drain will be an <br />alternative design in accordance with Rule 4.10.3(5). There do not appear to be any obvious <br />departures from the criteria of (1), except perhaps that the proposed cover for the drain is one <br />foot of "common fill" rather than the impermeable fabric layer that is commonly seen. The <br />application fails to address the additional requirements of (5), specifically the "thorough <br />analytical demonstration" regarding applicable static safety factor, stability of the fill, and <br />protection of the surface and groundwater. The Division suggests that BRL reconsider the <br />requirements of (5) and provide the appropriate analytical demonstrations, or withdraw the <br />"alternative design" element. <br />2. In the first paragraph of the Subdrainage System section, on Page 6, the text indicates that the <br />drain will be about 100 feet wide near the seep. The thickness of the drain is inferred to be two <br />feet, based on the area (200 Sq.Ft.) given in the following paragraph. However, it is not clear <br />whether use of filter fabric is also proposed for this wide and tapering upper segment of the <br />drain. Please clarify whether a filter fabric is proposed for the upper portion of the system. <br />3. The first paragraph on Page 7 provides an estimate of the flow rate through the subdrain, and <br />asserts that the cross section provided, together with a 4" perforated pipe, will have sufficient <br />flow capacity for any seepage that might occur from the Fire Mountain Canal. We concur with <br />this analysis, but do have one comment: the text does not describe where the discharge from <br />the drain will go. Based on Map 21 -1, it appears that the drain pipe may outlet into ditch D -J3. <br />Please review, and revise the text to clarify where the outfall of the underdrain will be. <br />4. On revised Map 21 -1 Sheet 1, a typical section of the proposed subdrain is provided in the lower <br />right -hand corner. Please provide a note indicating the type of material composing the rock <br />drain. (The text states it will be %" screened or washed rock.) <br />Office of Office of <br />Mined Land Reclamation Denver • Grand Junction • Durango Active and Inactive Mines <br />