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M1983-141 Amendment 2 <br />Mount Royale Ventures, LLC <br />9145 Sunshine Canyon Dr. <br />Boulder, CO 80302 <br />Telephone: 720 565-3448 <br />Fax: 720 565-3497 <br />February 7, 2006 <br />Mr. Thomas A. Schreiner <br />Environmental Protection Specialist <br />Division of Minerals and Geology <br />1313 Sherman St., Room 215 <br />Denver, Colorado 80203 <br />Page 1 of 4 <br /> <br />FEB G 6 ZuU6 <br />Division of Minerals and Geology <br />RE: M-1983-141, AM-2 Adequacy Response Concerns Pursuant to Fax Dated <br />February 3, 2006 ~'/qss ~ lZeviSiorl ~Pz-S2sf.~ f~n'1-~ <br />Deaz Mr. Schreiner: <br />Mount Royale Ventures, LLC (MRV) would like to provide additional information <br />regazding two of the three (3) issues raised in Mazk Steen's meeting with the Division on <br />February 3, 2006. <br />1, Information regarding the Cash Mine bulkhead designs for mine closure upon <br />final reclamation. <br />MRV proposes the installation of two (2) bulkheads (hydraulic seals) for the purpose of <br />sealing the mine and any water that may accumu]ate within the mine underground. This <br />is in accordance with the Mine's zero dischazge operation and subsequent reclamation. <br />One bulkhead will be installed at or neaz the grade-break in the newly developed <br />workings, just outby of the pre-law, historic workings (see attached map} at a distance of <br />330 feet from the portal. This is at a point where the ground mass is very competent with <br />little or no fissures or fractures. The drift size is approximately 8 feet by 8 feet. The <br />elevation difference between the sill of the drift and the highest ever observed water level <br />within the Cash Mine workings (mid-drift of the first (125) level) is approximately 106 <br />feet. Drift dimensions are 8 feet by 8 feet. Ground cover at this location is <br />approximately 149 feet. Typical concrete plug lengths for adequate water seal at the <br />rock/concrete interface range from 5-12 feet in length (in Colorado, in compazable <br />situations). MRV proposes anon-reinforced concrete plug with a total length of 10 feet or <br />less. No perimeter grouting should be necessary. <br />A second bulkhead will be installed at approximately 140 feet inby of the portal to <br />contain any potential inflow in the azea outby of the main hydraulic seal. This seal will <br />be subjected to a maximum static head of 65 feet. Drift dimensions aze again, 8 feet by 8 <br />