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r 999 <br /> SUNNYSIDE GOLD CORPORATION <br /> AN ECHO DAY COMPANY <br /> P.O. Box 177 .Silverton, CO 81433 <br /> Phone (303) 387-5533 .Telecopy (303) 387-5310 <br /> March 18 , 1993 <br /> !C'Jr 4 71 <br /> Mr . James Stevens // <br /> Colorado Department of Natural Resources 2 2 <br /> Division of Minerals and Geology �993 <br /> 1313 Sherman Street, Room 423 j6 <br /> Denver , CO 802/�13-2273 <br /> RE: File No.t/M-77-378 <br /> San Juan County <br /> Technical Revision (TR 14) Submittal <br /> American Tunnel and Terry Tunnel Hydraulic Seals <br /> Dear Mr . Stevens : <br /> This letter is a Technical Revision submittal to provide bulkhead <br /> designs to replace the conceptual plan (Appendix 2-F Consolidated <br /> Permit (112) Application for the Sunnyside Mine and Mill) presently <br /> in the MLR permit. These designs were prepared by John F. Abel , <br /> Jr . a Colorado P.E . , who has had previous experience with water <br /> impounding Yunnel bulkheads. Attached is a paper co-authored by <br /> him titledVTunnel Bulkheads for Acid Mine Drainage. The submitted <br /> bulkhead designs are similar . <br /> DISCUSSION: <br /> A comparison of the conceptual plan in the permit and this TR is <br /> presented below. <br /> Goal <br /> The conceptual plan submitted in 1987 proposes to place plain <br /> concrete plugs in the American Tunnel and Terry Tunnel . These <br /> plugs are to be placed back in the tunnels far enough so that <br /> additional hydrostatic pressure would have limited effect on the <br /> overburden rock . The goal is to accumulate water within the <br /> underground workings until equilibrium conditions prevail . The <br /> sealed mine conditions will provide water of better quality than <br /> what is produced (without seals) from tunnel discharges. This <br /> impounded water would conceivably enter the near surface ; <br /> joint/fracture system (s) associated with the mine. <br />