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1111111111111111III <br /> 999 <br /> St?i1 NYSIDE GOLD CORPORATI <br /> C AN ECHO 8AY COMPANY <br /> P.O. Box 177 .Silverton, CO 81433 <br /> Phone (303) 387-5533 .Telecopy (303) 387-5310 <br /> March 25, 1993 <br /> �� 3 U 1993 <br /> Mr . James Stevens <br /> Colorado Division of Natural Resources ,w" "... ..,�y <br /> Division of Minerals and Geology <br /> 1313 Sherman Street, Room 423 <br /> Denver, CO 80203-2273 / ) <br /> RE: File No. 4 77-378 T <br /> Syn Juan County <br /> drological and Hydrochemical Studies, Sunnyside Mine <br /> Dear Mr . Stevens : <br /> Sunnyside Gold Corporation (SGC) commissioned studies to evaluate <br /> the concept of placing concrete plugs in the American Tunnel and <br /> Terry Tunnel. This concept is in the Sunnyside Mine MLR permit to <br /> be implemented upon final reclamation. The studies were performed <br /> by Simon Hydro-Search and consist of a general hydrology/water <br /> chemistry study of the Sunnyside Mine and surrounding area and an <br /> evaluation of the bulkheads (hydraulic and hydrochemical ) . These <br /> studies are enclosed for your information. <br /> A discussion of the study results is presented below: <br /> 1) The probable flow direction for groundwater after impoundment <br /> will be from the Sunnyside Mine area . towards Cement Creek . <br /> This was the most probable flow direction before mining <br /> occurred. <br /> 2) The expected equilibrium mine pool elevation is in the <br /> vicinity of 11 , 500 feet . If this is the case, any bulkhead <br /> design based on the topographic limit (Lake Emma elevation of <br /> 12, 210 feet) will have an additional factor of safety against <br /> failure due to reduced fluid load conditions (1 . 84 for the <br /> American Tunnel bulkhead, 25. 6 for the Terry Tunnel bulkhead <br /> and the F-Level and B-Level Brenneman bulkheads would not <br /> impound water giving an infinite factor of safety) . If mine <br /> flooding occurs as modeled , it will take approximately 10 <br /> years to reach 860 of equilibrium and well over 20 years to <br /> reach equilibrium. This model used a lower equilibrium level <br /> (11, 370 feet) but should show the expected trend. <br />