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<br />p~e~ved <br />SUMi~iStS2aE GOLa COFti'ORATION ~ pUG 21 ~ <br />AM ECIiO 8AY COARFANY ~~~p Fi91d Oh1~ <br />P.O. Box 177 Silverton, CO 81433 Wviswn of Minerals & Geela9Y <br />Phone (970) 387-5533 Fax (970) 387-5310 <br />u~ i t~:; <br />August 14, 2002 <br />Mr. Wallace H. Erickson, Environmental Protection Specialist ~/ <br />Division ofMinerals and Geology <br />Department ofNatural Resources <br />701 Camino Del Rio, Room 125 <br />Durango, CO 81301 <br />RE: File No. M-1977-378 ~' <br />TR-025, Stipulation No.3 ~ <br />Dear Mr. Erickson: <br />On March 14, 2001, DMG approved TR-025 with three stipulations. This report is <br />submitted to demonstrate acceptable performance of Bulkhead No.2 and to request <br />performance acceptance by DMG so that installation of Bulkhead No.3 can proceed <br />(Stipulation No.3). <br />The valve on Bulkhead No.2 was closed on August 31, 2001. Since closure Sunnyside <br />has monitored the hydrostatic pressure, pH and sulfate levels behind the bulkhead as <br />required by Stipulation No.3 to demonstrate that design parameters have not been <br />exceeded. A table of the monitoring results and graph of the hydrostatic pressure rise is <br />attached for reference. Sunnyside believes that the graph demonstrates that the defmition <br />of "equilibrium" has been approached and that the design pressure (277 psi), which <br />represents ground surface elevation, will not be exceeded. The pressure was 175 psi on <br />August 15, 2002. <br />As requested in your email received Juiy 31, 2002, Sunnyside has established two more <br />data points for pH and sulfate to demonstrate that the change observed between the <br />