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- ~ ~ ~II II~II~II~II~~ II~ <br />BATTLE MOUNTAIN COLD COMPANY <br />R"`'-` <br />R 3 ~ 1g9r '° o ~`"" <br />March 24, 1992 ~p <br />~ilned''~ild . <br />.t0,, .n <br />Mr. Larry Oehler <br />Reclamation Specialist <br />Mined Land Reclamation Division <br />1313 Sherman St., Rm. 215 <br />Denver, CO 80203-2273 <br />Dear Mr. Oehler: <br />The approved processing design for the San Lu s project <br />incorporated the use of a cyanide tailings detoxification system <br />referred to as AVR. The AVR system has been in use since the <br />mill began operating last year and has consistently ac ieved the <br />pH compliance criteria as set forth in the approved ermit for <br />the facility. <br />The tailings pond was frozen over this past win er due to <br />one of the coldest winters on record for the San Lu s valley. <br />This past month as our pond began to thaw, Battl Mountain <br />Resources' ("BMR") sampling of cyanide concentration revealed <br />levels higher.than anticipated. <br />BMR believes that an expeditious response to t e current <br />tailings pond cyanide levels is appropriate. We ropose to <br />reduce the cyanide levels in the pond through the a dition of <br />zinc ferrous sulfate. This chemical is commonly sed as a <br />cyanide detoxification chemical in the mining Indust y and the <br />by-products of the detoxification reaction have been de onstrated <br />to be stable and environmentally benign. In our view, the <br />procedure should be implemented as soon as possible ecause of <br />the potential attraction of open water to waterfowl uring the <br />spring migration. Therefore, BMR intends to commenc addition <br />of the zinc ferrous sulfate no later than March 31, 19 2. Please <br />contact me immediately if you have any questions o concerns <br />whatsoever with this proposal. <br />For the longer term, BMR is currently conductingan overall <br />performance evaluation of the AVR system and is d termining <br />whether alternative or additional detoxification techn logy could <br />be appropriate for the facility. We anticipate that evaluation <br />to be completed on or about May 1, 1992. BMR intends~to provide <br />your office with the results of the study along' with its <br />conclusions regarding performance of the system andpotential <br />333 CLAY STREET 42ND FLOOR HOUSTON, TEXAS 77002-0103 (713) 650-6400 FAX (713) 6504636 LE% 763604 <br />