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M ~ <br />Memo - BMG Tailings Detoxification <br />BEI Study and Proposal <br />page 2 <br />The cyanide concentrations within the tailings must attain total cyanide <br />levels of less 4.4 ppm or less, and the weak acid dissociable levels of <br />less than 3.8 ppm. The violation is not abated until these <br />concentrations are attained. <br />(2) The "Cytox" treatment process is relatively unproven. BEI should provide <br />the Division with a detailed list of references for previous applications <br />of the "Cytox" chemicals, including professional contacts. Further, BMG <br />should retain the BEI, as the design engineer, to supervize the project, <br />monitor the performance, and prepare a final report evaluating the <br />success of the application. <br />(3) BEI and BMG have indicated that the project should require approximately <br />two weeks to complete. BMG must provide a detailed schedule for <br />implementation of the technical revision. The schedule should indicate <br />start date, any important interim events, and a completion date. BMG <br />should update the Division daily as to progress of the project. <br />(4) BMG must conduct thorough monitoring of the process to verify trhe <br />progress and final result of the project. At a minimum, BMG should <br />monitor total, free and W.A.D. cyanide levels at the processing plant <br />slurry outfall and at approved selected locations within the tailings <br />area, on a daily frequency. In addition, on a weekly frequency, BMG <br />should sample and determine the detailed metallic constituency of the <br />W.A.D. cyanide at the same locations. This monitoring should continue <br />until the tailings have reached the compliance levels specified in <br />item (1) above. <br />(5) BMG is responsible for the solution of any environmental consequences of <br />their remedial action. <br />In additoon, BMG must expeditiously complete a comprehensive reevaluation of <br />the chemical constituency of their modified tailings, including an evaluation <br />of the potential environmental impact of those tailings. I suspect that the <br />processing complications caused by the ore chemistry is resulting in an <br />unanticipated elevated level of a selection of metallic elements within the <br />tailings. The reclamation implications of this occurrence can be <br />significant. Finally, if the Division determines it to be appropriate, we <br />should require BMG to amend their existing reclamation plan and permit for the <br />tailings disposal area. <br />I have prepared a broader set of abatement requirements for imposition upon <br />the NOPV issued March 31, 1992, which I have attached for your consideration. <br />attachment: <br />cc: Bruce Humphries <br />Mike Long <br />Jim Stevens <br />JP/jP <br />Doc. No: 2362E <br />