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AFR O r , q< 92 ~ 57FY'~ °, d.'~7 <br />• <br />a. We must determine if these requirements apply to the final tailings before <br />reclamation or whether they apply to the tailings-pond itself. If the <br />farmer, then it is possible; if the latter then it cannot occur because: <br />b. Typically in the gold-processing industry tailings Contain 100-2QQ ppm <br />free-cyanide plus some WAD. WaD varies with the metal content of the ore <br />but free-cyanide is inevitable because it is this species that extracts <br />the gold. <br />No matter how large the tailings-pond, nor how long the dwell-time in the <br />pond, there is no known prooess that can, in a continuous operation, <br />reduce free-CN to less than 1 ppm without introducing dire consequences. <br />The permit condition outlined above asks BMG to have afree-Cyanide level <br />of 0.6 ppm max. (4.4-3,8). Further, 4.4 ppm refers to Total, It is <br />impossible to generate 100-200 ppm free-cyanide and convert it to 4.4 <br />total, when total is already 100-200 ppm. <br />This logical inexactitude can easily be rectified by re-defining the <br />standard, for example: <br />Total = x ppm <br />WAD = y ppm <br />Free = i ppm <br />But again, only WAD and Free should concern us since only these generate <br />toxic end-products. Perhaps we should "forget" total. <br />3, Safe Cyanlde Levels <br />Chemically, nobody has yet defined a "safe" level when applied to ggold-processing <br />operations. The nearest definition Comes from the U.S. Fish and Wlildlife Service <br />in their publication "85 (1.23)", which states that Free Cyanide should be below <br />50 ppm. We all know that WAD, although less toxic than Free, is still dangerous, <br />but no WAD toxicity levels are yet in print. <br />4. BEI Suaaestions to BMG and t_he State of Colorado <br />We believe that the following should be true for BMG, San Luis, with the approval <br />of the State of Colorado. <br />a, No wildlife shall die as a result of the existence of San Luis (BMG). <br />b. Free cyanide shall be less than 30 ppm in the tailings ponds (available to <br />waterfowl). <br />N,L„{ ,,, c. True WAD cyanide shall be less than 40 ppm in the tailings ponds (approx. <br />,,.~-~~ + „rA,,± equivalent to 20 Free). <br />