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<br />The option of operating the San Luis system with pon water <br />recirculation, and with water makeup if required to offset eve orative <br />losses and loss of pore water to the deposited solids, and with the current <br />best techniques for cyanide reduction, should provide a rapid insi t into <br />the likelihood of reaching the permit level of 4 ppm cyanide. <br />The addition of ore to the circuit, without addition of cyanide to ~ewver <br />gold from this feed, means that the mill will not produce a produc (gold) <br />while these tests are in progress. This in itself is incentive to ove to <br />maximum rate and efficiency in reducing the pond cyanide levels t the 4 <br />ppm target so that wnsideration can be given to resuming ~iormal <br />operations with a maintained 4 ppm level of cyanide in the pond. <br />In Dr. Harry Posey's memo to Dr. James Pendleton (June 12, ]9 2), he <br />notes that the question of whether or not to continue plant operat n will <br />be considered at the June 24, 1992 meeting of the Board. My su estivn <br />to operate the plant without the continuous addition of cya ide is <br />wnsistent with a desire to meet permitted cyanide levels of 4 ppm in the <br />shortest possible time and then to address conditions under which those <br />levels can be maintained as "normal" mill operations ++!h cyanide a dition <br />and gold recovery are resumed if permitted. <br />I remain concerned at the prospect of using the San Luis facility as very <br />large scale laboratory to test ways to recover from the out-of-permit evels <br />of caanide in the tailing impoundment, and feel that the risk the <br />wmmunity is real during these tests. <br />However, I submit that the proposal to treat the cyanide containing aters <br />by the above scenario (that is, no addition of cyanide to the reeircu ating <br />waters and thus no gold recovery for what should be a short period o time <br />(if BMG, Degussa, FMC, and Inco projections are correct relati a to <br />cyanide removal rates and technology) presents a reduced risk and rgets <br />reduced caanide levels in minimum time. <br />It is my opinion that the operation of the system without cyanide ad ition <br />in the mill will show us all just how good we can expect cyanide remo al to <br />be with the current technology and will set the stage for assuring that <br />permitted cyanide levels can be maintained in future operations. ese <br />ends are essential to the intent of the work now on-going at San Lui and <br />meeting them with this approach reduces the risk to the couununity d to <br />the environment around the facility. <br />~~-~~l~jLf=~J <br />M061ti92I)EH1 <br />