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<br />~ STAT'~OF COLORADO <br />MINED LAND RECLAMATION DIVISION aF ~o~ <br />Department of Natural Resources F ~4sg <br />1313 Sherman St., Room 215 .. o <br />Denver. CO 80203 ./~. <br />303 866-3567 +re~b+ <br />Fn X: 303 832-8706 <br />RcY Rangr, <br />Gwamar <br />June 8 , 1992 Michael B. Lang, <br />Division Director <br />Mr. Andre J. Douchane <br />Battle Mountain Gold Company <br />5670 Greenwood Plaza Blvd. Ste 106 <br />Englewood, CO 80111 <br />RE: Adequacy Review Response: Technical Revision No. 007; Tailings <br />Cyanide Detoxification Using Hydrogen Peroxide; Battle <br />Mountain Gold Company; San Luis Project; Permit No. M-88-112. <br />Dear Mr. Douchane: <br />Your 3 June 1992 response to our adequacy concerns regarding the <br />above named technical revision is deficient in three cgmponents. <br />1. Your comment 1. First paragraph. <br />In a 13 May 1992 letter from Cliff Shutt to Art Lefler, Mr. <br />Shutt indicates that the pond is "perfectly homogeneous," that <br />a sample taken from anywhere in the pond would "be accurate <br />within 5%," and implies that all of the analyses are identical <br />within the range of normal sampling and analytical error. <br />However, these remarks are not substantiated by data in the <br />report. <br />The ranges of WAD cyanide data expressed as a percent of the <br />mean are similar for both the Acculabs.data set ahd the San <br />Luis data sets; both are approximately 20%. Furthermore, the <br />trends of the data, as shown on profiles, are similar for both <br />data sets. These facts, 2 believe, indicate that variations <br />in the pond are real rather than random. <br />A N-S profile through sample stations 4, 5, and 6 shows that <br />WAD cyanide concentrations increase with depth on both the <br />data sets. A N-S profile thorugh sample stations 1, 2, and 3 <br />shows a high value in the shallow part of the northern sample <br />station, and similar to slightly higher values with depth at <br />the other two sampling stations. These, I believe are <br />compatible with an interpretation that high values occur near <br />the discharge point, and that cyanide sinks to the bottom <br />owing to its high density relative to water. <br />Sampling and analytical errors are not given, and were <br />apparently not requested from the labs, so there can have been <br />