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9/30/93 <br />Responses to Comments <br />San Luis Reclamation Evaluation Report <br />Page 17 <br />that all sulfides are chemically reactive and will ~,s <br />generate acid. As a result of the static test c ~ <br />results, BMRI performed kinetic testing of the ~Y <br />material to evaluate actual behavior. The_ kinetic ~,..9' <br />west--data demonstrated that none .of the. .tailings <br />were acidyenerating. Test work was continged until <br />the sulfur was leached to below the test dletection nJct <br />limits to adequately demonstrate that the sulfur `~~~~ <br />present was non-acid generating sulfur forms. `N f <br />The communit of eochemical ex erts reco `~ <br />y g p gryizes the `"w,k~{7xt': T <br />conservative nature of the static test results and '~C <br />the reliability of the kinetic tests. Encldsed is a <br />paper published in connection with a study slponsored <br />by the Canadian government. This paper evaluated <br />the predictions from various acid generatiriq tests <br />against actual field conditions. As discussed in <br />the paper the most accurate predictive test was the <br />humidity cell test which correctly predicted the <br />acid generation of 100$ of the tailings tented. <br />Comment: <br />Third, some of the metal concentrations from the leach tests <br />exceed surface water standards. <br />Response: It is unclear from this response what standards are <br />being applied and what results exceeded these <br />standards. However, even without clarification an <br />analogy of the leach test results to surface water <br />standards is inappropriate for the reasons dliscussed <br />in Section 4 of the Preamble. Based on the <br />conservative nature of the leachability tents, the <br />actual concentrations of species seen in the <br />leachate from such test will be conservative with <br />respect to field conditions. Hence, direct <br />comparison of values in test leachates with water <br />quality criteria at any potential receptor is in <br />appropriate, as the basis for the criteria and the <br />leach solution are totally different. <br />Comment: <br />Page 6, 2. Text indicates that the products of HZOs oxidation <br />of metallocyanide complexes include ammonia and carbonate. It <br />is my understanding that nitrate and or nitrite may also be <br />products of this reaction. It is my further understanding that <br />nitrates in groundwater may be problematic. <br />