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9/30/93 <br />Responses to Comments <br />San Luis Reclamation Evaluation Report <br />Page 10 <br />test will be conservative with respect to field conditions and <br />direct comparison of values in test leachates with water <br />quality criteria in any potential receptor is not appropriate, <br />as the basis for the criteria and the leach solution are <br />totally different. <br />5.0 Geochemical Test Results <br />The test results are discussed in detail in Section 3.0 of the <br />Reclamation Evaluation Report. The test results indicted that <br />the operational tailings have similar characteristics to the <br />pre-operational test results. The operational tailings have a <br />higher acid neutralizing potential and a similar lack of <br />leachable metals. The operational tailings indicated a higher <br />leachability for some cations and anions, particularly sulfate. <br />This is a result of the detoxification chemicals used. <br />The pre-operational data did not indicate acid generation in <br />the kinetic tests and the quarterly test data also has not <br />indicated acid generation, however BMRI went ahead and <br />conducted kinetic tests to verify that data was indeed correct. <br />As a result of the static test results, BMRI performed kinetic <br />testing of the material to evaluate actual behavidr. The <br />kinetic test data demonstrated that none of the tailiJngs were <br />acid generating. When the Reclamation Evaluation Report was <br />submitted, humidity cell testing was ongoing. BMRI's <br />geochemical expert believed that the tests should continue <br />until sulfate in the leachate was below the test detection <br />limit. BMRI has received additional data on the humidity cell <br />testing since the Report was submitted. This data is included <br />as Attachment 2. A review of this data shows that the pH of <br />all leachates continues to remain near neutral and there is <br />leachable alkalinity. Where low levels of acidity are ,present, <br />it is being adequately buffered by the alkalinity. The near <br />constant pH values throughout the testing combined with <br />sustainable leachable alkalinity demonstrate that the samples <br />are not acid generating. <br />