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1 <br />reactions would support the conceptual ability of the basic minerals in the Cresson materials <br />to react with acidic contacting waters and thus to mitigate development of net high acidic <br />drainage from the area. <br />Dr. Hyatt also agrees that pyrite is "the primary potential acid forming mineral" and that <br />"the materials which were highest in total sulfur content were also highest in sulfide sulfur." <br />He goes on to state, "Thus, the potential for acid generation is directly related to the amount <br />of total sulfur in the sample." <br />Dr. Hyatt recognized that "all of the samples tested contained low levels (typically less than <br />200 ppm or less than 0.02%) of any environmentally significant trace elements." In the text, <br />Dr. Hyatt observes a lack of discussion of the chemistry of zinc or other trace metals vis-a- <br />vis potential release, and raises the question of whether the release originates from <br />solubilized pyrite or from other trace sulfides or other minerals. First, as Dr. Hyatt also <br />recognizes, the concentrations of trace elements in effluent from the humidity cells is quite <br />low. He states "At the low levels which the trace elements are present, less that 100 ppm <br />for nearly all elements in nearly all samples." He also states "The absence of substantial <br />information on associations of the trace metals with pyrite or other more abundant species is <br />not surprising based on the low level of these trace elements in the Cresson material." In <br />another portion of his analysis, Dr. Hyatt notes "The test data in this area support the <br />contention that the samples are in fact low in most trace metals and have sulfur contents that <br />span a reasonable range from 0.02 to 1.86%. Second, the pyrite releases iron and sulfur and <br />any other trace metals must be derived from other minerals. Very few sulfide minerals are <br />identified in the samples. Sphalerite is a likely source of zinc. Furthermore, Dr. Hyatt <br />concludes that "In cases where corroborative data on trace metals in selected samples were <br />presented from analytical techniques with lower detection limits, the concentration of metals <br />such as Cd were demonstrated to be generally below regulatory limits." We believe that the <br />chemistry of zinc or other trace metals vis-a-vis potential release has been discussed as much <br />as the low levels allow and require, and it would appear that Dr. Hyatt comes to the same <br />conclusion. <br />Dr Hyatt also concludes that "The mineralogical analyses of Cresson materials provided <br />added validation to earlier assumptions on mineral assemblages present in the deposit and on <br />their relative abundance as a function of location in the deposit. Detection of jarosite in the <br />higher sulfur samples is indicative of the expected oxidation reactions outlined in the section <br />of the report detailing basic chemistry of pyrite oxidation." <br />Dr. Hyatt raises the possibility of the roles of weathering processes such as "different <br />exposure to water flow velocities, cyclic wetting and drying cycles, bacterial impacts, and <br />freeze-thaw cycles" as factors that "may all impact the net outcome of acid generation and <br />neutralization reactions." While these generic variables may serve to decrease, or increase, <br />acid generation or metals mobilization, there is no evidence from the information gathered <br />for the CC&V operation that these are important variables that would affect the extrapolation <br />of test data to field conditions. The depositional state of the Cresson Mine overburden is not <br />2 <br />