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<br />dilution from spring floods. Also, the high degree of QA failures makes most of the data suspect. <br />The cyanide results are interesting, and problematic. Firstly, the results do not indicate which <br />form of cyanide was analyzed; [would assume from first principles that the analyses aze of total <br />cyanide, but that is not shown on the data reports. Even so, it is highly unusual for cyanide to <br />occur in any form in tailings that aze almost 50 years ofd. Evidently the soils, which were <br />collected from just one foot depth, have extremely low permeabilities; otherwise, the cyanide <br />should have volatilized long ago. <br />Although there is reason to suspect that the cyanide data are not correct, on the chance that they <br />aze indeed correct, this bodes well for the environment because it indicates that acid rock <br />drainage is likely not to be well developed due to the extremely low permeability of the soils. <br />Whether this will make a difference to processing methods can only be determined through <br />bench scale tests. Also, this may be a local phenomenon as the tails likely have variable <br />mineralogy and permeabilities throughout, but the initial indications offer positive <br />interpretations. <br />Whether the tails will present environmental problems in the future if they are moved, re-mined, <br />or otherwise disturbed, I cannot really determine from the data. The XRF scans, which are <br />intended to represent potential adverse environmental conditions, cannot really be used for such <br />interpretations. Metals which aze locked in clay minerals and feldspars for instance are not <br />environmentally available except under extreme pH conditions, so the XRF method cannot be <br />used to predict environmental consequences. (I always wonder why the EPA used this method <br />rather than some more appropriate leaching method, especially in light of the dubious <br />interpretive results that always accompany the analyses.) Also, because there is no attendant <br />sulfur data, one cannot know whether there is a potential for acidification of the tails and <br />mobilization of metals or not. <br />Analytical, field, and QA uncertainties notwithstanding, the concentrations or several metals do <br />appeaz elevated, relative to whole earth values, in most of the tails. Also, elevated metal <br />concentrations appear for a wide range of elements. This fact suggests a wide mix of ore host <br />rocks, as indicated in the text. I would expect in general that a single deposit, such as that at <br />Cripple Creek, would have elevated concentrations for a small suite of metals, but not for the <br />host of metals indicated in the data. The degree to which these metals may become mobilized in <br />the process of remining will depend on the mining methods, and most importantly the exposure <br />of grains to surface water and oxygen. <br />In summary, there is not enough information to tell whether the tails aze an adverse or potential <br />adverse environmental source or not. Surface water contamination from the site, if it exists, may <br />have been diluted by high spring flows. Cyanide concentrations at any level in tailings that are <br />nearly 50 years old should be highly unusual, so the data should be viewed skeptically. Elevated <br />lead concentrations in a few wells could be from lead in the plumbing, it could be natural, or it <br />could be from the tails, so follow-up work is needed to determine the source. Elevated metals in <br />post-tails sediment relative to the site upstream, while indicative of tailings deposition to the <br />stream, cannot be used to discern contaminant levels. This also cannot be used to test whether <br />