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<br />R. G. OTTO & ASSOCIATES <br />~;"y <br />Uranium levels typically were 20% or less of the 0.59 ~qm/1 <br />Standard. Copper concentrations in the ground water did exceed <br />the Water Quality Standard oa three of five occasions .but only by <br />amounts of 1 to 5 uqm/1. Similar, "high" concentratio~zs of copper <br />were frequently observed at the upstream surface water sampling <br />location (see "Surface Water Assessment", Table 7) and the ground <br />water levels appear to be a reflection of natural copper levels in <br />the drainage rather than as impact associated with the waste rock <br />piles. <br />Some additional inferences can be made about the likelihood of <br />,~~;.~ impacts of the waste rock pile oa ground water quality oa the <br />~i <br />basis of personal observations made over the five-plus years that <br />I have worked at the site. The first relates to the sources of <br />water for input to the pile. The west waste rock pile sits <br />partially on the alluvial soils that make up the floor of the <br />Ralston Creek canyon and partially on the colluvial soils that <br />make up the canyon side. That portion of the pile that rests on <br />the canyon floor is elevated well above the level of stream flow, <br />even during the periods of extreme runoff that have occurred in <br />the past several years. <br />'~:a' <br />?< <br />