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.:. ~ • ~ • 22 <br />While it is a more speculative possibility, the data on acid neutralization enhancement by <br />grinding of the overburden materials does at least suggest some crushing/grinding of the <br />overburden with both Type A and Type B materials being combined might minimize the <br />potential for net acid development ant tals mobilization in the disposal pits. As finer <br />ground, mixed, overburden materials 8r Asited in the pits, the fi(I in these pits more <br />closely approximates the post-depositional vials in the Cresson project area and we <br />might expect the composite pit fill would showi`'!°he acid neutralization and metals fixing <br />properties of this in-place material. <br />While effluent from the humidity cells is similar in quality to samples of water from Arequa <br />Gulch, in terms of the range of pH and metals observed in both, the effluent does not <br />compare as favorably with Water Quality standards for either pH or metals. The decision <br />on which target water quality to focus on as a goal for drainages from Cresson project <br />materials is not a chemical or geochemical one but rather a policy or regulatory issue. <br />Finally, if materials are placed in the [ronclad and Globe Hill pits, it appears to me that any <br />discharge from these areas may enter Squaw Gulch and, if this is the case, then additional <br />sampling in Squaw Gulch will probably be necessary. If there is any communication of the <br />drainage from the disposal pits with other surface or underground water conduits, <br />sampling of these receptors will also be needed. <br />OMI.R9S IDEH <br />