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<br />John Hazdaway <br />-3- <br /> <br />May 30, 1995 <br />adequately in the May 2 Letter. Please identify the samples, explain how they were collected, <br />and provide any other pertinent information that would indicate that these samples aze <br />representative of the heap leach mass as a whole, if in fact they are to be used for permit- <br />specific uses that will require representative sampling. <br />Apr 13 Letter. <br />Use of Pad #1 Material for Proposed Applications. It is proposed that material from Pad 2 "will <br />be used to construct the Phase II toe berm, the Highway 67 realignment embankment, and <br />will be used as a source of Select Structural Fill for the downstream face of Phase I Toe Berm," <br />r;- <br />Notwithstanding that the geochemical assessment reported in Attachment #1 may be'non- <br />representative or inappropriate, and proceeding on the assumption that all units are in "ue1L'" <br />the results indicate that the Pad #1 material has the capacity to produce toxic drainage. [Toxic <br />drainage in this context is taken to be that having water quality parameters which exceed the <br />proposed "numeric standards" shown in the Stream Classifications and Water Quality <br />Standards of the WQCC Proposal. The "Temporary Modifications and Qualifiers" were not <br />applied for this assessment. (See later discussion for explanation.)] <br />A comparison of data in Attachment 1 and the proposed "numeric standards" indicates there <br />are water quality exceedances for pH, CN, NH„ NOZ, Cl. Based on the available geochemical <br />data and knowledge that Pad #2 has not been completely rinsed, the Division must conclude <br />that the Pad #1 material is geochemically unsuitable for any of the proposed uses identified in <br />the May 2 Letter. Use of the Pad #2 materials in those locations apparently would cause <br />discharges to Arequa Gulch to exceed the proposed "numeric standards" identified in the <br />WQCC Proposal. <br />Responses to DMG's letter of Apri( 2, 1995. <br />1. All of the materials identified on page 4 of the May 2 letter, have been reviewed, and <br />assessments were made on the basis of study and consideration of all of those. <br />The remaining arguments and refutations expressed in this section do not compel the Division <br />to revise previous interpretations about either the general state of the Cripple Creek ore and <br />waste, the standards by which DMG must assess leaching tests, the results of the tests <br />themselves, or the manner by which the leaching tesu were used to detenmine whether the <br />Cripple Creek ores and waste have or will develop the potential to generate acid and toxic <br />materials. <br />The argument, "ambient" water quality in Arequa Gulch should become the applicable water <br />quality standard, would be compelling if it could be shown that the long-term standards which <br />will be applicable to discharges to Arequa Gulch will be the ambient standazds. This is not <br />