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23 is Appendix A of Appendix 1, Volume I! of the Amendment No. 8 document and as presented in Attachment ] 1, very little sulfur reports to [he residual fraction for Cripple Creek samples, so jarosite is not ahtttidant. larosite is uNikely to be abundant since it is thermodynamically unsia6le at pH values greater than 3.5 and only a small traction of the CC&V rocks show pH values below 3.5: The samples are not expected to contain acid sulfate minerals (such as melanteri[e (Fe(II)SO4. 7HzO), rhomtxx:lase (NyOZi?e(A1)(SOak• zHrO, coquimbi[e (Fe(fllyr(SO4)3. 9H_O), and iomeri[e (Fe(III}rFe(Il)(SO4)a• 14H_O) because those minerals form at pH values below about 3.0. Even if acid sulfate minerals were presen[ in overburden rnaterials, and the calculaeed NNP values in the overburden were lower than calculated the dentotistra[ed neutral'tza[ion cspaciry within the deep diatrerne system is more than sufficient to neutralize the resultam acidity. . ~ , ~. In order to test this hypothesis, a conservative acidity model of the SGOSA and diatreme sys[em was developed (Attachnicnt 15), In this model, the mass weighted NNP of the.overall system rept'esented by the overburden and diatreme units above the Cazlton Tunnel was calculated. Further, aU sulfur within the SGOSA was assumed ro be acid gerterating (a conservative assumption given the documented presence of gypsum-anhydrite, barite and celesfte within the overburden). The overall NNP value was calculated as +18.1 t/1,D00 t even with the assumption the[ all sulfur was aad generating. Additionally, the'madel showed chat the maximum acidity that could be produced within the SGOSA in any single year would be exposed to ample aikaGnity as the water flowed through the diatreme, The large reservoh of alkalinity within the system provides an ample factor of safety. This is evident In the ratio of alkalinity to aad production in the deep diatreme. The ratio is over 1,000 the first year after placement of overburden and increases each year thereafter. The model is included as Attachment 15 of this suttnittal. 4. r.ANP. The ANP method is not stated For the system at hand considering the mineralogical ' _` ~ ^ '~'camposition of the diatreme described in Lindgren and Ransame, it is noted that ANP '=calculations based on carbon and sulfur. whereby the carbon is Iota! carbon assumed to be 'either calcite or dolomite and total sulfur values is assumed ro be sulfide sulfur would be a '•'^preferable method .:77[e Operator should desnibe the AGP and ANP methods used jot the static tests given to rAppendiz A. Jf the carbonate minerals Jndttde an appreciable percent of either siderite or ankerite, the ANP should be at(justed accordingly. Utotal carbon tests were run, and ljthe rock .;contains carbon species other than carbonates, those should be repotted !f the test methods ~einployed tirrations or other neutralization reactions that would include silicate btiffering, the " ANP values should be re-examined Absent this, the Operator should address the question in a narrative or in further calculations showing that, high estimated NNP values aside, the system 'Brill will be able to minimize impactr ra the hydrologic balance. Response: The bulk of the carbonate is known to be dolomite and calcite, and neither siderite tuu artkaite have heeii identified or reported (Lindgren and Ransome, 1906). Tile test method employed for ANP determiii'ation was the 9abek ~ al (1978) method. Altdough some silicate minerals tray contribute to the i4iVp i[teasured by the Sobek method, in the experience of CCBtV's experts inclusion of such minerals' is appropriate since they will provide acid neutralization for solutions that provide adequate confaei times (af days to weeks>. 'the close agreemet[t between the ANP and measured carbon level (sec response to the comment in Section VII.M.3 above) demonstrates that carbonates (limestone and dolomite) are the dominant minerals thac contribute to ruutralization as qualified in the ANP tests. 5. The geological and mineralogical presentations show that average NNP al the Cresson pit is `somewhat strongly positive (acid neutralizing) while the average NNP far the proposed North ;.