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rr"PITASCA: <br /> Denver, Inc. <br /> Figure 2-5 displays the NNP values of the Phase I samples overlaid on the CFD for the Project <br /> dataset. As illustrated in Figure 2-5, the Phase I samples provide a reasonable representation of <br /> the overall Project waste rock NNP values. <br /> 2.4 PHASE II SAMPLE SELECTION <br /> Itasca identified a subset of 12 of the 29 Phase I samples for further static testing and kinetic <br /> HCTs (Phase II). Table 2-3 indicates which samples were selected for Phase II testing and the <br /> rationale for their selection.The percentage of Phase II samples of each updated rock-type group <br /> is listed in Table 2-2. Each of the rock types represented by the 29 samples from Phase I testing <br /> is also represented in the 12 Phase II samples. <br /> Figure 2-6 illustrates the distribution of the NNP values from the Phase I ABA analyses for the 12 <br /> proposed Phase II samples compared to the NNP calculated from LECOT", data for the entire <br /> population. The 12 samples were selected to both adequately represent the rock types and <br /> represent the range of calculated NNP values from the overall population.As shown in Figure 2-6, <br /> the 12 proposed Phase II samples adequately cover the range of NNP values identified from <br /> LECOTm data for the entire population. In order to more fully assess the AGP of these materials, <br /> five of the 12 proposed Phase II samples (133, B8, B12, PP2, and PP4) were selected for further <br /> testing to represent the materials with NNP values near zero, as these materials approximately <br /> represent the central tendency of the LECOT" database samples. <br /> Samples AP7, PP2, and PP4 were selected for Phase II testing because, while representing the <br /> larger population NNP values, these samples do not contain detectable pyrite but do have <br /> reported AGP. These samples are characterized by a relatively low AGP compared with samples <br /> containing pyrite. The AGP associated with these samples is a result of the nitric acid-extractable <br /> and hot-water-extractable sulfur concentrations that appear to be related to the presence of the <br /> acid-sulfate minerals alunite and jarosite.The proposed Phase II testing of these samples enables <br /> further evaluation of their potential acid generation. <br /> 8 <br />