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r <br /> �-ITASCA" <br /> Denver, Inc. <br /> The LECOT" results were used to estimate the distributions of AGPs and ANPs within each rock- <br /> type group. The purpose of this estimation was to facilitate sample selection to ensure that the <br /> samples are reasonably representative of the overall distribution of the rock types associated <br /> with the Project.Two important simplifying assumptions were used for this estimation,and these <br /> assumptions are discussed in the context of the results of the WRCS herein. <br /> The first assumption was that all of the sulfur contributes to the AGP in a manner consistent with <br /> pyrite. This assumption is conservative (tends to overestimate AGP) because in reality some of <br /> the sulfur is associated with minerals such as gypsum that do not result in acid generation. <br /> The second assumption was that all of the carbon contributes to the ANP in a manner consistent <br /> with calcite. This assumption can result in overestimation of ANP because non-neutralizing <br /> carbonate minerals (such as the iron-carbonate mineral siderite and the manganese carbonate <br /> rhodochrosite) are present above trace concentrations. <br /> The results from the ABA testing (Section 3.1) were used to develop a more detailed <br /> characterization of the AGP and ANP and to more precisely relate the LECOT" results to the ABA. <br /> The LECOT" results provide an indication of the overall distribution of carbon and sulfur in the <br /> Project waste rock and were used to ensure that the samples subjected to more rigorous <br /> characterization testing are reasonably representative of the overall rock-type populations. The <br /> distributions of estimated AGP (based on sulfur content) and estimated ANP (based on carbon <br /> content) and the estimated net neutralization potential (NNP) for each rock-type group are <br /> illustrated in Figure 2-2. <br /> Cumulative-frequency distributions (CFDs)for the estimated NNPs of each rock-type group were <br /> plotted in Figure 2-3a to compare the NNP distributions of each of the rock-type groups. As is <br /> apparent in Figure 2-3a,the rock-type groups have similar NNP distributions. <br /> 5 <br />