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ITASCA: <br /> Denver, Inc. <br /> 3.3.2 Results <br /> Twenty-eight different minerals were identified in the 29 Phase I samples.The identified minerals <br /> are listed in Table 3-3 along with their relative abundances in weight percent. The laboratory <br /> report is provided in Appendix B. As documented in the laboratory report, two peaks visible in <br /> the X-ray pattern could not be positively identified for several samples. These peaks appear to <br /> be related to interstratified kaolinite-illite and/or kaolinite-smectite or other clay minerals. <br /> The mineralogical composition of the Phase I samples is illustrated in Figure 3-5 and listed in <br /> Table 3-3. Potassium feldspar, plagioclase, illite/muscovite 2M1, and pyrite are the most <br /> abundant minerals in the samples.These minerals account for more than half of the composition <br /> of each of the samples and more than 80% of the composition for 27 of the 29 samples. The <br /> carbonate minerals identified in mineralogic testing are shown in Figure 3-6. <br /> Pyrite is the only sulfide mineral identified and is of primary interest because of the AGP <br /> associated with this mineral. Under some circumstances, the sulfate minerals jarosite and <br /> alunite, which were detected less frequently and at lower concentrations, can also contribute to <br /> the AGP, as discussed previously (e.g., Section 3.1.2). These sulfate minerals are associated with <br /> sulfide mineralization,alteration,and weathering.The sulfate minerals gypsum (two samples had <br /> approximately 1%gypsum) and barite (identified at contents of less than 5% in four samples) do <br /> not contribute to AGP. Figure 3-7 illustrates the correlation between pyrite sulfur content <br /> calculated from the XRD analyses and the nitric acid-extractable sulfur from the ABA analyses <br /> (which is attributed to sulfide-sulfur). Figure 3-7 also illustrates the correlation between the <br /> combined pyrite, alunite, and jarosite sulfur content calculated from the XRD analyses and the <br /> nitric acid-extractable sulfur from the ABA analyses. <br /> In summary, the XRD results indicate that the most abundant minerals present in the 29 Phase I <br /> samples are three silicate minerals (potassium feldspar, plagioclase, and illite/muscovite 2M1) <br /> and one sulfide mineral (pyrite). The AGP of the samples is largely controlled by the abundance <br /> 20 <br />