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Bulldog Mine Tailings Ponds Evaluation <br />5.1.2 Mineralogic Analyses <br />• Mineralogic analyses were performed on tailings solids to search for secondary minerals which <br />are by-products of acid-generating sulfide (primarily pyrite) oxidation reactions. The oxidation <br />of pyrite (FeSZ) produces secondary iron-oxyhydroxide and sulfate phases such as goethite <br />(Fe0(OH)), ferrihydrite (Fe(OH)3), and jazosite (KFe3(SOQ)Z(OH)6). These secondary minerals <br />aze typically closely associated with the original sulfide minerals from which they are derived, <br />and occur as grain coatings and/or rims on precursor sulfide minerals. The presence of these <br />secondary minerals provides direct evidence of oxidation reactions within the tailings. The <br />observed absence of these by-product phases indicates that the sulfide minerals aze essentially <br />stable in their current environment. <br />5.1.2.1 Mineralogic Analyses Methods <br />The primary mineralogy of the tailings and the mineralogic transformations that have occurred <br />since tailings deposition were chazacterized using optical and ore microscopy techniques, and x- <br />ray diffraction (XRD). The intervals investigated in the mineralogic analyses are the same <br />• intervals which were utilized in the ABA analyses described above and shown in Table S.l; <br />therefore, the results of ABA analyses can be directly compazed to mineralogic and textural <br />evidence of acidification within the materials. <br />5.1.2.2 X-ray Diffraction Analyses <br />The x-ray diffraction analyses included bulk whole rock analyses and oriented clay separate <br />analyses. The bulk analyses indicate that the majority of the tailings aze composed of quartz and <br />baiite with minor amounts of feldspar. Clay analyses indicate that the fine grain materials aze <br />also primarily quartz and barite with minor amounts of mixed layer illite/smectite clay and a <br />trace amount of kaolinite. Evidence of pyrite, or other sulfide minerals, and/or iron <br />oxyhydroxides was absent in the x-ray diffractograms. The lower limit for the identification of <br />minerals by x-ray diffraction is approximately three percent; based on the amount of pyrite <br />estimated from ABA analyses (0.24 percent to 2.14 percent pyritic sulfw by weight, Appendix <br />C), these results are not surprising. <br />• <br />Nornestuke ,Mining Company Shepherd dlil(er. /rtc. <br />p:v--)inn„ump p.. 26 dpri( l1. l99% <br />