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• ~ ~ IS <br />Detailed Examination of Selected Samples <br />Tn this category of testing were included the following: <br />Mineralogic analyses by microscopic examination and x-ray diffraction <br />spectroscopy. <br />2. Major and trace element analyses on selected samples from the humidity cell <br />testing. <br />3. Meteoric rinse tests on seven samples of historic waste dump materials from the <br />vicinity of the Cresson project. <br />4. Humidity cell test data on samples in-progress for periods of 6 to ti0 weeks. <br />Data and conclusions reported on the basis of these data are discussed in the following <br />section of this third party review report. <br />Mineralogic Analyses <br />The reported Mineralogic analyses included test results from transmitted and reflected <br />light petrography and from X-ray diffraction patterns. The objective of these tests was to <br />determine what specific minerals were present in the tested samples and to examine the <br />depositional association of these minerals with one another. <br />The thin section analyses of the various samples showed what I think was the expected <br />minerals assemblage. Pyrite was noted in varying amounts and varying degrees of <br />apparent availability for reaction in the samples with higher and more available pyrite <br />presences in the highest sulfur materials. Carbonate minerals were not identified in most <br />of the samples although they were noted in two samples from the higher sulfide zone. <br />Only one sample analysis by a scanning electron approach showed any distinct mineral <br />identification for any of the trace metals in the material (a single 8 micron grain of galena <br />in a pyrite matrix). <br />The majority of the samples (l3 of 20 or about 65%) contained < 0.62% total sulfur while <br />a minority of the materials evaluated (7 of 20 or about 35%) had total sulfur contents <br />ranging from 0.62 to 3.26%. The authors of the report use the sulfur cutoff at 0.62% to <br />separate what they refer to as the oxide zone from the higher sulfur transitional and sulfide <br />zones. While this nomenclature may be considered somewhat arbitrary, it does provide a <br />convenient way to describe variations in the Cresson material and appears to beaz a <br />consistent relationship to the observed depositional character of these materials. <br />The Mineralogic analyses of the Cresson materials provided added validation to <br />earlier assumptions on mineral assemblages present in the deposit and on their <br />relative abundance as a function of location in the deposit. Detection of jarosite in <br />the higher sulfur samples is indicative of the expected oxidation reactions outlined in <br />the section of the report detailing basic chemistry of pyrite oxidation. <br />OMLR951 DEH <br />