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16 <br /> LABORATORY STUDIES WITH ANAL MINING WASTES <br /> Sulfur fractionation was performed on all three materials to <br /> determine pyritic sulfur and resultant ferrous iron contents. Table 7 <br /> contains the sulfur form data for each material where the levels of <br /> pyritic sulfur are in decreasing amounts. Also, the materials are <br /> listed in order of increased weathering. <br /> Table 7. Sulfur Fraction- Determination <br /> Pyritic Sulfate Organic Total <br /> Sulfur Sulfur Sulfur Sulfur <br /> X X X X <br /> Copper 47.500 0.400 0.810 48.700 <br /> Nickel 5.430 2.310 3.160 10.900 <br /> Uranium 0.321 0.992 0.017 1.330 <br /> Figures 8 and 9 represent acidity data obtained from eight weeks <br /> of incubation testing for tailing samples of copper, uranium and nickel <br /> ore <br /> s, respectively. As the data represent separate samples from each <br /> incubation period, the results are cumulative and must be compensated <br /> for by adjusting to a time zero baseline (Sobek, et al, 1986; Sobek, <br /> 1980). <br /> Data trends established for copper (Figure 8) indicate that <br /> subsequent to four weeks of incubation, acid production was minimal. A <br /> final reduction in acidity at week eight of >50% averaged for the <br /> --treated samples was obtained. <br /> Induced leachates from uranium tailings (Figure'8) suggested an <br /> immediate response to the bactericide was obtained, evidenced by 70% <br /> reduction in acid production at the - second week of incubation. <br /> However, • trends established through week eight , indicate- .a return <br /> towards control level acidity values. In contrast, .results on nickel <br /> tailings (Figure 9) indicate no reduction in acid production by the <br /> treatment was obtained during the test period. <br /> Acidified ferric ion solutions are effective lixiviants for many <br /> metals of sulfide and oxide ores. On this basis, the copper ore <br /> tailings possessing the highest pyritic sulfur level ,would-be expected <br /> to produce the most acidity. Data presented in Figures "8-9 contradict <br /> this prediction, showing a significantly higher�level`of acidity for <br /> uranium ore samples. Nickel tailing leachates produced acidity levels <br /> at rates relative to uranium and copper tailings in agreement with <br /> pyritic sulfur analysis. <br />