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waste pile. Although many factors go into making a mine-waste leachate potentially toxic to the <br />environment, for the purposes of this investigation, I used what I consider major contributing factors for <br />potential toxicity. These factors are leachate pH, leachate conductivity, leachate sulfate, and, finally, the <br />sum of concentrations of selected leachate metals (Al, Cd, Cu, Fe, Mn, Ni, Pb, and Zn). For this ranking <br />procedure, each mine-waste leachate was ranked for each of these four parameters. Each site was given a <br />rank ranging from 1 to 13 (13 is the total number of sites included in this study) for each factor listed <br />above. A rank of 1 represents the worst site (most impacted) for that particular factor, whereas a rank of 13 <br />represents the least impacted site for that factor. As an example, a mine-waste-producing leachate with the <br />lowest pH of all 13 sites would get a ranking of "1." If the same mine-waste leachate were 5th highest in <br />leachate conductivity, it would receive a "5" for that parameter. The same leachate would be ranked for <br />sulfate and sum of metals (listed above). Cumulative results from all these tests would then be totaled. <br />After all sites are tallied in this manner, the totals for all sites are ranked. The mine-waste leachate with the <br />lowest cumulative score would then be ranked first in the probability that, should runoff occur, its effluent <br />would have the most likely possibility of negatively affecting water quality should its effluent reach a water <br />body. All other sites are ranked accordingly. <br />Using the ranking scheme in this way allows the investigator to see which mine-waste piles are <br />potentially the worst point-source contributors and which basins have problem sites. <br />It should be noted that this ranking scheme only relates and pertains to the mine-waste runoff <br />geochemistry because, once effluent from any of these sites enters a drainage system and is mixed with <br />other waters, a multitude of changes both positive and (or) negative may occur in the water body. <br />Table 2 shows mine-waste rankings using short-term leaching characteristics (5-minute test). This <br />ranking indicates which sites produce the most toxic leachate if the piles were subject to a meteorological <br />event that produces runoff. The Santiago mine-waste is ranked first, followed by the Waldorf mine-waste. <br />These two sites are located in the Leavenworth Creek drainage. The Togo mine-waste, located in the upper <br />Snake River, was ranked third. It is important to note that the Santiago mine-waste also produced leachate <br />with detectable mercury, the only site in this study to do so. <br />Table 2 Mine-waste rankings for potential effects of runoff due to an event such as a thunderstorm (5-minute leach test) <br />for 13 mine-wastes sampled. <br />Table 3 shows mine-waste rankings using longer term leaching characteristics (18-hour test). This <br />ranking indicates which sites produce the most toxic leachate after being agitated and leached for an <br />extended period of time. These rankings are generally the same as those for the 5-minute leach test. <br />Leachate from the Waldorf mine-waste was shown to have the most toxic geochemical profile according to <br />the parameters explained above. The Togo mine-waste was second, followed by the Santiago. <br />Table 3. Mine-waste rankings for potential effects of runoff due to an extended leaching event (18-hour leach test) for <br />13 mine-wastes sampled. <br />Table 4 shows a ranking of the mine-wastes according to NAP results for all the mine-wastes <br />included in this study. This ranking of results according to NAP is somewhat different than the rankings <br />produced using leachate results. However, there also are some similarities. Four of the top five ranked <br />using NAP are the same as for the 5-minute and 18-hour leaching tests, albeit in slightly different order. <br />The Togo mine-waste ranked first, meaning it required the most CaCO, in order to neutralize the waste. <br />The Santiago mine-waste was second, followed by the Lower Radical mine-waste. NAP Results for all the <br />sites are given in the summaries for individual mine-waste sites and in Appendix 1. <br />Table 4. Mine-waste rankings for NAP (net-acid production). <br />Hageman_SIR_2508.doc 9 7/21/20042:50 PM