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_ ,~ _ <br />l~la±er Quality <br />• Preliminary research findings by Colorado State University indicate <br />thai: the annual salt pickup rate from mine spoils can vary from 0.23 <br />metric tons per acre per inch in a surface and subsurface runoff regime <br />of 16 inches where approximately 50 percent of the precipitation occurs <br />as snow to approximately 0.79 tons per acre per inch in a surface and <br />subsurface runoff regime of less than 1 inch. These are order-of-magnitude <br />estimates that serve only as indicators of potential impact. <br />Assuming the upper limit (0.79 metric tons ner acre per inch) of salt <br />pickup rate, 3.2 inches of annual runoff, of which O.G inch is surface <br />end 2.8 inches are subsurface flow and deep seepage,/ salt pickup during <br />phase I would be: <br />1.5 acres per year initially disturbed by mine spoils (assumed x <br />0.8 T/acre/inch x 2.8 inches per year (subsurface runoff) = 3.4 T/year. <br />This rou,h estimate can be put in perspective by comparison r•~ith irriyatien <br />return flows in the area (approximately 6 T/acre). On this basis, the <br />anticipated salt pickup from mine spoils is perhaps 1/3 that frem irrigated <br />land. <br />flo problems with toxicity are anticipated from the mine spoils; <br />ho~•iever, careful Chemical monitoring by means of saturated mine spoil <br />analyses will provide data for corrective action to control salt uptake <br />and toxicity should it become necessary during the mining period. <br />~/See hydrologic analysis in ~~hich mining impacts on the water yield <br />of ldestmoreland Canyon are discussed. <br />I-• <br />