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<br /> <br />There is some variability in trace metal concentrations at the discharge <br />point but it is not sufficient to account for the high concentrations measured <br />at the Long Lake headgate. <br />C. Radiochemical Analysis <br />For the purpose of this test, grab samples were taken some of which <br />did exceed the 10 pci/1 limitation fora grab sample, although the monthly <br />composite did not exceed the applicable permit limitation. This would account <br />for the high levels reported at the Long Lake headgate. It was also noted <br />gross-alpha activity of the effluent was higher than expected for the dissolved <br />uranium present. <br />Both problems were found to be caused by the -400 mesh fine~> from the <br />ore sorter washwater. <br />• D. Ore Sorter Washwater <br />It was determined that the water treatment plant was not removing the <br />-400 mesh fines from the effluent. <br />The washwater circuit was redesigned to recycle the wash water using a <br />drum filter to remove the -400 mesh fines. {See Section 3.1) Since the time <br />when this design change was implemented, tests of the pond effluent show the <br />total uranium has been reduced by 82% and the suspended Radium -226 by 99%. <br />(See Table 5, Ore Sorter Wash Water Tracer Study, October 18, 1978 prepared by <br />Hazen Reserach, Inc.) <br />E. Physiochemical Reactions between Waste Dump and Rain <br />The approximate volume of the waste dump at the present time is 230,000 <br />• <br />tons. The annual increase is estimated to be at a rate of 60,000 tons. The <br />nominal design ratio of ore sorter reject and mine development rock in the <br />,' <br />2-11 <br />