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CONCLUSIONS <br />Based on the supplemental testing program undertaken by BMRI, Geochimica reaches <br />the following tecluucal conclusions: <br />1. L.ogg-term rinsing of the tailings by meteoric water (i.e., rain and snow) will lead <br />to low TDS effluents with well-buffered, alkaline pH values. <br />2. Pore waters in the Lower Impoundment are sufficiently consistent in chemistry that <br />there is no reason to suppose that there exists any possibility of unexpected effluent <br />chemistry. Cyanide concentrations are low, and the WAD cyatvde concentration is <br />expected to decline yet further. Most metals and metalloids are present art very low <br />concentrations, and several (i.e., As, Hg, and 5e) were not detected in any of the <br />five new samples. <br />3. The acid-base accounts and the metals leacltability under EPA Ivfethod 1312 are <br />entirely consistent wish data from pre-operational testing attd from testing shallower <br />zones in the Lower Impoundment. The Method 1312 data show that leaching of the <br />tailings will not adversely affect ground water quality. <br />4. There is no basis in geochemical data for considering that the tailings materials are <br />heterogeneous in composition or differ in geochemical characteristics from those <br />expected prior to operations. <br />Gtochimicn, lac. 7 l6 Seprernber, 1996 <br />