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stemmed from waters derived from the KLM interval. An exploration drill hole was established roughly 40 <br />feet west of Spring 99-2. This hole (99-AE23) was drilled to a total depth of 60 feet and was initiated near <br />the base of the Third White Sandstone. During drilling, the flow from spring 99-2 was observed to stop as <br />flow from the exploration drill hole commenced, suggesting the shallow exploration borehole was <br />providing an alternative flow path for the water normally discharged from the spring. Once the exploration <br />hole was sealed, flow from the spring was reestablished. This may indicate that water from Spring 99-2 <br />was derived from a shallow source. Springs 99-2 and 99-3 were both disturbed by mining activities <br />during the fall of 2000. <br />Post-mine Groundwater Qualitv <br />Radian (1981) measured the chemical composition of the Derringer and Enfield Pit overburdens and <br />conducted leach tests to determine the leaching characteristics of these materials.. Radian also <br />conducted batch leaching tests to determine which constituents are likely to be leached from the <br />overburden spoils. The batch tests indicated that manganese, molybdenum and vanadium are species <br />that may potentially leach from overburden at significant concentrations. The batch tests indicated that <br />iron should not significantly leach from the overburden. Concentrations of iron in the post-mine <br />groundwater will probably be significant because the pre-mine conditions are high. Groundwater quality <br />constituent concentrations for some parameters are expected to be higher than pre-mine concentrations <br />for an extended period of time after mining. Sulfate levels in particular can be expected to be higher <br />following mining due to the oxidation of pyrites in the overburden materials. The maximum sulfate <br />concentrations derived from the column leach tests for the weathered and unweathered overburden from <br />the D and E pits varied from 1210 to 2150 mg/I (see Tables 5-4 through 5-7 in Radian, 1981). The higher <br />sulfate levels will be reflected in higher TDS values. The backfill monitoring well maximum sulfate <br />concentrations at Trapper vary, suggesting different water qualities can be anticipated at different <br />locations <br />The spoil water quality, in general, is better than indicated by the Radian leach tests. The TDS and major <br />constituents from the Colt Seep (mined through in 1988) were less than the maximum observed values <br />from the leach tests. Well GF-5 also exhibits better than the average concentrations from the leach tests. <br />Leach tests commonly over-predict the water quality constituent concentrations that are expected. The <br />leach tests indicated that several tenths of a mg/I of manganese should be expected in the spoil water. <br />The leach tests also indicated that several hundredths of a mg/I of molybdenum and vanadium should be <br />in the spoil water, while spoil water tested does not contain a significant amount of molybdenum or <br />vanadium. The leach tests seem to be a fairly good indicator of which constituents will be in the spoil <br />4-238c <br />P00 <br />` l?4?9