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been observed in nearby 2nd White Sandstone well P-5, which indicates that this • <br />sandstone could naturally contain this concentration. <br />_Significant changes in TDS concentrations have been observed in the alluvial <br />wells GC-3, P-1, J-1, and Coy. The changes in the Flume alluvial wells has to be natural,_ <br />while some of the changes in J-1 water could be due to mining_Overall, the TDS fcx J-1 <br />decreased in 1996 and are well within the natural range in alluvial TDS values defined for <br />this site. The changes in Pyeatt alluvial well P-1 are thought to be natural because they are <br />similar to those observed prior to mining in this drainage. <br />Sulfate concentrations in wells GA-1, GC-1, GC-3, GD-2 and P-5 have been <br />increasing with time. Sulfate concentrations in wells GD-3, GE-1, GE-2, GF-3, GF-11 and <br />GP-4 were increasing but declined in 1996. Increases in wells GC-1 and GC-3 have to be <br />natural due to their locations. A major portion of the increase in well P-5 occurred prior to • <br />mining in this area. Sulfate increases in wells GD-3 and GF-11 are very likely due to mining <br />while the remainder of the increases could be from natural variation, mining or a <br />combination of both. <br />The pH values for all of the Trapper wells are within the range of natural values <br />for these aquifers. The pH values for the four backfill wells are within the range observed, <br />in the other aquifers.. <br />The higher SAR values at well GE-2 are caused by a decrease in the calcium and <br />magnesium concentrations not an increase in sodium. The SAR value for well GB-5 is still <br />within the range of values seen since 1986 when SAR's for this well increased due to <br />decreases in calcium and magnesium. This change occurred after mining in these two <br />areas but was abrupt which is not typical of ground-water changes. The high SAR's in wells <br />6-4 <br />