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wells has to be natural. Increases in TDS in 3rd White Sandstone well P-8 were large in <br />1997 and could be due to upgradient mining. Similar natural TDS concentrations have <br />been observed in nearby 2nd White Sandstone well P-5, which indicates that these <br />sandstones naturally contain some higher concentrations. <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. The TDS for well J-1 <br />increased in 1997 but is very similar to concentrations observed in this well historically. The <br />changes in Pyeatt alluvial well P-1 are thought to be natural because they are similar to <br />those observed prior to mining in this drainage. <br />Sulfate concentrations in wells GD-2 and P-5 have been increasing with time. <br />Sulfate concentrations in wells GD-3, GF-7, GE-2, GF-3, GF-11 and GP-4 are generally <br />declining. Increases in wells GC-1 and GC-3 have to be natural due to their locations. A <br />major portion of the increase in well P-5 occurred prior to mining in this area. Sulfate <br />increases in wells GD-3 and GF-11 are very likely due to mining while the remainder of the <br />increases could be from natural variation, mining or a 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 />6-4 <br />