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^ Spa i ARdL ~Vi V <br />Specific conductivity (Figure 8) values for the three alluvial wells have <br />' remained fairly constant over the period of record and are consistent with <br />values obtained during the baseline studies. As previously discussed in the <br />' surface water section, data taken between October 1990 and August 1992 is <br />believed to be invalid due to instrument errors. Conductivity values in 1989 <br />and 1990 for the spoils well WR-1 begin with elevated levels caused by the <br />leaching of various elements continuing within the unconsolidated spoils <br />' aquifer as flow passes through. It is believed the lower values recorded <br />during mid-summer to early fall represent a flushing of the dissolved <br />constituents with an increase being experienced as the flow through the spoils <br />' lessens and the in place water stagnates. This seasonal trend is general to <br />all of the major cations and anions. The spring (NPDES discharge point No. <br />' 006) associated with the spoils aquifer would be expected to have similar <br />values as evidenced by comparable TDS concentrations. TDS values (Figure 8) <br />' closely follow the specific conductivity for all the wells, as expected. <br />Calcium/Magnesium/Sodium <br />Calcium is the major cation found in all the wells with concentrations of <br />magnesium and sodium (Figure 9) occurring in lesser quantities. TR-1.5 <br />generally contains the lowest concentrations of cations with a slight increase <br />occurring downstream at TR-3 and TR-4. It is expected that the cyclic nature <br />' of these parameters beginning to develop in 1989 will continue in the future <br />with a buildup in concentrations occurring during the fall and winter months <br />with a flushing action occurring during the spring and summer. The sodium <br />' level for wR-1 of 454 mg/1 obtained during October, 1991, is believed to be an <br />analytical error as levels measured prior to and after the sample data <br />. followed expected trends. <br />Bi _a bona /G >>fa <br />Bicarbonate and sulfate (Figure 10) are beginning to show a trend of <br />topological change similar to that observed in the surface waters. Upstream <br />(TR-1.5) of the spoils spring, bicarbonate is the major anion with sulfate <br />concentrations increasing rapidly along the mine area. This increase may be <br />l6 <br />