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returned to more historic levels during the past decade. However, the values have remained <br />elevated. It appears that the alluvium in this area is reflecting upstream alluvial water <br />containing high levels of TDS, possibly from an old abandoned underground mine up the <br />Little Trout Creek drainage. This conclusion is based partially on the similarity of the water <br />quality between TR-1.5 and WR-1. The location of the underground mine is shown on <br />Exhibit 3.1-1 of the permit. <br />Specific conductivity and TDS in Well WR-1 have tended to progress from an elevated state <br />each spring to a lower state in the fall for the majority of the period of record. This <br />phenomenon was caused by infiltration of snowmelt water leaching various minerals within <br />the unsaturated zone of reclaimed spoil. As the enriched flow was released over the course of <br />the summer, the conductivity values lessened to that of the stagnant saturated zone. The <br />mounded aquifer exhibits a more diluted state each spring with a return to steady-state as the <br />summer progresses. <br />Specific conductivity and TDS concentrations exhibited the same trends in 2008 as found <br />during previous years of monitoring. Well WR-1 began low for both parameters when <br />compared with the past decade however recovered to historical values. All concentrations <br />were within the historical range. The lowest specific conductivity value in 2008 was recorded <br />at monitoring well TR-3 in May and October with a reading of 580 umhos/cm @ 25 °C and <br />the high was recorded at monitoring well TR-1.5 in May with a reading of 4430 umhos/cm @ <br />25 T. The lowest TDS concentration in 2008 was recorded at monitoring well TR-3 in July <br />with a value of 180 mg/L and the high was recorded at monitoring well TR-1.5 in September <br />with a value of 4920 mg/L. <br />4.2.4 Ground Water Calcium, Magnesium and Sodium <br />Charts 26, 27 and 28 show calcium, magnesium and sodium concentrations for monitoring <br />wells TR-1.5, TR-3, TR-4, WR-1 and TCS-1 for the period of record. Calcium is the major <br />cation found in all of the wells, except TCS-1 which is sodium rich, with concentrations of <br />sodium and magnesium occurring in lesser quantities. The sodium concentration at TR-1.5 in <br />May 2001 was 179 ppm. This value is inconsistent with the historical sodium concentrations <br />and the levels after May 2001. Therefore, either sample contamination or laboratory error is <br />suspected. TR-1.5 generally contained the lowest concentrations of cations with a slight <br />increase occurring downstream at TR-3 and TR-4 for the majority of the record. However, <br />elevated levels of these parameters at TR-1.5 began to occur in 1995 consistent with the <br />elevated specific conductivity and TDS levels previously mentioned. Elevated levels of <br />sodium concentration occurred at TR-4 during the 2004 and 2005 sampling period compared <br />with those of the last decade. However, the sodium concentration levels remain within <br />historical levels found in Trout Creek. <br />Calcium, magnesium and sodium concentrations exhibited the same trends in 2008 as found <br />during previous years of monitoring. The lowest calcium concentration in 2008 was recorded <br />at monitoring well TCS-1 in October with a value of 24.9 mg/L and the high was recorded at <br />monitoring well TR-1.5 in May with a value of 520 mg/L. The lowest magnesium <br />11