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alluvium in this area is reflecting upstream alluvial water containing high levels of TDS, possibly <br />from an old abandoned underground mine up the Little Trout Creek drainage. This conclusion is <br />based partially on the similarity of the water quality between TR-1.5 and WR-1. The location of <br />the underground mine is shown on 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 phenomenon <br />was caused by infiltration of snowmelt water leaching various minerals within the unsaturated <br />zone of reclaimed spoil. As the enriched flow was released over the course of the summer, the <br />conductivity values lessened to that of the stagnant saturated zone. The mounded aquifer <br />exhibits a more diluted state each spring with a return to steady-state as the summer progresses. <br />Specific conductivity and TDS concentrations exhibited the same trends in 2009 as found during <br />previous years of monitoring. Well TR-1.5 was low For both parameters when compared with <br />the past decade. All concentrations were within the historical range. The lowest specific <br />conductivity value in 2009 was recorded at monitoring well TR-3 in September with a reading of <br />680 umhos/cm @ 25 °C and the high was recorded at monitoring well WR-1 in May with a <br />reading of 3950 umhos/cm @ 25 °C. The lowest TEES concentration in 2009 was recorded at <br />monitoring well TR-3 in September with a value of 470 mg/L and the high was recorded at <br />monitoring well WR-1 in May with a value of 4210 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 wells <br />TR-1.5, TR-3, TR-4, WR-1 and TCS-1 for the period of record. Calcium is the major cation <br />found in all of the wells, except TCS-1 which is sodium rich, with concentrations of sodium and <br />magnesium occurring in lesser quantities. The sodium concentration at TR-1.5 in May 2001 was <br />179 ppm. This value is inconsistent with the historical sodium concentrations and the levels after <br />May 2001. Therefore, either sample contamination or laboratory error is suspected. TR-1.5 <br />generally contained the lowest concentrations of cations with a slight increase occurring <br />downstream at TR-3 and TR-4 for the majority of the :record. However, elevated levels of these <br />parameters at TR-1.5 began to occur in 1995 consistent with the elevated specific conductivity <br />and TDS levels previously mentioned. Elevated levels of sodium concentration occurred at TR-4 <br />during the 2004 and 2005 sampling period compared with those of the last decade. However, the <br />sodium concentration levels remain within historical levels found in Trout Creek. <br />Calcium, magnesium and sodium concentrations exhibited the same trends in 2009 as found <br />during previous years of monitoring. The lowest calcium concentration in 2009 was recorded at <br />monitoring well TCS-1 in May with a value of 39 mg/]:. and the high was recorded at monitoring <br />well WR-1 in May with a value of 488 mg/L. The lowest magnesium concentration in 2009 was <br />recorded at monitoring well TCS-1 in May with a value of 14.4 mg/L and the high was recorded <br />at monitoring well WR-1 in May with a value of 445 nng/L. The lowest sodium concentration in <br />2009 was recorded at monitoring well TR-3 in May with a value of 12 mg/L and the high was <br />recorded at monitoring well TCS-1 in August with a value of 293 mg/L. <br />^?WWCENGINEERING Page 13