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trends in precipitation which could potentially impact TDS levels in well M -14. Figure 8 shows <br />the annual precipitation recorded at three weather stations in the San Luis Valley. The annual <br />precipitation was higher than normal in the years (2005, 2006, 2007) that preceded an increasing <br />trend in water level, TDS, and calcium concentration levels found in well M -14 (see Figures 9 and <br />LO). Due to the and nature of the San Luis Valley and the amount of additional precipitation <br />received during 2005, 2006, and 2007 Fi re 8 , without a corresponding detectable increase in <br />TDS over the same period (Figure 9 , it is not believed to have had any significant impact on the <br />elevated TDS and calcium values in well M -14. Comparison of Figure 3 and Figure 8 shows a <br />general rise of the water table in well M -14 during the period of increasing precipitation from 2002 <br />to 2007. <br />6.0 LINED TAILING FACILITY (LTF) ASSESSMENT <br />As mentioned earlier, well M -14 is approximately 80 feet west from the toe of the main <br />embankment of the tailing pond and approximately 60 feet south of the LTF collection ditch, as <br />shown in Figure 1. No specific sampling was performed related to the LTF, Collection Ditch, or <br />the Collection Pond under the Response Plan. However, data obtained from routine monitoring <br />of the LTF were reviewed and are summarized below as they relate to the Response Plan. <br />6.1 General LTF Geologic and Hydrogeologic Conditions <br />The soils in the thick unsaturated zone have a moisture content significantly less than the specific <br />retention of the soil. Therefore, the water content in the soils would have to be increased above <br />the specific retention for unsaturated flow to be initiated. Without a significant source of water <br />above these thick unsaturated materials, it is unlikely that any fluids escaping the tailings facility <br />would reach the groundwater table directly beneath the facilities. <br />6.2 Solid Surface Reactions <br />Under typical aquifer conditions, common aquifer minerals have a net negative electrical charge <br />of their surfaces due to unsatisfied chemical bonds at mineral surfaces or constituent substitution <br />within the mineral structure. These negatively charged surfaces tend to attract and hold (sorb) <br />TR -32 M -14 TDS Response Plan Report AES, Inc. <br />Battle Mountain Resources — San Luis, CO 10 January 2015 (Update) <br />