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5.1.3 Monitoring Wells <br />Per regulatory requirements, dedicated monitoring wells have been constructed to monitor four <br />water-bearing zones, the Dissolution Surface. B-Groove. A-Groove and Perched aquifers, see <br />Figure 5-1 fir location of monitoring wells. The aquifers are monitored at five (5) locations-. <br />immediately dowel-gradient of the well field, up-gradient at two locations, remote dovoi-gradient <br />and east in panel 2. <br />Baseline data was obtained prior to ground water pumpage from water well (90-1), and from mining <br />activities from 1991 through the present. Within NSI's lease boundaries, there are three aquifers <br />defined by US EPA as underground sources of drinking water: the Perched, A-Groove and B- <br />Groove Aquifers. The Dissolution Surface Aquifer is not designated as an underground source of <br />drinking water. <br />The Perched Aquifer is characteristically low in total dissolved solids (TDS). conductivity, fluoride. <br />SAR (sodium absorption ratio) and moderate to high in sulfate and pi I. The A-Groove and B- <br />Groove aquifers are similar in water quality with moderate TDS, conductivity, SAR, but high <br />fluoride. However. the B-Groove aquifer generally has slightly higher levels of "IDS, conductivity. <br />SAR and fluoride. The Dissolution Surface Aquifer is characterized by high TDS, conductivity. <br />SAR. magnesium, potassium. and moderate pH. <br />The following graphs represent analytical results from the past five (5) years for monitor wells <br />located within and immediately down-gradient from the well field. Bicarbonate, Sodium, Total <br />Dissolved Solids (TDS) wed Conductivity were selected as the Constituents most likely to detect <br />negative impacts from solution mining activities. Except for a few saniple specitic anomalies, there <br />is little variation in the analytical results. The results from 2008 indicate that solution mining is not <br />impacting the Perched. A-Groove or B-Groove aquifers. <br />The following wells are located within the Well field. <br />Figure 5.2 - Well 90-1 is completed in the A-Groove aquifer and provides the raw water supply <br />to the nlant. <br /> 90-1 <br />10000. o00 <br />1000.000 Bicarb <br /> Sodium <br />rn 100.000 + - - - Conductiv+ty <br />E <br />10.000 TDS <br />1.000 - - --- -- - - -- --- <br /> 0 0 0 CO IT o o 0 0 0 g <br /> C? C7 C7 C?J CJ O CJ C7 C1 C7 C7 U' N N <br /> r <br />M h r M C7 CJ <br /> r [7 M M ( N <br /> r f7 <br /> Da to <br />2008 Annual Report 10 of 28