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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. The <br />aquifers are monitored at five (5) locations; immediately down-gradient of the well field, up- <br />gradient at two locations, remote down-gradient 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 lean; 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 pH. The A-Groove and B- <br />Groove aquifers are similar in water quality with moderate 'CDs. conductivity. SAR. but high <br />fluoride. However, the B-Groove aquifer generally has sli`.zhtl}' higher levels of TDS. conductivity, <br />SAR and Iuoride. The Dissolution Surface Aquifer is characterized by high TDS. conductivity, <br />SAR. magnesium, potassium, and moderate pH. <br />lhe fbllow-ing graphs represent analytical results from the past five (5) }ears for monitor wells <br />located within and inunediately down-gradient from the well field. Bicarbonate. Sodium, -Dotal <br />Dissolved Solids (TDS) and Conductivitv were selected as the constituents most likely to detect <br />negative impacts from solution mining activities. Except for a few sample specific anomalies, there <br />is little variation in the ana1vtical results. The results from 2009 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 Geld. <br />Figure 5,2 - Well 90-1 is completed in the A-Groove aquifer and provides the raw water supply <br />to the plant. <br />90-1 <br />10000.000 <br />1000.000 ?a?..•e.++??..-??ee.??.?-..oe?.+s• ? Bicarb <br />Sodium <br />100.000 s : e R s f?? t+ <br />E Conductivity <br />10.000 , ' ' X,r #1- 1" <br />-.--Fluoride <br />1.000 - • Sulfate <br />? P °' Series? <br />6G <br />O? O? O? O? O? O? O? O? a TDS <br />tica .?` ar ??a Ica '- tr 41, <br />Date <br />2009 Annual Report 10 of 33