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observed in 2006. A steady sulfate concentration was observed in 2006 in well GP -6. As expected, <br />the sulfate concentrations are greater in downgradient well GP -5 and its changes are well within <br />natural variations. <br />Figure B -11 presents the sulfate concentrations for KLM aquifer wells GP -2, GP-4 and GP- <br />8. Sulfate concentrations in eastern well GP -2 have varied significantly but recently have been <br />steady. These changes are within the natural historic range defined at this well prior to mining in <br />this area. Overall steady sulfate concentrations in well GP-4 have existed the last few years and <br />these are less than natural variations observed in this aquifer. Sulfate concentrations in well GP -8 <br />have stayed steady and small as mining approaches this area.. <br />Sulfate concentrations for the HI aquifer wells are presented in Figures B -12 and B -13. The <br />sulfate concentration in wells in the HI aquifer wells in Figure B -12 are fairly similar except for the <br />values in backfill well GF -7, which are substantially greater than those in downgradient well GF-4. <br />A gradual decrease in sulfate concentrations has been observed in well GF-4 after a very gradual <br />increase for several years. These small variations are well within the natural variation of sulfate <br />concentrations in the HI aquifer but could be defining the very small effects of the backfill aquifer <br />upgradient. Sulfate concentrations in backfill well GF -7 overall were steady in 2006. The water <br />levels for the last few years have been fairly similar in well GF -7, indicating that these changes are <br />not due to new backfill being saturated but likely due to variations in recharge. Sulfate <br />concentrations have stayed low and steady in backfill well GF -5. These small changes may be <br />defining the very small effects of upgradient mining but the changes are well within natural ranges. <br />This monitoring indicates that if the HI aquifer has been affected in these wells by upgradient <br />mining, it has been very small. <br />Trapper Mining Company 3-6 <br />2006 Annual Report <br />