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Figure B-11 presents the sulfate concentrations for KLM aquifer wells GP-2, GP-4 and GP-8. Sulfate concentrations in eastern well GP-2 have varied significantly but recently had gradually increased with the 2005 value being fairly steady. These changes aze within the natural historic range defined at this well prior to mining in this area. Overall steady sulfate concentrations in well GP-4 have existed the last few yeazs and these aze less than natural variations observed in this aquifer. Sulfate concentrations in well GP-8 have stayed steady and small as mining approaches this area. Sulfate concentrations for the HI aquifer wells aze presented in Figures B-12 and B-13. The sulfate concentration in wells in the HI aquifer wells in Figure B-12 are fairly similaz except for the values in backfill well GF-7, which aze substantially greater than those in downgradient well GF-4. Steady sulfate concentrations have been observed in well GF-4 after a very gradual increase for several years. These small variations aze well within the natural variation of sulfate concentrations in • the HI aquifer but could be defining the very small effects of the backfill aquifer upgradient. Sulfate concentrations in backfill well GF-7 overall decreased in 2005 after an overall increase in the last few years. The water levels for the last few years have been fairly similaz in well GF-7, indicating that these changes aze not due to new backlill being saturated but likely due to variations in rechazge. Sulfate concentrations have stayed low and steady in backfill well GF-5. Concentrations in HI well GE-2 had gradually decreased the last few years but were steady for the last two yeazs. This small change may be defining the very small effects of upgradient mining but the changes aze well within natural ranges. This monitoring indicates that if the HI aquifer has been affected in these wells by upgradient mining, it has been very small. Trapper Mining Company 3-6 2005 Annual Report u