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increase in sulfate concentrations occurred in eastern QR well GP-1 in 1996. An increase <br />in TDS did not occur in this well in the same sample which questions the validity of this <br />increase. <br />Figure B-13 presents the sulfate concentrations for KLM aquifer wells GA-2, GF-3, <br />GP-2, GP-4 and GP-8. Fairly steady sulfate concentrations for the last few years have <br />been shown in well GF-3. Sulfate concentrations in eastern wells GP-2 and GP-8 vary <br />significantly but should be natural due to their location in the eastem portion of the Trapper <br />permit area. A significant decline in sulfate concentration has occurred over the last few <br />years in well GP-4. Some decline in TDS has been observed in this well during this period <br />of time but at a much smaller amount than sulfate. <br />Sulfate concentrations for the HI aquifer wells are presented in Figures B-14 and <br />B-15. The sulfate concentration in wells in the HI aquifer wells in Figure B-14 are fairly • <br />similar except for the values in backfill well GF-7, which are substantially greater than those <br />in downgradient well GF-4. Avery gradual increase in sulfate concentration in <br />downgradient well GF-4 has been observed over the last few years. This increase is well <br />within the natural variation of sulfate concentrations in the HI aquifer but could be due to <br />the effects of the backfill aquifer upgradient. Sulfate concentrations in backfill well GF-7 <br />significantly decreased in the last portion of 1995 and 1996. An overall declining rate has <br />been observed since a peak in 1993 of sulfate concentrations in well GF-7. Sulfate <br />concentrations in well GMP-1 have been gradually increasing with time, with the exception <br />of a few outliers. The two latest concentrations in 1996 are substantially higher and indicate <br />a much larger increase in sulfate concentrations in well GMP-1. Well GMP-1 is <br />downgradient of the HI mining and, therefore, some effect on the sulfate concentrations on • <br />3-6 <br />