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of a few outliers. The 1997 data indicate a decline in concentrations from the 1996 concentrations for well GMP-1. Well GMP-1 is downgradient of the HI mining and, therefore, some effect on the sulfate concentrations on the HI aquifer at this location is possible. The 1997 concentration in well GP-3 increased after a gradual decline in sulfate concentrations over the previous few years. Sulfate concentrations in eastern HI aquifer well GC-1 have been greater than those in well GMP-1 and are natural. Therefore, a sulfate concentration of at least greater than 600 mg/I is needed to be confident that the increases are due to the mining operation. Figure B-16 presents the sulfate concentrations for five 3`d White Sandstone wells. A gradual declining trend in 3rd White Sandstone well GB-2 has been occurring over the last few years. The latest value in well 81-03A is similar to sulfate concentrations in the • 3`d White Sandstone wells. The last two values in well P-8 show a significant increase in sulfate concentration. Sulfate concentrations in well P-8 are presently similar to the natural levels that have been observed for numerous years in 2nd White Sandstone well P-5. The higher natural concentrations in well P-5 makes it difficult to determine whether the present increases in well P-8 are due to the effects of mining. Figure B-17 presents the sulfate concentrations for wells GE-3, GLUX-1 and P-5. The sulfate concentrations for both GE-3 and GLUX-1 have remained low, while the sulfate concentrations in well P-5 have stayed high. Figure B-18 presents the sulfate concentrations for wells GC-3, P-1, P-3, J-1 and COY. The sulfate concentrations in alluvial well P-1 have stayed in the 600 to 1200 mgll range, while the sulfate concentration in the Lewis Shale near this well has been • consistently higher. The 1995 and 1997 sulfate concentrations for Johnson Gulch well J-1 3-7