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concentrations have been observed in well GP -7. Sulfate concentrations in eastern HI aquifer well <br />GC -1 have been similar to the previous higher values in well GMP -1 and had to be natural until the <br />last few years. The sulfate concentration in well GLEV-3 are similar to those in well GMP -1 but <br />have to be natural due to the ground -water flow direction at this well. Therefore, a upper limit for <br />sulfate concentration that is greater than 600 mg/l may be needed to indicate that the increases may <br />be due to the mining operation. The 2016 value from well GC -1 was similar to past values but <br />significantly less than the value to the east from well GLEV-3. <br />Figure B-13 presents the sulfate concentrations for three 3rd White Sandstone wells. The <br />previous eleven years of sulfate values from well P-8 had overall gradually decreased while overall <br />the last seven years have slightly increased. The magnitude and timing of the prior increase in sulfate <br />concentrations in well P-8 indicate that this is due to mining. The sulfate changes in wells GC -2 and <br />GP -9 are within the natural range of concentrations for this aquifer. Figure B-13 presents the sulfate <br />concentrations for well P-5. Well P-5 contained only a small amount of water for a sample in 2014. <br />The prior sulfate concentrations in well P-5 were natural and show that the 2014 relatively high value <br />could be natural for this sandstone. <br />Figure B-14 presents the sulfate concentrations for alluvial wells GC -3, P-1, P-3, J-1 and <br />COY. The sulfate concentrations in alluvial well P-1 have been variable with recent values slightly <br />higher than historical natural values for this well. The 2016 sulfate concentration for Johnson Gulch <br />well J-1 gradually increased in 2016 with recent values being slightly higher than the natural levels in <br />the Flume Gulch alluvium at well COY. Sulfate concentrations in the Flume Gulch wells (GC -3 and <br />COY) have fluctuated from approximately 300 to 1200 mg/l. The natural variability in sulfate <br />concentrations for the surf cial alluvial aquifers in this area would be expected to be large and the <br />full range of historical natural values may have not been defined. <br />Trapper Mining Company 3-7 <br />2016 Annual Report <br />