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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 <br />value 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 but within historical natural <br />values for this well. The 2014 sulfate concentration for Johnson Gulch well J -1 was similar to recent <br />higher values and similar to the natural levels in the Flume Gulch alluvium at well COY. Sulfate <br />concentrations in the Flume Gulch wells (GC -3 and COY) have fluctuated from approximately 300 <br />to 1200 mg/l. <br />3.3 pH <br />Field pH is an important parameter to monitor because some coal spoils have the potential to <br />increase acidity of the ground water, which increases the mobility of most heavy metals. A pH of <br />less than 5 would generally be needed to greatly increase the mobility of most heavy metals. <br />Available pH data is tabulated in Table B -1 of Appendix B. The field pH of water from the <br />GC wells has generally been slightly above 7.0 and has been at similar values since the initiation of <br />disturbance in this area. <br />Field pH from well GD -2 slightly decreased in 2005 and near neutral the last nine years. <br />The upgradient mining in the QR seams has not significantly affected the pH in this area of the <br />aquifer. The pH values from backfill well GD -3 are 6.7 for 2014, which is near the values in the <br />native aquifer at well GD -2. <br />Trapper Mining Company 3 -7 <br />2014 Annual Report <br />