Laserfiche WebLink
indicate that this is due to mining. The sulfate changes in wells GC -2 and GP -9 are within the <br />natural range of concentrations for this aquifer. Figure B -13 presents the sulfate concentrations for <br />well P -5. Well P -5 contained only a small amount of water for a sample in 2011. The prior sulfate <br />concentrations in well P -5 were natural and show that relatively high values naturally exist in this <br />sandstone. <br />Figure B -14 presents the sulfate concentrations for wells GC -3, P -1, P -3, J -1 and COY. The <br />sulfate concentrations in alluvial well P -1 declined in 2006 and 2007 and increased in 2008 and 2009 <br />to a level within historical natural values for this well prior to declining in 2010 and increasing in <br />2011 and 2012. Sulfate concentrations are variable in well P -1. The 2012 sulfate concentration for <br />Johnson Gulch well J -1 was similar to recent higher values and similar to the natural levels in the <br />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/1. <br />33 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 seven years. <br />The upgradient mining in the QR seams has not significantly affected the pH in this area of the <br />Trapper Mining Company 3-7 <br />2012 Annual Report <br />