2015-03-18_REPORT - C1982056 (4)

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formation is directly attributable to mining activities. No readily apparent water quality impacts associated with mining are noted for the Trout Creek Sandstone aquifer based upon data collected during 2014. Mining related dewatering impacts were noted for the Fish Creek sandstone wells 91 M001 and 91M004 (Figure 26), and the Ashley well (Figure 27). Wells 91 M001 and 91M004 were undermined in 1995 and exhibited historic water level declines corresponding to mining activity. Water levels in these wells subsequently stabilized, exhibiting only seasonal fluctuations. Two springs (SW -1 and SW -2) are monitored in the same vicinity as 91 MOO 1 and 91M004, although neither of the springs flowed in 2014. The Ashley well was undermined in 1999 and exhibited water level declines corresponding to mining activity. This well appeared to be recovering in 2000, continuing through 2014. No unusual observations are noted with respect to Foidel Creek alluvium groundwater levels. The historical increasing conductivity trend in well 001 -S -5 (Figure 32) stabilized in 2004, and appears to be increasing again through the end of 2014. No unusual observations are noted with respect to Fish Creek alluvium groundwater levels. The general water level decline noted in well 006 -AY -1 (Figure 34) since 1995, appears to continue in 2014. Overall, fluctuations at this well are insignificant. No other notable water level observations are apparent based upon review of the 2014 data. Field conductivity readings at this well appear stable over the last few years. Surface Water: 2014 was a decent snow melt year for Routt County and Colorado. Flows on Foidel Creek, Fish Creek, and Trout Creek were relatively normal in comparison to the 2012 drought. Several stream gage studies were performed throughout 2014. Stream rating curves will be re- evaluated in 2015. Additional installation of flow meters will occur in 2015. Conductivity concentrations at site 301, 69, and 1005 on Trout Creek appeared somewhat elevated during the spring runoff season in April. This may be the result of upgradient spring runoff flushing through the old P & M mine area. Fish exhibited some short term spikes in total recoverable iron in the spring. This may be related to a erosion from a precipitation event or a quick rise in snow melt. No other water quality impacts of concern were evident at any surface water sites monitored during 2014. Spoil Springs: Recorded 2014 spoil spring discharges (site 303 -1) occurred in 2014. The 2012 reclamation at the Fish Creek Tipple, resulted in the loss of two smaller associated springs in the 303 series (303 -2 and 303 -3) . Thus, they did not constitute a significant portion of discharge from the TC mine area with the potential to impact off -site areas. Discharges from sedimentation ponds predominately occurred in conformance with applicable CDPS permit limitations and therefore did not constitute significant impacts to receiving waters. Mine Discharge: Mine water discharge site 109 did not discharge to Foidel in 2014. In 2005, TC began redirecting electro- coagulation treated mine water pumped from the Fish Creek Borehole well, underground locations for dust control. Mine water from the Fish Creek Borehole well (which is treated by electro- coagulation) can also be directed to discharge to Fish Creek via site 115. However there was no discharge from this site in 2014. 18