2014-05-28_REPORT - C1982056 (4)

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this area, with the exception of site AVF -15, which appears to be in a permanently ponded area. Hydrologic monitoring in 2013 did not indicate significant water quality impacts to Fish Creek. Note that seasonal fluctuations in the concentrations of some analytical parameters (e.g. iron, conductivity, TDS, etc.) do occur at the surface sites. Increases in iron concentration are often related to accumulation and leaching of iron- bearing strata/sediments during spring runoff. Some elevated iron concentrations may also be related to ponding effects (e.g. increased solids in ponded samples) In 2011, subsidence did occur from mining on the new Western Mining District, such as along County Road 79. However Fish Creek was not subsided in 2013. Foidel Creek: was historically undermined and subsided by TC's mining of the 9 Rt, 8 Rt, 7 Rt, and to a very limited extent, the 6 Rt panel, and extreme eastern end of panel 12 Rt. Mining in 12 Rt was completed in 2001, and subsequently sealed in September 2001. No significant changes to the creek channel were noted in 2013. Middle Creek. was historically undermined and subsided by TC's mining of the 2 through 6 RT. No ponds were formed over the mined out panels. Mining in 6 RT was completed in 2000. No significant changes to the creek channel were noted in 2013. 5.0 SUMMARY AND CONCLUSIONS No significant hydrology impacts, attributable to activities at the Foidel Creek Mine, were noted during 2013. See discussion below, summarizing data assessments. Water Wells: Water levels monitored in the Twentymile Wadge Overburden wells remained stable and comparable to previously collected data, and no significant water quality influences were evident from data obtained during 2013. Twentymile Sandstone wells remained stable and comparable to previously collected data, and no significant water quality influences were evident from data obtained during 2013. Localized dewatering of the Trout Creek Sandstone appears evident in the vicinity of the TC potable water well 001 -83 -106 (Figure 18), although the level stabilized in 2000, and continues to be stable through 2013. The historical declining water level trend at well 001 -83 -107 (Figure 19), continued in 2013. This decline maybe attributable to the pumping of well 001 -83 -106. Well monitoring at 95M001 (Figure 20) indicated a continuing decline in water levels which began in 1997, and appears to have stabilized in 2003. No significant inflows from the Trout Creek formation into the mine workings have been encountered to explain this difference in water level or to suggest that dewatering of the 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 2013. Mining related dewatering impacts were noted for the Fish Creek sandstone wells 91 MOO 1 and 91M004 (Figure 26), and the Ashley well (Figure 27). Wells 91M001 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 M001 and 91 M004, although neither of the springs flowed in 2013. The Ashley well was undermined in 1999 17