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• A short segment of Fish Creek crosses approximately 160 feet into the zone of anticipated subsidence (based on <br />the subsidence limit line) along the extreme eastem edge of the 19-Right Longwall Panel. Minimal subsidence <br />impacts were anticipated along roughly 500 linear feet of Fish Creek, in this area. Note that during 2006, no <br />significant ponding effects were observed in this area. Hydrologic monitoring in 2006 did not indicate significant <br />water quality impacts to Fish Creek. Iron concentrations for surface sites SW-14, SW-15, and 305 ranged from <br />350 ug/1 to 1300 ug/I. Note that seasonal fluctuations in the concentrations of some analytical parameters (e.g. <br />iron, conductivity, TDS, etc.) do occur at the surface sites. Increases in iron concentration are often related to <br />accumulation and leaching of iron-bearing strata/sediments during spring mnoff. Some elevated iron <br />concentrations may also be related to ponding effects (e.g. increased solids in ponded samples) <br />Foidel Creek: was historically undermined and subsided by TCC's mining of the 9 Rt, 8 Rt, 7 Rt, and to a very <br />limited extent, the 6 Rt panel, and extreme eastem end of panel 12 Rt. Mining in 12 Rt was completed in 2001, <br />and subsequently sealed in September 2001. No significant changes to the creek channel were noted in 2006. <br />Middle Creek: was historically undermined and subsided by TCC's mining of the 2 through 6 RT. No ponds <br />were formed over the mined out panels. Mining in 6 RT was completed in 2000. No significant changes to the <br />creek channel were noted in 2006. <br />5.0 SUMMARY AND CONCLUSIONS <br />• Overall, no significant hydrology impacts, attributable to activities at the Foidel Creek Mine, were noted during <br />2006. See discussion below, summarizing data assessments. <br />Water Wells: Water levels monitored in the Twentymile Wadge Overburden wells wells remained stable and <br />comparable to previously collected data, and no significant water quality influences were evident from data <br />obtained during 2006. <br />Similatily, Twenrymile Sandstone wells remained stable and comparable to previously collected data, and no <br />significant water quality influences were evident from data obtained during 2006. Localized dewatering of the <br />Trout Creek Sandstone appears evident in the vicinity of the TCC potable water well 001-83-106 (Figure 18), <br />although the level stabilized in 2000, and continues to be stable through 2006. The historical declining water <br />level trend at well 001-83-107 (Figure 19), continued in 2006. This decline may be attributable to the pumping of <br />well 001-83-106. Well monitoring at 95M001 (Figure 20) indicated a continuing decline in water levels which <br />began in 1997, and appears to have stabilized in 2003. No significant inflows from the Trout Creek formation <br />into the mine workings have been encountered to explain this difference in potentiomevic surface or to suggest <br />that dewatering of the formation is directly attributable to mining activities. No readily apparent water quality <br />impacts associated with mining are noted for the Trout Creek Sandstone aquifer based upon data collected during <br />2006. <br />Mining related dewatering impacts were noted for the Fish Creek sandstone wells 91M001 and 91M004 (Figure <br />26), and the Ashley well (Figure 27). Wells 91M001 and 91M004 were undermined in 1995 and exhibited <br />historic water level declines corresponding to mining activity. Water levels in these wells subsequently stabilized, <br />IS <br />