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be found in previous AI-IRs. Tables 12a through 17a provide the historical statistical summaries of collected data <br />• at wells 001-83-106, 001-83-107, 95M001, FBR-2-E, 97012TC and 97013TC, respectively through 2003. <br />Tables 12b through 17b provide historical water level summaries for each site through 2003. Figures ] 8 through <br />25 provide graphical representations of water levels and selected water quality parameters recorded at active sites. <br />The pumping of well 001-83-106 (Figure 18) complicates the potentiometric surface in the Trout Creek <br />Sandstone. Water levels in well 001-83-106 continue a slight increase, as seen during the previous four water <br />years. The potentiometric surface vends prevalent in the Twentymile Sandstone and Wadge Overburden aquifers <br />are not evident in the monitored Trout Creek wells. The previously monitored well 006-83-48C routinely <br />exhibited water levels in the 7100 ft elevation range while replacement well FCM#2 exhibited levels around the <br />6520 ft elevation during 1995. In the fall of 1995, well 95M001 was established in pan to address the apparent <br />discrepancy in water levels between wells 006-83-48C and FCM#2. Water levels from well 95M001 confirm <br />that levels recorded from well FCM #2 were accurate (Figure 20). Mining in the northern mining district began in <br />1995, which is down dip of this well. V1'ater levels in well 95M001 continue to decline since the 1999 water <br />year, which appears to be influenced by the mining operation. <br />Significant inflows from the Trout Creek Sandstone into the mine workings have not been encountered to date to <br />account for the apparent lowering of the potentiometric surface in the Trout Creek formation, as indicated by the <br />water level data previously recorded for well 006-83-48C. Some dewatering of the aquifer does occur from the <br />pumping of well 001-83-]06 to supply the mine with domestic water. <br />The southernmost Trout Creek well, 001-83-107 (Figure 19), water levels appear ro have leveled off after several <br />yeas of continued decline. Located down dip of the TCC facility water well (001-83-106), steady declines in <br />water level since the early 1990 may reflect effects from longwall mining that began in the western mining <br />district in 1990, in addition to water well use (Figure 21). <br />Well FBR-2-E (Figure 22), located along the eastern permit boundary exhibited consistent water levels until early <br />1999, then dropped about 50 feet and immediately stabilized with consistent water levels at the lower depth <br />through 2004. The specific reason for this drop is not apparent, although many historical boreholes and some <br />faulting exists in the general vicinity. Water levels were at the 6665 ft elevation during 2004, which is similar to <br />the previous four water years. TDS values for FBR-2-E (Figure 23) dropped in 2001, but have subsequently <br />rebounded back to historical values. The exact reason for this decline is unknown. <br />We1197013TC (Figure 24) water levels remain consistent with that of the last two years. Water quality values for <br />well 97013TC (Figure 25) appear consistent with historical values. <br />Field measurements are presented in Tables 12 through 17 for Trout Creek Sandstone wells. Field parameter <br />measurements on these wells during 2004 returned values within anticipated ranges with no mine related impacts <br />evident. At We1195M001 (Table 14), conductivity values continue to be high. . <br />• Fish Creek Sandstone: Two Fish Creek Sandstone wells (97M001 and 9]M004) require monitoring on a <br />semiannual basis for water level only. These requirements were met during 2004. An additional well (Ashley) <br />6 <br />