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• underground operations for Mines 5 and 6. The overall trend from 1984 through 1995 <br />suggests a similar trend to the other Middle Sandstone wells. The long term decline <br />could be a pressure response due to the overall drop in potentiometric levels in the <br />Middle Sandstone in the vicinity of Mines 5 and 6. Except for Well 83-03, the water <br />levels in the Middle Sandstone wells has either recovered or stabilized in 1995. <br />Monitoring results through year 1995 (Fig. 10) still show no apparent change in the <br />water levels in the Twentymile Sandstone that could be attributable to mining <br />activities. Water level plots indicate essentially no change. <br />Based upon the 1995 piezometric map (Figure 11), the groundwater gradient in the <br />• Middle Sandstone ranges from 125 feet per mile to the west northwest to 250 feet per <br />mile to the west southwest. The drop in potentiometric levels in the Middle Sandstone <br />unit above the subsided longwall mine panels in the F and E coal seams has created <br />a potentiometric gradient to the south in the vicinity of the longwall panels. A <br />piezometric contour map of the Twentymile Sandstone is presented in Figure 12. The <br />map indicates that the gradient is approximately 220 feet per mile to the northwest <br />and shows essentially no change from 1991. <br />WATER QUALITY <br />The water quality data for the two Trout Creek Sandstone Wells do not indicate any <br />water quality impacts related to mining. The water quality data for the Trout Creek <br />• <br />C-81-044 1995 AHR Page 4 <br />