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83-03 is the Middle Sandstone monitoring well located furthest <br />• <br /> (more than 1.5 miles) from active underground operations for <br /> Mines 5 and 6. The overall trend from 1984 through 1993 <br /> suggests a similar trend to the other Middle Sandstone wells. <br /> The long term decline could be a pressure response due to the <br /> overall drop in potentiometric levels in the Middle Sandstone <br /> in the vicinity of Mines 5 and 6. Monitoring results through <br /> year 1993 still show no apparent change in the water levels in <br /> the Twentymile Sandstone that could be attributable to mining <br /> activities. Water level plots indicate essentially no change. <br /> Based upon the 1993 piezometric map (Figure 14), the <br /> groundwater gradient in the Middle Sandstone ranges from 130 <br /> feet per mile to the southwest to 50 feet per mile to the <br /> southwest. The drop in potentiometric levels in the Middle <br />• <br /> Sandstone unit above the subsided longwall mine panels in the <br /> F and E coal seams has created a potentiometric gradient to <br /> the south in the vicinity of the longwall panels. A <br /> piezometric contour map of the Twentymile Sandstone is <br /> presented in Figure 15. The map indicates that the gradient is <br /> approximately 220 feet per mile to the northwest and shows <br /> essentially no change from 1991. <br />WATER QUALITY <br />The water quality data for the two Trout Creek Sandstone Wells <br />do not indicate any water quality impacts related to mining. <br />The water quality data for the two Trout Creek Sandstone Wells <br />• are summarized on Table 5 through 8. A plot of field <br />4 <br />