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1 <br /> GROUND WATER MONITORING <br /> ' BEDROCK <br /> SANDSTONE AQUIFERS <br /> Three sandstone aquifers are monitored at the site. There are, in <br /> ' ascending order: Trout Creek Sandstone (2 wells) , Middle Sandstone <br /> (6 wells) , and Twentymile Sandstone (3 wells) . The #5 and #6 Mines <br /> are between the Trout Creek Sandstone and the Middle Sandstone. <br /> ' WATER LEVELS <br /> ' The water levels in all three aquifers show a downward trend in <br /> 1989 . The dramatic decline in some of the Middle Sandstone wells <br /> is due to the effects of nearby longwall mining. The overall <br /> ' decline in the Middle Sandstone is probably also due to the <br /> continual downdip movement of the longwall, and due to the below <br /> normal precipitation in 1988 and 1989. The small decline in the <br /> water level in Twentymile Sandstone is probably due to the dry <br /> t conditions. The decline in the water levels in the Trout Creek <br /> wells is probably due to the increased usage of the wells in the <br /> last two years. <br /> ' Based upon the 1989 piezometric map (Figure 14) , the ground water <br /> gradient in the Middle Sandstone ranges from 110 feet per mile to <br /> ' the southwest to 170 feet per mile to the northwest. A piezometric <br /> contour map of the Twentymile Sandstone is presented in Figure 15. <br /> The indicated gradient is 220 feet per mile to the northwest. <br /> ' WATER QUALITY <br /> The water quality data for the sandstone aquifers are summarized <br /> in Tables 5 through 18. Plots of field conductivity are presented <br /> in Figures 16 through 18. The data indicates that the water <br /> ' quality of all three sandstone aquifers is fairly constant over <br /> the whole period of measurement. The tables include all data <br /> collected through 1989. The data does not indicate any significant <br /> trends. <br /> 1 <br /> COAL <br /> ' FLOWS <br /> Plots of the measured discharges for the two #5 Mine discharge <br /> points are presented in figures 19 and 20. The flows are measured <br /> at the discharges by totalizing flow meters on the dewatering sump <br /> pumps. The mean flow rate did not exceed the predicted values of <br /> ' 760 to 890 combined gpm for the #5 Mine. The 1989 average <br /> t -1- <br />