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flow, conductance, temperature, and pH. These data are summarized on Table 4; well locations are shown on Exhibit 1. Except for some high flow (17-25 gpm) observed during clearing of the drill hole, water pro- duction from zones within and below the mine strata was usually less than 5 gpm; conductance was usually more than 1,100 umho/cm; and pH values showed the produced fluids to be slightly basic. Based on core drilling data and a literature review, two separate water- bearing zones exist in the mine vicinity. A dual completion monitoring well was completed in the spring of 1977 to monitor bath of these water- bearing zones. The two horizons to be monitored were the coal and inter- burden sequences at about 200 to 300 feet deep, and a sandy unit thought to be the Twenty Mile Sandstone at about 500 feet. The geophysical logs indicate this sandy zone is from 500 feet to total depth of the hole. These data are shown on Exhibits 5 and 22. The presence of water in the sandy zone is further indicated by the trace of the temp- erature log, which deviates sharply from a fairly normal geothermal gradient at about 510 feet. The target zone prior to drilling was the Twenty Mile Sandstone, the first supposed principal aquifer below the mine zone, and it was assumed this sandy sequence is the Twenty Mile Sandstone. Based upon projections of structural data provided by Bass et. al., (1955) the bottom of the Twenty Mile may be an additional 50 feet to 75 feet deep. 4Jhether or not this well bottoms in the Twenty Mile is unimportant to the monitoring of the hydrogeological consequences of the proposed mining operation. Exhibit 5 indicates that when the hole was standing open the mine strata would not hold water, even though water was present. This indicates that the gradient is vertically downward in the well hole environ- ment. Natural conditions (lacking well perforations) would suggest a down- dip water movement. The chances that mining will alter or impact this lower sand unit are minimal due to the presence of approximately 250 feet of impervious shales and other marine deposits which segregate the sand- stone from the lower-most coal horizon. 41e11 G 2 (see Exhibit 22) wil l provide the data needed to evaluate the substantiate the above statement. 12 s,.,rt:~c.. .. ~, ,... ..._.:.::.r~.:..,ti„' ...di~rLS!v.._ :...,_: ar, .. k a_ .tea , f ~.'-.:.,. .i. .. it