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• by the configuration of the top of clay and zones or channels of increased <br />permeability. Hydraulic conductivities are estimated to be 3 gallons/day/ftZ in <br />these zones. Ground-water conditions would be considered unconfined. <br />However, locally confined conditions may exist in the less weathered portions of <br />overburden clays and silts. Instantaneous discharge rates estimated for the entire <br />length of an excavated face are between 1 to 10 gpm, with maximum total <br />accumulated discharge rates of less than 5 gpm (excavated face =pit length = <br />2700 ft.). <br />The lower portion of the coal seam (bottom 2 ft.) occasionally discharges small <br />amounts of ground water into the coal void just after mining. Ground water <br />production rates from an excavated coal face 60 ft. by 8 ft. have not exceeded 1 <br />gpm. Occurrence of water in the coal seam appears to be somewhat restricted to <br />structural depressions of the coal seam. Ground-water production rates do not <br />increase significantly as mining approaches the western boundary of Ennis Draw. <br />This suggests that the coal seam has very low permeability (hydraulic conductivity <br />estimated to be .23 or 23 gpd/ft2 - 29 gpd/ftZ, McWhorter) and/or the coal seam <br />does not have lateral continuity to the fluvial deposits of Ennis Draw. Since the <br />coal is considered to be a confined aquifer, and is not fully saturated, it would be <br />reasonable to conclude that the coal seam does not have hydraulic conductivity <br />with the Ennis Draw subsurface water system and associated stream deposits. <br />• Please refer to the following cross-sectional views depicting geohydrological <br />conditions existing in the second five year permit area. These cross-sections show <br />the relationships between the second 5 year extension area and other ground-water <br />systems in the area. No surface water features exist in the area (for additional <br />information, refer to 2.06.8). <br /> <br />52 <br />