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• Of the four 25 foot angered holes completed by the USGS, the water level in No. 3 on Taylor Creek declined below the bottom on the hole in the early fall when a tributary stopped flowing, and the others showed only small water level tuctuations. The rest of the holes in bedrock showed normal water level fluctuations. Examination of the water level data indicate that some bedrock wells in the stream valleys penetrate aquifers under pressure. The wells that had not been removed by mining and could still be located were remeasured by LRC WE in 1979. The water levels in these wells had not changed significantly. In four of the W. R. Grace & Co. core holes, Nos. 27, 33, 35 and 45, water at depths of less than 100 feet was cascading from perched aquifers. In Grace core holes Nos. 33 and 35 there was no accumulation of water to depths of 280 feet and 500 feet respectively.. Similarly, in Grace No. 27 water was cascading from a depth of about 80 feet, and measurements were stable only near the plugback depth of 295 feet. This and other well data indicate that groundwater is draining from the dissected upper part of the Williams Fork Formation and that there is not a single, continuous groundwater system on the property above the elevation of Goodspring Creek. Test drilling on the mine site revealed that the limited amounts of groundwater that exist on the site are usually perched on the highest impermeable bed. Continued operation in the active pit during the permit term between 1981 and present has supported the conclusion that little water exists in the sedimentary sequence and that where water is encountered it is limited both vertically and laterally and under perched conditions. In addition, the excavation has been dry in the lower seams where the sandstones show a greater lateral continuity and would be expected to • contain more water in storage than the upper seams. ~ I 2.04.7-6