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• OR Aaulfer <br />Five wells; GA1, GE1, GZ3, GD2, and GF6 are used to monitor the OR aquifer. Water level changes <br />for well GA1 are shown on the hydrograph on Figure 4.8-12. The Q and R coal seams are presently <br />being mined less than 2000 feet from this well to the east and less than 4000 feet to the west. Water <br />levels have risen at an average rate of three feet per year during 1986. Water levels are presently ten <br />feet above the pre-mine levels. Increase in recharge to the OR aquifer is the most likely reason for the <br />rise in water level in the last few years. Another possible explanation is the migration of ground water <br />after blasting from the top of the hill to the base of a particular cut. This could cause water levels in an <br />aquifer near the base of backfilled cuts to rise from the influx of additional ground water. <br />Figure 4.8-13 presents the water level elevation data for well GE1. Water levels have risen to nearly <br />8160 FT-MSL through 1986 after being below 6070 FT-MSL for nearly six previous years. Local <br />pumping from an adjacent underground mine and previous C pit pumping are thought to be the cause of <br />the drawdowns observed in this aquifer. The recent rise in water level elevation corresponds to not <br />mining in this area for several years. <br />• Water levels in well GZ3 showed no changes until October 1985 when levels sharply decreased due to <br />local surface mining (see Figure 4.8-12). Well GZ3 has <br />• <br />4-226] PR.-,f <br />?u??? 13198-.