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• 6 and backfill wells GD-3 and GF-11. The ground-water flow in the QR aquifer is mainly to <br /> the north. Mining has only affected the QR aquifer close to the D, E and F pits by causing <br /> drawdowns very near the pit edges. The installation of backfill wells GD-3 and GF-11 has <br /> defined the depressed elevations in the backfill areas. The wells in this area experienced a <br /> gradual decline or steady levels during 1999. These steady levels or declines are likely due <br /> to less recharge during 1999. The backfill water levels will likely stabilize lower than the <br /> pre-mine levels due to the increased permeability of the backfill aquifer, which allows the <br /> water in the aquifer to be transmitted at a lower gradient. The gradient calculated for the <br /> backfill near D pit is 0.07 ft/ft, compared to the undisturbed gradient of 0.14 ft/ft near well <br /> GP-i. The heads in the northern end of the backfill aquifer will likely recover above the <br /> pre-mine level. Backfill springs are not expected to develop near the northern end of the <br /> • QR backfill because backfill water levels would have to recover greater than 100 feet. <br /> Table 2-1 of the 1990 Annual Hydrologic Report (Hydro-Engineering, 1991) presents <br /> aquifer properties at Trapper Mine. The permeabilities from the backfill aquifers are <br /> significantly greater than the coal aquifers that they replace. <br /> The QR water-level map at Trapper Mine was very similar in 1999 to the 1998 <br /> water-level elevations. Gradients and flow directions for the QR aquifer in 1999 are similar <br /> to those observed in 1998. <br /> Map No. 2-2 presents the water-level elevation contours for the HI aquifer in the <br /> Fall of 1999. Wells GB-5, GC-1, GE-2, GF-4, GP-3, GP-7, and GMP-1, which are completed <br /> in the HI aquifer, and backfill wells GF-5 and GF-7, were used in the development of this <br /> map. Wells GF-5 and GF-7 are completed in the backfill in the area where the H and I coal <br /> • seams were mined. Flow direction in the HI aquifer has been changed mainly near the A <br /> 2-9 <br />