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contact with the Pyeatt alluvium. It demonstrates the same seasonal variations (Figure A- <br />16) as the P-1 well. <br />Water-level elevations for the Johnson Gulch alluvial well J-1 are also presented <br />in Figure A-16. The J-1 water levels have remained fairly steady. <br />2.2 GROUND WATER-LEVEL ELEVATION (PIEZOMETRIC MAP SUMMARY) <br />Hydro-Engineering developed three piezometric maps to show the water level flow <br />patterns for the QR, HI and 3rd White Sandstone aquifers at Trapper Mine. Water levels <br />from the 3rd quarter of 1996 were used to develop these maps. <br />Map No. 2-1 presents the water-level elevations for the QR aquifer. The <br />water-level elevation is presented for the QR wells: GA-1, GD-2, GE-1, GF-6, GP-1, GP-5, <br />• and GP-6 and backfill wells GD-3 and GF-11. The ground-water flow in the QR aquifer is <br />mainly to the north. Mining has only affected the QR aquifer close to the D and E pits by <br />causing drawdowns very near the pit edges. The installation of backfill wells GD-3 and GF- <br />11 have defined the depressed elevations in the backfill areas. The wells in this area have <br />continued to experience water-level increases during 1996. These increases are due to <br />either the mining moving further away from GD-3 or the continued inactivity of E Pit. The <br />backfill water levels will likely stabilize lower than the pre-mine levels due to the increased <br />permeability of the backfill aquifer which allows the water in the aquifer to be transmitted <br />at a lower gradient. The gradient calculated for the backfill near D pit is 0.08 compared to <br />the undisturbed gradient of 0.14 ft/ft near well GP-6. The heads in the northern end of the <br />backfill aquifer will likely recover above the pre-mine level. Table 2-1 of the 1990 Annual <br />• <br />2-9 <br />