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• stabilize lower than the re-mine levels due to the <br /> likely t p <br /> increased permeability of the backfill aquifer which allows the <br /> water in the aquifer to be transmitted at a lower gradient. Table <br /> 2-1 ( page 2-18) presents present aquifer properties at Trapper <br /> Mine. The permeabilities from the backfill aquifers are presently <br /> significantly greater than the coal aquifers which they replace. <br /> Drawdowns in the OR aquifer in the far western portion of <br /> Trapper permit near well GEI are much more extensive than adjacent <br /> to the remainder of Trapper Mine. These larger drawdowns are not <br /> thought to be caused by Trapper dewatering . Some rise of the <br /> contour elevations north of D and E pits could have occurred by <br /> the movement of additional water into the OR aquifer in these <br /> • areas. Gradients and flow directions in the OR aquifer for 1989 <br /> are similar to those observed in 1988. <br /> Map No. 2-2 presents the water-level elevation contours for <br /> the HI aquifer for the Fall of 1989. Wells GB5, GC1 , GE2, GF4, <br /> GP3 and GP7 which are completed in the HI aquifer, and backfill <br /> wells GF5 and GF7, were used in the development of this map. <br /> Wells GF5 and GF7 are completed in the backfill in the area where <br /> the H and I coal seams were mined. Flow in the HI aquifer has <br /> been changed mainly at the A, B, C, D and E pits. The overall flow <br /> regime in this aquifer is close to that observed in 1988 (see <br /> Hydro-Engineering, 1989) . The ground-water gradient between the <br /> backfill aquifer and the unmined HI aquifer downgradient is <br /> relatively flat as it is in the OR backfill . <br /> 2-15 <br />