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`• and E pits by causing drawdowns very near the pit edges. The <br />installation of backfill wells GD3 and GF11 have defined the <br />depressed elevations in the backfill areas. The backfill water <br />levels will likely stabilize lower than the pre-mine levels due to <br />the increased permeability of the backfill aquifer which allows the <br />water in the aquifer to be transmitted at a lower gradient. The <br />heads in the northern end of the backfill aquifer will likely <br />recover above the pre-mine level. Table 2-1 of the 1990 Annual <br />Hydrologic report (Hydro-Engineering, 1991) presents aquifer <br />properties at Trapper Mine. The permeabilities from the backfill <br />aquifers are significantly greater than the coal aquifers which <br />they replace. <br />• Additional drawdown east of D pit and near C pit are the main <br />changes in the QR water level map affected by Trapper mining. <br />Small natural water level decreases near wells GP5 and GE1 have <br />slightly affected the contours near these wells. The natural water <br />level decline near well GP1 has also changed contours in this area. <br />The contour elevations north of E pit have decreased since last <br />year, likely due to the impact from previous mining or possibly due <br />to a decrease in recharge. Some rise of the contour elevations <br />north of the D pit could have occurred by the movement of <br />additional water into the QR aquifer in these areas. Gradients and <br />flow directions for the QR aquifer in 1991 are similar to those <br />observed in 1990. <br />Map No. 2-2 presents the water-level elevation contours for <br />the HI aquifer in the Fall of 1991. Wells GB5, GC1, GE2, GF4, GP3, <br />2-15 <br />