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<br /> 2.2 GROUND WATER-LEVEL ELEVATION <br /> Three piezometric maps were developed to show the water level <br />, .flow patterns for the QR, HI and Third White Sandstone aquifers at <br /> Trapper Mine. Water levels from the Fall of 1990 were used in the <br /> development of these maps. <br /> Map No. 2-1 presents the water-level elevations for the QR <br /> aquifer. The water-level elevation is shown for the QR wells, GA1, <br /> GD2, GE1, GF6, GP1, GP5 and GP6 and backfill wells GD3 and GF11. <br /> The ground-water flow in the QR aquifer is mainly to the north. <br /> Mining has affected the QR aquifer only close to the C, D and E <br /> 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 <br /> the water in the aquifer to be transmitted at a lower gradient. <br /> The heads in the northern end of the backfill aquifer will likely <br /> recover above the pre-mine level. Table 2-1 (page 2-18) presents <br /> aquifer properties at Trapper Mine. The permeabilities from the <br /> backfill aquifers are presently significantly greater than the <br /> coal aquifers which they replace. <br /> Additional drawdown east of the D pit and near the C pit are <br />_~ -.the main,:changes in the QR water level .map caused by. Trapper <br /> mining.. Small water level rises near wells GP5 and GE1 have <br /> slightly affected the contours near these wells. The nai.ural water <br /> <br /> level decline near well GP1 has also changed contours in this area. <br />2-15 <br />