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aquifer, which allows the water in the aquifer to be transmitted at a lower gradient. The gradient <br />calculated for the backfill near D pit is less than 0.07 ft/ft, compared to the undisturbed gradient of <br />0.12 ft/ft near well GP -6. The heads in the northern end of the backfill aquifer will likely recover <br />above the 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 a few tens of feet to <br />reach the lower land surface elevations. Table 2 -1 of the 1990 Annual Hydrologic Report (Hydro - <br />Engineering, 1991) presents aquifer properties at Trapper Mine. The permeabilities from the <br />backfill aquifers are significantly greater than the coal aquifers that they replace. <br />The water -level contours extend through the pit areas for the F, G and Z pits because the <br />R seam was not mined in these pits and therefore the QR aquifer still exist under these pit floors. <br />Some drawdown would be expected in these areas of the QR aquifer and are indicated by the <br />contours. <br />The QR water -level map at Trapper Mine was very similar in 2006 to the 2005 water - <br />level elevations except for the water level decline near wells GD -2 and GD -3 and some additional <br />decline in the F and Z pit areas. Gradients and flow directions for the QR aquifer in 2006 are <br />similar to those observed in 2005. <br />Map No. 2 -2 presents the water -level elevation contours for the HI aquifer in the Fall of <br />2006. Wells GC -1, GE -2, GF-4, GP -3, GP -7, and GMP -1, which are completed in the HI aquifer, <br />and backfill wells GF -5 and GF -7, were used in the development of this map. Wells GF -5 and GF- <br />7 are completed in the backfill in the area where the H and I coal seams were mined. Flow <br />direction in the HI aquifer has been changed mainly near the A pit near well GF-4. The overall <br />flow regime in this aquifer is northerly, similar to that observed in 2005 (see Hydro - Engineering, <br />2006). The ground -water gradient between the backfill aquifer and the un -mined HI aquifer <br />downgradient is relatively flat as it is in the QR backfill. The contours in the HI aquifer have also <br />Trapper Mining Company 2 -9 <br />2006 Annual Report <br />