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installation of backfill wells GD -3 and GF -11 has defined the depressed elevations in the backfill <br />areas. The wells in this area experienced some fluctuating water levels during 2012. The water level <br />changes in 2012 are likely due to seasonal recharge in recent years. The backfill water levels will <br />likely stabilize lower than the pre -mine levels due to the increased permeability of the backfill <br />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 0.05 ft/ft, compared to the undisturbed gradient of <br />0.12 ft/ft. The heads in the northern end of the backfill aquifer will likely recover above the pre - <br />mine level. Backfill springs are not expected to develop near the northern end of the QR backfill <br />because backfill water levels would have to recover greater than a few tens of feet to reach the lower <br />land surface elevations. Table 2 -1 of the 1990 Annual Hydrologic Report (Hydro - Engineering, <br />1991) presents aquifer properties at Trapper Mine. The permeabilities from the backfill aquifers are <br />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 2012 to the 2011 water - <br />level elevations. Gradients and flow directions for the QR aquifer in 2012 are similar to those <br />observed in 2011. <br />Map No. 2 -2 presents the water -level elevation contours for the HI aquifer in the fall of <br />2012. Wells GC -1, GF-4, GP -3, GP -7, and GMP -1, which are completed in the HI aquifer, and <br />backfill wells GF -5 and GF -7, were used in the development of this map. Wells GF -5 and GF -7 are <br />completed in the backfill in the area where the H and I coal seams were mined. Flow direction in the <br />HI aquifer has been changed mainly near the A pit near well GF-4. The overall flow regime in this <br />Trapper Mining Company 2 -9 <br />2012 Annual Report <br />