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U <br />~~ <br />edges. The installation of backfill welts GD-3 and GF-I 1 has defined the depressed elevations in the <br />backfill areas. The wells in this azea experienced fairly steady levels during 2005. The water level <br />increases in 2005 are likely due to more rechazge this last yeaz. The backfill water levels will likely <br />stabilize lower than the pre-mine levels due to the increased permeability of the backfill aquifer, <br />which allows the water in the aquifer to be transmitted at a lower gradient. The gradient calculated <br />for the backfill near D pit is less than 0.00I ft/ft, compared to the undisturbed gradient of 0.12 ft/ft <br />near well GP-6. The heads in the northem end of the backfill aquifer will likely recover above the <br />pre-mine level. Backfill springs aze not expected to develop neaz 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 aze <br />significantly greater than the coal aquifers that they replace. <br />The water-level contours extend through the pit azeas 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 azeas of the QR aquifer and aze indicated by the <br />contours. <br />The QR water-level map at Trapper Mine was very similaz in 2005 to the 2004 water- <br />level elevations. Gradients and flow directions for the QR aquifer in 2005 are similaz to those <br />observed in 2004. <br />Map No. 2-2 presents the water-level elevation contours for the HI aquifer in the Fall of <br />L_~ <br />2005. 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-7 <br />are completed in the backfill in the azea where the H and I coal seams were mined. Flow direction in <br />Trapper Mining Company 2-9 <br />2005 Annual Report <br />