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affected the QR aquifer close to the D, E, F, G, K, L and Z pits by causing drawdowns very near the <br />pit edges. The installation of backfill wells GD -3 and GF -11 has defined the depressed elevations in <br />the backfill areas. The water levels from these wells overall gradually rose during 2016. These <br />water level changes are likely due to seasonal recharge in recent years. The backfill water levels <br />will 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 water -level contours in the northeast corner of the Trapper Mine with the water -level <br />elevation from well GLEV-1 shows that the flow in the QR aquifer turns from the north to the <br />northwest due to the change in the dip of the coal seams in this area. <br />The QR water -level map at Trapper Mine was very similar in 2016 to the 2015 water - <br />level elevations. Gradients and flow directions for the QR aquifer in 2016 are similar to those <br />observed in 2015. <br />Trapper Mining Company 2-10 <br />2016 Annual Report <br />