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6.0 OBSERVED IMPACTS ON THE HYDROLOGIC SYSTEMS <br />OF THE TRAPPER MINE <br />6.1 GROUND WATER <br />Water -level changes in the last few years for the QR aquifer had been mainly due to natural <br />increases in the recharge rate but declined some in 2012 and 2013 due to less recharge. Water -level <br />changes were observed in QR aquifer wells GD -2 and GF -6, along with associated backfill wells <br />-GD -3 and GF -11. Water levels in wells GD -2 and GD -3 declined in 2006 and these declines are <br />thought to be siue t9 some sleep cxpluxation dtU ng in bi s_ar_ea. Water_ levels. rose in 2008 and 2009, <br />with some additional overall rise -in 2011 through 2013 in well GD -2. A gradual decline in water <br />level in GD -3 was observed in 2012 and 2013. Additional monitoring with time is needed to <br />determine the significance of the decline in wells GD -2 and GD -3 but presently well GD-2 has not <br />completely recovered from the 2006 drop. Wells GD -2 and GF -6 are fairly close to mined areas, <br />steady water levels in 2013 were observed in well GF -6. The 2012 responses in well GF -11 <br />indicated that water levels declined due to the decrease in precipitation in 2012 with smaller water <br />level changes in 2013 with normal precipitation. These wells are located near the downgradient toe <br />of D and E pits and/or at the interface of upgradient backfill and the downgradient native QR aquifer. <br />These well locations seem to be relating to changes in precipitation with very little lag in time. <br />Upgradient mining can cause water -level rises in wells downgradient of the mining by <br />allowing ground water to flow to the downgradient end of mine quicker. The backfill aquifers are <br />generally more permeable than the native aquifer which also allows ground water to flow faster <br />through the backfill material resulting in more water in the aquifer at this location. The input of <br />additional water to the native aquifer at the north end (toe) of the mine has decreased the effects mine <br />dewatering has had on water levels in this portion of the aquifer. Water levels in wells GF-6 and GF- <br />11 are thought to be at or above the baseline levels for this reason. The slightly higher water levels in <br />Trapper Mining Company 6 -1 <br />2013 Annual Report <br />