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• 6.0 OBSERVED IlVIPACTS ON THE HYDROLOGIC SYSTEMS OF THE TRAPPER MINE 6.1 GROUND WATER Water-level changes in the last few years for the QR aquifer are mainly due to natural variations in the recharge rate. Water-level changes were observed in QR aquifer wells GD-2 and GF-6, along with associated backfill wells GD-3 and GF-11. Wells GD-2 and GF-6 are fairly close to mined areas but overall steady water levels were observed in these four wells in 2005 except for an increase in the last measurement in well GD-2. The level should be used with caution until it is conned. The responses in these wells indicated that the present water level gradually increased due to the increase in precipitation in 2005. These wells are located near the downgradient toes of D and E pits and/or at the interface of upgradient backfill and the downgradient native QR aquifer. These well locations seem to be relating to changes in precipitation with very little lag in time. Upgradient mining can cause water-level rises in wells downgradient of the mining by allowing ground water to flow to the downgradient end of mine quicker. The backfill aquifers aze generally more permeable than the native aquifer which also allows ground water to flow faster through the backfill material resulting in more water in the aquifer at this location. The input of additional water to the native aquifer at the north end (tce) of the mine has decreased the effects mine dewatering has had on water levels in this portion of the aquifer. Water levels in wells GD-2, GD-3, GF-6 and GF-11 are thought to be at or above the baseline levels for this reason. The slightly higher water levels in well GD-2 in 1998 than those observed in 1986 after six wet years indicates the post-mine levels under the same conditions may be higher. Springs are not expected to develop at the north end of the D and F pits. Trapper Mining Company 6-1 2005 Annual Report