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is a benefit relative to potential yields from the aquifer. The increased permeability will likely not <br />allow water levels to recover to pre -mine levels in the reclaimed pits except near the northern <br />(down -dip) end of the mined area, where levels may be limited by the elevation of backfill springs <br />from the northern pits in this area. <br />Significant drawdown has developed adjacent to the pits but the extent of these drawdowns <br />is very limited due to the small transmissivity in these aquifers. Recovery of the water levels has <br />occurred over a few years as the pits have moved away from an area. Some water levels will likely <br />not recover to their pre-mine levels due to the different flow characteristics developed with the <br />backfill aquifer and the controlling of the maximum head by backfill springs. <br />Variations in natural recharge to the 2nd White Sandstone affect this aquifer greatly. Mining <br />effects on the system have not been detected. <br />The TDS of water in backfill wells GD -3 and GF -5 are somewhat higher but similar to <br />those of the native aquifers in these areas. TDS for GF -5 is approximately 1.5 times the pre-mine <br />value but is within natural variability of this aquifer. TDS values for backfill wells GF -7 and GF -11 <br />are much higher than the naturally observed concentrations. TDS in well GF -7 has shown some <br />decline from the peak values in the early 1990's and has been fairly steady for the last nine years at <br />a slightly lower level. The TDS in well GF -11 is lower and may have reached its peak in 2001. An <br />overall decline in TDS was observed in well GF -11 in 2006. It is likely that the TDS will remain <br />higher for many years before returning to pre -mine concentrations in these two wells. The change <br />in major constituent concentration in water in these two wells will likely decrease during wet cycles <br />and gradually decline as readily soluble constituents are removed. The water quality in QR wells <br />GD -2 and GF -6 has been only slightly affected, if at all, by the upgradient mining. The 2005 TDS <br />Trapper Mining Company 6 -3 <br />2006 Annual Report <br />