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levels to recover to pre -mine levels in the reclaimed pits except near the northern (down -dip) end of <br />the mined area, where levels may be limited by the elevation of backfill springs from the northern <br />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 sixteen years <br />at a slightly lower level. The TDS values in well GF -11 may have reached its peak in 2001, <br />currently values are much lower than its peak and have been relatively steady from 2006 through <br />2016 with a very gradual increasing trend. It is likely that the TDS will remain higher for many <br />years before returning to pre -mine concentrations in these two wells. The change in major <br />constituent concentration in water in these two wells will likely decrease during wet cycles and <br />gradually decline as readily soluble constituents are removed. The water quality in QR wells GD -2 <br />and GF -6 has been only slightly affected by the upgradient mining. The remainder of the QR wells <br />are located away from present mining activities and likely not affected. <br />Trapper Mining Company 6-3 <br />2016 Annual Report <br />