2008-03-14_REPORT - C1981010 (5)

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3.0 GROUND-WATER QUALITY A ndix B resents the ound-water uali data for the Tra er Mine. This ndix pI~ P ~' q tY PP ~I~ tabulates all of the historical data in Table B-1 and presents TDS and sulfate plots versus time to convey changes in the major constituent water quality. Appendix B also presens the spring and seep water-quality data. Water quality for the springs and seeps are included in this section because their source is ground water. Section 3.7 presents a discussion of the spring and seep water-quality data. 3.1 TOTAL DISSOLVED SOLIDS (TDS) Figures B-1 through B-7 present plots of the TDS concentrations for the Trapper Mine wells. The wells have been grouped together based on aquifers. Figure B-1 presents the TDS concentrations versus time for two QR aquifer wells GD-2 and - 1 GD-3 is a backfill well in the R uifer. TDS concentrations have been fairly steady GD 3. We 1 Q aq for the last nine years in well GD-3. The fluctuation in this bacldll aquifer is well within natural ranges and may be very similar to variations that would have occurred in the QR aquifer at this location. Some of the TDS in the backfill aquifer may be due to leaching from the backfill material. The TDS in this backfill aquifer is greater than it is downgradient in the R Coal at GD-2 which overall slightly decreased in 2007 but has been fairly steady for several years. Figure B-2 also presents a group of three QR wells. Well GF-11 is an equivalent QR aquifer well in the backfill. The 2007 TDS concentrations overall decreased in backfill well GF-11 and is still below its peak in 2001 and 2002. Concentrations in the QR aquifer are monitored downgradient at well GF-6 and have shown no influence from the upgradient mining, except for a very slight overall increasing trend. These small changes are well within natural variations. Figure Trapper Mining Company 3-1 2007 Annual Report