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3.2 SULFATE <br />Figure B-8 presents the sulfate concentrations for QR wells GD -2 and GD -3. Sulfate in <br />backfill well GD -3 were steady between 2000 and 2009 and then overall increased until 2011 with <br />fairly steady values through 2016. The 2017 values indicate a very gradually increasing trend. This <br />indicates that the sulfate fluctuations in the backfill aquifer may be larger than the native QR aquifer. <br />Future monitoring of this well will define whether sulfate concentrations will increase in the backfill <br />aquifer when water levels rise to a higher level in the backfill material. Concentrations in well GD -2 <br />had overall gradually increased for several years but declined in 2006 and 2007 prior to an overall <br />larger increase in 2008 through 2017. The recent sulfate concentrations in well GD -2 indicate the <br />QR aquifer near well GD -2 may have started to be affected by the upgradient backfill aquifer water <br />quality. <br />Figure B-9 also presents sulfate concentrations for additional QR wells. This figure shows <br />that sulfate concentrations in backfill well GF -11, which is upgradient of QR well GF -6, were <br />decreasing in 2006 and 2007, and overall steady in 2008 through 2017 showing a decline from the <br />historic peak in 2001. Future monitoring is needed to define the maximum sulfate concentration in <br />this backfill aquifer which may have been defined in 2001 and 2002. The sulfate concentrations <br />gradually increased in well GF -6, downgradient of well GF -11 until becoming steady the last five <br />years. Sulfate concentrations for the last few years had also overall gradually increased in QR well <br />GP -5 until becoming fairly steady the last few years. The sulfate in well GLEV-1 is very small. <br />Figure B-10 presents the sulfate concentrations for KLM aquifer wells GP -2, GP -4 and GP - <br />8. Sulfate concentrations in eastern well GP -2 have varied significantly but were similar in 2012 and <br />2017 to historic values. These changes are within the natural historic range defined at this well prior <br />to mining in this area. Overall steady sulfate concentrations in well GP -4 have existed the last few <br />Trapper Mining Company 3-5 <br />2017 Annual Report <br />