2008-03-14_REPORT - C1981010 (5)

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alluvial system but was dry in 2007. TDS concentrations in Pyeatt alluvial well P-1 had been overall steady the last few years but declined in late 2007 to its lower histoncal level. These variations are within the historical natural range. The alluvial ground water in Johnson Gulch had shown an increasing trend in TDS since 1996 with the values from the last few years are fairly steady. The recent Johnson Gulch alluvial ground water is still within the natural range for TDS in this aquifer. These TDS values and variations are very similar to the natural values and variations observed in Flume Gulch alluvial well, COY. Flume Gulch has two alluvial monitoring wells, GC-3 and COY. TDS concentrations have been fairly steady in well GC-3 with slightly lower values during 2006 and 2007. The 2007 TDS concentrations in the COY well were similar to recent values. The TDS concentrations in the COY well and historical variations in well P-1 show that the Johnson alluvial TDS concentrations are within natural alluvial concentrations in the alluvial aquifers in this area. 3.2 SULFATE Figure B-8 presents the sulfate concentrations for QR wells GD-2 and GD-3. Sulfate in backfill well GD-3 decreased significantly in 1996 and then increased to a similar peak level by 2000. Sulfate concentrations in well GD-3 have been fairly steady at this peak concentration for the last eight years. This indicates that the sulfate fluctuations in the backfill aquifer may be larger than the native QR aquifer. Future monitoring of this well will define whether sulfate concentrations will decrease in the backfill aquifer during wet cycles and increase to a maximum during a dry cycle. Concentrations in well GD-2 had overall gradually increased the last few years but declined in 2006 and 2007. The sulfate concentrations in well GD-2 show that the QR aquifer near well Trapper Mining Company 3-`1 2007 Annual Report