2013-03-14_REPORT - C1981010 (7)

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values in well GMP -1 are likely caused by the upgradient mining. A gradual rise in the backfill water level in this area had occurred the last several years. The overall TDS concentrations in well GC -1 in 2012 are similar to values that existed prior to the small increase in 2010. The 2006 through 2009 monitoring indicates the 2005 increases were not representative of large portions of the aquifer in this area. TDS concentrations in HI aquifer well GP -3, further downgradient of well GMP -1, have overall been steady for the period of observation. TDS concentrations in eastern wells have varied, showing that TDS varies naturally over a large range in this aquifer. Fluctuations observed in wells GC -1 and GP -7 except for the last few years must be natural due to their location. Figure B-6 presents the IDS for 3rd White Sandstone wells GC -2, GP -9 and P -8. Concentrations in each of these wells have been fairly steady for the last few years. The TDS for the previous fifteen years for well P -8 shows fairly steady concentrations after a large increase in 1995 over three years to a value of approximately 4000 mg/l. The 2012 TDS concentrations in well P -8 were steady. The increase in well P -8 is above the levels expected for the 3rd White Sandstone and is likely due to the upgradient mining based on the timing and magnitude of the increase. However, some of this higher level could be natural based on natural large concentrations observed in 2nd White Sandstone well P -5. Concentrations are expected to decline in the future if the increase is due to upgradient mining. Figure B-6 also presents TDS values for 2nd White Sandstone well P -5 and shows that the concentration were in the 2500 to 3000 mg/I range prior to mining in this area and were similar to these values in 2011. Natural water - quality concentrations in the 1st, 2nd and 3rd White Sandstones are expected to vary over a similar range. Trapper Mining Company 3 -3 2012 Annual Report