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<br /> <br />Requirement <br /> <br />Regulation Require- <br />ment <br />complied <br />with? <br />(yes / no) <br /> <br />Comment <br /> Overall, PHC predictions appear to be accurate, as illustrated <br /> by the following examples. <br /> Per the PHC, TSS values in the surface water runoff are <br /> expected to increase a few years after mining and then decline. <br /> Data for NPDES sites 001 and 002 illustrate this trend. Per the <br /> PHC, elevated TDS levels will be detected in base flows <br /> derived from backfill aquifers, and Johnson Gulch is the only <br /> surface water drainage that definitely shows mining effects on <br /> TDS during base flow conditions. During 2009, relatively <br /> high TDS concentrations were reported for NPDES sites in <br /> several gulches: Johnson, No Name, East Pyeatt, and Flume. <br /> In general, the data reflect the inverse relationship between <br /> TDS and flow. All four of these sites are downgradient of <br /> potential spoil springs from the A Pit and East A Pit. <br /> Per the PHC, post-mine values of pH in surface water runoff <br /> are not expected to be significantly lower or higher than <br /> present or pre-mine levels. Field pH values for all sites in <br /> 2009 were similar to previous data collected. <br /> Per the PHC, during base flow conditions for surface water <br /> runoff, some water quality constituents may exhibit elevated <br />X. Agreement of concentrations in areas where backfilled aquifers contribute to <br />observed surface water flows through soil springs. This condition is not <br />hydrologic CDRMS strongly exhibited by the 2009 data for Total Iron. Where the <br />impacts with regulation Yes concentration approaches the surface water effluent limitation <br /> 2.05.6(3) of 6 mg/L, at NPDES 020 in April 2009, the highest flow <br />PHC projected in value of the year was recorded. The data for Total Iron were <br />permit reviewed as this constituent contains quantitative effluent <br /> limitations in the NPDES permit. <br /> Per the PHC, Trapper does not anticipate recharge to the <br /> shallow aquifer systems to be adversely affected by mining <br /> operations in the Third White Sandstone. Water levels in <br /> wells GC-2, GP-9, and P-8 (used to monitor the Third White <br /> Sandstone) did not rise or fall considerably between 2008 and <br /> 2009. Previous analysis has indicated good recharge with <br /> above average precipitation over the last few years. <br /> Per the PHC, constituent concentrations in backfill aquifers, <br /> namely TDS and sulfate, are expected to be higher than pre- <br /> mining concentrations for an extended period of time after <br /> mining. The data for TDS concentrations in wells in backfill <br /> aquifers have shown apparent impacts from mining. TDS <br /> concentrations in GD-3 and GF-5 are somewhat higher to <br /> those of native aquifers in these areas. TDS values for wells <br /> GF-7 and GF-11 were much higher than the naturally <br /> observed concentrations in the 1990s and 2000s, but have <br /> declined in recent years. These trends have continued in 2009. <br /> Sulfate concentrations exhibited similar trends as TDS for <br /> wells GD-3, GF-7, and GF-11. Sulfate concentrations in well <br /> GF-5 have been fairly steady since the 1980s. <br />Page 6