2017-03-16_REPORT - C1981012 - Laserfiche WebLink

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Water quality data for the downstream surface water point (PRS4) was compared to surface water quality regulations (Reg. 32). As with the historical data, the comparison was made for parameters in the current monitoring plan (Table 28 in the PAP). The relevant parameters and the Reg. 32 standards are as follows: • pH-6.5to 9.0 • Chloride — 250 mg/l (chronic) • Sulfate — 250 mg/l • Iron (total recoverable) — 1.0 mg/l • Iron (dissolved) — 0.3 mg/l • Manganese (dissolved) — 0.05 mg/l. One exceedance of these standards was found in the 2014 data for PRS -4: the recorded concentration for total recoverable iron, 1.025 mg/1, was slightly over the standard of 1.0 mg/1. However, at the upstream point (PRS -1, Table B-1), the total recoverable iron concentration (1.09 mg/1) was approximately equal to this downstream concentration. Furthermore, high total recoverable iron does not appear to be a general pattern at this site, based on data for previous years that are mostly well below the standard. Analysis of Alluvial Groundwater Data Fluctuations in depth to alluvial water do not appear to indicate a significant impact from mining, per the historical data in the 2014 AHR. This assertion is based on data for PAW -1 (upgradient alluvial well) and PAW -9 (downgradient alluvial well). This trend continued with the 2014 data. Water quality data for the downgradient alluvial well (PAW -9) was compared to groundwater regulations (Reg. 41). As with the historical data, the comparison was made for parameters in the current monitoring plan (Table 28 in the PAP). The relevant parameters and the Reg. 41 standards are as follows: • pH-6.5to 8.5 • Chloride (dissolved) — 250 mg/l • Sulfate (dissolved) — 250 mg/l • Iron (dissolved) — 0.3 mg/1 • Manganese (dissolved) — 0.05 mg/l. No exceedances were found for any of these parameters in the 2014 data for PAW -9. Review of New Elk Mine AHRs Page 4