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8. Surface water flow: Surface water flows reported were within historic ranges with <br />the exception of S -1 in April 2011. This site on upper Sanborn Creek was <br />reported at 18.75 cfs, well outside the historic range. OMI should revise the <br />2011 AHR to interpret this value, offer any known explanation for it, and <br />identify whether or not this is a mining related impact. <br />9. Surface water quality: <br />a. Significant increases in TSS, Mn, chloride (CI), phosphate (PO4), <br />nitrate /nitrite (NO3 /NO2), sulfate (SO4), and Fe (both total recoverable and <br />dissolved) were seen at most of the surface water sites in April. Under <br />Rule 4.05.13(4)(c), OMI should revise the 2011 AHR to interpret these <br />values and identify whether or not this is a mining related impact. <br />b. HCO3 is markedly decreased at several surface water sites (H -1, E -1, E -2, <br />C -1, NF -3, and NF -1) in 2011. Under Rule 4.05.13(4)(c), OMI should <br />revise the 2011 AHR to interpret these values and identify whether or <br />not this is a mining related impact. <br />10. OMI did not report whether any NPDES /CDPS effluent limit was exceeded in <br />2012, and I did not review DMRs for the 2011 water year. If you have not <br />reviewed the DMRs and need me to do so, let me know. <br />11. Monitoring results are generally in line with the predicted impacts to the <br />hydrologic balance loosely described in Section 2.05 of the permit application <br />package, including "changes in surface water chemistry ", "increases in the levels <br />of TDS, TSS, and certain individual chemical constituents" in surface water, <br />"drainage of seeps /springs ", and "increases in concentrations of TDS and certain <br />individual chemical constituents" in groundwater. Nonetheless, OMI needs to <br />revise the 2011 AHR to include a discussion, under Rule 4.05.13(4)(c) of <br />how the monitoring results to date compare with the predicted impacts to <br />the hydrologic balance presented in the permit application package. <br />12. Field pH and conductivity and laboratory analyzed pH and conductivity are fairly <br />inconsistent at some sites (S -1, C -1, NF -1, HN -1), indicating that the meters used <br />in the field were not properly calibrated. OMI should ensure that meters are <br />properly calibrated prior to future sampling events, and that meters are <br />calculated for the anticipated pH and conductivity levels at each site. <br />