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• <br />11 <br />• <br />this year from NPDES and stream sites in those basins. Standards that <br />were exceeded are: <br />Parameter # of Sites / # of Excursions <br />Iron, Total Recoverable (TR) 6/6 <br />Selenium 1/3 <br />Only three of the six iron exceedances were from NPDES sites. All six <br />exceedances occurred in April. They were likely due to high suspended <br />solids values normally observed during snowmelt runoff. This strict <br />aquatic life standard (1.0 mg/1) was exceeded in over half of the <br />premining stream samples. <br />Currently there is a Temporary Modification for the TR iron standard on <br />Grassy, Sage and Dry Creeks based on "existing quality". SCC <br />participated in the Colorado Water Quality Control Commission's December <br />13, 2010 Temporary Modification Rulemaking Hearing. The Commission <br />approved SCC's proposals for ambient-based TR iron standards to Dry <br />Creek (Segment 13d) and Sage Creek (Segment 13e). These standards will <br />become effective on June 30, 2011. Those standards will be: <br />Dry Creek March-April 3.04 mg/l <br />May-February 1.11 mg/l <br />Lower Sage Creek year round 1.00 mg/l <br />Upper Sage Creek year round 1.25 mg/l <br />The break between Upper and Lower Sage Creek is the west border of <br />Section 18, TSN, R87W. SCC's outfalls for the Seneca II-W Mine discharge <br />into Lower Sage Creek. SCC's outfalls for the Yoast Mine discharge into <br />Upper Sage Creek. The exceedances for TR iron noted at the NPDES sites <br />in this AHR would achieve the new approved standards. <br />Three samples from NPDESI7 exceeded the aquatic life chronic selenium <br />standard, 4.6 ug/l, with values of 12.3, 7.3 and 8.9 ug/l. The acute <br />standard, 18.4 ug/1, was not exceeded. <br />The sulfide data presented in Appendix E are the total of both the <br />ionized (S-) and un-ionized (H2S) forms of hydrogen sulfide. The un- <br />21