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Seneca 11 Mine <br />SL -6 Phase Ill Bond Release Request <br />June 2014 <br />in Table 5. No sites exceeded the sulfide standard (0.002 mg /1) in the past three years. The <br />analytical method detects both dissolved sulfides and acid - soluble metallic sulfides present in <br />suspended matter. It is suspected that a large portion of the any sulfides detected is of the latter <br />type, which would bias the un- ionized results high. Any dissolved sulfides present in surface <br />water should eventually oxidize to sulfates. <br />The aquatic life ammonia standard is dependent on pH and temperature. The detection limit for <br />ammonia is 0.05 mg /1. All values above detection limit are compared to table standards, page 87 <br />at this website: htW: / / -,vww.epa.gov /waterscience /criteria /ammonia /99ul2datg.pdf. No sites <br />exceeded the ammonia standard in the past three years. <br />The drinking water standard for mercury is 2 ug /1. The aquatic life standard for mercury is 0.01 <br />ug /1, which is set to protect the average human consumer of fish. The Seneca II Mine contracted <br />lab uses a method with a detection limit of 0.2 ug /1. None of the stream samples collected in the <br />past three years were above the detection limit. During the last NPDES permit renewal, the <br />CDPHE performed a reasonable potential analysis on Outfall 008 (NPDES8). It determined that <br />there was no reasonable potential for this outfall to exceed the mercury limit; therefore, mercury <br />monitoring is no longer required at this outfall. <br />Table 6 Attachment E provides a statistical summary of the water quality for the past three years <br />(2011 to 2013) collected at Spoil Spring 9 (SSSPG9), which is located upstream of and flows into <br />Pond 008 (NPDES8). Table 7 provides a comparison of those data with the CWQCC surface <br />water agricultural standards, Table 8 (both in Attachment E). Comparisons of water quality data <br />collected at SSSPG9 were compared to the agricultural standards because the post - mining land <br />uses of the reclaimed parcel in this Phase III bond release application as designated in the Seneca <br />II Mine's Permit Application Package for the State Mining Permit are livestock grazing and <br />wildlife habitat. Table 7 is of the same format previously discussed above for Table 5. Only one <br />of the CWQCC surface water agricultural use standards was exceeded. The manganese standard <br />was exceeded once with a value of 0.262 mg /1. However, as indicated in the recently revised <br />CWQCC Regulation 31, the standard of 0.2 mg /l applies to plants grown in acidic ( <6.0 pH) <br />29 <br />