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Environmental Protection Plan, Schwartzwalder Mine 11-2 <br />• <br />The discharge permit limits shown in Table 11-1 applied to the single discharge point (Outfall 001), the <br />pipe at which water from the treated water retention pond was released to Ralston Creek. In the 29 <br />reporting periods leading up to the discharge permit renewal in 2005, CDPHE identified only four limit <br />excursions: pH (1 event), thallium (1 event), silver (1 event), and ceriodaphnia WET test results (1 event). <br />The Discharge Monitoring Reports for this outfall reported no discharge after the water treatment plant was <br />shut down in June 2002. <br />The discharge permit limits shown in Table 11-1 were Water Quality Based Effluent Limits (WQBELs) <br />which were calculated based on EPA effluent limits for mine drainage. The following table lists the EPA <br />effluent limitations for mine drainage from open-pit and underground uranium mines as listed in <br />40 CFR 440.32 and used in the calculation of WQBELs. <br />U.S. EPA Effluent Limitations for Mine Drainage from Open-Pit and Underground Uranium <br />Mines (40 CFR 440.32] <br />Maximum for any one day 30 day average <br />Ra-226 (dissolved) 10 pCi/l (0.37 Bq/1) 3 pCi/1(0.111 <br />. B..qn) ......................................... <br />Ra-226......total ....................................... <br />...... ..... 30 pCi/1...(1.._ _.1....Bq/1)........................_.....10 pCi/l (0.37._Bq/1)..... <br />............................................(....................)............. ...... .............. ............ .............. ......... ............................................ <br /> ......... ......................................................................................................... <br />U 4 mg/l 2 mg/1 <br />• Water treatment resumed in July, 2010, at a new discharge point (Outfall 001A) located approximately 85 <br />feet east of Sump 1 (about 1,600 feet downstream of former Outfall 001). The nominal 100-gpm system is <br />permitted to treat up to 200 gpm (0.288 MGD) and began operation on July 30, 2010. The discharge <br />permit renewal, including proposed changes to the outfall location, monitoring frequency, and effluent <br />limits (Table 11-2) is currently undergoing review and public comment prior to being finalized by CDPHE <br />WQCD. <br />• <br />4109C.100731 Whetstone Associates 6