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COLORADO DEPARTMEM OF PUBLIC HEALTH AND THE ENVIRONMENT, Water Quality Comrol Division <br />Rationale -Page 17, Permit No. CO-0045225 <br />Therefore, using the best available information, it is reasonable to conclude that rising the 10-yr124-hr <br />runoff volume for the pond release flow, and tl:e average upstream flow in Cripple Creek for dilution, <br />should provide a significant margin ojsajety for protection of water quality standards rhrougltou( the entire <br />spectrum of pond regenerative release and dilution flows shat are likely to exist. <br />4. TMDL Results <br />The following table presents the results of the TMDL for Cripple Creek. The parameters for which a TMDL was <br />done are shown. <br />D. Discussion of Technology Based Effluent Limitations <br />1. Fede fjluent Guidelines and Standards: New Source Performance Standards found under 40 CFR Pan <br />440. subpart !. titled Copper. Lead. Zinc. Gold. Silver and Mo{ybdenum Ores Subcateeorv are shown in <br />the following table: <br />Table VI-5 -Federal EJJlaent Limitations <br />:Parameter ....:: .:: . .•. .::.: 30 Day Avg Cogceruratian Daily;ilfax: Conceidra[ion <br />TSS, mg/f 20 30 <br />Cadmium, mg/1 0.05 0. /0 <br />Copper, mg/! 0.15 0.30 <br />Lead, mg/! 0.3 0.6 <br />Mercury, mg/! 0.001 0.002 <br />Zinc, mg/! 0.75 1.5 <br />pH, su 6.0-9.0, unless the pH ojthe natural receiving wafers, ijunaltered by <br />human activities, would be less than 6.0. In no case shall a pH <br />limitation of less than 5.0 be permitted. <br />While neither overflow nor regenerative releases from poims 002A, 003A, or 004A are "process water" <br />discharges, ar defined in the Division's WQ Policy 17, "Definition of Process Water and Stormwater at <br />Non-Coal Mining Sites ", the above ELG's are listed for the purposes of comparison against the release <br />concentrations discussed above. <br />This rationale and accompanying permit serve as a (oral maximum daily load (TMDL) under Section 303 (d} of <br />the Clean Water Act and will 6e submitted to the USEPA Region V/1I for review and approval. <br />