2001-12-11_PERMIT FILE - C1982056A (3)

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COLORADO DEPARTMENT ~F HEALTH, Water Quality Control Division Rationale, Amendment No. 1 Page 2 Permit No. CO-0027154 lH. RECEN/NC STREAM: A. Identification, Classification and Standards 1. /dentification: The facility discharges go to Foidel Creek, Frsh Creek, and Middle Creek These receiving waters, including Trout Creek, are within segment 136 of the Yampa River subbasin, Upper Colorado River basin. 2. Classification: Segment 136 is classed for the following uses: Recreation, Class 1; Aquatic Life, Class 1 (Cold); Agriculture. 3. Numeric Standards: The applicable standards far segment 13b which have been assigned in accordance with the above class fuations can be found in 3.3.0 Clarsiftcations and Numeric Standards for the Upper Colorado River Basin (S CCR 1002-8J. Refer to the previous renewal rationale jor further discussions regarding the applicable water quality standards. IV. PURPOSE OF AMENDMENT: This amendment is being made to: 1) change the compliance point for collection of grab samples for outfall 005 from the flume to the end of the discharge culvert; and 2J include an additional wastewater source, mine drainage water, to outfall 007. . V DISCUSSION OF AMENDMENT: In a lever dated April 12, 1993 from Marcus Middleton of Cyprus Yampa Vallev Coal Corporation (CYVCCJ, nc~ permittee requested that the two above changes for outfalis 005 and 007 be modified in this permit. These two requests are discussed in mare detail following. CYVCC requested that the compliance poim for collection of grab samples be changed to the to the end of the discharge culvert for outfa[l 005. This will avoid any potential effects from the adjacem small area exemption flow drainage sources upon samples collected at this outfa!!. The small area exemption waters are drainages from the adjacem rock, filter, haul road(s), and embankment areas. The distance that the sampling location will be moved from the flume to the culvert is approxitnateIy 30 to 40 feet. CYVCC also requested that the permit be amended to allow for the discharge of mine drainage via outfall 007. Mine drainage is curremly either discharged via ourfail 005, or is diverted to the spoil aquifer adjacem to outfall 007 and recycled jor use underground. 77iis amendment would allow far the routing of overflow containing mine drainage frotn the spoils aquifer ro outfall 007, along with direct routing of mine discharge [o outfall 007. Essentially, the only difference between the existing limitations for outfalls 005 and 007 is that limitations exist for potentially dissolved silver for outfall 005, and monitoring jar this parameter it required for outfall 007. This was based upon previous continents prior ro issuance of the renewal permit (refer to pages 25-26 of the renewal rationale, dated Februarv • S, 1993). Since the previous twnitoring data for silver at outfa[l 007 has had concentrations much below the silver permit limits for 005 (with mast 007 concentrations below or at the minimum detection level used), this permit amendment will cominue with monitoring jor potentially dissoh~ed silver at outfall 007. Also, since it is likely that the actual