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COLORADO DEPARTMENT OF I~ALTH, Water Quality Control Division <br />Rationale, Amendment No. 1 Page 2 Permit No. CO-0027154 <br />I/I. RECE/VING STREAM: <br />A. Identj/-tcation, Classjficatian oral Standards <br />1. Idenrification: The facility discharges go to Foide! Creek, Fith GY~eek, and Middle <br />Creek These receiving waters, including 7}out Creek, are within segmem 13b of <br />the Yampa River subbasin, Upper Colorado River basin. <br />2. ClassiRcation: Segment 13b is classed jor the following uses: Recreation, Class <br />1; Aquatic Life, Class 1 (Co(d); Agriculture. <br />3. Numeric Standards.• The applicable standards jor segment 13b which have been <br />assigned in accordance with the above class fkations can 6e found in 3.3.0 <br />Class fuations and Numeric Standards for the Upper Colorado River Basin (5 CCR <br />1002-8). Refer to the previous renewal rationale for further dircussions regarding <br />the applicable water quality standards. <br />/v. PURPOSE OF AMENDMENT.• <br />This amendmem is 6ting made to: 1J change the compliance point jor collection of grab <br />samples for outfall 005 from the flume to the end of the discharge culvert; and 2J include an <br />additional wastewater source, mint drainage inter, to outfall 007. <br />V. D/SCUSSION OF AMENDMENT.• <br />In a letter dated April 12, 1993 from Marcus Middleton of Cyprus Yampa Valley Coal <br />Corporation (CYVCCJ, the perrtittee requested that the twn above changes for outfalis 005 <br />and 007 be modified in this permit. These tin requesu are discussed in more detail <br />following. <br />CYVCC requested that the compliance poim for collection of grab samples be changed to the <br />to the end of the discharge culvert for outfall 005. This will avoid any potential effects from <br />the adjacent small area exetnpuon flow drainage sources upon samples collected at this <br />outfall. The small area exemption waters are drainages from the adjacem rock filter, haul <br />road(s), and embanbrrem areas. The distance that the sampling location will be moved from <br />the flume to the culven is approximately 30 to 40 feet. <br />CYVCC also requested that the permit be amended to allow for the discharge of mine <br />drainage via ourfall 007. Mine drainage is curremly either discharged via outfal[ 005, or is <br />diverted to the spoil aquifer adjacem to outfall 007 and recycled for use underground. This <br />amendment would allow for the routing of overflow containing mine drainage from [he spoils <br />aquifer to outfa11007, along with direct routing of mine discharge to outfal[ 007. <br />Essemially, the only difference between the existing limitations for outfa[Ls 005 and 007 it <br />that limitations exist jor potentially dissolved silver for outfail 005, and monitoring for this <br />parameter is required jor outfa11007. Thrs was based upon previous comments prior to <br />issuance of the renewal permit (refer to pages 25-26 of the renewal rationale, dated February <br />5, 1993). Since the previous monitoring data for silver at autfall 007 has had concentrations <br />much below the silver permit limits for 005 (with most 007 concentrations below or at the <br />minimum detection level used), this permit amendment will continue with monitoring far <br />potentially drssolved silver at outfall 007. Also, since it is likely that the actual <br />