COLORADO DEPARTMENTOFPUBLICHEALTHANDENV/RONMENT, WaterQualiryControlDivision
<br />Rationale -Page 2, Permit No. CO-003271 S
<br />016 SR Post-mining 2 ponds 0 0
<br />Vol
<br />0.90 MG Sage Gulch
<br />017 SR, MW Active 2 ponds 0.206 0.206 1.10 MG Oak Gulch
<br />018 SR Active 1 pond 0 0 1.21 MG Horse Gulch
<br />019 SR, MW Active 1 pond 0 0 1.39 MG West Flume Gulch
<br />020 SR, MW Active 3 ponds 0 0 7.03 MG Middle Flume Gulch
<br />021 SR, MW Active 1 pond 0 0 1.71 MG East Middle Flume Gulch
<br />D22 SR Active 1 pond NA NA 0.70 MG Deal Gulch
<br />023 SR, MW Active I pond 0 0 0.55 MG East Flume Gulch
<br />014 SR Active 1 pond NA NA 0.25 MG West Horse Gulch
<br />SR means Surface Runoff, MW means Mine Water, SS means Spoils Spring Water, FD means French Drain Water
<br />NA indicates that pond has not yet been constructed, specifications for these ponds are proposed
<br />F. CLRB Permit No.: C-81-010
<br />III. RECEIVING STREAM
<br />An assessment of the stream standards, low flow data, and ambient stream dtita has been performed to determine the assimilative
<br />capacities for Johnson Gulch, No Name Gulch, Far East Buzzard Gulch, Coyote Gulch, Ute Gulch, Middle Pyeatt Gulch, East
<br />Pyeatt Gulch, West Pyean Gulch, Deer Gulch, Grouse Gulch, Sage Gulch, Oak Gulch, Horse Gulch, West Horse Gulch, West
<br />Flume Gulch, Middle Flume Gulch, East Middle Flume Gulch, East Flume Gulch, and Deal Gulch for potential pollutanu of
<br />concern. Thu information is contained in Appendix A to this rationale. The Division's Permits Unit has reviewed the
<br />assimilative capacities to determine the appropriate water quality-based effluent limitations.- The limitations based on the
<br />assessment and other evaluations conducted as part of thu rationale can be found in Tables VI-1, V/-2, and VI-3 of this rationale.
<br />I[' FACILITYDESCRIPTION .
<br />A. Industry Description
<br />1. Tvne oflndustrv: This facility is a large active surface coal mine. The current production rate is approximately 2.0
<br />million tons per year, the maximum production is limited to 2.6 million tons per year. Mining has concluded in some
<br />portions of the site and most areas have been reclaimed. Other areas will be reclaimed in the near future.
<br />2. Sources to the Treatment Plant: Surface runoff water ("SR') is treated in sedimentation ponds. Water pumped from
<br />active mining areas ("mine water" or "MW') may be combined with SR for treatment prior to discharge. Additionally,
<br />French drain water ("FD') under a road is routed to the ponds culminating at outfa11001, however this is a relatively
<br />clean source of water, unaffected by mining activities. Refer to Table77-1 for information regarding which outfalls
<br />discharge SR alone and which discharge in combination with MW or FD.
<br />3. Chemicals Used: The permittee did not specify any chemicals for use in waters that may be discharged. On this basis,
<br />no chemicals are approved under this permit. Prior Yo use of any applicable chemical, the permittee must submit a
<br />request for approval that includes the moss current Material Safety Data Sheet (MSDS) for that chemical. Until
<br />approved, use of any chemical in waters that may be discharged could result in a discharge of pollutanu not authorized
<br />under the permit. Also see Part ILA.I. of the permit.
<br />B. Wastewater Treatment Description
<br />All wastewater continues to be treated in sedimentation ponds. Outfalls 003, 006, and 010 have been removed since the
<br />areas previously served by these outfalls have been fully reclaimed andfinal bond has been released 6y the Colorado
<br />Division of Minerals and Geology. Spoils spring water no longer flows to outfall 001. Active mining has ceased at areas
<br />served by outfalls 001 and 009, although reclamation work has not yet been completed. The previously mined area served by
<br />outfa11002 will be used to dispose ofpower plant fly ash.
<br />Further, reclamation activities have occurred to the point that the Federal Effluent Guideline definition ofpost-mining
<br />applies at outfalls 012, 013, 015, and 016. Other areas may meet this definition later this year, bur none are expected in the
<br />next few months.
<br />Pursuant to the authority ojArticle 9, Title 25, Regulations for the Certification of Water Treatment Plant and Wastewater
<br />Treatment Plant Operators, this facility will require a certified operator.
<br />Last Revised: 9/29/1004
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