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PERMFILE44465
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PERMFILE44465
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Entry Properties
Last modified
8/24/2016 10:46:55 PM
Creation date
11/20/2007 11:56:02 AM
Metadata
Fields
Template:
DRMS Permit Index
Permit No
M1980244
IBM Index Class Name
Permit File
Doc Date
8/15/2002
Doc Name
Draft NPDES Permit
From
CDPHE
To
DMG
Media Type
D
Archive
No
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COLORADO DEPARTMENT OF HEATH, Wnrer' Orm/iry Division <br />Rationale - Pnge 4, Permit No. CO-0043648 <br />Mining -Surface mining occurs in the very upper tenches of the Arequa Gulch within the diatreme. Any precipitation <br />falling on the surface ntirre travels down: into the relatively porous diatreme m:d there is no evidence that this water <br />contributes surface or gromtd water flow to the spring collection system or the underdrnin system. Additionally, surface <br />mining upgradient of the spring collection and trnderdrain systems has lowered the topography of the Main Cresson Pit <br />below the elevation of the nearest portion of these systems. <br />Overburden Storage Area -TheAregun Gulch overburden storage area is downgradient oftheMain Cresson surface mine. <br />The spring collection system was installed below n portion of the Aregua Gulch overburden storage area before <br />development. Aporous gravel layer and geotextile was installed to separate the spring collection system from the material <br />to be placed ir: the Arequa Gulch overburden storage wren including the relocated Carlton Mill tailings. Thefirst bench and <br />slope of the Arequa Gulch overburden storage area was reclaimed in 1997. This reclamation area was directly above a <br />significant portion of the spring collection system. Reclnrnadon of the second lift slope occurred in ]999 rand 2000. The <br />second lift reclamation extends over the upgrndiertt part of the spring collection system. During 2001 grid the first halfof <br />2002, topsoil and vegetation have been removed from the reclaimed lower bench and adjacent slope in preparation for <br />extension of the Phase Na VLF There will be nofurtlter placement ofoverburdert in the Aregua GulcTt overburden storage <br />area that overlays the spring collection system. With the cover of tailing and overburden, meteoric water can no longer ntix <br />directly with the spring seepage. Seepage, if it were to occur front the relocated Carlton Mill tailing may also be collected. <br />Given tl~e high degree ofcornpaction ofthe relntivelyfine trailing, seepngefrorn these tailings is not expected to occur. <br />VLF-The VLFis downgradient ofthe overburden storage area. The YLFis designed, pennitterl, constructed, and operated <br />to isolate leach solution of CC& V's beneficiation operation from the environment, including the spring collection system and <br />underdrains. Isolation is effectuated by using n multi-layer liner (i. e., co»rpacted clay and synthetic materials) system. <br />Frequent monitoring ofvarious systems, including the spring collection system and underdrains, over the pnstseven years of <br />VLF operation confirms the effectiveness of the liner system in achieving solution containment and isolation within the VLF. <br />A rnanitori»g syste»t approved pursuant to C.R.S. 34-32-]01 etseg is employed to ensure proper operation and corrtainrnent <br />of materials in the VLF The VLF was constructed in mt area from which historic mill tailings were removed and residual <br />materials from other past operations were used in the approved construction. Therefore, some trace concentratiau of <br />cymride from historic operations may be measured but these trace concentrations are not indicative ofdischarges from the <br />VLF. The VLF is being expanded pursuant to approved permits from the Mined Land Reclamation Board. Grading, <br />placenrertt, and compaction ofsoil liner fzll, and installation ofsynthettc liner on the frrsr lift bench and slope ofrhe Arequa <br />Gulch overburden storage area were completed in June 2001. The VLF Phase IVa double liner system now overlies the <br />majority of the spring collection system, as shown on Figures 5 and 6. Compacted road surfaces, construction laydown <br />areas, and rock slopes of the Arequa Gulch overburden storage area represent the remainder of the area overlying the <br />spring collection system. <br />The spring collection and underdrnin systems have no comrection to arty active minir:g area by virtue of the facts Zhat there <br />is rro leakagefrorn the VLF, they are hydrologically isolated front the Cresson Pit, and overburden is rro longer beingplaced <br />in the Arequa Gulch Overburden Storage Aren. Therefore, water flowing through these systems is trot, given the <br />Modification Rule, mine drainage. <br />The limitations in the past permit for Outfa11001A that were based on the Pnrt 440 federal effluent limitation guidelines <br />were never in effect as a result of the series of stays set by the Teller County District Court. <br />Given the changes in the operation of the Cresson Project in the area oftheobove-described drainage systems, the policy <br />changes set out in the Modification Rule, and the fact that lirnitntions based on federal effluent lirnitntion guidelines for <br />Outfall001A never took effect, the Division is not including limitations based on federal effluent limitation guidelines in this <br />permit. Storm water discharges from outfalls in the previous permit (OO2A, 003A, 004A) and any other sirnilarstonn water <br />outfalls are covered under the general storm waterpennit re-issued for the Cresson Project on September 21, 2001, acrd the <br />associated storm water management plan provided to the Division and certified by CC&V. <br />G. Outfalls: <br />This penrtit addresses discharges front the following point source discharges, shown on Figure 4 of the permit, that are <br />associated with the Cressart Project. <br />Outfall DOIA - is downgradient ofthe sediment pond that discharges to Arequa Gulch downstream ofthe YLF: Outfa11001A <br />is located upstream ofthe dischargefrom the diversion ditch that intercepts storm water runofffrom areas upgradient ofthe <br />VLF. Outfa11001A is located at CC&V's monitoring paint AG 1.5, which is about 350 feet downstream of the crest of the <br />sedimentation pond darn and is thefirst available location with suitnblefottndation rand channel charncteristicsfor aflow <br />
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