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COLO21D0 DLP,tPTd'IE:VT OF PUP,IIC HE:fL1•Fl:I:VD ENV1RONil1E:V%' Wcrer Qualiry Contra/ Dntsiun Ranuncle Amendment Nu. 1. Page 7, Penntt Na CO-OOpOZ21 dl Grneral bdnnnauar ~ Tre penuuree should read the acrrre W"ET r•~sting sectio,t irr Parr / ,I 4. of [!te • permit for mfornation applicable to these new discharges T.he permit outlines the tear ~eq«rrer,~en(s and the required follow up ncno+rs the perntrree must rake ro resolve a roxinty ine'ulrrt. Tile permittee should read, along wit( the doaanents listed in Pan L.a -{. a. of the permit, the Colorado LVatcr Orratirv Control Division Biomonimriav Guit(nnce Document doted lulu 1, 1993. This document outlines the criteria used by the Diviston in such areas as grantuf; relief from IVET testing, rnodrfving test methods and c/tanging test species. Tire permittee s/tould be rnvare tlint some of t/te conditions outlined shove may be subjeu to clmn¢e iJthe jnnliN experiences a change ut discharge, as outlined in Part I/ A.Z. of the permit. Suc/t chmtges shall be reported to the Division rmmedrare[y. ~) Erempttian jot Surface Runo~Ort(v - Outfn!! 0I): The di5dtnrges Jrwn outfal[ 015 contain surface runoff solely and do not contain mxtc polltdants ut torn anwunrs. On this basis, 6VET resting is nor a reyairement for this outjall However, the Divisrat rzsen~es the right to reopen the perntit to include WET testing, should facilirv catditions change or ijnew mfornratiort becomes available. 6) Species Chanve For Orttfall 005: 77te permittee requested that, for ourfafl 005, the test species be changed from Ceriodaphnia sp. to Daphnia magna. They strbmi¢ed supporting laboramry data demonstrating that high salinity caused test failures with Cerioda halo while Daphnia magna passed in concurrent tests on nvo instances in July /993. This change is approved. Part I.A. 4. a. of the permit is amended to reflect this change. B. rLlonitoring 1. Effluent Monitorine: Effluent monimring jot the new outfalls will be required as shown in Trbles VI-4 and V!- 5. Refer to the permit for locations of monitoring points. • hlonitarirrp, Frequency Reduction: 77te permittee requested that the rnonitorirtg frequency for all otttfalls except 003 be reduced to monthly for tl:e three parameters jot which weekly monitoring is now required (p H, oil & grease and flow). They asked that the weekly frequenry remain for orrrfall 003 because it receives flow from the shop area and the truck wash and the quatiry may be more variable. Pte other outfalls primarily receive surface runoff from disnrrbed and undisturbed areas. The permittee cites problems accessing remote areas where many of these outfalls are located (even in good weather because there are ao roads), the lack of noncarnpliartce with these field parameters, artd the cost of sampling and analysis as the primary reasons jot this request. The permittee provided data on compliance for existing otttfalls from 1980 through 1998. Outfalls 002, 005, 008. 004, 010 and 011 had no pH excursions daring this period. Otttfatt 004 had six excursions otrt of 727 measurements. The erctrrsions occurred benveen 1984 and 1987 and were attributed to algae. Oittfnll 006 had 8 excursions, all ocatrring in 1990 and 1991. These excursions were also attributed to algae. ivone of the exceedences were attributed to the sources direuly. Only outfall 003, which receives flow from the truck wash system, ltas experienced any oil and grease excursions. This were prior to 1991. Installation ojoil booms prevent future occurrences. None of rite autfalls have ar /tad flow limitations. The Division is applying this reques( to the currently au(horized outfnlls. 77ie permittee will install remote monitoring equrpmenr for flow and pFf at the new outfalls 012 througA 017. This will enable them to firlfi![ the weekly monitoring requirement. However, it still would be difficult for them to access these s«es at a weekly basis to make usual oil and grease observanons. So, dtey will install and maintain oil booms ar these ourfalls~ On this basis, the od and grease monitoring frequenry will be changed to monthly. Tire flow to these ponds is primarily surface nmoff franc disnvbed and rmdisturbed areas. The Colorado Dtvinon oj,Llinerals and Geology (CDh1G) specialist assigned ro this mine cample,r has nrdirated thn; there . should be no Jlow that would cause nit upset resulting in untauol effluent qun(iry. The CD,vIG has no obleuion ro a monitoring jrequenry reduction