HYDRO25332 - Laserfiche WebLink

Home Browse Search

.., COt.ORabO DEPARThIF.NT OF' NF..ITfl. {enter {judlrry Cwnro! Dirtsion - ~ ~ - - - Rntlonrtle • Page 3, Permit No. CO-00J36J3 ~ ~ - Carlton eLlill tailing material), the ncth•e VLF, residual Carlton tLlilf tailing material in Areryua Grdch. mrd suhgrarle nutterial «rrderlvirrg the VLF tvhic•h incktdes detoxified Ira+clarl urilirrg trratrrial. The following deseriptiorr ofthe mirreJrraures is provirted to srrppurt [he discussion oJ'the applicahilit}+ of ELGs to discharge Outfirll OOIA. '. Summa >-Miuirrganrlmiui«g-relatedactivities,bvCC&VoccurintheheadwatersojArequnGulch. Surfacemirringoccurs ire the jar tipper reaches nfArequa Gulch. OverGurderr materials have bcrrr stored i» n•/rat is referred to as dye "Arequcr Gulch orrrbrrrderr storage area (OSAI "a short distcurce dorvnbradientfrom the rnirring olmratiorts. Slightly doq•rrgradietrt of dris point the Y'LF hac hero ennctructed Floris in Areryria Gulch historically were associated with a spring svstenr that u•as dte srrrJiu•e espressiwr ufrlur/lu~rgrounl water ire the colhn•itun. The less pernreaHlegrarrodinrite in the arenfturetioiu•d ac a pln'sical harrier responsible for the surface erpresslon of !hr shallow grotrrtd realer dint is now collected h}• the spring collection system. fVater eapnrred ht' tJre spring collection s}•stem is separated from and corn•c~t•ed wtrler the VLF to a !otter portiwr ofrtrequrr Gulch x•here dris x•ater rrnrrld )ratork•ally haveJluerd. An underdrain s} stem also ryas constructed ruulcr the VLF tW can•et• shallow gmuad inter tlmt xvne/d also have h(storicallp flowed to the loner reaches o~Ar•eguu Gulch. Wiring Co!(ectiorr St`stenr -The spring collection system catsis[s uja series nfprrforated pipes that werelnid in lrunrralk• u•rt rrreax ideutilicrl duringcarstr'tic•non br the npperArequu Gtdclr area..'!s nwerl above, the springs are «sur/ircr eepre~~siux nj slrallWw ground renter in the atlluriunr near dye geologic crnrtrret rrillr the granudiorirr. The prrfrrrnled pipes connect yr u salirl rcaUed fiuu•-inch diameter pipe drat mends unrlerrteath the 6'LF taut enuvges ar d:e• don ngr«dh'r.t .rule n;`7he t'Ll-~ Phase 11 tae hernr, ac shown au Figure J q~the penrr0. Z%nderdrains - The Phctsr• I prinraty- ru«lerdr«iu ectendc from the Plnnr 11 toe berm {tern der upper reaches riFAr•equa C.ulrlr where the oId Surtc• fliglnra}• b7•Jill slope rx«sses upper Arerlun Gulch. rrs slrox•n on FiLntre 5. The Please 1 prirnrrn' underdrrrirr is a ?4-inch tlirrrnetcr rorrugaurl perfi>raterl polretlr} Terre pipe.cnrrnrrrrderl br rock fill that r«rrges from ?!I fi•r! to /11t1•(cet in x~kldr r«rd neo to five frM in thir•krress. At !e[rel sit-{etches. oJ:ce%ct stnrctur«!/i11. gentrrlile, mtd 80-rail very lotc- drusiq polvedn•lcur ("VLUPE') liner corer thrprinrrrn'turderdrairtftll. Extertsimr ojthr Plurs'e l i'a double lirrrr.rystrnr in ?00? hoc entirely corered the Plrace I prinurn`ruulerdrain. Secourlart• unrlerdruins exJrirdJi•onr the prbnun• rmrlerdruirr inm w1rn1 mere ideruified ac "tree areas "during cotrsrruction activities erred are• a nrnrimunr of"Jiurr feet rridr meet ne•W feet deep. '1•he Phase! securuhu,v u«derdrairr ercavatious arefilled rridrgr~nndar uuurrird less thou 1? inches iir si_r Were! corrre•d wuh at lrnst sts itrrlus ofselectstructnru/fill, gcotertUe, and SO-Weil YI-DPE liner. 7hr sec•««drrp• uadrrrh•ain.c, jriin the ra k•1i11 u/ - ~ the prinrnn• urulerdrabr. i1 sinrilur rlcsigu eras rrserljor the Phase 11 prim«n• aid seconrlan• underdraiiis. All «fdre Phusc 1 am! II ruulerrh-abrs ore henenth the G'1.1•' multi-lgrer liner system. The watershed even poterrti«!Iv corru•ihtrttug m rhe• trrnlerdr•ainc camintrully' rlecrrctses as t/re VLF advmu-rs rrpgrrul(enf ire the Phase 111 and Phrrse• !G' areas. As a res'rdL the cordigru•«tintr aJ'rlre unrlerrtrains c•hartges rrecnrrlinglt•. The Phase Ill nerd Phase IV wrrler<hxtlrrc cousicrWl excat•rued trruc/nts JiI1rr1 n•idr grantrhu-materiu! wrapped ire geotertile. T/rese• rrertrbes rrutgrfiom dfrveTeri wJA•e feet in rridrh mul ni•o-feet to tlu'rc• fret in thickness. lucrrtions o17he ea-istirrgPhnse l/! and plamre°rl Plrare IV uudrrdraGrs are shrnrrr ore Fignrc• ?. TTu• urirlerrh•ahrs Heluir the VL Fhayc berry isol«tedjrnur the•leachirrg sultrtion a)narirrcd nir/rirr the VI.F tesing a nudtidett'cr liner srsten+. At t/reYhacc ll tnr hernr. »•here the mrderdrrtin system t«trlcrlr•hrg the Y'LFerits the Ste7enr, t/rere Ls a rnn.ctrrrc•red ?- Jeet deep, /Otl feet aide c lutrurel, filler! n•ith broken ruck li. e.. « "Frrire•!t rlruiu'%, 1r/tirh strr•rounds tlrefr)llnrvbrgpilxs, rrhicJt are listed in order, gnirrg jram IcJt to right when !Woking rq)slrecnn rnu~drds tJre fixx of the toe hernr: - «) One perf<nnted 14-inch pipe, whic•Jt r•allects grrxrml waterJlnx•ing undernenr/r t/re rrestcvu portion of the VLF ("Wattle «nderrtrain', j. b) One 24-inc•1r solid-ri~alled pipe which has been pernranrrtil}• sc«lyd «t the upper enl, but r+•hich xas arigiually plruvied to carty'stonn x•aterJlousJrorn der Aregua Gulch OSA after theleac•hirrg operation xrrs cnnrpletrd. h has hreu renun•cd «t the upper end clue to site actirities arrd is no longer treerled due to fiutrre routing of •s'fonn u'rrrer ire diversion churuu•Ls. c) Oue 4-inch solid-nulled pipe, which carrks the flore from the Historic Arequa Gtrlc•Ir spring. d) Orte perforated 29-inch pipe, which collects ground water flou•ireg undrnreath the a«steru portion of tlu• VLF ("south unrlcrrlrahr'7. The carrstnrcted rock chemnel srrrrnruuling these pipes also crrrrics Inca/ groan! n•atrr flomirtg rmderneath the VLF. rL/inin~ - Surfitce mitring ne•c•trrs in the ven~ upper renc•lres ojrheArerpru Gulch rridrin the diatreme..duy prertpitatiarr filling on the smjaee mitre trarcls loin into the relatively porous ditrtremc mnl there Ls no cwirlarc•e dart this rratvr caurihutcs surface or groruril water Jlrirr to the spring collection system or der mtdcrdratn .ryxten+. Ar/dtliarrtllr. sorfitce• ntir+in~ «pgradien of the spring cnllec•tinn rind ruulerrh•uin sssterrts has lWrrercr/ the topngraph}' «f7he .lfaitt Cresson Pir helurr the elevation of the nearest portion Wjthesr srstrn+s. Orerhurtlen Stnrrtg_.4rea - The Arcgtru Grdch orerhrrrde« s7nr«gc' aria is' dosyrrgrndient nfthe Alain Crecsnrt surhrce n+i+rr.