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ENVIRONMENT ENVIRONNEMENT Environment Environnement Deloro Mine Site Rehabilitation TheDeloroMineSite,Deloro,Ontarioislocatedon mainactivityatthesiteuntilthemarketgavewayto theMoiraRiverinHastingsCountyapproximately8 organicpesticidesinthelate1950s. kmeastofMarmora.SituatedwheretheCanadian Delorowasthefirstplantintheworldtoproduce ShieldintersectstheGreatLakesLowlands,thearea cobaltcommercially. isrichinmineraldeposits.Arsenicandothermateri- Delorowasalsoaleadingproducerofstellite,a alshavebeenleachingintotheMoiraRiverandhave cobalt-chromium-tungstenalloywhichwasresistant contaminatedtheMoiraRiverbasin.Arsenicinthe toheat,wear,abrasionandcorrosion;andwhichhad environmentisapotentialhealthhazard. considerablestrategicvalueduringdiewaryears. EnvironmentOntariohasbeenoperatinganarsenic Duringtfielifeoftfiesmeltingoperations,oresfrom treatmentplantatthesitesinceApril1979. allovertiieworld,includingNorthernRhodesia, DelorofromtheSpanishMeloro',"ofgold",grew MoroccoandtheBelgianCongowereprocessedat outofthegoldrushdaysandbecameknov^masthe Deloro. "ValleyofGold".MiningandrefiningattheDeloro Inthe1930s,1940sand1950ssmeltedore,orspeiss, MineSitestartedinthe1860sandcontinueduntil fromEldoradoNudectrLimitedinPortHopewere 1961.Historicalrecordsshowthatgoldwasdiscov- broughttoDeloroforfurtherrefinement.Materials eredatnearbyEldoradoin1866andatDelorosome smeltedandrefinedatDeloroincluded:gold,silver, timepriorto1871.Severalminingoperationsextract- arsenic,cobalt,ruckel,lead,bismuthandcopper. edgold-bearingoreintheearlyyears.By1871 approximately25shallowshaftshadbeensunkatÛ\e ACenturyofWork LeavesHazardousMaterials Delorosite.Thehigharseniccontentofttieoresmade Largequantitiesofrefiningslag,minetailings,labo- therecoveryofgolddifficultandhazardous,buta ratorywastes,arseniccompoundsandarserucalpes- seriesofsignificanttechnicaldevelopmentsinminer- ticidesremainedatthesite.Acenturyofthehandling alprocessingmadeitpossible.Mineexplorationat ofhazardousmaterialsandchemicalshaslefttiiesite withmassivecontaminationproblems.Fuels,chemi- thesitecontinuedandthestillviableGatling,Tuttle andRedshaftsweredeepenedandextended. calsandrawmaterialssuchassulphuricacid,coke, lime,sodaash,causticsoda,liquidchlorine,salt, MinesClosed: SmeltingContinued scrapiron,sodiumchlorateandfueloilwerehandled Thegoldminesclosedintheearly1900sandthesite anddepositedatthesite.Theradioactivematerial withitssmelterwasusedtoprocessarserùc-bearing broughtinfromEldoradoNuclearresultedin silverandcobaltoresfromtheNorthernOntario radioactiveslagmaterialwhichovertimewaspre- minesinCobaltandGowGanda.Theproductionand sentonmuchoftiiesite. marketingofarsenicalpesticides,fromarsenicasa by-productoftiiesmeltingoperations,continuedasa MonitoringandAbatementBegins tankwherelimeisadded.ThelimebringsthepH Intheearly1960stheOntarioGovernment,began leveloftiiewaterupto9.2andferricarsenate,afine, monitoringarseniclevelsintheMoiraRiverand brownishprecipitatebeginstoform.Themixture abatementactivitiesbegan.In1978thesiteowner, thenflowstoathirdtankwhereapolymerflocculant, EricksonConstructionCompanyLimited,was whichisasubstanceofhighmolecularweight,is orderedundertheEnvironmentalProtectionActto addedtohelptheferricarsenateformlargerparti- takespecificmeasurestocontrolarsenicdischargesto cles.Thelargeparticles,whichsettleoutquicklyin theMoiraRiver. theclarifierasabrov^sh,ferricarsenatesludge,are AStopOrderwasissuedin1979againstthe pumpedfromthebottomoftheupflowclarifierto Company.Non-compliancewiththeOrdersissued, thesludgedryinglagoon.Leachatefromtfiesludge combinedwithdiedeclarationbytheCompanyofa dryinglagoonispumpedbacktotheequalization lackofoperatingfundsresultedintheMOEtaking storagebasinforre-processing.Thetreatedeffluent overcontrolofthesiteinthesameyearandwithit with99.5to99.9percentofthearsenicremovedis theoperationoftheexistingarsenictreatmentfacili- returnedtotheMoiraRiver. ty.TodatetheMOEhasspentapproximately$6.5 In1987,8haofferrichydroxidetailings(redmud) millionforsiteclean-upactivitiesandforthetreat- ontheeastsideoftiieMoiraRiverwerecoveredwitti mentofarseruccontaminatedsurfaceandgroimdwa- 05mofcrushedlimestonetopreventwinderosion ter. andparticulatemattercarry-over,toelevatethepH InJuly1992,theOntariodrinkingwaterstandard ofthetailingsandtostabilizethecontainmentdams. forarsenicwasreducedby50percentto0.025mg/L from0.050mg/L. More Remedial MeasuresTaken Otiierremedialmeasuresundertakenatthesitesince NewPlantTreatsArsenic 1979include: In1982MOErenovatedtheformerresearchlaborato- • thedemolitionofunsafestructures; rybuildingandconstructedanew"stateoftheart" • Û\eremediationofspecificcontaminationsources arsenictreatmentplcint.Theplantwasputintoser- suchasthepesticidesbuildingandthearsenicbag- viceinJanuary1983.Thepresentcollection,storage andtreatmentsystemconsistsofan80mlongcon- house; cretecut-offdikealongtheMoiraRiverinthevicinity • theremovalofwasteoilandpesticides; oftheformerarsenicbaghouse,sixpumpingstations • andtheerectionoffencingaroundopenmine oneofwhichpximpsdirectlyfromtheTuttleShaft,a shaftsandworkings. 9084m3clay-linedequalizationstoragebasin,a50m Anumberofstudiesandinvestigationshavebeen by40mvinderdrainedsludgedryinglagoonandthe undertakentoassessthehealth,safetyandenviron- arsenictreatma\tandremovalsystem. mentalproblemsatthesite.Thelatestreportin1990 addressedtherehabilitationandclean-upofthe IHowitWorks smeltingandrefiningplantsiteonthewestsideof Thearsenictreatmentsystemoperatesasfollows: theMoiraRiver. Groundwater,includinggroundwaterandsurface waterdivertedbytheconcretecut-offdikeinthe vicinityoftheformerarsenicbaghouse,ispumped, fromthesixpumpingstationstotheequalization storagebasin.Arserùcconcentrationswhichmay rangefrom50mg/Lto1500mg/Lareequédizedin thestoragebasinformoreefficienttreatment.Atthe treatmentplant,ferricchlorideisaddedinthefirst mixingtankattheratioof25partsironto1.0part arseruc.Themixtureflowsfromthistar\ktoasecond H River Monitored Houriy, DaMyandWeekty NewFunding/StudiesforFurtherCleanup TheMOEhasanextensivesitemonitoringprogram InMarch1992,anagreementwassignedwith forarsenicandheavymetals.Ingeneral,thecurrent EnvironmentCanadaapprovingtheDelorositefor monitoringprogramconsistsofdailymonitoringof fundingimdertheNationalContaminatedSites theplantinfluentandeffluent;weeklymonitoringof RemediationProgram(NCSRP).TheNCSRP,which ei^tstationsalongtheMoiraRiverandsevensta- wasestablishedtoaddresshigh-riskcontaminated tionsrelatedtothetailingsarea;monthlymonitoring sites,isa50/50costsharingprogramfortheperiod ofthesixpumpingstations;andquarterlymonitor- AprU1,1990toMarch31,1995. ingof45groundwatermonitoringwells.Anauto- InJuly1992,workbeganonanin-depthreviewof maticsamplerontheMoiraRiveratHighway#7 theminehazardsatthesite.Thisincludesresearch, takeshourlysamples24hoursaday,everyday.The reviewandcollectionofhistoricaldatawhichwillbe arsenicconcentrationsfromthedailycompositesam- usedtolocate,identifyandsecurethecollapsing plesareusedinconjunctionwiththestreamflow mineworkings.Asurveytopinpointthelocationof datatocalculatetheaveragedailyarsenicloadingsto cillmineworkingsbeganinSeptember1992. theMoiraRiver. Theof)erationofthearsenictreatmentplantand themonitoringoftheMoiraRiverandthesitecontin- ArsenicConcentrationsand LoadingsSubstantiallv ues. Reduced TheMOEhasfinalizedamulti-phased,multi-year Theattachedgraph,"ArsenicConcentrationsin rehabilitationplanforthesitetoaddresspotential MoiraRiver@Hwy#7,1979to1992",showsthat health,safetyandenvironmentalproblems.This éuisenicconcentrationsintheMoiraRiverhavebeen includesupgradestothearsenictreatmentplant,safe substantiallyreduced;however,thetreatmentobjec- closureoftheminesontheeastandwestsideofthe tivesof0.05mg/Lasanannualaveragearseniccon- MoiraRiver,stabilizationoftheredmudtailings centrationand02mg/Lasamaximumarseniccon- area,securementofsitewastes,andthe centrationatanytimecontinuetobeexceededduring demolition/removaloftheinfrastructvireassociated p)eriodsoflowflow.In1979theaverageannual withthesmeltingandrefirungplantsiteontiiewest arsenicconcentrationwas033mg/Lcomparedto sideoftheMoiraRiver. 0.12mg/Lin1991and0.02mg/Lin1986whichis FundingstrategiesforÛ\eimplementationofthe theyearwiththelowestconcentration.Thegraph rehabilitationplanarenowbeingfinalized.Inthe showsaveragemonthlyconcentrations. interim,workisproceedingonthepriorityitemsof Asillustratedbythesecondgraph,"Arsenic theplansubjecttotheavailabilityoffimds. LoadingsinMoiraRiver@Hwy#7,1979to1992", Formoreinformation,contact ïirserùcloadingshavealsobeensubstantially JimRitter, reduced.Theaveragedailyarsenicloadingin1979 DeloroProjectManager, was52.1kg/dcomparedto4.2kg/din1991whichis SoutheasternRegion, theyearwiththelowestloading.Thevaluesshown MinistryoftheEnvironment, areaveragemonthlyloadings. 133DaltonAve, Thelastgraph,"FlowinMoiraRiver@Hw^y#7, Kingston,Ontario 1979to1992",showstheflowintheMoiraRiverin K7L4X6 m^/s.Thevaluesrepresentaveragemonthlyflows. Ph:(613-549^000). ARSENICCONCENTRATIONSINMOIRARIVER @HWY#7 ig7«T01M2 AresnicConoentreiion[mg/L] 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 Yaar ARSENICLOADINGSINMOIRARIVER @HWY#7 1»7«T019a2 AmanteLoading[ke/C^ ^ ^ 1979 1980 1981 1982 1983iT^19H8ii4iiliii1ii9ii8fi5Nii1ii9ia8ii6tlri1^9i8ii7i 198il8i^ii1M9i8ri9iilM1t9^i9i0 199i1ilHiiP199-2 Yaar FLOWINMOIRARIVER @HWY#7 1878TO1S82 Flow[m3/s] 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 Year i;, ;. '