hydrogeology and ground water quality at the … · unc mill site ground water history 1980s-2015...
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HYDROGEOLOGYANDGROUNDWATERQUALITYATTHEUNITEDNUCLEARCORPORATIONURANIUMMILL,CHURCKROCK,NEWMEXICO
EarleC.DixonEnvironmentalScienEst
TsaliAssociates
UNCMillSite–RegulatorySeKng• NuclearRegulatoryCommission(NRC):Responsibleforallonsite&beneaththefacility,insidepropertyboundarythroughlicense.
• EnvironmentalProtecEonAgency(EPA)Region6:Responsibleforoffsitegroundwatercleanup&exposurethroughCERCLA-NPL&1988ROD.
• NRC&EPAworktogetherunderanMOUtocleanupthesitetoUMTRCA&RODstandards.
• NMED&NavajoNaEonparEcipateindocumentreview-comment&decisionmaking-comment.
• Sitebecamemorecomplicatedw/planneddisposalofminewasteatUNCcentral&northdisposalponds.
EPARegion6,Dallas:UNCMillSite
EPARegion9,SanFrancisco:NECRMineSite
Southwestalvm(SWA)
Zone3,(Z3)
Zone1,(Z1)
MonitoringwelllocaEonmap2015,UNCMill,ChurchRock,NM
ChurchRockmineswaterdischargerates(gpm),
1968-1986
Zone3monitoringwellSWLdecline
projecEontoboeomofscreenelevaEon
2012GroundWaterFlowModelZone3seepage
Projectedmonitoringwelldrydates,Zone3,UNCMillSite,ChurchRock,NM
UNCMillSiteGroundWaterHistory1980s-2015(1of4)
• 1968:NECRstartsminingoperaEons,dewatering,1977UNCstartsmillingoperaEons,seepageproblemsby1981.
• 1979:Southtailingspondbreach.• 1980-1988:controversialperiodofinvesEgaEons,lawsuits,hearings,regulatorchange,&miningindustrydecline&closure.
• 1983:UNCMillSiteplacedonNaEonalPriorityList(NPL)orSuperfundforgrdw.
UNCMillSiteGroundWaterHistory1980s-2015(2of4)
• 1988RecordofDecision(ROD):selectedAlternaEve3–pumping&evaporaEonw/mistersfor3aquiferunitstostandards.
• ROD-onetableofgroundwatercleanupstandardsforthreedifferentaquiferunits.
• CleanupstandardsareacombinaEonofsitedata,laboratorydetecEonlimits,&healthrisklevels.
• Remedydidnotachievestandards&pumpflowratesbelowEPAcriteriasoremedyshutdownby2001.UNCconEnuesZone3pumping.
UNCMillSiteGroundWaterHistory1980s-2015(3of4)
• UNCrequestedalternaEvestopumping:technicalwaiverforstandards;insEtuEonalcontrols–nosupportfromNN,BIA,NMED.
• 2004-2006:beginformalprocesstoevaluateotherremedies&buildadecisionsupportdocumentrepositorytorevisethe1988RODcleanupstandardswhichneedrevision.
• 2006:SiteWideSupplementalFeasibilityStudy(SWSFS)beganinaphasedapproach.
UNCMillSiteGroundWaterHistory1980s-2015(4of4)
• 2008:Part1SWSFScompleted,ProUCLstaEsEcalstudyofUNCgroundwaterdatatocomputerevisedbackgroundvaluesforearlyCOCvaluesthatwereusedas1988RODstandards.
• 2010:Part2SWSFSAlternaEveremedyscreeninganalysis&costesEmateaccordingcompletedtoEPAcriteria.
• 2017:(?)Part3DetailedalternaEveremedyanalysis&costtoachieverevised/proposedvaluesforupdatedRODstandards.
PrimarygeochemicalreacEonforbufferingseepageimpactedgroundwater
Uv.HCO3CovariantRelaEonship
UNCMillSite–Status&Future• 2015:NRCapprovedAmendment52toUNCLicenseto
reviseGroundwaterProtecEonStandardsforselectmetals&radionuclidesin3hydrostraEgraphicunits.
• 2016-2017++:Part3SWSFScompleted(?)thenEPAsystemaEcallystartsrevisionprocessto1988ROD?
• Lookingforward:UNCSiteneedstoachieveclosure&beremovedfromNPLinordertomovesitestewardshipunderUMTRCAtoDepartmentofEnergy(DOE)LegacyManagementbytransferofLicense.
• NECRminewastetobedisposedatUNCSite&closedunderNRCLicense-neverbeendonebefore?
• NRC,EPAs,NN,UNC-GE,&DOEworkingtogether.• DOEwillbecomelong-termsitemanager??
The End.
Thank you.
Questions-Comments?