FFiinnaall RReeppoorrtt
BHP Billiton Iron Ore
Stygofauna Assessment
at OB29/30/35, Mount Whaleback
PPrreeppaarreedd ffoorr BBHHPP BBiilllliittoonn IIrroonn OOrree
bbyy BBeennnneelloonnggiiaa PPttyy LLttdd
AApprriill 22001133 RReeppoorrtt 22001133//119900
BennelongiaPtyLtd OB29/30/35StygofaunaAssessment
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StygofaunaAssessmentatOB29/30/35,MountWhaleback
BennelongiaPtyLtd5BishopStreetJolimontWA6913www.bennelongia.com.auACN124110167April2013Report2013/190
BennelongiaPtyLtd OB29/30/35StygofaunaAssessment
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LIMITATION:ThisreviewhasbeenpreparedforusebytheClientanditsagents.Bennelongiaacceptsnoliabilityorresponsibilityinrespectofanyuseorrelianceonthereviewbyanythirdparty.BennelongiahasnotattemptedtoverifytheaccuracyandcompletenessofallinformationsuppliedbytheClient.COPYRIGHT:Thedocumenthasbeenprepared to the requirementsof theClient. Copyrightandanyother Intellectual Property associated with the document belong to Bennelongia and may not bereproducedwithoutwrittenpermissionoftheClientorBennelongia.ClientBHPBillitonIronOrePtyLtdReport Version Preparedby Checkedby SubmittedtoClient Method DateDraftreport Vers.1 AndrewTrotter StuartHalse email 6.ii.2013Finalreport Vers.1 RowanLymbery
AndrewTrotterStuartHalse email 3.iv.2013
Vers.2 AndrewTrotter StuartHalse email 26.iv.2013K:\Projects\B_BHPBIO_36\DraftReport_BEC_OB29_30_35_stygofaunaassessment_final26iv13
Coverphoto:Paramelitidaesp.B33
BennelongiaPtyLtd OB29/30/35StygofaunaAssessment
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EXECUTIVESUMMARYBHPBillitonIronOrePtyLtdisproposingtominebelowthewatertableattheexistingminingoperationsassociatedwithOrebodies29and30(OB29andOB30)andatanapprovedmineatOrebody35(OB35)intheOphthalmiaRangenearthetownofNewmaninthePilbara(theProposal).OB29,OB30andOB35aresatellitedepositsoftheexistingMountWhalebackmineatNewmanandliein a syncline approximately 1.5 kilometres (km) to the south of themainMountWhalebackminingoperations.TheproposedminingatOB35willutiliseexistinginfrastructureatMountWhaleback.An environmental impact assessment isbeingprepared as thebasis for approval tominebelow thewatertableatOB29,OB30andOB35deposits.ThemaingrounddisturbancecomponentsandactivitiesproposedtobeassociatedwithminingbelowwatertableatOB29,OB30andOB35areasfollows: Progressiveopenpitminingbelow thewatertableofoverburden andoreusing similaropenpit
miningtechniquestothosecurrentlyapprovedforminingandinuseatOB29andOB30;and Dewateringoflocalaquiferstopreventminepitflooding.Dewateringmaycausesignificantthreattorestrictedstygofaunaspeciesasaresultof lossofhabitat.For the purpose of assessing threat to stygofauna associatedwith Proposal development, predicteddrawdown>2mfromnaturalfluctuationswasconsideredtoconstituteapotentiallysignificantimpact.Field surveyof stygofauna in the vicinity of the Proposalwas conducted accordingwith the generalprinciples laid out in EPAGuidance StatementsNos 54 and 54A. Altogether 43 samples have beencollected within the area where predicted drawdown is >2 m. This survey effort meets EPArecommendations. Furthermore,becauseanadditional1658sampleshavecollectedelsewhere intheNewmanarea (mostly to theeast), there isabetter localcontext for thisassessment thananyotherconductedtodateinthePilbara.Withonlyninespeciesrecorded,theProposaldrawdownareaisdepauperate instygofaunacomparedwith thewiderNewman area,which has at least 53 species. Themost likely explanation for fewerstygofaunaspeciesintheProposalareaisthatitcontainspoorerqualitystygofaunahabitatthansomeotherpartsoftheNewmanarea.ThereisonlyasmallareaofsaturatedTertiaryDetritalsand,notably,nocalcretewithintheProposaldrawdownarea,whereassignificantareasofthesehabitatsoccurinthewiderNewman area. Themainhabitat in theProposal area isbanded iron formation,which is lessprospectiveforstygofauna.All the species collected within the area of predicted groundwater drawdown associated with theProposal (the impact footprint) are also known,or consideredhighly likely, tooccur in locationsnotimpactedbyminingandassociatedactivities.Habitatcharacterisationandstygofaunasamplingresultsprovided a similarpicture in termsof suggesting that stygofaunahabitatwithin theProposal area isconnected with stygofauna habitat in the downstream Ophthalmia floodplain. Species such asChydaekatasp.andParamelitidaesp.B33occurredinbothareas.Noneof the stygofauna species collected in the Proposal impact footprint is considered likely to berestricted to,orhaveasubstantialproportionof itspopulationwithin, theProposal impact footprint.Therefore,proposeddewateringatOB29,30and35isunlikelytohavesignificantconservation impactonanystygofaunalspecieswithintheProposalarea.
BennelongiaPtyLtd OB29/30/35StygofaunaAssessment
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CONTENTSEXECUTIVESUMMARY..........................................................................................................................................III1.INTRODUCTION.................................................................................................................................................12.STYGOFAUNA....................................................................................................................................................3
2.1.HABITATREQUIREMENTSFORSTYGOFAUNA.................................................................................................................33.PROJECTIMPACTS..............................................................................................................................................3
3.1.PRIMARYIMPACTSATTHEPROPOSAL..........................................................................................................................44.HABITATASSESSMENT.......................................................................................................................................4
4.1.GEOLOGY...............................................................................................................................................................44.2.HYDROGEOLOGY.....................................................................................................................................................64.3.THEPROPOSALAREAASSTYGOFAUNAHABITAT............................................................................................................6
5.STYGOFAUNASURVEYS.....................................................................................................................................65.1.1.StygofaunaSurveysRelevanttotheProposal.............................................................................................65.1.2.SamplingattheProposal............................................................................................................................75.1.3.SamplingMethods......................................................................................................................................75.1.4.OtherSampling...........................................................................................................................................7
6.RESULTS.............................................................................................................................................................76.1.STYGOFAUNAOCCURRENCEANDABUNDANCE..............................................................................................................76.2.SPECIESIDENTIFICATIONISSUES................................................................................................................................116.3.STYGOFAUNADISTRIBUTIONS..................................................................................................................................11
7.DISCUSSIONANDCONCLUSION.......................................................................................................................117.1.1.StygofaunaOccurrenceandHabitatConnectivity....................................................................................117.1.2.ConservationRiskforSpecies....................................................................................................................12
8.REFERENCES.....................................................................................................................................................129.APPENDICES.....................................................................................................................................................14
Appendix1:SecondaryImpactsofMiningonStygofauna.................................................................................14Appendix2:ExamplesoftheProposalAreaStratigraphy..................................................................................15Appendix3:StygofaunaSamplingintheNewmanArea....................................................................................20Appendix4:CoordinatesofBoresSampledforStygofaunaattheProposal......................................................22Appendix5.StygofaunaCollectedattheProposal.............................................................................................23
LISTOFFIGURES
FIGURE1.THEPROPOSALSITE(PANELC)INRELATIONTOOTHERLOCATIONSSAMPLEDDURINGTHEBHPBILLITONIRONOREREGIONALSUBTERRANEANFAUNASAMPLINGPROGRAM.................................................................................................................2
FIGURE2.PITOUTLINESANDEXTENTOFGROUNDWATERDRAWDOWNASSOCIATEDWITHTHEPROPOSAL.........................................5FIGURE3.BORESSAMPLEDFORSTYGOFAUNAWITHINTHEIMPACTAREAASSOCIATEDWITHTHEPROPOSAL.......................................8FIGURE4.CAPTUREABUNDANCEOFEACHSTYGOFAUNASPECIESRECORDEDATTHEPROPOSAL........................................................9FIGURE5.LOCATIONSWHERESTYGOFAUNAWERECOLLECTEDATTHEPROPOSAL....
