Optimized_060525_Martha_Hill_Case_Study_Scott_McEwing.ppt

MarthaMinePresentation,MarthaMineBackground,MarthaMineisanmodernmediumsizedopenpitmineinNewZealand.Themineextractsgoldandsilverfromthemineralisedquartzrock.Themineisrelativelyuniqueinthatitoperatesadjacenttoatown.TheenvironmentalrestrictionsareverytightItsetsahighstandardinoperatingandmanagementtomeetitsrequirementsItprobablyisanexampleofhowAustralianoperationswillbeexpectedtooperateinthenearfuture.,Historical,ThedepositatMarthaMinewaspreviouslyminedundergroundtechniquesfromthe1878’sto1956beenmined.TheundergroundoperationwasthelargestinAustralasiaanyyears.Undergroundminingstoppedwhenthecostofpumping,lowgoldpricesandfallinggradereducedprofits.Theoldtimersusedvariousminingsincludingcaving,cutandfillandopenstoping.Theyleftbehindanythingunder20g/t.Thesevenshaftsandvariousworkingscreatehazardsforequipmentintheopenpit.TheareaaroundMarthaMineishighlymineralised.,Location,,Location,,Geology,Geothermalareas,,Onehundredyearsago,CornishPumphouse,CornishPumphouse,1980’s,StartofSurfaceMining,Geologyrevisited,MiningOperations,MiningEquipment,TheExpansion,TheCommencementoftheExpansion,Dewatering,Theopenpitrequireddewateringtopreventthepitfromflooding.Annualrainfallinthispartofthecountryisapproximately2.5m/year.,WasteEmbankmentConstruction,OldandNewWasteDumpsandTailsDam,Theimpactof“OldMineWorkings”,,At1215amon13Dec2001,asinkholeabout40metresindiameterdevelopedonthesouthwesternmarginofBarryRoad,midwaybetweenSeddonStreetandKennyStreet.Thesinkholedevelopedsuddenlyandengulfedaresidentialsectionandhouse,partsoftheadjacentsectionsandtheroad.,,,Rehabilitation,OldandNewWasteDumpsandTailsDam,ProposedRehabilitatedMine,AnArtisticImpression,ProposedRehabilitatedWasteDumps,TheUndergroundProject,,,