MiningEngineeringAspectsContentsWorlddrivingforceCostsMethodsDesignprinciplesRiskconceptsProjectstageaimsWorldDrivingForceCaveminingisthelowestcostundergroundminingmethod”(DHLaubscher,1994)TotalMiningCostsBlockcavingAUD$24-35/tonneHybridcavingAUD$35-40/tonneSLCAUD$41-60/tonneOpencutAUD$29/tonne(Deeppit>300m)KNOtypestopingAUD$70-120/tonneStrongWorldDrivingForceSince1995,theapplicationofcaveminingmethodshasforcedare-thinkintermsofminingmethodsRe-thinkdrivenby:- Increasepitcut-backcapitalcostsforcingoperationsunderground- Theneedtoproducehightonnagesfromundergroundoperations- Theneedtoattempttoreproduceopen-cutworkingcostsfromanundergroundmine- Pittoundergroundtransitionatlowgradeoperations- BlockcavesequencingAdditionalDrivingForcesNorthParkesPalaborwaMiningworkingscostsaslowasAUD$3.8/tonne+200mhighliftcaveSupercave(>11milliontonnesperyear)BetterminedesignprocessesBlockcaveOPEXECCONOMICFORCESNPV’SAUD$300-400MillionPossibleNPV’S600-800MillionIRR11-25%15%IRRrealisticnumberProjectlife20yearsTotalopexUS$9/tonforblockcavesCut-offgradeCaveMineClassification0to0.25 Mt/yr Small2.5to7 Mt/yr Medium7to11 Mt/yr Large>11 Mt/yr SuperNeedForBalanceCavemininghasmanyadvantagesAgoodunderstandingofthemethodisrequiredTheminingmethodcannotbeappliedtoeveryorebodyRequirements:-Highup-frontcapital-Longerproductionramp-intimes-Gradehighenoughtopayoffcapital-Higherlevelsofdesignwork-ConstructionofanundergroundfactoryCavesarethelargestundergroundminesAparadigmshiftisrequiredforimplementationCavingmethodsCavingMethodsPre-break,SLCorcore&ShellFreecavingmethods,BlockcavingHybridmethods(Blockcaving/SLC)PREBREAK/SLCPre-breakCharacteristicsSLCmostcommonmethodProductionbydrillingandblastingQuickertobringintoproductionthanBlockCavingTypicalminesize2to5million/tonnesyearFreeCavingMethodsBlockcavingmostcommonmethodLowestworkingcostpertonneLongramp-inperiodsHighup-frontcapitalPitorHybridgearing91mlowestblockheightCavede-stressingTypesofblockcaveGrizzlySlusherLHD/panelFrontcaveInclineddrawpointGrizzly(Pillar1981)SLUSHER(HARTLEY1981)SLUSHER(Hartley1981)FrontcaveInclineddrawpointInclineddrawpointBlockcaving-LHDHybridCavingMethodsMixtureofmethodsFluctuatingblockheightsorgeometriesSLC/BlockCaving/FrontCaveStartwithSLC,earliertonnagesRamp-inblockcavingWorkingcosts-LowerthanSLC-HigherthanBlockCavingMethodselectionCAPEX,prebreaklessupfrontOPEX,blockcavinglowerCorporaterisk,blockcaving70%upfrontCavability,pre-breaklessriskSlusher/grizzly,softerrock.LowerstressLHD,coarsefragmentation,highstressGeology,geometry,geotechetcOpencutinteractionPitGearingCaveminingseenasanaturaltransitionfromopen-cutVeryfewminescanrampstraightintolargescaleblockcavingBlockcavingcostssimilartodeeplevelopencutcostsTrend-blockcavingremoveslasttwopitcut-backsSolution-HybridorsharedinfrastructureCaveRiskCavingisoneshotminingGetitwrongmajorproblemsHardtofixHighlevelscapexLargeprojectCAPEX10milliontonblockcaveTotalprojectAUD$1to1.5BillionMinecostsAUD$350to600millionShaft/declinesystemAUD$60-90million60%CAPEXinfrastructureUS$200MillionruleRISKIMPACTS30-40%CapitalblowoutAUD$250-300Million30-40%recoveredgrade30-50%lessproductioninyr15yearslongertoachievefullproductionTypesofCaveRiskImplementationtimesDesigndetailMiningengineeringrisks-Geological-Geotechnical-ManagementImplementationtimesSlow-15yearsFasttrack-7years(superteam)Highlyaggressive-6yearsAverage10yearsSuperteampersonnelexistintheworldSmallSLCtypeoperations3yearsBrownfield'sFC5yearsDesignDetailRockfactoryconceptHighlevelsofdetailrequiredineveryaspectSpecialiststudiesMiningEngineeringRisksGeological-highblocklift,bottom-upmethodGeotechnical-extractionlevelcrushing,dilution,water/mudingressesWorkforceskillsRiskAmeliorationCavingriskscanbemitigatedby:-Theuseofthe‘‘superteam’-Understandingthathighlevelsofdesigndetailarereq.-Sanitychecks(implementationtimes)-Hybridsystem-Correctmodellingtechniques-RiskanalysisCaveprojectsCriticalmistakesSpendtoolittletimeonconcepts-Miningmethodselection-Mininggeometry-Blockattack-CorporateriskprofileUnrealisticexpectationsDesktopStudyAimsIscaveminingpossible?Coulditbeseenasanalternativetoopencutmethods?Deeplevelorebodies?ProjectconfigurationCouldthestudiesbeadvancedbeyondtoscopingstageIstheprojectviable50%accuracy(Reynolds)BestpossibleinputvaluesBlockcavesbestafter250mliftifnot400mScopingstudyGeneralfeaturesofproject-Cavingfootprint-Cavingblockheight-Bottomofopencut-MiningmethodselectionBestparameters30-35%accuracyDon’tworryaboutcavabilityExperiential,empiricalinputparametersWelloverhurdles,IRRcandropby10%toDEFSWrong-toomuchdetailScopingstudyconceptsWorkonexperience,doesitfeelrightIfsomeonehasnotcavedit.Itwillnotwork/orishighriskURAD/PhilexDesignfrombooks(MASSMIN92&2000)ConfidencewithconceptsGeotechnicaldesignwithrockmassratingsDonotuseratingvaluespassedscopingstage.RamptonnageassessmentswithBCF/Hang-upmodelWhatneedstobedonefornextstageGeotechnicaldomainmodels,forholesandsenseSTUDYCONCEPTSNoguru’sUsemethodswithatrackhistoryWhatisthestudybasis:-Negativeexperience-Everythingdonerigh