expertsmicromedia

Areassuchasoptimisation,modellingandlaborpilotscaletestworkarenowcrucialingettingitrightwhenitcomestocomminutionatwhateverparticlesizeandprocessstage.
Butjustasinrealitythereisnoaverageoreorrocktype,everycomminutionapplicationisuniqueandrequiresitsownstudy.
Byputtingupalternativesagainsteachother,capitalandoperatingcostscanbecalculatedandcomparedinordertofindanoptimalsolutionforanindividualapplicationcase.
Thiscanrequireco-operationbetweenequipmentOEMs,academics,consultantsandengineeringgroupstogetherwiththemininggroups,tocomeupwithawayforward.
SpecialisteventssuchasSAG2011andComminution2012helptobringthesestakeholderstogetheranddrivetechnologyadvances.
Argumentscanevencomedowntotherelativeimportanceofcrushingversusmilling/grindingintermsofcostandefficiency.
Anddespitethemovestowardsevermoreadvancedmilling/grindingcircuits,crushertechnologyisnotstandingstill.
RobertPicard,ApplicationsMarketer-MiningCrushing&ScreeningatSandvikcomments:"Millingisthedominantenergyconsumeraswellashavingahighcostformillmedia.
Webelievethereforethatitisgenerallycheapertocrushthangrindinsizereduction.
Today,withmoreefficientcrushersacircuitcanbebuiltwithfewerunitsandespeciallyalowerenergyrequirement.
Linersincrushersareexposedtowear.
However,designandoperationofamoderncrushermakesitpossibletohaveahighdegreeofinterparticlecrushingratherthanagainsttheliners.
Thishasimprovedcostforwearpartsconsiderably.
Stillcrushersrequiremorefrequentmaintenancethanmills.
Howeveritcanbedealtwithiflinerchangesareplannedintoscheduledmaintenancestopssothatproductionlossisminimisedoreventotallyeliminated.
"UltrafinegrindingUltra-finegrinding(UFG)remainsakeyareatoachievehigherrecoveryratesinmanymineralprocessingapplications.
Butmillingisinherentlyinefficientandthisinefficiencyincreasesdramaticallyastheparticlesizedecreases.
CurrentdevelopmentsinUFGmillshavetendedtowardshighintensitymillswithhighrotationalspeedsandgrindingdisktipspeedsrangingfrom12to20m/sec.
Thisiscoupledwiththedevelopmentofhigherdensitymediatohelpachievehigherbreakagerates.
Aninstalledpowerof3MWiscommonandinstallationsofupto8MWarerunningsuccessfullywiththepotentialforevenlargerexamples.
Butwithresearchsuggestingthataslittleas3-5%oftheinputenergyisactuallyusedforgrinding,someintheindustryarguethatthereisconsiderablescopeforenergysaving.
MaelgwynMineralServices'(MMS)newtwindrivehorizontalmilldevelopmentaimstoreducethiswasteofenergybyusinganoveldriveandgeneratorsystemtoreclaimandrecycleenergyfromthemovingmediamasswhilegrinding.
Itconsistsofarotatingdrumfittedwithwallmountedgrindingdisks,driventhroughagearboxandaninternalshaft,alsofittedwithgrindingdisks,coupledtoamotorbutconfiguredasagenerator.
Theinterspaceddrumandshaftmounteddisksformalabyrinthfortheslurryflow.
MMShasbuilttwoprototypemills,a400mmdiameterdrumwithaninternalvolumeof30landan800mmdiameterdrumwithaninternalvolumeof150l.
Thedrumisdrivenatamaximumrotationwhilethefrictionalresistanceofthemediaontheinternalrotor,inturn,drivestherotor.
Theinternalrotorisbrakedelectricallytocontrolthespeedoftherotorsothattherelativerotationalmotionandconsequentgrindingactioncanbeoptimised.
Theinvertersthatcontrolthedrummotorandrotormotor(asagenerator)areconfiguredsothattheenergygeneratedbytherotorcanbefedbacktothedrumdrive.
Thepowerdemandonthemainsupplyisreducedtothedifferencerequiredbythesystem.
Theinterspaceddiskssegregatethemediaintoindividualgrindingchambersthatreduces00InternationalMining|MARCH2012DusttodustFromprimarycrushingtoultrafinegrinding,newcomminutiontechnologycontinuestogiveminestheedgeinrecoveryandefficiency,reportsPaulMooreCOMMINUTIONAnXstrataTechnologyM10000IsaMill,similartotheonethatwillbecommissionedatRussianCopperCompany's(RCC)MiheevskyprojectinCheylabinskthehydraulicpackingofthemediaandtogetherwithanoveldiskdesign,providesanaxialloadonthemediatoincreasetheforceappliedduringmediainteractions.
The400mmmillhasbeentestedquiteextensivelyrecentlyusingflyashinaprojecttogetherwithCardiffUniversity.
Thedatageneratedbythisinitialtrialphasehasshownthattheconcepthassomepotential.
ThetrialscarriedoutatCardiffUniversityhavebeendesignedtoprovetheconceptbuthasalsocomparedthetwindriveconcepttotypicalhighintensityhorizontalandverticalmillconfigurations.
Theinitialtestresultsshowedsavingsof30%onspecificenergytoP90of10μm,and15%toP90of5μmfromafeedF90of275μm.
ComparativetestworkwascarriedoutusingSaintGobainZirmilmediawithspecificgravityof6.
2and2mmdiameter.
Currentanalysissuggeststhatmoreefficientresultscanbeobtainedwithfinerbeadsizesandlowerdensitymedia.
Zirmilareceramicmicrogrindingbeadsproducedfromauniqueyttria-dopedzirconiapowder.
ThroughitsresearchpartnershipatCardiffUniversityMMShasalsoinvestedinDiscreteElementMethod(DEM)andComputationalFluidDynamics(CFD)analysispackagestoaidintheunderstandingofthemillingenvironmentandtheeffectsoftheprocessvariablesontheperformanceofthemill.
TheimpactfrequencyandtheenergydistributionthroughoutthemediavolumeiskeytounderstandingthegrindingmechanismsinvolvedinUFG.
Thissoftwarehasbeenusedtomodelthetwindrivemillconfiguration,aswellassomecomparativeconfigurations.
Theactualmilldatawasthenusedtoverifythemodelandarelativelyhighcorrelationwasachieved.
MMStoldIM:"Thisanalysishasbeenindispensableinexplainingthedifferencesingrindingmechanisms,andespeciallywhatisbehindthegoodperformanceatbelow10μm.
DEManalysisofthetwindrivemillandcomparisonwithmodelsofhighintensitymillsshowsanorderofmagnitudeincreaseinthefrequencyofimpactsperbeadinthemill,withamoreuniformenergydistribution,indicatingthatthetwindriveconceptincreasesitsefficiencybyeffectivelyusingagreaterpercentageoftheoverallvolumeofmedia.
"Otherhighintensityconfigurationsrelyonaverysmallportionofthemediavolumelimitedtotheimmediateinnercircumferenceofthedrumwhereexcessivelyhighintensityimpactseffectedthegrindingwhilethebulkofthemediacontributedverylittle.
CFDanalysiswasusedtoinvestigatetheflowofslurrythroughthemill.
Whilstnotanessentialparameterfortheanalysisofthetestworkthatwascarriedout,asallthemillswereoperatedinabatchmode,intermsofscaleuptoafullscaleinstallation,theresidencetimedistributionisanimportantfactor.
Allthemillsshowedfairlynormaliseddistributioncurvesbutithasshownthattheauto-classificationeffectoftheverticallyorientatedmillprovidesameasurablebenefittoefficiencyandgrindcurvecontrol.
Furthertrialsareplannedasthereisstillasignificantamountofworkrequiredtofullyunderstandthepotentialofthisconfiguration.
Thesetrialsaimtooptimiseenergycapture,diskdesignandbeadspecificationoverawiderrangeofsubstrates.
AtechnicalpaperwillbepresentedattheMEIComminution2012conferenceinSouthAfricafromApril17-20providingmoredetailonMMS'smilldevelopmentandthetestworkthathasbeencarriedout.
UFGtechnologyreliesonthemicro-beadqualityaswellastechnicalassistancetogetthebestresultsforMainstreamInertGrinding(MIG)andUFG.
IndustrieBitossiisagloballeaderintheproductionofAl2O3basedgrindingbeads.
Thecompanystates:"OurR&Ddepartmentcontinuouslyinvestigatesnewformulasinordertoachievelowerconsumptionrateandhighergrindingefficiency.
Inordertokeepthecostsdownourresearchaimstoachievethebestresultswithaluminaproductsintermsofwearandenergysavings.
Aluminamicrobeadspropertiessuchaschemicalcomposition,hardness,smoothness,roundness,specificgravityandmicrostructurehavebeenspecificallytailoredforhighintensitystirredmilling.
Thesmoothsurfaceofthebeadsreducesthelossofenergycausedbyfriction,itincreasesenergyefficiencyanditgrantsalongerlastinglifetotheinternalmillwearcomponents.
"Inadditiontothis,thecompanypointedoutthebenefitsofinertgrindingintheflotationprocess.
Consideringthatformetalrecovery,ultra-finegrindingrepresentsaveryhighpercentageofthetotalcosts,theusageofcost-effectivemicro-mediaconsiderablyhelpstoreduceoveralloperationalcosts.
Asidefromin-houselabtesting,fortechnicalassistance,thegroupcanassistminingcustomersonsiteinordertoverify,onanindustrialscale,beadwearresultsandalsoevaluateempiricallyalltheparametersinvolvedinthegrindingprocess.
Thecompanystates:"Wehaveexperiencedhowimportantitistoworkon-sitetohaveaclearpictureofwhatitcanhappenduringthegrindingprocess.
Inthiswaywecansharewitheachsinglecustomertheexperienceofmanyplantslocatedallaroundtheworld.
Streamlinedgrindingconditionsoptimisethemicro-beadsperformancewithaconsequentbeadswearcutdownandtheystabilisethefullplant.
Wehavealsofoundthat,toavoidabnormalincreasesinmicro-beadwear,itisveryimportanttohaveaconstantslurryflowintermsofquantityandsolidscontent.
"Thegrindingchargedistributionhastocomplywiththemillsize,rawmaterialchemicalandphysicalfeatures,rawmaterialgrading,endparticlegrading,andmillrotationspeed.
Grindingchargesaredevelopedtohave,foreachspecificapplication,themostefficientmicro-beaddiameter,fractionandsizeforrefilling.
UFGisalsoapplicabletoprocessoptimisationtechnology.
Loesche'sLM_Masterisanewmodel-basedpredictiveprocessoptimisationforecologicallyincreasingplantperformanceandsupporttheoperatorsofLoescheverticalmills.
LM_Masterprovidesforfullyautomaticcontrolofthegrindingprocessandcontinuouslyoptimisesregularplantoperation.
Onlineoptimisationisachievedthroughprecisedepictionoftheprocessesandincreasesthroughput,energyefficiencyandavailability,statesLoesche.
Thecompanycomments:"Themostimportantcomponentinputtingsuchaprojectintopracticeisknowledgeofallaspectsoftheprocess.
Loeschehasthenecessaryexperienceandknow-howfromadiverserangeoffieldssuchasautomation,commissioningandservicing,design,andR&D.
Thisknowledgemakesitpossibletocreatemodelswhichreflecttheprocessasaccuratelyaspossibleinordertobeabletoderivethenecessarycalculationsfromthem.
Thesecalculationsshowthefuture00InternationalMining|MARCH2012COMMINUTIONEirichMaxMillwithBitossialumina-basedultrafinegrindingbeadsplantstatuswiththeaidofhistoricdataandcurrentprocessvalues,manipulatedvariablesanddisturbancevariables.
Theverticalrollermillisstabilisedduringregularoperationbymeansofacontinuousadaptationofthecontrolleroperatingpoints.
Theplantisthereforeoperatedascloselyaspossibletoitsspecifiedlimits.
Thisinturnincreasesplantperformance.
Thesoftwareplatformrequiredforthispurposeis,irrespectiveofthemanufactureroftheautomationsystem,installedonaseparateindustryPC.
Withonlyafewinterventionsintheexistingautomationsystemandlowinvestmentexpenditureitisthuspossibletoincreasetheefficiencyofthegrindingplant.
"ThenewprocessoptimisationsolutionisintendedforusewithLoescheverticalrollermillsinallareasofmaterialcomminution.
Theapplicationisalsointendedforbothnewinstallationsandexistinggrindingsystems.
ThedrymillingoforesinLoescheverticalrollermillshassignificantprocessadvantages,aswellaseconomicandecologicalbenefits,accordingtothegroup.
Todemonstratethese,amobileore-grindingplant,theOGPmobile,hasbeendeveloped.
ThisallowsthecustomertotesttheeffectivenessofLoesche'sgrindingtechnologyanditsinfluenceonthetotalmaterialflowoftheexistingprocessingplant.
Thedegreeofmineralliberation,particlesizedistribution,energyconsumptionandthroughputcanbeoptimisedindividuallyforeachdepositandeachtreatmentprocess,dependingontheorecharacteristics.
ThemainadvantagesoftheLoeschegrindingtechnology,comparedtoconventionalmillingtechnology,arestatedas:increasedvaluerecoveryduetoimprovedmineralliberation;reducedoperatingcoststhroughlowerspecificenergyconsumption;lesswearofgrindingparts;narrowparticlesizedistribution;rapidadaptationtochangesinorecharacteristicswithinadeposit;automaticallycontrolledmillcircuitusingonlinecontrolsystem;andreducedtotalwaterconsumptionduetodrygrindingandclassifying.
Loeschetoldthatpastexperiencehasshownthatthesebenefitsareachievableonvariousoretypeswithdifferingcharacteristics,suchaslead/zincandnickel.
TheOGPmobileisafullyfunctionalgrindingplant,whichiscomparablewiththetestcircuitsintheLoescheTestCentreinNeuss,Germany.
Theflexiblecircuitallowsoperationinanairflowaswellasinoverflowmodewithoutexternalclassifying.
Largesamplesofmilledmaterial–200-300tforfurtherdirectprocessinginsubsequentprocesssteps–canbeproduced.
Thequalityofthemilledproductsischeckedbyanalysisintheintegratedlaboratory.
TheOGPmobileconsistsofthree,40ft-long,cubicprofileoceancontainers,whichmakesglobaltransportationeasy.
Themechanicalequipmentforgrinding,sizing,materialhandlingandproductseparationisinstalledintwocontainers.
Inthethirdone,thelaboratoryandprocess-controlsystemisinstalled,alongwiththecontrolroom.
TheminimumrequirementsforoperatingtheOGPmobileareanappropriatepowersupplyandacompactedbasemeasuringapproximately17mx7m.
ThefirstOGPmobileiscurrentlybeingusedinsouthernAsia,whereitstransporttositewashandledbyLoeschelogisticsexperts.
Theoperationofthefacilityandthetestingprogramisbeingcarriedoutincloseco-operationbetweenthecustomerandwithLoeschespecialistson-site.
Aftertheseriesoftestshasbeencompleted,furtherdeploymentsareplanned.
InadditiontotheOGPmobile,LoescheofferstheContainerisedGrindingPlantorCGPmobile.
Thisnewlydevelopedcontainerisedconstructionplantprovidesforthelocalsupplyofthermalprocessesandcanbeusedatanysite.
Thisplanttypefillsthegapinthesupplyofcoaldustinthatiteliminateslongtransportationroutesinspecialvehicles.
TheuseofcoalinsteadofgasandoilthatismadepossiblebythisplantreducesoperatingcostsdramaticallyaccordingtoLoesche.
Intheminingindustry,theneedforefficientfinegrindingprocessesisincreasingrapidly.
Asdemandfororeswithfinermineralintergrowthrises,grindingtechnologyisbeingdevelopedtokeepup.
JonAllen,Metso'sProjectManagerforStirredMillingTechnologies,notes:"Whatwe'reseeingnowaredepositsthathavemorefinelydisseminatedvaluablemineral.
Thefactis,thosedepositsrequirefinergrindingtoachieveadequateliberation.
"Thechallengeinfineandultrafinegrindingapplicationsistheincreasingenergyrequirementsandthediminishingreturnsthatoccurasoperationsapproachsmallerproductsizes.
ThesolutionMetsoarguesisenergy-efficientstirredmillingmachinerythatmaximiseswearlifeandavailability–allwhileachievingdesiredproductsizeandmaintainingprofitability.
ThissolutionCOMMINUTIONMARCH2012|InternationalMining00ThenewSMD-1100-E,Metso'slargest-scaleStirredMediaDetritorThenewOGPmobileisafullyfunctionalmobilegrindingplanthasevolvedintothemostcost-effectivefinegrindingtechnology–fromtheVertimilltothelatestStirredMediaDetritor(SMD)E-Series,featuringtheSMD-1100-E,Metso'slargest-scaleSMD.
TheVertimillandSMDarenotcompetitors,butweredevelopedascomplementaryproducts.
TheVertmillcanworkwitha6mmto20micronfeed,andtheSMDfrom100micronstoa5micronfeedsize.
Metsostates:"TheSMD-1100-Eisbringingefficientultrafinegrindingtolarge-scalethroughput.
Thismachineisthefutureoffinegrindingbecauseitsefficiencyandspecialisationenableittoprovidethelowesttotalcostofownershiptooperatorswhoneedtoachievefinegrinds.
"Itisoftensaidthatlowesttotalmediaconsumptionisamajorinfluenceroflowesttotalcost.
However,ifamachinerequireslessmedia–butatahighercostpertonne,the"savings"affordedbylowermediaconsumptionareeclipsedbythematerialcost.
Theconsumables–thegrindingmedia–arethenumber-oneoperatingcostinamill.
TheentireSMD-E-Series,includingtheSMD-1100-E,offersthelowestcostpertonneprocessedofbetween$300and$1,300accordingtoMetso.
WithlowerenergyinsidetheSMD-E-Seriesmills,thewearlifeisalsoextended.
Thecompanystates:"TheincreasedvolumeoftheSMD-1100-Eiskeytomaximisingthecost-savingpotentialoflower-intensitygrinding.
Butspaceisalsoanimportantconsiderationinaplant,andthesolutionwastogovertical.
Bydoingthis,wecanmakeuseofalargervolumewithoutworryingaboutaffectingthefootprintoftheunit.
Anadditionalbenefitofaverticallyconfiguredmachine,whencomparedwiththehorizontalunit,isasimplermechanicaldesign.
Becausethevesselsarepressurised,horizontalstirredmillingmachinesrequireshaftseams,feedpumpsforslurryandmedia,plusadditionalshaftbearings,andmoreconcreteforthefoundation.
TheSMD-1100-Eisastreamlinedunitthatcanachievehigheravailability.
"Withregardtomaintenance,everywearcomponentoftheSMD-1100-Ecanbechangedwiththemillinplace–withoutremovingordisassemblingtheshell.
Additionally,thetopplatecanberotatedin45°increments,andsideplatesareinterchangeableformultiplefeedarrangements.
MetsoalsokeptancillaryequipmenttoaminimumwiththeSMD-E-SeriesasonlyonepumpperSMDisneeded–notfiveorsixasonotherstirredmilldesigns.
Maintainingonepumpismuchsimplerandlessexpensive.
"AfterinstallingasmallerSMD-355-EattheMototoloplatinummineinSouthAfricaandseeingtheoperationalbenefits,AngloAmericanwantedtoscaleup.
"TheSMDallowsustoachievefinegrindsatahighlevelofefficiency,"saysChrisRule,HeadofConcentratorTechnologyatAngloPlatinum,"andthemechanicalimprovementswiththeE-seriesresultinmoreuptime.
Inanyoperation,that'showyouachievelong-termsuccess:themoretonswegetthrough,themorerevenuewe'llsee,andtheSMD-1100-Eisgoingtohelpusdothat.
Italwayscomesbacktoourbottomline.
"AngloPlatinumexpectstheSMD-1100-Etoprovidethelongestwearlifeandhighestuptimeofanyfinegrindingtechnologytheyhavetrialled.
Theunitisscheduleforstart-upinSeptember2012attheAngloPlatinumUnionMortimerconcentrator.
HPGRsandIsaMillMovingfromUFGtechnologytoothermillingandgrindingdevelopments,highpressuregrindingrolls(HPGRs)continuetogetalotofattentionintheindustry.
CoalitionforEco-EfficientComminution(CEEC)membersGregLane,ChrisMorleyandMikeDanielofAusencoinAustraliahavereviewedthistopicinsomedetailinapapersubmittedtoIMbyCEECthatlooksatHPGRunitsalreadyinstalledattheArgyle,WhyallaandBoddingtonoperations.
Issuesandopportunitiesthathavearisenincludetheimpactofmoistureandparticlesizeonrollwear;aswellasissuesassociatedwithwetscreening.
Thereviewalsolooksatcircuitdesignissuesinthecontextofoperability,andeco-efficiency.
TheauthorsbelievethatHPGRsarebeingwidelyacknowledgedascomminutiontoolsthatcanbeusedtoreduceoverallcomminutionenergyrequirementswhenusedinanappropriatecircuitconfiguration.
ThisisaconceptthatCEECandAusencoaretryingtoactivelysupportandpromote.
Theexpectationoftheauthorsisthatenthusiasmforthetechnologywillcontinuetowaxandwaneasthetechnical,costandoperatingissuesariseandareovercome.
Thiswillleadtotheestablishmentofthetechnologyforparticularapplications,forexamplerelatingtothescaleandorecharacteristics,thatSAGmillingandotherconventionaltechnologiesarenotparticularlysuitedto.
ThereareseveralHPGRunitsoperatingatAustralianminesites:twoatWhyallaprocessingmagnetiteore;fouratBoddingtonprocessingverycompetentgoldore;andthreeatArgyleDiamondMines.
OtherHPGRunitshavebeeninstalledinAustraliaatSpinifexRidge(molybdenum),Bendigo(gold)andTropicana(gold)amongstothers.
Inaddition,anHPGRhasjustbeeninstalledatCadiawhichistobecommissionedin2012.
SomeearlyAustralianHPGRshadwearissuesafterinstallationbutarecentHPGRoptimisationprogramatCerroVerdeinPeru(ithasfourPolysiusunitswithstuds)onthewearprotectiontyres–improvingstuddesignandgrade–hasresultedinanincreaseofthelifetimetomorethan5,000hwithapotentialtofinallyexceed6,000hwiththenextdesignchange.
OtherhighwearHPGRoperationsareexpectedtobenefitfromthesedevelopments.
ArgyleintroducedHPGRtechnologyin1990tocountertheproblemofincreasedorehardnessofthedeepercompetentunweatheredlamproite(Bondballmillworkindex18kWh/tandBondabrasionindex0.
60)inthemineandalsotoincreasethroughputcapacity.
ThefirstoftwoThyssenKruppPolysiusunits(bothinstalledatArgyleinthe1990s)hasdimensionsof2.
2mdiameterand1mwidthhadtwin1,200kWmotorswithfixedspeeddrives.
Thesecondunitwasinstalledwithtwin1,800kWmotorswithvariablespeeddrives.
Bothunitshavecustomisedbypassrockboxesinplaceoftheconventioncheekplates.
Auniqueon-linegrindingdevicehasbeenadaptedtothebackoftherollstoallowforregulargrindingoftherollsurfacetopreventunacceptablebathtubprofilesonthesegments.
AKHDmachinewasinstalledinthere-crushplantin2002toincreasediamondliberationandrecoverybyreducingtheoverallcrushedparticlesize.
TheKHDunit,withadiameterof1.
7mandawidthof1.
4mwithtwo950kWvariablespeedmotors,isinthequaternarycrushingbuilding.
Thefeedtotherollerpresshasatopsizeof20mmandistruncatedat6mm.
Theproductparticlesizeis80%passing800InternationalMining|MARCH2012COMMINUTIONSchematicofKHDHPGR.
ThecompanyhasnumerousinstallationsincludingArgyleDiamondMinesmm,with36%passing1.
18mm.
Feedrateisaround800t/h.
HPGRshaveallowedBoddingtontotreatthelargelowgradegold-copperprimaryresourcesituatedbeneaththeoxidecap.
TheprimaryoreisacombinationofcompetentdioriteandandesitewithtypicalBondballmillworkindicesof14to17kWh/t.
Boddington'scomminutionflowsheetcomprisesaprimarycrushingsection,closedcircuitsecondaryandtertiarycrushing(withfourPolysiusHPGRsinthetertiarystage),ballmillingandhydrocycloneclassification.
Nominaltreatmentrateis35Mt/y.
Primarycrushingiscarriedoutintwogyratorycrushers.
Thecrushedproduct(nominalP80of150mm)isconveyedtothecoarseorestockpile.
ThesecondarycrushingcircuitcomprisesfiveMetsoMP1000conecrushersinclosedcircuitwithsingledeckscreenswithaperturestoproduceasizeoflessthan50mmfortheHPGR.
ScreenoversizereportstothesecondarycrushersandundersizereportstotheHPGR.
TheBoddingtonHPGRunitsarelarge2,500t/hmachinesmanufacturedbyPolysius.
ThefourPolysiusHPGRseachwitha2.
4mdiameterand1.
65mwidthandfittedwithtwin2.
8MWvariablespeeddrivesfurtherreducethesecondarycrushedoretobelow11mm.
ThefeedtoballmillingiswetscreenedtoremoveHPGRoversize,withthescreenoversizereturningtotheHPGRforfurthercomminution.
Screenundersize(minus11mm)isfedtohydrocyclonesforclassificationwhichproducesafinalgrindsizeof150μm.
WhyallainstalledtwoKppern1.
4mx1.
4mmachineswithHexadursurfaces.
KpperndevelopedHexadur,auniquehighlyabrasionresistantmaterialforwearprotectionforgrindingrollers.
Thenameisderivedfromtheshapeandarrangementofhexagonaltiles.
Themagnetiteoreistreatedtherateof650t/hsplitbetweentwolines.
TheHPGRproductiswetscreenedat3mmandtheoversizereturnedtotheHPGRwhilethefinermaterialissubjectedtowetmagneticseparation.
Non-magneticmaterialsarerejecteddirectlytotailswhiletheconcentrateisre-screenedon700mapertureroughermagneticseparatorscreenswiththeundersizepassingtotheballmillcircuitandtheoversizerecycledtotheHPGR.
Theauthorscomment:"DevelopmentofmodellingandsimulationofHPGRunitprocessesandcircuitshasdevelopedinparallelwiththedescribedplantapplications.
TheprovenunitprocessmodelsarefrequentlyusedinsimulationswhereSAGversusHPGRtrade-offstudieshavebeencompleted.
Thetrade-offstudiesassessthebenefitsofthetechnologywheresecondaryandHPGRcrushingeffectivelyreplacestherelativelyenergyin-efficientSAGmill.
Thesestudiesrequirecomprehensiveorepropertydataaswellastherobustprocessmodelsincludingmodelsthatdescribe,crushing,screeningandballmilling.
"TheJKSimMetcomminutionsoftwaretoolfromtheJuliusKruttschnittMineralResearchCentre(JKMRC)canbeusedforthistypeofanalysis.
Ittypicallyrequiresareviewofhistoricaldata/newtestworkdataandorepropertydata.
ThedataispreparedtosuitanHPGRmodeldescribingthroughput,specificenergyandproductsizedistribution.
JKSimMetcircuitmodelsarethenpreparedincludingre-circulatingloads,screening,ballmillingandsecondarycrushing.
Alternativecircuitoptions/scenariosincludingenergycomparisonswithSAG-basedcircuitscanbeconducted.
TheseimportantaspectsofoverallcircuitdesignaresometimesoverlookedbytheOEMs,accordingtotheauthors,astheprocessguaranteesaregenerallyonlyassociatedwithattainingHPGRthroughputcapacity,whereasthecircuitdesign,includingthesizingoftheballmillreliesonadetaileddescriptionoftheproductsizedistributionresultingfromtheHPGRinclosedcircuitwithascreen.
Thepaperstates:"Atpresent,feedpreparationisofparamountimportanceinmaximisingHPGRavailability.
Thus,effortstosimplifythecurrentlayoutsusedforHPGRbasedcircuitsusingopencircuitsecondarycrushing,reducedemphasisonscreeningandreducecircuitcomplexitypresentarealdilemmaforthevendor,engineerandoperator.
"FuturedirectionsincludethepossibilityofeliminatingtheHPGRproductscreeningstep.
Thetopsizethatcanbefedtotheballmillsdependsonthegrindabilityoftheore.
AsHPGRsfindtheirapplicationwithcompetentores,aballmill'scapabilitytogrindcoarsemillfeedrequiresvalidation.
Thisprocesscanincludeaneco-efficientevaluationoftheoverallcircuitwhencomparedwithconventionalcircuits.
InnovativecomminutioncircuitdesignemployingHPGRshasbeensimplifiedbyCEECinthepastyear,bythepresenceoftheonlinedatasitewww.
ceecthefuture.
org.
CEEChasputcomminutionenergyefficiencyonthetablefordebate;callingonindustryleaderstoaskpertinentquestionswithrespecttoenergyconsumptioninthecomminutionprocess.
Asaconsequence,flowsheetswithnoscreeninghavebeenreconsideredwheretheHPGRoperatesinopencircuitwiththepotentialtorecycleballmillsscatstotheHPGRfeedaftersteelscatremoval.
Ausencoisexploringtheseapproaches.
OneofCEEC'sobjectivesistodisseminatetechnicalinformationrelatingtoeco-efficientcomminutionwiththeoverallaimofimprovingtheefficiencyofmineralprocessingcircuits.
CEECissponsoredbymorethan10oftheworld'sleadingmineralprocessingcompanies–whichinadditiontoAusencoincludesNewcrest,RMEMillReliningSystems,XstrataTechnology,Teck,GoldFields,Gekko,JKTech,Outotec,AMEC,Metso,AMIRA,IndophilResourcesandtheSustainableMineralsInstitute(SMI).
IMspoketoReneKlymowskyatPolysiusaboutthecompany'scurrentrange,notableapplicationsandrecentcontracts.
PolysiusispushingboundarieswithHPGRapplicationsinfinequaternarycrushing,suchasatPTFreeportIndonesia(PTFI)withtwounitsof2mdiameterand1.
5mwidth;intheheapleachingofgoldatTarkwainGhana;inthecomminutionofultra-00InternationalMining|MARCH2012COMMINUTIONFLSmidthengineershavebeendevelopingandtestingHPGRsolutionsandintroducingtheconcepttoitsmineralprocessingofferinghardplatinumoresatMogalakwenainSouthAfrica;and,inpebble-crushingatPenasquitoinMexicoandCadiaHillinAustralia,whichhas2.
4diameterand1.
65mwidthunits.
ThesesamelargemachinesarealsobeingappliedinthecrushingofironoreinthePilbara,WesternAustralia.
Twomoreunitsarescheduledtostart-upsooninmagneticironoreinWesternAustralia.
Infinegrindingapplications,forironorepelletfeed,thewearlivesoftherollshaveexceeded50,000h.
PolysiushasalsojustbeenawardedanorderforeightmoreHPGRs(2.
4mby1.
65m)andeightlargeballmillsforaprojectexpansioninSouthAmerica.
WiththelevelofglobalHPGRinterest,FLSmidthengineershavebeendevelopingandtestingHPGRsolutionsandintroducingtheconcepttoitsmineralprocessingoffering.
Thecompanyfullyadmitsthatinthepast,mineralHPGRswerethe"missinglink"initscomminutionrange.
TherealisedbenefitsofutilisingFLSmidthHPGRtechnologyisthatitcaneasilybebundledwithitsexistingandcomplementarycrushingandgrindingequipment.
Thiswillofferscustomersmultipleoptionswhenitcomestotheirspecificcomminutioncircuitrequirements.
FLSmidthcomments:"Whethercustomersrequirefullflowsheetsorsectionsoftheflowsheet,theHPGRoptimisestheircomminutionresultsbyprovidingenergy-efficiency,high-throughputandmetallurgically-optimisedoretreatmentinbothconcentratorsandhydrometallurgicalplants.
"HPGRsarenotcompletelynewtoFLSmidthasthetechnologyistakenfromthelegacyFLSmidthHighPressureRollPress(HRP)thatoperatessuccessfullyinthecementindustry.
FLSmidthhasbeeninvolvedwithHRPssincetheearly1980swithover90unitssoldtotheindustrythusfar.
However,theseunitsareincementapplications.
Tointroducethissizingtechnologyintothemineralsindustry,theproductnamehasbeenchangedtoHPGRtodistinguishitfromthecementproduct.
Thecompanyalsohighlightstheimportanceoforecalculationsandtestworkincircuitselection.
Itusedtobethecasethatcalculationsalonewereusedtodeterminemachinerequirements.
Oreswerecategorisedandoreaveragesappliedtosetformulas.
However,theseaveragescouldhavea40%to60%variationfromactualthroughputs.
Itisstillusedtogivearoughideabutnotinisolation.
Currentlymostprogressismadeinitiallywithlabtesting.
Withactualsamples,itispossibletoveryaccuratelydeterminethenatureoftheore.
FromthistheOEMcandeterminegapsizesandwearrates.
Thisthentranslatesintomachinesizedeterminationandperformanceguarantees.
Pilottestworkisbecomingmoreandmorepopular.
Withlaboratorytestworkthesupplieriscomfortablewiththeresultsobtained,buttherehavebeensomecaseswheretheactualresultshavenotmatchedlabresults.
Byre-conductingthetestworkitcanbefoundthatthesamplesmayalsovary,thoughasthesamplesweresubmittedbythecustomer,inthiscasetheOEMisnolongeraccountable.
FLSmidthstates:"Thebiggestproblemwehavewiththelaboratorytestworkisthatthemachinesizingandperformanceguaranteehingeson3,000kgofore.
Havingsaidthat,wecan'tmovehundredsoftonnestothelabduetologistics.
Sothenewapproachison-sitemultipletestcampaignswithalargerlabmachine.
"FLSmidthstatesthatthemajorityofHPGRmachineswillbesimilarinsizetothoseusedincurrentcementapplicationswithslightvariationsduetopowerdrawandpressforcerequirements.
ItiscurrentlyenvisagedthatFLSmidthwillbeinthepositiontosupplylargeindustrialmachinesformininginthesecondquarterof2012.
Thegroupstatesthatitalsolookingintodevelopmentoflargerconceptmachines,whichcurrentlyarenotavailablefromcompetitors.
TheHPGRteamiscurrentlyengagedindevelopmentprojectsatbothRioTintoandAngloPlatinumminesites.
TheequipmentattheRioTintoplantiscurrentlyinoperationandtheAngloplantwillberunningthisyear.
FLSmidthwillalsobeinstallingapilotHPGRandWearAnalysisequipmentatitsSaltLakeCityTechnologiescentre.
Thisequipmentwillhelpinsizingindustrialmachinesandevaluatingsurfacewear.
Theequipmentwillbesupportedbyadedicatedteamthatcanalsobedispatchedtositeswherepilottestplantsareinoperation.
XstrataTechnologyhasbeenseeingcontinueddemandforitsIsaMillrange,wellknowntoIMreadersashighintensity,stirredmillsusedinorefinegrinding.
AnIsaMillhasrecentlybeenselectedtobepartoftheRussianCopperCompany's(RCC)MiheevskyprojectinCheylabinsk,Russia.
ThiswillbethefirstIsaMilltobeinstalledinRussia,andwillformpartofthecopperregrindcircuitintheconcentrator,producinghighqualitycopperconcentrate.
TheIsaMillselectedisanM10000unit,andistobesuppliedbyXstrataTechnologywitha3,000kWmotoranddesignedtouseceramicmedia.
TheMiheevskyprojectisanopenpitminetreatingporphyrycopperore,andissettotreat18Mt/ywheninoperation.
Itisscheduledtobecommissionedinlate2013.
RakanRahbani,RegionalManagerforXstrataTechnology,basedinLondon,saidRCCwasseekingInnovativesolutionsforeffectivedevelopmentoftheirlowgradedeposit,andtheIsaMillwasjustoneofarangeoftechnologiestheywereusingtomaximisethecopperrecoveryatthesite.
RakansaidtheprojectwasimportantinestablishingnewmarketsinRussiaandEasternEuropeforthetechnology,whilebuildingontheexistingIsaMillinstallationsinEurope.
TheengineeringforRCC'sIsaMillwillbecarriedoutbyXstrataTechnology'sengineeringteaminVancouver,andwillbeoneofseveralIsaMillprojectsbeingundertakenbytheVancouverteam,includinganM500forTeck'sHighlandValleyCo-MobulkregrindcircuitandTasekoMines'GibraltaroperationusingaM100IsaMillforamolybdenumregrind.
BothminesarelocatedinCanada.
BrakestomediaAsidefromthecrushersandmillsthemselves,aspectsofdeliverysuchasbrakesystems,grindingballsandwearpartscanplayacrucialroleincomminution.
TwiflexandUSdistributorHilliardarecurrentlyworkingonaverylargegrindingmillbrakesystemforNewmont.
Thesystemwillbeinstalledonboth26ftgearlessdrivenballmillsanda42ftgearlessdrivenSAGmillbeingsuppliedbyMetsofortheMinasCongaoxidecopper-goldprojectinPerunearthegroup'sexistingYanacochaoperation.
CongaisPeru'sbiggestminingprojectandwillbeMetso'slargestinstalledSAGmilltodate.
TheTwiflexscopeofsupplyfortheprojectincludestwooffpedestals(brakestations)eachwithfouroffVMS-DPbrakesplushydraulicpowerpacksforeachofthemills.
00InternationalMining|MARCH2012COMMINUTIONTypicallefthandbrakestationdesignedandmanufacturedbyTwiflexTheCongaprojectislocatedapproximately900kmnorthofLimaatanaltitudeof4,100mabovesealevel.
Itis24kmnortheastoftheYanacochaminewherein2008,Twiflexinstalledthebrakesystemonits32ft16.
5MWSAGmill.
CongaisajointventurebetweenNewmontandBuenaventura.
The$8.
4billioncopper-goldprojectisexpectedtostartproductioninlate2014orearly2015.
Forecastedproductionforthefirstfiveyearsisbetween580,000and680,000ozofgoldwith155to235Mlbofcopper.
TheTwiflexbrakesystemisdesignedspecificallyforminegrindingmillinstallationsgivingbothstaticanddynamicbrakingfunctions.
Instaticoperationthebrakesareusedtoholdthemillduringlinerreplacementandgeneralmillmaintenance.
Fordynamicoperationthesystemcanoperateintwomodes,stoppingthemillfromfullspeedinanemergencyorgivinginching/creepingoperationsintheeventofbearinglubricationproblemsorpowerfailures.
Forthefirstacontrolledapplicationofthebrakesisrequiredandforthesecondthebrakesareoperatedquicklytogiveaccuratestopsneededbythemilloperator.
TheTwiflexVMS-DPhasanadjustablebrakingforcefrom590to737kNandisafloatingspring-applied,hydraulically-releasedbrakesuitablefordisc/flangethicknessesfrom117mmto130mm.
Itcanbeusedoninstallationswithadisc/millflangediameterofatleast6.
5mprovidingthebrakingpathisover300mm(thereisnoupperlimitonthedisc/millflangediameter).
Thehydraulicpowerpackoffersanadvancedandversatilebrakecontrolasitallowsbothlocalandremoteoperationforinchingandcreepingdutiesthroughacontrolpanel.
ThebrakingsystemontheConga26ftballmillwillgenerateupto34MNmbrakingtorqueactingona9.
4mdiametermillflangeand51MNmonthe42ftSAGmillwhenactingona14.
2mdiameterflange.
TheVMS-DPcalipersweigh1.
85teachandareabletodelivera940kNclampingforce.
Withafullprocesschargeof1,360t(SAGmill)andoperatingat9rpmthebrakingsystemisabletostopamillinlessthantwoseconds.
Magotteauxprovidessolutionstoindustrieswherecomminutionprocessesareessentialinthemanufacturingoffinishedproducts,includingmines,andregardsitselfasaworldleaderindifferentiatedsolutionsagainstwear.
In2011,MagotteauxwastakenoverbyChile'sSigdoKoppers.
Theoperationwasmeanttoopenupnewmarketpossibilitiesandprogressisbeingmade.
Attheendof2011,itboughttheremaining50%ofitsjoint-ventureinChile,Proacer.
Thetargetistoincreasethegroup'spresenceinthelowchromiumcastgrindingmediamarket.
AttheendofJanuary2012,thecompanyinvestedinthecapitalofSaboChile,aproducerofforgedgrindingmedia,andnowowns55%oftheshares.
ThegrouptoldIM:"Theseacquisitionswilladdanextraproductioncapacityofapproximately95,000ttoourexistingfigure.
TheyallowMagotteauxtoofferthecompleterangeofgrindingmediasolutions–forged,low-chromiumcast,high-chromiumcastandceramicmediainalldiameterrangestosuitalltheircustomers'applications.
"MagotteauxisalsolookingtoexpandinAsiawhereanewproductionunitforverticalmillpartswillsoonstartproductioninThailand.
SinceAugust2011,theOneSteelgrindingmediabusinesshasbeenknowngloballyasMoly-Cop.
Thesechangesarepartofacomprehensivere-brandingprocessfollowingthesuccessfulmergeroftheComsteelbusinessinAustraliawiththerecentlyacquiredMoly-CopbusinessesintheAmericas.
Accordingtothegroup,theformerComsteelGrindingMediaisAustralia'slargestmanufacturerandmarketleaderforthesupplyofgrindingmediausedbymetalliferousandcoalmines.
Comsteelpioneeredthe0.
80%C700BHNballandmorerecentlyhasintroducedthe0.
95%CMiningBallwhichhasbecometheindustrystandardforuseintumblingballmills.
High-performanceSAGmillballsaresuppliedbyComsteelinmanydomesticandexportdestinations.
ThenewMoly-CopAustralianbusinesswillcontinuetoofferacomprehensiverangeofgrindingmediaforwetanddrygrinding,semiautogenous(SAG)andballmillsofallsizes,rodmills,andstirredmillsaswellasmaintainingan"energeticfocusoncontinualmediadevelopment.
"Ballmillgrindingmediaproductsareofferedfrom25mmto94mminarangeofsteelgradestosuitanycomminutionapplication.
SAGmillproductsrangefrom105mmupto150mm,withsteelgradesandhardnesspropertiessuitablymatchedtotheapplication.
InrecentyearsMoly-CophassystematicallyincreasedthesurfacehardnessandwearresistanceofitsSAGmillproductswithoutsacrificingballtoughness.
Moly-CopgrindingmediaisstatisticallysampledfromproductionrunsandroutinelytestedintheOneSteelWaratahNATAAccreditedMetallurgicalLaboratory.
Thelaboratoryisequippedwithmodernspecialisedequipment,specificallyselectedfortestinghighhardnessgrindingmedia.
ItisequippedwithmanualandfullyautomaticVickers,BrinellandRockwellhardnesstestingmachines;fracture-grainsizepress;metallographicsamplepreparationequipmentandmodernstereoscopicandinvertedmetallurgicalmicroscopes.
ThegrouphasaccesstoaScanningElectronMicroscope,afullyequippedandmodernchemicallab,heattreatmentlabanddrop-balltestfacility.
Sizers–morethansizereductionHavingoriginallydesignedanddevelopedthemineralsizer,MMDistheonlymanufacturerwhosewholerangeofequipmentisbasedpurelyonthissizereductiontechnology.
MMD'sfocusonthissingletechnology,togetherwithsustainedinvestment,hasallowedittoextendtherangeofmaterialstowhichsizersare00InternationalMining|MARCH2012COMMINUTIONThemarketforreplacementSAGandballmillmediaishugeglobally.
OneSteelhasconsolidateditspositionwiththeacquisitionofMoly-Copin2011MagotteauxisexpandingrapidlyinSouthAmericaandAsiaapplicableaswellasexpandtheperceivedtechnicalboundariesintheuseofsizers,wellbeyonditsrootsinthecoalindustry.
SomeoftheearlylandmarksinthisdevelopmentprocessandamoveintohardrockwerethefirstsizerunitstobedeliveredtotheuraniumminesinNigerin1982,theUKtinminesin1984andtheSouthAfricandiamondminesin1985.
ButMMDbelievesthatitisinthefieldofIPCCthatsizers,theonlybreakingsystemdesignedformobileinstallationattheoutset,havehadandarehavingthegreatestimpact.
Thesizers'compactdesign;lowprofile;minimumofexternalloadstogetherwithanabilitytohandleawiderangeofmaterialsregardlessofmoisturecontentwithoutanymodificationorlossinefficiency;andtheirabilitytohandlebothoversizedlumpsandcopewithunbreakableinclusionssuchastrampmetalcombinetomakethemidealformountingonmobileinstallations(eithersemiorfullymobile).
Thesizeriscapableofworkinginconjunctionwithshorthaultrucksorbeingloadeddirectlybyshovels,draglinesandevendozers.
Thesizer'shighcapacityandflexibilitymakesthemespeciallysuitableforhighcapacityoperationsinmixedoverburden.
Oneofthegreatestissueswhenconsideringtheuseofasizer,particularlyinhardmaterials,isthatofwearpartreplacement.
Manypotentialusersandconsultantswronglyassumethathavingrelativelysmallwearpartsandwithattritionbeinginvolvedintheirbreakingsystem,thatthisrenderscertainsolutionsunsuitableoruneconomical.
Thisis,however,basedonlargelyunfoundedassumptions.
Thefactisthatthecostofthewearpartsandeventhatoffittingthemcanbecomerelativelyinsignificantwhenbalancedagainstthecostofstoppingproductionformaintenanceorrepairwork.
ThisisofparticularimportanceinhighvolumeIPCCoperationsforoverburden,whereitisnotonlythestoppagetothecrushing/sizingsystemthatisinvolved,butacompleteIPCCsystem.
Thehighlycapitalisednatureofmodernminingmakingitanimperativethatnotonlytheinstallationandoperatingcostsofcrushing/sizingsystem,butthecostofproductionstoppages,bothplannedandunplanned,arefullyconsideredatthefeasibilitystage.
Thesizerhasalowprofileandtheabilitytodispensewithboththeneedforpre-screeningandheavysupportstructures,togetherwithalowerpowerconsumption.
AstudydoneforaleadingcoalcompanybyaSouthAfricanuniversitycomparedthecostofinstallingandoperatingasizertothatofajawcrusherinsimilarconditions.
Bothhandled1,000t/hofROMcoalcontainingsandstone,withamaximumsizedimensionof1,200mm,destinedforacoalhandlingplant.
Theresultshowedthatthetotalinstallationcostofthesizerwaslowerthanthatofthejaw,inspiteofthesizers'initiallyhigherprice.
Evenwhenbasedonthejawcrusherscapacity,thesizeroperatingcostwasconsiderablylower.
Thebenefitsofsizingcanbeevengreateriffulladvantageistakenofthesizer'ssignificantlyhighercapacity,accordingtoMMD.
SimilarconclusionswerearrivedatbyLignitosdeMeirama,intheircomparisonoftherelativecostofusingasizerandagyratoryinoverburdenconsistingofshaleandgranite,thelatteroftenintheformoflargelumps.
Theresultsofextensivetestsshowedthatwhenoperatingat1,500t/htheoperatingcostsofthesizerandthegyratorycrusherwereapproximatelythesame.
However,thesizerprovedcapableofhandlingthefarhighercapacityof4,000t/handthebalanceshiftedsignificantlyinitsfavour.
MMDalsopointsoutthatwhenfrequentreplacementofwearpartsisaconsiderationthesizerhasadistinctadvantageoverconventionalcrusherswhosewearpartscaninvolvetheneedforheavyliftingequipmentandextendedstoppages.
Thesizerusesrelativelysmallindividualwear"caps"thelargerofwhichcanbefittedwithreplaceableplatesandtips,whichcanbechangedindividuallywithoutusingheavytransportorliftingequipment.
Thecompanyadds:"Aspectswhichareoftenforgottenormistakenlysimplyregardedasbeinginconsequentialwhenpreparingcostprojectionsarethesizer'srotatingscreeneffect,whichallowsmaterialtopassthroughitwithoutfurtherdegradationorconsumptionofenergy;thesizespreadorgradationofthematerialthatasizercanhandle;andtheactualcostandperhapsmoreimportantlythetimetakenfortherelocationofthestationinIPCCinstallations.
"Thefactthatthesizersdon'tuseflywheelsandhaveadirectdrivesystemalsomeansthattheyonlyusethepowerrequiredtobreakthematerial,consumingverylittlepowerwhenrunningemptyorhaveverylittlematerialtobreak.
Thisattribute,togethertheirbreakingsystembeingbasedonthelessresistantshearstrengthofrockratherthanitshighercompressivestrength,enablesthemtohavealowerpowerconsumptionthanotherminecrushingsystems.
Anotherbenefitisthattheinwardrotatingunitscentralizematerialonconveyorsallowingfortheirbeinginstalledin-lineorbeingusedtochangethedirectionofconveyors.
Smart…andsmallertagsSmartTagisanRFID-basedtechnologyfromMetsodesignedtoallowtrackingoforefromitssourcethroughblasting,runofmine(ROM)pads,crushers,intermediatestockpilesandfinallyintotheconcentrator.
Assuchitisauniquetoolindeterminingtheoriginofblastedorebeingprocessedintheseriesofsubsequentcomminutionsteps.
Italsoallowsaminetoknowexactlywhenasurveyedblastisbeingprocessed.
ASmartTagRFIDtagtravelsthroughamineandmineralprocessingplantinaseriesofsimplesteps.
Initially,thetagandinsertionlocationisloggedusingahandheldcomputerorPDA,thenitisinsertedintotheore,suchasintoablasthole.
Thetagtravelswiththeorethroughdigging,transportandprocessing,beforebeingdetectedatdetectionlocations(onconveyorbelts),whenthetimeandspecifictagisrecorded.
TheRFIDtagdataisthenloadedintoadatabaseandanalysedasrequired.
00InternationalMining|MARCH2012COMMINUTIONTheMMDsizerhasprovenitselfinmultiplehardrockapplicationsathighthroughputtonnagesToachievethis,theSmartTagsystemrequiresfivemaincomponents.
ThefirstcomponentintheSmartTagsystemisaPDA,whichallowstheinitialRFIDtaginsertionprocesstobecomemoreefficientandaccurate.
EachRFIDtagisaddedtothedatabaseusingoneofthreeoptions;itisassociatedwithaGPScoordinate;itisassociatedwithapredefinedpointsuchasablasthole;oritisassociatedwithanewpoint,whichcanbeaccuratelylocatedlater.
AtpresentthesystemdoesnotallowforhighprecisionGPSbutitcanlocatethenearestpointinaseriesofpredefinedpoints,suchasblastholes,andallowtheusertoassociateRFIDtagswiththesepoints.
Thenextcomponentinthesystem,theantenna,islocatedattheconveyorbelts.
Theantennabothinducesachargeonthetagandalsoreceivesatransmittedsignalbackfromthetag.
Thedesignoftheantennaisdecidedbytwoparameters,whichareitssizeanditsrobustness.
Thesizeoftheantennadictatesthesizeandthestrengthofthefielditradiates.
Forthisapplicationtheareaoffieldstrongenoughtochargethetagshouldbeaslargeaspossible;thereforetheantennausedfortheSmartTagsystemisthelargestavailableforthisfrequencyofRFIDsystem.
AnRFIDreaderthendecodesthesignalfromtheantennaanddeterminestheIDoftheRFIDtagpassingtheantenna.
Laterversionsofthereadersalsohaveauto-tuningcapabilitieswhichensurethatthemaximumpossiblereaddistanceisachievedatalltime.
IntheSmartTagsystemthereaderthentransmitstheIDusingserialcommunications.
Adataloggingorbufferstageimprovesthereliabilityofthesystemsandalsomakesmovablesystemspossible.
ThedataloggerreceivesdatadirectlyfromtheRFIDreader,storestheIDswiththetimetheyweredetectedandmonitorsvitalsystemparameters,suchasthetuningstateoftheantenna.
ThedataloggingstagealsomakesSmartTaglessreliantoncommunicationlinks(suchaswireless)asthedataisstoredatthedetectionpointuntilalinkisestablishedtothesoftwareapplications.
Thecriticalcommunicationslinks,liketheonebetweentheantennaandthereader,areallwiredandveryreliable.
InordertoexpandtheapplicationsofSmartTagthroughandbeyondsecondarycrushing,MetsorecentlyconcludedthataminiRFIDtagwasrequired.
ToincorporatetheminiRFIDtagsintotheSmartTagsystem,Metsofacedtwosignificantchallenges;firstly,thereducedreaddistance,andsecondly,makingtheminitagsrobust.
ByreducingthesizeoftheRFIDtag,thesizeoftheantennainthetagisalsoreduced.
Thesizeoftheantennainthetagisdirectlyproportionaltotheamountofchargethatisinduced,foragivenfieldstrength.
Therefore,thereadrangeofatagwillbereducedasthesizeofthetagisreduced.
Throughinvestigation,the20mmtagswerefoundtohaveaninsufficientreadrangeforthestandardSmartTaginstallation.
Thecompanytrialledtwomethodsforfixingthisissue;onemethodwastousetwoantennaswhilethesecondmethodwastoplacetheantennaclosertotheRFIDtags.
Bothsystemsweretestedatanironoremine.
Bothapproaches,dualantennasorcloserantennadistance,werefoundtohavesimilardetectioncapability.
However,basedpurelyontheeaseofinstallation,asingleantennalocatedunderthebelt,waschosenasthenewstandardinstallationmethod.
ThesecondchallengefacedwhenincorporatingtheminiRFIDtagsintotheSmartTagsystemwashowtoprotectthemsufficientlytosurviveablast.
AmethodpreviouslyusedbyMetsotoachievethiswastoencasethetagsinatwopartepoxy.
Themethodworkswellforprotectingthetags,andalthoughitistimeconsumingandexpensiveitiscurrentlythepreferredmethodforprotectingthetags.
Differentencasingmaterials,suchasreinforcednylon,arestillbeinginvestigated.
TheteamenvisagesthatwiththesuccessfulincorporationoftheminiRFIDtagsintotheSmartTagsystemitwillallowapplicationsforthesystemtobeexpanded.
Thesenewapplicationscouldincludeawideruseintheironoreindustrywheresizeisthecriticalmaterialquality.
MetsoisnowworkingonprovingthereliabilityofthenextsizeofRFIDtags,theevensmallermicroRFIDtag,whichcanpassthrougha10mmmeshscreen.
NewdevelopmentsAsnotedinlastyear'scomminutionreview(IM,November2011,pp42-55),Sandvikrecentlylaunchedtwonewconecrushermodelsthatitbelievesaregivingthemarketevenmoreefficientalternatives.
ThenewCH890andCH895modelshaveanincreasedpowerinput,anewdedicatedtopshelldesignandamainshaftmadefromanewhigh-strengthmaterial.
"Theseimprovementsweremadeinordertopushtheperformanceforproductionofevenfinersizesthanhasbeenpossiblebefore.
Theselatestdesignimprovementsofthecrusherscan–withconsiderablyincreasedsafetymargins–produceafinermillfeedandthusoffloadworkfromthedownstreammillingprocess",saidRobertPicard.
ThedesignphilosophyoftheCHseriesconecrushersistooptimisecrushingforceusingtheASRiandHydrosetsystem.
Asaresult,thepowerdrawiscorrelatedtotheloadandadjustsautomatically.
Furthermore,bycontinuouslymeasuringandcompensatingforcrusherlinerwear,ASRiallowscustomerstofullyutilisecrusherlinersandschedulelinerreplacementstocoincidewithplannedmaintenance.
Sandvikalsooffersitscustomersan800hpanda1,000hpmotorfortheCH890andCH895crushers.
Thepartcommonalitybetweenthetwocrushers,allowsforeasyserviceandsupportwhichshouldfacilitateefficientinventorymanagementandpartsforecasting.
WiththeCHseries,Sandvikclaimstobetheonlymanufacturertooffertheconstantlinerperformancewhichisafunctionofcontinuousmeasuringandcompensationforcrusherlinerwear.
Theautomaticsettingsystem-ASRi-allowscustomerstofullyutilisecrusherlinersandschedulelinerreplacementstocoincidewithplannedmaintenancestops.
TheSandvikCRseriesofhybridrollcrushersareabletostorekineticenergyinthemountedpulleys(beltdrivemodels)andthefastrunningflywheels(directdrivemodels).
Aflywheeloneachrollergivesacrushingpowerthreetofourtimesthatofacrusherwithoutanyflywheel,increasingthecapacityandimprovingthemaximummaterialhardnessbynearly65%,accordingtoSandvik.
Thisenablesthehybridtocrushbiglumpsandmaintainastablecrushingprocessevenduringpeakconditions.
AsaresultSandvikstatesthattheCR810willhandlepeakloadswellwithoutover-dimensioningtheinstalledpower,whichisanadvantagewhenthematerialthatisbeingcrushedcontainshardinclusions.
InitssecondsignificantmillorderinNorthAmerica,BatemanEngineeredTechnologieswasrecentlycontractedbytheprivatelyownedCanadianminingcompany,OntarioGraphiteLtd,tosupplya5.
5mdiameterSAGmilltobeusedintheprimarygrindingcircuitforitsre-openedKearneyMine.
TheorderfortheSAGmill,whichhasaneffectivegrindlengthof2.
74mandwillprocess125t/h,wasplacedinearlyOctober2011.
DeliveryisdueinJuly/August2012andcommissioninginNovember2012.
Thescopeofworkcoversdesign,engineering,manufactureCOMMINUTION00InternationalMining|MARCH2012TheSmartTagconceptfromMetsonowincludesaminiandmicroversiontobettertoexpanditsapplicationsthroughandbeyondsecondarycrushingandsupervisionofinstallationandcommissioning.
Auniquefeatureofthemillistheincorporationofahydraulicdrive,whicheliminatestheneedforthegear,pinionandconventionalgearboxandgearboxmotor,therebysignificantlyreducingmaintenancerequirements.
Inaddition,asthegirthgearisgenerallythelongestleaditeminthemillassembly,replacingthemechanicaldrivewithahydraulicdrivereducesdeliverytime.
Designofthehydraulicdrive,whichwillbefreeissuedbytheclientandtheinterfacebetweenthedriveandthemill,willbeacollaborativeeffortbetweenbothparties.
Sincethisisare-openedminewithanexistingplantfootprint,adesignchallengewillbetofitthedimensionsofthemillaccordingtotheexistingmillfoundations.
DesignandengineeringarebeingcarriedoutatBatemanEngineeredTechnologiesinSouthAfricaandaglobalmanufacturingprocessisbeingutilised.
Variouspartsofthemillarebeingmanufacturedinseveraldifferentcountries,underthesupervisionandstringentqualitycontrolofBatemanEngineeredTechnologies.
Thisstrategyhasworkedwellwithpreviousmillordersaimedatreducingcost,deliverytimeandrisk.
Kearneymine,locatedinKearney,Ontario,isthelargestconfirmedgraphitemineralresourceprospectinNorthAmerica.
Itisalsooneofthelargestindividualdepositsintheworld.
KearneyMinehasbeenundercareandmaintenancesinceitsclosurein1994andispresentlyundergoingarecommissioningprocessthatwillleadtoitre-openingbymid-2012.
Whenreactivated,itisestimatedthatitwillprocessapproximately1Mt/yofore,whileproducing20,000tofnatural,largeflake,highcarbongraphiteconcentrate.
Inacontractawardedearlierin2011,aSAGmillisbeingsuppliedtobeusedintheprimarygrindingcircuitofa9,400t/dayironoreconcentratorintheUSA.
Deliveryofcomponentsisunderwayandinstallationonsitehascommenced.
Commissioningofthemillisexpectedinearly2012.
The8.
53mdiametermillhasaneffectivegrindinglengthof3.
678mandispoweredbya6.
5MWdrive.
Itwillprocess380t/handisdesignedtoworkinconjunctionwithanexistingregrindballmill,toproduceaparticularlyfinegrindofthemagnetiteproduct.
BatemanhastraditionallyservicedthesouthernAfricanmillmarket,butinrecentyearstheindustryhasseenanupswingindemandfromtheinternationalmarket.
Allmilldesignsareproveninthefieldandarebackedbyfiniteelementanalysis.
SAGandAGmillsareavailableupto38ftindiameter,ballmillsupto26ftindiameterandrodmillsupto15ftindiameter.
WellknownconveyorengineeringandconsultinggroupConveyorDynamicshascreatedacompletemine-to-millapproachbylaunchinganewdivision,ComminutionTechnology,tocoverafullspectrumofcomminutionactivities.
ComminutionTechnologyisalsothecreatorofROCKY,describedasa"powerfulnewDiscreteElementModeling(DEM)softwareprogramthatquicklyandaccuratelysimulatesparticleflowwithinaconveyorchute,mill,orothermaterialshandlingsystem.
"ThecompanyiscurrentlyextendingthetechnologywithinROCKYtomodelandtestnewmilldesignconcepts,severalofwhicharenowinvariousstagesofthepatentprocess.
Thetechnologyquicklyandaccuratelysimulatesparticlebehaviorwithinamillsystem.
The"M"versionofROCKYincludesbothperiodicboundariesandparticleenergyspectratohelpusersdesignandevaluatemills,crushers,grinders,andothercomminutionmachines.
Periodicboundariesrecyclebackintothesimulationparticlesleavingaboundary,enablingtheevaluationofanentiremillbysimulatingonlyasmallsliceofit.
Particleenergyspectraallowsforthemeasurementoftheimpactenergyspectrumofthemillboundaries,inturnenablingtheoptimisationofparticlebreakage.
Europe'sleadingaftermarketmanufacturerandsupplierofcrushersparepartsandcrusherservices,CMSCepcor,recentlyorderedanewDoosanPuma700XLMCNCturning/milling/drillingcentreandaDoosanPuma400LBturningcentrefortheirUKengineeringfacility.
ThelargestturningcentreintheDoosanrange,thePuma700XLMisoneofonlytwomachinesintheUKandaddsconsiderableweighttotheirextensivemachinecapabilityintheirengineeringfacility.
ChrisSydenham,TechnicalDirector,commented:"WithanincreaseddemandforqualityUKmanufacturedreplacementcrushersparepartsthesenewmachineswillenhanceourengineeringcapacitytocompletetheUKmanufactureofprecisionmachinedcomponentstosuitprimarygyratorycrushers,conecrushersandjawcrushers,includingrepairstomajorcrushercomponentswithouttheneedtocontractanythirdpartysupplier.
"TheDoosanPuma700XLMisdesignedforhigh-accuracyandheavy-dutymachiningoflarge,heavyandlongcomponentsupto5minlengthandhastheabilitytosupportlargechucks(upto32in).
Withabarworkingdiameter(164mm)capacitycapableofsupportingaworkpieceupto8.
9tbetweenchuckandtailstock,machiningproductivityandflexibilityisfurtherenhancedbythe1,140mmswing-over-bedand1,000mmswing-over-carriagecapabilitieswithlargeturningdiametercapacitiesof900mm.
TheextensiveCMSCepcorengineeringfacilities(CNC,milling,turning,boring,slotting,grinding,drilling,welding,co-ordinatemeasuring&materialtesting)aremanagedbyanexperiencedstaffwithexpertiseinthedesign,manufacture,operationandmaintenanceofcrushingandscreeningplants.
CMSCepcoristheonlyaftermarketsupplierthatalsoincorporatesoneofthemostreputableandlongstandingcrushingplantOEMs,GoodwinBarsby.
IM00InternationalMining|MARCH2012COMMINUTIONThenewDoosanPuma700XLMrecentlyinstalledbyCMSCepcorConveyorDynamicsdivisionComminutionTechnologycreatedROCKY,anewDiscreteElementModeling(DEM)softwareprogramthatquicklyandaccuratelysimulatesparticleflowwithincrushersandmills