本科生畢業(yè)設計（論文）題目：陳四樓煤礦1.8Mt/a新井設計礦井底板水突出可能性預測及防治

大學畢業(yè)設計任務書畢業(yè)設計題目：陳四樓煤礦1.8Mt/a新井設計畢業(yè)設計專題題目：礦井底板水突出可能性預測及防治畢業(yè)設計主要內(nèi)容和要求：以實習礦井陳四樓煤礦條件為基礎，完成陳四樓煤礦1.8Mt/a新井設計。主要內(nèi)容包括：礦井概況、礦井工作制度及設計生產(chǎn)能力、井田開拓、首采區(qū)設計、采煤方法、礦井通風系統(tǒng)、礦井運輸提升等。結合煤礦生產(chǎn)前沿及礦井設計情況，撰寫一篇關于礦井底板水突出可能性預測及防治的專題論文。完成2006年《清潔生產(chǎn)雜志》上與采礦有關的科技論文翻譯一篇，題目為“GeotechnicalconsiderationsinminebackfillinginAustralia”，論文4351字符。大學畢業(yè)論文答辯及綜合成績答辯情況提出問題回答問題正確基本正確有一般性錯誤有原則性錯誤沒有回答答辯委員會評語及建議成績：答辯委員會主任簽字：年月日學院領導小組綜合評定成績：學院領導小組負責人：年月日摘要本設計包括三個部分：一般部分、專題部分和翻譯部分。一般部分為陳四樓1.8Mt/a新井設計。陳四樓煤礦位于河南省永城市西北郊區(qū)，交通較為便利。井田傾向（東西）長約4.20km，走向（南北）長約5.90km，井田總面積為24.78km2。主采煤層為2#煤層，平均傾角為10.23°，煤層平均厚度為4.96m。井田地質(zhì)條件較為簡單。井田工業(yè)儲量為177.638Mt，礦井設計可采儲量129.985Mt。該礦井服務年限為55.55a，礦井正常涌水量為894m3/h，最大涌水量為1200m井田為立井兩水平上下山開拓；大采高一次采全厚采煤法；礦井通風方式為中央并列式。礦井年工作日為330d，工作制度為“三八”制。一般部分共包括10章：1.礦區(qū)概述及井田地質(zhì)特征；2.井田境界和儲量；3.礦井工作制度、設計生產(chǎn)能力及服務年限；4.井田開拓；5.準備方式-帶區(qū)巷道布置；6.采煤方法；7.井下運輸；8.礦井提升；9.礦井通風與安全技術；10.礦井基本技術經(jīng)濟指標。專題部分的題目為:礦井底板水突出可能性預測及防治。翻譯部分主要為澳大利亞充填開采土力學因素，英文題目為：GeotechnicalconsiderationsinminebackfillinginAustralia。關鍵字：陳四樓礦井；綜采大采高；中央并列式；底板水突出；充填

ABSTRACTThisdesignincludesofthreeparts:thegeneralpart,specialsubjectpartandtranslatedpart.ThegeneralpartisanewdesignofChensiloumine.Chensilouminelinesinnorth-westofYongchenginHenanprovince.Thetrafficofroadandrailwayisconveniencetothemine.Thewidthoftheminefieldis4.20km,thewidthisabout5.90km，wellfarmlandtotalareais24.78km2.Thetwoisthemaincoalseam,anditsaveragedipangleis10.23degree.Thethicknessofthemineisabout4.96minall.Thefieldgeologicalconditionsaresimple.Theprovedreservesoftheminefieldare177.638Mt.Therecoverablereservesare129.985Mt.Andtheservicelifeofthemineis55.55years.Thenormalflowofthemineis894m3percenthourandthemaxflowofthemineis1200m3percenthour.Themineralwellgasgushesthedeallower,forFieldofverticalshafttransformationontwolevelsdownthemountaindevelopment;Bigminingheightinonetimesthethickcoalmethod;Mineventilationwayasthecentralparatactictype.Theworkingsystem“three-eight”isusedintheChensiloumine.Itproduced330d/a.Thisdesignincludestenchapters:1.Anoutlineoftheminefieldgeology;2.Boundaryandthereservesofmine;3.Theservicelifeandworkingsystemofmine;4.developmentengineeringofcoalfield;5.TheWaystoprepare-arrangetunnelswitharea;6.Themethodusedincoalmining;7.Transportationoftheunderground;8.Theliftingofthemine;9.Theventilationandthesafetyoperationofthemine;10.Thebasiceconomicandtechnicalnorms.Specialsubjectpartsoftopicsis:Theminefloorwaterprominentpossibilitypredictionandpreventionandcontrol.TranslationpartofmaincontentsesisGeotechnicalconsiderationsinminebackfillinginAustralia.Englishtopicis:GeotechnicalconsiderationsinminebackfillinginAustralia.Keywords：ChenSiloumine;Miningwholeheightfullymechanized；Thecentralparatactictype；Bottomwateroutstanding；Backfilling.

TOC\h\z\t"標題1,2,標題3,3,標題,1"目錄1礦區(qū)概述及井田地質(zhì)特征 頁英文原文GeotechnicalconsiderationsinminebackfillinginAustraliaN.Sivakugana,*,R.M.Rankineb,K.J.Rankinea,K.S.RankineaaSchoolofEngineering,JamesCookUniversity,Townsville4811,AustraliabCanningtonMine,BHPBilliton,P.O.Box5874,Townsville4810,AustraliaAbstract:Minebackfillingcanplayasignificantroleintheoveralloperationofamineoperation.IntheAustralianminingindustry,wheresafetyisaprimeconsideration,hydraulicsystemsarethemostcommonbackfillsdeployed.Manyaccidentsreportedathydraulicfillminesworldwidehavemainlybeenattributedtoalackofunderstandingoftheirbehaviourandbarricadebricks.ThispaperdescribesthefindingsfromanextensivelaboratorytestprogrammecarriedoutinAustraliaonmorethan20differenthydraulicfillsandseveralbarricadebricks.Alimiteddescriptionofpastebackfillsisalsoprovided,andtheusefulnessofnumericalmodellingasaninvestigativetoolishighlighted.Keywords:Hydraulicfills;Mining;Backfills;Pastefills;Geotechnical1．IntroductionIntheminingindustry,whenundergroundorebodiesareextracted,verylargevoidsarecreated,whichmustbebackfilled.Thebackfillingstrategiesdeployedoftenmakeuseofthewasterockortailingsthatareconsideredby-productsoftheminingoperation.Thisisaneffectivemeansoftailingdisposalbecauseitnegatestheneedforconstructinglargetailingdamsatthesurface.Thebackfillingofundergroundvoidsalsoimproveslocalandregionalstability,enablingsaferandmoreefficientminingofthesurroundingareas.TheneedforbackfillingisamajorissueinAustralia,where10millioncubicmetresofundergroundvoidsaregeneratedannuallyasaresultofmining[1].Therearetwobasictypesofbackfillingstrategies.Thefirst,uncementedbackfilling,doesnotmakeuseofbindingagentssuchascement,andtheircharacteristicscanbestudiedusingsoilmechanicstheories.Atypicalexampleofuncementedbackfillingistheuseofhydraulicfillsthatareplacedintheformofslurryintotheundergroundvoids.Thesecondcategory,cementedbackfilling,makesuseofasmallpercentageofbindersuchasPortlandcementorablendofPortlandcementwithanotherpozzolansuchasflyash,gypsumorblastfurnaceslag.ThepurposeofthispaperistoanalysethefindingsfromanextensivelaboratorytestprogrammecarriedoutinAustraliaonhydraulicfillsandseveralbarricadebricks.Hydraulicfillsareuncementedtechniques,andareoneofthemostwidelyusedbackfillingstrategiesinAustralia.Morethan20differenthydraulicfills,representingawiderangeofminesinAustralia,werestudiedatJamesCookUniversity(JCU).ThegrainsizerdistributionsforallofthesefillsliewithinanarrowbandasshowninFig.1.Alongwiththem,thegrainsizedistributioncurvesforapastefillandacementedhydraulicfillarealsoshown.Itcanbeseenthatthecementedhydraulicfillfallswithinthesamebandasthehydraulicfill.Theadditionofaverysmallpercentageofcementhasalimitedeffectongrainsizedistribution.Pastefillsgenerallyhaveamuchlargerfinefractionthanhydraulicfillsorcementedhydraulicfills,buthavenegligiblecolloidalfractionfinerthan2μm.Fig.1.Typicalgrainsizedistributioncurvesforhydraulicfills,cementedhydraulicfillsandpastefills.2．HydraulicbackfillsHydraulicfillsaresimplysiltysandsorsandysiltswithoutclayfraction,andareclassifiedasMLorSMundertheUnifiedSoilClassificationSystem.Theclayfractionisremovedthroughaprocessknownasdesliming,wherebytheentirefillmaterialiscirculatedthroughhydrocyclonesandthefinefractionisremovedandthensenttothetailingsdam.Theremaininghydraulicfillfractionisreticulatedintheformofslurrythroughpipelinestoundergroundvoids.Overthepastdecadetherehasbeenasteadyincreaseinthesolidcontentofthehydraulicfillslurryplacedinminesinanattempttoreducethequantityofwaterthatmustbedrainedandincreasetheproportionofsolids.Thechallengeposedbyahighsolidcontentisthatitbecomesdifficulttotransporttheslurrythroughthepipelinesduetorheologicalconsiderations.Currently,solidcontentsof7580%arecommon,althoughevenat75%solidcontent,assumingaspecificgravityof3.00forthesolidgrains,50%ofslurryvolumeiswater.Therefore,thereisopportunityforasubstantialamountofwatertobedrainedfromthehydraulicfillstope.Tocontainthefill,thehorizontalaccessdrivescreatedduringminingaregenerallyblockedbybarricadesconstructedfromspeciallymadeporousbricks(Fig.2).Fig.2.Anidealisedstopewithtwosubleveldrains.Theaccessdrives,whicharemadelargeenoughtopermittheentryofmachineryduringmining,areblockedbythebarricadesduringfilling.Thedrivesareoftenlocatedatmorethanonelevel.Initially,thedriveslocatedatupperlevelsactasexitpointsforthedecantedwater,andalsoserveasdrainswhenthehydraulicfillrisesinthestope.2.1DrainageconsiderationsDrainageisthemostimportantissuethatmustbeconsideredwhendesigninghydraulicfillstopes.Therehavebeenseveralaccidents(namely,trappedminersandmachinery)worldwidecausedbywethydraulicfillrushingthroughhorizontalaccessdrives.Severalreasons,includingpoorqualitybarricadebricks,liquefaction,andpipingwithinthehydraulicfillareattributedtosuchfailures[2].Therefore,permeabilityofthehydraulicfillinthestopeisacriticalparameterinthedesign;continuouseffortismadeduringminingtoensurethatitiskeptaboveathresholdlimitinthevicinityof100mm/h[3].Largerpermeabilityleadstoquickerremovalofwaterfromthestope,thusimprovingthestabilityofthefillcontainedwithinthestope.PermeabilitytestsforminefillsandbarricadebricksarediscussedbyRankineetal.[4].Theconstantheadandfallingheadpermeabilitytestscarriedoutonthehydraulicfillsamplesgivepermeabilityvaluesintherangeof735mm/h.Inspiteofhavingpermeabilityvaluesmuchlessthanthe100mmthresholdsuggestedbyHergetandDeKorompay[3],eachofthesehydraulicfillshasperformedsatisfactorily.Anecdotalevidencesandbackcalculationsusingthemeasuredflowintheminestopessuggestthatthepermeabilityofthehydraulicfillinthemineisoftenlargerthanwhatismeasuredinthelaboratoryundercontrolledconditions.Kuganathan[5]andBradyandBrown[6]proposedpermeabilityvaluesintherangeof3050mm/h,whicharesignificantlylargerthanthosemeasuredinthelaboratoryforsimilarfills.ThesevaluesaremuchlessthanthethresholdlimitprescribedbyHergetandDeKorompay[3],suggestingthatitisaconservativerecommendation.2.2StabilityconsiderationsThestabilityofthehydraulicfillstopeduringandafterthedrainageperioddependsonseveralparametersthatdeterminethestrengthandthestiffnessofthehydraulicfillmass.Theseparameterscanbemeasuredinthelaboratoryusingreconstitutedsamplesorinthemineusinginsitutestingdevices.Duetothedifficultiesandhighcostsassociatedwithcarryingtheinsitutestingrigsintotheundergroundopenings,laboratorytestsarethepreferredalternatives.Strengthandstiffnessaredirectlyrelatedtotherelativedensityofthefill.Whenthehydraulicfillisdenser,therelativedensityandfrictionanglearehigher,andthusthefillismorestable.Ingeotechnicalengineering,thereareseveralempiricalcorrelationsrelatingrelativedensitytotheYoung’smodulusandfrictionangleofagranularsoil.2.2.1MaximumandminimumdrydensitytestsAlargervoidratiodoesnotalwaysmeanaloosergranularsoil.Relativedensityisagoodmeasureofthedensityofthegrainpacking,anddependsonthemaximumandminimumpossiblevoidratiosforthesoilwhilststillmaintainingintergranularcontact.Theminimumvoidratioisgenerallydeterminedbypouringthedrytailingsfromafixedheightsothatthegrainsareplacedataveryloosestate[7].Themaximumvoidratioisgenerallyachievedbysaturatingthetailingsandvibratingthemtoattaindensepacking[8].Thesetwoextremevoidratiosprovidethelowerandupperboundforthevoidratios,and,dependingonwherethecurrentvoidratioofthehydraulicfillis,therelativedensityisdefinedas:(1)LaboratorysedimentationexercisesatJCUlaboratories,duringwhichhydraulicfillingprocessesweresimulated,showedconsistentlythatwhenslurrysettlesunderitsself-weight,therelativedensityofthefillisintherangeof4070%(Fig.3).Fig.3.Relativedensityofthehydraulicfillssedimentedinthelaboratory.SimilarobservationsweremadebyPettiboneandKealy[9]atselectedminesintheUnitedStates.Theinsitumeasurementsshowedrelativedensityvaluesrangingfrom44to66%atfourdifferentmines.Thelaboratoryexercisealsoshowedthatthehydraulicfillslurrysettlestoadrydensity(g/cm3)of0.6timesthespecificgravity(Gs)forawiderangeoftailingswithspecificgravityvaluesrangingfrom2.8to4.4.Drydensity(rd)andvoidratio(e)arerelatedby:(2)Thisimpliesthatallthehydraulicfillssettletoavoidratioof0.67andporosityof40%.Thelaboratorysedimentationexerciseverifiesthis.2.2.2OedometertestsOedometertestsarecarriedoutonhydraulicfillstodeterminetheconstitutivemodellingparametersfortheCamClaymodeleoneoftheconstitutivemodelsthatcanbeadaptedforhydraulicfillswhenanalysedusingnumericalmodellingpackagessuchasFLAC,FLAC3DorABAQUS.Inaddition,oedometertestsareusefulindeterminingtheconstrainedmodulus(D)fromwhich,Young’smodulus(E)canbeestimatedforanassumedvalueofPoisson’sratiousingthefollowingequation.(3)Young’smodulusisacrucialparameterindeformationcalculationsusingmostconstitutivemodels.Theoedometertestsonthehydraulicfillsshowedsignificantcreepsettlementsthattookplaceonthecompletionofconsolidationsettlements.Thishasyettobeverifiedquantitativelyandonafull-scalestope.2.2.3DirectsheartestDirectsheartestsarecarriedouttodeterminethepeakandresidualfrictionangleofthehydraulicfill.Thetestsarecarriedoutonreconstitutedhydraulicfillsrepresentingtheinsitugrainpackinginthestope,whichcanbeatrelativedensitiesof40--70%.Sincethereisnoclayfraction,cohesioniszero.DirectsheartestsconductedatJCUrevealthatthefrictionanglesdeterminedfromdirectsheartestsaresignificantlyhigherthanthosedeterminedforcommongranularsoils.Thiscanbeattributedtotheveryangulargrainsthatresultfromcrushingtherockwaste,whichinterlockmorethanthecommongranularsoils.Theangulargrainscanbeseeninthescanningelectronmicrographsofthehydraulicfillsamples(Fig.4).Fig.4.Scanningelectronmicrographofahydraulicfillsample.2.2.4PlacementpropertytestAplacementpropertytestforhydraulicfillswasproposedbyClark[10].Thisisessentiallyacompactiontest,wherethecompactiveeffortisappliedthrough5minofvibrationonavibratingtable.Porosityattheendofvibrationisplottedagainstthewatercontent.Alternatively,drydensitycanbeplottedagainstwatercontent,asshowninFig.5.Hereaistheaircontent,andthecontoursofa=0,3,10,20and30%areshowninthefigure.Theshadedregioniswherethehydraulicfillcanexistwhilstmaintainingintergranularcontact.Theslurryfollowsasaturationlinewhensettlingunderitsself-weight,withthedensityincreasingwithsomevibratoryloading.Oneofthemainapplicationsoftheplacementpropertytest,asinacompactiontest,istodetermineoptimumwatercontent.InFig.5,theoptimumwatercontentofthefillis14%,withthemaximumdrydensityof2.42t/m3.Thiswatercontentcanalsobeestimatedfromamaximumdrydensitytestandthesaturationlineas12%.Thesecurvesareusefulinassessingthecontractiveordilativebehaviourofhydraulicfillsatvariouswatercontents.Forexample,whenthefillinFig.5issubjectedtovibratoryloading(e.g.,duetoblasting)at14%watercontentandadrydensityof2.0t/m3,itwilldensify,whilstthesamefillat8%watercontentanddrydensityof2.2t/m3willbecomelooser.Fig.5.Placementpropertycurveofahydraulicfillsample.3.BarricadebricksforhydraulicfillminesBarricadefailureinundergroundminingoperationsisaprimarysafetyconcernbecauseofthepotentialconsequencesoffailure.Between1980and1997,11barricadefailureswererecordedatMountIsaMinesinbothhydraulicandcementedhydraulicfills[5].In2000,abarricadefailureattheNormandyBronzewingMineinWesternAustraliaresultedinatriplefatality,andtwopermeablebrickfailureswerereportedlaterthatsameyearasaresultofhydraulicfillcontainmentattheOsborneMineinQueensland[1].Thespecializedbarricadebricksoftenusedforthecontainmentofhydraulicfillinundergroundminesaregenerallyconstructedofamortarcomposedofmixtureofgravel,sand,cementandwaterattheapproximateratioof40:40:5:1,espectively.Fig.6showsaphotographof(a),abarricadebrickand(b),anundergroundcontainmentwallconstructedfrombricks.Traditionally,thewallshavebeenconstructedinaverticalplane,buttherecentindustrytrendhasbeentoincreasewallstrengthbyconstructingtheminacurvedmanner,withtheconvextowardthehydraulicfillasshowninFig.6b.(a)(b)Fig.6.Porousbrickbarricade.(a)Abrick,(b)brickbarricadeunderconstructioninamine.Althoughitisknownwithintheminingindustrythattheporousbricksusedinundergroundbarricadeconstructionarepronetovariabilityinstrengthproperties[5],themanufacturersoftenguaranteeaminimumvalueforuniaxialcompressivestrengthforthebricksintheorderof10MPa[11].Kuganathan[5]andDuffieldetal.[11]havereporteduniaxialcompressivestrengthvaluesfrom5MPatoover26MPa.Aseriesofuniaxialcompressivestrengthtestsundertakenonalargesampleofbrickcoreshavedemonstratedthescatterofresults,butmoreimportantly,havehighlightedadistinctvariationinbrickperformancewhensaturated,asitwouldoccurinthemines.Twoidenticalcylindricalcoreswerecutfrom29porousbarricadebricks.Oneofthebrickcoresfromeachoftheindividualbrickswastesteddry,andtheothercorewastestedafterhavingbeensaturatedforeither7or90days.Thestrengthanddeformationparameters(namely,theuniaxialstrength,Young’smodulus,andtheaxialfailurestrain)forthewetanddrycoresareshowninFigs.7--9.Fig.7.Uniaxialstrengthofdryandwetbricks.Fig.8.Young’smodulusofdryandwetbricks.Fig.9.Axialfailurestrainsofdryandwetbricks.Firstly,theextremescatterbetweenallresultsreiteratesthesignificantdeviationinbrickquality.Fig.7showstheaverageuniaxialcompressivestrengthofdrybrickstofallbetween6and10MPa,whenthebrickmanufacturersguaranteeminimumof10MPa.Itcanalsobeseenfromthisfigurethatthereisadistinctlossofcompressivestrengthasaresultofwettingthebrick.Therewasnosignificantdifferencebetween7and90dayssoaking,implyingthatthestrengthlossoccursimmediatelyuponwetting.Thislossappearstobeintheorderofapproximately25%,whichisnotableconsideringthatbricksaregenerallyexposedtosaturatedconditionswhenplacedunderground,andallmanufacturerstrengthspecificationsarebasedonbricksthataretesteddry.Thestiffnessalsoappearstobereducedbywetting(Fig.8).TheYoung’smodulusofthedrycoresrangedbetween1and3.5MPa.Thelengthoftimethebrickswerewetteddidnothaveasignificantimpactonthemagnitudeofthereductioninstiffness.Thepeakfailureaxialstrainwasnotreducedbywetting(Fig.9).Thecoresingeneralfailedunderanaxialstrainoflessthan1%.Theporousbricksaredesignedtobefreedrainingandtherefore,theirpermeabilityisatleastanorderofmagnitudegreaterthanthatofhydraulicfill.Thebarricadebrickshaveproven,overtime,tosatisfythefree-drainingsituation,andthereductionofpermeabilitythroughmitigationoffineshasnotbeenrecorded.Rankineetal.[4]carriedoutconstantheadandfallingheadpermeabilitytestsonseveralbarricadebricksandreportedpermeabilityvaluesintheorderof3500mm/h,threeordersofmagnitudegreaterthanthepermeabilityofthetailings.4.PastefillLikehydraulicfill,pastefillfallsintothecategoryofthickenedtailings.AconceptualframeworktodescribethickenedtailingsintermsofconcentrationandstrengthisshowninFig.10[12,13].Fig.10.Thickenedtailingscontinuum[13].Pastefilliscomprisedoffullmilltailingswithatypicaleffectivegrainsizeof5mm,mixedwithasmallpercentageofbinder,intheorderof3--6%byweight,andwater.Itisthedensestformofbackfillinthespectrumofthickenedtailingsplacedundergroundasabackfillmaterial.Theacceptanceofpastebackfillasaviablealternativetohydraulicslurryandrockfilldidnottrulyoccuruntilthemid-tolate-1990swiththeconstructionandsuccessfuloperationofseveralpastebackfillsystemsinCanadaandtheBHPBillitonCanningtonMineinAustralia.Sinceadeslimingofthetailingsisnotundertaken,thereisasubstantialfinecontentinpastefills(Fig.1).Ageneric‘‘ruleofthumb’’forthegrainsizedistributionisforaminimumof15%ofthematerialtobefinerthan20mm,whichensuresthatthesurfaceareaofthegrainsislargeenoughtoprovideadequatesurfacetensiontoensurethatthewaterisheldtothesolidparticlesandtoprovideaverythin,permanentlubricatingfilm.Pastefilltypicallyshowsnon-NewtonianeBinghamplasticflowcharacteristics,resultinginplugflow(batchesflowinsolidslugs)characteristicsofthepaste.Asmostoftheearlyresearchperformedonpastefillswasonthetransportationanddepositionofthepaste,themajorityofthedefinitionsofthepastearebasedonitsrheologicalcharacteristics.Table1summarisessomecommoncharacteristicsofthethickenedtailingscontinuumshowninFig.10[14].Hydraulicfillsfallintothethickenedtailingsprofile.Asignificantdifferencetonoteisthatthewatercontentinpastefillisretainedonplacement,throughthelargesurfaceareaofthegrains,eliminatingtheneedforthedesignofdrainageofthefillorbarricades.Thedesignrequirementsforpastefilledstopesarethenreducedtostaticanddynamicstabilityrequirements.Bydesigningthefillmasseswithsufficientstrengthtoensuretheverticalfacesofthebackfilledstopesremainstablethroughouttheminingoftheadjacentstopes,thestaticstabilityrequirementsaresatisfied.Ifthepastebecomesunstable,theadjacentfacesmayrelaxanddisplaceintotheopenstope,causinghighlevelsofdilutionandlossofminingeconomies.Therequiredstrengthofthebackfillsistypicallycalculatedusinganalyticalsolutiontechniques.Morerecently,numericalmodellingsolutionshavebeenusedtodeterminebackfillstabilitythroughouttheentireminingsequence.Thedynamicstabilityofthepastefillstopesisaddressedbydesigningthebackfillmasstoresistliquefactionorotherseismicactivities.Duetotheincreasedresidualmoisturecontentofpaste,thereisanincreasedliquefactionpotentialriskforthepaste.Cloughetal.showedthatcementedsandwithauniaxialcompressivestrengthof100kPawascapableofresistingaseismicactivitymeasuring7.5ontheRichterscale.Thisfigurehasbeenadoptedbytheminingindustryastheminimumdesignstrengthfillforanyfillmass.Thestrengthofthepastesatisfyingthestaticstabilityrequirementsaregenerallyinexcessofdynamicstrengthrequirements.Barricadesaredesignedasundergroundretainingwalls.Thestructuraldesignandconstructionofthewallsmayvaryslightlytothosedesignedforhydraulicfills,duetotheabsenceofdrainagecapabilities.Thebarricadesaredesignedastemporarystructuresinpastefillstopes.Thewallsmustbedesignedtoretaintheliquidmassofthefill,untilsuchtimeasithascuredsufficientlytoactasaplugatthebaseofthestope,thuspreventingtheadditionaldepositedpastefromenteringthemineworkings.Table1MaterialpropertiesforthickenedtailingscontinuumMaterialpropertySlurryThickenedtailingsPasteParticlesizeCoarsefractiononly.Noarticleslessthan20mm.SegregationduringtransportationandorplacementisdependentonlyonthecoarsefractionSomefinesincluded(typically！15%),finescontenttendstomodifybehaviourfromslurryei.e.rheologicalcharacteristicsmoresimilartopaste,howeverdoessegregatewhenboughttorest.SegregationduringtransportationandorplacementisdependentonlyonthecoarsefractionAdditional/mostfines(typically15%(min)>20μmPulpdensity(%)60-7270-7878-82Flowregimes/linevelocitiesCriticalflowvelocity.Tomaintainflowmusthaveturbulentflow(vel<2m/s).Ifvel<2m/ssettlingoccursNewtonianflowCriticalflowvelocity.Tomaintainflowmusthaveturbulentflow(vel<2m/s).Ifvel<2m/spartialsettlingoccursNewtonianflowNocriticalpipelineflowvelocity,i.e.nosettlinginpipeLaminar/plugflowYieldstressNominimumyieldstressNominimumyieldstressMinimumyieldStressPreparationCycloneCycloneendelutriationFilter/centrifugeSegregationinstopeYes/highSlight/partialNoneDrainagefromStopeYesPartial/limitedNone/insignificantFinaldensityLowMedium/highHighSupernatantwaterHighSomeNonePostplacementshrinkageHighInsignificantInsignificantRehabilitationDelayedImmediateImmediatePermeabilityMedium/lowLowVerylow5.NumericalmodellingInlarge-scaleundergroundminingoperations,whereinsitumonitoringofstresses,strains,displacementsandporepressuresisoftenverydifficult,expensiveornotfeasibleatall,theuseofnumericalmodellingtechniquesbecomesextremelyvaluableinunderstandingandpredictingthebehavioursofboththematerialsandthesystemsbeingmodelled.FLACandFLAC3Dareexplicit,finitedifferencesoftwarepackagesspecificallydesignedforsolvinggeotechnicalandminingproblemsintwoandthreedimensions,respectively.TheresearchgroupatJCUhasusedFLAC3Dinsimulatingthefillingoperationsinahydraulicfillandpastefillstopes,studyingthedevelopmentsofstressesanddrainagewithinthefill.Theintentionofthispaperhasnotbeentodetailthefindingsfromthesesimulationsbutrathertohighlightthepotentialthesemodellingtoolshavetodramaticallyincreasetheconfidencewithwhichstopepredictionsmaybemade,ultimatelyleadingtooptimisedmineoperationandsafety.6.ConclusionsCementedbackfillinganduncementedbackfillingarethetwostrategiesusedinminebackfillinginAustralia.Hydraulicfillsandpastefillsareexamplesofuncementedandcementedbackfills,respectively.AseriesoflaboratorytestscarriedoutatJamesCookUniversityonmorethan20differenthydraulicfillsamplessuggestthefollowing:Thehydraulicfill,