陈四楼煤矿1.8Mt-a新井设计-矿井底板水突出可能性预测及防治

本科生毕业设计（论文）题目：陈四楼煤矿1.8Mt/a新井设计矿井底板水突出可能性预测及防治

大学毕业设计任务书毕业设计题目：陈四楼煤矿1.8Mt/a新井设计毕业设计专题题目：矿井底板水突出可能性预测及防治毕业设计主要内容和要求：以实习矿井陈四楼煤矿条件为基础，完成陈四楼煤矿1.8Mt/a新井设计。主要内容包括：矿井概况、矿井工作制度及设计生产能力、井田开拓、首采区设计、采煤方法、矿井通风系统、矿井运输提升等。结合煤矿生产前沿及矿井设计情况，撰写一篇关于矿井底板水突出可能性预测及防治的专题论文。完成2006年《清洁生产杂志》上与采矿有关的科技论文翻译一篇，题目为“GeotechnicalconsiderationsinminebackfillinginAustralia”，论文4351字符。大学毕业论文答辩及综合成绩答辩情况提出问题回答问题正确基本正确有一般性错误有原则性错误没有回答答辩委员会评语及建议成绩：答辩委员会主任签字：年月日学院领导小组综合评定成绩：学院领导小组负责人：年月日摘要本设计包括三个部分：一般部分、专题部分和翻译部分。一般部分为陈四楼1.8Mt/a新井设计。陈四楼煤矿位于河南省永城市西北郊区，交通较为便利。井田倾向（东西）长约4.20km，走向（南北）长约5.90km，井田总面积为24.78km2。主采煤层为2#煤层，平均倾角为10.23°，煤层平均厚度为4.96m。井田地质条件较为简单。井田工业储量为177.638Mt，矿井设计可采储量129.985Mt。该矿井服务年限为55.55a，矿井正常涌水量为894m3/h，最大涌水量为1200m井田为立井两水平上下山开拓；大采高一次采全厚采煤法；矿井通风方式为中央并列式。矿井年工作日为330d，工作制度为“三八”制。一般部分共包括10章：1.矿区概述及井田地质特征；2.井田境界和储量；3.矿井工作制度、设计生产能力及服务年限；4.井田开拓；5.准备方式-带区巷道布置；6.采煤方法；7.井下运输；8.矿井提升；9.矿井通风与安全技术；10.矿井基本技术经济指标。专题部分的题目为:矿井底板水突出可能性预测及防治。翻译部分主要为澳大利亚充填开采土力学因素，英文题目为：GeotechnicalconsiderationsinminebackfillinginAustralia。关键字：陈四楼矿井；综采大采高；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"标题1,2,标题3,3,标题,1"目录1矿区概述及井田地质特征 页英文原文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,