英文原文Minehoistingindeepshaftsinthe1sthalfof21stCenturyAlfredCarbogno1Keywords:deepshaft,minehosting,Blairwinder,ropesafetyfactor,drumsizing,skipfactorIntroductionThemineraldepositsareexploitedondeeperanddeeperlevels.Inconnectionwiththis,definitionslike“deeplevel”and“deepshaft”becamemoreandmorepopular.Thesedefinitionsconcernthedepthwherespecialrulesregardinganexcavationdriving,exploitation,rockpressurecontrol,liningconstruction,ventilation,undergroundandverticaltransport,workorganizationandeconomicsapply.Ithaspointedoutthatthe“deeplevel”isaveryrelativedefinitionandshouldbeusedonlywithareferencetoparticularhydro-geological,miningandtechnicalconditionsinamineorcoal-field.Itshouldbealsostrictlydefinedwhatareaof“deeplevel”or“deepshaft”definitionsareconsidered.Itcanbeforexample:-mininggeo-engineering,-technologyofexcavationdriving,-ventilation(temperature).Itisobviousthatthe“deeplevel”definedfromonepointofview,notnecessarilymeansa“deeplevel”inanotherarea.Accordingto5asadeepminewecantreateachmineif:-thedepthishigherthan2300mor-mineraldeposittemperatureishigherthan38C.ItiswellknownthatthemostofdeepminesareinSouthAfrica.Usually,theyaregoldordiamondsmines.Economicdepositsofgold-bearingoreareknowntoexistatdepthsupto5000minanumberofSouthAfricaregions.However,duetothedepthandstructureofthereefinsomeareas,previousmethodsofreachingdeeperreefsusingsub-verticalshaftsystemswouldnotbeeconomicallyviable.Thus,thelocalminingindustryisactivelyinvestigatingnewtechniquesforasingle-liftshaftupto3500mdeepinthenearfutureandprobablyaround5000mafterwards.Whencomparedwiththemaximumlengthofwindcurrentlyinoperationof2500m,itisapparentthatsomesignificantinnovationswillberequired.Themostimportantmatterinthedeepmineistheverticaltransportandtheminehoistingusedintheshaft.Fromtheliterature1-12resultsthatB.M.R.(BlairMulti-Rope)hoistispreferredtobeusedindeepminesinSouthAfrica.Fromtheeconomicpointofview,themostimportantfactorsare:-constructionandparametersofwindingropes(safetyfactor,mainly),-minehoistingdrumscapacity,Thisarticleofinformativecharacterpresentsshortlyabove-mentionedproblemsbasedontheliteraturedata1-12.Especially,thepaperwrittenbyM.E.Greenwayisveryinteresting3.Fromtwotransportsystemsusedinthedeepshaft,sub-verticalandthesingle-liftshaftsystems,thesecondoneiscurrentlypreferred.(Fig.1.)6HoistingInstallationThefrictionhoist(upto2100m),singledrumandthedoubledrum(classicandBlairtypedoubledrum)hoistareusedindeepshaftsinSouthAfrica.DrumwindersDrumwindersaremostwidelyusedinSouthAfricaandprobablyintheworld.Threetypesofwindersfallintothiscategory-Singledrumwinders,-Doubledrumwinders,-Blairmulti-ropewinders(BMR).DoubledrumwindersTwodrumsareusedonasingleshaft,withtheropescoiledinoppositedirectionswiththeconveyancesbalancingeachother.OneorbothdrumsareclutchedtotheshaftenablingtherelativeshaftpositionoftheconveyancestobechangedandpermittingthebalancedhoistingfrommultiplelevelsTheBlairMulti-RopeSystem(BMR)In1957RobertBlairintroducedasystemwherebytheadvantageofthedrumwindercouldbeextendedtotwoormoreropes.Thetwo-ropesystemdevelopedincorporatedatwo-compartmentdrumwitharopepercompartmentandtworopesattachedtoasingleconveyance.Healsodevelopedaropetension-compensatingpulleytobeattachedtotheconveyance.TheDepartmentofMinesallowedthestatutoryfactorofsafetyforhoistingmineralstobe4,275insteadof4,5providedthecapacityfactorineitherropedidnotfallbelowthestatutoryfactorof9.Thisnecessitatedtheuseofsomeformofcompensationtoensureanequitabledistributionofloadbetweenthetworopes.Becausethepulleycompensationislimited,Blairalsodevelopedadevicetodetectthemiscallingonthedrum,asthiscouldcausetheropestomoveatdifferentspeedsandsoaffecttheirloadsharingcapability.Fig.2showsthedepthpayloadcharacteristicsofdoubledrum,BMRandKoepewinders.TheB.M.R.hoistisusedalmostexclusivelyinSouthAfrica,probablybecausetheywereinventedthere,particularlyforthedeepshaftuse.ThereisoneinstallationinEngland.Becauseofthishoistsphysicalcharacteristics,andSouthAfricanminingrulesfavouringitinonerespect,theyareusedmostlyforthedeepshaftmineralhoisting.Thedrumdiametersaresmallerthanthatofanequivalentconventionalhoist,sooneadvantageisthattheyaremoreeasilytakenundergroundforsub-shaftinstallations.ABlairhoistisessentiallyaconventionalhoistwithwiderdrums,eachdrumhavingacentreflangethatenablesittocoiltworopesattachedtoaskipviatwoheadsheaves.Theskipconnectionhasabalancewheel,similartoalargemulti-grooveV-beltsheave,toallowmoderateropelengthchangesduringwinding.Thesheavescanraiseorlowertoequalizeropetensions.TheBlairhoistsphysicaladvantageisthatthedrumdiametercanbesmallerthanusualand,withtworopestohandletheload,eachropecanbemuchsmaller.Thegovernmentminingregulationspermita5%lowersafetyfactoratthesheaveformineralhoistingwithBlairhoists.Thiscameaboutfromademonstrationbythe%permitstheBlairhoiststogoalittledeeperthantheotherdo.Ontheotherhand,theminingregulationsrequireadetachinghookabovethecageformanhoisting.Thebalancewheeldoesnotsuitdetachinghooks,soarope-cuttingdevicewasinventedtocuttheropesoffforasevereoverwind.ThiswastestedsuccessfullybuttheBlairisnotusedformanwindingonaregularbasis.TheB.M.R.hoisthasbeenbuiltinthreegeneralstylessimilartoconventionalhoists.Thethreestylesare(Fig.3and4):ThegearlessB.M.R.hoistatEastDreifonteinlookssimilartoanin-linehoistexceptthatthedrumsarejoinedmechanicallyandtheyarealittleoutoflinewitheachother.Thisisbecauseeachdrumdirectlyfacesitsownsheavesforthebestfleetangle.Thetwohoistmotorsarefedviathyristorrectifier/inverterunitsfromacommon6.6-KVbusbar.Themotorsarethuscoupledelectricallysothattheskipsintheshaftruninbalance,similartoaconventionaldouble-drumhoist.EachmotoralternatesitsactionasaDCgeneratororDCmotor,eitherfeedinginortakingoutenergyfromthesystem.ThegearlessBlaircanberecognizedbytheoffsetdrumsandthefourbrakeunits.Asecondbrakeisalwaysarequirement,each