新庄煤矿1.2Mt-a新井设计-浅谈我国煤矿锚杆支护技术发展现状与前景

目录一般部分TOC\o"1-3"\u1矿区概述及井田地质特征 页中国矿业大学2012届本科生毕业设计英文原文TheDevelopmentandApplicationofElectronicTechnologytoIncreaseHealth,Safety,andProductivityintheSouthAfricanCoalMiningIndustryAndrCdeKock,Member,IEEE.andJanW.OberholzerAbstract-SouthAfrica’scoalminingindustryisofvitaleconomicimportance.Thispaperdescribessomeofthemajorelectronicachievementswithinthatindustryoverthepasttento15years.Basicdesigncriteriaformulatedforsystemstobeusedundergroundisdiscussed.Theexperiencegainedwiththeimplementationofthesystems,especiallythehumanfactor,isexamined.Futuredirectionstobefollowed’bysomeoftheresearchprogramsarepresented.Keywords-Coalmining,health,productivity,remotecontrol,safetyIINTRODUCTIONCoalplaysasignificantroleintheSouthAfricaneconomyandissecondonlytogoldinearningforeignexchange.Asaresultofalackofalternativeenergysourcessuchasoilandlargescalehydroelectricpower,coalisthecountry’smajorenergysource.Bysupplying88%ofthecommercialenergyrequirements,coalisalso,therefore,amajorcontributortoeconomicgrowthandindustrialization.Ofthe182milliontonsproducedin1993,131.9milliontons(72%)wereuseddomestically[l].Escom’scoal-firedpowerstations,togetherwithafewlocalutilities,consumemorethan75milliontonsannually.Sasol,theonlysuccessfulcommercialoil-from-coalproducerintheworld,consumed39milliontonsin1988,makingitthesecondmostimportantdomesticuser.OthermajorusersincludeIscor’smetallurgicalplants,thecementindustry,andthelargemunicipalities.Approximately90%ofthetotalsaleablecoalisproducedfromtheWitban/Highveltcoalfields,twoofSouthAfrica’s19coalfields.In1989,SouthAfrica’seconomicallyrecoverablecoalreserves,estimatedat58billiontons,rankedSouthAfricasecondamongWesternnationsandfourthinglobalterms[2].MostofSouthAfrica’scoalisofabituminousthermalgrade,approximately2.0%isanthracitic,andsome1.6%isofmetallurgicalquality.Overthepastfewyears,therehasbeenagrowthindemandforsteamcoalcoupledwithasupplyshortagecausedbyproduction,weather,andlaborproblemsthataffectedmoststeamcoalexportersinthelate1980’s.ThesemarketconditionswerebeneficialtotheSouthAfricancoalproducers.Ofthe182milliontonsofcoalproducedin1993,about51milliontons(28%oftheannualproduction)wereexported,earningsomeR4.5billionofforeignrevenue.SouthAfricanminestendtoberelativelylargeand,consequently,havenumerousundergroundsections.Itis,therefore,notunusualforasmanyastenundergroundsectionstobeservedbyasingleshaft.Anindividualminewillusuallybededicatedtosupplyaspecificpowerstationorprivatecontract.Theserequirements,inturn,dictatetheoverallproductionrates.Undernormalconditionstheseremainfairlystatic.Theemphasisofaproductivityincreaseisthusnotnecessarilytoincreasetheoutputfromthemine,butrathertodecreasetheresourcesrequiredtoextractthecoal.This,inturn,leadstoadecreaseinthenumberofemployeesrequiredandis,therefore,metwithresistancefromtheworkforce.AnotheraspectoftheSouthAfricanminesisthediversityofminingmethodsemployed.Threeminingmethodsareusedintheextractionofthecoal.Theyarebordandpillar,pillarextraction,andlongwalls.Withbordandpillarandpillarextraction,twominingmethodsareused.Thefirstisconventionaldrillandblast,andthesecondutilizescontinuousminerstoextractthecoal.AscanbeseenfromFig.1[3],therewasamajorincreaseintheproductionfromtheminesbetween1970and1990.Thiswasadirectresultofasignificantincreaseinthemechanizationofthecoalmines,withtheintroductionofcontinuousminersandlongwalls.Althoughthenumberoflongwallfacesincreasedupto1990,thetrendhasbeenreversedinlateryears,withmoreattentionbeinggiventocontinuousminerstoopingandribpillarmining.Themainmotivationforthistrendisthatcontinuousminersectionsaremoreflexiblewithregardtoundergroundgeologicaldisturbancesinthecoalseam.Anaddedadvantageisthatthecapitalexpenditurepercoalproductionunitissignificantlylower.ThisledtheChamberofMinesResearchOrganization[COMRO,nowCounselforScientificandIndustrialResearch(CSIR):MiningTechnology)]tofocusmostofitsresearchoncontinuousminers.Duringthepastfewyears,theincidenceoflabordisputeshasincreasedconsiderably.Thishasforcedmanagementtospendalargeamountoftimeandeffortinresolvinglaborrelatedproblems.Wagedemandshavebeenthemajorcontributortotheescalationinproductioncosts,whileincreasesinproductivityhaveremainedlow.Theworkforceis,however,beginningtoappreciatetheneedforlaborstabilityandjobsecurity.Fig.1Productionperminingmethod=2\*ROMANIIBACKGROUDDuringthe1970’s,COMROspentmuchtimeandresourcesonevaluatingcontinuousminers.ItwasgenerallyfoundthatthecoalintheSouthAfricancollierieswasharderandmoreabrasivethanthecoalinthecountriesfromwherethecontinuousminerswereoriginallyimported.Researchwas,therefore,aimedatimprovingtheproductionratesfromthemachinesbydevelopingamoreefficientcuttingprocess.Productionfiguresforthecontinuousminerswererecordedandaccumulatedinadatabase.Usingthisdatabase,Pieterse[4]establishedthattherewasonlyasmallchangeintheoverallperformanceofthecontinuousminers,althoughasignificantimprovementinthecuttingprocesshadbeenbroughtaboutbynewcuttingcyclesandlocallydevelopedcontinuousminers.In1985,Oberholzer[5],usingthedatabase,concludedthattheavailabilityofacontinuousminerforcuttingwasfairlyhigh.TheemphasisofCOMRO’sresearchthenshiftedfrommachinecapacitytoevaluatingthemannerinwhichthecontinuousminerwasutilized.Followingthis,OberholzerandThorpe[6]investigatedthecuttingratesofcontinuousminers.Theyfoundthatthecuttingrateofacontinuousminervariedsignificantly,inspiteofthefactthattheconditionswithindifferentsections,includingtrammingdistances,werenearlyidentical.Theyfurtherfoundthatthe“unproductive”phasewithinthecuttingcyclecouldbeashighas43%ofthetotalcuttingtime.Thisconfirmedtheassumptionthatproductionfromacontinuousminerwasinfluencedmorebyexternalfactorsincludedintheoverallminingprocess,asopposedtoitscoalcuttingability.Thiswasmainlyattributedtothemachineoperator’sability,experience,andthetechniquesheused.Thesefindingsthenformedthebasisofsomeoftheresearchworkthatwasconductedfrom1985.A.DesignConsiderationsItwasdecidedthattheprimaryaimofallsystemsthatweretobedevelopedwastoimprovetheproductivityandworkingconditionsoftheoperatorattheface,withoutremovingtheoperatorfromtheface.Thefollowingwerethensetasadditionalcriteriathathadtobemetthroughthedesignandimplementationofelectronicequipmentintheprogram.NeedsDriven:Researchundertakenhastobeneeds,andnottechnology,driven.Therefore,thestartingpointofprojectswastofindordeveloptechnologythataddressedaspecificneedofthecoalminingindustryandnottofindapplicationsforexistingtechnology.IntrinsicSafety:AllelectronicorelectricsystemshavetobedesignedtoconformtoSouthAfricanBureauofStandards(SABS)standardssetoutforintrinsicallysafeorflameproofapparatus,inordertoeliminateanypossibilityofmethaneignition.Thisledtothedevelopmentofaninexpensiveandeasywayofmanufacturingintrinsicallysafebatterypacks[7].UniversalFitting:Thesystemhadtoberetrofitable,makingitpossibletofitthesystemtoallthedifferenttypesofnewandexistingequipmentusedinSouthAfricancoalmines.Thesystemcouldthen,forexample,betransferredbetweencontinuousminersindifferentsectionsofthemine.Mine-Proof:Allthecomponentsofasystemhavetobeprotectedagainstcoal,rock,dust,water,andmoisturepenetrationintoelectric/electronicenclosuresandcables.Allpartshavetoberobustenoughtoresistmechanicalimpactscausedbyfallingmaterialsormovablepartsoftheequipment.MaintenanceandRepair:Thedesignedsystemsshouldbesimpleinthattheydonotrequirehighlyqualifiedpersonneltomaintainthemintheundergroundsituation.Itwasthereforedecidedtouseamodularapproachwherecircuitboardscouldbereplacedbyunskilledpersonnel.Thefaultymodulescouldthenbebroughttothesurfacewheretheywouldbecheckedandrepaired.Anyinstallation,maintenance,andrepairofsystemsmustnotpresentanyrestrictionIOnormalminingoperations.Acceptability:Itwasimperativeforthesuccessofsystemsthattheoperatorand/orotherpersonnelinvolvedintheoperationofequipmentacceptthemandnotfeelthreatenedbytheirpresence.=3\*ROMANIIITECHNOLOGYDEVELOPMENTSomeofthemainthrustareasthatwereinvestigatedduringthepasttenyearswerethefollowing.A.CoalInterfaceDetection(CID)Optimalutilizationofavailablereservesrequireaminetoremoveasmuchoftheinsitucoalaspossible.Inordertoachievethis,partofthecontinuousmineroperator’sgoalistocutascloseaspossibletothetopofthecoalseam.Toassisttheoperatorinachievingthis,twoofthemostpromisingtechniquesthatwereinvestigatedwerenaturalgammaradiationandvibrationanalysis.(1)NaturalGammaRadiation:Followingthesuccessofusingnaturalgammaradiationforthedetectionofthecoal-stoneinterfaceintheUnitedKingdom,COMROin1986investigatedtheapplicationofthesamemethodinSouthAfrica.Theoverlayingstrataofthecoalseamsusuallycompriseclays,silts,ormudstones.Mixedinwiththesestrataaresomenaturallyoccurringradioactiveelements,themostcommonbeingpotassium(K40),thorium(Th232),anduranium(U235).Theprincipleofthesystemwastotreattheoverlayingstrataasagammasourceandtheconnectinglayerofcoalasagammaabsorbent.Thethicknessoftheabsorbentwouldthenbedeterminedbytheamountofattenuationitimposedonthegammaraysemittedfromtheoverlayingstrata.Theinvestigationcovered20collieriesusinganinstrumentthathadalreadybeenprovensuccessfulinBritishcollieries.FromtheirfindingsitwasconcludedthattheuseofsuchasystemwasnotfeasibleintheSouthAfricancoalmines.Itwasfoundthatthepresenceofuraniumwithinthecoalseamtendedtocanceltheexpectedattenuationofthegammaraysbythecoalincontactwiththeoverlayingstrata.(2)VibrationAnalysis:ResearchcarriedoutatCOMROusingvibrationanalysiswasnotaimedatdeterminingtheroofcoalinterface,butatinvestigatingtheconditionofthecontinuousminer.Theintentionwastoinvestigatethedifferentvibrationsproducedbythecontinuousminer.Fromthevibrationspectrumitwashopedtoestablishacharacteristicvibration“fingerprint”forthedifferentactivitiesperformedbythecontinuousminer.Itwasalsoenvisagedthatitmightbepossibletofindaroof/coalinterface“fingerprint”thatwouldindicatethethicknessofthatinterface.Asastartingpoint,itwasdecidedtoinvestigatetheconditionofthepicksonthecutterdrum.Thevibrationspectrumofnewpickswascomparedwiththatofwornpicks.Initialresultsindicatedthatitmightbepossibletodeterminetheconditionofthepicks.Agreatdealofrefinementwould,however,havetobemadebeforethesystemcouldbeusedonacontinuousminer.However,asignificantpotentialhadbeenindicated.AsaresultoflimitedresourcesandanevaluationofCID,itwasdecidednottodofundamentalresearchonCID,andresearchinthisfieldwasdiscontinued.B.ProductivityThestudybyOberholzerandThorpe[6]showedthattheindividualcontinuousmineroperatorhasamajorinfluenceonthecuttingratesofthecontinuousminer.Variationsinthejudgmentofdifferentoperatorsappearedtoberesponsibleforthedifferentoutputrates.Thesevariations,attributedtothehumanfactor,directlyaffectthecontrolofthesumpingandshearingprocess,aswellasthetransportationofthecoal.Thetimelossesthatcanbeattributedtotheoperator’sinfluencetendtobesmall,butaresignificantwhenviewedinperspective.Managementtendstofocusmoreattentiononfactorscausinglargetimelossesandignoretheshort,seeminglyinsignificant,timelosses.Thesmalltimelossesare,however,occurringcontinuously,andtheircumulativeeffecthasamajorinfluenceonthetotalproductionlossofthesection.Themostimportantofthesedelaysareduetothefollowing:·poorhorizoncontrolleadingtoprematurepickdamage,coalcontamination,andanexcessiveamountoftimespentonlowcuttingratesduringroofandfloortrimming;·failuretocontrolthesumpingdepthandthesubsequentinabilitytocutcoalattheoptimumrateandtosynchronizecoalcuttingandcoaltransportation;·lowboomliftratesduetooperatorcautionandtheinabilitytoidentifythecorrectsumpingheightduetopoorvisibility.Toaddresstheproblemsidentifiedintheproductionofcoalusingacontinuousminer,asdiscussedabove,acontrolsystemwasdesigned[7].The“total”controlsystemconsistsofahorizoncontrolsystem,anadvancecontrolsystem,thecontinuousmineroperator,themachinecontrols,andtherequiredhorizon.Byusingonlythevisualindicatorsofthehorizonandadvancecontrolsystem,theoperatorwillcomparetheactualpositionofthecutterheadwiththatoftherequiredposition.Ifthereisadifferencebetweenthetwopositions,theoperatorwillclosetheloopbyactivatingthemachinecontrolsandmovetheboomuntiltheactualandrequiredpositionarethesame.Withthisapproach,theoperatorremainsthecruciallinkinthesystem,asheretainsoverallcontrol.Thetwoproblemsaddressedbythehorizoncontrolaretheboomlifttimesandcontroloftheroofandfloorhorizontowhichthecoalseamiscut.Theboomlifttimeisdependentontheabilityoftheoperatortoliftthecuttingboomatmaximumspeeduntilthecutterheadisasclosetotherequiredpositionaspossible.Similarly,thelocationofthehorizonisdependentontheabilityoftheoperatortostopthecuttingboomatthecorrectroofandfloorpositionseverytime.Withoutthehorizoncontrolsystem,theoperator“feels”fortherequiredposition.Thisisdonebycautiouslyliftingtheboominsmallincrementswhenitisclosetothedesiredposition.Thesepracticesresultinincreasedboomlifttimesandtheunevencuttingofthehorizon.Theothersectionactivityonwhichthecontinuousmineroperatorhasamajorinfluenceisthesynchronizationofcoalcuttingandtransportationofthecoalinthesection.Duringnormaloperatingconditionsthereisalwaysashuttlecarwaitingtobeloadedatthecontinuousminer.Ifthecontinuousminerfillstheshuttlecarbeforethecutiscomplete,ithastowaitwhiletheshuttlecarschange,andtheprocessoffillingonecarwithonecutlosessynchronism.Thisproblemwasaddressedbytheadvancecontrol,wherethedepthofsumpiscontrolledtoallowashuttlecartobefilledwithonesumpandshearcycle.Variousmethodsofdeterminingthesumpingdepthwereinvestigated[3],[7].Eachofthemethodsisbasedonusingadifferentapproachforestablishingareferencefromwhichtomeasuretheforwardmovementofthecontinuousminer.Thethreereferenceplanesconsideredwere:·thecoalfaceinfrontofthecontinuousminer;·atargetfixedtotheroofbehindthecontinuousminer;·theroofabovethecontinuousminer.Duringthequantificationoftheadvantagesofthesystems,itwasfoundtobepossibletocutsmoothfloorandroofhorizons.Thecycletimeofthecuttingprocesswasimprovedby36%byusingthehorizoncontrolsystem.C.CommunicationChannelsInadditiontothenormaltwo-wiresystemsfoundunderground,channelsforthetransmissionofdatawereinvestigated[8].Thechannelswereinfrared,opticalfiber,radio,andpowerlinecarrier.(1)Infrared:Withoutspecialopticaldevices,inthepresenceofcoaldust(notexceedingalevelof100mg/m3)andwithatotalLEDradiationpowerof200mW,reliabletransmissiondistancesof3040mwereachieved.Theadditionofasinglelensateitherthetransmissionorreceivingendincreasedthedistancetobetween60-80m.Duetothedefusingofinfraredradiationonroadandpillarsurfaces,andscatteringfromcoal,rock,ordustparticles,communicationispossibleevenwithoutadirectpropagationpathbetweentheinfraredtransmitterandreceiver.Amathematicalmodelwasdevelopedtodeterminethefullpowerofinfraredradiationincidentonthephotosensitivesurfaceofthephotoreceiver.(2)PowerlineCarrier:Theprincipleofthischannelistheuseofthecontinuousminer,shuttlecar,orroofbolterpowertrailingcableasacommunicationmedium.Themethodincorporatesclip-oninductiveantennaewhichcanbeclampedaroundbothsidesofatrailingpowercableatthemachineandtheswitchgear.Thisisthemostattractivemethodasitprovidesquick,in-mineinstallationofacommunicationchannel.Themaindifferencebetweenthisandaconventionalradiosystemistheantennasystemandpropagationmedium.Testswerecarriedoutwhereasignalwascoupledintothetrailingcableofacontinuousminer.Theresultshaveshownthatcommunicationispossibleoveradistanceof200m.ThesystemisbasedonanonintrusivemethodofcouplingthatwasdevelopedbyCOMRO.(3)OpticalFibers:Opticalfibersarefabricatedfrommaterialswhichareelectricalinsulators.Thismakesthemidealforcommunicationuseinanelectricallyhazardousenvironment,astheycannotcauseanyarcingorsparkhazard.Modulationofseveralgigahertzoveradistanceofafewkilometerswithouttheinterventionofelectronics(repeaters)ispossible.Theinformation-carryingcapacityandbandwidthofopticalfibersystemsisfarsuperiortothebestcoppercablesystemsorwide-bandradiosystems.Withtheadvantagesofferedbyopticalfibersystems,itisforeseenthatmostcopperwiresystemswilleventuallybereplacedwithopticalfibersystems.Forthesuccessfulimplementationofopticalfiberasachannel,theopticalfiberhastobemanufacturedasanintegralpartofthepowercableofequipment.Asthistypeofcableisbecomingavailable,itisopeningawholenewfieldofavailablechannelsthatcanbeusedfortransmittingvastamountsofinformation.(4)Radio:Radiocommunicationchannelshavesomeundergroundminingapplicationsforspeechanddatacommunication.Withoutsomecasualwaveguide,suchascables,rails,steelropes,andpipes,aradiochannelcannotprovidelongdistanceout-of-sightcommunication.Inmostcases,aleakyfeederhastobeinstalledthroughouttheminetoprovidereliablelinksbetweenportableandmobileradiostationsorterminals.Radiowavesarehighlysusceptibletoelectromagneticfieldsgeneratedbythepowercablesoftheminingequipmentinthesection.Someofthepreviouslymentionedsystemsaremoresuitablefortransmissionofdatathroughoutamine.=4\*ROMANIVRESULTSEventhoughalargeamountoftimeandeffortwasspentondevisinganimplementationstrategy,itwasnotpossibletoimplementthesystemsinaminebeyondtheprototypestage.Withtheimplementationofthehorizoncontrolsystem,problemswereencounteredfromalllevelsofstaffonthemines.Inthesection,thesystemsweresabotagedinvariousways.Moreexcusesforwhythesystemcouldnotworkwereforwardedthanreasonsofwhyitcouldwork.Thesystemwasblamedforproductionlosses,evenafteritwasproventhatitincreasedproductionby36%.Fromseniormanagement,thesystemswereoftenreferredtoas“starwars”technologyandtooadvancedforthemines.Theresultoftheseattitudeswasthatwhentheoriginalsupportfortheprojectceased,nusponsorscouldbefoundtofundfurtherdevelopmentofhesystems.Themainexplanationpresentedwasthattheworkhadnoimmediateapplication.Otherargumentspresentedwerethatthereweremorepressingproblemstocontendwith,suchasminesclosingdownduetocostincreasesandworkers’exposuretodust.Thiswasnotwithstandingthefactthatallinvolvedwiththeprojectagreedthatexcellentworkhadbeendone.Therealvalueofthepastresearchlies,however,notintheactualworkthatwasperformed.Theelectronicsused,aswellasthehardwaresystemsdeveloped,havebecomedated.Theessentialoutputfromthispastresearchistheexperiencegainedregardingtheuseofsuchsystemsunderground.Thestrongresistancethatwasexperiencedwiththeintroductionofthesystemscanbeattributedtotwomainreasons,oneclearlyevidentandtheotherlessapparent.Theevidentreasonwasthattheworkersfeltthreatenedbythesystems.Apartfromthenormalresistancetochange,especiallytoasystemasadvancedasthis,theworkerssawtheintroductionofthesesystemsaspreliminarytothemlosingtheirjobs.Thisperceptionledtoactsofsabotageandpassiveresistance.Thiswasnotwithstandingthefactthatithadbeenstressedthatthesystemwastomaketheoperator’sworkeasier.Thelessapparentreasonwasthatthesystemwasnotcompatiblewiththemannerinwhichthesectionwasoperated.Itrequiredtheminetomakechanges,albeitnegligiblysmallinsomecases,tothemodeofoperation.Thismadetheworkersfeelthattheywerebeingrunbytheinstalledsystem,ratherthanthemusingthesystemtotheiradvantage.Therealitywasthattheelectronicsandsoftwareweresufficientlysophisticatedtoenableasystemtobedevisedthatwouldsatisfythesetobjectivesandstillaccommodatethewishesofminestaff.Whenchangestothesystemweremadethatfullyaccommodatedtheoperator’swishes,acceptanceofthesystemincreaseddramatically.Thesamesyndromeof“feelinginchargeofthesystem”wasalsodisplayedbyvariousmanagementstaff.Initiallyantagonistic,thesepeopleatalaterstagestartedworkondevelopingsimilarsystems,butoftheirowndesign.Thereisaseeminglyinherenttendencyofpeopletospendmoretimeondevelopingsystemsthatsuittheirneeds,ratherthanspendasignificantlylessamountoftimetoadapttheirneedstoadifferentformat,butonethatsuitstheestablishedsystem.Theauthorsbelievethatthereasonforthisliesnotintheresistancetochange,norintheinabilityorreluctancetousetheoutputsfromthesystem,butratherinthedesireofthepersonusingittocontrol,ratherthanbecontrolledby,thesystem.=4\*ROMANVFUTUREDIRECTIONSA.RemoteControlTheneedforbettersafetyandhealthstandardshasresultedinarenewedinterestinradioremotecontrolforcontinuousminers.Newlegislationandtherealizationthattheoperatorcouldbemovedtofreshairhavesparkedthisrenewedinterest.Thepresentresearch[9]doneinthisareahasconfirmedresultsobtainedintheU.S.[l0]withrespecttothepositionoftheoperator.Irrespectiveoftherulesandregulations,theoperatorinvariablymovesintomoredangerousareaswhenusingaremotecontrolsystem.Oneofthepresentareasofinvestigationisfindingmeansofkeepingtheoperatorinasafepositionatalltimeswhenusingaremotecontrol.AremotecontrolsystemisunderdevelopmentthatwilladdresstheneedsoftheSouthAfricancoalminingindustry.Theseneedsweredeterminedbyanintensiveinvestigationwheretheopinionsofallconcerned,fromtheoperatortotheminemanagement,wereobtained.Theseopinionswerethenusedtodrawuptherequirementsofanidealradioremotecontrolsystem.Oneofthemostimportantrequirementsthatwasidentifiedwasthatthesystemmusthavetwo-waycommunicationbetweentheoperatorandthecontinuousminer.Thisistoprovidehimwithinformationaboutthecontinuousmineritself.Bycombiningthecontrolsystemandtheelectrohydraulicsofthemachine,itispossibletosetinterlockswhichwillcutouttheoperationofthemachineifunsafeconditionsarise.Withthisapproach,thesystemwillbeanintegralpartofthecontinuousminerandwillforcetheoperatorstofollowsaferoperatingpractices.Withthenewsystem,theshuttlecaroperatorwillcontroltheoperationoftheloadingboomofthecontinuousminer,allowingthecontinuousmineroperatortoconcentrateonthecuttingofcoal.Itisenvisagedthatthefirstsystemwillbeinstalledonacontinuousminertowardtheendof1995.B.EnvironmentalHealthandSafetyIntheenvironmentalarea,electronicshavebeenusedforalongtime:forexample,theuseofmethanometerstotestforthepresenceofmethanegas.Atpresent,theentireSouthAfricancoalminingindustryuseselectronicinstruments,withflamesafetylampsnowbeingusedasgiftsandornaments.Theuseoftelemetry,andtheaccompanyingsoftwaretoanalyzethedata,whichcanconsistofreadingstakenatintervalsofaslittleasfourseconds,hasshedsignificantlightnotonlyonthecharacteristicsoftheoccurrenceofdust,butalsoonthewayitreactswithvariousparametersinthesection.Theuseofsuchinstrumentshasmadeitpossibletounderstandthenatureofthetimeandspacedistributionofrepirableandairbornedusttoalevelwhichwouldhavebeenimpossiblewiththemorecommongravimetricsamplers.Inasimilarway,multiheadmethanometerscoupledtodataloggershavebeenusedtoquantifythetimeandspatialdistributionofmethaneinareasaroundthecontinuousminingmachines.Presently,readingsaretakenonandaroundcontinuousminersatsixdifferentlocationssimultaneously.Thereadingsaretakenatintervalsof10sandforperiodsrangingupto10h.Thiswillthengiveanindicationofthedistributionofmethanewhilecoalisproduced.Byincorporatingtheinformationobtainedattheworkingfacewithinformationaboutairflowinthesection,atotalenvironmentalpictureoftheconditionsinthesectioncanbegenerated.ThiswillthenaddressaneedthathasbeenlongoutstandinginSouthAfrica,namely,reducingtheinfluenceofhumanerror,theeffectsofwhichaccumulateduringthetimefromwhensomethinggoeswronginthesectionuntilemergencysystemsreact.C.EmergencySystemsTheSouthAfricanminingindustrybeganintroducingselfrescuersin19