Rotary blast hole drillinggood practice guide
2 • GOOD PRACTICE GUIDE
GOOD PRACTICE GUIDE • 3
Rotary blast hole drillinggood practice guide
4 • GOOD PRACTICE GUIDE
GOOD PRACTICE GUIDE • 5
INTRODUCTION ........................................................................................................................................................... 6
THE DRILLER .................................................................................................................................................................. 6
PRE-DRILL SETUP AND INSPECTION ............................................................................................................... 7
Bit pre-start inspection .................................................................................................................................. 7
Bench preparation ............................................................................................................................................. 7
Tramming ................................................................................................................................................................. 7
Proper drill rig set-up and operation guidelines ........................................................................... 8
Raising the drill rig ................................................................................................................................................ 8
Lowering the drill rig ............................................................................................................................................. 8
Raising and lowering the mast ........................................................................................................................... 8
Correctly drill out a pattern ................................................................................................................................ 8
DRILLING PROCEDURES .......................................................................................................................................... 9
Running-in new bits .......................................................................................................................................... 9
How a roller cone bit drills rock .............................................................................................................. 9
Penetration rate ...................................................................................................................................................... 9
Abrasion phase ....................................................................................................................................................... 9
Fatigue phase .......................................................................................................................................................... 9
Spalling phase.......................................................................................................................................................10
Rock failure/Spalling phase ...............................................................................................................................10
Excess weight ........................................................................................................................................................10
Pulldown ................................................................................................................................................................11
Precautions ............................................................................................................................................................11
Rotation .................................................................................................................................................................11
Excessive RPM ......................................................................................................................................................11
Collaring .................................................................................................................................................................11
Guidelines for WOB and RPM ..........................................................................................................................11
Bailing air pressure, air volume and nozzles ................................................................................12
Nozzle size ............................................................................................................................................................12
Bailing velocity ......................................................................................................................................................12
Drilling with water .........................................................................................................................................12
Drill string ............................................................................................................................................................13
Refueling and servicing ...............................................................................................................................13
BIT SELECTION ...........................................................................................................................................................14
Hard formation bits ............................................................................................................................................14
Soft formation bits ...............................................................................................................................................14
BIT MAINTENANCE ..................................................................................................................................................15
Cleaning procedures ......................................................................................................................................15
Storage ....................................................................................................................................................................15
Air bearing bits .....................................................................................................................................................15
Sealed bearing bits ..............................................................................................................................................15
Bit subs and tools ................................................................................................................................................15
TROUBLESHOOTING ...............................................................................................................................................16
GLOSSARY ......................................................................................................................................................................18
Table of Contents
6 • GOOD PRACTICE GUIDE
INTRODUCTION
Rotary drilling with roller cone drill bits and
their application in blast hole drilling over the
past few years has changed in two main areas:
• Theamountofpulldownorweightonbit(WOB)used.
• Theamountofrotationspeed(RPM)used.
Withrotarybitscontinuallyimproving,we
mustkeepupwiththeseimprovementsto
optimize performance of the drill rig and drill
string.
Ofcourse,thereareothercriticalfactorsthat
contributetothemaximumperformanceofthe
drillingoperation,someoftheseinclude:
• Thedriller’sknowledgeandskill
• Benchpreparation
• Drillrigsetup
• Efficientrigsetupoverthedrillpoint
• Correctbitbreak-inandmaintenance
• Efficientpatterndrillout
• Drillstring
• Refuelingandservicing
• Bailingairpressureandvolume
• Correctbitselection
• Housekeepingandmaintenance
Thesefactorsareconsideredindividuallyand
togetherinatroubleshootingsectionattheend
ofthisguide.
NOTE:Site-specificprocedurestakepriority
over the generic rotary drilling good practice
techniquesprovidedinthisguide.
THE DRILLER
Thedrilleristhemostcriticalfactorin
optimizingdrillperformance.Thedriller’sskill
andknowledgeiscriticaltoachievingthefull
potentialofthedrillanddrillstring(including
thebit).
Blastholedrilling,inmostcases,isnotaset
andforgetoperation.Asthegroundconditions
change,thedrillertoomustadapttothe
changingconditionsanddrillaccordingly.Some
guidelinesinclude:
• Ensuresafetyisalwaysthehighestpriority.
• Beattentiveatalltimes.
• Don’tbecomeasetandforgetdriller.
• Keepthedrillclean.
• Keepcomponentsandtoolscleanandproperlystored.
• Maintainharmonyinyourdrillrig/string.
–Avoidexcessivevibrations.
–Avoidoverloadingoftheequipment.
• Don’tleavecontrolsunattendedwhendrillingaholeortrammingthedrill.
• Reportallmechanicaldefectsdaily.
• Inspecttherigdaily.
• Ensureagoodchangeoverwiththeothercrew.
• Ensurepre-startinspectionsaredonecorrectly.
• Ifshocksubsrequiregreasing,greasethemattheproperinterval(shift,daily,weekly,etc.).
Rotary blast hole drilling good practice guide
GOOD PRACTICE GUIDE • 7
PRE-DRILL SETUP AND INSPECTION
Bit Pre-Start Inspection
Note:Tobedoneatthestartofeachshift.
Inspectthebitpriortobeginningtodrillateachshift.
• Ensureallconesturn.
– Sealedbearingbitswillbehardertoturnbyhand.
– Neverhitabitwithasteelobjectoruseasteelobjecttoturnthecones.
• Checkforbrokenormissingcarbideinsertsandnoteonpre-startreport.
Checkforclearairpassagesbyflushingwithairandwater.
Airandwatershouldexitfromthebottomofeachshirtail
(onairbearingbitsonly)andfromeachnozzle.(Photo1)
Unlockbogged(plugged)bitsbyflushingwithairandwater.
• Useverylowrotationspeedandminimalbitweightandrunthebitontheground.Thisshouldfreeupthebearingstogivefurtherbitlife.(Photo2)
• Ifthisdoesnotwork,removethebitfromservice.Removetheairscreeningtubesfromwithinthebitandcleantheairpassagewithahighpressurecleaner.Onceclear,replacethecleanscreeningtubesandputthebitbackintoservice.
Bench preparation
Benchesshouldbesmoothandlevelpriortodrilling.
(Photo3)
• Ifyoucan’tjackthemachinelevel,donottakethemachinethere.
• Ifyoucan’tlevelthedeck,don’toperatethemachine.
• Whiplashingofthemastonunevengroundunnecessarilywearsoutcomponentsandstressesweldsinthemast.
Tramming
• Turnofftheflushingairwhentramming.
• Putdownthemastwhentrammingoveranydistanceorroughground.
• Useappropriatespeedwhenencounteringunevenground.
• Avoidtrammingoveroldtramtracks,obstaclesorpreviousturns.
• Oververylongdistances,tramfor20minutes,thenrestfor20minutestocooltheexcavatorbasedundercarriage.
Photo 1Checking air passages
Photo 2Bogged bits
Photo 3Drill on correctly prepared bench
8 • GOOD PRACTICE GUIDE
Proper drill rig set-up and operation guidelines
NOTE:Followyourdrillrigorsite-specificprocedures.
Raising the drill rig
• Followcorrectrigraisingprocedure-rearfirst,thenthefront.
• Avoidtwistingthemachinechassiswhileraisingtherig.
• Whenlevelingthedrill,donotviolatethemanufacturer’srecommendationforextendingandretractingthejacks. Improperlevelingcouldresultinashiftinthecenterofgravity,causingadrilltorollover.
• Onlyraisetherigashighasisneededtogetitlevel. (Photo4).
Lowering the drill rig
• Lowerthedrillinreverseorder:frontfirst,thenrear.
• Ensuredrillstringisfullyretractedbeforeloweringthe drillrig.
Raising and lowering the mast
• Onlyraiseorlowerthemastwhentherigisleveledonitsjacks.
• Priortoraisingorloweringthemast,retractthedrillstringasperOEMspecifications.
• Ensurenolooseobjectsareinthemastbeforeraisingit.
• Beawareofoverheadobstructions,especiallypowerlines.
• Operatethehydraulicsinasmoothmanner;avoidrockingthemast.
• Besurethemastsidecabdoorisclosed!
• Ifthemastisdifficulttomove,ensuretherigisleveledcorrectlyandthelockingpinisfullyretracted.
Correctly drill out a pattern
• Inspectandwalkthepatternpriortobeginningtodrill.
• Makeaplanandadheretoit.Communicatemovementplanswithotheroperatorsandsupervisors.
• Whentramminganelectricdrill,protectthepowercablefromdamagefromtrammingoverit.Alwayspre-inspecttheareatomakesurethepowercableispulledofftothesideofthepathwherethedrillwillmove.Checkthecablelocationperiodicallyinrelationtothetrammingpath.
• Keepdrillrigsasafedistanceapartduringoperation,over46feet(14meters)orassiterulesdesignate.(Photo5)
• Leaveanaccesspathforservicecartsandvehicles.
• Notedangerareasandpassthemontothecrossshiftsupervisor.
• Drillallholesinthecorrectspot,atthecorrectangleandtothecorrectdepth.(Photo6)
• Drilloutthehardesttoreachholesfirst.
• Avoidscrewingthedrillaroundonthepattern,ifpossible.
• Dipyourholestoavoidre-drilling.
–Asarule-of-thumb,re-drillscost3 times the cost of a normalhole.
Photo 4Properly leveled rig
Photo 5Drill rigs too close
Photo 6Properly spaced holes
GOOD PRACTICE GUIDE • 9
DRILLING PROCEDURES
Running-in new bits
Allnewdrillbitsshouldbebroken-inatreducedweightand
rotationspeedstoensurethatallworkingsurfacesarerun-in
andslightlyworkhardenedpriortoapplyingfulloperating
load.Ingeneral,followingtheserecommendedguidelines
shouldmaximizebitlife(Figure1):
1.Drillat50%ofnormalweightandrotationforthe
first10minutes(orforthefirstrodinamulti-pass
operation).
2.Drillat75%ofnormalweightandrotationforthenext
10minutes(orsecondrod).
3.Drillasnormal(100%).
How a roller cone bit drills rock
Penetration rate
Figure2illustratestheeffectWOB(weightonbit)hason
ROP(rateofpenetration)whiletheRPMarefixed.Afterthe
rockhasbeenspalled(PointA),additionalweightwillonly
reducethedrillingrate.
Abrasion phase
Figure3illustratesthefirstphaseofrockfailure.
BecausetheWOBisnot
sufficienttoovercomethe
surfacestrengthofthe
rock,theinsertswearthe
rockratherthandrillit.
Thecuttingactionis
similar to sharpening a
knifebladeonagrinding
stone.Thedrillercan
easily identify this phase
becausethecuttingreturns
comingoutoftheholeare
averyfinepowder.
Fatigue phase
InFigure4,theWOB
has been increased while
maintainingthesameRPMasinthepreviousexample.By
addingWOB,theinsertsarenowpenetratingslightlyintothe
rock.Eventhoughtheinsertsarebeingforcedintotherock,
rockfailurehasoccurred.Thisphaseiscalledthefatigue
phaseofrockfailure.
Figure 1Drill Bit Run-In
Figure 2 Penetration rate
Figure 4Fatigue phase
Figure 3Abrasion phase
10 • GOOD PRACTICE GUIDE
Thedrillerwillrecognizethisphasebecausethecutting
returnswillcontainsomesmallchipsalongwiththefinedust.
Bysubjectingtherocktomanycycles,rockfailurecanoccur
inthisphase.Eventhoughtherockfailurecanoccur,ROP
willbeveryslowandbitwearwillbeincreased.
Spalling phase
Inthespallingphaseofrockfailure,whiletheRPMremain
constant,enoughWOBhasbeenappliedtoovercomethe
surfacestrengthoftherock.Figure5indicatesthecone
matrixisnotimpingingontherock.
Rock failure/Spalling phase
Figure6indicatesthatproperWOBgeneratesaspalling
orchippingaction.Thechipsarecirculatedupandoutof
theholebythebailingair,allowingthecuttingstructureto
advanceonacleanholebottom.
Whenthedrillingparameterscauseadrillbittooperatein
this“zone”,thebitisdrillingatmaximumefficiency.
Thedrillerwillknowthespallingphasehasbeenachieved
becausethecuttingreturnswillbepredominatelychipswith
verylittledust.
Whendrillinginthespallingphase,higherratesof
penetration(drillingefficiency)canbeachievedbyincreasing
theRPMwhiletheWOBremainsconstant.Theactual
increaseinefficiencydependsontherockcharacteristics,and
thedrillanddriller’scapabilities.
NOTE:Theprecedingdiscussionistrueforbrittlerock.The
mechanicalcharacteristicsofhighlyelasticrockmightbehave
moreliketheillustrationonthefatiguephase(Figure4)
insteadofthespallingphase(Figure5).
Excess weight
Addingmoreweightonthedrillbitafterachievingthe
spallingphaseisharmfultodrillingefficiencyandthedrillbit
life.Figure7illustrateshowtheconematrixisimpingingon
therockformation,trappingthespalledchipsbetweenthebit
andtheholebottom.Theresultisreducedbitproductivity
andincreasedwearandtearonthedrillbit.
Figure 5Spalling phase
Figure 6Rock failure/Spalling phase
Figure 7Excess weight
GOOD PRACTICE GUIDE • 11
Pulldown
Theamountofpulldownforce(WOB)requireddepends
mainlyonthetypeofgroundthatisbeingdrilled.Thereisno
pointinexceedingoptimalpulldownforthepenetrationrate
forthegroundconditions.
• UsetheROPgaugetoachieveastableandsmoothpenetrationrate.
• Therotationtorqueshouldbesmooth.Spikingtorquecanindicateexcessiveweightonbit.
ConditionswithcorrectWOB:
• Cabisstable,levelandsmooth.
• ThedrillerfeelslimitedvibrationforsufficientROP.
ConditionswithinsufficientWOB:
• Cabbouncesexcessively.
• LowROP.
Precautions
Overdrillingofarollerconebitreducesbitlife.
• Acceleratesconesteelandshirttailwear.
• Promotesinsertlossandbearingexposure.
• Overloadsthebearings.
• Canpotentiallyplugairpassagesandoverheatbearingelements.(Pluggingmaybeindicatedbyanincreaseincabairpressuregauge.)
Rotation
Usingthecorrectrotationspeed(RPM)foranapplication
iscriticalforeffectiveandefficientdrilling.Followthese
guidelines.
• Alwaysuserotationandairwhenenteringorexitingahole.
• DecreaseRPMinbrokenoruncertainground.
• Rotationtorqueshouldbestableundernormaldrillingconditions.
• WhendecreasingtheRPM,increasetheWOB(andviceversa).
• Insoftformations,usehigherRPMandlowerWOB.
• Inharderformations,uselowerRPMandhigherWOB.
Excessive RPM
• Causesearlywearorfracturetocarbideinserts.
• Causesinsertstoskiponsurfaceratherthanpenetratingtherock.Thisismostsignificantinharderformationsbutrelevanttoallformations.
• Reducesbearinglife.
Photo 7Showing good drill collar
Collaring
• CollarallholesatreducedRPMandWOB.Thishelpsavoidholedeviation.(Photo7)
• Incoarsesub-drillorhardrockapplications,useminimalWOBandRPMtoavoiddrillbitdamage.
• Oncecompetentrockisreached,increaseWOBandRPMtonormallevels.
Guidelines for WOB and RPM
Recommendedmaximumpulldownvaries
considerablyonthespecificapplications.
Refertothemanufacturer’sguidelinesforthe
appropriatebitsize.
12 • GOOD PRACTICE GUIDE
Bailing air pressure, air volume and nozzles
Bailingairpressureandairvolumeplayanintegralpart
inachievingoptimalbitlifeandpenetrationrates.There
mustbesufficientairpressuretocoolandlubricatetheair
bearingswithintherollerconebit.Sufficientairvolumeis
alsorequiredtoefficientlyremovethedrillcuttingsfromthe
bottomoftheholeasrapidlyaspossible.
Nozzle size
Theamountofinternalairpressureisregulatedby
nozzlesize.
• Increasethenozzlesizetoreducepressureinsidethebit.
• Decreasethenozzlesizetoincreasepressure.
• Nozzlessizesaredeterminedperrig.
–ConsultwithyourSandvikrepresentativeorbitmanufacturerpriortochangingnozzlesizes.Sandvikwillorganizeanairtesttoconfirmthecorrectnozzlesizeforyourspecificapplication.
Nozzlethebittoachievepressuresofapproximately
35-40psi(2.4-2.8bar)inthedrillbit.
• Notethatcabpressuregaugescanreadsignificantlyhigherthanthisvalue.Asarule-of-thumb:thedifferencebetweencabandatthebitis8-10psi (0.5-0.7bar).
• Reportsignificantchangestocabgaugepressureovertheshift.
Remembertokeepthebailingairturnedonuponexitingand
enteringahole.
• Turnontheairbeforetouchinggroundtostartanewhole.Thiscoolsandflushesthebearingsandensuresairpassagesareclearpriortostartingthehole.
Bailing velocity
Airvolumetocleantheholeisreferredtoasbailingvelocity
(BV).Generallyspeaking,thehigherthebailingvelocity,the
better the hole is cleaned and the higher the penetration rates
andbitlife.
• Anup-holebailingvelocityof6000-7000feetperminute(fpm)(30-36m/s)issufficientinlighttomediummaterials(typicallycoaloverburdens).
• Inmoredensematerials(hardrockmines,ironore,etc.)orwhenencounteringgroundwater,maintainanup-holebailingvelocityof7000-10000fpm(36-50m/s).
Drilling with water
Waterisoftenrequiredduringdrillingfordustsuppression
andtoensureholequality;however,theuseofwatercan
severelyshortenbitlife.
• Donotusemorewaterthanisnecessarytooperateefficientlytosuppressdustandprotectyourhealth.
• Holeslefttostandopenforextendedperiodswillrequireincreasedwatertopreventcollarcollapseorfallback.
• Donotwaituntilthewatertankisemptytorefillit;thisgeneratesunnecessarydowntime.
GOOD PRACTICE GUIDE • 13
Drill string
• DetermineOEMlimitsforrefurbishment/discard.Checkpipesizefrequently.Reportundersizeequipmentimmediately.
• Avoidexcessiverodrattleorbounceasthisreducescomponentlifeandpenetrationrates.
• Monitordeckbushingsandbitbasketsforexcessivewearandreplacewhennecessary.(Photo8)
Refueling and servicing
• Followanysitespecificrulesregardingservicingofthedrillrig.
• Leaveapathwithinthepatternforservicetrucksand watercart.
• Stopdrillingasvehiclesapproach.
• Usedustsuppressiontoavoiddustingpeopleontheground,assiterulesdesignate.
Photo 8RP434 rotary deck bushing
14 • GOOD PRACTICE GUIDE
10 5/8" (270 mm) 60QX2Hard formation
BIT SELECTION
Bit selection can be a critical factor in the performance of a drilling
operation.
• Correctbitselectionisessentialforoptimalbitperformance.
• Thecorrectbitforaformationwillhaveoptimalpenetrationratesandgoodbitlifegivingthelowestcostperdrilledmeter.
ConsulttheSandvikorothermanufacturers’productselectionchartsto
evaluatethecorrectbittypefordrillingconditions.Thesechartsarealso
availableintheproductcataloguesandcoverbothourUltraPremium
SealedBearing(RR440,Charger)andPremiumAirBearing(RR320)
productlines.
Ifthereisanydoubtthatthecorrectdrillbitisusedatyoursite,contact
yournearestSandvikarearepresentative.
Hard formation bits
• Whenusedinsoftformationareas,thesebitswillhavelowpenetrationratesandreducedbitlife.
Soft formation bits
• Ifusedinhardformationareas,thesebitswillsufferearlycarbidewearandfailure.
Anexampleofthecuttingstructurevisualdifferencesisshowninthe
imagesbelow.(Photo9)
Photo 9
10 5/8" (270 mm) 17QX2Soft formation
10 5/8" (270 mm) 30QX2Medium formation
GOOD PRACTICE GUIDE • 15
BIT MAINTENANCE
Cleaning procedures
Cleanalldrillbitsattheendoftheshift.
• Flushbitswithairandwatertoremovedebrisandmud. (Photo10)
• Stopwaterwhenit’scleanandcontinuetoflushwithairfor1minuteoruntilbitisdry.
• Whenbitiscleananddry,applyaspraylubricanttothebearingsifavailable.
(Note:Lubricantshouldbeusedonairbearingbitsonly.)
Storage
• Storeusedandnewbitsinacleandryarea.(Photo11)
• UsetheoriginalSandvikbox,ifpossible.
• Coverthreadstopreventdustbuildup.
Air bearing bits
Forextendedstorage,storeairbearingbitsinasealed
containerwithenoughdieseltocoverthebearings.Thisis
usefulduringholesizechangesorextendeddrillservicing.
Sealed bearing bits
Cleananddrybitswithair,thenstoreinasealedboxor
container.
IMPORTANT:ChargersealedbearingbitsshouldNOTbe
soakedindieselorotherfluidsorgreases.
Bit subs and tools
Storebitsubsandotherdrilltoolsinasafeandsecure
manneronthedrilldeck.Thedrilldeckshouldbeclean,
organized,andfreeofdebrisandrubbish.(Photo12)
Photo 10Flush bit with air and water
Photo 11Proper storage
Photo 12Deck storage for subs and other tools
16 • GOOD PRACTICE GUIDE
TROUBLESHOOTING
Dull bit evaluation
Foranevaluationofdullbitconditionandpossiblecauses,pleaseconsult
the Sandvik User's Handbook: A Guide to Using Roller Cone Rock Bits in
Mining.
Application failures
Basedonthetopicscoveredinthisguide,Tables1and2showpractical
examplesofcommonobservationsandfailuresnotedinminingoperations.
Thesearegeneralizedandmeantasanapproximateguideonly.Please
consultwithyourlocalSandvikarearepresentativeonanyspecificfailures.
TABLE 1
Typical Drill Cuttings Typical Dull Bit ConditionPhase / Observations
Abrasion Phase Insufficient weight
Observations Excessive insert wearFine dust-like cuttings
Spalling Phase Correct weight
Observations Even wear to cutting structureGood chip formation in cuttings
Excess Weight Overdrilling
Observations Excessive cone erosion, insert loss, premature cutting structure failureLarge variation in chip formationdue to regrind
Correct Weight on Bit Evaluation
GOOD PRACTICE GUIDE • 17
TABLE 2
Typical Drill String Condition Typical Dull Bit ConditionPhase / Observations
Low Bailing Velocity Thinning of sub above tool joint
Observations Excessive shirttail wear, early exposure of bearing elements
High Bailing Velocity
Observations Sandblasting of bit sub resulting in severe thinningLoss of cone steel and inner row inserts
Correct Bailing Velocity
Observations Even wear to bit subEven wear to cones and shirttails
Correct Bailing Air Evaluation
18 • GOOD PRACTICE GUIDE
Annulus
Theclearanceinthedrillholebetween
thedrillpipeandthewallsofthehole.
API
AmericanPetroleumInstitute.
Bailing Air
Compressedairthathaspasseddown
insidethedrillstringtoliftdrillcuttings
tothesurface.
Bench Drilling
Thedrillingofblastholesforbench
blasting,whichisthesimplestform
ofblasting.Abenchhasafreesurface
atthefronttowardswhichtherockis
blasted.Benchdrillingcanbecarried
outbothoverandundergroundand
drillingcanbedirectedupwards,
downwardsorhorizontally.
Bit
Thetoolusedinthedrillingoperation
whichcutstherockorsoil.
•Carbide
Abithavinginsertsoftungstencarbide.
•Roller
Adrillbitconsistingofapinshank,pin
shoulder,bitlegincludingshirttail,three
separateconeswithcutterteeth,nozzles,
andastampeddescription.Thethree
coneswithrotatingcuttersrollasthe
bitisrotated.
Blast Hole
Averticaldrillhole4inches(102mm)
ormoreindiameterusedforachargeof
explosives.
Box
Thefemaleendofadrillpipe.
Box Thread
ThefemalesideofAPI,IF,BECOorRH
thread.
Carousel
Therotatingcomponentsofthepipe
storageandloader.
Centralizer
Adevicetoassistinalignmentofdrill
steelinthemast.Primarilyusedfor
angle drilling applications or single pass
machines.
Collaring
Startingadrillhole.Whenthehole
isdeepandsolidenoughtoholdthe
bitfrommovingabout,itissaidtobe
collared.
Deck Bushing
Areplaceablebushinglocatedinthe
masttable.Thisbushingcentralizesthe
drillpipesastheypassthroughit.
Drill
•BlastHole
Amachinecapableofdrillingholes
4inches(102mm)ormoreindiameter
toadepthof100feet(30m)ormore.
•Percussion
Apneumaticorhydraulicpowered
deviceusedtobreakrock.
Drill Bit
Oneofanumberofdifferenttypesof
detachablecuttingtoolsusedtocuta
circularholeinrock,wood,metal,etc.
Drill Pipe
Thesectionsofarotarydrillingstring
usedtoadvancethedrillbitorDTH
intotheground.
Drill String
Allrotatingcomponentsconnected
together between the rotary head and
drillbit.
Down-The-Hole-Hammer (DTH)
Apneumaticpoweredrockdrill.A
chuckdriver,drillbit,retainingrings
andafootvalveforthistypeofrock
toolmakeaveryefficientdrilling
method.
Feed Cylinders
Hydrauliccylinder(s)usedtofeedand
retract the drill string by means of a
chainandsprocketorcableandsheave
arrangement.
Flushing Medium
Water,mud,airorfoamusedtoflush
drilled-outmaterialoutofthehole.
Holding Wrench
Awrenchtoolfixedtothedrillplatform
andusedtoholddrillpipeandsubs
topreventthemfromturningwhen
makingandbreakingjoints.
Jacks
Athree-pieceassemblyusedtosupport
ablastholedrill.Atypicalblasthole
machinehasthreeorfourlevelingjacks.
Fourlevelingjacksarestandardon
largermachines.
Lifting Plug/Bail
Liftingplugs/bailsareusedtohandle
heavyequipmentsuchasDTH
hammers,stabilizers,andsubs.
Loader
Arotatingrackdesignedtoholddrill
pipes,positionedinsideoroutsidethe
mast.
GLOSSARY
GOOD PRACTICE GUIDE • 19
Multi-Pass Drilling
Drillingtosuchdepthasrequiresthe
useofmorethanonedrillpipe.
Pattern
Blastpatternthatshowsholeplacement,
depthincludingsubgradedepth,burden
andspacing.
Pin
Themaleendofadrillpipe.
Pin Thread
ThemalesideofAPI,IF,BECOandRH
taperedthread.
Pipe Support
Mechanismstosupportdrillpipeinthe
mastduringpipechangingoperations
whenangledrilling.
Power Tong
Thehydraulictoolfixedatthebottom
ofadrillmast,usedtoclampandturn
tightdrillstringcomponents.
Propelling (Tramming)
Theactofdrivingacrawlermounted
drillineitherdirection.Alsomaybe
referredtoastramming.
Pulldown
Theforceusedtopressthedrillstring
and bit against the bottom of the
hole.Itiscontrolledbythehydraulic
pressureinthefeedcylinders(uptothe
reliefvalvesetting),andisrelatedto
theoverallweightofthedrillrig.The
pressureatthebitwillbethesumofthe
pulldownforceplustheforceexertedby
theweightofthedrillstring.Thetermis
alsousedtospecifythepulldownforce,
whichisavailablefromaparticular
drill.
Receiver
Theairtankorreservoirina
compressorsystem.
Rotary Head
Thehydraulicallydrivengearboxthat
turnsthedrillstring.
RPM
RevolutionsperMinute.
ROP
RateofPenetration.
Single Pass Drilling
Drillingwhichiscompletedinonlyone
pass.
Spacing Stabilizers
Adevicetoassistcenteringthebitin
thehole,preventingholedeviationand
providingequalweightdistributionto
eachrotarycone.Itisnormallyplaced
immediatelybehindthebit.
Sub
•BitSubs
Usedtoconnectbits,whichhaveanAPI
thread,tothedrillpipes,whichmay
haveAPI,IF,RH,BECOthreads.
•WaterSeparatingSub
Avariationofabitsubwhichremoves
water from the bailing air and ejects it
priortoitenteringthedrillbit.Thisis
designedtoextendbitlife.
•SaverSubs
Connectorsbetweendrillpipes,drillbits
and the rotary head that save the thread
of these components from the effects of
constantuse.
•ShockSubs
Toolsthatabsorbshockandvibration
witharesilientrubberelement,
preventing metal to metal contact in the
drillstring.
•TopSub
Asaversubusedontherotaryhead.
Thread Protectors
Coverswhichpreventdamageand
contamination of the threads on drill
stringcomponents.
Tooling
Toolsusedtomakeandbreakdrill
stringjoints,e.g.autotong,holding
wrench.
Torque
Therotationalpressurecreatedbya
hydraulicmotorandtheplanetary
reductiongearsmountedonarotary
head.
Up-Hole Velocity/Bailing Velocity
Theupwardspeedofthebailingairin
theannulusofthedrillhole.
Water Injection
Additionofasmallquantityofwaterto
thebailingairinordertosuppressdust.
WOB
WeightonBit.
Work Deck
Thedeckatthebaseofthemastwhich
gives access to components in the
drillingarea.
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Sandvik is a high-technology engineering group with world-leading positions in selected areas – tools for metal working, advanced materials technology, and mining and construction. We are represented in 130 countries.
Sandvik Mining and Construction represents one third of the overall Sandvik Group and serves a broad range of customers in construction, mineral exploration, mining and bulk materials handling. Our construction expertise covers quarrying, tunneling, demolition and recycling, and other civil engineering applications. Our mining products and services support customers on the surface and under ground, in all mineral, coal and metal mining applications from exploration to ore transportation.
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