Hydraulic drill jumbos an overview

HYDRAULIC DRILL HYDRAULIC DRILL JUMBOSJUMBOS

A COMPREHENSIVEA COMPREHENSIVE

PRESENTATIONPRESENTATION

Pinaki RoyPinaki RoyM. S. RaoM. S. Rao

BackgroundBackground

In order to create an opening in a In order to create an opening in a rock mass DRILLING is the basic rock mass DRILLING is the basic requirement.requirement.

Range & Selection of Drill Range & Selection of Drill JumbosJumbos

……………….for every Tunnel .for every Tunnel sectionsection

Single Boom JumbosSingle Boom Jumbos

Two Boom Jumbos (8 - 45 Two Boom Jumbos (8 - 45 sq.m.)sq.m.)

Two Boom with basket (8 - 90 Two Boom with basket (8 - 90 sq.m.)sq.m.)

Three Boom/Three Boom with Three Boom/Three Boom with Basket Boom Basket Boom

(upto 168 sq.m.)(upto 168 sq.m.)

Probing aheadProbing ahead

Drill Jumbo - Long HolesDrill Jumbo - Long Holes

Optional equipmentOptional equipment

Basic Basic requirement requirement

for rock drillingfor rock drilling

Rock Drilling - Rock Drilling - PrinciplePrinciple

Basic requirement :

Rock drill Rock drill mechanismmechanism

Impact Impact The piston transmits the The piston transmits the impact energy through the impact energy through the drill steel to the hole drill steel to the hole bottom. A valve directs the bottom. A valve directs the compressed air / hydraulic compressed air / hydraulic oil from one side to the oil from one side to the other of the piston so that other of the piston so that it moves up and down.it moves up and down.

Impact

RotationRotation The drill steel is turned lightly with The drill steel is turned lightly with

each blow. each blow. IN PNUEMATIC ROCK DRILLS :IN PNUEMATIC ROCK DRILLS :The rotation is normally anti-clock The rotation is normally anti-clock

wise and normally made on the wise and normally made on the return stroke of the piston. return stroke of the piston.

The theoretical angle of rotation per The theoretical angle of rotation per stroke is 36 degree. In practice it is stroke is 36 degree. In practice it is 30 degree. The difference is due to 30 degree. The difference is due to mating part.mating part.

IN HYDRAULIC ROCK DRILLS :IN HYDRAULIC ROCK DRILLS :Hydraulic motor is normally used for Hydraulic motor is normally used for

rotation. The rpm of the drill bit is rotation. The rpm of the drill bit is adjusted as per drill bit diameter. adjusted as per drill bit diameter.

Rock drill Rock drill mechanismmechanism

Rock drill mechanismRock drill mechanism

Feed forceFeed force

The feed force is created by hand The feed force is created by hand in case of hand held drills , in case of hand held drills , Pusher leg or hydraulic cylinder.Pusher leg or hydraulic cylinder.

Proper feed force will give the Proper feed force will give the best penetration rate.best penetration rate.

Improper feed force will cause:Improper feed force will cause: Loosening / damaging of Loosening / damaging of

thread.thread. Overheating / low life of drill Overheating / low life of drill

string.string. Diverted hole / poor pull in Diverted hole / poor pull in

blasting.blasting.

Rock drill Rock drill mechanismmechanism

FlushingFlushing

Flushing is done Flushing is done normally by air or normally by air or water on all the water on all the rock drills used in rock drills used in underground, underground, water is used as water is used as flushing media. flushing media. Optimum flushing Optimum flushing will provide better will provide better penetration rate.penetration rate.

Factors which influence drilling Factors which influence drilling raterate

Type of rockType of rock Air pressure/Hydraulic PressureAir pressure/Hydraulic Pressure Bit sizeBit size Bit conditionBit condition FlushingFlushing Feed forceFeed force Wear of front of rotation chuck Wear of front of rotation chuck

bushing bushing

Drifter - Heart of Drifter - Heart of Drilling JumboDrilling Jumbo

New Generation Rock Drill

Components of Hydraulic Components of Hydraulic DrifterDrifter

Shank AdapterShank Adapter Flushing HeadFlushing Head Damping PistonDamping Piston Stroke SelectorStroke Selector PistonPiston Rotation GearsRotation Gears CylinderCylinder AccumulatorsAccumulators Hyd. Rotation MotorHyd. Rotation Motor

DriverDriver

Transmit rotation from Hyd. Transmit rotation from Hyd. Motor to Shank AdapterMotor to Shank Adapter

Triangular in shapedTriangular in shaped Housed in rotation chuckHoused in rotation chuck Has internal splinesHas internal splines Made of bronze/SteelMade of bronze/Steel Splines wear limit is half it Splines wear limit is half it

original width.original width.

Stop RingStop Ring

Serves as retainer for Shank Serves as retainer for Shank AdapterAdapter

Stop Ring is extremely hard Stop Ring is extremely hard and wear resistantand wear resistant

It is subject to impact It is subject to impact energyenergy

Wear limit is 1 mm to the Wear limit is 1 mm to the front end of the splinesfront end of the splines

Damping PistonDamping Piston

Damping Piston protects the Damping Piston protects the Rock Drill from shock Rock Drill from shock waves (thru hydraulic waves (thru hydraulic pressure)pressure)

Subject to powerful axial Subject to powerful axial shock waves.shock waves.

It helps in absorbing reflex It helps in absorbing reflex shocks upto 20 tonnes. shocks upto 20 tonnes.

Since it is pressed against Since it is pressed against rot.chuck/shank adapter, it rot.chuck/shank adapter, it tends to partially rotate.tends to partially rotate.

Side BoltsSide Bolts

Two long side bolts hold Two long side bolts hold together the external parts together the external parts of the Rock Drill (front of the Rock Drill (front head, cover, gear housing, head, cover, gear housing, interm. part and cylinder interm. part and cylinder

Third long side bolts Third long side bolts connect all above parts connect all above parts except front head.except front head.

Two long side bolts have Two long side bolts have have integral eccentric have integral eccentric lugs(for tightening)lugs(for tightening)

Side BoltsSide Bolts

Tension of the side bolts Tension of the side bolts must be checked must be checked regularly.regularly.

Rear dome nuts are Rear dome nuts are tightened as per the tightened as per the recommended torquerecommended torque

Recommended to Recommended to change both the bolts change both the bolts together.together.

Piston GuidesPiston Guides

Front and Rear piston Front and Rear piston guides located on either end guides located on either end of the cylinder guides the of the cylinder guides the lateral movement of the lateral movement of the piston.piston.

It prevents the piston lands It prevents the piston lands from touching the cylinderfrom touching the cylinder

Its has wear resistant quality Its has wear resistant quality and also gives lowest and also gives lowest possible friction.possible friction.

Impact Piston Impact Piston

The piston strikes the shank The piston strikes the shank adapter between 3000 – adapter between 3000 – 3600 stokes per minute3600 stokes per minute

Piston is supported by Piston is supported by piston guides.piston guides.

Slim piston design transfer Slim piston design transfer optimum energy to the drill optimum energy to the drill stringstring

Slim piston design also has Slim piston design also has low stress on Rock Toolslow stress on Rock Tools

Rotation Chuck Sleeve Rotation Chuck Sleeve

Rotation Chuck sleeve Rotation Chuck sleeve is a press fitted into the is a press fitted into the rear of the Rotation rear of the Rotation ChuckChuck

It is made of high It is made of high quality bronze with high quality bronze with high resistance to wear and resistance to wear and frictionfriction

Rotation Chuck Bushing Rotation Chuck Bushing

The smaller front face of the The smaller front face of the Rotation Chuck bushing Rotation Chuck bushing acts on the shank adapter.acts on the shank adapter.

Larger rear face is subject to Larger rear face is subject to the thrust from the damping the thrust from the damping piston.piston.

Front face of the rotation Front face of the rotation chuck bushing is subject to chuck bushing is subject to steady wear.steady wear.

Max. permissible wear on Max. permissible wear on the front face of the rotation the front face of the rotation chuck bushing is 1 mm.chuck bushing is 1 mm.

Flushing Head Flushing Head

Rock Drill - ReflexRock Drill - Reflex

Hydraulic Rock Drills normally work at Hydraulic Rock Drills normally work at 200 Bar Impact Pressure200 Bar Impact Pressure

Every Impact of the Rock Drill Every Impact of the Rock Drill Generates 20 Ton Reaction / Reflex from Generates 20 Ton Reaction / Reflex from

RockRock

Reflex 20 Ton Drifter Impact

Drifter without Reflex Drifter without Reflex DampenerDampener

Reflex kills the Drifter & Reflex kills the Drifter & MountingMounting

Most effective Reflex Most effective Reflex DampenerDampener

CARE & MAINTENANCECARE & MAINTENANCE

ofof

HYDRAULIC DRIFTERSHYDRAULIC DRIFTERS

SAFETY REGULATIONSSAFETY REGULATIONS Special attention must be paid to safety information Special attention must be paid to safety information

and especially to the warning symbol (triangle).and especially to the warning symbol (triangle). Never attempt maintenance of Rock Drill when the Never attempt maintenance of Rock Drill when the

hydraulic system is pressurisedhydraulic system is pressurised Always use correct specification hoses, specially the Always use correct specification hoses, specially the

impact hose of rating SAE 100 R9R/4SH/4SP (4 layers, impact hose of rating SAE 100 R9R/4SH/4SP (4 layers, spirally wound steel wire braided).spirally wound steel wire braided).

Use protective plugs when dismantling the Rock DrillUse protective plugs when dismantling the Rock Drill Always overhaul a Rock Drill in a Container or a clean Always overhaul a Rock Drill in a Container or a clean

workshopworkshop

Start UpStart Up

Before starting up a new or a newly overhauled Rock Before starting up a new or a newly overhauled Rock Drill:Drill: Connect up all hydraulic hosesConnect up all hydraulic hoses Charge the Accumulators with Nitrogen gas to the Charge the Accumulators with Nitrogen gas to the

correct pressurecorrect pressure Fill correct hydraulic and lubricating oilFill correct hydraulic and lubricating oil Adjust correct lubricating systemAdjust correct lubricating system

Tighten all threaded joints after first shift of operationTighten all threaded joints after first shift of operation

Every ShiftEvery Shift

CheckCheck that Air & Lubricating oil come out that Air & Lubricating oil come out between the shank adapter and front guidebetween the shank adapter and front guide

Check S/Adapter threads are not damagedCheck S/Adapter threads are not damaged Keep an eye on the hydraulic hose vibration. Keep an eye on the hydraulic hose vibration.

If they vibrate too much check the If they vibrate too much check the Accumulators.Accumulators.

Check there is no leakage from the Rock Check there is no leakage from the Rock Drill. If flushing water leaks from the hole Drill. If flushing water leaks from the hole in the front head, change the seals.in the front head, change the seals.

Every 40 Percussion HourEvery 40 Percussion Hour

Grease the Gear HousingGrease the Gear Housing Tighten all threaded joints as per Tighten all threaded joints as per

specified torque.specified torque. Check for external leakage on the Rock Check for external leakage on the Rock

Drill. Replace the seals if leakingDrill. Replace the seals if leaking Check condition of hydraulic hoses, Check condition of hydraulic hoses,

replace damaged/defective hoses.replace damaged/defective hoses.

Every 400 Percussion HourEvery 400 Percussion Hour

Recommended for complete Recommended for complete overhaul.overhaul.

Overhauling to be done in a clean Overhauling to be done in a clean and suitable workshop. Always use and suitable workshop. Always use Hydraulic Drifter Repair Tools.Hydraulic Drifter Repair Tools.

AccumulatorsAccumulators

Accumulators are fitted with Accumulators are fitted with safety labelssafety labels

They should be charged with They should be charged with Nitrogen gas only (other gas can Nitrogen gas only (other gas can cause explosion)cause explosion)

All new accumulators are not All new accumulators are not chargedcharged

Charging the AccumulatorsCharging the Accumulators

Remove the protective plugsRemove the protective plugs Open the valve nut and connect the charging hoseOpen the valve nut and connect the charging hose Open the gas valve on the cylinderOpen the gas valve on the cylinder Charge the Accumulator to the collaring pressure Charge the Accumulator to the collaring pressure

minus 30 bar. However the maximum pressure minus 30 bar. However the maximum pressure should not exceed 110 barshould not exceed 110 bar

Tighten the valve nut and also close the cylinder Tighten the valve nut and also close the cylinder valve.valve.

Remove the charging hose and fit back the Remove the charging hose and fit back the protective cap on the accumulator valveprotective cap on the accumulator valve

AccumulatorsAccumulatorsIntake :

30 bar belowcollaring pressure

Max - 110 bar

Damping : 20-25 bar

Return : Not to be charged

MAIN COMPONENTS OF DRILL JUMBOS

• CARRIER

• BOOM

• FEED

• ROCK DRILL

• POWER PACK

Carrier

Power train

Carrier SystemCARE & MAINTENANCE

Engine – Air Filter

1.Clean every week2.Change interval

normally depends on environment

Engine – Oil & Filter

Change interval depends on different factors:

a. Quality of oilb. Working tempc. Environment

Engine – Fuel Filter

Change interval normally depends on quality of fuel

Carrier GreasingGrease every week.Check once in every month whether grease is passing through every point

Drive line : greasing

Grease every point once in a week.

Only two stroke of grease is sufficient.

Use good quality grease.

Check bolt torque weekly

Coolant Level

Check Coolant

level daily

Transmission Oil & Filter

Change interval depends on different factors:

a. Quality of oilb. Working tempc. Environment

Transmission oil change

A - FillingB - Drain C - Filter

Drain the oil when it is hot through drain plug “B”. Fill the oil through port “A” up to “LOW” mark on dipstick. Change the filter.Run the engine at low idle to fill up the

converter and fill oil up to low mark.Run the engine to heat up the oil at 80 deg. C

fill up to high level.

Differential

Check level every week

Change every 500

hours

Planetary hub

Check level every week

Change every 500

hours

Release Park brake

Loosen lock nut “A”Screw in stud “B” to the bottom.

To reset the park brake screw out the stud “B” to 47 mm.Tighten the lock nut.

Service brake adjustmentPlace the rig on jacks. Open the lock nut “A” & lock plate “B”.Unscrew the adjusting screw “C” anticlockwise to take up any play. Continue to turn until a torque of 40 Nm is attained.

Now screw the adjusting screw “C” clockwise 3 turns.Refit lock plate “B” & lock nut “A”.

Hydraulic Booms

A

B

C

Cross cut drilling

Hydraulic Booms

Rotation unit

Boom Hydrauli

cSystem

Cylinder movement - Vertical

Cylinder movement - Horizontal

Maintenanc

e

Adjustment - Feed cradle

Cradle clearance adjustment

Replacement of guide rail

In Conclusion….

Drilling is the backbone of all mining & tunneling applications & thus the role of Electro Hydraulic Drill Jumbos assumes critical proportions.While these equipment are quite simple to operate with built in ling term reliability, optimization of drilling functions and high levels of availability is only possible if correct maintenance and operational directions are followed.

The presenters of this paper thankfully acknowledge the assistance from M/s Atlas Copco & M/s Sandvik for their inputs during preparation.