TUBEX XL DTH DRILLING TOOLSdrilling. It enables holes to be drilled successfully through all kinds of overburden, even that in which boulders of varying sizes are suspended. With the

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USER´S HANDBOOK

Mission overburden rock drilling tools

TUBEX XL

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TUBEX XL User’s handbook

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Contents Page

Description of the TUBEX XL method ....................................... 2

Equipment and function............................................................... 6

Tophammer equipment ................................................................ 8

Down-the-hole equipment ............................................................. 9

Casing tubes ................................................................................. 11

Bevelling/chamfering .................................................................. 12

Cutting ......................................................................................... 13

Joining ......................................................................................... 13

General comments on welding .................................................... 13

Welding casing shoe and bit tube ................................................ 15

Drilling method and procedure .................................................... 15

Down-the-hole drilling ................................................................ 16

Preparations for drilling ............................................................... 18

Tube handling .............................................................................. 18

Setting up the drill rig .................................................................. 20

Drilling ........................................................................................ 20

Telescopic drilling ....................................................................... 21

Drilling data - recommendations ................................................. 22

Pulling up the drill string ............................................................. 25

Termination of TUBEX XL drilling ............................................ 25

Breaking of joints ........................................................................ 26

Continued drilling with TUBEX XL ........................................... 28

Continued drilling with regular DTH .......................................... 28

Drilling with foam ....................................................................... 29

Equipment lost down the hole ..................................................... 30

Tophammer drilling ..................................................................... 30

Wear and service life ................................................................... 30

Build-up welding (hardfacing) .................................................... 31

Product range ............................................................................... 32

Important points ........................................................................... 34

Areas of application ..................................................................... 34

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DESCRIPTION OF THETUBEX XL METHOD

Approximately 90 percent of theearth’s surface is covered withlayers of soil, clay, gravel, sandor moraine. This covering isknown as overburden. Thethickness of the overburden, i.e.the distance from the surface tothe bedrock, varies considerably.It can be any-where between afew centimetres and severalhundred metres.

It is impossible to drill throughloose overburden using conven-tional drilling methods. This isbecause the hole walls collapsecontinuously, which renders thedrill hole useless. The TUBEXXL method was developed bySandvik to solve this problem.TUBEX XL enables a uniqueform of simultaneous drilling andcasing, in which the hole is linedwith casing tubes as drillingproceeds. TUBEX XL equipmentis available for both tophammerand down-the-hole (DTH)drilling. It enables holes to bedrilled successfully through allkinds of overburden, even that inwhich boulders of varying sizesare suspended.

With the TUBEX XL method, thecasing tubes do not need to berotated during drilling. Instead,they are tapped down behind theTUBEX XL equipment, with theaid of a little percussion energyfrom the rock drill.

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PRINCIPLE OF OPERATION

The TUBEX XL method is basedon the principle of under-ream-ing, which makes it possible toinstall the casing tubes withoutthe use of rotation, at the sametime as the hole is drilled.

When rotation to the right (DTH)or left (tophammer) is engagedfor drilling, the reamer swingsout around the eccentric shaft ofthe TUBEX XL pilot bit. Thisenables it to ream a hole that isslightly larger than the outsidediameter of the casing tubes.Once the desired depth has beenreached, the direction of rotationis momentarily reversed, whichcauses the reamer to swinginwards around the eccentricshaft of the pilot bit. This enablesboth the pilot bit and reamer to bepulled up through the inside ofthe casing tubes, which remain inthe hole.

With the TUBEX XL equipmentremoved, it is possible to con-tinue drilling the hole through thebedrock, using conventionaldrilling equipment. To preventthe ingress of surface water, e.g.in water-well drilling, the casingtubes can be grouted into positionwhere they meet the bedrock. Inany event, they should be drivenfirmly down to the actual bottomof the reamed hole.

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WHEN IS TUBEX XL USED?

The TUBEX XL method can be used when anyof the following difficulties arise:

1 Whenever there is poor hole-wall stability,which calls for the use of casing tubes.

2 When the overburden contains stones andboulders.

3 In fragmented rock formations.

4 When drilling through land fill, rubbishdumps etc. of varying composition, e.g. wood,bricks, scrap iron.

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ADVANTAGES OF THETUBEX XL METHOD

1 The hole is cased at the sametime as it is drilled.

2 The equipment is designed todrill-and-case through thicklayers of overburden, which canvary greatly in composition.

3 The drilling and reamingequipment can be pulled up

through the casing tubes, whichmeans that:

- inexpensive casing tubes can beleft in the drill hole;

- drilling can be continued withconventional equipment afterthe casing tubes have reachedthe bedrock;

- it is possible to take continuoussoil samples.

4 Since the casing tubes are notrotated, only moderate rotationforces are needed.

5 TUBEX XL can be used onmost conventional drill rigs, eventhose that are small and simple.Adaptation for use with TUBEXXL is minimal and inexpensive.

6 TUBEX XL does not harm theenvironment.

7 TUBEX XL can be used onworksites where space is limited.

Example of typical TUBEX XL drilling:

A 1.5 m large stones

B 2.0 m boulder

C 5.0 m - moraine containing large stones

D 1.5 m - boulder

E 3.0 m - sandy moraine

F 1.0 m - boulder

G 5.0 m - coarse sand with transition to clay

H 10.0 m - very hard, stone-free clay

I 1.0 m - rock

K Bedrock

L 140 mm casing tubes

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The guide device (12) is joined tothe extension rods (6) via a shortextension rod (13) and a wingcoupling (9). A wing couplingshould also be connected at everythird or fourth joint in the exten-sion rods, particularly in the caseof TUBEX XL 127.

The TUBEX XL ”package”consists of five components: thepilot bit (10), reamer (11), guidedevice (12), short extension rod(13) and wing coupling (9).

A short ”bit tube” (14), which isof better quality than the rest ofthe casing tubes is used if neces-sary. It serves to protect the frontend of the casing tubes fromdeformation and wear.

The first casing tube (8), the star-ter tube, including a bit tube (14)

EQUIPMENT & FUNCTION

TUBEX XL equipment is avail-able for both tophammers andDTH hammers. TUBEX XL fortophammers is used mainly in theconstruction industry.

The greatest area of applicationfor TUBEX XL for DTH ham-mers is in the drilling of wells.

Tophammer equipment

In tophammer drilling, the drillstring is rotated to the left. Thecasing tubes are driven downwith the aid of percussion fromabove.

The percussion mechanism androtation unit are built into one unit(the rock drill), which is mountedon the feed (1). Flushing isintroduced separately, via theflushing device (3).

In the beginning, the casing tubes(8) sink into the drill hole bymeans of their own weight (invertical drilling). However, as thedepth of the hole increases, so thefriction between the casing tubesand the hole wall increases. Ittherefore becomes necessary toapply a small amount of percus-sion to the casing tubes. This isachieved by means of the shankadapter (2) and driving cap (5).The casing tubes are driven downwithout being rotated, at the sametime as the hole is drilled.

Between the shank adapter anddriving cap there is a spacer (4),which enables the wrench flat ofthe extension rod (6) to bereached. Between the driving cap(5) and casing tube (8) there is anadapter sleeve (7) for eitherwelded or threaded casing tubes.

if necessary, should be cut to alength (B) which, for TUBEXXL 76, should be equal to thetotal length of the first extensionrod (6).

In the case of TUBEX XL 127,the corresponding starter tubeshould be 520 mm longer thanthe total length of the firstextension rod.

Bear in mind that the effectivelength of the casing tubes thatfollow should always be the sameas the total length of the exten-sion rods.

Note also that the hole depth islimited because of energy lossesin the joints of the drill string andthe friction between the casingtubes and the hole wall.

Example:

First tube and rod Other tubes and rodsTubex 76 and 127 Tubex 76 and 127 *)

TUBEX Total length Total Effectivedim. Rod A Tube B rod length tube length

***)

1220 1220 1220 122076 *) 1830 1830 1830 1830

2435 2435 2435 24353050 3050 3050 3050

1220 1740127 **) 1830 2350

2435 29553050 3570

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E

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Reamer G- fitted with cemented carbide

buttons- swings out around the eccentric

shaft of the pilot bit- has a diameter marginally

smaller than the inside diameterof the bit tube

- when swung out into the rea-ming position, the reamer reamsa hole somewhat larger than theoutside diameter of the bit tube

Pilot bit H- fitted with cemented carbide

buttons- has eccentric shaft to accommo-

date the reamer- stop lugs limit the turning

movement of the reamer to 180°- has threaded shaft for attach-

ment to the guide device

Bit tube I

- internal diameter dimensionedto give minimal radial playbetween guide device and bittube

- protects the front edge of thecasing tube from deformationand wear

TUBEX XL FORTOPHAMMER DRILLING

Shank adapter A and B- transmits percussion energy to

the drill string (R 38) anddriving cap

- transmits rotation to the drillstring

Shank adapter A- R38, T38, or T45 shank adapter

with built-in separate flushingcan be used

- the shank adapter can be joinedto the R38 extension rod bymeans of a driving sleeve

Shank adapter B- R38 shank adapter with female

thread, intended for separateflushing

Driving cap C- transmits percussion energy

from the shank adapter to thecasing tubes

-collects the drill cuttings, whichcan be ducted away via a hose

Adapter sleeve D- transmits percussion energy

from the driving cap to thecasing tubes

- protects the rear edges of thecasing tubes from deformationand wear

Wing coupling E- centralizes the drill string inside

the casing tubes- fitted between the first and

second extension rods, and atevery third or fourth jointthereafter

Guide device F- has internal thread at both ends- centralizes the pilot bit and

reamer inside the bit tube- has grooves for the passage of

drill cuttings

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TUBEX XL FOR DTH DRILLING

In DTH drilling, the drill string isrotated to the right. The casingtubes are pulled down with the aidof percussion, which is transmittedvia a specially designed casingshoe (12).

Since drill tubes are used instead ofextension rods, only one guidesleeve (5) is needed, and this isplaced between the first drill tubeand the DTH hammer top sub.

The discharge head (4) works bothas a director for drill cuttings andas a guide for the drill tubes (3).

When the drill hole is started, thecasing tubes (7) sink by their ownweight. However, as the depth ofthe hole increases, so does thefriction between the casing tubesand the hole wall, which meansthat the casings have to be drivendownwards. The percussionmechanism is down the hole inDTH drilling, where it worksdirectly above the drill bit. For thisreason, the force needed to drivedown the casing tubes is transmit-ted via the casing shoe (12).

Considerably greater hole depthscan be achieved with DTH drilling,because percussion-energy lossesare very much lower than intophammer drilling.

The basic TUBEX XL ”package”consists of four components: thepilot bit (11), reamer (10), guidedevice (9) and guide sleeve (5).The shape and function of the pilotbit and reamer are basically thesame as for tophammer TUBEXXL, but the pilot bit has a right-hand thread.

The guide device (9) includes ashank for insertion into the DTHhammer, an impact shoulder fordriving down the casing tubes, anda connection thread for the pilot

bit. The function of the impactshoulder is to transmit percus-sion energy to a correspondinglip inside the the casing shoethat leads the casing tubes.

The flushing medium, whichconsists of exhaust air from theDTH hammer, is forced outthrough channels in the guidedevice, reamer and pilot bit. Thedrill cuttings are led via flushinggrooves in the guide device, upthrough the annulus between thedrill tubes and the casing tubes.They are collected at the dis-charge head (4), which sits ontop of the casing tubes, anddiverted through an elbow into adischarge hose.

In horizontal drilling, e.g.through road and rail embank-ments, where there is a greatdemand for straight holes, theroad- embankment bit (13) isrecommended instead of theeccentric pilot bit and reamer(11 and 10). The road-embank-ment bit, which is of the full-face type, can be used for”breakthrough” drilling only,i.e. when the drill bit re-emergesat the other end of the drill hole.

Note that the road-embankmentbit must be removed before thedrill string can be pulled backthrough the casing tubes.

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4/157TUBEX XL FOR DRILLINGWITH DTH HAMMERS

Guide sleeve A- for centralizing the drill string

inside the casing tubes- placed between the DTH

hammer and the first drill tube

Guide device B- centralizes the pilot bit and

reamer inside the casing shoe- transmits percussion energy

from the DTH hammer to thecasing tubes, via the casingshoe. The percussion energyserves to drive down the casingtubes.

- has spirally milled flushinggrooves to conduct the drillcuttings into the annulusbetween the drill tubes and thecasing tubes

- the shank of the guide deviceconnects the TUBEX XLpackage to the DTH hammerand transmits percussion energyfrom the hammer to the pilot bitand reamer

Reamer C- is fitted with cemented carbide

buttons- turns around the axis of the

eccentric shaft of the pilot bit- has a diameter marginally

smaller than the internal diame-ter of the casing shoe

- when swung out on the eccentricshaft, it reams a hole some-whatlarger in diameter than theoutside diameter of the casingtubes

Pilot bit D-is fitted with cemented carbide

buttons- has an eccentric shaft to accom-

modate the reamer- has stop lugs that limit the

turning movement of the reamerto 180°

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Casing tubes

The recommended casing tubesare listed in the table on page 32.

The first casing tube is called thestarter tube. It is the tube to

which the casing shoe is welded,and must therefore be cut tolength (J), as follows:

A. The length of that part of the casing shoe whichslides inside the starter tube

B. The length of the impact shoulder on the guidedevice

C. The effective length of the DTH hammer

D. The effective length of the guide sleeve

E. The effective length of the drill tube

F. The effective length of any additional sub(if used)

Sub Total 1

Step 2 Add up the following measurements:

G. The length of the discharge head, measured fromthe inner shoulder to the upper part

H. Extra addition (min. 75 mm)

I. The length from the shoulder of the drill tube to thelower edge of the wrench flats (or, if there is anarrowing of the drill tube beneath the wrench flats,to the point where the tube regains full diameter)

Sub Total 2

Step 3 The length (J) of the starter tube is obtained bysubtracting Sub Total 2 from Sub Total 1.

Note that if a shorter starter tubeis required, the measurements forA, B, C, D and F are added up.Sub Total 2 is then subtracted.

Note also that lengths of thecasing tubes that follow shouldalways be the same as the effecti-ve lengths of drill tubes withwhich they are used.

- has a threaded shaft for scre-wing into the guide device

Casing shoe E- is welded to the front of the

leading casing tube- transmits percussion energy

from the guide device to thecasing tubes

- centralizes the guide deviceinside the casing tubes

- protects the front edge of thecasing tubes from deformationand wear

- the outside diameter of thecasing shoe is the same as theoutside diameter of the casingtubes

Threaded casing tubes F- used when you wish to pull up

and re-use the casing tubesshould be seamless tubes that

meet the relevant specificationsregarding quality and thickness.

- should be suitable for re-use, i.e.they should have hardenedthreads

- male and female, right-handthreads for TUBEX XL 76 and127 for tophammer drilling

- male and female, left-handthreads for TUBEX XL 90 andupwards, for DTH drilling

- must be flush joint

Welded casing tubes G- should be seamless tubes that

meet the relevant specificationsregarding quality and thickness.Should be suitable for welding,i.e. the C content should be low(0.10 - 0.15)

- the preparation of joints forwelding is done with the aid ofspecial tools

Road-embankment bit H- has cemented carbide buttons- has full-face type bit head -threaded shaft for screwing into

the guide device

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TUBEX XL 76 127 90 115 140 165 190 215 240 280 365

Difference indiameter, mm 2 2 2 2 6 4,5 4 5 4 5.5 6

Bevelling/chamfering

In order to produce a weld ofgood strength, the lower end ofthe casing tube should be bevel-led, as shown in the figure on theleft. Alternatively, the ends ofboth casing tubes can be bevel-led, as shown on the right. Thebevelling can be carried out usinga special bevelling grinder, whichrotates around a fixture that iscentralized inside the casing tube.The bevelling grinder is poweredby compressed air, and is veryeasy to operate in the field.

further penetration impossible.

Recommended tolerances:

Outside diameter of casing tube:± 1%

Thickness of casing tubes: ± 10%

Tensile strength of casing tubes:≥ 35 kp/mm2

The difference in diameterbetween the guide device and thecasing tubes should not be lessthan that shown below.

welded joints with excessive beadpenetration can prevent theTUBEX XL equipment frombeing pulled up through thecasing tubes.

The outside diameter of thecasing tubes is also of greatimportance. Tubes with an ODthat is altogether too big will runthe risk of getting stuck in thehole, since the diameter of thereamed hole will not be largeenough to accommodate them. Inthis case, clearance around thecasing tubes would perhapsdisappear completely, making

The thickness of the casing tubesshould not be less than thedimensions given in the table onpage 32. The smallest permissiblediameter for the casing tubes isdetermined by the greatestdiameter on the guide device.

If the tolerance between the guidedevice and the casing tubes isaltogether too small, there is arisk that the guide device will jaminside the casing tubes when theTUBEX XL equipment is with-drawn. Dents in the casing tubes,(oval) deformation, or poorly

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It is very important for the cut tobe made at perfect right angles tothe centre line of the casing tube.

Joining casing tubesDo not drill the casing tube toofar into the ground when joiningis to take place. It is much easierto make the joint above the drill-steel support, at a convenientheight. This lets you lift up thenext tube easily, and weld in acomfortable position.

A drill tube must be inserted intothe new casing tube before it islifted up. The two componentsare then lifted up together, andthe drill tube is threaded intoposition. Now the ends of thecasing tubes can be positioned forwelding. Make sure you line upthe casing tubes perfectly beforestarting to weld. Place spacersbetween the two casing tubes, sothat you get a suitable gap(approx. 2 mm) for welding.

Fix the casing tubes into positionwith the aid of a welding fixture,or clamp. Tack weld in four

Cutting

Casing tubes can be cut at theworksite by means of any of thefollowing:

produce a bead with good pene-tration, and without pores. Grindthe outside of the weld so that itis flush with the casing tubes.Weld the casing tubes accordingto the instructions that follow.

places around the joint, at 90°intervals. Then weld carefully to

General comments on welding=A simple welding fixture helpsto keep the new casing tube inperfect alignment with the rest ofthe casing string. This is essentialfor problem-free drilling.

The weldability of the casingmaterial is usually good. Ifwelding is carried out correctly,then hardening or embrittlementshould not occur either in theweld itself or in the zones that areaffected by heat. However, thereis a risk of hot-crack formation inmaterials with comparativelyhigh sulphur and phosphorouscontents.

Welding must not be carried outwhen there is snow, frost or dampin close proximity to the joint thatis to be welded. Before welding,substances such as oil, paint etc.should be removed from thewelding surface and surroundingzone. If this is not done, there is ahigh risk of porosities in theweld. In order to avoid the risk ofembrittlement and subsequentfracture, it is recommended thatthe temperature of the material tobe welded should be above 0° Cwhen welding begins.

- gas torch- a hand held pneumatic grinder- a chain knife (tube cutter).Comments on the above alterna-tives are as follows:It is difficult to get a clean, right-angled cut when using a gas torch.

The hand-held pneumatic grinderis not precise. The chain knife(tube cutter) is the best choice,because it gives a perfect, right-angled cut.

If the casing tubes were orderedfrom the supplier in specifiedlengths, they will have been cutby machine with great precision.Cutting at the worksite will benecessary only if a welded stringof casing tubes is to be taken upand re-used.

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Welding method

Manual metal-arc welding (com-monly called arc welding) isrecommended for the welding ofcasing tubes, using coated electro-des. A welding machine poweredby a combustion engine orhydraulic motor is recommendedfor use in the field.

Electrodes

Basic, normal yield electrodesshould be used. The electrodetypes listed below (or equivalentelectrodes of other makes) arerecommended:

- ESAB OK 48.00- Philips 35- Oerlikon Supercord- Arcos Ductilend 70

The above electrodes meet thespecifications in ISO E-445 B 20.The nominal weld metal analysisis C = 0.1%, Si = 0.7%, Mn =0.7%. The yield point of the welddeposit is greater than 400 N/mm2

(40 kp/mm2) and its ultimatetensile strength is greater than 500N/mm2 (50 kp/mm2).

It is very important that basicelectrodes are stored in such a waythat the flux coating does not absorbmoisture from the atmosphere.Electrodes should therefore bestored in the sealed plastic wrappingin the box in which they weresupplied, or in some other way thatprevents damp penetration.

Welding procedure

Joint preparation shall be carriedout as shown in the figure onpage 12. Under worksite condi-tions, bevelling can be carriedout by means of gas cutting,manual grinding or semi-automa-tic grinding. The latter method,for which a special tool isavailable, is recommended. Thecasing tubes are fixed intoposition by means of a specialfixture. It is recommended thatwelding be carried out using

electrodes with a diameter of 2.5mm, at approx. 85 A. Leave a 2mm gap between the casing tubesto facilitate welding. The weld-ing sequence is shown below.

Demands on the weld

The weld should be of goodstrength, which requires full beadpenetration with no significant

inclusions or pores, and noembrittlement either in theweld itself or in the zonesaffected by the heat of theweld.

The depth of bead penetrationshould not exceed 0.5 mmbeyond the internal diameter ofthe casing tube. The height of theweld on the outside of the casingtube should not exceed 2 mm,and should be ground down.Grinding on the casing tubesshould be carried out in thelongitudinal direction only.

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Scratches caused by grindingacross the longitudinal axis of thecasing tubes should be avoided,so as not to impair the strength ofthe weld.

If the height of the weld is notground down, problems couldarise when drilling throughboulders.

Similarly, if bead penetration isexcessive, jamming could occurwhen TUBEX XL equipment ispulled up through casing tubes.

Welding casing shoe & bit tube

The casing shoe serves both tocentralize the TUBEX XLequipment inside the casing tubesand to receive the percussionenergy that drives down thecasing tubes. For this reason, thequality of the weld which joins itto the leading casing tube is veryimportant.

The casing shoe must be alignedcarefully so that it is located

concentrically inside the leadingcasing tube. The centre line of thecasing shoe must be absolutelyparallel to that of the casing tube.To increase the area of the weld,

you can make slits or holes at theend of the casing tube.

When deep holes are to be drilledwith TUBEX XL, it is veryimportant to use genuine SandvikCoromant casing shoes. Sandvikcasing shoes are made of steelwith high fatigue strength and areespecially hardened for thispurpose. Poor quality material in acasing shoe will wear out beforerequired hole depth is reached.

The casing shoes and bit tubeshave internal diameters to suit therespective guide devices fordifferent sizes of TUBEX XLequipment. There should be aslittle play as possible between theguide device and the casing shoeor bit tube. Excessive play couldresult in the reamer not beingable to ream a hole sufficientlylarge for the casing tubes. Thiscould result in the casing tubesgetting stuck, which wouldprevent them from being drivendown to the desired depth.

TUBEX XL casing shoes and bittubes are made of a material thatmeets SIS 2225 or DIN 17200(25 Cr, Mo4).

Steel of this quality should not bewelded at low temperatures. Inorder to obtain a satisfactoryweld, the casing shoe or bit tubeshould first be heated up to atemperature of 150-200° C.Ideally, welding should be carriedout in a workshop.

A special electrode should beused for the welding of casingshoes and bit tubes.

1 Heat up the casing shoe orbit tube to 150-200° C.

2 Fit the welding fixture andline up the two ends thatare to be welded.

3 Use OK 78.16 weldingelectrodes or equivalentelectrodes of another make.

Use a 2.5 mm electrode forthe bead weld, and a cur-rent strength of 75-100 A.4 Start by tack welding, as

illustrated on page 14.5 Remove the welding

fixture.6 Fill the joint with another

1-2 weld runs, using a 2.5or 3.25 mm electrode.

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TUBEX XL User’s handbook4-

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Step 1 Add up the followingmeasurements:

When welding is finished, theweld must be ground to make iteven. This will reduce the frictionbetween the casing tubes and the

hole wall as the tubes are drivendown. Use the same grindingmachine as for bevelling. Grindonly along the longitudinal axisof the tube. Scratches caused bygrinding across the longitudinalaxis of the tube can cause increa-sed tension in the joint. Grinduntil the surface across thewelded joint is flat.

DRILLING PROCEDUREWhen it comes to the actualdrilling method, the following tipsshould be taken into considerationfor all TUBEX XL equipment.

High penetration rates shouldnot be a dominating factor. Itcan be all too easy to obtain rapidpenetration in the soft formationsin which TUBEX XL is oftenused. However, rapid penetrationcan have a negative effect oncuttings removal, which can leadto difficulties in closing thereamer when the time comes towithdraw the the TUBEX XLequipment from the hole. Theobjective should rather be tomaintain constant cuttingsremoval and to avoid blockages.Rotation and penetration should

therefore be as smooth and evenas possible.

To close the reamer, reverserotation of the tophammer orrotation device should be sudden,short and intensive. The operatorshould be aware that it is possibleto unthread the pilot bit duringthis operation, which would resultin both the pilot bit and thereamer being lost down the hole.Reverse rotation should thereforebe applied for a maximum of onerevolution only.

If the reamer does not close, thiscould be due to:

A Uncleared drill cuttingspreventing the reamer fromclosing.

B Conditions are such that thesurrounding material is not givingany resistance to the reamer.

Action:

A Switch on the flushing(without drilling) for a fewminutes, increasing the air orwater pressure if possible. Tryclosing the reamer again.

B Lift the TUBEX XL drillstring so that the upper edge ofthe reamer comes into contactwith the underside of the casingshoe or bit tube. Apply reverserotation carefully and see if thiscauses the reamer to close.

C Continue drilling and casinguntil more favourable material isreached.

Important points when drillingwith TUBEX XL for DTHhammers

1 Use low pressure whendrilling through easily drilledmaterial.2 When drilling throughconglomerate and clay, reducethe air pressure and increase therotation speed.

3 If threaded casing tubes areto be re-used, make sure that theyhave hardened threads.

4 Correct welding of the casingtubes is very important, owing totensile stress in the weld. Followthe instructions given.

5 The wall thickness of thecasing tubes should not be lessthan that given in the table onpage 32.

6 N.B. Before continuing todrill with conventional rockdrilling equipment, the guidesleeve above the DTH hammermust be removed. This is becauseits diameter is greater than thediameter of the impact shoulderinside the casing shoe.

7 In the case of continueddrilling, the diameter of thestandard drill bit must be lessthan the smallest inside diameterof the casing shoe (see table onpage 32).

8 Most DTH hammers have anexchangeable choke plug. A solidchoke plug is used when maxi-mum piston energy is required.For TUBEX XL drilling, it isrecommended that a bored chokeplug be used in order to obtainthe best flushing and cuttingsremoval. The size of the hole inthe choke plug should be matchedto the compresssor's capacity.

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9 Make sure that the checkvalve of the DTH hammer closesand seals tightly. A leaking checkvalve can cause dirt and impuri-ties to enter the rock drill whenthe air supply is switched off.This is of the utmost importancewhen drilling in heaving forma-tions such as quicksand. Forincreased safety in difficultconditions such as these, it can beadvisable to install an extra checkvalve either in the guide sleeve orin one of the drill tubes.

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10 The drill tubes should alwaysbe handled and stored so that theyremain clean on the insides.

11 If the TUBEX XL equipmentis to be left in the drill hole forlonger periods of time, it isrecommended that the pilot bitand reamer are drawn up insidethe casing tubes. This is especial-ly important in heaving forma-tions.

12 Before starting each newhole, it is very important to checkthe wear on the reamer. Theeasiest way to do this is with theaid of a straight rule. The reamermust always produce a hole ofgreater diameter than the outsidediameter of the casing tubes.

13 If a pilot bit pin is used(TUBEX XL 140 and upwards),make sure that it is undamagedbefore starting each new hole.

Pilot pin

AA

A-A

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173

TUBEX XL 140 and largerdimensions are equipped with athrough hardened pilot bit pinthat is held in place by a self-locking spring pin. The mainfunction of the pilot bit pin is toprevent the pilot bit from un-screwing when drilling in soft

4/171 E

Top subO-ring

Check valve Dart

Check valvespring

Check valveguide

Make-upring

Choke plug

Rigid valve

O-ring

Pistoncase

Piston

Pistonretainerring

O-ringBitretainerring

O-ring

Driversub

and cavitied formations, i.e.formations that do not givesufficient resistance to the blowsfrom the hammer (idle blows).When closing the reamer, it isvery important to reverse rotateonly one revolution at a time, inorder to avoid fracturing the pilotbit pin. Check that the pilot bitpin is undamaged before startingeach new hole.

Preparations for drilling

First assemble the DTH hammerand TUBEX XL equipment. Thentake the first casing tube, towhich the casing shoe has beenwelded, and insert the TUBEXXL equipment together with theDTH hammer. The reamer mustof course be closed completely.Do not rotate the drill tube, or thereamer will expand inside thecasing tube.

20

TUBEX XL User’s handbook4-

2/17

4

With the larger TUBEX XLvariants (140 and upwards), theDTH hammer is suspended in therotation device. The casing tubeis set on the ground, and the DTHhammer and TUBEX XL equip-ment is lowered carefully into thecasing tube. If the TUBEX XLequipment does not pass throughthe casing shoe, try to centralizethe casing tube with the aid of alever or some other implement.Under no circumstances should

the rig so that the drilling equip-ment slides into it.

Discharge head

TUBEX XL drilling takes placewith the discharge head restingon top of the casing tubes.Without the discharge head, thedrill cuttings would be sprayed allover the rig, the operator, adja-cent buildings and anything elsein the vicinity. With the dischargehead fitted into place, the drillcuttings can be led away to acontainer or suchlike, and it iseasy to take samples of thecuttings during drilling. And byusing the discharge head, you

the percussion mechanism of theDTH hammer be used to get theTUBEX XL equipment throughthe casing shoe! At worst, thiscould result in the equipmentjamming inside the casing shoe,which would then have to be cutopen in order to remove theTUBEX XL equipment.

Alternatively, the rig’s winch canbe used to slide the casing tubeover the TUBEX XL equipmentand DTH hammer. With thecasing tube and drilling equip-ment lying on the ground in frontof the rig, the winch cable isattached to the casing tube. Thecasing tube is then pulled towards

will not have to wash down anybuildings etc!

Tube handling

Take care when handling thetubes, in order to avoid denting ordeformation of the tube ends. Adented tube can cause theTUBEX XL equipment to jamwhen you try to pull it up throughthe casing tubes.

4/175

To make tube handling easier, itis useful to have two A-trestles,across which the casing tubes(with drill tubes inserted) can belaid. The ends of the drill tubesshould be fitted with protectivecovers to prevent dirt and waterfrom entering the tubes. Protecti-ve covers protect not only thethreads of the drill tubes, but

4-2/

176

ultimately the internal compo-nents of the DTH hammer aswell.

Handling of longer tubes

It is best to use the rig winchtogether with a special liftingsling for tube handling.

Attach the lifting sling to thecasing tube, and then insert thedrill tube into the casing tube.

21


4/178

4/179

4/180

4/181

tube that is already embedded inthe ground.Apply slow rotation, to thread thedrill tubes together.

Fit the discharge head on to thedrill tube and, with the aid of thewinch, lift the entire assembly upthe feed beam.

Thread the drill tube securely intothe spindle of the rotation unit.

Lower the casingtube so that itrests on the edgeof the drill steelsupport, andremove the lower

part of the liftingsling.

Lift the casingtube so that ithangs directlyabove the casing

Fix the casing tubes end toend, with the aid of thewelding fixture (page 14).

4-2/

177

22


4/1834/182

Setting up the drill rig

In order to obtain the greatestpossible hole straightness, it isimportant that the drill rig beproperly set up to ensure stability.

All unintentional movements ofthe feed beam or drill rig willcause deviation between theoriginal and final angle of thedrill hole. Such deviations lead tocrooked holes, jammed equip-ment, difficulty in joining casingtubes etc.

At worst, the casing tube stringcould break, which would make itimpossible to withdraw thedrilling equipment from the hole.

Drilling

Before drilling is started, the pilotbit must be screwed securely intothe guide device (with the aid of abreakout wrench). Once this hasbeen done, the pilot bit pin shouldbe inserted (TUBEX XL 140 andupwards). The joints between thedrill tubes must also be properlytightened before drilling isstarted. This should ensure thatthe drill string does not uncouplewhen reverse rotation is appliedfor the purpose of closing thereamer and pulling up theTUBEX XL equipment.

Make sure that the casing tube isproperly guided in the drill steelsupport. Collar the hole carefully,using reduced percussion pressu-re and reduced feed pressure. Liftthe equipment regularly, andflush out the hole. This willprevent the flushing holes in thepilot bit and the flushing groovesin the guide device from beco-ming blocked.

Once the casing tube has penetra-ted the ground by about 1 meteror so, you can switch over tonormal percussion pressure (up to14 bar) and feed force. Youshould still stop drilling from

4/183

23


4/185

4/184

lifting the tubes frequently andflushing out the hole.

Before drilling is discontinued forany length of time, the holeshould be flushed out thoroughlyto remove any drill cuttings. Ifdrilling is discontinued withoutflushing the hole properly, drillcuttings can drop to the bottom ofthe hole and jam the DTHhammer in the hole.

When drilling is to be startedagain after a stoppage, alwaysbegin by flushing out the hole.

Telescopic drilling

By starting TUBEX XL drillingwith a large diameter and gradu-ally changing to smaller sizes ofTUBEX XL, great hole depthscan be achieved.

Possible TUBEX XLcombinations intelescopic drilling:

365-240-190-140-90

365-280-215-165-115

365-280-215-140-90

time to time, just to clean out thedrill hole. Frequent flushingmakes a clean drill hole andprevents blockages!

In clay formations, the use offoam makes drilling easier(see the chapter on foam drilling,page 29).

Lift the casing tubes from time totime to make sure that theyalways slide freely inside the drillhole. If this is not done, there is arisk that the tubes will break atthe first joint if you pass througha clay zone and then continuedrilling in softer rock formations.

IMPORTANT: Keep the casingtubes as ”free” as possible insidethe hole. This can be done by

Example:

TUBEX XL 215 50metresTUBEX XL 165 60metresTUBEX XL 115 70metresDTH drilling 100 metres

Total 280metres

24


2 614

16

0

8 10 1218

20

BAR

4/186

Recommended drilling data

TUBEX XL equipment is bestsuited for air pressures between12 and 14 bar. In order to obtainthe best service life for TUBEXXL equipment and avoid damage,the air pressure should not exceed14 bar.

Suitable rotation speed dependson the size of TUBEX XL beingused, and on the characteristics ofthe rock formation.

The table below gives guidingvalues.

The speed of rotation should beset according to the frequency ofthe DTH hammer and the diame-ter of the reamed hole. Therotation speeds given above referto drilling in rock. When drillingin fragmented rock, clay and softmaterials, higher rotation speedsare needed.

TUBEX XL 76 90 115 127 140 165 190 215 240 280 365Rotational torqueminimum(Nm) 800 900 2000 2000 3000 4000 >6000 >6000 >6000 >10000 >10000

Possiblehole depth(m) 40 60 100 40 100 100 100 100 100 100 100

Rotational torque

It is important that the drill rig beequipped with a rotation motor ofsufficient torque, especially whendeep holes are to be drilled withthe TUBEX XL method.

The hole depths given should be

regarded as nominal hole depthsfor the respective sizes ofTUBEX XL equipment. Inpractice, it is the characteristics ofthe overburden that will deter-mine the maximum hole depth.Obviously, greater hole depths

can be achieved if powerful drillrigs are used for easily drilledformations. Bear in mind that thefeed motor of the drill rig shouldhave sufficient capacity to lift upall the drilling equipment.

TUBEX XL 76 127 90 115 140 165 190 215 240 280 365

Rotation speed 50- 15- 20- 20- 15- 15- 10- 10- 10- 10- 10-(RPM) 70 25 30 25 20 20 15 15 15 15 15

25


m3/min - m/s - FPM

Use the diagram to determine theflushing velocity when the holediameter, drill tube diameter andair volume are known. Follow thevertical line from the hole diam-eter(TUBEX XL size) until you meetthe line for the size of drill tubethat you are using. Then gohorizontally to the vertical linefor existing compressor capacity.The meeting point gives theflushing velocity with the aid ofthe diagonal lines, which showdifferent flushing velocities.

Flushing velocity

In order to lift the drill cuttingsefficiently to the surface, thevelocity of the flushing mediumin the annulus between the drilltubes and casing tubes should beat least 20 m/s (about 4000 FPM).Velocity depends on the capacityof the compressor and on the sizeof the annulus between the drilltubes and casing tubes. The drilltubes should not be thicker thanthe outside diameter of thehammer. The formulae on page25 are used to calculate theflushing velocity in m/s.

4/187 E

2000 1800 1600 1400 1200 1000 800 600 400 200 0 -200

AIR VOLUME

2 3 4 5 6 7 8 9 1

0

1

1

1

2

1

3

1

4

HOLE DIAMETER

DRILL TUBES

9"

4 1/2"

4"

3"

2"

5000 4000 3000 2000

6000

7000

8000

9000

10000

M /MinCF

M

INCHESM

M

56.6 50.9 45.3 39.6 34.0 28.3 22.6 17.0 11.3 5.7 0 -5.7

5

1

7

6

102 127 152 178 203 229 254 279 305 330 356

229 mm

10"254 mm

8"203 mm

7"178 mm

6"152 mm

5"127 mm

115 mm

102 mm

76mm

51mm

10.215.220.3

AIR VELOCITY25.4

30.5

35.6

40.6

45.7

50.8

TUBEX 90TUBEX 115

TUBEX 140TUBEX 165

TUBEX 190TUBEX 215

TUBEX 240

M/SFPM

3

A B

4-2/187E

Example:

If you are drilling a 5" hole(TUBEX XL 115) with 3"drill tubes and a compressorcapacity of 14 m3/min: followthe hole-diameter line up to“3-inch drill tubes” (A); movehorizontally to the line for “14m3/min” air volume (B). Theflushing velocity can be readaccording to the diagonal lineat the meeting point (B) -about 28 m/s. When conver-ting to FPM, 1.0 m/s isequivalent to about 197 FPM.

26


HOLE DIAMETER

2600 2400 2200 2000 1600 14001200 1000 800 600 400180073.6 67.9 62.3 56.6 45.5 39.6 34.0 28.3 22.6 17.0 11.350.9 M /Min

CF

M

3

152 mm 6"178 mm 7"203 mm 8"229 mm 9"254 mm 10"

127 mm 5"

178 203 279 305 330 356 381 406 432 457 4837 8 1

2

1

3

1

4

1

5

1

6

1

7

1

8

INCHESM

MTUBEX 280 TUBEX 365

1526

2299

2541

0

1

1

1

9

AIR VOLUME

AIR VELOCITY

DRILL TUBES

10.22000

15.23000

20.34000

25.45000

M/SFPM

4-2/188E

4/188 E

27


rotation for a maximum of onerevolution. Now try to lift thedrill string. If the TUBEX XLequipment does not enter thecasing shoe, apply rotation (as fordrilling) for a few revolutions,and repeat the procedure, i.e.generous flushing followed byreverse rotation (max. 1 rev.).N.B. The shaft of the pilot bit isthreaded into the guide device byabout 2.5 turns. If for somereason the pilot bit loosens in theguide device, then too many turnsin reverse rotation will risk losingboth the pilot bit and the reamerdown the hole.

Termination of TUBEXXL drilling

When the casings are drivendown to the desired depth and theTUBEX XL equipment is pulledout of the hole, the bottom end ofthe casing string should be fixedinto position. In water-welldrilling, the bottom end of thecasing string is usually groutedinto position.

Formulae for calculation of flushing velocity

DH

2 - DP

2

2/19

0

Withdrawal ofTUBEX XL equipment

Once the casing tubes have beentaken down to the desired depth,TUBEX XL drilling is stoppedand the equipment is pulled upthrough the inside of the casingtubes.

Start by flushing out the drill holethoroughly, at the same timerotating the drill string as fordrilling. Lift the drill stringslightly, until the reamer meetsthe underside of the casing shoe.Then lower the drill string byabout 10 mm and apply reverse

DH

2 - DP

2

Flushing velocity (m/s) = F x 21220

F = Free air consumption (m3/min)

DH

= Inside dia of casing tube (mm)

DP

= Outside dia of casing tube (mm)

Flushing velocity (m/s) = F x 1273

F = Free air consumption (l/s)

DH

= Inside dia of casing tube (mm)

DP

= Outside dia of casing tube (mm)

28


AA A-A

4/191

4/192

Start by pulling up the casingstring by about 10 cm. Then (forTUBEX XL 115) pour about 10litres of cement grout into thehole. To obtain an effective seal,the cement can be pressed uparound the outside of the casingtubes, with the aid of a specialtool.

Finally, knock the casing tubesdown to the bottom of the reamedhole.

In certain cases it is not necessaryto grout the casing tubes intoposition upon termination ofTUBEX XL drilling. The casingtubes are simply driven down asfar as possible by striking theupper edge of the tubes with thehammer.

Breaking the joints inthe TUBEX XL equipment

The drill rig should be equippedwith a breakout cylinder tofacilitate uncoupling of the jointsin the TUBEX XL equipment.The breakout procedure can bedivided into three steps:

1 If a pilot bit pin has been used(TUBEX XL 140 and upwards),it must be tapped out togetherwith the self-locking spring pin.This is done using a punch, and itmust be done before any attemptis made to break the joint be-tween the pilot bit and the guidedevice.

2 Loosening of the pilot bit- place the bit wrench in the drill-steel support and locate theflushing grooves of the pilot bitso that they fit into the lugs in thebit wrench.- put the guide-device wrench in

29


4/103

4/193

4/194

place, at the top of the guidedevice- engage the feed to press theDTH hammer downwards, so thatthe tools are located into position- attach the breakout cylinder tothe guide-device wrench- break the joint between the pilotbit and the guide device.

3 Loosening the guide device- place the guide device supportin the drill-steel support andcentralize the guide device overthe shaft on the support- place the guide device wrenchat the top of the guide device- engage the feed and press theDTH hammer downwards so thatthe tools are fixed into position- fit a breakout wrench around thecasing of the DTH hammer- break the joint in the bottom subof the DTH hammer with the aidof the breakout cylinder.

If the drill rig is intended forlarger TUBEX XL equipment, itwill probably be equipped with ahydraulic breakout table and anadjustable chain tongue. Theequipment will make all breakoutoperations easier.

30


4/195

4/196

4/197

Continued drilling withTUBEX XL

If, for some reason, you need towithdraw the TUBEX XLequipment from the hole beforereaching the desired depth, youshould observe the followingbefore putting it back down thehole:

- make sure that the reamer canbe opened (swung out) withoutjamming

- check that the flushing holes inthe pilot bit are not blocked

- check the wear on the cementedcarbide buttons, and regrind ifnecessary

- check the wear on the reamer(see page 17)

- replace defective components,e.g. the pilot bit pin (TUBEXXL 140 and upwards).

When putting the TUBEX XLequipment back down the hole:

- do not rotate the drill string untilthe reamer has passed throughthe casing shoe! If the reamergets stuck in the casing shoe,you might have to withdraw theentire string of casing tubes.

- do not use percussion to helpthe reamer through the casingshoe!

- if the casing tubes have beenknocked down so that they areresting on the bottom of thereamed hole, they must bepulled up by about 20 cm beforethe TUBEX XL equipment isput back down the hole.

Continued drilling withregular DTHOnce the casing tubes are inplace, and possibly grouted intoposition, drilling continues usingan ordinary DTH drill bit. Great

care must be taken when passingthe DTH drill bit through thecasing shoe, since the cementedcarbide buttons can be easilydamaged by the impact shoulderin the casing shoe. Damagedbuttons and fragments of cemen-ted carbide in the drill hole cancause even the next drill bit to berendered unserviceable after onlya few metres of drilling. TheTUBEX XL ”size” gives themaximum diameter of the DTHdrill bit that can pass through thecasing shoe, e.g. TUBEX XL 140= ordinary DTH drill bit, max.140 mm in diameter.

The diameter of the DTH drill bitshould be greater (by approxima-tely 10 mm) than that of the pilotbit. Otherwise there is a great riskthat the DTH drill bit will jam inthe pilot hole, which could resultin damage to the peripheralbuttons. The first 20 cm shouldbe drilled with very slow rotationand reduced percussion pressure.When the pilot hole has beendrilled out, the feed, rotation andpercussion pressures can beincreased to the normal values.

To minimize the risk of jammingin the pilot hole, you could throwsome small stones into the drillhole, to fill up the pilot holebefore drilling.

31


N.B. The guide sleeve used inTUBEX XL drilling must beremoved from the top sub of theDTH hammer before normaldrilling can continue. This isbecause its outside diameter isgreater than the inside diameterof the casing shoe.

- Reduced flushing air require-ments when using air flushing.

- More efficient flushing in frontof the pilot bit and reamerreduces wear to the TUBEXXL equipment and gives moreuniform penetration.

- Foam ”lubricates” the drillstring and casing tubes, whichresults in less wear and a lowerrotational torque requirement.

- Foam lubricates and stabilizesthe hole wall, which helps thecasing tubes to slide moreeasily. This enables the casingtubes to be driven even deeper.

- Foam seals cracks and smallercavities, which helps tomaintain flushing efficiency.

- Foam breaks up clay and drillcuttings.

- Foam moistens and binds eventhe smallest of particles, e.g.drilling dust when drillingthrough rock.

Check that the foam rises evenlyand steadily out of the holeduring drilling.

If the foam spurts out of the holeerratically, it is an indication thatthe ”column of foam” in the holeis not filling the hole. This can beremedied by increasing thevolume of foaming concentrate.If the foam is thin and watery,and does not succeed in carryingthe drill cuttings, simply increasethe volume of foam concentratein the foam/water mixture.

Tophammer drilling

The use of foam flushing incombination with a tophammerand shank adapter for separate

Foam flushing

It is not essential to use foamflushing with the TUBEX XLmethod. Depending on theground conditions, either conven-tional air flushing or air/waterflushing can give satisfactoryresults.

However, foam flushing hasmany significant advantages,especially when problems occurwith the removal of drill cuttings,e.g. in clay formations and inwater-bearing strata. The advan-tages of foam flushing could besummarized as follows:

flushing does not call for additio-nal comment. The best foamconsistency is obtained at aflushing air pressure of 3-4 bar,although the operator should nothesitate to increase the pressure ifhe considers it necessary tomaintain efficient drilling.

DTH drilling

When foam flushing is used inDTH drilling, the foamingconcentrate is mixed with thecompressed air supply to the rockdrill. This means that it passesthrough the hammer itself.Experience has shown that thiscan be done without damagingthe hammer. The foaming con-centrate has built-in lubricatingproperties, which prevent siezingin the rock drill. N.B. The lubri-cating device for the rock drillshould be disconnected, or oil inthe air will break down the foam.When you are finished drillingwith foam, pour a little lubrica-ting oil into the drill string and letthe hammer run for a few min-utes, before pulling up the drillstring.

N.B. you should remember to re-connect the lubricating devicewhen returning to ordinary airflushing.

The simplest way of all to obtainfoam flushing is to pour a littleordinary dish-washing liquid intothe water tank. Alternatively, youcould simply mix water and dish-washing liquid in a bucket andpour it directly into the drillstring.

This very simple method willsolve problems when drilling insticky conditions.

4/198

32


than cemented carbide, especiallyon the reamer. This is quite naturalwhen drilling in soft overburden.The greatest wear occurs whendrilling through sand and gravel.

4/200

400-1200 m

200-600 m

100-300 m

4/199

OTHER COMMENTS

Equipment lost downthe hole

It is necessary to make fishingtools to retrieve components thathave been lost down the hole.The design and shape of a toolwill depend on what kind ofcomponent has been lost downthe hole, what kind of formationyou are drilling in etc.

The fishing tool should be shapedso that it can attach itself to theinside of the component that hasbeen lost down the hole.

For small steel components, amagnet attached to the end of alength of wire can be a usefultool.

When drilling through softoverburden, it is sometimespossible to force the lost compo-nent aside and continue drillingwithout further stoppage.

Tophammer drillingexceptions

Most information for TUBEX XLdrilling with DTH hammers alsoapplies to tophammer drilling.However, there are some differ-ences, the most important ofwhich are as follows:

- the casing tubes are drivendown by blows from the top ofthe string

- there is no casing shoe- hole depth is more limited

Wear and service life

Wear patterns on TUBEX XL bitsshow that body steel wears faster

Different components in theTUBEX XL package have diffe-rent service lives. A rough rule ofthumb is that two reamers are usedto one pilot bit, and two pilot bitsare used to one guide device.

Certain parts of the pilot bit,reamer and guide device aresubjected to more wear thanothers. It is important to keep aclose watch on the developmentof wear.

The pilot bit: Stop-lug forreamer - the reaming diameterdiminishes if wear to the stop-lugbecomes too great.

The reamer: Stop-lug - the rea-ming diameter diminishes if wearto the stop-lug becomes too great.

The guide device: Outsidediameter of the lower part -excessive wear causes poorguiding in the casing shoe. Thiscan result in breakage of the pilotbit thread or of the guide deviceshaft.

33


Build-up welding(hardfacing)

The service life of TUBEX XLcomponents can be extended byhardfacing the zones that havebeen most badly affected bywear, e.g.

Pilot bit: Stop-lug for reamer, hard-face when wear exceeds 3-4 mm.

Reamer: Stop-lug, hardfacewhen wear exceeds 3-4 mm.

In order to protect the buttons,hardfacing can also be applied tothe periphery of the reamer, ifnecessary.

Guide device: Restore thediameter of the lower part of theguide device when wear exceeds3-4 mm. Restore the appearanceof the upper part of the flushinggrooves. This will preventunnecessary wear to the front endof the DTH hammer.

Guide sleeve: Restore thediameter of the guide sleevewhen wear exceeds 3-4 mm.

Hardfacing can be carried out intwo ways:

Method 1: Pre-heat to max. 200°C. Apply one weld layer usingCastolin 2222, Castolin 6200 oran equivalent electrode of anothermake. Finish off with a layer ofCastolin 6080, or equivalent.

Method 2: Pre-heat to max. 200°C. Build up surface using Casto-

lin 6080, or an equivalent electro-de of another make.

N.B. Method 1 gives a betterresult, with less risk of crack

formation in the original material.

The above instructions also applyto TUBEX XL equipment fortophammers.

N.B. Normal product guarantees are not valid after hardfacing.

4/201

34


TUBEX XL Rock drill Casing, recom. size, mm Min. wall Max. drill Reaming Road - bankTYPE thickness bit diameter diameter bit diameter

mm mm A mm B mm C

90* A 30-15 115 102 5 90 123 125COP 32

115* A 34-15 142 128 5 115 152 155SD-4XL 4COP 42DHD 340ADH-4

140 A 43-15 171 157 5 140 187 190SD-5XL 5XL 5,5COP 42COP 52DHD 350RDH-5

165 B 53-15 196 183 5,5 165 212 215SD-6XL 6COP 62DHD 360DH-6SF-6SF-6L

190 B 53-15 222 205 6,3 190 237 240SD-6A 63-15SD-8COP 62DHD 360

215 A 63-15 257 241 6,3 215 278 275SD-8COP 62DHD 380

240 A 63-15 273 260 6,3 240 306 295SD-8DHD 380

280‡ SD-10 327 305 7,1 280 370 345

365 A 100-15 406 387 7,1 365 450 430SD-12

* Threaded casing tube also available‡ Not standard

Max. OD Min. ID

TUBEX XL PRODUCT RANGEFor DTH hammer with casing shoe

35


Rock drill Casing, recom. size, mm Min. wall Max. drill Reamingthickness, bit diameter, diameter,mm mm A mm B

76* TRP 600 89 78 4,5 76 96BBE 57

COP 1238

127* TRP 600BBE 57 142 128 5 127 162

COP 1238

Max. OD Min. IDTUBEX XL

TYPE

ø OD ø ID

4-2/204

B

ID

OD

A

B

A

ID

OD

TUBEX XL for horizontal drilling, with breakthrough

4/205 4/206

4/204

Casing tubes for DTH drilling Casing tubes for tophammer drilling

TUBEX XL PRODUCT RANGEFor Tophammers (no casing shoe)

36


4/202

SOME IMPORTANT POINTS ABOUT TUBEX XL DRILLING- embankment drilling, for

installing pipes and cablesunder roads and railways

- overburden drilling followed bydiamond drilling in the bedrock

- cuttings sampling- earth sampling- investigation of thickness of

overburden- ground water level investigation- underwater drilling

Applications - TUBEX XLfor DTH hammers

- well drilling (for water, draina-ge, investigation, heat-pumpinstallation, observation wells inrefuse dumps, monitoring wells)

- grout injection drilling- anchor installation drilling- pile installation (steel cores)- ground reinforcement (under-

pinning)- sheet piling (pile walls)- underwater drilling- road/rail embankment drilling- blasthole drilling- drilling for sampling purposes

The TUBEX XL method offersmany advantages over othermethods and is often the onlypractical way of drilling throughtroublesome overburden. Itshould be remembered, however,that success with TUBEX XLrequires attention to certaindetails. Some of the more impor-tant details are as follows:

1 Correct choice of casing tubes(regarding inside/outsidediameter and length).

2 Hardened threads - casing tubesintended for re-use should havehardened threads.

3 Correct welding (when unthrea-ded casing tubes are used).

4 Flushing: selection of suitableflushing medium for the type ofdrilling in question.

5 Correct drilling procedure.

The illustration above showsbasic drilling procedure.

A TUBEX XL is used to drillthrough the overburden, down

to the bedrock. The casing tubesare driven a short way into thebedrock. The TUBEX XLequipment is then pulled upthrough the inside of the casingtubes, and removed.

B Conventional drill steel equip-ment is fitted, and drillingcontinues in the bedrock (can betophammer, DTH hammer ordiamond-drilling equipment).

C Hole is completed. Drill stringis withdrawn, leaving casingtubes supporting the holethrough the overburden.

Depending on the purpose of thehole, the casing tubes can eitherbe left in the hole or pulled upand re-used, in which case theyshould have hardened threads.

Applications - TUBEX XLfor tophammers- overburden drilling followed by

blasthole drilling in the under-lying bedrock

- drilling for anchor installation- drilling for grout injection

37


pdf © 2004

Driltech Mission, LLC 1300 Heritage Pkwy Mansfield, TX 77603 USA Tel 1 817 453 2600 Fax 1 817 453 2389www.sandvik.mission.com

Documents

TUBEX XL DTH DRILLING TOOLSdrilling. It enables holes to be drilled successfully through all kinds of overburden, even that in which boulders of varying sizes are suspended. With the