WO2013170312A1

WO2013170312A1 - Injection and drive arrangement for rock bolting

Info

Publication number: WO2013170312A1
Application number: PCT/AU2013/000517
Authority: WO
Inventors: Peter Andrew Gray
Original assignee: Individual
Current assignee: Individual
Priority date: 2012-05-17
Filing date: 2013-05-17
Publication date: 2013-11-21
Anticipated expiration: 2014-11-17

Description

TITLE OF THE INVENTION

INJECTION AND DRIVE ARRANGEMENT FOR ROCK BOLTING BACKGROUND OF THE INVENTION

1. Field of the Invention

[0001] The present disclosure relates to relates to an injection and drive arrangement and method for drilling and rock bolting. The disclosure has particular application to drilling using drill rods and self-drilling rock bolts for mining and civil applications, but is not restricted thereto.

2. Description of Related Art

[0002] The mining and tunnelling industries increasingly use self-drilling rock bolts to support the roof and walls of roadways and tunnels. Typically self- drilling rock bolts are installed using cement grout to anchor these bolts in boreholes.

[0003] Some self-drilling rock bolts use chemical resin to anchor the bolts. The OneStep™ self-drilling rock bolt by Hilti Corporation uses a resin cartridge which is contained within the hollow bolt, and which is forced out of the bolt after drilling by high pressure water. However, the use of resin cartridges with self drilling rock bolts means that the volume of resin available to fill the borehole is strictly limited, and if the rock has any cracks or cavities in the borehole, then the self drilling rock bolt will not be fully encapsulated. In mines with highly stressed rock, much of the resin available will be used to fill cracks at the end of the borehole, leaving the trailing half of the bolt with little or no resin encapsulation.

[0004] Consequently, there is an advantage in using pumpable resin with self-drilling rock bolts such that the volume of resin is not limited, and the bolt can be pumped full of resin until it is fully encapsulated. However, pumping resin into a self- drilling rock bolt requires the use of two part chemical resins which will gel and harden once they are mixed together. [0005] WO 2010/031132 discloses an inj ector arrangement for rock bolting which maintains separate flow passages for the resin components until the resin enters the rock bolt. While this injector arrangement solves many problems, a need exists for a combined drive and injector arrangement.

SUMMARY OF THE INVENTION

[0006] In a first aspect, the disclosure aims to provide a new fluid injection and drive arrangement and method for a self-drilling rock bolt.

[0007] A further aspect of the disclosure aims to provide a drilling arrangement and method for percussive drilling of a borehole, optionally by means of a self-drilling rock bolt. *

[0008] In one form, the invention provides a drive arrangement for a self- drilling rock bolt comprising:

a non-rotary body having a first fluid inlet and a second fluid inlet;

a rotary drive shank supported by the body to allow rotation, the rotary drive shank having a first end, a second end and a rotational axis, the first end being adapted in use to be driven by a rotary drive and the second end being adapted in use to drive rotation of the self-drilling rock bolt;

the rotary drive shank further having an axial bore which is open at the second end of the rotary drive shank, a first fluid passageway connecting the first fluid inlet of the drive member body to the axial bore, and a second fluid passageway connecting the second fluid inlet of the drive member body to the axial bore;

a fluid divider insertable in the axial bore of the rotary drive shank, being structured to divide the axial bore into first and second chambers, the first chamber leading from the first fluid passageway of the rotary drive shank to the second end of the rotary drive shank, and the second chamber leading from the second fluid passageway of the rotary drive shank to the second end of the rotary drive shank; the arrangement being structured to provide separate injection pathways from the respective first and second fluid inlets to a fluid inlet of the self-drilling rock bolt. [0009] The first fluid inlet may comprise an inlet port for a first resin component of a two-part resin and optionally for a first flushing fluid connection, and the second fluid inlet may comprise an inlet port for a second resin component of the two-part resin and optionally a second flushing fluid connection.

[0010] In one example form, the drive arrangement may further comprise a third fluid inlet and a third fluid passageway connecting the third fluid inlet to the axial bore.

[0011] Optionally, the third fluid passageway communicates with the second chamber at a location spaced lengthways along the axial bore between the second fluid passageway and the second end of the axial bore, and the arrangement may include a one-way valve to inhibit flow of the third flow to the second fluid passageway.

[0012] A further form of the invention provides a fluid divider for insertion in a rotary drive shank of a drive arrangement for a self-drilling rock bolt, the rotary drive shank having a first end to engage a rotary drive, second end for rotating the rock bolt and an axial bore adapted to receive the fluid divider, and the drive arrangement having a first fluid passageway and a second fluid passageway for inlet of respective first and second fluids into the axial bore, the fluid divider comprising a tubular fluid divider adapted to divide the axial bore into a first inner chamber and a second outer chamber, an annular seal adapted to seal against the axial bore between the first fluid passageway and the second fluid passageway, and an aperture in the tubular fluid divider to provide communication of fluid from the first fluid passageway into the first chamber, the tubular fluid divider providing separate injection pathways from the first fluid passageway and the second fluid passageway to the second end of the rotary drive shank.

[0013] One further form of the invention provides a drive arrangement for rotary percussive drilling, comprising:

a drive socket adapted to receive a drilling member, the drive socket having a drive socket base; _. ^' "

the drive socket being attached to a rotary drive shank and the drive shank being adapted to receive rotary percussive energy from a rotary percussive drive and to impart that energy to the drive socket,

further including an insert member inserted in a base of the drive socket to space the drilling member from the drive socket base.

[0014] In example forms of the rotary percussive drive arrangement:

- the insert member may include a fluid passage for receiving one or more fluids injected via the drive shank and for directing the one or more fluids into a fluid passage of me drilling member;

- the passage of the insert member may be adapted to direct a flushing fluid to me drilling member during drilling; and or

the passage of the insert member may also be adapted to direct an encapsulation resin into the drilling member following drilling.

[0015] The invention further relates to methods of drilling and of installing rock bolts, and apparatus for drilling and for rock bolt installation, as described.

[0016] Further forms of the invention disclosure will be apparent from the following description and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Further preferred embodiments of the invention will now be described with reference to the accompanying drawings, in which:

[0018] Figure 1 is a perspective view of a first embodiment of a drive and injection arrangement, adapted for rotary drilling of a self-drilling rock bolt;

[0019] Figure 2 is a cross-sectional elevation of the arrangement of Fig. 1 ;

[0020] Figure 3 is a perspective view of a fluid divider tube of the arrangement of Fig. 1;

[0021] Figure 4 is a perspective view of a second embodiment of a drive and injection arrangement, adapted for rotary percussive drilling; [0022] ^' Figure 5 is a sectional plan view of the arrangement of Fig. 4;

[0023] Figure 6 is a schematic perspective of the drive shank of the arrangement of Figs. 4 to 5;

[0024] Figure 7 is a perspective view of a third example embodiment of a drive and injection arrangement, adapted for rotary drilling of a self-drilling rock bolt;

[0025] Figure 8 is a cross-sectional elevation of the arrangement of Fig. 7; and

[0026] Figure 9 is a perspective view of a fluid divider tube of the arrangement of Fig. 7.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0027] A first example embodiment of the drill drive and injection arrangement, described with reference to Figs. 1 to 3, is adapted for driving rotation of a rotary drill rod or self-drilling rock bolt, typically for drilling of 'soft' rock up to a compressive strength of about lOOMPa - based on unconfined compressive strength of rock as tested out for example by ASTM D7012-10; D2938; D2166-06; BS 1377-7 1990 - such as often encountered in coal mining.

[0028] Illustrated components of the first embodiment are given ' 100- series' reference numerals. Where possible, similar components of the second, rotary percussive, embodiment of Figs. 4 to 6 are referenced with equivalent '200-series' reference numerals, and similar components of the third embodiment of Figs. 7 to 9 are referenced with equivalent '300-series' reference numerals.

[0029] With reference to Figs. 1 to 3, the illustrated drill drive and injection assembly 100 is adapted for fixing to the drilling machinery (not shown) with which the assembly is used, for example attached to the drill frame, so that the assembly 100 moves up and down with the drilling machinery in use. The support arm 102 is fixed to the drilling machine (not shown) and to the housing 104, such that as the drive shank 106 is rotated by the drilling machine, the housing 104 does not rotate. [0030] The major components of the assembly comprise a drive assembly body 104, a drive shank 106 rotatably mounted through the drive assembly body 104, and drive body end cap 108 and a drive socket 110, commonly known in the mining industry as a drive dolly, for driving rotation of the rock bolt (not shown in Figs. 1 to 3).

[0031] The drive assembly body 104 is a generally cylindrical body having central bore 111, and a plurality of fluid inlet ports 112a, 112b forming passages leading from the drive body exterior to its interior. The inlet ports 112a, 112b may be screw-threaded or have other connection formations for connection to injection fluid sources (typically hoses which are not shown). Ports 112a and 112b are longitudinally spaced along the length of the drive body, to communicate with the body interior at different positions along the drive body interior. In the example embodiment of Figs. 1 to 3 there are two pairs of inlet ports, 112a and 112a', and 112b and 112b'.

[0032] It will be seen from Fig. 2, the pair of inlet ports 112a/l 12a' communicate with a first annular fluid channel 114a, 114b inside the bore 111 of the drive assembly body 104, and inlet ports 112b/l 12b' communicate with a second annular fluid channel 114b.

[0033] Journalled within the bore 111 of the drive assembly body 104 and the end cap 108 by bearings 1 5 is a drive shank 106 having a drive formation 116 at a first end adapted for co-operating with the drilling machinery (not shown) so as to rotate the drive shank 106 about its central rotational axis 107 and, with it, the drive socket 110 connected to the opposite, second end of the drive shank 106. The drive socket has a socket formation 160 adapted to connect to a drive nut on the rock bolt (the rock bolt and its drive nut not being shown in this embodiment) to rotate the drive shank.

[0034] Ring seals 118 of Teflon (PTFE), Viton™ (fluoroelastomer) or similar are located within the bore 111 of the drive body 104 to seal against the outer surface of the drive shank at longitudinally spaced apart locations, including seals located between the annular fluid channels 114a and 114b. [0035] The drive shank has an axial bore 120 along its longitudinal axis, the bore being closed at its first end furthest from the rock bolt, and open at the second, drive socket end.

[0036] The drive shank has radial fluid passages 122a, 122b

communicating between the respective annular channels 114a, 114b of the drive assembly body 104 and the axial bore 120 of the drive shank.

[0037] Inserted into the axial bore 120 of the drive shank from its open end is a flow divider tube 124 (shown also in Fig. 3) with annular spacer seals 126, for example annular skirt valves, on its outer surface, dividing the axial bore 120 into an inner fluid chamber 128 inside the tube, and an annular fluid chamber 130 formed between the divider tube 124 and the inner surface of the cylindrical bore 120. An aperture 132 in the flow divider tube 124 allows fluid communication from the first fluid port 122a via the respective annular fluid channel 114a and aperture 132 to the inner fluid chamber, forming a first passageway to the second end of the drive shank into the drive socket

[0038] The second fluid inlet port 112b and second annular channel 122b communicate with the annular fluid chamber 130, to form a second passageway also leading to the second end of the drive shank into the drive socket.

[0039] The fluid passage system and the fluid divider tube thus keep the fluids introduced through the fluid inlet port pair 112a/l 12a' separated from fluids introduced through and inlet port pair 112b/l 12b' until the fluids exit the drive shank, whereupon they may pass through a valving and passageway member in the trailing end of the rock bolt, such as described in WO2010/031132 (incorporated herein by reference) in the drive socket before entering the rock bolt passage.

[0040] The drive dolly with fluid passage system and fluid divider mates with seals in the valving and passageway member, which has separate passageways and one-way valves to maintain the separation of the fluids - for example two components of a resin - until they enter the rock bolt. In this way, the two parts of the resin will not come into contact, and thus will not cure and harden, within the drive dolly and injection passageways.

[0041] The illustrated drive and injection arrangement is adapted for drilling and securing of a self-drilling rock bolt by means of a pumpable two-part resin, for example a two-component silicate resin such as Carbothix™ manufactured by Orica/Minova International, or a two-part polyester resin.

[0042] In use, the support arm 102 of the assembly is attached to the drill motor of a drilling machine, and fluid tubes connected to the inlet ports. The rotary drive of the drilling machine is connected to the drive formation 116 of the drive shank protruding from the back of the drive assembly.

[0043] Water for drilling and/or flushing, and a water soluble part A of the two-part resin are connected to respective ones of inlet ports 112a and 112a'.

[0044] Oil or water, and part B of the two-part resin are connected to respective ones of inlet ports 112b and 112b' .

[0045] The relative dimensions of the cylindrical bore 120 in the drive shank and the divider tube 124 may be selected to provide relative cross-sectional areas of the first (inner, 128) and second (annular, 130) flow chambers thus formed to suit the proportions of the resin components to be used. For example, for a resin mix requiring a 1 :2 ratio of Part A to Part B of the resin, a divider tube outside diameter of 9.5mm (internal diameter 8mm) in a shank bore diameter of 16mm will provide approximately the correct cross-sections. The pump pressures of the two parts of the resin may also differ to adjust the ratio of the two components. For example, Part A of the resin may be pumped at 350-500 psi, and Part B at 550-600 psi.

[0046] Materials and construction of the drive and injection assembly components should be suitably robust to withstand the rigours of the mining environment in which they will be used. For example, the drive body, drive shank and the drive socket may be formed from cast or machined metals, whilst the fluid divider tube is preferably formed of injection moulded plastics material of suitable properties and chemical resistance, for example low density polyethylene because of its cheap cost and chemical resistance.

[0047] The drive socket 110 may be screw threaded onto the shank by suitably robust screw thread, for example a R38 rope threads 161, 162 with locking screw, or other suitable arrangement such as a spline arrangement.

[0048] By providing the fluid divider tube within the bore of the drive shank, the flow passages to the rock bolt are formed within the drive shank and remain separate during rotation of the drive shank, without need for the complex machining operations which would be needed to form these passages in the drive shank itself.

[0049] Furthermore, the fluid divider tube can be removed from the drive shank in the event of damage or clogging, and a new one inserted.

[0050] The seals 126 between the fluid divider tube 124 and the bore 120 of the drive shank 106 may be integrally moulded as part of the divider tube, as shown, or may be separately formed. In that case, the fluid divider tube may have formation such as annular grooves on its outer surface to locate annular seals such as O-rings.

[0051] The surface of the drive shank may be flash chromed by known processes, at least in the vicinity of the seals 118 between the drive shank and the drive assembly body, to provide a hard and smooth surface which optimises sealing between the drive shank and the drive assembly body and provides improved seal life at the relatively high rotational speeds, for example up to about 500 rpm, used.

[0052] In use, a self-drilling rock bolt with drive nut is inserted into the drive socket 110, and the drilling machine moved up until the drilling tip of the self- drilling rock bolt engages the mine surface to be drilled.

[0053] The rotary drive of the drive machine is rotated in a first direction, typically counterclockwise, causing the drive nut on the self-drilling rock bolt to rotate the self-drilling rock bolt to drill into the mine surface. [0054] Water is injected through port 112a or 112a', passing through annular fluid channel 114a, aperture 132 and the inner fluid chamber of the fluid divider tube to the drive socket, and into the self-drilling rock bolt which has a passage extending lengthwise to the drilling tip for the water to flush away material as drilling progresses.

[0055] When drilling is completed, the components of the two-part resin mix may be introduced in the desired proportions to the self-drilling rock bolt via respective inlet ports 112a or 112a', and 112b or 112b', the components remaining separated while passing through the passageway arrangement as described above to enter the self-drilling rock bolt, only at which point do the two resin components mix. If desired, the fluid passage of the self-drilling rock bolt may contain a static mixer, for example of a type known per se in the prior art, to assist mixing of the resin components.

[0056] The resin passes along the length of the rock bolt and exits the end of the rock bolt into the borehole, encapsulating the rock bolt within the borehole. Once the resin is set and the self-drilling rock bolt is secured in the hole, the rotation direction of the rotary drive is reversed, to cause the nut to tighten and provide axial tension to the rock bolt.

[0057] In this way, the drilling and injection steps of the rock bolt installation may be conducted without need to remove the drive machine from the rock bolt to attach separate a separate resin injection unit to the rock bolt for resin injection.

[0058] Prior to installation of the next self-drilling rock bolt using the drive assembly, the respective passageways of the drive assembly may be flushed clean by introducing water into inlet port 112a or 112a', and either water or oil into inlet port 112b or 112b'.

[0059] Figs. 4 to 6 illustrate a second example embodiment of the invention adapted for rotary percussive drilling of 'hard rock', for example in mining of rock with a hardness of about 100-300MPa. The components of the drive and injection assembly 200 are generally similar to those of Figs 1 to 3, with similar components indicated by equivalent '200-series' reference numerals.

[0060] The drive and injection assembly 200 comprises a drive assembly body 204, a drive shank 206 with drive formation 216 at one end and a drive socket/dolly 210 at its other end, in similar general arrangement to the previously described embodiment.

[0061] The drive assembly body 204 is attached to the drilling machinery (not shown), also as previously described.

[0062] The main differences from the first embodiment relate to construction of the drive shank 206 and drive socket 210, which are adapted to transmit percussive energy as well as rotary drive of approximately 350-400 rpm to the rock bolt during drilling.

[0063] The drive formation 216 of drive shank 206 is specifically adapted to co-operate with a rotary percussive drive (not shown), which may be of any suitable type depending on the type of drilling machinery being used. The illustrated form includes an internal rope thread 260 for connection to the rotary percussive drive.

[0064] The drive socket arrangement 210 includes a drive thrust insert 234 which provides contact with the nut 236 at the end of the self-drilling rock bolt 238 to transmit the percussive energy and separate the nut 234 and the bolt end from the base of the drive socket, to protect the drive socket surface from damage from the end of the rock bolt.

[0065] The drive shank 206, socket 210 and thrust insert 234 may be made of any suitable material capable of withstanding both the rotary and percussive loads on these components. Hardened steel, for example of hardness of 50 or more on the Rockwell C scale, may be suitable for these components.

[0066] The fluid divider tube may have similar construction and sealing arrangements to that described previously with reference to Figs. 1 to 3. [0067] The fluid injection passages formed within the drive assembly body

202, drive shank 206 and fluid divider tube 224 are similar to those described for the

first embodiment, and operate in a similar way.

[0068] As can be seen in Fig. 5, the fluid divider tube 224 extends past the

end of the drive shank and into the drive socket portion, ending within the thrust insert

234 which provides the final part of the injection passage leading to the rock bolt.

[0069] The illustrated arrangement of Figs. 4 to 6 allows the connection of

the drive socket to the rock bolt to be a simple insertion of the rock bolt in the socket,

retained by the thrust applied by the drilling machinery. This differs from the

conventional arrangement in percussive drilling where the drive socket is required to

be threaded onto the rope thread of the rock bolt, which is time consuming and prone

to difficulty if the thread is damaged.

[0070] Figs. 7 to 9 illustrate a third example embodiment of the invention

adapted for rotary drilling of 'soft' rock, similar to that described above in relation to

Figs. 1 to 3. The components of the drive and injection assembly 300 are generally

similar to those of Figs 1 to 3, with similar components indicated by equivalent '300- series' reference numerals.

[0071] The assembly includes a non-rotary body 304 with rotary shank 306

generally similar to Fig. V, including drive formation 316 and drive socket 310

operating analogously to their equivalents described above with reference to Fig. 1.

[0072] Drive shank 306 is supported for rotation within the bore of the

drive assembly body 304 by thrust bearing 315, seals 318 and support rings 313a and ^' 313b, with washer 317 acting to reduce friction with the end face of the body 304.

Attachment of the shank 306 to the body 304 is held in place by lock nut 309.

[0073] At its first (rear) end the shank has a drive formation 316 adapted

for co-operating with the drilling machinery as previously described and, rotating with

it, the drive socket 310 with socket formation 360 connected to the opposite, second

end of the drive shank 306. [0074] The drive shank has an axial bore 320 along its longitudinal axis, the bore being closed at its first (rearmost) end furthest from the rock bolt, and open at the second, drive socket end.

[0075] In the example embodiment of Figs. 7 to 9, three sets of fluid inlet ports 312a, 312b, 312c are longitudinally spaced along the length of the drive body, to communicate with the axial bore 320 at different positions along the drive body interior.

[0076] It will be seen from Fig. 8, each set of inlet ports 312a/312a', 312b/312b' and 312c communicates with a respective annular fluid channel 314a, 314b, 314c inside the bore 320 of the drive assembly body 304, forming inlets for the respective fluids at spaced locations along the length of the axial bore.

[0077] The drive shank has radial fluid passages 322a, 322b, 322c communicating between the respective annular channels 314a, 314b, 314c of the drive assembly body 304 and the axial bore 311 of the drive shank.

[0078] The flow divider tube 324 of this example, shown separately in Fig. 9, has annular spacer seals, for example annular skirt valves 326 and 327 and/or grooves 334 to accommodate o-rings 319 (Fig. 8), on its outer surface, dividing the space between axial bore 311 and the tube lengthways into three sections.

[0079] The seals, together with lugs 330, also help position the flow divider tube 324 coaxially within bore 311 of the drive shank 304.

[0080] The rearmost section between rearmost skirt valve 327 and the o- ring seals 319 communicates with the fluid inlets 312a, 312a' for the first fluid. The aperture 332 in the flow divider tube 324 allows fluid communication from the first fluid port 322a via the respective annular fluid channel 314a and aperture 332 to the inner fluid chamber, forming a first chamber for fluid to pass to the second end of the drive shank into the drive socket

[0081] The section between the o-rings 319 and front skirt valve 326 communicates with the fluid inlets 312b, 312b' for the second fluid. Skirt valve 326 < acts as a one-way valve, opening under pressure of the second fluid to allow the fluid to pass along the annular chamber between the tubular flow divider and bore 311 to exit the open end of the bore 311.

[0082] The section forward of skirt valve 326 communicates with the third fluid inlet 312 for the third fluid. Because skirt valve 326 acts as a one-way valve, the third fluid is prevented from travelling back along towards the second fluid passageways 322b and instead the third fluid may exit only at the open end of bore 311 at the second end of the drive shank, inside the drive socket.

[0083] In use, the first fluid inlets 312a may be connected for example to a source of an oil soluble 'Part B' of a two-part resin, second fluid inlets 312b to water soluble 'Part A' of the resin, and third inlet 312c to a source of drilling water.

[0084] Part A and Part B of the resin are thus kept separate until the fluids exit the drive shank to enter the rock bolt, as described for previous embodiments, while drill flushing water introduced through inlet 312c is prevented by skirt valve 326 from flowing back along the outer chamber to the Part A and Part B fluid inlets 312a and 312b.

[0085] In this specification, the word "comprising" is to be understood in its "open" sense, that is, in the sense of "including", and thus not limited to its "closed" sense, that is the sense of "consisting only of. A corresponding meaning is to be attributed to the corresponding words "comprise, comprised and comprises where they appear.

[0086] While particular embodiments of this invention have been described, it will be evident to those skilled in the art that the present invention may be embodied in other specific forms without departing from the essential

characteristics thereof. The present embodiments and examples are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. It will further be understood that any reference herein to known prior art does not, unless the contrary indication appears, constitute an admission that such prior art is commonly known by those skilled in the art to which the invention relates.

[0087] For example, while particular embodiments of the invention are described with reference to installation of self-drilling rock bolts in mining or other geotechnical applications, it will be appreciated that the invention will have application to other uses, such as to rotary and rotary percussive drilling applications more generally.

Claims

1. A drive arrangement for a self-drilling rock bolt comprising:

a non-rotary body having a first fluid inlet and a second fluid inlet;

a fluid divider insertable in the axial bore of the rotary drive shank, being structured to divide the axial bore into first and second chambers, the first chamber leading from the first fluid passageway of the rotary drive shank to the second end of the rotary drive shank, and the second chamber leading from the second fluid passageway of the rotary drive shank to the second end of the rotary drive shank; the arrangement being structured to provide separate injection pathways from the respective first and second fluid inlets to a fluid inlet of the self-drilling rock bolt.

2. A drive arrangement according to claim 1 , wherein the fluid divider is tubular, and divides the axial bore into inner chamber being said first chamber and an outer chamber being said second chamber.

3. A drive arrangement according to claim 2 wherein the inner chamber is formed within the tubular fluid divider, and the outer chamber is formed between the tubular divider and a wall of the axial bore.

4. A drive arrangement according to claim 2, further including an annular seal between the tubular fluid divider and the axial bore, the seal being located between the first fluid passageway and the second fluid passageway to separate said injection pathways.

5. A drive arrangement according to claim 4, wherein the seal comprises one Or more seal formations formed on the tubular fluid divider.

6. A drive arrangement according to claim 4, wherein the first fluid passageway and the second fluid passageway are spaced lengthways along the axial bore, and wherein the seal is a ring seal located between the first fluid passageway and the second fluid passageway.

7. A drive arrangement according to claim 1 , wherein the first fluid inlet comprises an inlet port for a first resin component of a two-part resin , and the second fluid inlet comprises an inlet port for a second resin component of the two-part resin.

8. A drive arrangement according to claim 1 , further comprising a third fluid inlet and a third fluid passageway connecting the third fluid inlet to the axial bore.

9. A drive arrangement according to claim 8 wherein the third fluid passageway communicates with the second chamber at a location spaced lengthways along the axial bore between the second fluid passageway and the second end of the axial bore.

10. A drive arrangement according to claim 9 wherein the second chamber includes a one-way valve between the second fluid passageway and the third fluid passageway.

11. A drive arrangement according to claim 10, wherein the one-way valve is configured to allow fluid from the second fluid passageway to flow past the third fluid passageway to the second end of the axial bore, but to inhibit backflow from the third fluid passageway to the second fluid passageway.

12. A drive arrangement according to claim 11, wherein the fluid divider is tubular, the second chamber is an outer chamber formed between the fluid divider and the axial bore, and the one-way valve comprises an annular valve formation between the tubular fluid divider and the axial bore.

13. A drive arrangement according to claim 12, wherein the annular valve formation is a skirt valve formed on an outer surface of the fluid divider.

14. A fluid divider for insertion in a rotary drive shank of a drive arrangement for a self-drilling rock bolt, the rotary drive shank having a first end to engage a rotary drive, a second end for rotating the rock bolt and an axial bore adapted to receive the fluid divider, and the drive arrangement having a first fluid passageway and a second fluid passageway for inlet of respective first and second fluids into the axial bore, the fluid divider comprising a tubular fluid divider adapted to divide the axial bore into a first inner chamber and a second outer chamber, an annular seal adapted to seal against the axial bore between the first fluid passageway and the second fluid passageway, and an aperture in the tubular fluid divider to provide communication of fluid from the first fluid passageway into the first chamber, the tubular fluid divider providing separate injection pathways from the first fluid passageway and the second fluid passageway to the second end of the rotary drive shank.