AU2019264566B2

AU2019264566B2 - Cable bolt

Info

Publication number: AU2019264566B2
Application number: AU2019264566A
Authority: AU
Inventors: Timothy Joseph Gaudry; Matthew Raffaele Holden
Original assignee: Fci Holdings Delaware LLC
Current assignee: Fci Holdings Delaware LLC
Priority date: 2018-11-12
Filing date: 2019-11-12
Publication date: 2024-11-14
Anticipated expiration: 2039-11-12
Also published as: AU2019264566A1

Abstract

Disclosed is a cable bolt comprising a flexible cable formed from a plurality of wound co-extending strands, and at least one the strands is a hollow strand. At least one reinforcing member disposed in the hollow strand. The at least one 5 reinforcing member increases loading capacity of the cable bolt. [Fig. 2] 11803252_1 (GHMatters) P109836.AU.1 Cr r4 r NL ~ LL r4 m

Description

Cr r4 r

NL

~ LL

r4 m

CABLE BOLT TECHNICAL FIELD

The present disclosure is directed to a cable bolt assembly that is suitable for use in mining and tunnelling to provide rock and wall support. The cable bolt assembly is suitable for use in hard rock applications as well as in softer strata, such as that often found in coal mines. Thus, the term "rock" as used in the specification is to be given a broad meaning to cover all such applications.

BACKGROUND ART

Roof and wall support is vital in mining and tunnelling operations. Mine and tunnel walls and roofs consist of rock strata, which must be reinforced to prevent the possibility of collapse. Rock bolts, such as rigid shaft rock bolts and flexible cable bolts are widely used for consolidating the rock strata.

Known methods for reinforcing rock faces include the use of tensionable cable bolts that are configured to allow post tensioning grouting of the cable into a rock bore hole. These cable bolts are usually made from a plurality of steel filaments wound together to form a tendon. The cable bolt may be fully encapsulated with grout, which allows load transference of any ground movements to the cable, creating a stiffer support system. However, these types of grouted cable bolts often fail (as shown in Figs. la and 1b) through excessive loading. For example, excessive shear loading is caused by transverse movement along discontinuities in the rock.

It is to be understood that, if any prior art is referred to herein, such reference does not constitute an admission that the prior art forms a part of the common general knowledge in the art, in Australia or any other country.

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21206315_1(GHMtters) P109836.AU.1

SUMMARY

According to a first aspect, disclosed is a cable bolt extending along an axis between opposite ends, the cable bolt comprising:

a flexible cable formed from a plurality of wound co-extending strands, and at least one the strands is a hollow strand;

a settleable material; and

at least one reinforcing member embedded in the settable material and disposed in the hollow strand,

wherein the at least one reinforcing member increases loading capacity of the cable.

In some embodiments, the at least one reinforcing member increases at least one of the tensile and shear loading capacity of the cable. In some embodiments, the at least one reinforcing member is primarily designed to increase the shear capacity of the cable. The at least one reinforcing member may increase the shear capacity of the cable through a 'doweling' mechanism and is dependent on the cross-sectional area and material properties of the at least one reinforcing element.

In some embodiments, the at least one reinforcing member is in the form of a longitudinal element.

In some embodiments, the plurality of strands includes a centre strand and the centre strand is the hollow strand.

In some embodiments, the cable bolt further comprises a settable material, wherein the at least one hollow strand is configured to receive the settable material and the at least one reinforcing member. In some embodiments, at least one reinforcing member is embedded within the settable material when it is hardened.

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21206315_1 (GHMatters) P109836.AU.1

In some embodiments, the hollow strand includes profiling. It is understood that profiling may include corrugations, ribs, texturing or any type of uneven surface. In some forms, the profiling creates an interlocking relationship between the cable bolt components and the settable material to prevent slippage of the cable bolt. The profiling may extend part way along the length of the hollow strand, and may be spaced apart by a smooth section of the hollow strand. Ridges and grooves formed by the profiling may be of equal dimension or may be of varied dimension.

In some forms, the profiling is in the form of corrugations of the hollow strand. The corrugations may include ridges and grooves that increase the hollow strand's rigidity and strength. The corrugations may extend along the hollow strand and be axial or helical. The corrugations may create a mechanical interlocking relationship between the cable bolt components and the settable material. Advantageously, this improves load transferences between the outer filaments and the at least one reinforcing member. This contributes to increasing the tensile and shear strength of the cable bolt.

In one form, the settable material bonds to both the hollow strand and the at least on reinforcing member to allow load transference between the hollow strand and the at least one reinforcing element. In this way the at least one reinforcing element can increase the tensile capacity of the cable bolt.

In one form, the settable material is cementitious. In another form, the settable material is a resin, such as polyester resin or a urea silicate resin.

In another form, the at least one reinforcing member engages with the hollow strand through a mechanical interaction to allow load transference between the two so as to improve the tensile capacity of the cable bolt. For example, the mechanical interaction may be through keying of the components such as both elements including surface profiling which interfit. In one form, the two components may be threaded engagement. In another form, the at least one

3

21206315_1 (GHMatters) P109836.AU.1 reinforcing element may be arranged to radially expand and the two components are connected through frictional engagement or by virtue of an interference fit.

In some embodiments, the length of the at least one reinforcing member is less than the length of the cable.

In some embodiments, the length of the at least one reinforcing member extends the length of the cable corresponding to the area of the rock strata vulnerable to shearing.

In some embodiments, the at least one reinforcing member is relatively inflexible compared to the cable.

In some embodiments, the at least one reinforcing member has a diameter less than an internal diameter of the hollow strand. A snug fit between the at least one reinforcing member and the hollow strand is desirable to assist in frictionally retaining the at least one reinforcing member in position in the hollow strand.

In some embodiments, the at least one reinforcing member may be formed from a polymeric material, such as fibre reinforced polymer, or steel. In one form, the at least one reinforcing member is in the form of a reinforcing bar, and/or one or more cable strand (e.g., a PC strand). The at least one reinforcing member may be formed of a relatively rigid, inflexible, or flexible material depending on the requirements of the mine site and/or the user.

In some form, the at least one reinforcing member has a lower ductility than at least one of the strands of the cable bolt. In this way the addition of the at least one reinforcing member may aid the cable bolt to better accommodate dynamic loading environments

In some embodiments, the cable bolt has a distal end adapted for anchoring to rock strata, and a proximal end adapted for grouting. In some embodiments, the cable bolt further comprises an adaptor fitted to the proximal end of the cable for

4

21206315_1 (GHMatters) P109836.AU.1 facilitating the installation of the settable material, wherein the adaptor retains the at least one reinforcing member in relation to the cable bolt.

According to a second aspect, disclosed is a cable bolt assembly according to the first aspect further comprising a tensioning assembly mounted on an end of the cable, the tensioning assembly arranged in use to tension the cable. In some embodiments, the tensioning assembly comprises an end fitting being mounted to the proximal end of the cable. In some embodiments, the end fitting comprises a clamping device for clamping to the proximal end of the cable. In some embodiments, the tension assembly further comprises a bearer plate which is mounted to the cable between the end fitting and the first distal end of the cable. Tensioning the cable bolt compresses the rock strata that is in the vicinity of the cable bolt to bind the layers of rock strata to build a 'beam' that is more resistant to strata deformation. The at least one reinforcing member provides additional reinforcement thus further increasing the loading capacity of the cable bolt.

According to a third aspect, disclosed is a method of forming a cable bolt extending along an axis between opposing ends, the method comprising:

forming a length of flexible cable comprising a plurality of wound co extending strands wherein at least one of the strands is a hollow strand;

providing at least one reinforcing member for insertion in the at least one hollow strand for resisting loading;

providing a settable material, wherein the at least one reinforcing member is embedded in the settable material and disposed within the hollow strand.

In some embodiments, the method further comprises extending the hollow strand centrally between the other of the plurality of wound strands. In some embodiments, the method further comprises mounting a tensioning assembly to a proximal end of the cable. In some embodiments, the tensioning assembly includes an end fitting. In some embodiments, the end fitting includes a clamping

5

21206315_1 (GHMatters) P109836.AU.1 device. In some embodiments, the tensioning assembly includes a bearer plate which is mounted to the cable between the end fitting and a distal end of the cable.

According to a fourth aspect, disclosed is a method of installing the cable bolt comprising: installing a cable bolt in a bore in rock substrate, the cable formed from a plurality of wound co-extending strands, and at least one the strands is a hollow strand; disposing a settable material into the hollow strand of the cable, and inserting at least one reinforcing member into the settable material in the hollow strand. In some embodiments, the method further comprises tensioning the cable bolt using the tensioning assembly. In some embodiments, the method further comprises allowing the settable material to harden to retain the at least one reinforcing member. In some embodiments, the method further comprises fitting a grout adaptor to the proximal end of the cable to assisting to retain the at least one reinforcing member in the hollow strand.

In some embodiments, inserting the at least one reinforcing member is manually inserted. In some embodiments, inserting the at least one reinforcing member is mechanically inserted. In some embodiments, the hollow strand includes profiling.

It is understood that the cable bolt may include one or all of the features according to the first or second aspect.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will now be described by way of example only, with reference to the accompanying drawings in which

Figs. la andlb are a prior art cable bolt including a hollow cable being subjected to horizontal shearing along discontinuity in strata, Fig. 1 is a side view of the prior art cable bolt and Fig. lb is a cross-sectional view taken along a line extending longitudinally through the centre of the prior art cable bolt;

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21206315_1 (GHMatters) P109836.AU.1

Fig. 2 is a cross-sectional view taken along a line extending longitudinally through an embodiment of a cable bolt including at least one reinforcing member according to the present disclosure;

Fig. 3 is a cross-sectional view taken along a line extending radially of an embodiment of the cable bolt of Fig. 2;

Fig. 4a is a cross-sectional view taken along a line extending longitudinally of an embodiment of a cable bolt including a hollow strand and at least one reinforcing member;

Fig. 4b is a cross-sectional view taken along a line extending longitudinally of an embodiment of the cable bolt of Fig. 4a and the at least one reinforcing member is being inserted into the hollow strand;

Fig. 4c is a cross-sectional view taken along a line extending longitudinally of an embodiment of the cable bolt of Fig. 4b and the at least one reinforcing member is inserted into the hollow strand;

Fig. 5 is a perspective view with a cross-sectional cut-out of a further embodiment of a cable bolt and a further embodiment of a hollow strand; and

Fig. 6 is a close-up side view of the cross-sectional cut-out of Fig. 5.

DETAILED DESCRIPTION

In the following detailed description, reference is made to accompanying drawings which form a part of the detailed description. The illustrative embodiments described in the detailed description, depicted in the drawings and defined in the claims, are not intended to be limiting. Other embodiments may be utilised and other changes may be made without departing from the spirit or scope of the subject matter presented. It will be readily understood that the aspects of the present disclosure, as generally described herein and illustrated in the drawings can be arranged, substituted, combined, separated and designed in a

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21206315_1 (GHMatters) P109836.AU.1 wide variety of different configurations, all of which are contemplated in this disclosure.

A prior art cable bolt 10 is shown in Figs. la and b. The cable bolt extends between a proximal end 12 and a distal end 14 longitudinally along an axis. The prior art cable bolt includes flexible high-tensile wires 16 wound about a central hollow tube 18 located axially within the cable. The hollow tube 18 is adapted for cement grouting 20 although as would be understood, it may be designed to receive other settable materials such as resin. For example, in use, the distal end 14 is first point anchored, mechanically or with resin, and pre-tensioned before the grout 20 is introduced into the hollow tube 18. The cable bolt 10 is tensioned which results in compression of rock strata 22 surrounding the bore 24. The grout is pumped through the hollow tube 18 from the proximal end 12 to the distal end 14 and from the distal end 14 down an outer annulus between the exterior of the cable bolt 10 and the rock strata 22. The grout 20 is allowed to harden to bond the cable bolt 10 in the rock strata 22. The grout 20 is intended to fully encapsulate as it allows load transference of any rock strata movements to the cable bolt 10.

Typically, the prior art cable 10 bolt fails as a result of excessive loading. For example, the prior art cable bolt 10 shown in Figs. la and lb illustrates failure as a result of excessive shear loading. Excessive shear loading occurs when there is movement along discontinuities 30 in the rock strata 22 transverse to direction of the tension in the cable and the compression in the rock. The prior art cable bolt 10 is crushed at the area of discontinuity in the rock strata 22. This decreases the shear capacity of the cable bolt 10 and decreases the integrity of the cable bolt 10, which ultimately impacts the quality of rock strata 22 support and reinforcement in the mines.

Now referring to Figures 2 to 4c, illustrated is an embodiment of a cable bolt 100 as disclosed herein. The cable bolt 100 extends along an axis between a proximal end 112 and a distal end 114. The cable 100 is formed from a plurality of wound coextending flexible strands 116. At least one of the strands is a hollow strand

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21206315_1 (GHMatters) P109836.AU.1

118, which, in the illustrated embodiment, extends axially through the centre of the cable bolt 100. The distal end 114 of the cable bolt 100 is configured for point anchoring, either mechanical or resin, and the proximal end 112 is configured for tensioning and for introducing settable material 120 into the cable bolt 100 and bore 124.

As illustrated in Fig. 3, the plurality of strands comprises ten outer steel filaments 116a spiral wound about a central hollow filament 118, located axially within the cable 100. In alternative embodiments, more or fewer outer steel filaments 116a may be used, in which case their relative diameter with respect to the hollow strand 118 would be adjusted accordingly such that they are close fitting about the hollow strand 118. The strands 116, 118 are flexible to allow coiling of the cable. The flexibility of the cable also allows the cable bolt installed in mines with low roof heights while having a relatively long length (compared to other types of rock bolts such as rigid bolts) to allow the cable bolt to extend into the rock strata to provide stable anchorage.

At least one reinforcing member 126 is disposed in the hollow strand 118 which increases the loading capacity of the cable bolt 100. In the illustrated embodiment, the at least one reinforcing member 126 is in the form of one reinforcing member 126, but in alternative arrangements, there may be more than one reinforcing member disposed in the hollow strand and abutting end to end or in side by side relation. The reinforcing member 126 increases the cable bolt's 100 tensile loading capacity and the cable bolt's 100 shear loading capacity. The reinforcing member 126 is configured to increase the shear loading capacity of the cable bolt 100 through a 'doweling' mechanism. For example, as the cable is subjected to shearing (see Fig. 2), the reinforcing element 126 is pinned to interior walls of the hollow strand 118 on either side of the shear plane 130. This allows the reinforcing member 126 to resist shearing strain and contribute to the overall shear capacity of the cable bolt 100.

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21206315_1(GHMtters) P109836.AU.1

The reinforcing member 126 may also increase the tensile capacity of the cable bolt 100. The reinforcing member 126 may be inserted into unhardened settable material in the hollow strand 118. Once hardened, the settable material 120 may retain the reinforcing member 126 in position in the hollow strand with the bond formed by the settable material 120 between the hollow strand 118 and reinforcing member 126 allowing load transference to improve the cable bolt's 100 ability to accommodate tensile loading. This will be discussed in more detail below in relation to Figs. 4a to 4c.

In the illustrated embodiment, the reinforcing member 126 is in the form of a longitudinal element. The reinforcing member 126 has a diameter smaller than the inner diameter of the hollow strand 118 (as shown in Fig. 3). Also, the reinforcing member 129 may have a length less than the length of the cable bolt 100 extending between the proximal and distal ends 112, 114. The length of the cable bolt may extend at least the length of the zone in the rock strata susceptible to shearing. The zone susceptible to shearing can be determined on a site by site basis and will vary between sites. As a result, the reinforcing member may be positioned at a different distance between the proximal and distal ends of the cable bolt 112, 114 depending on the site, and on the position of the cable bolt 100 at the site to be aligned with the area or zone susceptible of shearing in relation to the specific cable bolt.

The reinforcing element 126 may be in any suitable form. For example, the reinforcing element shown in Fig. 3 is a seven-strand prestressed concrete steel strand ('PC strand'). Like the cable bolt itself, the PC strand reinforcing member may be formed from any number of wound strands. In alternative embodiments, more or fewer outer steel filaments may be used for the reinforcing member, in which case their relative diameter with respect to the interior diameter of the hollow strand 118 of the cable bolt 100 would be adjusted accordingly such that the diameter of the reinforcing member 126 is close fitting in relation to the internal diameter of the hollow strand 118.

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21206315_1 (GHMatters) P109836.AU.1

In further alternative embodiments, different grades of steel may be used for the strands which will impact the strength, ductility etc of the reinforcing member and therefore improve the response of the cable bolt under dynamic loading. In further alternative embodiments, the reinforcing member may be in the form of a fibre reinforced polymer, a polymer, or reinforcing bar. In further alternative embodiments, the reinforcing member may be smooth, scored, coated, or textured. In further alternative embodiments, the reinforcing member may be rigid, inflexible, flexible, or relatively rigid, inflexible or flexible relative to the cable bolt.

Now referring to Figs 4a to 4c which illustrate a cable bolt assembly including the cable bolt 100 discussed above, a method of forming the cable bolt 100 and a method of installing the cable bolt assembly in a bore in the rock strata. A tensioning assembly 138 is mountable to the proximal end 112 of the cable. The tensioning assembly comprises a clamping device 132 in the form of a barrel and wedge which is clamped to the proximal end 112 using known methods. Axial movement of the barrel upon the wedge causes the wedge to grip more tightly upon the proximal end 112 of the cable 100. The tensioning assembly also includes an abutting device 134 in the form of a bearing plate for bearing against a rock surface 136 about the bore 124, as will be explained in more detail below.

In use, the bore 124, typically of constant diameter along its length, is drilled into the rock strata 122. The distal end 114 is anchored in the bore 124 to the rock strata 122 by resin or mechanical anchors. Once the cable bolt 100 is anchored, it can be tensioned using the tensioning assembly 138 (also known as an end fitting), where the bearing plate 134, via the barrel and wedge 132 is forced onto the rock strata 122 surround the bore 124, which provides tension along the cable 100, resulting in compression on the rock strata surrounding the bore 124.

An adaptor 140 may be mounted to the proximal end 112 of the cable 100. The adaptor 140 may be configured to provide grout 120 within the hollow strand 118 or about the hollow strand 118 when it is in situ in the bore 124. Unhardened

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21206315_1(GHMtters) P109836.AU.1 settable material (e.g., grout) may be introduced in the hollow strand and to fill the bore from the distal end 114 of the cable bolt 100 to the proximal end 112. When the grout is unhardened, the reinforcing member 126 is inserted, either manually (by hand) or mechanically (by machine), into the hollow strand 118 of the cable bolt 100. The insertion takes place shortly, or in some cases immediately, after grouting has been completed before the grout has begun to cure and harden. The reinforcing member 126 may require retention. In some embodiments, the frictional engagement of the grout 120 with the reinforcing member 126 retains the reinforcing member 126 in position in the hollow strand 118. In some embodiments, the adapter 140 is used as a cap to retain the reinforcing element in the hollow strand 118.

The reinforcing member 126 displaces some of the unhardened grout during insertion. Some of the displaced unhardened grout is expelled front the bore into the cavity formed between the bearer plate 134, the end fitting 138, the cable bolt 100 and the rock face 136. Advantageously, inserting the reinforcing member 126 into the centre hollow strand 118 after grouting takes optimises the use of the hollow strand 118 by increasing its functionality from being a grout conduit to also being a vessel.

Now referring to Figs. 5 and 6, illustrated is a further embodiment of a cable bolt 200. The primary difference between the further embodiment of the cable 200 and the first embodiment of the cable bolt 100 is that the cable bolt 200 includes a further embodiment of a hollow strand 218. Like reference numerals are used for like features.

The cable bolt 200 is formed from the plurality of wound coextending flexible strands 116 as discussed above in relation to the first embodiment. As illustrated in Fig. 5, the plurality of strands 116 comprises twelve outer steel filaments 116a spiral wound about the central hollow filament 218, located axially within the cable 200. The cable bolt 200 includes two more outer steel filaments 116a than the cable bolt 100 as discussed above. As a result, the relative diameter with

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21206315_1 (GHMatters) P109836.AU.1 respect to the hollow strand 218 is adjusted accordingly such that they are close fitting about the hollow strand 218.

The hollow strand 218 includes profiling 250. The profiling 250 creates improved mechanical interlock with the settable material 120 and improved load transfer through the centre of the cable bolt 200 relative to the smooth hollow strand 118 of the first embodiment. This also contributes to increasing the tensile and shear strength of the cable bolt.

In the illustrated embodiment, the profiling 250 is in the form of corrugations which include ridges 252 and grooves 254 extending about the hollow strand 218 for its entire length. The corrugations may extend helically about the hollow strand 218. The corrugations affect both an internal surface and an external surface of the hollow strand 218.

In alternative embodiments, the profiling may be in any form which creates an uneven surface (both or one of the internal and external surface), such as ribs, texturing, ridges/groves extending in any direction etc. This forms an interlocking relationship between the cable bolt components and the hardened settable material. The profiling may extend part way along the length of the hollow strand or may extend in repeating sections that are spaced apart.

The settable material 120 is inserted into the hollow strand 218, and then the at least one reinforcing member 126 may be inserted into unhardened settable material 120 in the hollow strand 118. The unhardened settable material 120 is able to intimately fill the spaces between and surround the hollow strand 218 and the reinforcing member 126. The hollow strand 218 retains the outer filaments 116 from collapsing. The profiled hollow strand 218 improves the load transference between the outer filaments 116 and the reinforcing member 126.

Once hardened, the settable material 120 may retain the reinforcing member 126 in position in the hollow strand 218 with the bond formed by the settable material 120 between the hollow strand 218 and reinforcing member 126 allowing load transference to improve the cable bolt's 200 ability to accommodate tensile 13

21206315_1 (GHMatters) P109836.AU.1 loading. The uneven surface area created by the profiling 250 of the hollow strand 218 (e.g. the corrugations 250) creates an interlocking relationship between the cable bolt components including the outer filaments 116, the hollow strand 218 itself, the reinforcing member 126 and the settable material 120. This improves the load transference between the outer filaments 116 and the reinforcing member 126. Once the cable bolt 200 is tensioned the settable material 120 won't tend to slide out with the cable bolt 200 if the tensioned cable bolt fails. The corrugations 250 extending helically allow the corrugations to be transverse to the tensioning direction which further resists failure of the cable bolt by inhibiting relative slippage of the hollow tube relative to the reinforcing member and the cable.

In alternative embodiments, various types of settable material may be used cementitious materials formed from cement or cement like materials such as geopolymers. The settable material may also be polymeric such as polyester resins or urea silicates.

In alternative embodiment, various methods may be used to retain the at least in reinforcing member in the hollow strand such as through the end fittings and or through direct mechanical interaction between the reinforcing member(s) and the hollow strand. This may be through a keying or threaded arrangement or a frictional engagement or solely by the bonding properties of the settable material (if any) that is retained in hollow strand on fitting of the reinforcing member(s).

In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

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Claims

1. A cable bolt extends along an axis between opposite ends, the cable bolt comprising:

a settable material; and

2. A cable bolt according to claim 1, wherein the at least one reinforcing member is in the form of a longitudinal element.

3. A cable bolt according to either claim 1 or claim 2, wherein the plurality of strands includes a centre strand and the centre strand is the hollow strand.

4. A cable bolt according to claim 3, wherein the hollow strand includes profiling.

5. A cable bolt according to claim 4, wherein the profiling is in the form of corrugations of the hollow strand.

6. A cable bolt according to any one of the preceding claims, wherein the settable material bonds to both the hollow strand and the reinforcing member to allow load transference between the hollow strand and the reinforcing member.

7. A cable bolt according to any one of the preceding claims, wherein the settable material is a cementitious material or resin.

8. A cable bolt according to any one of the preceding claims, wherein the length of the at least one reinforcing member is less than the length of the cable.

9. A cable bolt according to claim 8, wherein the at least one reinforcing member is arranged to be disposed in the cable in a region vulnerable to shearing through discontinuity in the rock strata.

10. A cable bolt according to any one of the preceding claims, wherein the at least one reinforcing member is relatively inflexible compared to the cable.

11. A cable bolt according to any one of the preceding claims, wherein the at least one reinforcing member is more ductile than one or more of the cable strands.

12. A cable bolt according to any one of the preceding claims, wherein the at least one reinforcing member may be steel and/or polymeric, and may be formed as a single element or from multiple strands.

13. A cable bolt according to any one of the preceding claims, wherein the cable bolt has a distal end adapted for anchoring to rock strata, and a proximal end adapted for receiving settable material.

14. A cable bolt according to any one of the preceding claims when dependent on claim 5, further comprising an adaptor fitted to the second proximal end of the cable for facilitating the receipt of the settable material, wherein the adapter retains the at least one reinforcing member in relation to the cable bolt.

15. A cable bolt according to any preceding claim, wherein the at least one reinforcing member improves the shear capacity of the cable bolt.

16. A cable bolt according to any preceding claim, wherein the at least one reinforcing member improves the tensile capacity of the cable bolt.

17. A cable bolt assembly comprising a cable bolt according to any one of the preceding claims and a tensioning assembly mounted on an end of the cable, the tensioning assembly arranged in use to tension the cable.

18. A cable bolt assembly according to claim 17, wherein the tensioning assembly comprises an end fitting being mounted adjacent the second proximal end of the cable.

19. A cable bolt assembly according to claim 18, wherein the end fitting comprises a barrel and wedge assembly.

20. A cable bolt assembly according to any one of claims 17 to 19, wherein the tension assembly further comprises a bearer plate which is mounted to the cable between the end fitting and the distal end of the cable.

21. A method of forming a cable bolt extending along an axis between opposing ends, the method comprising:

providing at least one reinforcing member for insertion in the at least one hollow strand for increasing the load capacity of the cable bolt;

22. A method according to claim 21, further comprising disposing the hollow strand centrally between the other of the plurality of wound strands.

23. A method of installing the cable bolt comprising:

installing a cable bolt in a bore in rock substrate, the cable formed from a plurality of wound co-extending strands, and at least one the strands is a hollow strand; disposing a settable material into the hollow strand of the cable, and inserting at least one reinforcing member into the settable material in the hollow strand.

24. A method according to claim 23, wherein inserting the at least one reinforcing member disposes the at least one reinforcing member in the settable material; and

allowing the settable material to harden so that the at least one reinforcing member is retained in the harden settable material and allows load transference between the hollow strand and the at least one reinforcing member.

25. A method according to claim 24, wherein the hollow strand includes profiling.

26. A method according to claim 25, wherein the profiling is in the form of corrugations of the hollow strand.

114 100 22

14

116 16 18 20 30 130 1/4

124

24 122

12 112 Fig. 1a Fig. 1b Fig. 2

116a 118 100

126 2/4

Fig. 3

120 100 124 118 122 116 116 126 118

134 134 134 136 132 3/4

138 132 138 132 138 112 112 112 140 140 140

126

Fig. 4a Fig. 4b Fig. 4c

218 126 250 120 200 116

126 4/4

218

254 252 Fig. 5 Fig. 6