AU2019208454A1 - Improvements in or relating to rock bolts - Google Patents

Abstract

The present invention provides a rock bolt (14) comprising a cable (21) formed from multiple wound strands. The rock bolt also comprises a sleeve (16) surrounding the cable along at least portions of the cable, and multiple collars (17) spaced along the sleeve. Each collar being fitted on a different lengthwise region of the sleeve. The present invention also provides an elongate member (15) having a plurality of rock bolts connected in an end to end relationship.

Description

IMPROVEMENTS IN OR RELATING TO ROCK BOLTS

TECHNICAL FIELD

[0001 ] The present invention relates to rock bolts and/or pre-cursor products from which rock bolts are formed or divided.

BACKGROUND ART

[0002] Any document, reference, patent application or patent cited in this text is expressly incorporated herein in their entirety by reference, which means that it should be read and considered by the reader as part of this text. That the document, reference, patent application or patent cited in this text is not repeated in this text is merely for reasons of conciseness.

[0003] The following discussion of the background art is intended to facilitate an understanding of the present invention only. The discussion is not an acknowledgement or admission that any of the material referred to is or was part of the common general knowledge as at the priority date of the application.

[0004] Rock bolts are commonly used to secure and support the walls and roof of underground mine tunnels and other unstable earth formations. Typically, the process of installation involves multiple holes being drilled into the rock face of the tunnel roof and walls, with the holes reaching into deeper and often more stable rock formations than found at the rock face. The drilled holes are then enlarged by boring, before the rock bolts are inserted therein and anchored to the inner end of their respective bore hole. The rock bolts typically span the length of their respective bore holes, reinforcing the rock face in order to prevent inward collapse due to fracture, failure, or breaking apart.

[0005] Whilst not being an admission of common general knowledge, Figures 1 and 2 show a form of prior art rock bolt, generally designated 10. The prior art rock bolt 10 includes a stiff bonded cable 1 1 of fixed length, and a collar 12 tightly swaged directly and forcefully to the cable 1 1. The cable 1 1 itself comprises a central solid metal strand 13a with six peripheral strands 13b of solid metal wound therearound . [0006] Although such prior art rock bolts 10 can be useful in reinforcing rock faces, they can also suffer from various drawbacks or disadvantages. These drawbacks/ disadvantages are also commonplace in a variety of different types of prior art rock bolts. For instance, prior art rock bolts 10 tend to be manufactured in fixed lengths. The fixed length nature of the product limits its versatility and applicability to different types of rock formations. This means that either the fixed length product may not be useful to the terrain encountered, or where multiple versions of product are available with different fixed lengths, large numbers of each length of the product may need to be purchased, transported to, and stored at the rock site, to ensure sufficient variability of product is available and on hand to meet the demands of the site as they are encountered. Such fixed length prior art rock bolts may also need to be installed manually on site, or may require different machines for installation of each of the different lengths. Consequently, fixed length products such as prior art rock bolt 10 can prove costly to manufacture, and expensive to purchase and time consuming to install.

[0007] Additionally, overly forceful or tight swaging of the collars 12 directly to the cable of prior art rock bolts 10 can cause cable damage, potentially affecting the integrity of the product, and causing excessive yielding of the cable at portions adjacent to the collars. Prior art rock bolts 10 also require tensioning after installation.

SUMMARY OF INVENTION

[0008] Thus, it may be advantageous to provide a new rock bolt or rock bolt precursor product which reduces, limits, overcomes, or ameliorates some of the problems, drawbacks, or disadvantages associated with prior art devices, or provides an effective alternative to such devices.

[0009] In one aspect, the invention provides a rock bolt comprising: a cable comprising multiple wound strands; a sleeve surrounding the cable along at least portions of the cable; and multiple metal collars spaced along the sleeve, each collar being fitted on a different lengthwise region of the sleeve. [0010] The metal collars may be spaced along the cable at regular spaced intervals, at unevenly spaced intervals or a combination of both. The spacing of the collars is dependent on the geographical characteristics of the rock formation the rock bolt is to be used to stabilise.

[001 1 ] The collars may divide the cable into separate load bearing sections or regions.

[0012] In another aspect, the invention provides a rock bolt portion comprising: a de-bonded metal cable, the cable comprising a flexible member received in a sleeve; one or more collars received on the cable and spaced along the sleeve, each collar being swaged thereon; wherein adjacent collars divide the cable into separate load bearing sections that are adapted to be placed under differing loads when internally supporting a rock structure.

[0013] In another aspect, the invention provides a continuous member for producing multiple rock bolts, the member comprising: a continuous cable comprising multiple wound strands; multiple flexible sleeves, each sleeve surrounding a portion of the cable at a different region along its length; and multiple metal collars evenly or unevenly spaced along each of the sleeves, each collar being fitted on a different lengthwise region of its respective sleeve and at least partly surrounding the sleeve, wherein the member is divisible into shorter lengths to form a plurality of rock bolts. [0014] The member and the cable may be continuous in that the continuous member/cable is longer than the length of one rock bolt, as determined by its application. While the continuous member/cable will have a first end and a second end, the continuous member/cable provides a multiple number of rock bolts in an end to end attachment.

[0015] The cable may be at least partly de-bonded.

[0016] In another aspect, the invention provides a rock bolt comprising: a de-bonded metal cable, the cable comprising a flexible member surrounded by a sleeve; multiple collars evenly and/or unevenly spaced along the sleeve, each collar being swaged on a different lengthwise region of the sleeve and wholly surrounding the sleeve, each collar comprising rounded internal and external surfaces, the internal surface comprising a crimped portion which grips the flexible sleeve; and wherein adjacent collars divide the cable into separate load bearing sections that are adapted to be placed under differing loads when internally supporting a rock structure.

[0017] The rock bolt may comprise a stopper fitted to an end of the cable, the end of the cable being adapted to be received in a borehole.

[0018] The flexible member may comprise a central strand and peripheral strands wound around the central strand.

[0019] The sleeve may comprise a generally wall of circular cross section defining a central passage through which the cable extends. [0020] In another aspect, the invention provides a member for producing multiple rock bolts, the member comprising: a de-bonded metal cable, the cable comprising a central strand and peripheral strands wound around the central strand; the cable also comprising multiple flexible sleeves, each sleeve wholly surrounding the cable at a different region along its length, each sleeve comprising a wall of circular cross section defining a central passage through which the cable extends; multiple metal collars evenly and/or unevenly spaced along each of the sleeves, one or more of the collars being swaged on each different lengthwise region of its respective sleeve and wholly surrounding the sleeve, each collar comprising rounded internal and external surfaces, the internal surface comprising a crimped portion which grips its respective sleeve; and wherein the member is divisible or sectionable into shorter lengths, each or many of which lengths form single respective rock bolts.

[0021 ] The member may comprise multiple stop members fitted at evenly and/or unevenly spaced regions along the length of the cable, wherein one or more collars are located therebetween, each stop member being positioned to define the start of an adjacent rock bolt to be produced or divided from the member.

[0022] In another aspect, the invention provides a rock bolt comprising a cable, one or more sleeves surrounding at least lengthwise portions of the cable, and at least one collar surrounding the one or more sleeves, the at least one collar being swaged thereon. [0023] The cable may comprise metal and a sleeve therearound, or around lengthwise portions of the cable. It may be a de-bonded cable, or partly de-bonded cable. Thus, in some forms the cable is entirely de-bonded, while in other forms, one or more sections of the cable are de-bonded and one or more other sections are bonded. The de-bonded cable, or de-bonded cable sections, may offer some increased protection to the cable. The de-bonded cable, or de-bonded cable sections, may offer some increased flexibility, stretching, and/or movement of the cable itself in comparison to conventional cables

[0024] The cable may comprise multiple strands or threads. The strands may be solid. There may be one strand arranged centrally with multiple peripheral strands arranged around the central strand. The strands may wind around a central axis or the central strand. Thus, the cable may have a spiral appearance.

[0025] The sleeve may be a flexible sleeve, or at least flexible in parts thereof. It may wholly surround the cable. The sleeve may comprise a tubular body and/or an enclosing wall. The body may define a central passage for the cable to extend therethrough. There may be a single sleeve which spans a majority of the length of the cable. In another form, multiple sleeves may enclose separate longitudinal sections of the cable. The cable may fit snugly within the sleeve.

[0026] The collar may comprise metal. It may be a rigid collar. In one form, the collar comprises a tubular body. The collar, or tubular body, may define a central aperture for passage of the sleeve. The tubular body may comprise internal and external surfaces. The internal surface may be generally rounded. The external surface may take any shape as is required but is generally rounded. The internal surface may comprise an attachment or gripping or friction portion. The attachment or gripping or friction portion may grip the debonded cable when the collar is swaged, crimped or otherwise caused to engage the debonded cable. An interference fit may be formed between the collar and the debonded cable . [0027] There may be at least one collar. Thus, there may be multiple collars. The collars may be spaced along the length of the debonded cable. Thus, each collar may be disposed on a different lengthwise section or region of the sleeve. In one form, the collars are located at evenly spaced intervals. In another form, the collars are spaced unevenly along the length of the sleeve. In another form, the collars are spaced along the length of the sleeve at a combination of evenly and unevenly spaced intervals. The, or each, collar may be swaged onto the debonded cable. Swaging of the collar onto the debonded cable may result in compression of the debonded cable.

[0028] In another aspect, the invention provides an extended elongated member from which a multiple of rock bolts may be formed, the elongated member comprising: an extended cable and, at least one sleeve surrounding the cable. The cable and the at least one sleeve may be as defined previously for a single rock bolt, although the cable of the extended elongated member may be longer, allowing for its division into shorter lengths, each, or many, of which lengths may be used as a cable for a single rock bolt. Where there are multiple sleeves surrounding different length portions of the cable, some or all the sleeves may be provided at lengths which remain the same upon formation or division out of the rock bolts.

[0029] In another form, the elongated member comprises a single sleeve which extends along the entire length of the cable.

[0030] The elongated member may comprise multiple collars fitted along the at least one sleeve. The elongated member may further comprise a stop member fitted at a region of the sleeve that will form/define an inner end of a rock bolt produced from the elongated member. There may be multiple stop members fitted at evenly or unevenly spaced regions along the length of the sleeve, each stop member forming an inner end of a respective rock bolt produced from the elongated member. The stopper may have internal teeth to grip the cable, and ensures the cable can yield to maximum strength. The position of the stoppers may be included along the elongated member based on the planned rock bolt lay out for a particular application.

[0031 ] The elongated member may be divided into shorter lengths. Each, or many, of the lengths may form single respective rock bolts. [0032] In another aspect, the invention provides a rock bolt assembly incorporating a rock bolt as herein before described.

[0033] The present invention provides an elongate member supporting a plurality of collars and stoppers thereon such that the elongate member comprises a number of interconnected rock bolts in an end to end configuration, wherein the elongate member comprises a cable received in a sleeve or having a plurality of sleeves spaced along the length of the cable.

[0034] The rock bolt or rock bolt portion may be adapted to receive other rock bolt components, such as a base plate, as are currently incorporated in other rock bolts/rock bolt assemblies.

BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Further features of the present invention are more fully described in the following description of several non-limiting embodiments thereof. This description is included solely for the purposes of exemplifying the present invention. It should not be understood as a restriction on the broad summary, disclosure or description of the invention as set out above. The description will be made with reference to the accompanying drawings in which:

Figure 1 is a side perspective view of a portion of a prior art rock bolt;

Figure 2 is an end perspective view of the prior art rock bolt of Figure 1 ;

Figure 3 is a side perspective view of a portion of a rock bolt in accordance with an embodiment of the present invention;

Figure 4 is a magnified side perspective view of the rock bolt shown in Figure 3;

Figure 5 is a further magnified side perspective view of the rock bolt shown in Figure 3;

Figure 6 is an end perspective view of the rock bolt of Figure 3; and

Figure 7 is a perspective view of a coil of a precursor product from which rock bolts are divided. In the drawings like structures are referred to by like numerals throughout the several views. The drawings shown are not necessarily to scale, with emphasis instead generally being placed upon illustrating the principles of the present invention.

DESCRIPTION OF EMBODIMENTS

[0036] Referring to Figures 3 to 6, there is shown a portion of a rock bolt 14, in accordance with an embodiment of the invention. The rock bolt portion 14 is representative of a non-limiting configuration of a rock bolt. Such a rock bolt can also incorporate known features of rock bolts as would be understood by the person skilled in the art. For instance the rock bolt may incorporate a support plate at an exposed end of the rock bolt (once installed).

[0037] The rock bolt 14 comprises a flexible, elongated member 15, comprising a flexible sleeve 16 surrounding a cable 21 , and, in this instance, multiple metallic collars 17 surrounding the sleeve 16 at different regions along the members length. The rock bolt potion shown in the figures of the present embodiment depict three collars 17. However, it is to be appreciated that the rock bolt can incorporate any number of collars and may have the sleeve extended along the entire length of the cable 21 , or only along those portions one or more collars are to be secured.

[0038] The member 15 comprises multiple solid metal strands 18. In the example shown, seven elongated strands 18 are provided - one central strand, and six peripheral strands surrounding the central stand. The peripheral strands wind around the central strand to form the cable 21 , which cable 21 has a spiraled appearance (see Figure 7).

[0039] The sleeve 16 is tubular in shape, having a side wall 19 of circular cross section. The sleeve 16 defines a central circular passage 20 (see Figure 6) through which the strands 17 of the cable 21 extend. In the embodiment shown, the sleeve surrounds much, if not all, of the length of the cable 21. As noted above, in other embodiments the sleeve may only be located along spaced length portions of the cable 21 . [0040] Each collar 17 comprises a tubular body 18 defining a central passage 22 (see Figure 6) through which the elongated member 15 passes. The tubular body 18 has a generally rounded inner or internal surface 23 which is adapted to surround and contact the sleeve 16, and a generally rounded outer or external surface 24. The inner surface 23 may be caused to grippingly engage the elongated member 15 as a result of swaging during production of the rock bolt 14. The external surface 24 may be indented or otherwise formed to assist in retaining the rock bolt in position after installation.

[0041 ] Although not illustrated in the drawings, the rock bolt 14 may further comprise a stopper fixed at or near what will be an end of the rock bolt. The end being that which is placed most deeply into a bore hole in the rock face. The intent of the stopper is to anchor the rock bolt relative to the base of the bore hole. The stopper has internal teeth for gripping the cable. The stopper is adapted to grippingly engage the elongate member 15 with more force than which the collars grip the elongate member 15.

[0042] Additionally, the rock bolt 14 may comprise a face plate (not shown) fixed at or near a second or external end thereof. In use, the external end of the rock bolt 14 projects beyond the opening of the bore hole in which the rock bolt is received, with the face plate abutting against the surrounding rock face.

[0043] The rock bolt 14 comprises multiple sections 27 (see for example 27i, 27ii, and 27iii in Figure 3) located between adjacent collars 17, the innermost collar and the stopper (not shown), and the outer most collar 17 and the face plate (not shown). Separation of the elongate member 15 into sections 27 enables differing loads to be isolated by the different sections 27, potentially causing the different sections to undergo differing tensions and yields when in use.

[0044] Referring now to Figure 7, there is shown an extended length of an elongated member, generally designated 25, wound into a coil and bound circumferentially by spaced holding straps 26. The elongated member 25 comprises an extended length of cable 21 of the type discussed above, and a plurality of sleeves 1 16 spaced along the length of the cable 21. [0045] The elongated member 25 undergoes a swaging process whereby a plurality of collars and a plurality of stoppers are swaged onto the elongated member 25 at the desired positions. The collar/stoppers positions are cutomisably based on desired rock bolt configurations. The elongate member 25, with collars and stoppers swaged thereon, will then comprise a number of interconnected rock bolts in an end to end configuration.

[0046] One of the plurality of stoppers is swaged directly and forcefully onto what will become an inner end of each rock bolt. This is to say further stoppers are swaged onto the elongate member 25 at or near what will become inner ends of the rock bolt once divided from the elongate member 25.

[0047] Swaging of collars 17 and/or stoppers may take place off-site, such as at the manufacturer’s factory, based on a customers’ specified requirements. The elongated member 25, with collars and stoppers, may also be cut to desired lengths of rock bolt at the factory. However, it is also envisaged that the continuous elongated member 25, with collars and stoppers, could be transported to the site of installation and cut to the desired lengths of rock bolt during installation. The elongated member 25 are cut on-site into rock bolt lengths that fit the particular bore holes present in the rock formations. A boring machine may be used to bore out drilled holes in the rocks on-site, and fill the holes with grout. The machine may also install the rock bolt and cut the rock bolt from the length of the elongated member 25 before moving on to the next position.

[0048] Given the customisation of rock bolts available, a single machine may be used to drill and fill each bore hole with grout and securely insert a rock bolt 14 with its inner end, which supports one of the stoppers, positioned within the base of the bore hole. The face plate at the outer exposed end of the rock bolt 14 abuts against the surrounding rock. No pre-tensioning of the rock bolt 14 is required, nor is tensioning required post installation. The installation procedure with the exemplary rock bolt 14 can be relatively quick and easy in comparison to installation of fixed length prior art rock bolts 10, which often require manual installation, or the use of multiple machines.

[0049] The ability to tailor each rock bolt 14 with as many collars 17 as required can facilitate or optimize improved load transfer compared with prior art rock bolts, with potentially greater localized movement, and bi-directional yield capabilities. The multiple collar 17 arrangement can also be advantageous in that if the cable 15 shears at one point or section 27, another portion or section 27, or other sections, of the member 25 remain under tension enabling continued support for the surrounding rock. As a result there is no need to pre-tension or tension the rock bolt after installation.

[0050] Additional benefits of the present invention include: rock bolt isolates localised movement within the rock formation it is installed; collars do not damage cable compared to collars swaged directly to cable; collars do not need to be swaged with as much force as prior art, therefore less damage to cable; rock bolt installed by machine rather than manually; rock bolt does not need to be tensioned after installation; rock bolt can include as many collars as needed which enables a better transfer of loads. Also if cable shears at one point the remainder still holds the rock; rock bolt easier and quicker to install than prior art; rock bolt yields in both directions; only require single machine for installation.

[0051 ] Modifications and variations such as would be apparent to the skilled addressee are considered to fall within the scope of the present invention. The present invention is not to be limited in scope by any of the specific embodiments described herein. These embodiments are intended for the purpose of exemplification only. Functionally equivalent products, formulations and methods are clearly within the scope of the invention as described herein. [0052] Reference to positional descriptions, such as lower and upper, or inner and outer, are to be taken in context of the embodiments depicted in the figures, and are not to be taken as limiting the invention to the literal interpretation of the term but rather as would be understood by the skilled addressee.

[0053] The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms “a”, “an” and“the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms“comprise”,“comprises,”“comprising,” “including,” and“having,” or variations thereof are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

[0054] Although terms such as first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as“first,”“second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.

Spatially relative terms, such as“inner,”“outer,”“beneath”,“below”,“lower”,“above”, “upper” and the like, may be used herein for ease of description to describe one element or feature’s relationship to another element(s) or feature(s) as illustrated in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as“below” or “beneath” other elements or features would then be oriented“above” the other elements or features. Thus, the example term“below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

Claims (32)

1. A rock bolt comprising: a cable comprising multiple wound strands; a sleeve surrounding the cable along at least portions of the cable; and multiple metal collars spaced along the sleeve, each collar being fitted on a different lengthwise region of the sleeve.

2. The rock bolt according to claim 1 wherein the metal collars are spaced along the cable at regular spaced intervals, at unevenly spaced intervals or a combination of both, wherein the collars divide the cable into separate load bearing sections or regions.

3. A rock bolt portion comprising: a de-bonded metal cable, the cable comprising a flexible member received in a sleeve; one or more collars received on the cable and spaced along the sleeve, each collar being swaged thereon; wherein adjacent collars divide the cable into separate load bearing sections that are adapted to be placed under differing loads when internally supporting a rock structure.

4. A continuous member for producing multiple rock bolts, the member comprising: a continuous cable comprising multiple wound strands; multiple flexible sleeves, each sleeve surrounding a portion of the cable at a different region along its length; and multiple metal collars evenly or unevenly spaced along each of the sleeves, each collar being fitted on a different lengthwise region of its respective sleeve and at least partly surrounding the sleeve, wherein the member is divisible into shorter lengths to form a plurality of rock bolts.

5. The continuous member according to claim 4 wherein the cable is at least partly de-bonded.

6. A rock bolt comprising: a de-bonded metal cable, the cable comprising a flexible member surrounded by a sleeve; multiple collars evenly and/or unevenly spaced along the sleeve, each collar being swaged on a different lengthwise region of the sleeve and wholly surrounding the sleeve, each collar comprising rounded internal and external surfaces, the internal surface comprising a crimped portion which grips the flexible sleeve; and wherein adjacent collars divide the cable into separate load bearing sections that are adapted to be placed under differing loads when internally supporting a rock structure.

7. The rock bolt according to claim 7 comprising a stopper fitted to an end of the cable, the end of the cable being adapted to be received in a borehole.

8. The rock bolt according to claim 6 or 7 wherein the flexible member comprises a central strand and peripheral strands wound around the central strand.

9. The rock bolt according to claim 6, 7 or 8 wherein the sleeve comprises a generally wall of circular cross section defining a central passage through which the cable extends.

10. A member for producing multiple rock bolts, the member comprising: a de-bonded metal cable, the cable comprising a central strand and peripheral strands wound around the central strand; the cable also comprising multiple flexible sleeves, each sleeve wholly surrounding the cable at a different region along its length, each sleeve comprising a wall of circular cross section defining a central passage through which the cable extends; multiple metal collars evenly and/or unevenly spaced along each of the sleeves, one or more of the collars being swaged on each different lengthwise region of its respective sleeve and wholly surrounding the sleeve, each collar comprising rounded internal and external surfaces, the internal surface comprising a crimped portion which grips its respective sleeve; and wherein the member is divisible or sectionable into shorter lengths, each or many of which lengths form single respective rock bolts.

1 1. The member according to claim 10 comprising multiple stop members fitted at evenly and/or unevenly spaced regions along the length of the cable, wherein one or more collars are located therebetween, each stop member being positioned to define the start of an adjacent rock bolt to be produced or divided from the member.

12. A rock bolt comprising a cable, one or more sleeves surrounding at least lengthwise portions of the cable, and at least one collar surrounding the one or more sleeves, the at least one collar being swaged thereon.

13. The rock bolt according to claim 12 wherein the cable comprises a metal member and the one or more sleeves therearound, or around

lengthwise portions of the cable such that the cable is a de-bonded cable, or partly de-bonded cable.

14. The rock bolt according to claim 12 or 13 wherein the cable comprises multiple strands whereby one strand is arranged centrally with multiple peripheral strands arranged around the central strand such that the strands wind around a central axis or the central strand to provide the cable with a spiral appearance.

15. The rock bolt according to claim 12, 13 or 14 wherein each of the one or more sleeves is a flexible sleeve, or at least flexible in parts thereof and wholly surround the cable.

16. The rock bolt according to any one of claims 12 to 15 wherein each of the one or more sleeves comprises a tubular body and/or an enclosing wall, the body defining a central passage for the cable to extend therethrough.

17. The rock bolt according to any one of claims 12 to 16 whereby when there is a single sleeve it spans a majority of the length of the cable, and when there are multiple sleeves each sleeve encloses separate

longitudinal sections of the cable.

18. The rock bolt according to any one of claims 12 to 17 wherein the cable fits snugly within the sleeve.

19. The rock bolt according to any one of claims 12 to 18 wherein each collar comprises a metal rigid collar.

20. The rock bolt according to claim 19 wherein each collar comprises a tubular body and defines a central aperture for passage of the sleeve.

21. The rock bolt according to claim 20 wherein the tubular body comprises internal and external surfaces, the internal surface being generally rounded while the external surface can take any shape as is required.

22. The rock bolt according to claim 21 wherein the internal surface comprises an attachment or gripping or friction portion which grips the debonded cable when the collar is swaged, crimped or otherwise caused to engage the debonded cable, whereupon an interference fit is formed between the collar and the debonded cable.

23. The rock bolt according to any one of claims 12 to 22 wherein there are multiple collars wherein each collar is spaced along the length of the debonded cable such that each collar is disposed on a different lengthwise section or region of the sleeve.

24. The rock bolt according to claim 23 wherein the collars are located at evenly spaced intervals, are spaced unevenly along the length of the sleeve or are spaced along the length of the sleeve at a combination of evenly and unevenly spaced intervals.

25. The rock bolt according to any one of claims 12 to 24 wherein each collar is swaged onto the debonded cable whereby swaging of the collar onto the debonded cable results in compression of the debonded cable.

26. An extended elongated member from which a multiple of rock bolts are formed, the elongated member comprising: an extended cable and, at least one sleeve surrounding the cable, the elongated member comprising multiple collars fitted along the at least one sleeve.

27. The elongated member according to claim 26 further comprising a stop member fitted at a region of the sleeve that will form/define an inner end of a rock bolt produced from the elongated member.

28. The elongated member according to claim 27 wherein there are multiple stop members fitted at evenly or unevenly spaced regions along the length of the sleeve, each stop member forming an inner end of a respective rock bolt produced from the elongated member.

29. The elongated member according to claim 28 is adapted to be divided into shorter lengths to form single respective rock bolts.

30. A rock bolt assembly incorporating a rock bolt according to any one of claims 1 to 3, 6 to 9 or 12 to 25.

31. An elongate member supporting a plurality of collars and stoppers thereon such that the elongate member comprises a number of

interconnected rock bolts in an end to end configuration, wherein the elongate member comprises a cable received in a sleeve or having a plurality of sleeves spaced along the length of the cable.

32. A rock bolt according to any one of claims 1 to 3, 6 to 9 or 12 to 25 where in the rock bolt is adapted to receive other rock bolt components, such as a base plate, as are currently incorporated in other rock bolts/rock bolt assemblies.