An anchoring device, a cable bolt and methods of use thereof

Abstract

A cable bolt for general stabilisation of a rock body in underground mining applications and methods of use thereof is disclosed. In one form, the cable bolt includes an anchoring device including: a body having an insertion end for insertion into a borehole defined in the rock body, an opposed outer end and a passageway extending therebetween for receiving a cable of the cable bolt therethrough; a plurality of retention prongs protruding rearwardly from the outer end of the body for engaging with a sidewall of the borehole and thereby centralising the body relative to the borehole and preventing withdrawal of the anchoring device from the borehole; and a cable retention collar connectable to the insertion end of the body for retaining the cable relative to the body.

Description

AN ANCHORING DEVICE, A CABLE BOLT AND METHODS OF USE THEREOFTECHNICAL FIELD

[0001] The present invention relates to a cable bolt for general stabilisation of a rock body in underground mining applications and methods of use thereof.BACKGROUND

[0002] Cable bolts are used in mining, tunnelling and in general stabilisation of a rock body. One use of cable bolts is in the underground mining industry where underground tunnels are excavated to facilitate mining operations. The tunnel roof spaces have to be reinforced for safety reasons. Traditionally, cable bolts are fitted into boreholes that have been pre-drilled into a rock body with one end of the bolt protruding from the rock face of the rock body. A thrust plate can then be mounted to the protruding end. The thrust plate is often used in combination with a support mesh and / or spray concrete that forms a net across the rock face so as to constrain or limit movement of the rock face in the event of a movement or failure of the rock body.

[0003] Modern safety requirements require the installation of cable bolts in any unsupported tunnel roof space exceeding 6m2. Typically, the cable bolt is anchored deep within the rock body so that it can support the rock effectively and limit movements of the rock face. Often, the cable bolt is secured within the borehole using a cementitious or resinous grout mixture that solidifies, or cures, to lock the cable bolt rigidly in position within the rock body.

[0004] A problem in general with the above process is that it is time consuming and associated with labour costs. For example, the installation process is usually undertaken in three stages spanning days to allow time for curing of the cementitious or resinous grout mixture.

[0005] Additionally, the installed cable bolts have to be manually retained in place in the drilled bore holes while the cementitious or resinous grout mixture cures thereby further adding to the labour-intensive nature of the process. Apart from the labour-intensive nature of manually retaining the cable bolts in place, the process also increases the risk of error, as the cable bolts are prone to slipping before the cementitious or resinous grout mixture cures.

[0006] It will be clearly understood that, if a prior art publication is referred to herein, this reference does not constitute an admission that the publication forms part of the common general knowledge in the art in Australia or in any other country.SUMMARY OF INVENTION

[0007] Embodiments of the present invention provide an anchoring device for a cable bolt, a cable bolt and methods of use thereof, which may at least partially address one or more of the problems or deficiencies mentioned above or which may provide the public with a useful or commercial choice.

[0008] According to a first aspect of the present invention, there is provided an anchoring device for cable bolt for supporting a rock body in underground mining, said anchoring device including: a body having an insertion end for insertion into a borehole defined in the rock body, an opposed outer end and a passageway extending therebetween for receiving a cable of the cable bolt therethrough; a plurality of retention prongs protruding rearwardly from the outer end of the body for engaging with a sidewall of the borehole and thereby centralising the body relative to the borehole and preventing withdrawal of the anchoring device from the borehole; and a cable retention collar connectable to the insertion end of the body for retaining the cable relative to the body.

[0009] According to a second aspect of the present invention, there is provided a cable bolt for supporting a rock body in underground mining, said cable bolt including: a cable having an insertion end for insertion into a borehole defined in the rock body; and an anchoring device connectable to the end of the cable for securing the cable in the borehole, said anchoring device including: a body having an insertion end for insertion into the borehole, an opposed outer end and a passageway extending therebetween for receiving the cable therethrough; a plurality of retention prongs protruding rearwardly from the outer end of the body for engaging with a sidewall of the borehole and thereby centralising the body relative to the borehole and preventing withdrawal of the anchoring device from the borehole; and a cable retention collar connectable to the insertion end of the body for retaining the cable relative to the body.

[0010] Advantageously, the anchoring device of the present invention by way of the plurality of retention prongs provides a cable bolt that is able to be inserted into a bore hole without the need for a cementitious or resinous grout mixture to be applied about the cable bolt other thanfor corrosion protection. Additionally, by way of the retention prongs, the anchoring device centralises itself relative to the borehole thereby enabling an optionally applied cementitious or resinous grout mixture to be evenly applied about the anchoring device without the need for manually maintaining the anchoring device in position. Consequently, the use of a cable bolt equipped with the anchoring device streamlines mine development thereby saving time, reducing plant and human resource costs and enhancing workplace safety by minimising manual handling and resulting subsequent error.

[0011] As indicated, the anchoring device and the cable bolt of the present invention are for use in supporting a rock body in underground mining operations. It will therefore be convenient to describe them with reference to this example application. However, a person skilled in the art will appreciate that the anchoring device and cable bolt of the present invention are capable of broader applications and may be used in a wider range of scenarios and / or integrated with various types of other mechanical equipment for retention and reinforcement purposes in related fields.

[0012] As indicated, the cable bolt includes the anchoring device as herein described and a cable coupled to the device. The cable is typically an elongate flexible metal cable configured to extend and protrude outwards of the borehole defined in the rock body.

[0013] The cable includes an insertion end coupled to the anchoring device and an opposed outer end.

[0014] The outer end is typically coupled to a thrust plate and is often used in combination with a support mesh and / or spray concrete that forms a net across the rock face so as to constrain or limit movement of the rock face in the event of a movement or failure of the rock body.

[0015] The cable is preferably a multistrand cable formed from a plurality of interwoven metal strands, preferably a multistrand steel cable.

[0016] The cable is of a length, as defined between the insertion end and the outer end, to span a length of the borehole in the rock body with the outer end at least partially protruding therefrom.

[0017] As indicated, the anchoring device includes body having an insertion end for insertion into a borehole defined in the rock body, an opposed outer end and a passage extending therebetween for receiving a cable of the cable bolt therethrough.

[0018] The body may be of any suitable size, shape and construction and may be formedfrom any suitable material or materials, typically metal material or materials, preferably spring steel. The body may be constructed using a CNC milling machine from spring steel.

[0019] The body may be of unitary construction or may be formed from two or more body pieces, preferably the former.

[0020] The body may include at least one sidewall extending between the insertion end and the outer end, preferably longitudinally.

[0021] The at least one sidewall may be curved or rounded.

[0022] The body may include an inlet opening defined in the outer end and an outlet opening defined in the insertion end. The terms “inlet opening” and “outlet opening” are used to designate a direction in which a cable of a cable bolt is threaded through the body of the anchoring device, i.e., in the “inlet opening”, through the passageway and out the “outlet opening”. Accordingly, the inlet opening and the outlet opening may be in fluid communication with the passageway for receiving the cable therethrough. The inlet opening and the outlet opening may preferably be centrally defined in the outer end and the insertion end, respectively.

[0023] The body may include any suitable cross-sectional shape. For example, the body may have a circular, oval-shaped, triangular or rectangular cross-sectional shape, preferably substantially circular.

[0024] In some embodiments, the passageway may have a constant diameter.

[0025] In other embodiments, the passageway may taper in diameter from the insertion end to the outer end, preferably gradually. In such embodiments, the passageway may have a smaller diameter at or near the outer end than a diameter at or near the insertion end.

[0026] Like the passageway, the inlet opening and the outlet opening may also be substantially circular. Preferably, the outlet opening may be of the same size as the passageway at the insertion end whereas the inlet opening may be of narrower diameter sized and shaped to enable the cable to pass therethrough.

[0027] In preferred embodiments, the body may be in the form of a barrel and the passageway may extend between and entirely through the outer end and the insertion end, preferably in fluid communication with the inlet end and the outlet end respectively defined therein. The passageway of the barrel may taper from the insertion end to the outer end, typically at a taper angle about 5°, about 6°, about 7°, about 8°, about 9° or about 10° or more.

[0028] Each of the insertion end and the outer end may include an end edge portion extending peripherally around the outlet opening and the inlet opening.

[0029] In preferred embodiments, the outer end of the body may include an outer edge portion with a centrally defined inlet opening and the insertion of the body may be defined by a rim of the sidewall of the body defining the outlet opening.

[0030] Generally, the body may be sized to fit a corresponding borehole it is received in.

[0031] For example, in some embodiments, the body may have a length, as defined between the insertion end and the outer end, of about 40mm, about 45mm, about 50mm, about 55mm, about 60mm, about 65mm, about 70mm, about 75mm, about 80mm, about 85mm, about 90mm, about 95mm, about 100mm, about 105mm, about 110mm, about 115mm, about 120mm, about 125mm, about 130mm, about 135mm, about 140mm, about 145mm or even about 150mm or more. Typically, the body may have a length of between about 55mm and about 70mm, preferably about 65mm.

[0032] The body may have an outer diameter, as measured between diametrically opposed sides of the body, of about 25mm, about 30mm, about 35mm, about 40mm, about 45mm, about 50mm, about 55mm, about 60mm, about 65mm, about 70mm, about 75mm, about 80mm, about 85mm, about 90mm, about 95mm, or even about 100mm or more. Typically, the body may have an outer diameter of between about 45mm and about 55mm.

[0033] In some embodiments, the body may include one or more flattened sidewall portions for engagement with a torque applying tool for tightening the body and the collar relative to each other. Typically, the body may include at least two flattened sidewall portions located on diametrically opposed sides of the body for engaging with a wrench, for example.

[0034] As indicated, the device includes a plurality of retention prongs protruding rearwardly from the outer end of the body for engaging with a sidewall of the borehole, centralising the body relative to the borehole and preventing withdrawal of the device from the borehole.

[0035] The device may include any suitable number of retention prongs arranged and extending in any suitable arrangement from the outer end of the body. Each retention prong may be of any suitable size, shape and construction and formed from any suitable material or materials, typically metal material or materials, preferably spring steel.

[0036] Each prong may be of unitary or separate construction with the body.

[0037] Each prong may include a proximal end, extending from, or fastened to, the outerend of the body, an opposed distal end and an elongate body extending therebetween.

[0038] The elongate body may be of tubular or solid construction, preferably the latter.

[0039] The elongate body may be defined by at least one sidewall. The at least one sidewall may be curved such that the elongate body has a substantially circular profile shape, although non-circular profile shapes, such as, e.g., a rectangular or triangular shape, are also envisaged.

[0040] Each prong may be of any suitable length as defined between the distal and proximal ends. For example, each prong may have a length of about 30mm, about 35mm, about 40mm, about 45mm, about 50mm, about 55mm, about 60mm, about 65mm, about 70mm, about 75mm, about 80mm, about 85mm, about 90mm, about 95mm, or even about 100mm or more. Typically, each prong may have a length of about 45mm and about 55mm.

[0041] In some embodiments, each prong may taper or narrow in diameter as it extends from the proximal end to the distal end.

[0042] In other preferred embodiments, each prong may be of uniform diameter as it extends from the proximal end to the distal end.

[0043] Each prong may have a diameter of about 4mm, about 5mm, about 6mm, about 7mm, about 8mm, about 9mm, about 10mm, about 1 1 mm, about 12mm, about 13mm, about 14mm, about 15mm or even more. Typically, each prong may have a diameter of between about 5mm and 10mm.

[0044] The plurality of retention prongs may generally extend from, or be fastened to, the outer end edge portion.

[0045] The plurality of prongs may include two, three, four, five, six, seven, eight, nine or even 10 prongs, typically between four and eight prongs.

[0046] The prongs may be arranged about the outer end edge portion in a spaced arrangement, preferably evenly spaced about the outer end portion.

[0047] In some embodiments, the prongs may be fastened to the outer end portion of the body with one or more mechanical fasteners, such as, e.g., threaded fasteners.

[0048] In other embodiments, the prongs and the outer end portion of the body may be connectable by a connecting mechanism or part thereof. For example, each prong may include a first part of the connecting mechanism associated with a proximal end of the prong and the outer end portion of the body may include a second part connectable to the first part of eachprong.

[0049] The connecting mechanism may include mateable make and female formations that couple or mate together, such as, e.g., by a threaded connection, an interference (snap-fit) connection, a bayonet-type connection or a friction fit-type connection.

[0050] In some such embodiments, the first part of the connecting mechanism associated with a proximal end of each prong may include a male formation configured to be inserted into, or coupled with, a female formation of the second part of the connecting mechanism associated with the outer end portion of the body.

[0051] Conversely, in other such embodiments, the first part of the connecting mechanism may include a female formation configured to at least partially receive, or be coupled with, a male formation of the second part of the connecting mechanism.

[0052] In yet other embodiments, each prong may be configured to be threadingly received in one of a plurality of corresponding holes defined about the outer end portion of the body, preferably in an evenly spaced arrangement.

[0053] Specifically, the proximal end of each prong may include a threaded portion with an external thread defined thereon configured to threadingly engage with a corresponding hole having a threaded portion with an internal thread defined thereon.

[0054] In yet other embodiments, each prong may be fixedly fastened to the outer end portion of the body using conventional welding techniques.

[0055] In some embodiments, each prong may be angled out relative to a longitudinal axis of the body such that the distal end of the prong is able to engage with a sidewall of the borehole.

[0056] Each prong may be angled out any suitable angle relative to the longitudinal axis of the body. For example, each prong may be angled outwards at an angle of about 5°, about 7.5°, about 10°, about 12.5°, about 15°, about 17.5°, about 20°, about 22.5°, about 25°, about 27.5°, about 30°, about 32.5°, about 35°, about 37.5° or even about 40° or more relative to a longitudinal axis of the body, typically between about 15° and about 30°.

[0057] In some such embodiments, the angled prongs may be evenly spaced and spirally arranged about a peripheral edge of the outer end portion of the body. In such embodiments, each prong may partially overlap an adjacent prong and distal end of each prong may extend outwards for engagement with a sidewall of the borehole. Specifically, a mid-portion of each prong may overlap an adjacent prong as each prong spirals about the peripheral edge of theouter end portion of the body.

[0058] In such embodiments, the device may further include one or more guide prongs that extend proud from the outer end portion of the body. The one or more guide prongs may assist in guiding the anchoring device when being inserted into a borehole. Additionally, the one or more guide prongs may assist in preventing the angled prongs from being bent out of their spiral arrangement. Put another way, the one or more guide prongs assist in maintaining the angled prongs in the spiral arrangement. In preferred embodiments, the device may include two guide prongs protruding from diametrically opposed sides of the outer end portion of the body.

[0059] In other embodiments, each prong may have an arcuate shaped elongate body that curves or bends outwardly from the proximal end to the distal end. The arcuate shaped elongate body may be of any suitable degree of curvature.

[0060] Advantageously, by being angled or outwardly curved, the retention prongs in use engage with a sidewall of the borehole and centralise the body relative to the borehole. In turn, this facilitates in holding the anchoring device or cable bolt in place while a cementitious or resinous grout mixture is optionally applied around and about the anchoring device or cable bolt in the borehole.

[0061] Additionally, centralising the body relative to the borehole advantageously facilitates the flowing and infiltration of the cementitious or resinous grout mixture about and around the anchoring device or cable bolt resulting in a more even application of the mixture and the formation of a stronger bond between the anchoring device or cable bolt and the sidewall of the borehole, when compared to prior art cable bolts or anchoring device that may end up resting against the sidewall of the borehole while the cementitious or resinous grout mixture is applied.

[0062] Lastly, and as mentioned, the angled or outwardly curved prongs may additionally retain the anchoring device and / or cable bolt in place within a borehole preventing the anchoring device or cable bolt from inadvertently withdrawing from the borehole before, or in the absence of, a cementitious or resinous grout mixture being applied about the anchoring device and / or the cable bolt and being allowed to cure.

[0063] As indicated, the anchoring device further includes a cable retention collar connectable to the insertion end of the body for retaining the cable relative to the body (and the anchoring device).

[0064] The cable retention collar may be of any suitable size, shape and construction and may be formed from any suitable material or materials, typically metal material or materials,preferably spring steel. The collar may be constructed using a CNC milling machine from spring steel.

[0065] The collar may be of unitary construction or may be formed from two or more collar pieces, preferably the former.

[0066] The collar may have a substantially circular shape sized and shaped to match the insertion end of the body.

[0067] In some embodiments, the collar may include an outer end wall, an inner end wall configured to abut against an insertion end portion of the body when connected thereto, at least one sidewall extending therebetween and passageway extending between and through the outer end wall and the inner end wall for receiving an insertion end of a cable threaded through the body of the device therethrough.

[0068] In other embodiments, the collar may include an outer end wall, at least one sidewall extending from the outer end wall for connection to the insertion end of the body and a passageway extending through the outer end wall for receiving an insertion end of a cable threaded through the body of the device therethrough.

[0069] The collar may include rounded or chamfered edge between the outer end wall and the at least one sidewall and / or between the inner end wall and the at least one sidewall.

[0070] The at least one sidewall may be curved or rounded.

[0071] In some embodiments, the collar may include an inlet opening defined in the inner end wall and an outlet opening defined in the outer end wall. The inlet opening and the outlet opening may be in fluid communication with the passageway for receiving the insertion end of the cable therethrough. The inlet opening and the outlet opening may preferably be centrally defined in the inner end wall and the outer end wall, respectively.

[0072] In other embodiments, the collar may include a central opening defined in the outer end wall. The central opening may be in fluid communication with the passageway for receiving the insertion end of the cable therethrough.

[0073] The collar may have any suitable cross-sectional shape. For example, the collar may have a circular, oval-shaped, triangular or rectangular cross-sectional shape. Typically, the collar may have the same cross-sectional shape as the body, preferably substantially circular.

[0074] The central opening, the inlet opening, the outlet opening and / or the passagewaymay be of any suitable, size and shape for receiving the insertion end of the cable therethrough, preferably also substantially circular.

[0075] The central opening, the inlet opening, the outlet opening and / or the passageway of the collar may have a constant diameter.

[0076] The collar and the insertion end of the body may be connectable in any suitable way, preferably releasably.

[0077] For example, in some embodiments, the collar and the insertion end of the body may be connected together by a connecting mechanism or part thereof. The connecting mechanism or part thereof may or may not be of integral formation with each of the collar and the insertion end of the body.

[0078] In some embodiments, the connecting mechanism may include a first part associated with the collar and a second part connectable to the first part associated with the insertion end of the body.

[0079] The connecting mechanism may include mateable male and female portions that couple together, such as, e.g., by a threaded connection, an interference (snap-fit) connection, a bayonet-type connection or a friction fit-type connection.

[0080] In some such embodiments, the first part of the connecting mechanism associated with the collar may include a male formation configured to be inserted into, or coupled with, a female formation of the second part of the connecting mechanism associated with the insertion end of the body.

[0081] Conversely, in other such embodiments, the first part of the connecting mechanism may include a female formation configured to at least partially receive, or be coupled with, a male formation of the second part of the connecting mechanism.

[0082] In other embodiments, the collar and the body may threadingly connect together. The collar may include a male formation protruding from the inner end wall and having an external thread defined thereon and the outlet opening defined in the insertion end of the body may have an internal thread defined on at least a portion of the internal sidewall for threadingly engaging with the male formation. Preferably, in such embodiments the passageway of the collar may extend centrally through the male formation to provide passage of the cable therethrough.

[0083] In yet other such embodiments, the collar may have an external thread defined onthe at least one sidewall for threadingly engaging with the internal thread defined in the insertion end of the body on at least a portion of the internal sidewall.

[0084] In some embodiments, cable retention collar may include one or more flattened sidewall portions for engagement with a torque applying tool for tightening the collar relative to the body. Typically, the collar may include at least two flattened sidewall portions located on diametrically opposed sides of the collar for engaging with a wrench, for example.

[0085] In some embodiments, the outer end of the collar may define an external socket formation for engaging with a torque applying tool.

[0086] As indicated, the cable retention collar is connectable to the insertion end of the body for retaining the cable relative to the body. This may be achieved in any suitable way.

[0087] Generally, the device may further include two or more wedge elements configured to be aligned and arranged within the passageway of the body to engage with, and clamp against, or constrict about, a portion of the cable received therethrough, when the cable retention collar is connected to the insertion end of the body.

[0088] Each wedge element may be of any suitable size, shape and construction to be locatable within the passageway, preferably about a periphery of the passageway.

[0089] Generally, each wedge element may include a tip, an opposed base and a wedge body extending therebetween.

[0090] The tip may be configured to be arranged at or near the outer end of the passageway of the body. Likewise, the opposed base may be configured to be arranged at or near the insertion end of the body.

[0091] Each wedge body may include an inner wall, an opposed outer wall and a pair of opposed sidewalls extending longitudinally between the tip and the base. The inner wall may preferably include a concave surface defined thereon.

[0092] In embodiments in which the passageway of the body tapers, or narrows diameter from the insertion end to the outer end, each wedge element may likewise taper in width from the base to the tip so as to enable the wedge elements to be arranged within the passageway of the body about a periphery of a portion of a cable extending therethrough in side-by-side arrangement.

[0093] Each wedge element may taper in width from the base to the tip, typically with anouter taper angle of about 5°, about 6°, about 7°, about 8°, about 9° or about 10° or more. Preferably, the outer taper angle of each wedge element may be the same as the inner taper angle of the passageway of the body.

[0094] The two or more wedge elements may include any suitable number of wedge elements configured to be arranged about a periphery of the passageway. For example, the two or more wedge elements may include two, three, four, five, six, seven, eight, nine or even 10 wedge elements, preferably two or three wedge elements.

[0095] In some embodiments, the inner wall of each wedge element may further include one or more ridges or teeth defined thereon. The one or more ridges or teeth may preferably bite into a portion of the cable received therethrough to further enhance the clamping against, or constricting about, the cable.

[0096] As indicated, the two or more wedge elements may be arranged within the body for engaging with a portion of the cable received therethrough.

[0097] In some embodiments, the wedge elements may be axially moveable relative to the passageway of the body to expand and fit about a portion of the cable when initially threaded through the body.

[0098] In such embodiments, the wedge elements may conversely be axially moveable relative to the body towards the outer end to clamp against, or constrict about, the portion of the cable when the cable retention collar is connected to the insertion end of the body, and preferably threadingly engaged.

[0099] In some embodiments, the device may further include a clamping conduit configured to be threaded over the cable between the two or more wedge elements and the cable retention collar for at least partially enhancing the axial movement of the wedge elements towards the outer end and thus enhancing the clamping or constricting of the wedge elements about the portion of the cable, when the cable retention collar is connected to the insertion end of the body, and preferably threadingly engaged.

[0100] The clamping conduit may include a pair of opposed edges and at least one sidewall extending therebetween and defining a central annulus for passage of the cable therethrough.

[0101] In some embodiments, the two or more wedge elements may further include an alignment member or mechanism for aligning the wedge elements relative to each other in the passageway of the body, preferably in a side-by-side arrangement.

[0102] Any suitable alignment member or mechanism may be used that is known in the art. For example, in some embodiments, the alignment member or mechanism may include an Ciring or clip configured to substantially align the wedge elements relative to each other yet allow expansion when fitted about, or over, the cable.

[0103] In some such embodiments, each wedge element may include a retaining groove for at least partially receiving the O-ring or clip and aligning the wedge elements relative to each other. The retaining groove may be defined in the outer wall at or near the base. The grooves may substantially align in each of the wedge elements when arranged in side-by-side arrangement about a periphery of the passageway of the body.

[0104] According to a third aspect of the present invention, there is provided a method of attaching an anchoring device according to a first aspect of the present invention to a cable of a cable bolt, said method including: threading an end of the cable through a passageway of the body of the anchoring device from the outer end to the insertion end; and fitting a cable retention collar over the end of the cable protruding from the insertion end of the body and connecting the collar to the insertion end of the body such that the cable is retained relative to the body.

[0105] The method may include one or more features or characteristics of the anchoring device as hereinbefore described.

[0106] The fitting may include arranging two or more wedge elements about a periphery of the passageway of the body and the portion of the cable received therethrough before fitting the cable retention collar over the end of the cable.

[0107] The fitting may further include threadingly engaging the cable retention collar to the insertion end of the body and applying torque to tighten the cable retention collar relative to the body and to drive the two or more wedge elements towards the outer end of the passageway so as to tighten the wedge elements about the portion of the cable received therethrough.

[0108] According to a fourth aspect of the present invention, there is provided a method of installing a cable bolt according to a second aspect of the present invention to a rock body in underground mining, said method including: inserting an insertion end of a cable with an associated anchoring device into a drilled borehole in the rock body until the insertion end and the anchoring device are located at or near an end of the borehole; and optionally, applying a cementitious or resinous grout mixture into the borehole aboutthe cable bolt.

[0109] The method may include one or more features or characteristics of the anchoring device and / or the cable bolt as hereinbefore described.

[0110] When inserting, the plurality of retention prongs of the anchoring device may extend rearwardly and thereby not impede insertion. However, the plurality of rearwardly protruding prongs may prevent withdrawal of the cable bolt from the borehole by engaging and biting into a sidewall of the borehole.[0011 1] In some embodiments, the cementitious or resinous grout mixture may be applied to form a bond about with the cable bolt with a sidewall of the borehole.

[0112] In other embodiments, the cementitious or resinous grout mixture may be applied about at least the anchoring device of the cable bolt within the borehole to protect the anchoring device from corrosion.

[0113] Any of the features described herein can be combined in any combination with any one or more of the other features described herein within the scope of the invention.

[0114] The reference to any prior art in this specification is not, and should not be taken as an acknowledgement or any form of suggestion that the prior art forms part of the common general knowledge.BRIEF DESCRIPTION OF DRAWINGS

[0115] Preferred features, embodiments and variations of the invention may be discerned from the following Detailed Description which provides sufficient information for those skilled in the art to perform the invention. The Detailed Description is not to be regarded as limiting the scope of the preceding Summary of Invention in any way. The Detailed Description will make reference to a number of drawings as follows:

[0116] Figure 1 shows a side view of an anchoring device for a cable bolt according to an embodiment of the present invention;

[0117] Figure 2 shows an exploded side view of the anchoring device as shown in Figure 1 ;

[0118] Figure 3 is a cross sectional view of a borehole with the anchoring device as shown in Figures 1 and 2 installed; and

[0119] Figure 4 is a sectional side view of a borehole in a rock body with a cable bolt including an anchoring device as shown in Figures 1 to 3, installed in the borehole;

[0120] Figure 5 is another sectional side view of a borehole in a rock body with the cable bolt as shown in Figure 4 installed and secured in place with a cementitious or resinous grout mixture;

[0121] Figure 6 is an upper perspective view of an anchoring device for a cable bolt according to another embodiment of the present invention;

[0122] Figure 7 is an end view of the anchoring device shown in Figure 6;

[0123] Figure 8 is a flow chart showing a method of fitting an anchoring device as shown in Figures 1 and 2 to cable to form a cable bolt according to an embodiment of the present invention; and

[0124] Figure 9 is a flow chart showing a method of installing a cable bolt to rock body as shown in Figures 4 and 5 according to an embodiment of the present invention.DETAILED DESCRIPTION

[0125] Figures 1 to 3 show an anchoring device (100) and Figures 4 and 5 show a cable bolt (200) including the anchoring device (100) according to an embodiment of the present invention for reinforcing tunnel roof spaces in underground mining applications.

[0126] Referring to Figure 1 , the anchoring device (100) includes a body (1 10) having an insertion end (112), an opposed outer end (114) and a passageway (not visible) extending therebetween for receiving a cable (210; not shown) of a cable bolt (200; not shown) therethrough; a plurality of retention prongs (120) protruding rearwardly from the outer end (114) of the body (1 10); and a cable retention collar (130) connectable to the insertion end (112) of the body (110) for retaining the cable (210; not shown) relative to the body (110).

[0127] Referring briefly to Figure 3, the plurality of retention prongs (120) engage with a sidewall (910) of a borehole (900) for centralising the body (110) of the device (100) relative to the borehole (900) and preventing withdrawal of the anchoring device (100) from the borehole (900).

[0128] Referring back to Figure 1 , the body (1 10) is formed from spring steel and manufactured using a CNC milling machine.

[0129] The body (1 10) is in the form of a barrel having a circular profile shape defined by acurved sidewall (1 16) extending longitudinally between the insertion end (112) and the outer end (1 14).

[0130] The body (1 10) may include an inlet opening centrally defined in the outer end (1 14) and an outlet opening defined by a rim (1 18) of the sidewall (116). The outer end (1 14) includes an outer end edge portion (1 19) extending peripherally around the inlet opening.

[0131] The passageway has a circular profile shape and extends between and entirely thought the outer end (114) and the insertion end (1 12) in fluid communication with the inlet opening and the outlet opening, respectively. The terms “inlet opening” and “outlet opening” are used to designate a direction in which a cable (210; not shown) of the cable bolt (200; not shown) is threaded through the body (1 10) of the anchoring device (100), i.e., in the “inlet opening”, through the passageway and out the “outlet opening”.

[0132] The passageway of the body (1 10) tapers from the insertion end (112) to the outer end (1 14) with a taper angle of about 7° such that the passageway has a smaller diameter at or near the outer end (114) than a diameter at or near the insertion end (1 12) of the body (100).

[0133] Generally, the body (110) is sized to fit a corresponding borehole it is received in.

[0134] As shown, the body (1 10) includes opposed flattened sidewall portions (115) for engagement with a wrench, for example, when tightening or loosening the collar (130) relative to the body (1 10).

[0135] As shown, the plurality of retention prongs (120) protrude rearwardly from the outer end (114) of the body (1 10) for engaging with a sidewall of a borehole (900; not shown), centralising the body (1 10) relative to the borehole (900; not shown) and preventing withdrawal of the device (100) from the borehole (900; not shown).

[0136] In this embodiment, the device (100) includes six prongs (120). However, it will be appreciated that the device (100) may include any suitable number of prongs (120).

[0137] The prongs (120) are made of spring steel and are of separate construction to the body (110) of the device (100).

[0138] Each prong (120) includes a proximal end (122), fastened to the outer end edge portion (119) of the body (110), an opposed distal end (124) and an elongate body (126) extending therebetween.

[0139] The elongate body (126) is of solid construction.

[0140] The elongate body (126) is defined by a single curved sidewall and each prong (120) is uniform diameter as it extends from the proximal end (122) to the distal end (124).

[0141] The prongs (120) are arranged about the outer end edge portion (1 19) in an evenly spaced arrangement and the prongs (120) are fastened to the outer end edge portion (1 19) using conventional welding techniques.

[0142] As shown, the prongs (120) are angled outwards relative to a longitudinal axis of the body (110) such that the distal end (124) of each prong (120) is able to in use engage with a sidewall of a borehole (900; not shown).

[0143] As indicated, the anchoring device (100) further includes a cable retention collar (130) connectable to the insertion end (1 12) of the body (110) for retaining a cable (210; not shown) relative to the body (1 10) (and the anchoring device (100)).

[0144] Like the body (110), the cable retention collar (130) is formed from spring steel and constructed using a CNC milling machine.

[0145] The collar (130) is unitary construction and has substantially circular shape sized and shaped to match the insertion end (112) of the body (1 10).

[0146] The collar (130) includes an outer end wall (132) having a central opening defined therein for passage of the cable (210; not shown) therethrough and at least one curved sidewall (134) orthogonally extending from a periphery of the outer end wall (132) to a lower edge (135).

[0147] The collar (130) includes a rounded edge between a periphery of the outer end wall (132) and the at least one curved sidewall (134).

[0148] The collar (130) further includes a central passageway in fluid communication with the central opening for passage of a cable (210; not shown) of the cable bolt (210; not shown) therethrough.

[0149] A lower portion of the at least one curved sidewall (134) of the collar (130) includes an external thread defined thereon for threadingly engaging with a corresponding internal thread defined on an internal surface of the passageway at or near the insertion end (1 12) of the body (1 10).

[0150] The collar (130) further includes two opposed flattened sidewall portions (135) for engagement with a wrench, for example, when tightening or loosening the collar (130) relative to the body (1 10) of the device (100).

[0151] Referring to Figure 2, the cable retention collar (130) is connectable to the insertion end (112) of the body (110) for retaining a cable (210; not shown) relative to the body (1 10).

[0152] Generally, retention of the cable (210; not shown) is achieved by two wedge elements (140) configured to be aligned and arranged within the passageway of the body (110) to engage with, and clamp against, or constrict about, a portion of the cable (210; not shown) received therethrough, when the cable retention collar (130) is threadingly fastened to the insertion end (112) of the body (110).

[0153] Each wedge element (140) is of a size, shape and construction to be locatable within the body (1 10) about a periphery of the passageway.

[0154] Each wedge element (140) includes a tip (142), an opposed base (144) and a wedge body (146) extending therebetween.

[0155] The tip (142) is configured to be arranged at or near the outer end (114) of the passageway of the body (1 10). Likewise, the opposed base (144) is configured to be arranged at or near the insertion end (1 12) of the body (1 10).

[0156] Each wedge body (140) includes an inner wall, an opposed outer wall and a pair of opposed sidewalls extending longitudinally between the tip (142) and the base (144). The inner wall includes a concave surface defined thereon.

[0157] Like the passageway of the body (1 10), each wedge element (140) likewise tapers in width from the base (144) to the tip (142) so as to enable the wedge elements (140) to be arranged within the passageway of the body (1 10) about a periphery of a portion of a cable (210; not shown) extending therethrough in side-by-side arrangement.

[0158] Each wedge element (140) tapers in width from the base (144) to the tip (142) with an outer taper angle of about 7°.

[0159] The wedge elements (140) are axially moveable relative to the passageway of the body (140) to expand and fit about a portion of the cable (210; not shown) when initially threaded through the body (110) and, conversely, to clamp against, or constrict about, the portion of the cable (210; not shown) when the cable retention collar (130) is threadingly fastened to the insertion end (112) of the body (1 10).

[0160] The device (100) further includes a clamping conduit (150) configured to be threaded over the cable (210; not shown) between the wedge elements (140) and the cable retention collar (130) for at least partially enhancing the axial movement of the wedge elements (140)towards the outer end (114) and thus enhancing the clamping or constricting of the wedge elements (140) about the portion of the cable (210; not shown), when the cable retention collar (130) is threadingly fastened to the insertion end (112) of the body (1 10).

[0161] The wedge elements (140) further include an alignment member in the form of an O-ring (148) configured to aligning the wedge elements (140) relative to each other in the passageway of the body (1 10) in a side-by-side arrangement yet allow expansion when fitted about, or over, the cable (210; not shown).

[0162] The O-ring (148) is received in a retaining groove defined in the outer wall of each wedge element (140) near the base (144).

[0163] Figures 6 and 7 show the anchoring device (100) according to another embodiment of the present invention. For convenience, features that are similar or correspond features of the aforementioned embodiment will be referenced with the same reference numerals.

[0164] Referring to Figure 6, in this embodiment, the plurality of retention prongs (120) are evenly spaced and spirally arranged around a peripheral edge of the outer end (1 14) of the body (1 10). The prongs (120) are angled at about 30° relative to a longitudinal axis of the body (1 10). The prongs (120) partially overlap adjacent prongs (120) and the distal end (124) extends outwards for engaging with a sidewall of a borehole (900; not shown).

[0165] Best shown in Figure 7, a mid-portion of each prong (120) overlaps an adjacent prong (120) as each prong (120) spirals about the peripheral edge of the outer end (1 14) of the body (110).

[0166] Referring to both Figures 6 and 7, in this embodiment the device (100) further includes a pair of guide prongs (620) protruding from diametrically opposed sides of the outer end (114) of the body (110). The guide prongs (620) assist in guiding the device (100) when being inserted into a borehole (900; not shown). Additionally, the guide prongs (620) assist in preventing the angled prongs (120) from being bent out of their spiral arrangement. Put another way, the guide prongs (620) assist in maintaining the angled prongs (120) in the spiral arrangement.

[0167] A method (700) of attaching an anchoring device (100) to a cable (210) of a cable bolt (200) as shown in Figure 4 will now be described in detail with reference to Figure 8.

[0168] At 710, an insertion end (212) of a cable (210) is threaded through the passageway of the body (1 10) of the anchoring device (100) from the outer end (1 14) to the insertion end (1 12).

[0169] Specifically, the cable (210) is threaded through the passageway and through the wedge elements (140; not visible) and the clamping conduit (150; not shown) located within the passageway of the body (1 10).

[0170] The cable (210) is a multistrand steel cable having the insertion end (212) and an opposed outer end (214).

[0171] The cable (210) is generally of a length to span a length of the borehole (900) in a rock body such that the outer end (214) protrudes for coupling with a thrust plate or the like.

[0172] At 720, the cable retention collar (130) is fitted over the end (212) of the collar and threadingly engaged to the insertion end (1 12) of the body (110) so as to drive axial movement of the wedge elements (140; not shown) and the clamping conduit (150) towards the outer end (1 14) of the passageway and tighten the wedge elements (140; not shown) about a portion of the cable received therethrough.

[0173] The collar (130) is tightened relative to the body (110) using a wrench or the like to apply torque.

[0174] A method (800) of installing a cable bolt (200) including the anchoring device (100) to a rock body in underground mining as shown in Figures 4 and 5 will now be described in detail with reference to Figure 9.

[0175] At 810, an insertion end (212) of a cable (210) with an associated anchoring device (100) of a cable bolt (200) is inserted into a drilled borehole (900) in the rock body until the insertion end (212) and the anchoring device (100) are located at or near an end of the borehole (900).

[0176] As shown, the plurality of retention prongs (120) by protruding rearwardly do not impede insertion but prevent withdrawal of the cable bolt (200) from the borehole (900) by engaging and biting into a sidewall (910) of the borehole (900). According in the embodiment shown in Figure 4, the cable bolt (200) can be used without the application of a cementitious or resinous grout mixture.

[0177] At 820, and as shown in Figure 5, optionally a cementitious or resinous grout mixture (510) can be applied into the borehole (900) about the cable bolt (200) for forming a bond between the cable bolt (200) with a sidewall of the borehole (900), and at a minimum for protecting the cable bolt (200) from corrosion.

[0178] In such embodiments, the plurality of retention prongs (120) facilitate in holding thecable bolt (200) in place while the cementitious or resinous grout mixture (510) is applied around and about the cable bolt (200) in the borehole (900).

[0179] Additionally, by centralising the body (1 10) relative to the borehole (900), the plurality of retention prongs (120) advantageously facilitate the flowing and infiltration of the cementitious or resinous grout mixture (510) about and around the cable bolt (200) resulting in a more even application of the mixture (510) and the formation of a stronger bond between the cable bolt (200) and the sidewall (910) of the borehole (900).

[0180] In the present specification and claims (if any), the word ‘comprising’ and its derivatives including ‘comprises’ and ‘comprise’ include each of the stated integers but does not exclude the inclusion of one or more further integers.

[0181] Reference throughout this specification to ‘one embodiment’ or ‘an embodiment’ means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearance of the phrases ‘in one embodiment’ or ‘in an embodiment’ in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more combinations.

[0182] In compliance with the statute, the invention has been described in language more or less specific to structural or methodical features. It is to be understood that the invention is not limited to specific features shown or described since the means herein described comprises preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims (if any) appropriately interpreted by those skilled in the art.

Claims

CLAIMS1. An anchoring device when used for a cable bolt for supporting a rock body in underground mining, said anchoring device including: a body having an insertion end for insertion into a borehole defined in the rock body, an opposed outer end and a passageway extending therebetween for receiving a cable of the cable bolt therethrough; a plurality of retention prongs protruding rearwardly from the outer end of the body for engaging with a sidewall of the borehole and thereby centralising the body relative to the borehole and preventing withdrawal of the anchoring device from the borehole; a cable retention collar connectable to the insertion end of the body for retaining the cable relative to the body, and two or more wedges configured to be aligned and arranged within the passageway of the body to engage with, and clamp against, or constrict about, a portion of the cable received therethrough, when the cable retention collar is connected to the insertion end of the body.

2. The device of claim 1 , wherein the body includes an inlet opening defined in the outer end and an outlet opening defined in the insertion end, said inlet opening and said outlet opening configured to receive the cable of the cable bolt therethrough.

3. The device of claim 2, wherein the passageway is in fluid communication with the inlet opening and the outlet opening.

4. The device of claim 3, wherein the passageway tapers in diameter from the insertion end to the outer end.

5. The device of any one of claims 2 to 4, wherein the outer end of the body includes an outer edge portion with a centrally defined said inlet opening and the insertion end of the body is defined by a rim of a sidewall of the body defining the outlet opening.

6. The device of any one of claims 1 to 5, wherein the body includes one or more flattened sidewall portions for engagement with a torque applying tool for tightening the body and the collar relative to each other.

7. The device of any one of claims 1 to 6, wherein each of the plurality of prongs includes a proximal end extending from, or fastened to, the outer end of the body, an opposed distal end and an elongate body extending therebetween.

8. The device of claim 7, wherein each of the plurality of prongs is of a unform diameter as it extends from the proximal end to the distal end.

9. The device of any one of claims 1 to 8, wherein each of the plurality of prongs are angled outwards relative to a longitudinal axis of the body at an angle relative to the longitudinal axis of the body of between about 7.5° and about 10°.

10. The device of claim 7 or claim 8, wherein each of the plurality of prongs has an arcuately shaped body that curves or bends outwards from the proximal end to the distal end.11 . The device of any one of claims 1 to 10, wherein the collar includes an outer end wall, an inner end wall configured to abut an insertion end of the body when connected thereto, at least one sidewall extending therebetween and through the outer end wall and the inner end wall for receiving an insertion end of the cable threaded through the body of the device therethrough.

12. The device of claim 11 , wherein the collar further includes an inlet opening defined in the inner end wall and an outlet opening defined in the outer end wall, said inlet opening and said outlet opening being in fluid communication with the passageway for receiving an insertion end of the cable therethrough.

13. The device of any one of claims 1 to 10, wherein the collar includes an outer end wall, at least one sidewall extending from the outer end wall for connection to the insertion end of the body and a passageway extending through the outer end wall for receiving an insertion end of the cable threaded through the body of the device therethrough.

14. The device of claim 13, wherein the collar includes a central opening defined in the outer end wall, said central opening being in fluid communication with the passageway for receiving an insertion end of the cable therethrough.

15. The device of any one of claims 2 to 14, wherein the collar is threadingly connectable to the outlet opening defined in the insertion end of the body.

16. The device of any one of claims 1 to 15, wherein each of the two or more wedge elements includes a tip, an opposed base and a wedge body extending therebetween, said wedge body including an inner wall, an opposed outer wall and a pair of opposed sidewalls extending longitudinally between the tip and the base.

17. The device of claim 16 when dependent on claim 4, wherein each of the two or more wedge elements tapers in width from the base to the tip so as to enable the wedge elements to be arranged within the passageway of the body about a periphery of a portion of the cable extending therethrough in a side-by-side arrangement.

18. The device of claim 16 or claim 17, wherein the inner wall of each of the two or morewedge elements includes one or ridges or teeth defined thereon, said one or more ridges or teeth configured to bite into a portion of the cable received therethrough to enhance the clamping against, or constricting about, the cable.

19. The device of any one of claims 1 to 18, wherein the two or more wedge elements are axially moveable relative to the passageway of the body to expand and fit about a portion of the cable when initially threaded through the body.

20. The device of claim 19, wherein the two or more wedge elements are axially moveable relative to the body towards the outer end to clamp against, or constrict about, the portion of the cable when the cable retention collar is connected to the insertion end of the body.21 . The device of claim any one of claims 1 to 20, further including a clamping conduit configured to be threaded over the cable between the two or more wedge elements and the cable retention collar for at least partially enhancing axial movement of the wedge elements towards the outer end and thus enhancing the clamping or constricting of the wedge elements about the portion of the cable, when the cable retention collar is connected to the insertion end of the body.

22. A method of attaching an anchoring device according to any one of claims 1 to 21 to a cable of a cable bolt, said method including: threading an end of the cable through a passageway of the body of the anchoring device from the outer end to the insertion end; and fitting a cable retention collar over the end of the cable protruding from the insertion end of the body and connecting the collar to the insertion end of the body so as to cause two or more wedge elements aligned and arranged within the passageway to engage with, and clamp against, or constrict about, a portion of the cable received therethrough and thereby retain the cable relative to the body.

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