AU2003281297A1 - Rock drill supports - Google Patents

Description

WO 2004/005664 PCT/IB2003/002616 ROCK DRILL SUPPORTS THIS INVENTION relates to a rock drill support for use in mining. The invention also relates to a rock drill assembly which includes the rock drill support. The invention extends to a carriage, a cradle, and a track element suitable for forming part of the rock drill assembly. The invention extends to a kit for forming the rock drill assembly and to a method of drilling into a stope face. According to the invention, there is provided a rock drill support for supporting a rock drill during drilling of boreholes into a stope face located in a stope defined between a hanging wall and a foot wall, which support includes a suspension arrangement for suspending a rock drill from the hanging wall adjacent the stope face during drilling of boreholes in a drilling direction into the stope face by the rock drill, and for permitting operative displacement of the rock drill relative to the stope face in a direction which is transverse to the drilling direction. In a preferred embodiment, the suspension arrangement includes an elongate track for connection to the hanging wall such that the lengthwise direction of the track is more or less parallel to the stope face, typically extending more or less horizontally, the suspension arrangement further including a carriage for the rock drill, the carriage being connected to the track such that when, in use, the track is connected to the hanging wall, the rock drill hangs via the carriage from the track, the carriage being displaceable, with the rock drill, along the length of the track, transversely to the drilling direction. It will be appreciated that the direction of drilling into the stope face will thus be in a direction transverse to the lengthwise direction of the track. The suspension arrangement, and particularly the carriage, will thus be configured for lengthwise displacement of the drill along the track, while permitting drilling by the drill transversely to the track. CONFIRMATION COPY WO 2004/005664 PCT/IB2003/002616 2 The support may include a plurality of elongate tensile elements, such as cables or chains, for connection between the track and supports anchored to the hanging wall, to suspend the track from the hanging wall. Typically, these anchored supports are in the form of rock bolts, each of which has a connection flange having an eye through which the associated tensile element can pass to connect the tensile element to the rock bolt. The track may comprise a series of elongate track elements which are longitudinally aligned and are connected together end-to-end in series. Conveniently, the track elements are detachably connected together, so that, once drilling of part of the stope face has been completed, the track elements at an end of the track adjacent that part can be detached, and can be re-attached to the other end of the track. The track can thus effectively migrate across the stope face, to allow drilling to progress across the stope face. In a particular embodiment of the invention, each track element is a tube which has a connection formation at one end thereof, and has a complementary connection formation at the other end thereof, the connection formations respectively being configured for engagement with the complementary connection formations of like adjacent track elements, to connect the track elements together. The track elements are typically connected together such that articulation of the connected ends of adjacent track elements is permitted, but longitudinal displacement of the track elements relative to each other is inhibited. The carriage may be connected to the track by a set of rollers which form part of the carriage and engage the track to allow movement of the carriage along the track, the set of rollers suspending the remainder of the carriage from the track. The support may include a brake mechanism for braking movement of the carriage along the track. In a particular embodiment, the remainder of the carriage is connected to the set of rollers to pivot about an operatively more or less horizontal pivot axis which is transverse, e.g. normal, to the lengthwise direction of the track, the centre of gravity of the carriage and a rock drill supported on the carriage being located to one side of the pivot axis, in the lengthwise direction of the track, and a brake shoe being located on the carriage on the other side of the pivot axis for engagement with the track, such that, WO 2004/005664 PCT/IB2003/002616 3 when the carriage and a rock drill hang freely from the track, the brake shoe is urged against the track, automatically to restrict movement of the carriage along the track by engagement of the brake shoe with the track. The carriage is thus constructed such that, in a free-hanging condition, movement of the carriage along the track is restricted by a braking mechanism which employs the weight of the carriage and/or the rock drill. It should be appreciated, that, in this free-hanging condition of the carriage, a force which urges the brake shoe towards the track is provided by the mass of the carriage and of the drill, the carriage acting as a first order lever having its fulcrum at the pivot axis. In use, the brake mechanism can be released by pivotally displacing the carriage about the pivot axis such that the brake shoe is displaced away from engagement with the track. The support may include a locking mechanism for unlockably locking the carriage in position on the track. Conveniently, the locking mechanism forms part of the brake mechanism, the locking mechanism, for instance, including a tensioning arrangement for varying the force urging the brake shoe into contact with the track. In a particular embodiment of the invention, this tensioning arrangement includes a flexible tensile element, such as a chain, which is fast with the carriage at one end of the chain, the chain passing over the track, when viewed in the lengthwise direction of the track, and the chain being adjustably connected to the carriage at or adjacent the other end of the chain, such that tension in the chain which urges the carriage, and hence its brake shoe, against the track can be varied. In use, tension in the chain, and thus a clamping force exerted by the chain to clamp the carriage to the track, is variable in response to variation in the effective length of the chain by operation of the tensioning arrangement. Instead, the locking mechanism may include a cam mechanism which is operable by a pivotal handle to lock the carriage in position on the track. The carriage may comprise a hanger assembly connected to the track, and a cradle for supporting a rock drill, the cradle being connected to the hanger assembly for pivotal displacement relative to the hanger assembly about an operatively upright pivot WO 2004/005664 PCT/IB2003/002616 4 axis. In addition, the cradle may be mounted on the hanger assembly such that it is operatively vertically displaceable relative to the hanger assembly, to vary the vertical position of a rock drill supported on the cradle, in use. The cradle may be mounted on the hanger assembly such that the cradle is displaceable between, on the one hand, a position in which a boom assembly on which a rock drill is supported is mountable on the cradle for drilling into the stope face, transversely to the track, to one side of the hanger assembly along the lengthwise direction of the track and, on the other hand, another position in which the boom assembly is mountable on the cradle for drilling into the stope face, transversely to the track, to an opposite side of the hanger assembly along the lengthwise direction of the track. In such case, the cradle may be pivotally displaceable about a pivot axis which is transverse to the vertical and which is operatively transverse to the stope face. The support may include an anchoring mechanism for, in use, anchoring the carriage in position to restrict movement of the carriage away from the stope face, transversely to the lengthwise direction of the track, owing to drilling forces acting between the drill and the stope face. In a particular embodiment of the invention, the anchoring mechanism includes an anchor memberwhich projects operatively downwardly away from the carriage for engagement with the foot wall. Instead, the anchor mechanism may include an anchor member which projects operatively upwardly away from the carriage for engagement with the hanging wall. The anchor member is typically connected to the carriage for displacement between an anchoring position in which the anchor member projects away from the carriage for anchoring of the carriage, and a stored position in which movement of the carriage away from the stope face is unrestricted by the anchor member. Instead, or in addition, the anchoring mechanism may be arranged to restrict pivotal displacement of the carriage relative to the track about a pivot axis longitudinally aligned with the lengthwise direction of the track. The invention extends to a rock drill assembly which includes: a rock drill support as defined above; and WO 2004/005664 PCT/IB2003/002616 5 a rock drill mounted on the rock drill support such that the rock drill is suspended from the hanging wall during drilling of boreholes into the stope face in a drilling direction, and such that displacement of the rock drill in a direction transverse to the drilling direction is permitted. The invention further extends to a track element for forming part of a rock drill support, the track element including: an elongate body for engagement by a carriage on which a rock drill is supported, to suspend the rock drill from the body of the track element and to permit displacement of the carriage along the elongate body of the track element; at least one attachment formation fast with the body for attachment of the body to associated tensile elements connected to a hanging wall of a mine stope, so that the body of the track element is, in use, suspended from a said hanging wall bythe tensile elements; and a connection formation at one end of the body, and a complementary connection formation at the opposite end of the body, the connection formations respectively being configured for engagement with the complementary connection formations of like adjacent track elements, to connect the track elements together end-to-end and form a longitudinally extending track along which a said carriage is displaceable. The connection formations permit detachable and re-connectable connection together of adjacent track elements. Typically, the elongate body is a steel tube having attachment formations in the form of connection eyes projecting operatively upwardly therefrom. The invention also extends to a carriage for forming part of a rock drill support, which carriage includes: a body on which a rock drill is supportable such that the drilling of boreholes in a drilling direction into a stope face by the rock drill is permitted; and a track follower, such as a set of rollers, which is mounted on the body for engagement, in use, with an elongate track which is suspended from a hanging wall, extending more or less parallel to a said stope face, such that the body of the carriage is suspended from the track and is displaceable along the length of the track.

WO 2004/005664 PCT/IB2003/002616 6 The body of the carriage may be constructed for permitting vertical displacement of a rock drill supported thereon relative to a track from which the carriage is, in use, suspended. The invention further extends to a cradle for forming part of a rock drill support, which cradle includes: a rock drill mounting formation for mounting of a rock drill on the cradle; and a connection formation for mounting the cradle on a hanger assembly suspended from an elongate track which is, in turn, suspended from a hanging wall in a mine stope, such that the cradle, and hence the rock drill mounted thereon, is operatively vertically displaceable on a hanger assembly to which it is mounted, to vary, in use, the height of the rock drill. The cradle may be constructed for mounting on a hanger assembly to permit angular displacement of a rock drill supported on the cradle about an operatively upright pivot axis between a drilling position in which a rock drill mounted on the cradle is oriented for drilling in a drilling direction into a stope face extending more or less parallel to an elongate track from which the cradle is suspended, and a displacement position in which said rock drill is oriented such that is longitudinally aligned with a said elongate track. The invention yet further provides a kit for forming a rock drill assembly, which kit includes: a plurality of elongate track elements which are connectable by associated tensile elements to a hanging wall of a stope underground in a mine, the track elements being connectable together end-to-end in series to form an elongate track which is suspended from a said hanging wall; and a carriage which is engageable with a said track element such that, when the track element is suspended from the hanging wall, the carriage hangs from the track element and is movable along the track element, the carriage being configured for supporting a rock drill for drilling of boreholes into a stope face in a direction transverse to the lengthwise direction of the track element. The carriage typically comprises a hanger assembly which has mounted thereon a set of rollers for engagement with a said track element, the carriage further WO 2004/005664 PCT/IB2003/002616 7 comprising a cradle assembly to which a rock drill is connected or connectable for operative vertical displacement of the cradle relative to the hanger assembly. The invention further extends to a method of drilling into a stope face located in a stope defined between a hanging wall and a foot wall, which method includes: suspending a rock drill from the hanging wall adjacent the stope face during drilling of boreholes in a drilling direction into the stope face by means of the rock drill; and displacing the rock drill, while the rock drill is suspended from the hanging wall, in a direction transverse to the drilling direction between different drilling positions. The method may include moving the rock drill along an elongate track from which the rock drill is suspended, the lengthwise direction of the track being more or less parallel to the stope face and the track being suspended from the hanging wall, e.g. so as to extend more or less horizontally. The method may in such case include the prior step of connecting a plurality of track elements to associated anchored supports in the hanging wall, each track element being connected to the associated anchored supports by tensile elements, such that the track elements are arranged end-to-end in series and are connected together to form the elongate track. The invention will now be further described, by way of example, with reference to the accompanying diagrammatic drawings, in which: Figure 1 is a schematic plan view of a rock drill assembly in accordance with the invention suspended in a stope of any underground mine; Figure 2 is a three-dimensional view, from above, of part of the rock drill assembly of Figure 1, on an enlarged scale; Figure 3 is a three-dimensional view, from below, of the rock drill assembly of Figure 2; Figure 4 is plan view of the rock drill assembly of Figure 2; Figure 5 is an end elevation of the rock drill assembly of Figure 2; Figure 6 is a side elevation of the rock drill assembly of Figure 2, showing the stope; and WO 2004/005664 PCT/IB2003/002616 8 Figure 7 is a schematic, partly exploded, three-dimensional view of a further embodiment of a rock drill assembly in accordance with the invention. In the drawings, reference numeral 10 generally indicates a rock drill assembly in accordance with the invention. The assembly 10 includes rock drill 12 for drilling into a stope face 14 located at the end of a stope 16 defined between a hanging wall 18 and a foot wall 20 (Figure 6) and bordered by a pair of side walls 15 (Figure 1). The assembly 10 further includes a support for a rock drill, the support comprising a suspension arrangement 22 (see particularly Figures 5 and 6) for suspending the drill 12 from the hanging wall 18 adjacent the stope face 14 during the drilling of boreholes (not shown) into the stope face 14. The suspension arrangement 22 includes an elongate track 24 (best seen in Figure 1) which is suspended from the hanging wall 18, such that the lengthwise direction of the track 24 is more or less parallel to the stope face 14. The track 24 comprises a plurality of elongate track elements 26 which are connected together end-to end in series. Each track element 26 is a steel tube which has a connection formation at one end thereof and a complementary connection formation at the other end thereof. In this example, the connection formations comprise a slot 28 in an end wall 30 of the tube 26 (Figures 2 and 3), and a hammer-shaped key 32 projecting from an end wall 34 of the tube 26 at the end of the tube 26 opposite end wall 30, the key 32 including an elongate head 33 which is parallel to the associated end wall 34. The track elements 26 are connected together end-to-end by engagement of the slot 28 in the end wall 30 of one track element 26 with the key 32 of a neighbouring track element 26, a stem of the key 32 passing through the slot 28, and the lengthwise directions of the key head 33 and the slot 28 being transverse to each other, so that relative longitudinal displacement of the track elements 26 away from each other is prevented by interference between the key head 33 and the end wall 30. The track elements 26 are suspended from the hanging wall 18 by elongate flexible tensile elements in the form of a plurality of lengths of chain 36, each track element 26 having an eye 38 at each end thereof for connecting associated chains 36 to the track element 26. For ease of illustration, the chains 36 are omitted in Figures 1 and 4. Each WO 2004/005664 PCT/IB2003/002616 9 chain 36 is connected, at one end thereof, to an associated eye 38, and, at the other end thereof, to a support in the form of a rock bolt 40 (Figure 6) anchored to the hanging wall 18, an end link of the chain 36 passing through an opening (not shown) in a connection flange 42 of the rock bolt 40. Again, a rock bolt 40 is shown in Figure 6 only, for ease of illustration. The suspension arrangement 22 further includes a carriage 44 on which the rock drill 12 is supported, the carriage 44 being suspended from the track 24, so that the rock drill 12 hangs from the track 24, via the carriage 44. The carriage 44 is mounted on the track 24 by a set of wheels or rollers 46, which engage the track 24 to allow movement of the carriage 44 along the track 24, but which resist displacement of the carriage 44 downwardly away from track 24, thus suspending the carriage 44 from the track 24 in mobile fashion. In this example, there are two wheels 46 which are rotatably connected to a base 48 such that the wheels 46 are respectively rotatable about axes of rotation which are at an angle of about 90 0 to each other and which are respectively inclined more or less equally relative to the vertical. The wheels 46 are spaced apart and the base 48 extends below the track 24 (Figure 6), so that the wheels 46 can roll past the eyes 38, which project upwardly from the track 24, without the wheels 46 or base 48 snagging the eyes 38 or chains 36. The carriage 44 is generally F-shaped when the assembly 10 is viewed in a direction normal to the stope face 14 but opposite to the direction in which it is viewed in Figure 5, the carriage 44 having an elongate more or less vertical leg 50 and two vertically spaced apart transverse legs 52, 54 projecting transversely from the same side of the vertical leg 50, so that each transverse leg 52, 54 is more or less horizontal and parallel to the track 24. In this example, the main body of the carriage 44 is formed from mild steel tubing, in particular, 2% inch schedule 40 pipe. The uppermost transverse leg 52 is pivotally connected to the wheel base 48, to be pivotally displaceable relative to the base 48, and therefore to the track 24, about a horizontal pivot axis 56 which is normal to the length of the track 24 and hence to the stope face 14.

WO 2004/005664 PCT/IB2003/002616 10 The rock drill 12 comprises an elongate boom assembly 58 which is mounted on the lower transverse leg 54 of the carriage 44 such that the lengthwise direction of the boom assembly 58 is horizontal and is normal to the stope face 14. The rock drill 12 further comprises a rig 60, which is carried in the boom assembly 58 and which is directed at the stope face 14. The rock drill 12 includes an actuating mechanism (not indicated) for displacing the rig 60 longitudinally in the boom assembly 58, towards or away from the stope face 14. The boom assembly 58 is removably mounted on an end of the lower transverse leg 54 remote from the vertical leg 50, the end of the transverse leg 54 being received spigot/socket fashion in a socket provided on the boom assembly 58. The boom assembly 58 is locked in position on the transverse leg 54 by a quick-release locking mechanism 74 which is operable by a locking mechanism handle 62. The lower transverse leg 54, and thus the boom structure 58, are connected to the vertical leg 50 to be both vertically displaceable along the vertical leg 50, and angularly displaceable about a pivot axis 65 which is vertical and more or less co-axial with the longitudinal axis of the vertical leg 50. This articulated connection is achieved by a sleeve 64 which is fast with the lower transverse leg 54 and which is fitted around the vertical leg 50, the sleeve 64 being slidable along the length of the vertical leg 50. The sleeve 64 is supported in position by a separate tubular sleeve base 70 which is received on the vertical leg 50, beneath the sleeve 64, the sleeve base 70 being anchored against longitudinal vertical displacement relative to the vertical leg 50. The sleeve 64 and sleeve base 70 are provided with opposed and abutting annular flanges 72, the flanges 72 being rotatably slidable relative to each other, to permit angular displacement of the sleeve 64 about the vertical leg 50, while the sleeve 64 is supported on the sleeve base 70, the flange 72 of the sleeve 64 sliding on the flange 72 of the sleeve base 70. The vertical leg 50 has a plurality of locating openings 68 (Figures 2, 3 and 6) therein, the openings 68 being spaced in series along the length of the leg 50. The sleeve base 70 is adjustably locatable in a desired vertical position by a locating pin 66 which is received in a selected opening 68, the locating pin 66 passing through aligned openings in a tubular wall of the of the sleeve base 70, to anchor the sleeve base 70 against longitudinal displacement relative to the vertical leg 50. The locking pin 66 is in the WO 2004/005664 PCT/IB2003/002616 11 form of a drop-pin which automatically locks in position when passed through an opening 68. The sleeve 64 is rotationally keyed to the vertical leg 50 in a similar manner, a locking pin (not shown) passing through aligned openings in the tubular wall of the sleeve 64 and through an opening 68 in the vertical leg 54. It will be appreciated that the spacing between the openings 68 is such that when the sleeve base 70 is located in position by the locating pin 66 which passes through one of the openings 68, the openings in the sleeve 64 will be in register with another said opening 68. It will be seen from the description above that the carriage 44 consists of, on the one hand, a hanger assembly comprising the L-shaped member which provides the vertical leg 50 and the transverse leg 52, as well as the base 48 mounted on the upper leg 52, and, on the other hand, a cradle assembly consisting of the transverse leg 54 and the boom assembly 58, the cradle assembly being displaceably mounted on the hanger assembly by means of the sleeve 64. The rock drill assembly 10 includes a brake mechanism for braking movement of the carriage 44 along the track 24. In this example, the brake mechanism comprises a brake shoe 76 of a material having a high coefficient of friction, the brake shoe 76 being mounted on the upper transverse leg 52 of the carriage 44, adjacent an end of the upper transverse leg 52 remote from the vertical leg 50. As can best be seen in Figure 5 of the drawings, the rock drill 12 is located more or less in vertical alignment with the pivot axis 56 about which the hanger assembly is pivotally displaceable. The upper transverse leg 52 is effectively a first order lever having its fulcrum at the pivot axis 56. The combined centre of gravity of the carriage 44 and rock drill 12 lies on the same side of the pivot axis 56 as the vertical leg 50, so that when the carriage 44 hangs freely from the wheel base 48, the brake shoe 76 is urged upwardly by gravity against the track 24, to brake the carriage 44 by friction between the brake shoe 76 and the track 24. Although not illustrated in the drawings, the assembly can include a locking mechanism which co-operates with the braking mechanism to lock the carriage 44 in position on the track 24, the locking mechanism comprising a tensioning arrangement for varying the normal force urging the brake shoe 76 on to the track 24, as described above.

WO 2004/005664 PCT/IB2003/002616 12 The rock drill assembly 10 further includes an anchoring mechanism 78 for anchoring the carriage 44 in position to restrict movement of the carriage 44 away from the stope face 14 in response to drilling forces acting between the drill rig 60 and the stope face 14 during drilling. In this example, the anchoring mechanism 78 comprises an angled anchor leg 80 which is vertically displaceably housed in a vertically extending tube 82 fast with and laterally spaced from the sleeve 64. The anchor leg 80 is vertically displaceable between an anchoring position in which the leg 80 projects downwardly away from the carriage 44 and engages the foot wall 20, to abut against the foot wall 20 when drilling forces, in use, urge the carriage 44 away from the stope face 14, and a stored position (shown in the drawings) in which the leg 80 is raised to be out of engagement with the foot wall 20, to permit movement of the carriage 44 along the track 24. The anchor leg 80 is locked in a desired position by a screw-threaded key 84 which is received in a complementary threaded hole through the tubular wall of the tube 82. The application of torque to the key 84 screws the key 84 into or out of engagement with the anchor leg 80, to lock the leg 80 in position, or to release the leg 80, as the case may be. In use, the rock drill assembly 10 is used to drill boreholes (not shown) into the stope face 14. First, the track 24 is formed by suspending one of the track elements 26 from the hanging wall 18 by connecting the chains 36 of that track element 26 to associated rock bolts 40 anchored to the hanging wall 18, the track element 26 being more-or-less parallel to the stope face 14. Thereafter, another track element 26 is connected end-to-end to the suspended track element 26 by bringing the other track element 26 into longitudinal alignment with the suspended track element 26, the eyes 38 of the other track element 26 being oriented horizontally, so that the head 33 of the key 32 of the other track element 26 is in register with the slot 28 in the end wall 30 of the suspended track element 26. The other track element 26 is then displaced towards the suspended track element 26 to pass the head 33 through the aligned slot 28, afterwhich the other track element 26 is angularly displaced about its longitudinal axis such that the eyes 38 are directed upwardly, the slot 28 and the key head 33 thus being transverse to each other, to connect the track elements 26 together, as described above.

WO 2004/005664 PCT/IB2003/002616 13 The other track element 26 is thereafter suspended from the hanging wall 18 by chains 36 connected to associated rock bolts 40. Typically, the rock bolts 40 have earlier been connected to the hanging wall 18 adjacent the stope face 14 in accordance with conventional mining practice, these conventional rock bolts 40 being used for suspension of the track elements 26. As many track elements 26 are connected together as is required to span the stope face 14, thereby forming the track 24. The assembly 10 thus provides a mono-rail stope jig. The carriage 44 is suspended from the track 24 by sliding the carriage 44 on to the track 24 from one end thereof, the track 24 being received in a space defined between the wheels 46 mounted on the wheel base 48 and the upper transverse leg 52. The carriage 44 is displaced along the track 24 to a desired position relative to the stope face 14, the wheels 46 rolling on the track 24. To displace the carriage 44, an operator (not shown) pivotally displaces the carriage 44 about the pivot axis 56 by lifting the vertical leg 50 somewhat, so that the brake shoe 76 is disengaged from the track 24 to permit movement of the carriage 44 along the track 24. When the carriage 44 is in the desired position, the vertical leg 50 is released, so that the brake shoe 76 is automatically urged by gravity against the track 24, to brake the carriage 44 against displacement along the track 24. When the carriage 44 is in position relative to the stope face 14, the vertical position of the boom assembly 58, and thus the drill rig 60, are adjusted by vertically sliding the sleeve base 70 to a desired height, and locating it in position on the vertical leg 50 by passing the locating pin 66 through the appropriate opening 68 in the vertical leg 50. Similarly, the sleeve 64 of the lower transverse leg 54 is keyed against angular displacement relative to the vertical leg 50 by passing the associated locking pin through openings in the sleeve 64 and the registering openings 68 in the vertical leg 50. The anchor leg 80 is then released by loosening the key 84, causing the leg 80 to drop into engagement with the foot wall 20, after which the anchor leg 80 is locked in position by tightening of the key 84. When the carriage 44 is thus anchored in position, the rock drill 12 is operated to drill a borehole into the stope face 14, the drill rig 60 being actuated by an WO 2004/005664 PCT/IB2003/002616 14 actuating mechanism forming part of the rock drill 12 to displace the drill rig 60 along the boom assembly 58 towards and into the stope face 14. To drill another drill hole, the height of the rock drill 12 is adjusted by adjusting the vertical position of the sleeve 70 on the vertical leg 50, and/or the carriage 44 is displaced along the track 24 to a new position. To permit displacement of the carriage 44 along the track 24 between different drilling positions, the anchor leg 80 is raised to its stored position each time the carriage 44 is to be moved to a new position along the track 44. Once at a desired new position, the anchor leg 80 is lowered into abutment with the foot wall 20. To facilitate movement of the carriage 44 along the track 24 without snagging of the rock drill 12 on the stope face 14, keying of the sleeve 64 to the vertical leg 50 is released by withdrawing the locking pin from the sleeve 64, and the lower transverse leg 54 is angularly displaced about the pivot axis 65 to a position where the lengthwise direction of the rock drill 12 is more or less parallel to the stope face 14, the flange 72 of the sleeve 64 sliding on the flange 72 of the sleeve base 70. The articulation of the carriage 44 about the vertical leg 50 is also useful to manoeuvre the carriage 44 and rock drill 12 past any obstructions in the path of the carriage 44. In Figure 7 of the drawings, reference numeral 90 shows a further embodiment of a rock drill assembly in accordance with the invention, like reference numerals indicating like parts in Figures 1 to 6 and in Figure 7, unless otherwise indicated. The assembly 90 corresponds largely to the rock drill assembly 10 of Figures 1 to 6, with the main distinctions set out below. The boom assembly 58 is not mounted on the lower transverse leg 54 by means of a quick release mechanism, but instead rests on the lower transverse leg 54 bayonet-fashion. The boom assembly 58 thus has a pair of operatively vertically extending downwardly open slots 92 for mating engagement with the transverse leg 54. The transverse leg 54 in turn has a pair of axially spaced circumferentially extending radially outwardly projecting abutment flanges 94 which are spaced apart a somewhat greater distance than the transverse spacing between the slots 92 of the boom assembly 58, so that when, in use, the boom assembly 58 rests on the leg 54 between the flanges 94, lateral movement of the boom assembly 58 along the leg 54 is inhibited by abutment WO 2004/005664 PCT/IB2003/002616 15 against the flanges 94. To disengage the boom assembly 58 from the leg 54, the boom assembly 58 is simply lifted off the leg 54 until the slots 92 are clear of the leg 54. Furthermore, the transverse leg 54 is mounted on the sleeve 64 such that the leg 54 is angularly displaceable about a pivot axis 96 which extends more or less 450 downwardly, away from the stope face 14. This permits mounting of the boom assembly 58 on the transverse leg 54 such that the boom assembly 58 can be located on either side of the vertical leg 50. For instance, in the condition shown in Figure 7, the boom assembly 58 can be lifted from the leg 54, after which the transverse leg 54 can be swung through 1800 about pivot axis 96. Thereafter, the boom assembly 58 can again be engaged with the transverse leg 54, so that the boom assembly 58 is located on the opposite side of the vertical leg 50, in the lengthwise direction of the track 24, but the rock drill 12 still faces the stope face 14. The assembly 10 includes a locking mechanism 98 for releaseably locking the transverse leg 54 in position relative to the sleeve 64. The rock drill assembly 90 has an anchor mechanism 178 which is configured for engagement with the hanging wall 18, instead of with the foot wall 20 as is the case with the assembly 10 of Figures 1 - 6. Thus, an anchor member in the form of an anchor leg 180 is slidably located in a vertically extending mounting tube 182 to project operatively vertically away from the remainder of the assembly 90. The anchor leg 180 is vertically slidable in the tube 182 to permit optional displacement thereof into abutment with the hanging wall 18. Although, in this example, the anchor leg 180 is mounted on the sleeve 64 of the cradle, via the tube 182, the anchor leg 180 can in other embodiments of the invention be displaceably mounted on the vertical leg 50 of the hanger assembly, so that the vertical position of the anchor leg 180 is unaffected by operative displacement of the sleeve 64, and thus the cradle, along the vertical leg 50. In addition, the anchor leg 180 can be mounted on the hanger assembly such that a transverse horizontal spacing between the anchor leg 180 and the track 22 is adjustable. A further feature of the rock drill assembly 90 of Figure 7 is that it includes a locking mechanism 100 for locking the carriage 44 in position on the track 24. In this example, the locking mechanism 100 comprises a pair of opposed clamping jaws 102 which are located on opposite sides of the track 24, the locking mechanism 100 being mounted on the upper transverse leg 52, between the set of wheels 46 and the brake shoe WO 2004/005664 PCT/IB2003/002616 16 76. The jaws 102 are displaceable towards each other by mechanical advantage means to clamp the track element 24 between them, and thus to limit movement of the carriage 44 relative to the track element 24 because of a clamping force exerted by the jaws. In another example of the invention, which is not shown, the locking mechanism can be in the form of an eccentric cam arrangement which is operable by means of a cam handle. Although not evident from Figure 7 of the drawings, the wheels 46 are of polyurethane, having crowned or convex part-spherical radially outer surfaces which engage the track 24. It is an advantage of the rock drill assembly 10, 90 as described with reference to the drawings that operation of the assembly 10, 90 in an underground mining environment is less labour intensive than that of conventional rock drill assemblies, where tracks on which the rock drills are displaceably supported are laid on the foot wall 20. The support surface provided by the foot wall 20 is often highly irregular, which hinders quick installment of these tracks. This problem is obviated by suspending the drill 12 from the hanging wall 18, using existing rock bolts 40 to connect the track to the hanging wall 18. It is thus not necessary to transport the heavy equipment needed to install a track on the foot wall 20 to the stope face 14. In comparison, the track elements 26, which are hollow, are light-weight. Once the track 24 has been installed, the rock drill 12 can be operated by a single operator, which is not the case with conventional assemblies, bearing in mind the considerable weight of the rock drill 12. It is possible, when installing the track 12, to tailor the lengths of the chains 36 such that the track 24 slopes slightly downwardly in the direction in which the drill 12 is to be moved. Such a sloping track permits the operator to move the carriage 44 along the track 24 by simply lifting the vertical leg 50 somewhat, to release the brake 76 and to allow the carriage 44 to move along the track 24 under gravity. It is envisaged that the carriage 44 can be provided with a powered drive means for driving the carriage 44 along the track 24, for instance being a rack-and-pinion arrangement in which the track acts as a toothed rack and the carriage 44 is provided with a driven pinion.

WO 2004/005664 PCT/IB2003/002616 17 The rock drill assembly 10, 90 also permits drilling of a plurality of spaced holes which are closer to being perfectly parallel than conventional drilling methods, thus enhancing toe-burden consistency and improving blasting efficiency. This is particularly the case when anchoring of the assembly 90 occurs against the hanging wall 18, so that swinging of the cradle away from the stope face is restricted to a minimum.

Claims (36)

1. A rock drill support for supporting a rock drill during drilling of boreholes into a stope face located in a stope defined between a hanging wall and a foot wall, which support includes a suspension arrangement for suspending a rock drill from the hanging wall adjacent the stope face during drilling of boreholes in a drilling direction into the stope face by the rock drill, and for permitting operative displacement of the rock drill relative to the stope face in a direction which is transverse to the drilling direction.

2. A rock drill support as claimed in claim 1, in which the suspension arrangement includes an elongate track for connection to the hanging wall such that the lengthwise direction of the track is more or less parallel to the stope face, the suspension arrangement further including a carriage for the rock drill, the carriage being connected to the track such that when, in use, the track is connected to the hanging wall, the rock drill hangs via the carriage from the track, the carriage being displaceable, with the rock drill, along the length of the track, transversely to the drilling direction.

3. A rock drill support as claimed in claim 2, which includes a plurality of elongate tensile elements for connection between the track and supports anchored to the hanging wall, to suspend the track from the hanging wall.

4. A rock drill support as claimed in claim 2 or claim 3, in which the track comprises a series of elongate track elements which are longitudinally aligned and are connected together end-to-end in series.

5. A rock drill support as claimed in claim 4, in which the track elements are detachably connected together.

6. A rock drill support as claimed in claim 4 or claim 5, in which each track element has a connection formation at one end thereof, and has a complementary connection formation at the other end thereof, the connection formations respectively being configured for engagement with the complementary connection formations of like adjacent track elements, to connect the track elements together. WO 2004/005664 PCT/IB2003/002616 19

7. A rock drill support as claimed in any one of claims 2 to 6 inclusive, in which the carriage is connected to the track by a set of rollers which form part of the carriage and engage the track to allow movement of the carriage along the track, the set of rollers suspending the remainder of the carriage from the track.

8. A rock drill support as claimed in claim 7, in which the remainder of the carriage is connected to the set of rollers to pivot about an operatively more or less horizontal pivot axis which is transverse to the lengthwise direction of the track, the centre of gravity of the carriage and a rock drill supported on the carriage being located to one side of the pivot axis, in the lengthwise direction of the track, and a brake shoe being located on the carriage on the other side of the pivot axis for engagement with the track, such that, when the carriage and a rock drill hang freely from the track, the brake shoe is urged against the track, automatically to restrict movement of the carriage along the track by engagement of the brake shoe with the track.

9. A rock drill support as claimed in any one of claims 2 to 8 inclusive, which includes a locking mechanism for unlockably locking the carriage in position on the track.

10. A rock drill support as claimed in any one of claims 2 to 9 inclusive, in which the carriage comprises a hanger assembly connected to the track, and a cradle for supporting a rock drill, the cradle being connected to the hanger assembly for pivotal displacement relative to the hanger assembly about an operatively upright pivot axis.

11. A rock drill support as claimed in claim 10, in which the cradle is mounted on the hanger assembly such that it is operatively vertically displaceable relative to the hanger assembly, to vary the vertical position of a rock drill supported on the cradle, in use.

12. A rock drill support as claimed in claim 10 or claim 11, in which the cradle is mounted on the hanger assembly such that the cradle is displaceable between, on the one hand, a position in which a boom assembly on which the rock drill is supported is mountable on the cradle for drilling into the stope face, transversely to the track, to one side of the hanger assembly along the lengthwise direction of the track and, on the other hand, another position in which the boom assembly is mountable on the cradle for drilling WO 2004/005664 PCT/IB2003/002616 20 into the stope face, transversely to the track, to an opposite side of the hanger assembly along the lengthwise direction of the track.

13. A rock drill support as claimed in any one of claims 2 to 12 inclusive, which includes an anchoring mechanism for, in use, anchoring the carriage in position to restrict movement of the carriage away from the stope face, transversely to the lengthwise direction of the track, owing to drilling forces acting between the drill and the stope face.

14. A rock drill support as claimed in claim 13, in which the anchoring mechanism includes an anchor memberwhich projects operatively downwardly away from the carriage for engagement with the foot wall.

15. A rock drill support as claimed in claim 13, in which the anchoring mechanism includes an anchor member which projects operatively upwardly away from the carriage for engagement with the hanging wall.

16. A rock drill support as claimed in claim 14 or claim 15, in which the anchor member is connected to the carriage for displacement between an anchoring position in which the anchor member projects away from the carriage for anchoring of the carriage, and a stored position in which movement of the carriage away from the stope face is unrestricted by the anchor member.

17. A rock drill support as claimed in any one of claims 13 to 16 inclusive, in which the anchoring mechanism is arranged to restrict pivotal displacement of the carriage relative to the track about a pivot axis which is longitudinally aligned with the track.

18. A rock drill assembly which includes: a rock drill support as claimed in any one of claims 1 to 17 inclusive; and a rock drill mounted on the rock drill support such that the rock drill is suspended from the hanging wall during drilling of boreholes into the stope face in a drilling direction, and such that displacement of the rock drill in a direction transverse to the drilling direction is permitted. WO 2004/005664 PCT/IB2003/002616 21

19. A track element for forming part of a rock drill support, the track element including: an elongate body for engagement by a carriage on which a rock drill is supported, to suspend the rock drill from the body of the track element and to permit displacement of the carriage along the elongate body of the track element; at least one attachment formation fast with the body for attachment of the body to associated tensile elements connected to a hanging wall of a mine stope, so that the body of the track element is, in use, suspended from a said hanging wall bythe tensile elements; and a connection formation at one end of the body, and a complementary connection formation at the opposite end of the body, the connection formations respectively being configured for engagement with the complementary connection formations of like adjacent track elements, to connect the track elements together end-to-end and form a longitudinally extending track along which a said carriage is displaceable.

20. A track element as claimed in claim 19, in which the connection formations permit detachable and re-connectable connection together of adjacent track elements.

21. A carriage for forming part of a rock drill support, which carriage includes: a body on which a rock drill is supportable such that the drilling of boreholes in a drilling direction into a stope face by the rock drill is permitted; and a track follower which is mounted on the body for engagement, in use, with an elongate track which is suspended from a hanging wall, extending more or less parallel to a said stope face, such that the body of the carriage is suspended from the track and is displaceable along the length of the track.

22. A carriage as claimed in claim 21, in which the body of the carriage is constructed for permitting vertical displacement of a rock drill supported thereon relative to a track from which the carriage is, in use, suspended.

23. A cradle for forming part of a rock drill support, which cradle includes: a rock drill mounting formation for mounting of a rock drill on the cradle; and a connection formation for mounting the cradle on a hanger assembly suspended from an elongate track which is, in turn, suspended from a hanging wall in a mine stope, WO 2004/005664 PCT/IB2003/002616 22 such that the cradle, and hence the rock drill mounted thereon, is operatively vertically displaceable on a hanger assembly to which it is mounted, to vary, in use, the height of the rock drill.

24. A cradle as claimed in claim 23, which is constructed for mounting on a said hanger assembly to permit angular displacement of a rock drill supported on the cradle about an operatively upright pivot axis between a drilling position in which a rock drill mounted on the cradle is oriented for drilling in a drilling direction into a stope face extending more or less parallel to an elongate track from which the cradle is suspended, and a displacement position in which said rock drill is oriented such that is longitudinally aligned with a said elongate track.

25. A kit for forming a rock drill assembly, which kit includes: a plurality of elongate track elements which are connectable by associated tensile elements to a hanging wall of a stope underground in a mine, the track elements being connectable together end-to-end in series to form an elongate track which is suspended from a said hanging wall; and a carriage which is engageable with a said track element such that, when the track element is suspended from the hanging wall, the carriage hangs from the track element and is movable along the track element, the carriage being configured for supporting a rock drill for drilling of boreholes into a stope face in a direction transverse to the lengthwise direction of the track element.

26. A kit as claimed in claim 25, in which the carriage comprises a hanger assembly which has mounted thereon a set of rollers for engagement with a said track element, the carriage further comprising a cradle assembly to which a rock drill is connected or connectable for operative vertical displacement of the cradle relative to the hanger assembly.

27. A method of drilling into a stope face located in a stope defined between a hanging wall and a foot wall, which method includes: suspending a rock drill from the hanging wall adjacent the stope face during drilling of boreholes in a drilling direction into the stope face by means of the rock drill; and WO 2004/005664 PCT/IB2003/002616 23 displacing the rock drill, while the rock drill is suspended from the hanging wall, in a direction transverse to the drilling direction between different drilling positions.

28. A method as claimed in claim 27, which includes moving the rock drill along an elongate track from which the rock drill is suspended, the lengthwise direction of the track being more or less parallel to the stope face and the track being suspended from the hanging wall.

29. A method as claimed in claim 28, which includes the prior step of connecting a plurality of track elements to associated anchored supports in the hanging wall, each track element being connected to the associated anchored supports by tensile elements, such that the track elements are arranged end-to-end in series and are connected together to form the elongate track.

30. A rock drill support as claimed in claim 1, substantially as herein described and illustrated.

31. A rock drill assembly as claimed in claim 18, substantially as herein described and illustrated.

32. A track element as claimed in claim 19, substantially as herein described and illustrated.

33. A carriage as claimed in claim 21, substantially as herein described and illustrated.

34. A cradle as claimed in claim 23, substantially as herein described and illustrated.

35. A kit as claimed in claim 25, substantially as herein described and illustrated.

36. A method as claimed in claim 27, substantially as herein described and illustrated.