WO2013001351A2

WO2013001351A2 - Mucking system

Info

Publication number: WO2013001351A2
Application number: PCT/IB2012/001294
Authority: WO
Inventors: Stefan Edward HAYDEN
Original assignee: MUCKING SYSTEMS SA
Current assignee: MUCKING SYSTEMS SA
Priority date: 2011-06-29
Filing date: 2012-06-29
Publication date: 2013-01-03
Anticipated expiration: 2013-12-29
Also published as: WO2013001351A3

Abstract

A mucking module, for use with a hopper, which includes a conveyor beam which overlies the hopper, the conveyor beam including formations whereby the conveyor beam can be supported on the hopper and idlers for supporting part of a load-carrying conveyor belt, a plurality of downwardly extending legs engaged with the conveyor beam and wherein the legs are extensible into contact with ground adjacent the hopper thereby to elevate the conveyor beam and so allow the hopper to move independently of the conveyor beam.

Description

MUCKING SYSTEM

BACKGROUND OF THE INVENTION

[0001] This invention relates to a mucking or waste ore removal system which can be used underground, in the development of a tunnel, or on surface, during the construction of a deep rail cutting, or the like. These applications are exemplary only and are non-limiting.

[0002] In underground mining fragmented rock, displaced in a blasting operation, must be cleared before a development end can again be drilled and blasted. This situation is encountered when an elongate tunnel is constructed. A similar situation prevails, on surface, when a cutting is made through rock between two spaced locations.

[0003] The removal of fragmented rock to expose a fresh rock face, so that further blasting can take place, can be a laborious process. If an access path to the rock face is made wide enough to accommodate, say, two rail tracks which are side-by- side then mucking can be expedited, for unloaded hoppers (also referred to as "cars") can be positioned individually or as a train on one set of rails, and loaded hoppers can be positioned individually or as a train on the other set of rails. The cost of an excavation is, however, directly dependent on the proportions of the excavation and, in many instances, it is not economically justified to excavate to such an extent that more than one set of rail tracks can be accommodated.

[0004] A typical situation therefore in which mucking takes place, is one in which a single railway line is advanced along an excavation which is progressed by successive, sequential, drilling, blasting and mucking operations at a development end. At a working face rock which is blasted free is loaded into a single hopper, either by mechanical or human means. The hopper, when full, is removed, usually by means of a locomotive but, occasionally, manually and, thereafter, a fresh, empty hopper is moved by the locomotive or manually to the working face and then filled with rock. The process continues in this way.

[0005] The empty hoppers and the filled hoppers are collected at one or more suitable locations, normally as close to the development end as possible, which have a sufficiently large marshalling area or turn-out for the hoppers. A train of filled hoppers is hauled by the locomotive to a discharge location at which the rock is further handled, processed or deposited, and empty hoppers are made available to be returned to the working face.

[0006] An object of the present invention is to provide a mucking system which allows for the clearing of rock, typically under conditions of the kind which have been described, in a faster and more cost-effective manner.

SUMMARY OF THE INVENTION

[0007] The invention provides a mucking system for use with a train which is movable along rail tracks on a ground surface, the train including a locomotive and a plurality of hoppers coupled to the locomotive, the mucking system including a self- levelling conveyor assembly and a support arrangement which is engaged with the conveyor assembly and which is actuable between a retracted position at which the support arrangement does not contact the ground surface and is engageable with the hoppers, whereby the support arrangement and the conveyor assembly are supported on the hoppers and are movable, in unison with the train, along the rail tracks, and an extended position at which the support arrangement is brought into contact with the ground surface and is disengaged from the hoppers, whereby support of the conveyor assembly is transferred from the hoppers via the support arrangement to the ground, thereby allowing the train to move along the rail tracks independently of the conveyor assembly and of the support arrangement.

[0008] Movement of the support arrangement to the extended position is effected while ensuring that the conveyor assembly is level and therefore operational.

[0009] The support arrangement can be of any appropriate kind and, in one form of the invention, includes a plurality of support legs which are actuable, preferably independently, to be extended into contact with the ground surface. Preferably, double-acting hydraulic cylinders are mounted internally within the support legs. The support arrangement may be controlled manually or by means of a programmable logic controller (PLC) or any other appropriate control device. Once the status of the support arrangement has been verified, in all relevant respects by the control device, the respective hydraulic cylinders are extended in a first stage, at whatever stroke is required, so that they contact the ground. The force exerted by each first stage hydraulic cylinder on the ground is sensed by means a pressure sensing proxy switch or any other appropriate mechanism. Once each first stage hydraulic cylinder contacts the floor, irrespective of any height variance therein, it is then locked in position. Subsequently, the control device is used to actuate the second stages of the hydraulic cylinders, in the respective legs, so that the legs are fully extended and the conveyor assembly is elevated off the hoppers to a self-levelled, raised position. The hoppers are then free to move along the rail track, independently of the conveyor assembly and of the support arrangement. It is then possible to load the conveyor belt at one end with rock which can be transported by the conveyor belt to an opposed, discharge end of the conveyor assembly at which the rock is discharged into successive hoppers, which are progressively moved forward by the locomotive, and at a controlled rate, relative to the discharge end.

[0010] With the support arrangement in the extended position an upper load- carrying surface of the conveyor is orientated to be level in a longitudinal direction and in a direction which is transverse to the longitudinal direction.

[0011] Mucking would not normally be carried out around a rail bend due to the characteristics of the conveyor belt. However, through the provision of a suitably located material transfer point, it would be possible to use the system to muck at, and hence effectively around, a bend.

[0012] The mucking system is movable when required on the rail tracks. Usually this movement would be predominantly in a straight line. However, through the use of an appropriate design, the system may be movable along a rail bend, identical to that traversed by the hoppers, with a radius of, say, in excess of 16m, and may accommodate vertical height variations on poorly laid or maintained rail tracks. These features are exemplary only and non-limiting.

[0013] Movement of the mucking system along a rail bend may be accomplished in any appropriate manner but, in one form of the invention, the conveyor assembly includes a plurality of modules which are interconnected at least during a mucking process, and which are then partially disconnected from one another when the conveyor assembly is to be moved. Each module preferably directly overlies, and is supported by, a respective hopper. [0014] When the modules are interconnected, a substantial degree of lateral and vertical adjustment can be effected, as appropriate, for example by means of hydraulically tensioned cables which run along the length of the conveyor assembly and locking pins, or similar devices which interconnect adjacent modules. The cables ensure that the conveyor assembly modules are correctly aligned, when the locking pins are in operative locations, and the modules are then pulled into position once lifted from the underlying hoppers by the support arrangement.

[0015] The invention further extends to a conveyor assembly which includes a looped conveyor belt, drive and return drums with which the looped conveyor belt is engaged, and a plurality of elongate beams which are longitudinally interconnectable, which carry troughing and return idlers to support the conveyor belt and which are adjustable, in a controlled manner, thereby to effect alignment of the beams in relation to each other, in horizontal and vertical planes, orientation of an upper load-carrying surface of the conveyor belt, and tracking of the conveyor belt relative to the beams.

[0016] As used herein the expression "drive and return drums" includes head and tail pulleys for the conveyor belt and any similar structure. Preferably a drive for the conveyor is via a motorised pulley at a discharge end of the conveyor.

[0017] The conveyor assembly may be provided in combination with a support arrangement which includes a plurality of extensible legs, lower ends of which project downwardly, in use, to respective locations displaced from the beams.

[0018] Longitudinally extending cables may be employed to align the beams. The cables may be tensioned through the use of hydraulic devices. [0019] Electrical power for operating the mucking system may be provided from any suitable source e.g. from a connection on the user's reticulation system, at or near the face or parked area. Use is made of electric motors which drive multiple hydraulic pumps fitted to each lifting module, together with hydraulic oil reservoirs and valves, each of which provides the hydraulic fluid flows required to operate the hydraulic cylinders fitted to that module. These hydraulics power packs are preferably integrally mounted on the beams of lifting modules.

[0020] The legs may extensible individually or simultaneously. The amount by which a leg is extended is dependent, at least, on the height of an adjacent ground surface e.g. a footwall on which a lower end of the leg is to rest. By controlling the force which each leg exerts on the footwall the amount by which each leg is extended, taking into account height variations in the foot wall, upper ends of the legs can be brought to desired positions so that, ultimately, an upper load-carrying surface of the conveyor belt is self-levelling and in a selected orientation, preferably horizontal.

[0021] The invention also provides a mucking module, for use with a hopper, which includes a conveyor beam which overlies the hopper, the conveyor beam and the hopper including interengageable formations whereby the conveyor beam can be supported on the hopper, the conveyor beam including idlers for supporting part of a load-carrying conveyor belt, a plurality of downwardly extending legs engaged with the conveyor beam, and wherein the legs are extensible into contact with ground adjacent the hopper thereby to elevate the conveyor beam and so allow the hopper to move independently of the conveyor beam. [0022] The plurality of downwardly extending legs may include at least first and second downwardly extending legs, on one side of the hopper, and at least third and fourth downwardly extending legs, on an opposing side of the hopper.

BRIEF DESCRIPTION OF THE DRAWINGS [0023] The invention is further described by way of example with reference to the accompanying drawings in which:

Figure 1 shows from one side a train of hoppers and a mucking system according to the invention in an operative condition i.e. with the mucking system supported on the ground in a raised position so that the train is movable relatively to the mucking system;

Figure 2 shows the mucking system from one side with the train removed;

Figure 3 shows the mucking system and the hopper train in a configuration in which as desired the mucking system can either be parked, or can be moved, with the mucking system free from the ground and engaged with the hoppers;

Figure 4 is a side view on an enlarged scale of part of the arrangement in Figure ; Figure 5, also on an enlarged scale, shows part of the arrangement in Figure 3; Figure 6 is similar to Figure 5 but illustrating a single mucking module, which comprises a single hopper and a single conveyor module, on an enlarged scale; Figure 7 is an end view of the mucking module, in the direction of an arrow "7" in Figure 6;

Figure 8 is a perspective view of the mucking module in Figure 6; and

Figure 9 is similar to Figure 8 but wherein support legs have been extended to support a conveyor module on the ground adjacent the hopper, i.e. corresponding to the operating configuration shown in Figure 1. DESCRIPTION OF PREFERRED EMBODIMENT

[0024] Figure 1 of the accompanying drawings illustrates a portion of a tunnel 10 in an underground excavation which extends from a remote end 12 to a working end 14. At the working end a rock face 16 is blasted using conventional techniques in order to develop the tunnel in a desired direction. A loader 20 is positioned at the rock face 16. The loader is used after drilling and blasting have taken place at the rock face.

[0025] As the tunnel is extended a rail line is constructed. The rail line consists of parallel tracks 22 which are placed on sleepers 24 which rest on a ground surface 26.

[0026] The clearing of rock from the development end 16 of the tunnel is accomplished using a mucking system 30 in combination with a train 32.

[0027] The train 32 comprises a plurality of conventional hoppers 36 which are connected to one another using suitable couplings 38 and which are positioned to run on the tracks 22. A leading hopper is designated 36A. A locomotive (not shown) is coupled to the hoppers in a conventional manner, at the left end in Figure 1 , and is used to haul the hoppers to and fro along the tracks as required.

[0028] The mucking system 30 includes a conveyor assembly 40 and a support arrangement 42, (Figures 4 to 9). The conveyor assembly 40 includes a conveyor with an endless looped belt 44, (shown in dotted outline in Figures 4 and 5) which passes over a drive drum 46 and a return drum 50 (see Figure 2). The drive drum 46 is actuable via a motorised pulley at a discharge end of the conveyor belt. [0029] A feed bin 54 is positioned near the loader 20 for directing material onto the conveyor belt. The bin is configured to take "over the back" discharge from the loader 20, which is tracked (see Figure 2). The bin can, however, be altered to accommodate any loader. [0030] The conveyor belt is supported on a plurality of articulated conveyor modules. The modules are of two types designated 60A and 60B respectively. These modules alternate along the length of the conveyor assembly.

[0031] Each module 60A includes an elongate beam 62A (Figures 7, 8 and 9) which carries a supporting framework 64 (Figure 7) to which are mounted a combination of troughing and return idlers 68 for the conveyor belt, in both directions of movement. Additionally, impact idlers (not shown) are located below the feed bin 54. The module 60A has two transversely extending support members 72 and 74 (Figure 8), located near respective opposing ends of the beam 62A. Four downwardly extending legs 76, 78, 80 and 82 respectively (Figures 2, 3, 4, 8 and 9) are fixed to respective ends of the support members. The legs 76 and 82 are on one side of the hopper, and the legs 78 and 80 are on an opposing side of the hopper. Each leg has a telescopic, tubular construction and, internally, includes two double-acting, hydraulically actuated, piston and cylinder assemblies. A first stage cylinder is connected, at a lower end, via a pressure sensing proxy switch fitted internally within a ball joint (not shown), to a respective load-bearing foot 84.

[0032] When the legs are elevated, as is shown from one side and one end in Figures 6 and 7 respectively, a lower surface of the beam 62A rests on, and is engaged with, an opposing upper surface of an underlying hopper 36. This interengagement is facilitated by the provision of suitable complementary formations 85 on the beam and on the hopper only notionally shown in Figures 6 and 7. These formations ensure that the beam is restrained against longitudinal movement 86 and transverse movement 88 relative to the hopper.

[0033] Figure 8 shows an end of the beam 62A in a module 60A. The beam includes spaced upwardly extending spigots 90 and 92 respectively. Similar spigots are provided at a remote end of the beam.

[0034] A module 60B has a number of aspects which are substantially the same as for a module 60A. These similar aspects are not further described. However a module 60B does not include transversely extending support members 72 and 74, nor any of the legs 76 to 82. Formations on an underside of the beam 62B, which engage with an underlying hopper, extend downwardly to a greater extent than the corresponding formations on a beam 62A. Opposed ends of the beam 62B include projections which carry respective spigots 94 and 96, see Figure 8, which are directly engaged with the locking pins 90 and 92, when a beam 62A is horizontally aligned with a beam 62B.

[0035] The transverse beams 72 and 74, and the legs 76 to 82, make up part of the support arrangement 42 for the conveyor assembly.

[0036] At the development end 14 rock, after drilling and blasting, is fragmented and loosened during a working shift. A train of hoppers 36 is then moved by the locomotive along the tracks 22 with the loader 20 coupled to the leading car 36A. This is done with the conveyor assembly in the movement mode shown in Figures 3 and 5. Along the length of the train the legs 76 to 82 are elevated and are clear of the ground surface 24. The full weight of the conveyor assembly 30 and of the support arrangement 42 is transferred via the beams to the hoppers. The conveyor assembly and support arrangement are thus movable along the rail track in unison with the train.

[0037] With the train halted at a chosen location, the respective legs 76 to 82 are lowered, along the length of the conveyor assembly, so that each leg, at a lower end, is brought into contact with the ground surface 24 adjacent the track. The first stage of the leg is then locked into position. The legs extend downwardly from opposed ends of the respective members 72 and 74. As the legs are displaced laterally, relative to the hoppers, see for example Figure 9, the legs are clear from outer extremities of the hoppers. [0038] Each leg includes two double-acting hydraulic cylinders, mounted internally within the leg, which can be extended or retracted in a sequenced, two-stage process. Actuation of the cylinders can be done manually, but preferably is controlled and sequenced by means of a control device such as a PLC (not shown). The control device also constantly monitors the functionality of the system. When required the control device causes each of the hydraulic legs to be extended, in the first stage, through whatever stroke is required, until the respective feet 84 contact the ground. The process is controlled by means of a respective pressure sensing valve or equivalent device, located within the ball joint at the bottom of each leg, which senses the force being exerted by the hydraulic cylinders on the ground. When this force reaches a predetermined level, the extension of the first stage leg is ceased. The legs, in respect of the first stages, are then locked in position. Subsequently, the control device causes a main cylinder in each leg to extend so that the transverse members 72 and 74, and thus each module 60A, are elevated. [0039] As the modules 60A are lifted the beams 62A are elevated. The respective spigots 90 and 92, at opposed ends of the beams, are brought into locking engagement with the respective adjacent corresponding locking pins 94 and 96 on the beams 62B. The beams 62A are thereby locked to the beams 62B. The engagement of the spigots with the locking pins causes the beams to align longitudinally (viewed in plan). As the modules 60A are further lifted (by extending the various support legs) the modules 60B are also lifted. Each module 60B is, at this stage, suspended between a pair of adjacent modules 60A which, in turn, are supported on the respective support legs 72 to 82. [0040] In a subsequent step the control device functions to level the beams in a horizontal sense. Each stage of each leg can be individually extended or retracted, as required, to ensure that the elongate beams 62A and 62B, alternating through the conveyor assembly, are levelled. The conveyor belt is automatically levelled in the process. [0041] In order for the aforementioned relative movement to take place the tension in the conveyor belt is reduced substantially. This allows the modules to take up the alternating higher and lower positions shown in Figure 5 with the belt still engaged with the conveyor assembly.

[0042] When the modules are interconnected, a substantial degree of lateral and vertical adjustment can be effected, as appropriate, by means of hydraulically tensioned cables 98 (notionally shown only in Figure 7) which run along the length of the conveyor assembly. The cables ensure that the conveyor assembly modules are correctly aligned and are pulled into position once lifted from the underlying hoppers by the support arrangement. [0043] By adjusting the degree of extension of each leg the beams can be levelled in a longitudinal direction, or in a transverse direction. If, viewed in plan, the beams are not correctly linearly aligned the cables 98 are tensioned, or released, in order to achieve linear alignment of the beams. Such alignment is important to ensure that the conveyor belt tracks properly, over the idlers.

[0044] Once the beams have been interconnected and levelled the tension in the belt is restored hydraulically so that it is in an operative mode.

[0045] The feed bin 54 is supported on components of the support arrangement which are adjacent the working face i.e. at an extremity of the support arrangement. Front, side and back plates of the feed bin, a shock absorber for the feed bin, and a conveyor tail pulley, are integral within the feed bin construction which is locked in position by means of pins so that the feed bin is maintained in an operative mode.

[0046] The drive pulley 46 is then operated to drive the conveyor belt in a conventional manner. An upper load-bearing surface 100 of the conveyor belt is moved in a direction away from the loading end 14 towards the locomotive which, in turn, is driven at a creep speed so that materials falling from the discharge end 2 of the conveyor belt, at the drive drum 46, fall directly into an underlying hopper. The speed of the locomotive is controlled to ensure that the hopper adjacent the discharge end, which initially is the hopper adjacent the locomotive, is filled evenly with rock.

[0047] An optional chute automatically senses a junction between two cars and moves, as the train moves, to deflect falling rock from a leading car into a following car, so that the rock does not fall through a gap which exists between adjacent cars. [0048] The loading process continues in this way. Rock at the working end 14 is continuously loaded using the loader 20 via the feed bin 54 onto the load-carrying surface 00 of the conveyor belt and, at the other end of the conveyor belt, the rock is discharged continuously, into the hoppers 36, in succession.

[0049] Once all the hoppers are loaded the conveyor belt is stopped. The loaded hoppers can then be moved along the track to a discharge location at which the rock from each hopper is discharged for further handling or processing.

[0050] In order to move the mucking system away from the now cleared development end, the aforementioned sequence of operating steps is reversed. Thus, initially, the support legs are retracted to lower the beams 62A and 62B so that the beams engage with, and rest on, upper ends of the hoppers along the length of the conveyor assembly. The weight of the conveyor assembly and of the support arrangement is thereby transferred fully onto the hoppers.

[0051] The locking pins are disengaged from the modules and the feed bin. The loader is coupled via a tow bar to the hopper 36A.

[0052] The train, towing the loader and carrying the complete mucking system, (all now in the Figure 3 mode) can then move freely along the track to a safe or alternative location so that, at the development end, blasting can take place.

[0053] Once the blasting process has been completed the train, the conveyor assembly and the support arrangement, are moved along the track and are returned to the position shown in Figure 1. The aforementioned sequence of operating steps is repeated in that the weight of the conveyor assembly is transferred from the cars to the legs and, with the conveyor assembly disengaged from the cars, it is possible for the loading process to recommence.

[0054] The mucking system of the invention thus relies on the repeated attachment of the conveyor assembly to the train and subsequent detachment of the conveyor assembly from the train, so that the conveyor assembly can be moved between an operative position (Figure 1 ) at which rock can be loaded onto the train and a remote position at which work at the development end of the tunnel can take place without the likelihood of damage being caused to the conveyor assembly. Additionally, there is no likelihood that the conveyor system will impede the free movement by rail of items required to equip the recently excavated tunnel, such as rails, sleepers, ventilation ducting, electrical cables, air and water hoses and so on, and the drilling machines, explosives and accessories which are necessary for the further development of the tunnel.

[0055] The system of the invention allows for:

(a) a reduction in the number, and hence cost, of cross-cuts or marshalling areas, which may currently be required to enable the hoppers to be stored near to the tunnel development end, as the tunnel is extended;

(b) a reduction in the number and cost of hoppers and locomotive movements required. This results in a faster cleaning of the development end and in a safer operating environment;

(c) a considerably faster, and more controlled, hopper loading method which allows a complete hopper to be filled more evenly as it is passed under the conveyor discharge end than what could be achieved, for example, by rocker shovel loading from an end of the hopper; and

(d) faster development with a reduction in labour. [0054] With the mucking system the hoppers, to the capacity of the locomotive, are filled more or less in a continuous operation with rock. The tedious high cost process of creating marshalling areas and shunting single hoppers, in turn, to the working end is avoided. Safety is enhanced by fewer hopper and locomotive movements. Substantial savings in time and cost are obtained which imply that the development of the tunnel takes place in a safer and in a more rapid and cost-effective manner.

Claims

1. A mucking system for use with a train which is movable along rail tracks on a ground surface, the train including a locomotive and a plurality of hoppers coupled to the locomotive, the mucking system including a conveyor assembly and a support arrangement which is engaged with the conveyor assembly and which is actuable between a retracted position at which the support arrangement does not contact the ground surface and is engageable with the hoppers, whereby the support arrangement and the conveyor assembly are supported on the hoppers and are movable, in unison with the train, along the rail tracks, and an extended position at which the support arrangement is brought into contact with the ground surface and is disengaged from the hoppers, whereby support of the conveyor assembly is transferred from the hoppers via the support arrangement to the ground, thereby allowing the train to move along the rail tracks independently of the conveyor assembly and of the support arrangement.

2. A mucking system according to claim 1 wherein, once the support arrangement has been actuated to the extended position, the conveyor assembly is level and operational.

3. A mucking system according to claim 1 wherein the support arrangement includes a plurality of support legs which are actuable to be extended into contact with the ground surface.

4. A mucking system according to claim 3 wherein each support leg includes two double-acting hydraulic cylinders, wherein a first stage cylinder is extendible until the cylinder is locked by sufficient contact with the ground, and a second stage cylinder then acts to elevate the conveyor assembly off the hoppers to a levelled position.

A conveyor assembly which includes a looped conveyor belt, drive and return drums with which the looped conveyor belt is engaged, and a plurality of elongate beams which are longitudinally interconnectable, which carry troughing and return idlers to support the conveyor belt and which are adjustable, in a controlled manner, thereby to effect alignment of the beams in relation to each other, in horizontal and vertical planes, orientation of an upper load-carrying surface of the conveyor belt, and tracking of the conveyor belt relative to the beams.

A conveyor assembly according to claim 5 in combination with a support arrangement which includes a plurality of extensible legs, lower ends of which project downwardly, in use, to respective locations displaced from the beams.

A conveyor assembly according to claim 6 which includes hydraulically tensionable cables which are operable to assist in effecting alignment of the beams.

A mucking module, for use with a hopper, which includes a conveyor beam which overlies the hopper, the conveyor beam including formations whereby the conveyor beam can be supported on the hopper and idlers for supporting part of a load-carrying conveyor belt, and a plurality of downwardly extending legs engaged with the conveyor beam, and wherein the legs are extensible into contact with ground adjacent the hopper thereby to elevate the conveyor beam and so allow the hopper to move independently of the conveyor beam.

9. A mucking module according to claim 8 wherein each leg is extensible in a first stage into ground contact and then in a second stage to elevate the conveyor beam.

10. A mucking system according to claim 9 wherein the leg is locked in the first stage, in contact with the ground, before extension in the second stage takes place.