Patent Publication Number: US-2021164349-A1

Title: Recovering conveyor systems and continuous miners from mined plunge tunnels in underground mines

Description:
TECHNICAL FIELD 
     The present invention generally relates to a system for recovering a continuous miner arrangement from a tunnel. The present invention has particular, although not exclusive application to underground coal mining. 
     BACKGROUND 
     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. 
     Underground coal mining traditionally involves the formation of series of roadways (i.e. mined out tunnels) of varying layout to suit the reserve of coal being mined. Roadways are supported, in the roof strata and/or the side-walls (called ribs), to enable the safe passage of personnel to enter and exit the mine. The supported roadways also stay safely open for the passage of equipment, the installation of services (compressed air, water, electrical power infrastructure), and the carriage of mine ventilation air throughout the mine. 
     A series of unmined coal ‘blocks’ (or unmined coal reserve areas) are located between the roadways, and the roadways provide access to these unmined coal blocks. A series of conveyors transport the coal mined from the blocks away from the mining areas and to the surface of the mine. 
     AU 2016210621 discloses a system in which a continuous miner forms dead end plunge cuts from gate roads to mine the blocks. The miner is coupled to a flexible conveyor system, including serial conveyor modules, which carries the coal away from the continuous miner to fixed conveyors elsewhere in the mine. The flexible conveyor system can continuously transport coal either in a straight line or around corners owing to its flexibility. 
     There are varying types and styles of flexible conveyor systems, but they all have the features of enabling the continuous transport of coal along their length. The flexible conveyor systems comprise a number of inter-connected module sections of varying length and connectivity, and are of a form that can flexibly transport coal around varying-angled corners of the connected roadways in the areas of the underground mine plan layout. The flexible conveyor systems extend to the active mining face where the coal is being mined by the continuous miner. 
     There are many circumstances where the continuous miner and/or the flexible conveying system is unable to move under their own normal traction devices to extricate the equipment out of the partially or fully mined plunge tunnels. Such circumstances, which would give rise to the need for the recovery of equipment from the partially or a fully mined plunge, are as follows:
     From a rock strata failure in the roof—i.e. from a ‘Roof fall’ where rock from the roof of the plunge cut falls onto the continuous miner or the flexible conveying system such that it cannot move itself out of the plunge under its normal powered traction systems;   From a rock strata failure in the side wall of the plunge—i.e. from a ‘Rib fall’ where rock from the sidewall (or ‘Rib’) of the plunge falls onto the continuous miner or the conveying system such that it cannot move itself out of the plunge under its normal powered traction systems;   From an electrical power failure to the continuous miner and/or to the conveying system which could be caused, for example, from a power ‘trip’ in a circuit breaker or damage to a power cable—there are other causes that could be cited; and   From an event that causes a hydraulic system failure or leak under various circumstances.   

     The preferred embodiment provides a system for recovering a continuous miner arrangement under such circumstances. 
     SUMMARY OF THE INVENTION 
     According to one aspect of the present invention, there is provided a system for recovering a continuous miner arrangement from a tunnel, the system including:
         a coupler for coupling the continuous miner arrangement to a pulling apparatus; and   the pulling apparatus for pulling the continuous miner arrangement from the tunnel.       

     Advantageously, the pulling apparatus may pull the continuous miner arrangement from the tunnel, either fully or partially until the continuous miner arrangement may once again retract from the tunnel under its own power. 
     The system may further include one or more guides for guiding the continuous miner arrangement being pulled. The guides may include rollers. 
     The pulling apparatus may include a winch with a line terminating in the coupler. The pulling apparatus may be fixed or static. 
     The system may further include a support assembly for supporting the pulling apparatus. The support assembly may include a pair of lateral supports located on either side of the tunnel. Each lateral support may extend across a gate road from which the tunnel extends. Each lateral support may be triangular. The support assembly may further include a base support located opposite the tunnel. 
     The pulling apparatus may include at least one ram. The ram may be coupled with the coupler to the centre of the continuous miner arrangement. Alternatively, the at least one ram may include a pair of rams for mounting to either side of the continuous miner arrangement. The ram may be a hydraulic ram. 
     The continuous miner arrangement may include a continuous miner and a flexible conveyor system coupled to the continuous miner. 
     According to another aspect of the present invention, there is provided a method for recovering a continuous miner arrangement from a tunnel, the method involving:
         coupling the continuous miner arrangement to a pulling apparatus; and   pulling the continuous miner arrangement from the tunnel with the pulling apparatus.       

     The method may involve providing guides to guide the continuous miner arrangement along a path. 
     The method may involve decoupling one or more conveyor modules from the continuous miner arrangement, prior to pulling. The method may involve pulling and then removing the rearmost conveyor of the continuous miner arrangement, before repeating so that the continuous miner arrangement is serially removed. 
     The method may involve assembling a support assembly for supporting the pulling apparatus. 
     According to another aspect of the present invention, there is provided a system for recovering a mining equipment from a tunnel, the system including:
         a coupler for coupling the mining equipment to a pulling apparatus; and   the pulling apparatus for pulling the mining equipment from the tunnel.       

     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. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       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 the Invention in any way. The Detailed Description will make reference to a number of drawings as follows: 
         FIG. 1  is a schematic plan view of a guided pathway recovery system for recovering a continuous miner arrangement in accordance with a first embodiment of the present invention; 
         FIG. 2  is a schematic plan view of a hydraulic extraction recovery system for recovering a continuous miner arrangement in accordance with a second embodiment of the present invention; and 
         FIG. 3  is a schematic plan view of another hydraulic extraction recovery system for recovering a continuous miner arrangement in accordance with a third embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     According to a first embodiment of the present invention, there is provided a guided pathway recovery system  100  shown in  FIG. 1  for recovering a continuous miner arrangement  102  from a dead-end plunge tunnel  104  which it is forming. The continuous miner arrangement  102  includes an unmanned continuous miner  106  and a flexible conveyor system  108  coupled to the continuous miner  106 . 
     The system  100  also includes a gate road  110  from which the plunge tunnel  104  is formed. A static conveyor  112  is located in the plunge tunnel  104  and can be loaded with coal from the flexible conveyor system  108  using a bridge  113 . Coal is then unloaded at the terminus  114 . 
     The system  100  includes a mechanical coupler  116 , including a hook or shackle for example, for coupling the continuous miner arrangement to a pulling apparatus  118 . The pulling apparatus  118  pulls the stuck continuous miner arrangement  102  from the tunnel  104 . 
     Advantageously, the pulling apparatus  118  can pull and extricate the continuous miner arrangement  102  from the tunnel  104 , either fully or partially until the continuous miner arrangement  102  can once again retract from the tunnel  104  under its own power. 
     The system  100  further includes opposed guides  120   a,    120   b  for guiding the continuous miner arrangement  102  being pulled. Each guide  120  includes a truss support assembly  122 , and a series of rollers  124  against which the arrangement  102  can engage during pulling. 
     The pulling apparatus  118  typically includes a winch with a line  126  terminating in the coupler. The pulling apparatus  118  forcibly pulls the conveyor equipment  108  and the continuous miner  106  backwards to withdraw it from the mined plunge tunnel  104 . 
     In the circumstance where the continuous miner arrangement  102  cannot withdraw for reasons unrelated to the arrangement  102  being ‘blocked’ in the plunge tunnel  104 , then the force required to withdraw the arrangement  102  is much less than where the equipment is ‘blocked’. Such forces in this circumstance need only be capable of moving the arrangement  102  itself and overcoming its inertia of motion and the rolling or skidding resistance that would apply. 
     The recovery system  100  deploys a series of structures and ‘guides’  120  which control the path that the withdrawing conveyor  108  and continuous miner  106  travel through, and a cable  126  and pulling force that ‘pull’ the equipment out of the mined plunge tunnel  104  until the equipment is fully withdrawn. In this case, the conveyor system  108  or other equipment need not be disconnected in order to recover the arrangement  102 —it is simply ‘pulled’ out of the plunge tunnel  104  and the ‘guide’ structures  120  ensure that the arrangement  102  travels through the desired travel path that it needs to travel through in order to be fully back into the roadway  110  of the underground mine. 
     A Guided Pathway Recovery method for recovering the continuous miner arrangement  102  is now briefly described. 
     Where the arrangement  102  is not ‘blocked’ in the mined plunge tunnel  104 , but rather it cannot operate due to some electical power of other systems failure (i.e. hydraulic or communications etc), the opposed guides  120   a,    120   b  are installed. A series of support structures  122  are moved into place and erected or assembled to form an integrated series of structures  122  on either side of the roadway in the vacinity of the plunge tunnel  104  where the arrangement  102  cannot withdraw by its normal operating capability. 
     The structures  122  are ‘pinned’ or engaged into the ground or the sidewalls of the roadway  110  by ground or rock bolting practices, such that the structures  122  cannot be moved and are rigidly fixed in position. 
     A series of rollers or rotating wheels  124 , or low surface friction fixed materials, are installed into the assembled/erected structures  122 . The rollers  124  allow the side rails of the arrangement  102  to move past the fixed structures  122  and cause the arrangement  102  to follow a pre-designated travel pathway by virtue of the configuration of the assembled structures  122 . 
     The attachment of the coupler  116  to the end of the last conveyor module enables the pulling apparatus  118  to apply a pulling force to the cable  126 . The pulling apparatus  118  can include a winching device (suitably fixed in position in order to apply the force required) or it could include a large item of undergound mining equipment with suitable motive pulling force (i.e. a tracked dozer or a large rubber tyred loader). 
     The pulling apparatus  118  pulls the arrangement  102  out of the plunge tunnel  104  through the use of the cable  126  whereby the whole arrangement  102  travels through the pre-designated travel pathway to exit the plunge tunnel  104 . 
     According to a second embodiment of the present invention, there is provided a hydraulic extraction recovery system  200  shown in  FIG. 2 . The system  200  is used in the circumstances where the continuous miner arrangement  102  cannot withdraw because it is either partially or wholly ‘blocked’ in the plunge tunnel  104  because there has been a ‘roof’ fall event or a sidewall ‘rib’ failure event, then the loads required to withdraw the equipment are appreciably larger. This increased load is due to the need to forcably ‘pull’ the arrangement  102  through, around, under or over the rock strata that has failed and which is consuming some of the plunge tunnel space and ‘blocking’ the equipment from moving. 
     The pulling apparatus  202  includes at least one hydraulic ram which is coupled with the coupler  204  to the centre of the continuous miner arrangement  102 . The system  200  includes a support assembly  206  for supporting the pulling apparatus  202 . The support assembly  206  includes a pair of triangular lateral supports  208   a,    208   b  located on either side of the plunge tunnel  104 . Each lateral support  208  extends across and fills the gate road  110  from which the plunge tunnel  102  extends. The support assembly  206  further includes a base support  210  located opposite the tunnel. 
     The support assembly  206  includes a connected series of structural members (i.e. steel beams and props/supports). The recovery method involves serially disconnecting each successive conveyor module (or segment) along the length of the conveyor  108  from the rear of the continuous miner arrangement  102 . The ram applies the hydraulic force through one or more connecting points along the length of each individual conveyor unit (or segment)—unit the arrangement  102  is ‘free’ of the blockage which is preventing it from being withdrawn, or until all of the arrangement  102  is removed from the mined plunge tunnel  102 . 
     A hydraulic extraction recovery method is now briefly described, where the arrangement  102  in the plunge tunnel  104  is ‘blocked’ from moving at all owing to some form of strata failure event (either ‘roof’ or sidewall ‘rib’). Any conveyor modules in the roadway  110  are first decoupled and removed. 
     A large specially configured ‘load spreading beam’  210  is installed on the opposite side of the roadway  110  from that of the entry to the plunge tunnel  104  where the arrangement  102  is ‘stuck’. The installation of the beam  210  is such that it is specifically positioned in order that a hydraulic ‘pulling’ force can be applied longitudinally and parallel along the centre-line axis of the plunge tunnel  104  where the arrangement  102  is ‘stuck’. 
     Next, installation of the lateral supports  208  is undertaken including associated specially configured series of supporting props/members and other associated supporting structures in and across the roadway  110 . The supports  208  extend to the opposite side of the roadway  110  from the large load spreading beam  210  in order to provide a suitable network of ‘bracing’ structures against which the forces can be sustained in order to forcibly withdraw the arrangement  102  from the plunge tunnel  104 . 
     The load spreading beam  210  and the supporting braces/structures are fixed in place using ground or rock bolting techniques. 
     The hydraulic ram  202  is attached to the load spreading beam  210  and is also connected to a suitable sized hydraulic power pack, for the purposes of applying a pulling force to the arrangement  102  ‘stuck’ in the plunge tunnel  104 . 
     By connecting the hydraulic ram  202  to designated attachment points on each conveyor unit/segment along the length of the conveyor system (by the use of a suitable coupler  204  including cables, chains, wire, ropes  126 ), and by operating the hydraulic ram  202  through its designated travel distance, the ram can be cycled in and out with each cycle applying a ‘pulling force’ on the arrangement  102  such that the arrangement  102  is partially withdrawn from the plunge tunnel with each hydraulic stroke, and between each cycle the ram being connected to the next attachment point such that with each cycle the whole length of the arrangement  102  is withdrawn from the plunge tunnel  104 . 
     When each rear conveyor unit/segment has exited the plunge tunnel  104 , the unit is decoupled and relocated/moved away from the recovery work area at the mouth of the plunge tunnel  104  and the next rear conveyor unit/segment is connected to the hydraulic ram  202  in order for that next successive unit/segment to be pulled and withdrawn from the plunge tunnel  104 . 
     The foregoing process continues until all of the arrangement  102  has been withdrawn from the plunge tunnel  104 . The recovery system  200  is then removed once the arrangement  102  has been withdrawn and the mining system operated as per normal. 
       FIG. 3  shows an alternative configuration where a pair of rams  202  are mounted to either side of the continuous miner arrangement  102  for increased pulling force. 
     A person skilled in the art will appreciate that many embodiments and variations can be made without departing from the ambit of the present invention. 
     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. 
     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.