Our Ref: 34900103/AJS/Ijr P/00/011 Regulation 3:2 AUSTRALIA Patents Act 1990 ORIGINAL COMPLETE SPECIFICATION INNOVATION PATENT Applicant: M.L.C. & Co Pty Ltd trading as C&C Building Contractors c/- Davies Collison Cave, Level 10, 301 Coronation Drive, Milton, Queensland 4064 Address for Service: DAVIES COLLISON CAVE Patent & Trade Mark Attorneys Level 10, 301 Coronation Drive Milton QLD 4064 Invention Title: "Tunnel lining method" The following statement is a full description of this invention, including the best method of performing it known to me:- TUNNEL LINING METHOD Background of the Invention 100011 The present invention relates to an apparatus and method for lining a tunnel, and in one particular example, for lining a tunnel in an underground coal mine by dispensing a material, such as a concrete product, onto a tunnel surface, as well as to a method of supporting a tunnel. Description of the Prior Art [0002] The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that the prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates. [00031 Currently underground coal mines utilise bolt and meshing techniques for supporting tunnel side walls and roofs, for example as part of heading or roadway developments. The installation process for such bolt and mesh arrangements typically involves mining the tunnel and installing preliminary bolts, followed by a second stage in which additional bolts and the retaining mesh are installed. [00041 An example of this process will now be described with reference to Figures IA and 1B. [00051 In this example, during a first pass, a continuous miner 100 or other similar mining machine, mines a heading to create a tunnel 110, and uses a bolting rig 101 to install retaining bolts I11 and a mesh 112 in the tunnel walls and roof. The bolts 111 are typically nylon bolts, which act to provide primary support, whilst the mesh 112, acts to provide support for the strata between the bolts 111. The bolts and mesh are installed in accordance with requirements defined by a geotechnical engineer, as will be appreciated by persons skilled in the art.
-2 10006] Following installation of the primary support, the heading is inspected by the mine site geotechnical engineer and a secondary support is defined and installed. To achieve this, as shown in Figure 1 B, a cable bolting machine 120 having cable pusher and grout pump is used to insert and grout cable bolts 113 into place. The cable bolts can extend long distances into the strata and often require grouting to ensure the cable bolts are secured within the strata. [0007] There is significant cost involved with the installation of bolts into the strata as a form of primary and secondary support. Additionally, headings and roadways developed in this manner also require stone dusting to reduce the explosive environment created with the presence of large amounts of airborne coal dust. Accordingly an alternative technique for providing tunnel support is required. [0008] Whilst application of fibre reinforced concrete (fibrecrete) via shotcrete rigs is known, there has been limited use of this process in coal mining due to the fact that shoterete rigs cannot be used within Explosive Risk Zone (ERZ) Areas of coal mines. Summary of the Present Invention [00091 In one broad form the present invention seeks to provide a method of providing a tunnel support in an underground coal mine, the method including dispensing material from a spray nozzle of a vehicle onto a surface of the tunnel to thereby support the tunnel. [0010] Typically the method includes providing bolts in at least one of the tunnel walls and roof before dispensing the material. [00111 Typically the material is at least one of: a) a concrete product; and, b) fibrecrete. [00121 Typically the method includes dispensing material to form. a material layer over at least part of the tunnel surface. [0013] Typically the method includes dispensing material so that the layer has a respective thickness on different parts of the tunnel surface.
-3 10014] Typically the method is performed using a vehicle having: a) a chassis; b) a plurality of wheels or tracks c) a flameproof engine for driving the wheels or tracks via a drive train; d) a material dispensing system including: i) a hopper that contains the material in use; ii) a movable boom; iii) at least one spray nozzle supported by the boom; iv) one or more pipes for coupling the spray nozzle to the hopper; and, v) a pumping system for pumping material from the hopper to the spray nozzles, thereby dispensing material from the spray nozzles onto a surface of the tunnel, [0015] In another broad form the present invention seeks to provide a method of lining a tunnel in an underground coal mine, the method including dispensing material from a spray nozzle of a vehicle onto a surface of the tunnel. [00161 In another broad form the present invention seeks to provide an apparatus for lining a tunnel, the apparatus including a vehicle having: a) a chassis; b) a plurality of wheels or tracks c) a flameproof engine for driving the wheels or tracks via a drive train; d) a material dispensing system including: i) a hopper that contains the material in use; ii) a movable boom; iii) at least one spray nozzle supported by the boom; iv) one or more pipes for coupling the spray nozzle to the hopper; and, v) a pumping system for pumping material from the hopper to the spray nozzles, thereby dispensing material from the spray nozzles onto a surface of the tunnel. [00171 Typically the vehicle includes: a) a sensor; and, -4 b) a controller coupled to the sensor, the controller being adapted to receive signals from the sensor and selectively deactivate the engine depending on the received signals. [00181 Typically the sensor is at least one of: a) a gas sensor that senses gas levels, the controller selectively deactivating the engine in the event that gas levels exceed a predefined gas level; and, b) a temperature sensor that senses a temperature, the controller selectively deactivating the engine in the event that temperature exceed a predefined temperature. [0019] Typically the engine provides power to the pumping system for pumping the material. [00201 Typically the vehicle includes an electrical system suitable for use in an underground coal mine ERZ area. [0021] Typically the vehicle is at least one of: a) usable in or certified for use in an explosive risk zone; and, b) usable in or certified for use in an underground coal mine. Brief Description of the Drawings [0022] An example of the present invention will now be described with reference to the accompanying drawings, in which: [00231 Figure 1A and 1B are schematic end views of a prior art tunnel supporting process; [0024] Figure 2 is a schematic diagram of an example of an apparatus for use in lining a tunnel; [0025) Figure 3A and 3B are schematic end views of a tunnel supporting process; and, [0026] Figures 4A to 4D are photographs of a specific example of an apparatus for lining a tunnel. Detailed Description of the Preferred Embodiments [0027] An example apparatus for dispensing material to provide a tunnel lining will now be described with reference to Figure 2.
-5 [00281 In this example, the apparatus is in the fon of a vehicle 200 having a chassis 210, a number of wheels 211 (although tracks could alternatively be used) and a flameproof engine 220 for driving the wheels 211 via a drive train. A material dispensing system is also provided, the dispensing system including a hopper 231 that contains the material in use, a movable boom 232, at least one spray nozzle 233 supported by the boom 232. One or more pipes and/or hoses 234 are provided for coupling the spray nozzle 233 to the hopper 231, with a pumping system 235 operating to pump material from the hopper 231 to the spray nozzles 233, thereby dispensing material from the spray nozzles, [00291 The vehicle will also typically include other features, including a frame 212, body work, an engine cover, cab or the like, as well as operational controls, such as steering joysticks, an accelerator / brake or the like. [0030] In one example, the vehicle 200 is used to dispense a concrete product, such as fibrecrete, onto a surface of a tunnel in an underground coal mine to thereby form a lining that acts as a tunnel support. In this regard, the vehicle is provided with a flameproof engine, allowing the vehicle to be used in ERZs, in turn allowing the vehicle to enter and dispense the fibrecrete or other similar materials within coal mines, which has not previously been possible in this mobile forn. [00311 An example process for supporting a tunnel by lining a tunnel surface using the apparatus of Figure 2 will now be described with reference to Figures 3A and 3B. [0032] In this example, during a first pass, a continuous miner 300 or other similar mining machine, mines a heading to create a tunnel 310, and uses a bolting rig 301 to install retaining bolts 311 in the tunnel walls and roof. The bolts 311 are typically nylon bolts, which act to provide primary support. It will be noted however that unlike traditional techniques described above with respect to Figures 1A and lB, a mesh is not necessarily required. [00331 Following installation of the primary support, the heading is inspected by the mine site geotechnical engineer before the vehicle 200 applies a layer of concrete material 312 to the tunnel walls and roof, to thereby form a lining (having a nominated thickness) over at least the tunnels walls and roof.
-6 [0034] The concrete material is applied at high velocity so that the concrete material adheres to the tunnel surface, and infiltrates fissures in the tunnel surface, thereby mechanically coupling the concrete lining layer to the tunnel surface and enhancing the support provided. As part of this process, the layer can also be provided with a respective thickness on different parts of the tunnel surface, thereby varying the degree of support provided. [00351 During this process, secondary bolts 313 may also be inserted into the walls and roof, although this is not essential and may depend on a condition of the tunnel, the types of strata through which the, tunnel passes, or the like. However, it will be noted that the secondary bolts 313 are shorter than the primary bolts 311 and the cable bolts 113 used in the prior art techniques, making them easier to install, as will be appreciated by persons skilled in the art. [0036] Accordingly, the above described vehicle 200 can be used in order to apply concrete materials to surfaces in tunnels of underground coal mines, to thereby establish a tunnel lining, which in turn acts as part of a tunnel support. [0037] The use of fibrecrete, or other similar materials, to provide a tunnel support in an underground coal mine can provide a number of benefits over typical tunnel support techniques. [0038] For example, the fibrecrete layer seals the tunnel surface, and hence the coal strata. This reduces air borne coal dust and gas migration as well as preventing the coal and strata from fretting, as well as reducing the need for stone dusting. The concrete materials typically provide a smooth surface, which allows for enhanced ventilation performance as the fibrecrete produces a smoother envelope with less drag. [0039] The fibrecrete can provide structural support, which reduces or eliminates the need for meshing as the fibrecrete layer (in combination with bolts) provides the required strata support. This reduces the time required to install support by avoiding the need for mesh and also reducing bolting requirements. [0040] The use of the above method and apparatus can allow for enhanced safety by reducing manual handling of mesh. Furthermore, the apparatus can be provided as an autonomous vehicle allowing for automated application of the tunnel lining, thereby reducing worker exposure to hazards. [0041] Installation of the fibrecrete via a purpose built flame proof shotcrete rig allows high impact placement of the fibrecrete onto the strata which ensures adhesion and infiltration of the fibrecrete into the coal strata to form a secure bond between the shotcrete layer tunnel arch structure and the roof/wall coal strata being supported. [00421 Accordingly, the above described method and apparatus provide a number of benefits over the art. [0043] A number of further features will now be described. [0044] In one example, the vehicle 200 includes a controller for controlling one or more aspects of operation of the vehicle. For example, the controller can be coupled to one or more sensors, the controller being adapted to receive signals from the sensor and selectively deactivate the engine depending on the received signals. The sensors can be for sensing gas and/or heat, allowing the controller to selectively deactivate the engine in the event that measured gas or heat levels exceed a predefined gas or heat levels, respectively. Additionally and/or alternatively, other action can be taken such as generating alarms to alert workers. 10045] The controller can be of any suitable form and typically includes an electronic processing device for receiving signals from the sensors, processing these and generating control signals. In one example, the electronic processing device is a microprocessor, microchip processor, logic gate configuration, firmware optionally associated with implementing logic such as an FPGA (Field Programmable Gate Array), or any other electronic device, system or arrangement capable of interacting with the sensors. [00461 The controller may also form part of a vehicle control system, such as a control system for operating the vehicle autonomously, as will be understood by persons skilled in the art. [0047] In one example, the engine provides power to the pumping system for pumping the material. This allows all power to be deactivated centrally in the event that the need arises, -8 whilst also reducing the need for multiple power systems, which would complicate use of the vehicle in underground mines. [00481 The vehicle typically also includes an electrical system, which allows the vehicle to operate safely in underground coal mines and within ERZ areas. [0049] It will be appreciated that the above vehicle can therefore be usable in or certified for use in an explosive risk zone such as an underground coal mine. 100501 A specific example of an apparatus for applying fibrecrete, in the form of a shotcrete rig, will now be described with reference to Figures 4A to 4D. [00511 In this example, the shotcrete rig 400 includes a shotcrete rig chassis having four wheels 411 and supporting a modified frame 412 that contains the flameproof engine (not shown). The material dispensing system is supported by the frame and includes a hopper 431 that contains the material in use, a movable boom 432, at least one spray nozzle 433 supported by the boom 432. Delivery hoses 434 are provided for coupling the spray nozzle 433 to the hopper 431, with a pumping system operating to pump material from the hopper 431 to the spray nozzles 433, thereby dispensing material from the spray nozzles. A feeder pipe 436 may also be optionally mounted to the hopper 431, whilst a scrubber tank indicator 437 can be mounted on a roof of the vehicle. The frame further supports hydraulic jacks 414 for additional vehicle stability and an operator cabin 415, as well as approved lighting 416. 100521 The flame proof engine is mounted in an engine compartment 413, and provides the power for travel and operation of the rig and concrete pumping components. The flameproof engine is specifically designed to be able to provide power for the rig in ERZ areas within a coal mine and has shutdown capabilities in case of excessive heat generation [0053] A radiator and/or scrubber system 417 is mounted to a rear of the frame to allow heat dispersal away from the engine, thereby reducing operator risk, as well as providing the radiator near available airflow to maximize cooling. [0054] The electrical system incorporates approved wiring, lighting and gas detection and shutdown systems, mounted in a control boxes 441, which provides shutdown of the machine in the event that excessive gas levels are detected within the work area. An electrical shut out -9 442 and engine shut out 443 are provided to allow for manual shut-down. Typically such features are mandatory for operation of vehicles in UG coal mining environments. [0055] In use, the vehicle can apply a fibrecrete layer by way of spraying fibrecrete at high velocities onto the coal/strata which provides a fibrecrete layer to the perimeter of the heading tunnel envelope. The fibrecrete is shot with such force that when it impacts onto the coal / strata, high adhesion is ensured as the fibrecrete infiltrates into the fissures of the coal strata. [0056] The thickness of the fibrecrete layer depends on the load resistance required and is defined by the mine site geotechnical engineer. Generally thickenings of the fibrecrete layer are provided at the intersection between the walls and roof and also at the toe of the walls. This provides extra load carrying capacity in terms of the stress points which exist at these points when load distribution occurs throughout the strata due to nearby mining activities and ground loadings. [0057] The thickness of the fibrecrete layer and the size and number of bolts required for secondary support is defined by the mine site geotechnical engineer and is designed to provide the most cost effective support model combination required for safe ongoing use of the heading/roadway for coal mining purposes. [0058] Throughout this specification and claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers or steps but not the exclusion of any other integer or group of integers. [0059] Persons skilled in the art will appreciate that numerous variations and modifications will become apparent. All such variations and modifications which become apparent to persons skilled in the art, should be considered to fall within the spirit and scope that the invention broadly appearing before described.