This relates to mining, in particular, to methods and apparatus for underground excavation, development and extraction.
Mining of underground deposits such as ore bodies requires excavation of very large quantities of material and transportation of such material to or toward the surface for processing. Handling of such materials requires heavy equipment, such as blasting or drilling equipment, material handling equipment, structural components, and the like. Some or all of such heavy equipment must be transported throughout the mine structure.
Typically, equipment, personnel and rock are moved using wheeled vehicles. Unfortunately, this technique has numerous deficiencies. For example, the inclination of mine tunnels is limited by the maximum incline on which wheeled vehicles can be safely operated. As a result, some formations cannot be mined in an economically viable manner using conventional methods.
In addition, the minimum dimensions of tunnels are defined by the space requirements for operation of vehicles. Moreover, movement of material by vehicles is inefficient and limits the rate at which material can be removed and processed.
Vehicles used in mines are commonly driven by internal combustion engines. Use of such engines underground poses problems. For example, mines must be effectively ventilated to remove internal combustion engine exhaust. Ventilation is very costly and insufficient ventilation can lead to unsafe air quality in the mine.
An example system for mining material in an underground tunnel comprises: a rail mounted to a roof of the tunnel; a tram comprising: a tram carriage supporting the tram on the rail, for movement along the rail; a tram conveyor mounted to the tram carriage, for movement of material relative to the tram carriage; a loader comprising: a loader carriage supporting the loader on the rail, for movement along the rail; a ramp having a loading conveyor for transporting material upwardly along the ramp, wherein the loader discharges material from an upper end of the ramp onto the tram conveyor.
An example method for mining material in an underground tunnel comprises: moving a tram carriage toward a face of the tunnel along a rail mounted to a roof of the tunnel; transferring fragmented rock from a loading ramp suspended from the rail to a conveyor on the tram carriage; moving the fragmented rock with the conveyor along a length of the tram.
An example system for mining in an underground tunnel comprises: a conveyor extending along the tunnel and supported on the floor of the tunnel, the conveyor operable to transport granulated material towards the surface; a rail extending along the tunnel and mounted to a roof of the tunnel above the conveyor, the rail operable to support wheeled machinery for transportation along the rail.
An example method of mining material in an underground tunnel comprises: moving fragmented rock along the tunnel on a ground-mounted conveyor; moving a loading device relative to the ground-mounted conveyor along a rail mounted to a roof of the tunnel, such that the loading device overlaps the ground-mounted conveyor; transferring fragmented rock from the loading device to the ground-mounted conveyor.
An example drilling apparatus for use in a mining tunnel comprises: a wheeled carriage for suspending the drilling apparatus from a rail on the roof of the tunnel; a frame depending from the wheeled carriage; a boom, comprising a tool holder having a drill mounted thereon; a pivotable joint connecting the boom and the frame, wherein the boom can be rotated around the pivotable joint.
An example drilling apparatus for use in a mining tunnel comprises: a frame movably suspended from a rail on a roof of the tunnel; a boom having a drill mounted thereon; a pivotable joint connecting the boom and the frame, wherein the boom can be rotated around the pivotable joint.
An example platform apparatus for use in a mining tunnel comprises a wheeled carriage for suspending the platform apparatus from a rail on the roof of the tunnel; a frame depending from the wheeled carriage; a working platform for elevating workers to access an end face or a ceiling of the mining tunnel; a linkage between the frame and platform operable to move the platform relative to the frame.
An example platform apparatus for use in a mining tunnel comprises: a frame movably suspended from a rail on the roof of the tunnel; a working platform for elevating workers to access an end face or a ceiling of the mining tunnel; an articulated linkage between the working platform and the frame.
An example method of mining material comprises: blasting a region of rock positioned vertically between overcut and undercut tunnels, to create a debris pile; moving a conveyor along a roof-mounted rail in the undercut tunnel, so that the conveyor is positioned to receive fragmented material from the debris pile; suspending a blade above the debris pile from a wire between the pulley and the conveyor; and drawing the blade across the debris pile with the wire to draw fragmented material onto the conveyor.
An example apparatus for mining material comprises: a first rail mounted along a roof of an overcut tunnel; a second rail mounted along a roof of an undercut tunnel, the undercut tunnel positioned below the overcut tunnel, wherein a void extends vertically between the undercut tunnel and the overcut tunnel; a conveyor mounted to the second rail in the undercut tunnel proximate the void; a blade suspended from a pulley on the first rail, the blade movable through the void across a debris pile to draw material from the debris pile onto the conveyor.
In the figures, which depict example embodiments:
Mine 100 includes a main tunnel 104, which may be inclined, and a plurality of secondary tunnels 106 which branch from main tunnel 104. Main tunnel extends proximate ore body 102. Secondary tunnels 106 extend away from main tunnel 104 and into ore body 102.tunnel
Generally, main tunnel 104 provides a path for machinery, personnel and material to be moved between the surface and working areas in the mine. For example, machinery, personnel and structural material may traverse main tunnel 104 and be used to extend the tunnel 104 or tunnels 106, or to break (e.g. drill or blast) material from ore body 102. Such activities may create fragmented waste rock and ore, referred to as muck, which may be removed to the surface by way of main tunnel 104.
Tunnels 106 communicate with main tunnel 104 and extend away from the tunnel 104 into ore body 102. Tunnels 106 are constructed to provide access to ore body 102 for extraction of resources.
Each tunnel 106 ends at a rock face 109. Excavation may be performed in cycles. That is, drilling or blasting may be performed at the face to break rock for removal. The resulting fragments, referred to as muck, may be removed, and then drilling or blasting may be repeated. Each repetition of this cycle adds a specific depth to the tunnel 106.
Each of main tunnel 104 and secondary tunnels 106 may be a straight linear corridor or may contain one or more curves. The radius of curves in a particular tunnel are subject to performance limitations of the apparatus used for transportation in that tunnel.
Junction section 112 is a portion of tunnel 106 proximate to the main tunnel 104. Junction section 112 includes features for permitting transfer of material and apparatus between tunnel 104 and tunnel 106.
Tunnel 106 is bounded by top and bottom surfaces, referred to respectively as the roof 114 and floor 116, and lateral surfaces referred to as walls.
Tunnel 106 contains a transport system. As shown, the transport system includes a rail 120 suspended from roof 114. Rail 120 is secured to roof 114 using a plurality of rock bolts spaced apart along the roof 114 of tunnel 106. The size, quantity and spacing of rock bolts may depend on, for example, the composition of ore body 102 and the surrounding waste rock; the length of drive 106; and the amount of weight expected to be borne by the transport system.
In the depicted embodiment, rail 120 is a monorail. Wheeled carriages 122 may be mounted to monorail 120 for movement along the monorail. Propulsion of the carriages 122 along monorail 120 may be achieved using any suitable drive system. For example, some carriages 122 may have an internal drive unit. The drive unit may include an electrical motor which may be provided power by way of a lead integrated with monorail 120 or proximate monorail 120. In some embodiments, the electrical drive may have a wheel to frictionally drive carriage 122 along monorail 120. In other embodiments, the electrical drive may have a geared interface with monorail 120 or with an auxiliary rack. As will be apparent, a geared interface may be capable of exerting greater motive force, and may be suitable for operation at large inclination angles.
Monorail 120 extends substantially the entire length of tunnel 106, such that carriages 122 on monorail can be moved from a proximal end where monorail and tunnel 106 interface with main tunnel 104, to a distal end where carriages 122 can position equipment for working on rock face 109.
Referring to
Rail 120 has an underside with a series of projecting teeth 127 defining a gear rack. Drive 125 has an output gear (not shown) with teeth configured to mesh with teeth 127. Alternatively, rail 120 may lack teeth 127, in which case drive 125 may interface frictionally with rail 120. In frictional-interface embodiments, rail 120 may optionally comprise a friction-increasing surface to increase traction for drive 125.
Although
Conveyor tram 130 has a frame 134. In the depicted embodiment, conveyor tram also has a chassis 136 mounted to carriages 122 proximate monorail 120 and between frame 134 and carriages 122. Chassis 136 houses a drive 137 operable to propel conveyor tram along monorail 120 as a unit. The drive may comprise an electrical motor and may have a frictional or geared drive interface.
A conveyor 138 is carried on frame 134. As shown, conveyor 138 is an endless belt conveyor. In the depicted embodiment, conveyor 138 has a belt 140 formed of metallic (e.g. steel) core links, covered with a polymer (e.g. rubber) later. Alternatively, belt 140 may be constructed of woven fabric or entirely of a polymer such as rubber.
Belt 140 is carried on a plurality of rollers, including one or more drive rollers 142 and one or more idler rollers 144. Drive rollers 142 are driven by an electric motor (not shown). The electric motor may be powered by an electrical lead integrated with or proximate to monorail 120.
As will be described in further detail, conveyor tram 130 is operable to receive a load of fragmented waste rock or resource material for removal from tunnel 106 to main tunnel 104 and subsequently, to the surface.
Conveyor tram 130 has two modes of moving material. Specifically, a first mode involves movement of the conveyor tram 130 along monorail 120. A drive acting between conveyor tram 130 and a support, such as monorail 122, is used to propel the conveyor tram towards or away from face 109. Conveyor tram 130 moves away from face 109 to unload material and towards face 109 to return for reloading.
In a second mode, belt 140 of the conveyor tram is moved by drive rollers 142. Belt 140 can be moved while the conveyor tram 130 itself moves along monorail 120. Alternatively, conveyor tram 130 can be moved while conveyor tram 130 is static.
Advancing belt 140 moves material relative to frame 134 and enables fragmented material to be loaded along the length of belt 140 from a fixed loading point. For example, material may be loaded onto conveyor tram 130 at an end close to the tunnel face 109, referred to herein as the distal end. As such loading occurs, continued movement of belt 140 moves the loaded material towards the opposite end, i.e. the end closest to main tunnel 104, referred to herein as the proximal end.
Likewise, material may be unloaded from conveyor tram 130 at a location near its proximal end. Advancing belt 140 moves loaded material from the distal end towards the proximal end for unloading.
Other cross-sectional arrangements are possible, as will be apparent. For example, rollers 144 may support belt 140 in a horizontal plane or in a trough shape, with a planar bottom and angled sides.
Referring again to
Like conveyor tram 130, muck loading apparatus 132 is suspended from monorail 120. Specifically, a frame 150 of the muck loading apparatus is suspended on carriages 122. A drive unit 152 is positioned in frame 150 and operable to propel muck loading apparatus 132 along monorail 120 towards and away from face 109. In the depicted embodiment, drive unit 152 comprises an electric motor, powered by a supply lead integrated with or positioned proximate monorail 120. Drive motor 152 may have a frictional or geared drive interface.
Frame 150 supports a ramp unit 154, a discharge unit 156 and an outrigger unit 158.
Ramp unit 154 has a distal end positioned nearest face 109 and a proximal end, positioned nearest main tunnel 104. Ramp unit 154 is supported near its proximal end by frame 150. Ramp 154 is pivotable relative to frame 150 about a horizontal axis, such that the distal end of ramp unit 154 can be pivoted toward roof 114 or toward floor 116. Ramp 154 is also pivotable relative to frame 150 about a vertical axis, such that it can be angled towards one or the other of side walls 118. As will be described in greater detail, ramp unit 154 is movable between stowed and operational positions.
As shown, the distal end of ramp unit 154 is positioned near floor 116 and the ramp unit 154 is angled upwardly so that its proximal end is positioned slightly above and near the distal end of conveyor tram 130.
Ramp unit 154 has a conveyor 160. Conveyor 160 may be an electric motor-driven endless belt conveyor, substantially similar to conveyor 138 of conveyor tram 130. Conveyor 160 may be driven at variable speed and is operable to move muck from the conveyor's distal end towards its proximal end, for loading onto conveyor tram 130 by way of discharge unit 156.
Outrigger unit 158 of the muck loading apparatus has a boom 162 mounted to and extending distally of frame 150. As depicted, frame 150 may be positioned near the end of monorail 120, such that boom 162 of outrigger unit 158 extends beyond monorail 120. Boom 162 is sufficiently long to span a distance between the end of monorail 120 and face 109 of tunnel 106. That distance corresponds to a minimum distance at which machinery must positioned relative to a blasted rock face for equipment operation and recovery of blasted material. In the depicted embodiment, the distance is 3 metres. However, the distance may be larger or smaller.
Boom 162 is supported near its proximal end by frame 150. Boom 162 is pivotable relative to frame 150 about a vertical axis, such that it can be angled towards one or the other of side walls 118 of the tunnel. Boom 162 may also be pivotable about a horizontal axis, such that the distal end of boom 162 can be pivoted toward roof 114 or toward floor 116 of the tunnel. Boom 162 may also be axially extendable towards or away from face 109.
Boom 162 supports a pulley 164 at the boom's distal end. A pulley wire 165 is looped in a circuit around pulley 164, a second pulley 166 at the distal end of ramp unit 154, and a third pulley 168 at the proximal end of boom 162.
A blade 170 is mounted to pulley wire 165. Blade 170 can be reciprocated by movement of wire 165 through a stroke between pulley 164 at the distal end of boom 162 and second pulley 166 at the distal end of ramp unit 154.
Blade 170 rests atop a muck pile 172 produced by breaking (e.g. drilling and blasting) of face 109. Pulling of blade 170 through its stroke towards ramp unit 154 pulls fragmented rock onto conveyor 160 of the ramp unit.
At the proximal end of conveyor 160, fragmented rock falls from conveyor 160 to discharge unit 158. Discharge unit 158 comprises a chute (not shown) for directing the rock onto the conveyor of conveyor tram 130.
It is desirable for rock to be evenly distributed along conveyor 138 of conveyor tram 130. Even distribution avoids concentration of loads on the conveyor. To this end, discharge of rock from ramp unit 154 to conveyor tram 130 may be metered.
In some embodiments, metering is achieved by adjusting speeds of conveyor 160 and conveyor 138. For example, conveyor 138 and conveyor 160 may be held at substantially identical linear speeds so that rock does not accumulate on conveyor 160. Alternatively, conveyors 138 and 160 may be held at linear speeds in a constant ratio to one another, such that accumulation of rock is consistent.
In some embodiments, discharge unit 158 may be equipped with a discrete metering device. For example, discharge may be metered through an orifice to limit the flow rate of fragmented rock onto conveyor 138. Additionally or alternatively, a measurement device such as a metering wheel, a machine vision system, or a conveyor load cell could be used to measure the quantity of rock discharged onto conveyor 138.
In some embodiments, multiple rails 120 may be provided within tunnel 106. For example,
Rails 120-1, 120-2 may be coextensive. That is, both rails 120-1, 120-2 may extend from a junction with main tunnel 104 to distal ends at substantially identical distances from face 109. Each rail 120 is capable of supporting apparatus such as conveyor tram 130 or muck loading apparatus 132. As depicted, rails 120-1, 120-2 respectively support conveyor trams 130-1, 130-2.
Rails 120-1, 120-2 provide flexibility for performing multiple operations within tunnel 106. For example, as shown in
Rails 120-1, 120-2 also provide flexibility of movement within tunnel 106. Specifically, one piece of apparatus could move in the distal direction of tunnel 106 along rail 120-1. A second piece of apparatus could move in the proximal direction of tunnel 106 along rail 120-2. Such pieces of apparatus could pass one another while moving in opposite directions.
In some embodiments, a crossover mechanism may be provided between multiple rails 120. For example,
Carriages 122-1, 122-2 are mounted to a first rail 120-1. Additional carriages 120-3, 120-4 are mounted to a second rail 120-2. As shown in
As shown in
Thus, after the two pivots, frame member 129 moves from being carried on rail 120-1 to being carried on rail 120-2.
In some examples, the releasable connections between frame member 129 and carriages 122 may be locked and released by manual insertion or removal of pins.
In addition to conveyor tram 130 and muck loading apparatus 132, other types of apparatus may be supported on rails 120.
Drilling apparatus 200 is operable to drill holes in any of roof 114, floor 116, walls 118 and face 109 of tunnel 106. Such holes may, for example, be for securing ground support hardware or for inserting explosives for blasting.
Drilling apparatus 200 has a frame 202 supported by a plurality of carriages 122 on rail 120. Drilling apparatus 200 also includes a drive unit 125 operable to propel drilling apparatus 200 along the length of rail 120. The drive unit 125 may drive apparatus 200 frictionally or using a geared interface.
A boom 206 extends from frame 202 toward face 109. As previously noted, the distal end of rail 120 is typically spaced apart from face 109 by a distance corresponding to the minimum safe distance from a blast event. Boom 206 is sufficiently long to reach across such spacing so that the end of boom 206 can perform operations on face 109.
Boom 206 comprises a support link 210 and a tool carrier 212. Support link 210 is connected to frame 202 by way of a joint 214. Support link 210 is pivotable relative to frame 202 around joint 214. Joint 214 permits rotation of support link 210 at least in a horizontal plane. Support link 210 can also be axially extended or retracted, e.g. by an electrical, hydraulic or pneumatic actuator.
Tool carrier 212 is connected to support link 210 by way of a pivotable joint 216. Joint 216 permits tool carrier 212 to rotate in at least two axes relative to support link 210. Specifically, tool carrier can be rotated in a horizontal plane parallel to that in which joint 212 can be rotated, and in a second, orthogonal direction around a horizontal axis parallel to the support link 210. Drilling apparatus 200 is therefore able to reach a large portion of face 109 and the surrounding roof 114, floor 116 and walls 118 of tunnel 106.
Movement of boom 206 around joints 214, 216 may be effected by actuators, which may for example be electrically operated actuators, such as servomotors, or hydraulic or pneumatic pistons. Other suitable actuators are possible, as will be apparent to skilled persons.
Tool holder 212 is mounted to the distal end of support link 210 at approximately the midpoint of tool holder 212 and may be pivoted so that either end of the tool holder can be positioned to face any of roof 114, floor 116, walls 118 or face 109. Tools may be mounted at both ends of tool holder 212. In the depicted embodiment, the tools are electrically operated drills with bits suitable for drilling in rock. The bits may be removable, such that they can be easily replaced or exchanged with other bits suited to the composition of rock surrounding tunnel 106.
Drilling apparatus 200 is operable in a first mode, depicted in
Support link 210 may be moved around joint 214 to reposition the drills relative to walls 118. Thus, by articulation of boom 206, holes may be drilled in walls 218 in substantially any desired pattern.
In a second mode, depicted in
In a third mode, depicted in
Drilling apparatus 200 can also be operated in a transport mode, depicted in
Platform 224 is operable to support workers or apparatus for working on any of roof 114, floor 116, side walls 118 and face 109. For example, platform 224 may be used to elevate workers to install support structure to roof 114, or to insert explosive charges in face 109. Other applications are possible, as will be apparent. Platform 224 has guard rails 225 for protecting against falls by workers. Guard rails 225 are pivotably attached to platform 224, such that the guard rails can be selectively fixed in an upright position, e.g. using pins, or collapsed to lie flat against platform 224.
Linkage 226 is configured so that platform 224 can be held in a horizontal orientation in a wide range of possible locations. Specifically, axial extension or retraction of linkage 226 and articulation of linkage 226 around joints 228, 230 may allow platform 224 to be held in a horizontal position while providing access to any portion of roof 114 between the ends of tracks 120 and face 109, or to any portion of face 109.
An explosives transportation unit 232 may also be supported on tracks 120. The explosives transportation unit 232 may be integrally formed with platform apparatus 220 and supported on frame 222. Alternatively, explosives transportation unit 232 may have a separate frame and be supported on separate carriages 122, and moved into proximity with platform apparatus 220.
As depicted, explosives transportation unit 232 is equipped with tooling for workers to transfer explosive charges into holes bored in face 109 using drilling apparatus 200. In the depicted embodiment, the tooling comprises nozzles for injecting explosive material in a flowable form, e.g. a slurry. However, other tooling is possible, for transferring explosives in different forms. The tooling may also be capable of inserting ignition devices, e.g. wires for electrical ignition, which may be operated remotely.
Platform apparatus 220 is also operable in a transport mode, as shown in
Any apparatus supported from tracks 120, including conveyor tram 130, muck loading apparatus 132, drilling apparatus 200, platform apparatus 220 and explosives transportation unit 232, may be equipped with stabilization devices for stabilizing the apparatus during operation.
Stabilization device 240 includes an anchor tip 242 for engagement with roof 114, floor 116, side walls 118 or face 109 of tunnel 106. Anchor tip 242 is mounted on a linear actuator which is extendable to urge anchor tip 242 into contact with roof 114, floor 116, side walls 118 or face 109. The actuator may, for example, comprise a hydraulic or pneumatic cylinder, or an electro-mechanical drive such as a ball screw.
Anchor tip 242 may be formed of a material of sufficient hardness to dig into roof 114, floor 116, side walls 118 or face 109. For example, the anchor tip may be formed of a suitable tool steel or carbide. Alternatively or additionally, anchor tip 242 may have a high-friction surface for frictionally engaging roof 114, floor 116, side walls 118 or face 109. Thus, when anchor tip 242 is urged into contact with roof 114, floor 116, side walls 118 or face 109, the anchor tip 242 grips the roof 114, floor 116, side walls 118 or face 109 and braces the frame against relative movement between the frame and the roof 114, floor 116, side walls 118 or face 109.
Stabilization device 240 has an adjustable base 244. Adjustable base 244 is pivotably mounted to the frame, and has an actuator such as a hydraulic or pneumatic cylinder or servo operable to adjust the orientation of base 244 and of stabilization device 240 relative to the frame. The orientation may be chosen based on the loads expected to be imposed on the frame. For example, stabilization device 240 may be oriented substantially vertically to brace drilling apparatus 200 for drilling in roof 114. Stabilization device may be angled outwardly towards walls 118 to brace against lateral loads, e.g. for drilling in walls 118. Optionally, multiple stabilization devices 240 may be provided on the same piece of equipment, and may be oriented at different angles to provide bracing in multiple directions.
In some embodiments, stabilization devices 240 may be installed to portions of equipment other than frames. For example, instead of or in addition to the respective frames, stabilization devices 240 may be provided on any of outrigger unit 158, ramp unit 154 or discharge unit 156 of muck loading apparatus 132; boom 206 of drilling apparatus 200; or platform 224 of platform apparatus 200.
At box 302, a pile of fragmented rock material, referred to as a muck pile, lies proximate face 109 of tunnel 106. Muck loading apparatus 132 is advanced to the distal end of rail 120 (see
Outrigger unit 158 is extended over the muck pile so that its distal end is positioned proximate face 109 and roof 114. Blade 170 is drawn towards the distal end of outrigger unit 158 and allowed to rest atop the muck pile.
Ramp unit 154 is also extended towards the muck pile and its distal end is lowered to rest on floor 116 proximate the muck pile. The conveyor 160 of ramp unit 154 is activated for moving material from its distal end towards its proximal end.
Discharge unit 156 is positioned to receive material from the proximal end of ramp unit 154 and direct the material onto the distal end conveyor 138 of conveyor tram 130. Conveyor 138 is also activated for moving material from its distal end towards its proximal end.
Wire 165 is then moved to drag blade 170 down the muck pile towards ramp unit 154 and, subsequently, to return blade 170 to the top of the muck pile. Blade 170 continues to be reciprocated through this path.
With each pass of blade 170 down the muck pile and towards ramp unit 154, the blade pulls muck material from the top of the pile and onto ramp unit 154. The ramp unit 154 then lifts the muck material to discharge unit 156.
As noted, discharge unit directs the received material onto the distal end of conveyor 138 of conveyor tram 130. As noted, speeds of conveyor 160 and conveyor 138 may be matched so that fragmented material is evenly distributed along the length of conveyor 138. Additionally or alternatively, discharge unit 156 may have a restrictor device limiting the rate at which material can be deposited onto conveyor 138. In some embodiments, conveyor 138 may be advanced in discrete increments, rather than continuously, so that rock material is discharged onto conveyor 138 in discrete piles.
Loading of conveyor 138 in this manner continues until the entire upward-facing length of conveyor 138 is loaded with material. Conveyor tram 130 is then moved along rail 120 towards main tunnel 104 to offload material.
Removal of material from the muck pile may pause until the conveyor tram returns after unloading, or until another conveyor tram 130 arrives to receive material. At that point, material removal continues in the same manner.
During removal of muck, ramp unit 154 and outrigger unit 158 may be repositioned to collect material from different parts of the muck pile. For example, ramp unit 154 and may be twisted to a different angular orientation relative to rail 120, such that material can be collected from portions of the muck pile adjacent side walls 158.
Removal of material continues until the muck pile is substantially entirely removed. Thereafter, face 109 and the surrounding area are prepared for a new blast.
At box 304, drilling apparatus 200 is advanced to the distal end of rails 120 and boom 206 is extended toward face 209. Boom 206 is moved to the drilling configuration of
At box 306, platform apparatus 220 is advanced to the distal end of rail 120 and platform 224 raised into position so that workers on platform 224 can access roof 114. Workers install rock bolts into the holes bored at box 304. Reinforcing structure is installed using the rock bolts. The reinforcing structure may include, for example, metal bars or arches, metal mesh, pillars, or any suitable structure, as will be apparent to skilled persons. The supporting structure may include devices for anchoring rail 120.
In embodiments with a single rail 120, drilling apparatus 200 is removed prior to platform apparatus 220 being moved towards face 109. In embodiments with multiple rails 109, platform apparatus 220 may be moved towards face 109 on another rail, while drilling apparatus 200 is held in its working position.
At box 308, drilling apparatus is moved into a working position proximate face 109 (if necessary) and boom 206 is moved to the position of
At box 310, platform apparatus 220 is moved into a working position near face 109 and workers supported on platform 224 install explosive charges into holes drilled at box 308. Explosives transportation device 232 is moved into position behind platform apparatus 200 and explosive charges are injected through nozzles.
After installation of explosives, all personnel and machinery are moved in the proximal direction away from face 109, to a safe distance for blasting. The safe distance may depend, for example, on characteristics of the formation being blasted, and the number and size of charges, as will be apparent.
Explosives are detonated at box 312. Detonation may be triggered remotely by any suitable method.
Immediately after face 109 of tunnel 106 is blasted, a section of rock is broken down into fragmented material, leaving a new face 109 distal of the face that was blasted. The new face 109 is spaced apart from rail 120 by a distance defined by the depth of the blasted rock section, plus the safety margin by which rail 120 was spaced apart from the previous face immediately prior to the blast.
After blasting, at box 314, the new face 109 and surrounding sections of roof 114, floor 116 and side walls 118 are inspected visually and with the aid of instruments to verify stability and safety for further work.
Inspection may be performed by workers atop platform 224 of platform apparatus 220. Specifically, platform apparatus 220 may be advanced to the distal end of rail 120. Platform 224 is extended toward the new face 109 by articulation of linkage 226. Platform 224 may be moved laterally and vertically up and down across face 109.
Upon satisfactory inspection, at box 316, a section is installed for each rail 120. The new sections mate to the existing rails, such that carriages 122 supporting apparatus can me moved from the existing rail onto the new section. The process then returns to box 302 for removal of fragmented material from the blast.
Process 300 repeats to propagate tunnel 106 in a distal direction away from its starting point.
Main tunnel 104 is equipped with a ground-mounted conveyor 400. Conveyor 400 may include an endless belt 402 driven by one or more electrical drive rollers (not shown), which may be operated at variable speed. Conveyor 400 may further be supported by one or more idler rollers (not shown). The endless belt 402 may have a plurality of spaced elevator partitions 404 attached thereto.
A loading chute 406 may be positioned above the conveyor 400 at a junction with a tunnel 106, to receive fragmented material from a conveyor tram 130 within the tunnel and direct the fragmented material onto conveyor 400. Specifically, rock material falling into loading chute 406 is directed into a pocket defined by an elevator partition 404. Conveyor 400 may be constantly or intermittently advanced to carry a filled elevator partition 404 away from chute 406 and towards the surface.
Loading of fragmented rock into each elevator partition 404 may be metered. Metering may be achieved, e.g., using a measurement device on or proximate conveyor tram 130 to measure the amount of rock discharged. Additionally or alternatively, metering may be achieved by providing a fixed-size aperture on chute 406 and advancing conveyor 400 at a defined rate, such that each elevator partition 404 receives a maximum weight of material. Additionally or alternatively, one or more load sensors may be positioned on or under endless belt 402 or elevator partitions 404 to directly measure the load imposed on each elevator partition 404. Controlling load in this way may contribute to durability and reliability of conveyor 400.
Conveyor 400 is of modular construction. Specifically, conveyor 400 includes a plurality of sections, each having: a structure for supporting conveyor 400 on the floor of main tunnel 104; a portion of belt 402 with one or more elevator partitions 404; and on one or more rollers supporting the belt portion. In some embodiments, all sections of conveyor 400 include at least one drive roller. In other embodiments, drive rollers may be present in only a subset of conveyor sections, e.g. every second section or every fourth section.
In the depicted embodiment, belt 402 has a core comprised of metallic links, with an outer cover. The outer cover may be, for example, woven fabric such as nylon fabric, or a resilient flexible polymeric layer such as a rubberized sheath.
Portions of belt 402 are connected by splice joints 410, depicted in
Tunnels can be excavated horizontally, with an incline gradient, or with a decline gradient. As depicted, main tunnel 104 is excavated downwardly as extraction from ore body 102 progresses. That is, tunnels 106 are excavated in sequence from top (closest to the surface) to bottom (farthest from the surface). Main tunnel 104 is correspondingly extended downwardly to service new tunnels 106.
As shown in
Any of conveyor tram 130, muck loading apparatus 132, drilling apparatus 200, platform apparatus 220, and explosives transportation unit 232 may be supported on and moved along rail 120, and may be used to excavate main tunnel 104 substantially as described above with reference to tunnel 106. That is, main tunnel 104 may have an end face 109′ and main tunnel 104 may be extended in steps by blasting a section of rock behind end face 109′ to define a new end face, and removing the blasted rock before blasting again.
As shown in
In other embodiments, a conveyor tram 130 may be arranged in series behind muck loading apparatus 132 and overlapping conveyor 400, such that fragmented material is transferred from the muck loading apparatus 132 to the conveyor tram 130, and then to conveyor 400.
With each blast at the end of main tunnel 104, face 109′ is extended farther away from conveyor 400. Conveyor tram 130 and muck loading apparatus 132 may move towards the new face 109′ such that they continue to span the gap. However, the overlap between components correspondingly decreases.
Conveyor tram 130 and muck loading apparatus 132 continue to incrementally move away from conveyor 400 with successive blasts, until a minimum overlap between muck loader 132 and conveyor tram 130 is reached, or until a minimum overlap between conveyor tram 130 and conveyor 400 is reached. In some embodiments, the minimum overlap may be zero, such that tram 130 and muck loading apparatus 132 incrementally move away from conveyor 400 until there is no overlap. An additional section may then be installed to extend conveyor 400 so that the conveyor and the tram 130 again overlap, and continue blasting.
Thus, an additional section of conveyor 400 is installed for each set of blasts that cumulatively adds a distance to main tunnel 104 equivalent to the lengths of conveyor tram 130 and muck loading apparatus 132, less the overlaps required for operation. In an example, conveyor tram 130 is 30 metres in length and muck loading apparatus 132 spans a length of 12 metres.
In the absence of conveyor tram 130, new sections would have to be added to conveyor 400 much more frequently. Depending on the depth of each blast, new conveyor sections could be required after every blast.
Conveyor 400 must be stopped in order to add a section. Therefore, the use of conveyor tram 130 intermediate conveyor 400 and muck loading machine 132 may avoid operational interruptions, and in turn, may increase productivity for mine 100.
In some embodiments, new sections may be added to conveyor 400 even less frequently. For example, blasting could continue until the gap distance G between conveyor 400 and face 109′ is greater than the combined lengths T, L of conveyor tram 130 and muck loader 132. In such configurations, conveyor tram 130 may be loaded with fragmented material, then moved along rail 120 towards conveyor 400 until they overlap, prior to discharging the fragmented material onto conveyor 400.
In some embodiments, a modified conveyor tram may be used in main tunnel 104.
Like conveyor tram 130, conveyor tram 130′ is supported on a rail 120 by way of carriages 122 (not shown). Conveyor tram 130′ may also have a drive unit operable to propel conveyor tram 130′ along rail 120 by friction or by a geared interface. Additionally or alternatively, tram 130 may be propelled by an external drive. For example, conveyor tram 130′ may be attached to a lifting device 702 such as a jack or a winch by way of a cable 704. The lifting device 702 may be mounted to the tunnel roof, as shown, or to the tunnel floor, or suspended on rail 120.
Conveyor tram 130′ has a conveyor with a belt 706.
As depicted in
Lifting device 712 is operable to move conveyor tram 130′ up or down tunnel 104, thereby increasing or decreasing the length of main section 710 that overlaps conveyor 400.
In operation, as shown in
As noted, conveyor 400 is installed in sections. At the time a section is installed, it is spaced apart from the face of tunnel 104 by the minimum safe distance. Conveyor tram 130′ is extended to bridge the gap between the face and conveyor 400. Subsequent blasts move the face farther away from the conveyor 400, such that conveyor tram 130′ needs to bridge a larger gap. To do so, conveyer tram 130′ may be extended farther, resulting in a smaller overlap between main section 710 and conveyor 400. The range of distance that can be serviced with conveyor tram 130′ is defined by the length l of its main section 710. A new section of conveyor 400 is installed each time a set of blasts cumulatively increase the length of tunnel 104 by distance l.
In some embodiments, the length l is longer than a section of conveyor 400. Accordingly, new sections of conveyor 400 may be installed less frequently that would be required in the absence of conveyor tram 130′. In some examples, length l may be a multiple of the length of a conveyor section. In such an example, multiple conveyor sections may be installed each time operation of conveyor 400 is interrupted for addition of a section.
Loading section 712 and ramp section 714 may be supported on the floor of tunnel 104. For example, the loading section and ramp section may be supported on wheels which carry at least part of the weight of conveyor tram 130′. Alternatively, loading section 712 and main section 714 may be supported by fixed support structures.
Loading section 712 and ramp section 714 may be pivotably connected to main conveyor 400. For example, ramp 714 can be pivoted between an operational position in which ramp 132 rests against the floor of tunnel 104 (
To install a new section of conveyor 400, the conveyor is stopped. Prior to stopping, conveyor 400 may be unloaded of fragmented material. A support structure is erected on the floor of main tunnel 104 between the existing conveyor 400 and face 109′. Rolling elements are installed to the support structure for supporting belt 402. As noted, the rolling elements include at least one idler roller and may include one or more drive rollers.
A splice joint 410 at the lower-most end of belt 402 is released and a new section of belt is wrapped around the newly-installed rolling elements. Links 412 at both ends of the new belt section are aligned in registration with corresponding links 412 from the released splice joint 410. The registered links 412 are then locked together to form closed splice joints 410, joining the new section into belt 402.
Conveniently, conveyor 400 and rails 120 may in concert be capable of transporting apparatus, material and personnel up an incline substantially steeper than could be achieved with conventional ground vehicles such as trucks. Accordingly, main tunnel 104 may likewise be steeper than a tunnel designed to be serviced by trucks. For example, trucks may typically be capable of moving apparatus, material and personnel up a grade of 15% or less. In contrast, using conveyor 400 and rails 120, apparatus, material and personnel may be moved up a 58% grade or more.
As will be apparent, excavation of main tunnel 104 at a steeper incline may permit access to ore body 102 with a shorter main tunnel 104, shorter tunnels 106, or both. Accordingly, the cost of accessing the ore body may be substantially lower. Moreover, rails 120 and conveyor 400, operating in concert, may permit removal of material at a higher rate, further lowering the cost of resource production. Such lower costs may enable some resource deposits to be mined profitably which would not be profitable using conventional techniques. In addition, some resources may be physically inaccessible using conventional techniques but capable of mining using apparatus and methods disclosed herein.
In addition to excavation of material from main tunnel 104 and tunnels 106, apparatus and methods disclosed herein may be used for removing portions of ore body 102 between tunnels 106.
At box 602 and as shown in
Drill holes 502 may be bored by drilling apparatus 200 or another suitable drilling rig and are drilled in a pattern designed to break and fragment a portion of block 500. Each drill hole comprises a hollow bore in which explosives may be inserted, such that they rest at the lowermost portion of block 500 within the blast region.
At box 604 and as shown in
At box 606 and as shown in
At box 608, muck loading apparatus 132 and conveyor tram 130 are moved into place in tunnel 106-2 along rail 120 and fragmented material from pile 504 is loaded onto conveyor tram 130 and removed until material is able to slough from pile 504 towards tunnel 106-2, where it can be removed by muck loading apparatus 132.
If part of block 500 within the blast region remains intact, the process returns to box 604 and another set of explosive charges is installed in drill holes 502 for another round of blasting and material removal. The explosive charges may be positioned at the bottom of drill holes 502 by first dropping a plug down each drill hole to stop the explosive charge.
When the entirety of block 500 within the blast region has been blasted, a void is left between overcut tunnel 106-1 and undercut tunnel 106-2. At box 610 and as shown in
The positions of pulleys 512 can be moved along rail 120 to alter the stroke of blade 170. For example, as shown in
When pile 504 is substantially cleared, if part of block 500 remains to be excavated, the process returns to box 602 and repeats for another part of block 500. If all of block 500 has been blasted and removed, the resulting void is filled with backfill material. The process then moves to another block to to be excavated.
Material removal by process 600 may be relatively efficient. That is, material may be removed at a high rate or at a low cost compared to conventional processes.
The embodiments detailed herein are intended as examples only and are in no way limiting of the invention. Modifications are possible, as will be apparent to skilled persons. The invention is therefore defined by the claims, as interpreted in view of the application as a whole.
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/US2019/049307 | 9/3/2019 | WO |