Patent Application
20200040725
This application relates to the field of mining, and more specifically, to a rapid development mobile canopy (or rapid advance shield) for underground mining.
Current drill and blast advance rates are only approximately 4 m/day even when the most efficient and powerful equipment in the mining industry is used. As little as 25 years ago, advance rates of 12 m/day or more were commonplace. Today, the safest and most efficient tunnel-advance technique is the tunnel-boring machine which is being developed for application to very large regular shaped ore-bodies, such as copper porphyries. Most underground base metal mines are too small and too irregular in shape to make use of this kind of technology.
The batch drill-and-blast method has definite advantages in highly stressed grounds where seismic activity is prevalent. Blasting can be used to proactively initiate the seismic release of energy and the combination of pinned mesh coverage allows for surface expansion before rigid shotcrete support is added for long term stability.
The batch drill-and-blast method can be broken down into three stages: removal of broken rock from the heading; face-advance activities, which include drilling holes and loading explosives; and, ground support (i.e., roof and wall support) installation. Currently, the process of installing ground support is the most-time consuming component of this method and given the challenging safety and stability conditions encountered in deep mining, the quality of the final installation of this component should not be compromised. In fact, in some cases, protection from instabilities at the face may also have to be provided.
Two important characteristics of the tunnel-boring technique are as follows. First, the reduction of exposure of operating personnel to the danger of rock-related injuries in the heading. Second, the simultaneous application of face-advance and ground support activities. Just as personnel are protected inside the tunnel boring machine, so must batch drill-and-blast personnel be protected from exposure to rock-related risks at all times. To be more productive, any new batch drill-and-blast method must emulate the simultaneous implementation of face-advance and ground support activities to increase the rate of advance.
One existing mobile canopy for underground mining is described in International Patent Application Publication No. WO 2014/047721 by Morrison, which is incorporated herein by reference.
As described by Morrison, batch drill-and-blast mining involves essentially three activities, which can be broadly categorized as: 1) removal of broken rock from the heading; 2) face production; and 3) ground support. For reference, the horizontal mining tunnel in which work is taking place and where workers are present may be referred to as the “drift”. The “tunnel face” is the part of the mine where advancement of the mining tunnel or drift takes place. Typically, this will consist of the vertical rock surface at the end of the drift. The “heading of the drift” is that portion of the mine near the tunnel face which contains the broken rock following a blast. The heading comprises the roof, walls, and ground surfaces of the drift. Removal of broken rock from the heading occurs after the explosives embedded in the tunnel face have been detonated. This step is referred to as “mucking”.
As taught by Morrison, and referring to
In the batch drill-and-blast method of Morrison, the protection provided by the mobile canopy allows for ground supporting activities to take place at the same time as the face production crew is at work. Ground support activities typically involve applying shielding to the roof and wall surfaces of the drift to protect against random rock falls or rock bursts. The shielding may be in the form of mesh coverage, which is standard in the industry. The shielding is attached to the roof and wall surfaces of the drift using standard techniques, such as rock bolting or doweling.
As taught by Morrison, the ground support activities take place behind the mobile canopy, or in some cases, can involve part of the mobile canopy. Having the mobile canopy positioned at or near the heading allows for face production work to proceed before the ground support activities have been completed. Traditionally, the heading would have to be secured before the face production crew could enter and begin work. However, as taught by Morrison, the mobile canopy provides protection to the face production crew while the ground support crew performs its activities. This arrangement allows for more rapid turnaround between blasts.
Referring to
According to Morrison, the vertical supports 10 are provided to support the frame 11 and position it near the roof of the drift. Since the main purpose of the mobile canopy 1 is to protect workers and machines positioned underneath the canopy from falling rock, the vertical supports 10 are made from a material that is strong enough to support such an impact. As such, steel is a preferred material for the supports. In one embodiment, the vertical supports 10 are capable of being lengthened so that the height of the mobile canopy 1 can be adjusted to accommodate irregularities in the height of the drift. For example, hydraulic or screw jacks or pneumatic cylinders 20 can be provided within the vertical supports 10 or attached thereto to allow for adjustment of the length of the supports 10.
According to Morrison, the vertical supports 10 of the mobile canopy 1 can also be connected to wheels 21 to allow movement of the canopy 1 within the drift. Alternatively, the vertical supports 10 may engage rails provided in the drift to permit movement of the canopy 1. For example, the engagement of the vertical supports 10 and the rails may occur through the wheels provided on the supports.
According to Morrison, lateral movement of the covered structures 5, 6, 61 can be limited by including lateral supports 62 on the vertical supports 10 or the frame 11. Similar to the vertical supports 10, the lateral supports 62 are capable of being lengthened to accommodate irregularities in the width of the drift 2.
According to Morrison, in most cases, a vertical support 10 will be positioned at each corner of the frame to provide adequate support to the covered structure. However, additional support may be achieved by positioning a leg 50 along each longitudinal side of the frame central to the two vertical supports 10. Depending on the overall length of the longitudinal sides of the frame 11, a plurality of legs 50 may be provided interspaced between the two corner vertical supports 10. In the embodiment shown in
According to Morrison, the vertical supports 10 are connected to a frame 11, which supports a shield 12. The frame consists of two longitudinal sides 30 and may be interconnected by at least cross members 32 positioned on or near either end of the longitudinal sides 30. The overall strength and support of the canopy 1 can be improved by providing additional cross members 32 between the two end cross member 32 sections. In addition, longitudinal supports 63 can be provided to connect adjacent cross members 32 as shown in
According to one preferred embodiment described by Morrison, a shield 12 overlays the frame 11. However, the shield 12 can also be hung from the frame 11. The shield 12 is preferably made from mesh coverage, which is typically used in the mining industry to support the roof and walls of the drift 2. The shielding material may include 4 inch welded wire mesh, (#6 or #4 gauge) or chain link mesh of similar gauge. Alternatively, as shown in the covered structure 61 of
According to Morrison, in order to provide added protection to the workers positioned under the mobile canopy 1, wall shielding 40 may also be provided on the longitudinal sides of the covered structures 5,6. In this case, the wall shielding 40 may be extended from the longitudinal sides 30 of the frame 11 to or near the floor of the drift 2 or may be extended to a height between the floor of the drift 2 and the frame 11. The wall shielding 40 can be made of a similar material as provided for the shield 12, i.e., mesh coverage or longitudinal supports 63, or a combination of materials may be used depending on the situation. In addition to the wall shielding 40, or separate therefrom, front facing shielding 42 may be provided from one of the end cross members 32 on the frame 11. The front facing shielding 42 prevents or limits the possibility of injury from rock displacements that occur at the tunnel face. The front facing shielding 42 can be made from the same material as used for the shield 12 or may be a chain mesh that is hung from the end cross member 32 of the frame 11.
According to Morrison, in one arrangement, the mobile canopy 1 comprises at least two covered structures 5, 6. In another, preferred arrangement, the mobile canopy 1 includes three independent covered structures 5, 6, 61 as shown in
According to Morrison, when the mobile canopy 1 comprises at least two covered structures 5, 6, 61, the structure (5 or 61) closest to the face can be provided with front facing shielding 42 as described above. In this case, it may not be necessary to provide such shielding on the second structure (6 or 5), since injury resulting from rock displacements on the face will be less of a concern. However, curtains 64 can be provided between the covered structures 5, 6, 61 to prevent overhead debris from entering the protection of the mobile canopy 1. In one embodiment, the curtains 64 are heavy material having some slack in order to gather any debris that might fall from overhead. In another embodiment, the covered structure 5 that is positioned nearest the heading is covered by mesh sheets 1.3 m by 4 m, lengthwise so there is some overlap between the two covered structures 5, 6. The leading covered structure 61, i.e., the one positioned closest to the heading 3, may be provided so that the frame 11 and wall shielding 40 are more permanently connected to vertical supports 10. As described above, longitudinal supports 63 connecting the cross members 32 and the vertical supports 10 provide a more permanent and solid structure.
According to Morrison, although both covered structures 5, 6 can have identical characteristics, it is preferred that at least the structure 6 farthest from the tunnel face be provided so that the shield 12 can be detached from the frame 11 and used in the ground support activities. In particular, the shield 12 is detached from the frame 11 and bolted to the roof of the drift 2. In this embodiment, the second covered structure 6 will comprise of standard mesh width-wise across the drift, so as to enable the normal installation of mesh and pattern reinforcement. Similarly, the wall shielding 40 can be detached from the frame 11 and/or vertical supports 10 and used to support the walls of the drift 2. By providing detachable shielding on the second structure 6, the amount of time required to complete the ground support activities can be decreased.
According to Morrison, typically the covered structure (5 or 61) that is positioned closest to the heading 3 will have shielding that is meant to only be removed when damaged. However, this structure may also have detachable shielding that can be used in ground support activities.
One problem with existing mobile canopies such as that of Morrison is that they are often difficult to move and position within a drift. In addition, the sizing of existing mobile canopies is typically difficult to adjust while within a drift.
A need therefore exists for an improved mobile canopy (or rapid advance shield) for underground mining. Accordingly, a solution that addresses, at least in part, the above and other shortcomings is desired.
According to one aspect of the application, there is provided a mobile canopy (or rapid advance shield) for use in a tunnel, comprising: first and second opposing and spaced walls; a curved (or arched) roof coupled between the first and second walls; first and second skis mounted to respective bottoms of the first and second walls, the skis adapted to slide the mobile canopy about a floor of the tunnel; wherein the curved roof slopes downward from a front end of the mobile canopy toward a back end of the mobile canopy, the front end of the mobile canopy for positioning adjacent to a face of the tunnel; wherein the curved roof is movable between a first position proximate a roof of the tunnel and a second position spaced from the roof of the tunnel; and, wherein the first and second walls are movable between respective first positions proximate respective walls of the tunnel and respective second positions spaced from the walls of the tunnel.
According to another aspect of the application, there is provided a method for advancing a tunnel face in an underground mine, comprising: blasting the tunnel face with explosives; removing debris generated by the blasting from a heading of the tunnel; positioning a mobile canopy (or rapid advance shield) at or near the heading; drilling holes in the tunnel face and packing the holes with additional explosives; and, securing the tunnel from inside the mobile canopy; wherein the mobile canopy includes: first and second opposing and spaced walls; a curved (or arched) roof coupled between the first and second walls; first and second skis mounted to respective bottoms of the first and second walls, the skis adapted to slide the mobile canopy about a floor of the tunnel; wherein the curved roof slopes downward from a front end of the mobile canopy toward a back end of the mobile canopy, the front end of the mobile canopy for positioning adjacent to the tunnel face; wherein the curved roof is movable between a first position proximate a roof of the tunnel and a second position spaced from the roof of the tunnel; and, wherein the first and second walls are movable between respective first positions proximate respective walls of the tunnel and respective second positions spaced from the walls of the tunnel.
Features and advantages of the embodiments of the present application will become apparent from the following detailed description, taken in combination with the appended drawings, in which:
It will be noted that throughout the appended drawings, like features are identified by like reference numerals.
In the following description, details are set forth to provide an understanding of the application. In some instances, certain structures, techniques and methods have not been described or shown in detail in order not to obscure the application.
The rapid development canopy (or mobile canopy or mobile canopy system or rapid advance shield) 100 of the present application allows for safe and accelerated drift excavation, thereby accelerating mine construction and increasing value by reducing the time to first production. Reducing the cost or time of drift development may also reduce overall mining costs. The rapid development canopy system 100 of the present application is designed to increase development rates by improving utilization of the advancing tunnel face 1110. The canopy system 100 enables the execution of parallel excavation activities at the face 1110, with the development drill drilling the next round, while ground support is being installed behind. This reduces the development cycle time, thereby improving development productivity.
Thus, the mobile canopy system 100 may consist of three canopies (or shields) 110, 120, 130; two 110, 120 that provide temporary protection for the jumbo drill/operator, and the other 130 to support the back and wall areas of the tunnel 1100 for screening and bolting activities.
Advantageously, each of the canopies 110, 120, 130 is designed to be modular and easily assembled and disassembled. This is achieved by creating a modular and bolt together assembly that requires no field welding. The longest component of each canopy 110, 120, 130 is less than 12 feet in length so that all components may be transported in a standard cage to the drift 2 or tunnel face 1110.
According to one embodiment, each canopy, for example the face canopy 110, includes: a first or left side wall 113; a second or right side wall 114, the second wall 114 opposing and spaced from the first side wall 113; and, a roof 115 coupled (e.g., bolted, etc.) between and supported by the first and second side walls 113, 114.
Each of the canopies 110, 120, 130 may be custom designed to fit any drift size up to approximately 5 meters wide by approximately 5 meters high, for example. Each of the canopies 110, 120, 130 is designed to expand and collapse approximately 1 meter in both the horizontal and vertical directions for transport and to adjust to drift size. In order to achieve smooth contraction and expansion, the canopy system 100 incorporates rollers and rails on each post and rafter. The canopies 110, 120, 130 may be both lifted and expanded with cylinders or actuators (e.g., hydraulic cylinders or actuators) and respective control systems.
Referring to
According to one embodiment, the roof 115 includes a number (e.g., 8) of spaced and arched (or curved) rafters 300 that are coupled (e.g., bolted, etc.) at a first or left side to an upper end 202 of a respective post 200 of the first or left wall 113 and at a second or right side to an upper end 202 of a respective post 200 of the second or right wall 114. Each rafter 300 includes at least two arced (or curved) segments 310, 320, 330 that are slidably coupled by a respective rail 500 and roller mechanism. An actuator or hydraulic cylinder 870 may be used to horizontally expand and contract each rafter 300 by moving the rafter segments 310, 320, 330 away or toward each other. As such, the roof 115 may be horizontally expanded and contracted thus narrowing and widening the width (i.e., the spacing between the walls 113, 114) of the canopy 110 between expanded and contracted positions 605, 606. According to one alternate embodiment, the rafters 300 may be flat rather than arched or curved.
Referring to
According to one embodiment, each of the three canopies 110, 120, 130 is designed to withstand a dynamic load equivalent to a large rock burst and the required static load equivalent to or greater than standard rock support.
In operation, the mobile canopy system (or rapid advance shield system) 100 is assembled in a tunnel 1100 of a mine and the face canopy 110 is coupled to jumbo canopy 120 which is in turn coupled to the bolting canopy 130. The canopies 110, 120, 130 may be slide about in the tunnel 1110 on the skis 1010, 1020 mounted to the bottom of each canopy 110, 120, 130. The front end 111 of the face canopy 110 is then slide into position adjacent to the face 1110 of the tunnel 1100. Hydraulic cylinders (e.g., 270) mounted in the walls 113, 114 of each canopy (e.g., 110) are operated to extend the walls 113, 114 and hence raise the arched or curved roof (e.g., 115) of each canopy 110 into an extended position 605 proximate the roof 1120 of the tunnel 1100. In addition, hydraulic cylinders (e.g., 870) mounted in the roof 115 of each canopy 110 are operated to extend the roof 115 and push the walls 113, 114 of each canopy 110 into respective extended positions 601 proximate the walls 1130, 1140 of the tunnel 1110. The chain curtain 600 mounted over the front end 111 of the face canopy 110 may then be raised to allow mining operations to begin at the tunnel face 1110 by miners or operators safely positioned within 1300 the canopy 110. In the event that loose material is generated by the mining operations and falls onto the roof 115 of the canopy 110, operators within 1300 the canopy 110 may unlock and open the hinged roof panels 800 provided in the roof 115 to remove the loose material.
Thus, according to one embodiment, there is provided a mobile canopy (e.g., a face canopy) 110 for use in a tunnel 1100, comprising: first and second opposing and spaced walls 113, 114; a curved (or arched) roof 115 coupled between the first and second walls 113, 114; first and second skis 1010, 1020 mounted to respective bottoms (e.g., 201) of the first and second walls 113, 114, the skis 1010, 1020 adapted to slide the mobile canopy 110 about a floor 1150 of the tunnel 1100; wherein the curved roof 115 slopes downward from a front end 111 of the mobile canopy 110 toward a back end 112 of the mobile canopy 110, the front end 111 of the mobile canopy 110 for positioning adjacent to a face 1110 of the tunnel 1100; wherein the curved roof 115 is movable between a first position 605 proximate a roof 1120 of the tunnel 1100 and a second position 606 spaced from the roof 1120 of the tunnel 1100; and, wherein the first and second walls 113, 114 are movable between respective first positions 601 proximate respective walls 1130, 1140 of the tunnel 1100 and respective second positions 602 spaced from the walls 1130, 1140 of the tunnel 1100.
The above mobile canopy 110 may further include a curtain 600 mounted over a front end 111 of the canopy 110, the curtain 600 movable from an extended position 603 covering the front end 111 of the canopy 110 to a retracted position 604 uncovering the front end 110 of the canopy 110. The mobile canopy 110 may further include at least one actuator 270 mounted in each of the first and second walls 113, 114 and operable to extend and contract the first and second walls 113, 114 and hence move the roof 115 between the first position 601 proximate the roof 1120 of the tunnel 1100 and the second position 602 spaced from the roof 1120 of the tunnel 1100. The mobile canopy 110 may further include at least one actuator 870 mounted in the roof 115 and operable to extend and contract the roof 115 and hence move the first and second walls 113, 114 between the respective first positions 605 proximate the respective walls 1130, 1140 of the tunnel 1100 and the respective second positions 606 spaced from the walls 1130, 1140 of the tunnel 1100. The first and second walls 113, 114 may include one or more spaced vertical or approximately vertical studs 200. Each stud 200 may include a first segment 210 slidably coupled to a second segment 220 thereby allowing the first and second walls 113, 114 to be extended and contracted 601, 602. The roof 115 may include one or more spaced rafters 300. Each rafter 300 may include at least two curved segments 310, 320, 330 that are slidably coupled to each other thereby allowing the roof 115 to be extended and contracted 605, 606. The roof may include at least one hinged roof panel 800 openable from inside 1300 the canopy 110. And, the at least one hinged rood panel 800 may include at least one respective lock 900 for securing the at least one hinged roof panel 800 in a closed position 801.
According to another embodiment, there is provided a method (or process) for advancing a tunnel face 1110 in an underground mine, comprising: blasting the tunnel face 1110 with explosives; removing debris generated by the blasting from a heading 3 of the tunnel 1100; positioning a mobile canopy (e.g., a face canopy) 110 at or near the heading 3; drilling holes in the tunnel face 1110 and packing the holes with additional explosives; and, securing the tunnel 1100 from inside the mobile canopy 110; wherein the mobile canopy 110 includes: first and second opposing and spaced walls 113, 114; a curved (or arched) roof 115 coupled between the first and second walls 113, 114; first and second skis 1010, 1020 mounted to respective bottoms (e.g., 201) of the first and second walls 113, 114, the skis 1010, 1020 adapted to slide the mobile canopy 110 about a floor 1150 of the tunnel 1100; wherein the curved roof 115 slopes downward from a front end 111 of the mobile canopy 110 toward a back end 112 of the mobile canopy 110, the front end 111 of the mobile canopy 110 for positioning adjacent to the tunnel face 1110; wherein the curved roof 115 is movable between a first position 605 proximate a roof 1120 of the tunnel 1100 and a second position 606 spaced from the roof 1120 of the tunnel 1100; and, wherein the first and second walls 113, 114 are movable between respective first positions 601 proximate respective walls 1130, 1140 of the tunnel 1100 and respective second positions 602 spaced from the walls 1130, 1140 of the tunnel 1100.
In the above method, the mobile canopy 110 may further include a curtain 600 mounted over a front end 111 of the canopy 110, the curtain 600 movable from an extended position 603 covering the front end 111 of the canopy 110 to a retracted position 604 uncovering the front end 110 of the canopy 110. The mobile canopy 110 may further include at least one actuator 270 mounted in each of the first and second walls 113, 114 and operable to extend and contract the first and second walls 113, 114 and hence move the roof 115 between the first position 601 proximate the roof 1120 of the tunnel 1100 and the second position 602 spaced from the roof 1120 of the tunnel 1100. The mobile canopy 110 may further include at least one actuator 870 mounted in the roof 115 and operable to extend and contract the roof 115 and hence move the first and second walls 113, 114 between the respective first positions 605 proximate the respective walls 1130, 1140 of the tunnel 1100 and the respective second positions 606 spaced from the walls 1130, 1140 of the tunnel 1100. The first and second walls 113, 114 may include one or more spaced vertical or approximately vertical studs 200. Each stud 200 may include a first segment 210 slidably coupled to a second segment 220 thereby allowing the first and second walls 113, 114 to be extended and contracted 601, 602. The roof 115 may include one or more spaced rafters 300. Each rafter 300 may include at least two curved segments 310, 320, 330 that are slidably coupled to each other thereby allowing the roof 115 to be extended and contracted 605, 606. The roof may include at least one hinged roof panel 800 openable from inside 1300 the canopy 110. And, the at least one hinged rood panel 800 may include at least one respective lock 900 for securing the at least one hinged roof panel 800 in a closed position 801.
The embodiments of the application described above are intended to be examples only. Those skilled in this art will understand that various modifications of detail may be made to these embodiments, all of which come within the scope of the application.
This application claims priority from and the benefit of the filing date of U.S. Provisional Patent Application No. 62/409,366, filed Oct. 17, 2016, and the entire content of such application is incorporated herein by reference.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CA2017/000223 | 10/16/2017 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 62409366 | Oct 2016 | US |
