Drill and blast method and apparatus for the same

Abstract

Disclosed is a drill and blast method for advancing the tunnel face in a mine, which makes use of a mobile canopy. The mobile canopy having vertical supports connected to a frame that supports a shield. The mobile canopy allows for face production activities and ground support activities to occur simultaneously or near simultaneously. This allows for more rapid advancement of the tunnel face compared to traditional batch drill and blast techniques.

Claims

1. A mobile canopy for use in a mining process, said mobile canopy comprising at least a first covered structure and a second covered structure, wherein the first and second covered structures each comprise a plurality of vertical supports connected to an inverted u-shaped frame and at least one of the covered structures supports a shield extending over the u-shaped frame comprising mesh coverage that can be detached from the u-shaped frame and moved away from the u-shaped frame toward a roof of a tunnel from inside the u-shaped frame to be attached to walls and the roof of the tunnel.

2. The mobile canopy of claim 1, further comprising a third covered structure comprising a plurality of vertical supports connected to a frame that supports a shield comprising mesh coverage that can be detached from the u-shaped frame and moved away from the u-shaped frame from inside the u-shaped frame to be attached to walls and a roof of the tunnel.

3. The mobile canopy of claim 2, wherein wheels are provided on one or more of the vertical supports to allow the mobile canopy to move within the tunnel.

4. The mobile canopy of claim 2, wherein one or more of the vertical supports engage wheels, or rails provided within the tunnel, to move the mobile canopy.

5. The mobile canopy of claim 2, wherein of the covered structures comprises longitudinal supports that interconnect adjacent cross-members of the frame and the shields of the other two covered structures comprise mesh coverage.

6. The mobile canopy of claim 2, wherein at least two of the covered structures are linked.

7. The mobile canopy of claim 2, wherein the covered structures further comprises one or more wall shieldings to shield against rock displacements from the walls and a face of the tunnel.

8. The mobile canopy of claim 7, wherein wall shielding of one of the covered structures comprises longitudinal supports that interconnect adjacent vertical supports and the wall shielding of the other two covered structures comprise mesh coverage.

9. The mobile canopy of claim 1, wherein one or more of the plurality of vertical supports are adjustable to lengthen the support.

10. The mobile canopy of claim 9, wherein the one or more of the plurality of vertical supports are provided with hydraulics or pneumatics to adjust the height of the support.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) These and other features, aspects and advantages of the present invention will become better understood with regard to the following description and accompanying drawings wherein:

(2) FIG. 1 shows a mobile canopy according to an embodiment of the present invention positioned in a drift;

(3) FIG. 2 shows a mobile canopy according to an embodiment of the present invention; and

(4) FIG. 3 shows a mobile canopy according to an embodiment of the present invention

DESCRIPTION OF THE INVENTION

(5) The following description is of a preferred embodiment by way of example only and without limitation to the combination of features necessary for carrying the invention into effect.

(6) 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.

(7) For the purposes of this disclosure, the following terms will be used to refer to the various parts of the mine. The horizontal mining tunnel in which work is taking place and where workers are present will be referred to as the drift. The tunnel face is the part of the mine where advancement of 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.

(8) 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. Various machines have been developed to remove the broken rock and debris from the heading. Examples of such machines include, but are not limited to, those produced by Atlas Copco, Eimco, and Hggloader.

(9) Once the broken rock has been cleared from the heading, and the heading surveyed for potential unstable rock formations, a mobile canopy (1) can be brought into position in the drift (2) at or near the heading (3) (FIG. 1). The mobile canopy (1) will provide shelter for the workers underneath, so that face production and ground support activities can take place simultaneously or nearly simultaneously.

(10) Face production activities include drilling or boring holes in the tunnel face and packing the same with explosives. In some cases, the face production activities might also include forms of sampling to determine one or more characteristics of the rock structure.

(11) In the present batch drill-and-blast technique, 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 can 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.

(12) The ground support activities take place behind the mobile canopy, or in some embodiments, 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. In the present invention, 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.

(13) As shown in FIG. 2, the mobile canopy (1) of the present invention includes a covered structure comprising a plurality of vertical supports (10) connected to a frame (11) that supports a shield (12). In one embodiment, the mobile canopy (1) comprises at least two covered structures (5, 6), each covered structure comprising a plurality of vertical supports (10) connected to a frame (11) that supports a shield (12). In the embodiment shown in FIG. 3, three covered structures (5, 6, 61) are provided, each structure connected to its neighbour by interconnected rings (60).

(14) 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) should be 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).

(15) 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.

(16) 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).

(17) 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 FIG. 1, vertical supports (10) are provided on two of the four corners of one of the covered structures, and the back portion of the covered structure is supported by the vertical supports (10) of the second covered structure.

(18) 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) (FIG. 3). In one embodiment, the cross members (32) are arced to allow for rocks to roll off the shield (12) in the event a rock comes into contact with the shield (12). The various elements of the frame (11) are also preferably made from steel.

(19) In one preferred embodiment, 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). Examples, of such shielding material includes, but is not limited to, typically 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 FIG. 3, the shield (12) can comprise a plurality of longitudinal supports (63) in order to provide a more permanent form of protection and support.

(20) In order to provide added protection to the workers positioned under the mobile canopy (1), wall shielding (40) may be also 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 provided 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).

(21) 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) (FIG. 3). The covered structures (5,6,61) can be connected to allow each structure (5,6,61) to travel freely in the drift (2). Alternatively, the two structures (5,6) can be permanently connected, but hinged to allow each structure (5,6) to move independently from each other. For example, the structures (5,6) can be both permanently and releasably connected by interconnected rings (60), which are attached to the frame (11) of each structure (5,6,61).

(22) 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) 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 m4 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.

(23) 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.

(24) 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, it is contemplated that this structure might also have detachable shielding the can be used in ground support activities.

(25) The present invention has been described with regard to preferred embodiments. However, it will be obvious to persons skilled in the art that a number of variations and modifications can be made without departing from the scope of the invention as described herein.