Patent Application
20170130417
The present invention relates to a safety bund system to provide improved edge protection where a rock berm or safety bund is employed and relates particularly, although not exclusively, to such an edge protection safety bund system for a haulage road or ramp in an open-pit mine.
In open-pit mining large haul trucks and other vehicles are used to transport the ore from the bottom of the pit to the surface. A low incline haulage road is employed on the pit wall to enable the vehicles to travel up out and down into the pit. An important safety feature of the haulage road is the provision of a safety bund or rock berm to prevent vehicles from accidentally leaving the road, either due to driver inattention, poor visibility or brake failure. Such rock bunds are also employed along pit ramp edges. Typically a safety bund is employed that consists of dirt and rock piled along the edge of the haulage road or pit ramp. Government regulations typically require the safety bund to be at least half the height of the wheels of the largest mining machine on-site.
There are several disadvantages of rock bunds. There is always the danger that a fully-loaded runaway truck will simply ride up and over, or crash through, the rock bund when travelling at high speed. This is because the incline of the sides of the rock bund, as defined by the angle of repose of the dirt and rock used to make it, may be relatively shallow. There is a further disadvantage due to the fact that the rock bund occupies a substantial area along the edge of the road or ramp, which reduces the width of the road or ramp and/or increases the total width of the land that has to be set aside for the road or ramp. This represents ‘wasted’ space, which is economically valuable; if some of this wastage can be eliminated by reducing the footprint of the safety bund it will result in significant savings.
The present invention was developed with a view to providing an edge protection safety bund system that improves the effectiveness of a rock bund in an open-pit mine. Although the following description of the edge protection safety bund system will be given primarily with reference to its application in an open-pit mine, it will be apparent that it may also have wider applications.
References to prior art in this specification are provided for illustrative purposes only and are not to be taken as an admission that such prior art is part of the common general knowledge in Australia or elsewhere.
According to one aspect of the present invention there is provided an edge protection safety bund system for use in connection with a rock bund made of rock fill, the safety bund system comprising:
a bund module having a barrier wall and a base plate, the barrier wall extending substantially perpendicularly upwards from the base plate, and a support web extending at an angle from a rear face of the barrier wall to an upper surface of the base plate wherein, in use, when rock fill is dumped onto the rear of the bund module and allowed to flow back to its natural angle of repose behind the barrier wall it creates a rock bund with a front face formed by the barrier wall.
Preferably the bund module is one of a plurality of bund modules arranged side by side to form an extended barrier wall. Advantageously a plurality of the bund modules is connected together so that they effectively act together in the event of a heavy vehicle impact. Typically the bund modules are connected together with a flexible elongate member. Typically the flexible elongate member is a rope or cable provided along the rear face of the barrier wall. Preferably the barrier wall of each bund module is designed to overlap with the barrier wall of an adjacent module wherein, in use, the rock fill is inhibited from coming through any gaps between the modules. Preferably each vertical edge of the barrier wall is formed with an overlap region having rounded edges which mate with a matching overlap region on an adjacent module.
Advantageously the support web is wedge-shaped in transverse cross-section, with a narrowest point of the web being closest to the rear face of the barrier wall. Preferably the support web is provided with a gap between the web and the rear face of the barrier wall and the upper surface of the base plate.
Preferably the barrier wall, base plate and support web of each bund module is formed as a single integral structure, typically by moulding. Advantageously the bund module further comprises a substantially hollow shell, a front wall of the hollow shell forming a front face of the barrier wall. Preferably the substantially hollow shell is filled with a suitable filler material. Typically the shell of the bund module is manufactured from a suitably rigid moulded plastics material, for example, a rota-moulded thermoplastic material. Advantageously the plastics material is a brightly coloured, high-visibility plastics material.
Preferably the barrier wall of the bund module is designed to have a height at least as high as the axle height of the largest open pit haul truck.
Throughout the specification, unless the context requires otherwise, the word “comprise” or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers. Likewise the word “preferably” or variations such as “preferred”, will be understood to imply that a stated integer or group of integers is desirable but not essential to the working of the invention.
The nature of the invention will be better understood from the following detailed description of a specific embodiment of the edge protection safety bund system, given by way of example only, with reference to the accompanying drawings, in which:
A preferred embodiment of an edge protection safety bund system 10 in accordance with the invention for use in connection with a rock bund made of rock fill is illustrated in
Advantageously a plurality of the bund modules 12 is connected together so that they effectively act together as a unit in the event of a heavy vehicle impact. Typically the plurality of bund modules 12 is connected together with a flexible elongate member, such as a rope or cable 22, provided along the rear face of the barrier wall 14, as shown in
Preferably the barrier wall 14 of each bund module 12 is designed to overlap with the barrier wall 12 of an adjacent module 12 wherein, in use, the rock fill is inhibited from coming through any gaps between the modules 12. As can be seen in
Advantageously the support web 18 is wedge-shaped with a narrowest point of the web 18 being closest to the rear face of the barrier wall 14. Preferably the support web 18 is formed with a gap 26 between the web 18 and the rear face of the barrier wall 14 and the upper surface of the base plate 16. The reverse wedge shape of the support web 18 of each bund module 12, in conjunction with the gap 26 between the webbing and the rear face and base plate, will counteract any rotational forces on the bund module 12 generated by the weight of rock on the barrier wall 14 using frictional forces within the rock fill mass of the rock bund 20.
Preferably the barrier wall 14, base plate 16 and support web 18 of each module 12 are formed as a single integral structure, typically by moulding. Advantageously the bund module 12 further comprises a substantially hollow shell, a front wall of the hollow shell forming a front face of the barrier wall 14. The hollow shell is preferably filled with a suitable filler material. Typically the shell of the bund module is manufactured from a suitably rigid moulded plastics material, for example, a rota-moulded thermoplastic material. Advantageously the plastics material is a brightly coloured, high-visibility plastics material. The plastics material may also include internal steel (or other material) reinforcement. Preferably the filler material is a rigid fill media such as foamed grout or concrete. The bund modules 12 may also be manufactured entirely from concrete.
Preferably the barrier wall 14 of the bund modules 12 is designed to have a height at least as high as the axle height of the largest open pit haul truck.
The edge protection safety bund system 10 is designed to act as a cantilever wall to create more effective rock bunding along pit walls and pit ramp edges. The bund modules 12 will typically be positioned in a line adjacent to the edge of a pit wall or pit ramp. Once in position rock fill will be dumped onto the rear side of the bund modules and allowed to flow back to the natural angle of repose, creating rock bunds of sufficient height for the particular sites' requirements.
The completed wall of bund modules 12 with rock behind it will be a much more effective barrier for several reasons. Firstly the extended barrier wall 14 will be close to vertical up to a height above the axle height of the largest open pit dump truck. This will ensure that impact forces are imparted through the safety bund system 10 and into the rock horizontally. This contrasts with a normal rock bund which is angled at the natural angle of repose of the rock (not normally higher than 45°). In fact the apparent angle of a rock bund, when a truck is coming down a pit ramp and hitting the bund on an acute angle can be quite low, and therefore it is relatively easy for a large truck tyre to drive up the bund. This means that the rock has to do work on the underside of the truck as it goes over the rock bund. In the case of an acute angle collision the tyre will be deflected back into the ramp. With an impact closer to perpendicular to the line of the barrier wall 14, the bund modules 12 will work together and the truck will have to push the modules as a unit through the mass of rock. This means a much larger volume of rock has to be mobilised in order to allow the truck to push through the bund, than would otherwise be the case if it drove partially up or into a conventional rock bund.
A further benefit of the edge protection safety bund system 10 is that it will reduce the footprint required to provide sufficient edge protection for heavy equipment. This means mines can be redesigned to have narrower in pit ramps which results in potentially very significant economic benefits to the operation. One of the problems with rock bunds on open pit roads is that they can often be used as ‘borrow’ by grader operators working to maintain the road surface. This means the effective width of the rock bund can be eroded away over time without anyone noticing.
The use of high visibility bund modules 12 will result in users of the road feeling safer, and will better delineate roadways in times of low visibility such as night time or during foggy conditions.
Now that a preferred embodiment of the edge protection safety bund system has been described in detail, it will be apparent that the described embodiment provides a number of advantages over the prior art, including the following:
It will be readily apparent to persons skilled in the relevant arts that various modifications and improvements may be made to the foregoing embodiments, in addition to those already described, without departing from the basic inventive concepts of the present invention. For example, the shape and configuration of the bund module may depart significantly from that of the illustrated embodiment, without in any way altering the effective functioning of the module. Therefore, it will be appreciated that the scope of the invention is not limited to the specific embodiments described.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2014903228 | Aug 2014 | AU | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/AU2015/000378 | 6/30/2015 | WO | 00 |
