Haulage System for Hauling Goods along a Path

Field of the Invention

This invention relates to a haulage system for hauling goods along a path. In particular the invention relates to a haulage system for use in pit mining. The haulage system assists in the transport of material from the pit.

Background Art

The increasing depth and mining rates in new and developing open pit mining operations has led to the consideration of alternative options to the conventional removal of ore/waste from open pits. Currently, material is removed from the pit by diesel truck haulage. These vehicles travel along roadways typically incorporated along the pit walls, or by separate ramps into the pit. When designing these roadways, numerous factors, such as gradients and width, must be taken into consideration. As the pits increase in depth, the constraints, which dictate the design of the roadway, become increasingly difficult to meet.

Any type of trucking operation out of a pit results in considerable operating and maintenance expenses, high road maintenance, dust suppression problems, safety issues, the problem of congestion, particularly in tight conical pits, and the considerable time taken for a return journey. Furthermore, the truck haul roads into/out of the pit need to be sufficiently wide to accommodate two trucks passing in opposite direction of travel. These roads could be 30 metres wide - the wider the road, the flatter the overall slope of the pit wall must be in order to support the road. The flatter the slope of the pit wall, the greater the pit opening needs to be, requiring the removal of a greater amount of waste material before the ore can be accessed. This can make a significant difference to the economies of large deep pits.

Trucks do, however, provide flexibility and are needed at the operating face to collect rock from within the pit.

To date, the alternatives to a roadway system include the partial electrification of the haulage trucks using overhead conductors, in-pit crushing of ore/waste and the possibility of hoisting the ore up the slope of the pit.

The use of in pit crushers and conveyors also has inherent difficulties. At present the type of in-pit crusher suitable for crushing hard rock at run-of-pit size and with crushing rates of say 4000 tonnes per hour is a large gyratory type of crusher. Major disadvantages of the in-pit crushing/conveying systems include:

. installations are extremely heavy;

. high initial installation cost and subsequent relocation cost of the hard rock crusher and conveyors;

. high wear on a series of very large and long conveyor belts, particularly by dense and very sharp rocks, resulting in high maintenance and belt replacement costs;

. susceptibility of in-pit crushers and conveyors to damage from blasting;

. high operating costs caused by crushing all the waste;

. batching of ore and waste crushing and conveying with resulting pit scheduling problems;

. redesign of the pit layout necessary to accommodate the conveyors. This results in a greater strip ratio and overpass or underpass systems to allow conveyors to cross haul roads, or diversion of the haul roads.

Several systems have also been proposed whereby a counter balanced carrier traverses directly up the pit wall. These systems, however, require substantial infrastructure to be positioned adjacent the rim of the pit opening, and may compromise the integrity of the pit's rim. Furthermore these systems do not address the issues which relate to changes in gradient of the pit wall. One of these systems is disclosed in WO 99/05396 Dames & Moore Pty Ltd.

The preceding discussion of the background to the invention is intended only to facilitate an understanding of the present invention. It should be appreciated that the discussion is not an acknowledgment or admission that any of the material referred to was part of the common general knowledge as at the priority date of this application.

It is an object of the present invention to provide an alternative pit haulage system which overcomes one or more of the disadvantages of the prior art or provides an alternative to the prior art.

Disclosure of Invention

The present invention has been designed for use with the haulage system described in WO 2006/024097 to the current applicant, GHD Pty Ltd. However, it is to be understood that the present invention can be utilised in any system in which a track extends across terrain having variations in gradient.

It is also an object of the present invention to provide a haulage system for hauling goods along a path whereby a support surface upon which goods are placed remains in a predetermined orientation, such as horizontal, regardless of changes in path profile.

The present invention provides a haulage system for hauling goods along a path extending between a first position and a second position between which the profile of the path varies, the haulage system comprises:

at least one carrier comprising a support surface pivotally connected to a frame, the support surface being adapted to support the goods;

at least one track assembly extending between the first position and second position and adapted to guide and support the at least one carrier, the track assembly at least comprising a first track and a second track, the second track being in a spaced relation from the first track,

whereby the first track is adapted to support the carrier as it moves along a first path profile of the path, whereupon approaching a second path profile a portion of the carrier engages the second track causing the support surface to pivot such that the support surface remains in a predetermined orientation.

The profile of the path may vary in that it incorporates two or more gradients, and/or incorporates a step or other discontinuation in the path.

The carrier may comprise a first set of wheels and a second set of wheels. The first set of wheels may be adapted to remain in engagement with the first track. The second set of wheels may be adapted to engage the second track as the carrier approaches the second path profile.

The first set of wheels may be attached to the frame.

The second set of wheels may be attached to the support surface.

The second set of wheels may extend further from the centre of the support surface than the first set of wheels.

The second track extends substantially along that part of the path having the second path profile. The second track may comprise a transition portion located adjacent that point along the path in which the first path profile and second path profile meet.

The first track may be in the form of a set of first rails and the second track may be in the form of a set of second rails.

The first set of wheels may comprise a rear frame set of bogies and a forward frame set of bogies which run along the first set of rails.

The second set of wheels may comprise a support surface set of bogies which run along the second set of rails.

The second set of rails may extend parallel to the first set of rails. The first set of rails may be positioned inside and adjacent to the second set of rails and extend along the extent of the path. The second set of rails may be in an elevated position relative to the first set of rails. The elevation and angle of the second set of rails will be orientated to ensure the support surface remains in the predetermined orientation.

The at least one carrier may be adapted to haul cargo or support and convey a vehicle such as a truck.

Preferably the path extends along a sloping surface.

There may be two carriers and two track assemblies whereby the carriers move simultaneously but in opposite directions such that one carrier counter-balances the other carrier.

Whilst the above summary is directed to a path having two path profiles the scope of this invention incorporates those slopes having more than two profiles. The modifications to the above invention to accommodate further profiles being obvious to a person skilled in the art.

The present invention further provides a haulage system for hauling vehicles along a path extending between a first level and a second level of a mining pit between which the gradient of the path varies, the haulage system comprises:

at least one carrier adapted to support and convey a vehicle such as a truck whereby the support upon which the vehicle is upon can pivot relative to a frame of the carrier;

at least one loading platform located at the first level, and at least one dispatch platform located at the second level;

at least one track assembly extending between said dispatch platform and said loading platform and adapted to guide and support the at least one

carrier, the track assembly at least comprising a first track and a second track, the second track being parallel to but in a spaced relation from the first track, whereby the first track is adapted to support the carrier as it moves along a first gradient of the pit wall, whereupon approaching a second gradient a portion of the carrier engages the second track causing the support upon which the vehicle is upon to pivot such that the support remains in a substantially horizontal orientation;

at least one sheave means located below the dispatch platform;

a hauling means comprising at least one winder fixedly disposed away from the pit wall, and

a cable means attached between the at least one winder and the at least one carrier, the cable means being supported by the sheave means;

whereby a truck laden with ore is received upon the at least one carrier via the loading platform, the winder is activated to haul the at least one carrier up the track until the carrier reaches the dispatch platform whereupon the truck drives off the at least one carrier on to the dispatch platform, the support upon which the vehicle is upon remaining in a substantially horizontal orientation as the vehicle is hauled along the at least one track assembly.

Preferably, the first track and second track are in the form of a set of rails.

Preferably the track assembly extends below the loading platform a sufficient distance such that the support member of the carrier aligns with the top of the loading platform when the carrier is at a lower most position, wherein the truck may be received thereupon.

Preferably the track assembly extends to the top of the pit wall such that the support member of the carrier aligns with the dispatch platform when the carrier is at an upper most position, wherein the truck may drive off the carrier.

Preferably the hauling system comprises a first carrier and a second carrier, each being associated with its own track assembly, sheave means, winder, and cable means, which is in the form of a cable.

The present invention further provides a haulage system for hauling vehicles along a path extending between a first level and a second level of a mining pit between which the gradient of the path varies, the haulage system comprises a loading platform located at the first level, and a dispatch platform located at the second level, the haulage system also comprises a first hauling apparatus and a second hauling apparatus, each hauling apparatus comprising:

a carrier adapted to support and convey a vehicle such as a truck whereby the support upon which the vehicle is upon can pivot relative to a frame of the carrier;

a track assembly extending between said dispatch platform and said loading platform and adapted to guide and support the carrier, the track assembly at least comprising a first track and a second track, the second track being parallel to but in a spaced relation from the first track, whereby the first track is adapted to support the carrier as it moves along a first gradient of the pit wall, whereupon approaching a second gradient a portion of the carrier engages the second track causing the support upon which the vehicle is upon to pivot such that the support remains in a substantially horizontal orientation;

a sheave located below the dispatch platform;

a hauling means comprising a winder fixedly disposed at the top of the pit at a distance from the pit's rim, and

a cable means attached between the winder and the carrier via the sheave

whereby the first hauling apparatus and second hauling apparatus counterbalance each other and work in opposed fashion such that as the

carrier of one apparatus ascends its respective track assembly and reaches the dispatch platform, the carrier of the other apparatus simultaneously descends its respective track assembly and reaches the loading platform during which each support upon which the vehicle is upon remains in a substantially horizontal orientation as each carrier is hauled over the different gradients the respective track assembly passes over.

In accordance with a further aspect of the present invention there is provided a method for conveying material excavated from within a pit mine to the outer peripheral surface of the mine across the wall of the pit, which has at least one change in gradient, the method including:

loading a truck disposed within the pit with excavated material from within the pit, and positioning it via a loading platform onto a carrier, the carrier having a surface upon which the truck is supported;

hauling said carrier supporting said truck along a first track extending along a first gradient of the pit wall until the carrier approaches a second gradient;

hauling said carrier along a transition portion whereby a portion of a support surface of the carrier engages a second track which is in spaced relation to the first track, upon engaging the second track the surface of the carrier pivots with respect to a frame of the carrier such that the support surface remains substantially horizontal;

hauling said carrier supporting said truck along the second track extending along the second gradient of the pit wall until the carrier approaches a dispatch platform;

dispatching said truck from the carrier when the carrier aligns with the dispatch platform at the top of said pit;

loading another truck onto the carrier; and

returning the further truck to the loading platform along said first and second tracks.

The method may further comprise the step of positioning an empty truck via the dispatch platform onto a further carrier at the same time as positioning the loaded truck via the loading platform onto the carrier, whereby the carriers are operatively connected such that as the loaded truck ascends the first and second tracks, the further carrier and empty truck descends another set of first and second tracks, and hence acts as a counter-balance.

Brief Description of Drawings

The invention will be better understood in light of the following description of one specific embodiment thereof. The description is made with reference to the accompanying drawings, wherein:

Fig 1 is a schematic side view of a carrier of a haulage system moving along a first gradient, according to an embodiment of the present invention;

Figure 2 is a view similar to figure 1 however now travelling over a second gradient;

Figure 3 is a modelled perspective view of figure 1 ;

Figure 4 is a modelled perspective view of figure 2;

Figure 5 is a schematic plan of the rim and top portion of a pit employing a haulage system according to an embodiment of the present invention; and

Figure 6 is a side view of a carrier of the haulage system supporting a truck located at a dispatch platform.

Best Mode(s) for Carrying Out the Invention

Whilst the present invention can be used for any system in which an item is to be hauled between a first position and a second position across a path having multiple changes in path profile, the present embodiment of the invention is directed towards a haulage system 11 for use in the mining industry. In particular the embodiment is directed towards a haulage system 11 disposed at one side of an open pit mine, and a method for conveying material excavated from within the pit mine (first position) to the outer peripheral surface thereof (second position) using the haulage system 11. With reference to the figures, the open pit mine comprises a pit floor, a pit wall 17 and a pit rim located around the periphery of the pit opening.

The characteristic of the pit wall 17 in this embodiment necessitates that the path along which material is to be hauled has a first path profile in the form of a first section commencing from the pit floor and being of a steep gradient, and a second path profile in the form of a second section travelling along a second, less severe gradient and terminating at the rim of the pit.

Referring to figure 5, the haulage system 11 generally comprises a first hauling apparatus 21a and a second hauling apparatus 21 b, a dispatch platform 22 adjacent the pits rim, a loading platform located on the pit floor, and hauling means 23.

The hauling means 23 comprises a double drum winder 24 disposed a distance from the pit's rim. The first hauling apparatus 21a and second hauling apparatus 21 b are in side-by-side relation.

Each hauling apparatus 21a, 21b comprises a carrier 29 positioned upon and movable with respect to a track assembly 31 , the track assembly 31 spanning across the path the carrier 29 is to traverse.

The track assembly 31 is in the form of a first track 111 and a second track 113, each in the form of a set of rails. Along the second section of the path, the rails of

the first track 111 are placed parallel to and within the rails of the second track 113 whereby the second track 113 is in an elevated position relative to the first track 111 , as best shown in figure 4. The degree of elevation of the second track 113 is governed by the second gradient of the path.

The first track 111 extends between the dispatch platform and loading platform, and is adapted to fully support and guide the carrier 29 over the first section of the path. The second track 113 commences at the junction of the first gradient and second gradient and continues to the dispatch platform. The second track also incorporates a transition portion (not shown) located adjacent that point along the path in which the first gradient and second gradient meet. In an embodiment this transition portion is in the form of a slope extending from the pit wall 17 to the required position of the second track. The second track 113 support and guides a portion of the carrier 29 over the second section of the path, whilst the first track 111 support and guides the other portion of the carrier 29 over the second section of the path as will be described below.

Referring to figure 1 and 2, each carrier 29 comprises a flat support surface 30 adapted to receive and support a truck and a truck stop 32 adapted to prevent the truck from rolling off the support surface 30.. The support surface 30 is pivotally mounted to a frame 115 of the carrier.

The carrier 29 comprises a first set of wheels 117 attached to the frame 115 and a second set of wheels 127 attached to the support surface 30. The first set of wheels 117 engage the rails of the first track 111. The second set of wheels 127 engage the rails of second track 113 as the carrier 29 approaches the second gradient. The second set of wheels extend further from the centre of the carrier 29 than the first set of wheels as the set of rails of the second track 113 are spaced wider than the rails of the first track 111.

The first set of wheels 117 comprise a rear frame set of bogies 117a and a forward frame set of bogies 117b. The second set of wheels 127 comprises a support surface set of bogies 127a. That is to say the support surface set of

bogies 127a is connected to the support surface. This may be directly or indirectly.

During the hauling process the configuration of the carrier 29 and track assembly 31 ensure the support surface 30 of the carrier 29 remains in a substantially horizontal orientation. As the carrier 29 travels along the first track 111 only the first set of wheels 117 engage the first track 111. As the carrier 29 approaches the second gradient of the path the second set of wheels 127 engage the transition portion of the second track 113 before travelling along the second track 113. This causes the support surface 30 to pivot with respect to the frame 115 about pivot point 51. The second set of wheels 127 remain in contact with the second track 113 along the extent of the second gradient, whilst the first set of wheels 117 remains in contact with the first track 111 to support the frame 115. Obviously the reverse process takes place as the carrier 29 descends along the track assembly 31. The configuration of the first track 111 and second track 113, coupled with the support member 30 being pivotally mounted to the frame 115 of the carrier 29, ensures that the support surface 30 remains in a substantially horizontal orientation by accommodating the variances in gradient.

Each hauling apparatus 21 further comprises cable means 33 extending from the carrier 29 to the drum winder 24.

In the present embodiment, the configuration of the haulage system 11 allow the pair of carriers 29 to operate in balance. That is, each carrier 29 is connected to one end of a respective cable means 33, whilst the other end of the respective cable means 33 is connected to the respective side of the winder drum 24, with the cable means 33 associated with the first haulage apparatus 21a being wound around the wind drum 24a in an opposite direction to cable means 33 of the second hauling apparatus 21 b.

When one side of the drum winder is wound to one extreme, the carrier 29 of the first hauling apparatus 21a is disposed at the dispatch platform 22, allowing a fully laden truck to drive off the carrier 29 before another empty truck boards the carrier 29. As this occurs, the carrier 29 of the second hauling apparatus 21 b is

simultaneously disposed at the loading platform for unloading an empty truck and allowing a fully laden truck to drive onto the carrier 29.

When the drum winder 24 is wound to the other extreme, the position of the carriers 29 are reversed. In this manner, the winder is always under a consistent load from a fully laden truck on one carrier 29 and an empty truck on the other carrier 29. The carrier 29 of one hauling apparatus 21 counter-balances, to a degree, the carrier 29 of the other hauling apparatus, and hence the hauling system 11 is only required to move an effective weight of the pay load contained in the ascending laden truck.

The automatic haulage system 11 of the present invention presents major advantages, particularly in those instances where an object is required to be hauled across a railway extending along a path of varying gradients.

It should be appreciated that the scope of the present invention is not limited to the specific embodiment described herein. Accordingly, changes and modifications to the embodiment that are in accordance with standard engineering design and which do not depart from the spirit of the invention are considered to fall within the scope of the invention.

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.