Field of the Invention

The present invention relates to a conveyor system suspended from a rope and relates particularly, though not exclusively, to such a conveyor system employed in the mining industry.

Background to the Invention

In the mining industry belt conveyors are used extensively for transporting ores and other materials over relatively short distances and/or over difficult terrain. They are also used for loading ore and other materials into transport containers, such as rail cars, etc. A conventional belt conveyor typically comprises an endless conveyor belt which is looped about two or more drums or pulleys, including at least one powered drum which drives the belt. The belt is supported along its length by a plurality of rollers, idlers or other support surfaces, which help to carry the weight of the ore or other material. One of the limitations of conventional belt conveyor systems is that the angle of inclination of the conveyor belt is limited to about 18° before the ore or material will begins to slide on the belt, which can lead to catastrophic failure and excessive spillage. Therefore this type of belt conveyor system is not suitable for transporting material over steep inclines, for example, from the bottom of an open-cut mine to the top of the pit.

One kind of prior art belt conveyor system that has been developed for steep inclines is a pipe conveyor. In a pipe conveyor system the conveyor belt is formed by support rollers into a pipe, and this pipe is then supported in a ring of rollers provided at spaced intervals along the length of the conveyor. At the discharge point the pipe is unfolded and travels in an open, flattened condition during the return loop.

Another kind of prior art belt conveyor system that has been developed for transporting material over difficult terrain is a rope conveyor, for example, of the kind developed by Doppelmayr Transport Technology. In a rope conveyor the belt is supported on a rope and there is no need for any rollers or other support surface, as the full weight of the material on the conveyor belt is carried by the rope. US 6,588,583 describes such a prior art rope conveyor system in which two pairs of supporting cables are arranged and anchored, one above the other, by means of a plurality of support frames. A conveyor belt can be moved along and is supported by two supporting cables on respective rollers, provided at the ends of a plurality of supporting axles provided at spaced intervals along the belt. The belt is attached to the undersides of the supporting axles. Corrugated side walls are provided on each side of the belt. There are several disadvantages of this particular rope conveyor design. One disadvantage in some situations is that the conveyor belt has an open layout, which again limits the maximum angle of inclination of the belt. The present invention was developed with a view to providing a new kind of rope conveyor system that can be used for transporting materials over difficult terrain, to enclose the transported material and which can handle steeper angles of inclination than prior art systems.

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.

Summary of the Invention

According to one aspect of the present invention there is provided a rope conveyor system comprising: a conveyor belt suspended from a flexible elongate member, the conveyor belt having a pair of carry rollers provided on respective first and second edges of the conveyor belt for rolling engagement with the flexible elongate member wherein, in use, when the conveyor belt is suspended from the flexible elongate member the belt assumes a partially-enclosed curved shape when viewed in cross-section. Advantageously when the belt assumes such a partially-enclosed 'water- drop' shape it will apply pressure to any enclosed material and provide additional resistance against sliding movement of the material.

Preferably the flexible elongate member is one of a plurality of flexible elongate members. Typically first and second flexible elongate members are provided and the pair of carry rollers respectively engages with the first and second flexible elongate members. Preferably the pair of carry rollers is one a plurality of pairs of carry rollers provided at spaced intervals throughout the length of the conveyor belt. Typically the plurality of flexible elongate members is supported in a stabiliser frame, which maintains a constant distance between the first and second flexible elongate members and also distributes forces transferred to the flexible elongate members from the carry rollers.

Preferably the flexible elongate members are suspended between first and second anchor points, so as to form a catenary shape between the anchor points.

Preferably each carry roller is rotatably mounted on a support arm attached to the belt edge and is adapted to facilitate transfer of normal forces from the belt to the carry roller, and limited bending moments to the carry roller wherein, in use, any horizontal loads on the carry rollers are minimised.

Typically the support arm comprises an elongate portion on which the carry roller is rotatably mounted at one end, the elongate portion having an elbow which is adapted to allow a plane of rotation of the carry roller to be substantially aligned with a plane of the edge of the belt. Typically the support arm further comprises a mounting plate wherein, in use, the mounting plate is attached to the edge of the belt, and the other end of the elongate portion of the support arm is attached to the mounting plate.

In one embodiment the belt comprises plurality of flexible elongate loops integrated into the conveyor belt material, extending laterally of the belt at spaced intervals along its length, to provide lateral reinforcement for the belt, and also protrude from the edges of the belt to provide connection points for the belt. Advantageously the mounting plate of the support is provided with a semicircular-shaped loop retaining groove, on which one of the flexible elongate loops is received. Preferably a restraining cover plate slides over the retaining groove, and is retained on the mounting plate to restrain the steel rope loop in the retaining groove. Advantageously a locking bolt locks the cover plate onto the support arm.

Advantageously the rope conveyor system further comprises first and second sealing skirts provided along the respective edges of the conveyor belt wherein, in use, when the belt assumes a partially-enclosed curved shape in cross-section the sealing skirts overlap so as to substantially enclose the material within the conveyor belt.

Preferably third and fourth flexible elongate members are provided, a spaced below the first and second flexible elongate members, from which the conveyor belt is suspended on the carry rollers during its return journey. During its return journey the conveyor belt is turned inside out and assumes an open U-shape in cross-section.

According to another aspect of the present invention there is provided a conveyor system comprising: a conveyor belt suspended from an elongate member, the conveyor belt having a pair of carry rollers provided on respective first and second edges of the conveyor belt for rolling engagement with the elongate member wherein, in use, when the conveyor belt is suspended from the elongate member the belt assumes a partially-enclosed curved shape when viewed in cross- section.

Preferably the elongate member is one of a plurality of elongate members. Typically first and second elongate members are provided and the pair of carry rollers respectively engages with the first and second elongate members. Preferably the pair of carry rollers is one a plurality of pairs of carry rollers provided at spaced intervals throughout the length of the conveyor belt.

In one embodiment the plurality of elongate members is a plurality of substantially rigid elongate members, and is supported on roof mounted support frames located at spaced intervals along an underground tunnel roof, which support the belt in both its carry and return journeys.

According to a further aspect of the present invention there is provided a wharf conveyor system for loading ships offshore, the conveyor system comprising: a conveyor belt suspended from a flexible elongate member; a plurality of stabiliser frames in which the flexible elongate member and the conveyor belt is supported in a stable manner in both its carry and return journeys; and, a plurality of support columns located at suitable spaced intervals in the seabed, each support column supporting one of the plurality of stabiliser frames; wherein, in use, materials can be conveyed to an offshore ship via the conveyor belt.

Preferably the flexible elongate member is one of a pair of flexible elongate members, and the conveyor belt has a pair of carry rollers provided on respective first and second edges of the conveyor belt for rolling engagement with the respective flexible elongate members. Typically third and fourth flexible elongate members are also supported on the stabiliser frame, spaced below the first and second flexible elongate members, from which the conveyor belt is suspended on the carry rollers during its return journey, and wherein during its return journey the conveyor belt is turned inside out and upside down, so as to assume an open U-shape in cross-section. Advantageously a distance between the third and fourth flexible elongate members for the return belt support rollers is increased so that in the event of spillage any spilled material will be collected by the return belt.

According to a still further aspect of the present invention there is provided a cross-pit spreader or conveyor bridge system for conveying ore from a mine pit to a dump area, the system comprising: a conveyor belt suspended from a flexible elongate member; and, first and second mobile machines for supporting each end of the flexible elongate member, each mobile machine being heavy enough to transfer horizontal tension forces from the elongate member via friction into the ground.

Preferably each mobile machine is supported by a crawler. Advantageously each crawler is provided with a hydraulically operated claw system, mounted on an underside of a crawler chassis to increase a ground friction factor. In one embodiment a first one of the mobile machines located in the mine pit comprises a receiving boom pivotally mounted on a receiving boom slew deck, and wherein the slew deck is supported on a conveyor slew frame which is mounted on the first mobile machine.

Typically the flexible elongate member is one of a pair of flexible elongate members, and the conveyor belt has a pair of carry rollers provided on respective first and second edges of the conveyor belt for rolling engagement with the respective flexible elongate members.

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 word "rope" will be understood to include any suitable flexible elongate member, from which a conveyor system can be suspended, including cables, steel hawsers, and rope made from wire or composite materials, etc. A rope typically comprises a plurality of fibres or strands of material that are twisted or braided together into a single strand.

Brief Description of the Drawings

The nature of the invention will be better understood from the following detailed description of several specific embodiments of the rope conveyor system, given by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a cut-away perspective view of a first embodiment of a rope conveyor system according to the present invention;

Figure 2 is an end elevation cross-section view of the rope conveyor system of Figure 1 ; Figure 3 is a perspective view of the rope conveyor system of Figure 1 shown in situ in an open-cut mine viewed from the bottom of a pit;

Figure 4 is a perspective view of the rope conveyor system of Figure 3 shown in situ in an open-cut mine viewed from the top of the pit;

Figure 5 is an enlargement of the top half of the rope conveyor system as shown in Figure 2;

Figure 6 is a top perspective view of the rope conveyor system of Figure 1 showing how a carry roller arm is attached to the edge of the belt;

Figure 7 is a top perspective view of the rope conveyor system of Figure 3 showing a loading station at the bottom end of the conveyor system; Figure 8 is an enlargement of a return drum for the conveyor belt at the bottom end of the conveyor system of Figure 7;

Figure 9 is an enlarged side perspective view of the superstructure below the loading station of the conveyor system of Figure 7; Figure 10 is an enlarged top perspective view of the loading station of the conveyor system of Figure 7;

Figure 1 is a top plan view of the rope conveyor system of Figure 10 showing a transition zone at the exit of the loading station; Figure 12 illustrates how a carry roller is engaged with the suspension rope from a guiding bar in the transition zone;

Figure 13 is an enlarged top perspective view of the transition zone in the rope conveyor system of Figure 10;

Figure 14 is another top perspective view of the transition zone in the rope conveyor system of Figure 10;

Figure 15 is a side perspective view of the bottom end of the rope conveyor system of Figure 3 showing the return drum for the belt;

Figure 16 is a perspective cut-away view of a second embodiment of a rope conveyor system according to the present invention; Figure 17 is an end elevation cross-section view of the rope conveyor system of Figure 16;

Figure 18 is an enlarged, cut-away perspective view of the top half of the rope conveyor system of Figure 16;

Figure 19 is an enlargement of the top half of the rope conveyor system as shown in Figure 17;

Figure 20 is a perspective cut-away view of the rope conveyor system of Figure 1 showing a preferred embodiment of a lift-off protection system;

Figure 21 is an end elevation cross-section view of the rope conveyor system of Figure 20; Figure 22 is a side perspective view of a third embodiment of a rope conveyor system according to the present invention;

Figure 23 is an enlarged side perspective view of rope conveyor system of Figure 22 showing how material is discharged from the conveyor belt; Figure 24 is a different side perspective view of the rope conveyor system as shown in Figure 22;

Figure 25 is an enlarged side perspective view of rope conveyor system of Figure 24 showing how material is discharged from the conveyor belt; Figure 26 is a partial cut-away view of a different embodiment of a conveyor belt used in the rope conveyor system of Figure 1 ;

Figure 27 is a top perspective view of a different embodiment of a mechanical arrangement for attaching a carry roller arm to the edge of the belt shown in Figure 26 in the rope conveyor system of Figure ; Figure 28 is a top perspective view of the rope conveyor system as illustrated in Figure 1 used as a cross-pit spreader;

Figure 29 is an enlargement of part of the cross-pit spreader of Figure 28 at the mine face side;

Figure 30 is an enlargement of a second part of the cross-pit spreader of Figure 28 on the dump area side;

Figure 31 is a perspective view of another embodiment of a rope conveyor system according to the present invention in the form of a port rope conveyor system;

Figure 32 is an end elevation cross-section view of the port rope conveyor system of Figure 3 ;

Figure 33 is a cut-away perspective view of the port rope conveyor system of Figure 31 ;

Figure 34 is top perspective view of a top of one of the support columns in the port rope conveyor system of Figure 31 ; Figure 35 is a perspective view of a still further embodiment of a rope conveyor system according to the present invention in the form of an underground conveyor system; and,

Figure 36 is cut-away perspective view of the underground conveyor system of Figure 35. Detailed Description of Preferred Embodiments

A first embodiment of a rope conveyor system 10 in accordance with the invention, as illustrated in Figures 1 to 15, comprises a conveyor belt 12 suspended from a flexible elongate member 14. The conveyor belt 12 has a pair of carry rollers 16a and 16b provided on respective first and second edges of the conveyor belt 12 for rolling engagement with the flexible elongate member 14. In use, when the conveyor belt 12 is loaded with material 18 and is suspended from the flexible elongate member 14, the belt 12 assumes a partially-enclosed curved shape in cross-section, as illustrated in Figures 1 , 2 and 5.

Advantageously when the belt 12 is filled with material 18, and it assumes such a partially-enclosed curved or 'water-drop' shape, it will apply pressure to the enclosed material 18 and thus provide additional resistance against sliding movement of the material. The enclosed belt configuration allows for high capacity conveying of material over steep inclines, typically up to 30° to 40° to the horizontal. A possible application of the rope conveyor system 10, for conveying ore out of an open-cut mine, is illustrated in Figures 3 and 4. This typically involves transporting the ore over a steep incline.

Preferably the flexible elongate member 14 is one of a plurality of elongate flexible members provided in the rope conveyor system 10. Typically first and second flexible elongate members 14a and 14b are provided and the pair of carry rollers 16a and 16b respectively engages with the first and second flexible elongate members 14a and 14b. Preferably the pair of carry rollers 16 is one a plurality of pairs of carry rollers 16 provided at spaced intervals throughout the length of the conveyor belt 12.

In the illustrated embodiment the flexible elongate members are steel suspension ropes or cables 14. Typically the plurality of flexible elongate members 14 is supported in a stabiliser frame 20, which maintains a constant distance between the first and second flexible elongate members 14a and 14b, and also distributes forces transferred to the flexible elongate members 14 from the carry rollers 16. Preferably the first and second flexible elongate members 14a and 14b are supported in the stabiliser frame 20 in relatively close proximity. More preferably, the first and second flexible elongate members 14a and 14b are supported in the stabiliser frame 20 in sufficiently close proximity that the carry rollers 16 overlap when the conveyor system 10 is viewed end-on, as can be clearly seen for example in Figures 2 and 5. This overlapping configuration of the carry rollers 16 ensures that the belt 12 assumes a partially-enclosed curved or "water drop" shape in cross-section when filled with material 18.

Advantageously third and fourth flexible elongate members 14c and 14d are also supported on the stabiliser frame 20, spaced below the first and second flexible elongate members 14a and 14b, from which the conveyor belt 12 is suspended on the carry rollers 16 during its return journey. During its return journey the conveyor belt is turned inside out and upside down, and typically assumes an open U-shape in cross-section, as shown in Figures 1 and 2. Preferably the stabiliser frame 20 also supports one or two flexible elongate members 24 for supporting a maintenance trolley (not shown). The maintenance trolley has similar carry rollers that can roll on one of the flexible elongate members 24, so that maintenance personnel can inspect, perform repairs or periodic maintenance on the rope conveyor system 10. The trolley support ropes 24 also provide additional stability for the rope conveyor system 10.

Typically conventional cableway ropes are used as suspension ropes 14. The main function of the suspension ropes 14 is to provide a track for the carry rollers 16 and to transfer the loads to the conveyor foundation points. In total seven ropes 14 are proposed to be used, four main suspension ropes 14, two maintenance trolley support ropes 24 and one maintenance trolley rope. The stabiliser frame 20 provides more stability during high wind conditions as well as to ensure a constant distance is maintained between the conveyor belt 12 during its carry and return journeys. Additional hold- down rollers (not illustrated) may be installed on the stabiliser frame 20 to avoid derailing under any operating conditions. Preferably the suspension ropes 14 are suspended between first and second anchor points 50, and form a catenary shape between the anchor points. The anchor points 50 will be described in more detail below.

Preferably each carry roller 16 is rotatably mounted on a support arm 22 attached to the belt edge and is adapted to facilitate transfer of normal forces from the belt 12 to the carry roller 16, and limited bending moments to the carry roller 16 wherein, in use, any horizontal loads on the carry rollers are minimised. Depending on the extent of material filling the belt 12 the inclination of the carry roller support arms 22 will adjust to provide for a vertical loading of the carry rollers 16.

As can be seen most clearly in Figure 5, each support arm 22 comprises an elongate portion 26, on which the carry roller 16 is rotatably mounted at one end. The elongate portion 26 has an elbow which is adapted to allow a plane of rotation of the carry roller 16 to be substantially aligned with a plane of the edge of the belt 12. Typically the support arm 22 further comprises a mounting plate 28 wherein, in use, the mounting plate 28 is attached to the edge of the belt 12 and the other end of the elongate portion 26 of the support arm 22 is attached to the mounting plate 28, with suitable fasteners, e.g. bolts, etc. Each pair of carry rollers 16a and 16b are offset with respect to each other to avoid contact under any operating conditions. The split design of the carry roller support arms 22 facilitates quick change-out of damaged carry rollers, if necessary. The carry rollers 16 are manufactured from a lightweight plastics material, and designed with a suitable bearing arrangement. The spacing of the suspension ropes 14 is used to restrict any carry roller derailment; however this spacing still allows for adjustment of the angle of inclination of the carry roller support arms 22, according to the degree of conveyor filling.

The conveyor belt 12 is of a conventional design similar to most conventional conveyors in operation. Reinforced conveyor belt edges will allow the transfer of the forces to the connection points for the support arms 22 via mounting plates 28. Conveyor belt stiffness normal to the conveyor moving direction is designed to be low to allow the formation of the water-drop shape (partially- enclosed curved shape in cross-section).

An alternative embodiment of conveyor belt 82 is illustrated in Figures 26 and 27, and comprises flexible elongate loops 84, e.g. 4mm steel rope, integrated into the conveyor belt material, extending laterally of the belt 82 at spaced intervals along its length. The steel rope loops 84 provide lateral reinforcement for the belt, and also protrude from the edges of the belt 82 to provide connection points for the belt. Steel reinforcing cords 86, e.g. 7mm steel cord, extending longitudinally of the belt 82 are also integrated into the belt material, and provide longitudinal reinforcement. The steel rope loops 84 pass laterally around the outside of the longitudinal cords 86, as shown in Figure 26. The overall thickness of the conveyor belt 82 is approximately 30mm.

The protruding portions of the steel rope loops 84 have an internal diameter of about 4mm, and preferably a pair of the loops 84 are provided at each connection point to keep the diameter of the steel rope to a minimum, and for redundancy. As shown in Figure 27, a mounting plate of carry roller support arm 88 of this embodiment is provided with a pair of semicircular loop retaining grooves 90, on which the pair of steel rope loops 84 are received. A restraining cover plate 92 slides over the retaining grooves 90, and is retained on the support arm 88 by a tongue and groove sliding arrangement, to restrain the steel rope loops 84 in the retaining grooves 90. A locking bolt 94 locks the cover plate 92 onto the support arm 88. The entire mechanical arrangement for connecting the carry roller support arms 88 to the belt 82 allows for a secure connection, and also facilitates rapid changeover for repair or replacement of a roller and/or support arm.

Advantageously the rope conveyor system further comprises first and second sealing skirts 30 provided along the respective edges of the conveyor belt 12. The sealing skirts 30 are typically made from rubber sheeting. The mounting plates 28 of the carry roller support arms 22 may be used to clamp and hold the sealing skirts 30 in place (see Figure 6). In use, when the belt 12 assumes a partially-enclosed curved shape in cross-section, as shown in Figures 1 , 2 and 5, the sealing skirts 30 overlap so as to substantially enclose the material 18 within the conveyor belt 12. The enclosed environment within the belt 12 helps to restrict any material 18 from bouncing out of the conveyor, in the event of a partially-loaded belt, as well as to support steep incline conditions.

The rubber sealing skirts 30 have increased cross-stiffness to achieve a proper sealing effect at the overlap. The sealing skirts 30 also provide guidance for the carry rollers 16 at the return pulley 34, to avoid any uncontrolled movements of the carry roller support arms 22, due to centrifugal forces. In case the sealing skirts 30 does not provide sufficient guidance for the carry rollers 16 when travelling around the pulley 34, a guiding bar (not illustrated) may be provided which will support the rollers when moving around the pulley. The conveyor belt 12 is driven by a discharge pulley (drum) 32 at the top end of the rope conveyor system 10 and a return pulley (drum) 34 at the bottom end of the conveyor 10 (see Figures 7 and 8). The conveyor pulleys 32, 34 are very similar to standard conveyor pulleys used for most other conveyor systems. The main difference is the additional area provided on the drum surface to support the carry rollers 16 during their travel around the pulley. The sealing skirts 30 are connected to the support arms 22 which travel at a larger radius compared to the pulley diameter. Due to the different diameter the sealing skirts 30 will press the carry rollers and their support arms to the surface of the drum 32, 34, which avoids any unwanted movements due to the centrifugal forces. Belt cleaners are located at the discharge pulley to provide appropriate belt cleaning.

At the loading end of the conveyor, adjacent to the return pulley (drum) 34, the belt 12 passes through a transition zone 36, where it changes configuration from a partially-flattened shape in a loading zone, below loading facility 38, into the partially-enclosed curved shape it assumes when loaded with material 18. A plurality of guiding bars 40 are provided to guide the carry rollers 16 through the transition zone 36 and the loading zone (see Figures 9 to 15). On the underside of the transition zone (see Figure 9) the guiding bars 40a are mainly used to lift the carry rollers off the suspension ropes 14c and 14d, and then on the topside guiding bars 40b guide them along the loading and transition zones onto the suspension ropes 14a and 14b.

For this purpose, on the topside, the guiding bars 40b begin at a spacing corresponding to slightly less than the full width of the conveyor belt 12, guiding the carry rollers 16 so they keep the belt 12 open in a more flattened condition as it passes through the loading zone, and then the guiding bars 40b gradually move inwards until they reach the spacing of the suspension ropes 14, so that the carry rollers 16 close the belt 12 allowing it to assume it's water-drop shape (see Figures 11 to 13). As the spacing between the guiding bars reduces, the sealing skirts 30 will overlap and form a contained volume for the material 18 within the conveyor belt 12. The guiding bars 40 guide the carry rollers between the return pulley 34 and the end of the transition zone 36 on both the topside and underside. Outside the transition zone the carry rollers 16 will be guided by the suspension ropes 14. Figure 12 shows the carry rollers 16 on the guiding bars 40b, just prior to engaging with the suspension ropes 14a and 14b. The suspension ropes 14 and guiding bars 40 ensure the accurate tracking of the conveyor belt at all times.

A top restrain frame 44 is provided on the topside to redirect the suspension ropes 14a and 14b around the transition zone 36 and provide for the required space in the transition zone for the guiding bars 40b (see Figure 14, shown in sketch typical only). The suspension ropes 14a and 14b are connected to the anchor points 50a and 50b, (see Figure 14, shown in sketch typical only). Likewise, a bottom restrain frame 46 is provided on the underside to redirect the suspension ropes 14c and 14d around the transition zone 36 and provide for the required space in the transition zone for the guiding bars 40a (see Figure 15, shown in sketch typical only). The suspension ropes 14c and 14d are connected to the anchor points 50c and 50d, (see Figure 15, shown in sketch typical only).

Figures 16 to 19 illustrate a second embodiment of a rope conveyor system 60 in accordance with the invention. The rope conveyor system 60 is similar to the first embodiment of the rope conveyor system 10 illustrated in Figures 1 to 15, and therefore the same parts will be identified using the same reference numerals and will not be described again in detail. The rope conveyor system 60 comprises a conveyor belt 12 suspended from a flexible elongate member 14. The conveyor belt 12 has a pair of carry rollers 16a and 16b provided on respective first and second edges of the conveyor belt 12 for rolling engagement with the flexible elongate member 14. In use, when the conveyor belt 12 is loaded with material 18 and is suspended from the flexible elongate member 14, the belt 12 assumes a partially-enclosed curved shape in cross-section, as illustrated in Figures 18 and 19. The primary difference between this embodiment and the previous embodiment is that the rope conveyor system 60 only employs a single flexible elongate member 14a for supporting the belt 12 in its loaded condition. Preferably a pair of carry rollers 16a and 16b respectively engages with the single flexible elongate member 14a. In other respects the rope conveyor system 60 is substantially identical to the rope conveyor system 10. Preferably the pair of carry rollers 16a and 16b is one a plurality of pairs of carry rollers 16 provided at spaced intervals throughout the length of the conveyor belt 12.

Preferably the flexible elongate member 14a is one of a plurality of elongate flexible members 14 provided in the rope conveyor system 60. Second and third flexible elongate members 14c and 14d are spaced below the first flexible elongate member 14a, from which the conveyor belt 12 is suspended on the carry rollers 16 during its return journey. During its return journey the conveyor belt is turned inside out and upside down, and typically assumes an open U-shape in cross-section, as shown in Figures 16 and 17. In this manner a single suspension rope option can be realized for a single flight conveyor system 60. One disadvantage of the single flight conveyor system 60 is that no stabiliser frames would be used and the use of a maintenance trolley would therefore be more complicated. One advantage is an improved sealing system, as there is greater overlap of the sealing skirts 30 when the belt 12 assumes a partially-enclosed curved shape in cross- section, as shown in Figures 18 and 19. The single flight conveyor system 60 uses a similar guiding bar arrangement as the dual rope system 10, however additional guiding rollers are used for the carry side to engage the carry rollers 16 with the rope 14a.

Figures 20 and 21 illustrate a preferred embodiment of a lift-off protection system applied to the rope conveyor system 10 of the first embodiment. Two small lift-off protection ropes 54 are installed directly above the return belt carry rollers 16 to avoid any lift-off of the conveyor belt 12 during its return journey under strong wind conditions. This may be necessary as the belt 12 is relatively lightweight when it is empty of material 18 during its return journey. As with all of the other flexible elongate members 14 of the rope conveyor system 10, the lift-off protection ropes 54 are also mounted on the stabiliser frame 20. Figures 22 to 26 illustrate a third embodiment of a rope conveyor system 70 in accordance with the invention. The rope conveyor system 70 is similar to the first embodiment of the rope conveyor system 10 illustrated in Figures 1 to 15, and therefore the same parts will be identified using the same reference numerals and will not be described again in detail. The rope conveyor system 70 comprises a conveyor belt 12 suspended from a pair of flexible elongate members 14a and 14b. The conveyor belt 12 has a pair of carry rollers 16a and 16b provided on respective first and second edges of the conveyor belt 12 for rolling engagement with the respective flexible elongate members 14a and 14b. In use, when the conveyor belt 12 is suspended from the flexible elongate members 14a and 14b, the belt 12 assumes a partially-enclosed curved shape in cross-section. As with the rope conveyor system 10, the plurality of flexible elongate members 14 is supported in a stabiliser frame 72, which maintains a constant distance between the first and second flexible elongate members 14a and 14b, and also distributes forces transferred to the flexible elongate members 14 from the carry rollers 16. In this embodiment third and fourth flexible elongate members 14c and 14d are also supported on the stabiliser frame 72, spaced below the first flexible elongate members 14a and 14b, from which the conveyor belt 12 is suspended on the carry rollers 16 during its return journey. During its return journey the conveyor belt 12 is turned inside out and upside down, and typically assumes an open U-shape in cross- section, as with the previous embodiments.

However in this embodiment the stabiliser frame 72 extends down around the outside of the belt 12 on its return journey, to support the third and fourth flexible elongate members 14c and 14d, as can be seen most clearly in Figures 23 and 25. This is because in this embodiment the rope conveyor system 70 is designed for material discharge along the length of the conveyor. Material 18 is loaded onto the belt 12 prior to its return journey, and so is carried underneath when the belt assumes an open U-shape in cross-section. One side of the conveyor belt 12 is adapted to be derailed during its return journey. After one side is derailed the belt 12 is lowered into a vertical position and will be only supported by one of the suspension ropes 14c and 14d, as illustrated in Figures 22 and 24. During the process of lowering the belt 12 the material 18 will be discharged.

A guiding bar 80 will be used to lift the carry rollers 16 off the suspension rope 14c and to derail it, in order to commence the discharge of material. The position of the discharge point can be changed by moving the guiding bar 80 along the rope system. The weight of the material 8 will force the conveyor belt 12 down on one side to a lowered position. As with the previous embodiments, preferably first and second sealing skirts 30 are provided along the respective edges of the conveyor belt 12. In this embodiment the sealing skirt 30 is of increased width on the belt side that is derailed, so as to cover the carry rollers 16 from any material 18 during the discharge process. The carry rollers 16 will be used at the return pulley (drum) to guide the belt into a flattened configuration.

The rope conveyor system 70 may be used as a stacker and heap leach spreader or dump spreader. Each end of the conveyor system 70 is supported by a mobile machine which is heavy enough to transfer the horizontal suspension rope forces via friction (or rail system) into the ground. The mobile machines can be either crawler or rail mounted. The conveyor 70 is elevated to a level to clear the stockpile of material underneath. The discharge along the conveyor system 70 will be used to discharge the material at the location as required. An advantage of this conveyor 70 is a cost advantage compared to current systems, as well as increased stockpile capacity especially for dozer reclaimed stockpiles. The system can also be arranged to form a circular stockpile, using a central slew column which supports one side of the conveyor 70 and the other end supported by a mobile machine travelling in a circle. The conveyor system can be easier relocated in the event of short term operations.

The rope conveyor system 10 can also be used as a cross-pit spreader or conveyor bridge 100, as illustrated in Figures 28 to 30. Each end of the conveyor system 10 is supported by a mobile machine which is heavy enough to transfer the horizontal rope forces via friction into the ground. The mobile machines are typically be supported by crawlers. The loading end of the conveyor may be located, for example, at the bottom of the pit, and the other end at the top of the dump, at the location to which the material is required to be lifted. A first crawler 102 is located at a mine face, and a second crawler 104 is mounted at a dump area. The cross-pit spreader 100 can be used with any mining equipment, e.g. a bucket wheel excavator 106, feeder, etc.

The first crawler 102 has a receiving boom 108 pivotally mounted on a receiving boom slew deck 110, as shown in Figure 29. The slew deck 1 10 is supported on a rope conveyor slew frame 112 which is mounted on the crawler 102. The ore is conveyed from the excavator 106 to a receiving chute 1 14 at the end of the receiving boom 108, and from there it is conveyed up the boom 108 to the slew deck 1 10, where it feeds through another chute into the rope conveyor system 10. Advantageously the crawler 102 is provided with a hydraulically operated claw system 116, mounted on the underside of a crawler chassis to increase the ground friction factor. The claw system 1 16 facilitates additional transfer, via friction into the ground, of the horizontal tension forces from the rope conveyor system 10.

The second crawler 104 comprises a triangular truss frame, on which a rope winch system 1 18 is mounted for controlling rope tension and to increase flexibility of the rope conveyor system 10, as shown in Figure 30. In the event of rope overload or unwanted movement of a crawler unit, the winch system can release rope and the rope curve will be changed, which in turn leads to reduced rope tension. Ore conveyed via the rope conveyor system 10 discharges at a discharge point 1 19, which can be designed with a curved end to reduce inclination at the discharge point. As with the first crawler 102, the second crawler 104 may also be fitted with a claw system 1 16, mounted on the underside of a crawler chassis to increase the ground friction factor.

The advantage of the cross-pit spreader or conveyor bridge 100 is that the machine weight and costs are 50% to 60% lower compared to a conventional cross-pit spreader or a mobile bridge arrangement. The rope conveyor system is able to span larger distances compared to conventional systems, e.g. horizontal distance between crawlers 320m. The discharge unit can also be placed further away from the dump edge. The rope conveyor system allows steeper belt inclinations, which enables increased dump heights. The system is also easily relocatable compared to current systems. The rope conveyor system may be especially suitable for strip mining applications.

The rope conveyor system can also be used as a wharf conveyor system 120, as illustrated in Figures 31 to 34. Jetties required to connect the main land with a ship loading wharf structure are expensive. The rope conveyor system appropriately modified as a wharf conveyor system 120 offers a very cost effective alternative for loading ships offshore. The wharf conveyor system 120 is similar to the first embodiment of the rope conveyor system 10, and so that the similar parts will be identified with the like reference numerals and will not be described in detail. The system 120 comprises a conveyor belt 12 suspended from a pair of flexible elongate members 14a and 14b. The conveyor belt 12 has a pair of carry rollers 16a and 16b provided on respective first and second edges of the conveyor belt 12 for rolling engagement with the respective flexible elongate members 14a and 14b. In use, when the conveyor belt 12 is loaded with material 18 and is suspended from the flexible elongate members 14, the belt 12 assumes a partially- enclosed curved or "water drop" shape in cross-section, as illustrated in Figures 32 and 33.

As with the previous embodiments, the plurality of flexible elongate members 14 is supported in a stabiliser frame 122, which maintains a constant distance between the first and second flexible elongate members 14a and 14b, and also distributes forces transferred to the flexible elongate members 14 from the carry rollers 16. Advantageously third and fourth flexible elongate members 14c and 14d are also supported on the stabiliser frame 122, spaced below the first and second flexible elongate members 14a and 14b, from which the conveyor belt 12 is suspended on the carry rollers 16 during its return journey. During its return journey the conveyor belt is turned inside out and upside down, and typically assumes an open U-shape in cross- section, as shown in Figures 32 and 34. The distance between the third and fourth flexible elongate members 14c and 14d for return belt support rollers is increased to provide a spillage collection feature. In the event of any spillage, the material will be collected by the return belt.

The wharf rope conveyor system 120 is supported by a plurality of support columns 124, located in the seabed at suitable spaced intervals, e.g. 150m to 200m (to be optimised), as shown in Figure 31 . A roller guiding system 126 is provided in a modified stabiliser frame provided at the top of each support column 124. Shiploader operation personnel and maintenance access to wharf would be provided by a gondola 128 travelling along support ropes (which can be arranged on one side only to allow dual access). In case of port expansion, additional rope conveyor systems can be added in a stacked layout by using the original support columns 124. The environmental impact of the wharf rope conveyor system 20 compared to a traditional jetty would be significantly reduced. Ship, ocean and fish movement would be less impacted by rope conveyor layout. Beach areas, which sometimes present a heritage and environmental issue could be avoided by the use of a rope conveyor system. Based on the reduced costs of a rope conveyor system the distance of loading wharfs can be moved further off shore, without increasing the costs compared to a traditional jetty arrangement, which provides a significant dredging cost reduction.

In each of the forgoing embodiments the elongate members 14 have been flexible elongate members, for example, steel suspension ropes or cables. However there may be some applications where the flexible elongate members 14 may be replaced with substantially rigid elongate members, such as steel rods or pipes.

Figures 35 and 36 illustrate another embodiment of the rope conveyor system in the form of an underground conveyor system 130. The underground rope conveyor system 130 can either supported by a rope or a pipe system. In the illustrated embodiment the conveyor system 130 comprises a conveyor belt 132 suspended from a pair of elongate members 134a and 134b. The conveyor belt 132 has a pair of carry rollers 16a and 16b provided on respective first and second edges of the conveyor belt 132 for rolling engagement with the respective elongate members 134a and 134b. In use, when the conveyor belt 132 is loaded with material 18 and is suspended from the elongate members 134, the belt 132 assumes a partially-enclosed curved or 'water-drop' shape in cross-section, as shown in Figure 36.

In this embodiment the elongate members are pipes 134, supported on roof mounted support frames 136. The support frames 136 are located at spaced intervals along the underground tunnel roof, and support the belt 132 in both its carrying and return belt capacity. The carrying and return belt can be arranged side by side to reduce the overall height of the conveyor system 130. Optionally the belt 32 may be reinforced with a plurality of central cords 138, as can be seen in Figure 36. No regular maintenance access is required along the rope conveyor system 130.

Now that preferred embodiments of the rope conveyor system have been described in detail, it will be apparent that the described embodiments provide a number of advantages over the prior art, including the following:

(i) Steep incline conveying with high capacity e.g. out of the pit conveyor, power plants, strip mining.

(ii) Enclosed conveying to either protect the environment or the material e.g. ash handling, coal handling in populated areas.

(iii) Traversing challenging terrain, e.g. river crossing, mountains, valleys.

(iv) Overland conveyor with limited access (no ground access required), environmental friendly, no barriers for animals, etc. low noise, limited ground disturbance.

(v) Reducing energy consumption due to low rolling resistance.

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, although in each of the described embodiments, first and second elongate flexible members are provided for supporting the conveyor belt on the carry rollers during its return journey, it will be understood that only a single elongate flexible member may be provided for the return journey. The single elongate flexible member may be used to support the carry rollers on both sides of the conveyor belt, or only the carry rollers on one side of the belt, during its return journey. Therefore, it will be appreciated that the scope of the invention is not limited to the specific embodiments described.