GB2068873A - Shuttle conveyor with screens for the working zone - Google Patents

Abstract

A shuttle conveyor 1 for transporting material in a mineral mine working is provided with a screen capable of screening off the working zone. The screen is supported for pivoting to a collapsed position permitting access to the working zone. The screen is composed of a series of trapezium-shaped screen plates 15, 16 arranged end-to-end. Each screen plate 15, 16 is pivotally connected to the conveyor 1 along the longer of its parallel sides. Each of the gaps 19, 21 formed between the adjacent pairs of screen plates 15, 16 is at least substantially covered by a respective cover plate 22, 23. <IMAGE>

Description

SPECIFICATION Shuttle conveyor The invention relates to a conveyor for transporting mineral ores, and in particular to a shuttle conveyor for transporting ores won by drilling and blasting operations.

A shuttle conveyor has a scraper-chain assembly which is reciprocated along a series of conveyor sections or pans. The individual scrapers of a shuttle conveyor are made to pivot between a working position (in which material is transported), when the assembly is moving in a first, conveying direction, and a second position (in which little or no material is transported), when the assembly is moving in a second, return direction opposite to the conveying direction.

When valuable ores, such as gold, are being mined, it is important to prevent loss of material during both winning and conveying.

It is known, where valuable ore material is to be detached from a mineral face by drilling and blasting operations (as is used for gold mining), to use some form of screen or shield to retain the mined material in the working zone. Such a screen should extend as far as the roof of the mine working, and is usually attached to the conveyor.

In a known conveyor/screen arrangement, two rectangular screen plates are attached to each section or pan of the conveyor, the remote ends of the two screen plates lying above the joints connecting that pan with the two adjacent pans. The adjacent ends of the adjacent screen plates of each pair of adjacent pans are covered by cover plates, and each cover plate is bolted to both its associated screen plates. No cover plates are provided, however, for the adjacent ends of the screen plates of the same pan. This is because, in the contrast to the end regions of the pans where articulation with the adjacent pans has to be accommodated, there is no need to worry about the screen plates of the same pan moving relative to one another and so opening up a gap.

The screen plates of this known arrangement are pivotally mounted on the conveyor about an axis extending longitudinally of the conveyor. Thus, each pair of screen plates which are held together by a bolted-on cover plate can be lowered together to gain access to the working zone between blasting operations.

This known form of arrangement suffers from a number of disadvantages. In particular, articulation between adjacent pans can force the upper edges of the adjacent ends of the adjacent screen plates against one another, and this may damage the screen plates or the articulated joints between the pans. Moreover, the articulation between adjacent pans is constrained by the fact that the adjacent screen plates are held together by the bolted-on cover plates. This constraint occurs even when the cover plates are bolted to the screen plates in such a manner as to permit a certain degree of play therebetween.

Another disadvantage of this known form of arrangement arises from the requirement that the two screen plates of a given pan must leave only a very narrow gap between their facing ends. Otherwise, small pieces of mined material could become jammed in the gaps, thus hindering the conveying process. Unfortunately, it is very difficult to mount the screen plates sufficiently accurately to ensure these gaps are sufficiently small. Particularly where valuable ore material, such as gold, is being mined, excessively wide gaps also lead to an undesirable loss of material.

A further disadvantage is that the screen plates have to be raised and lowered in pairs.

As these screen plates are relatively heavy, even where seams are only moderately thick, this results in an excessive amount of operator time being taken up with the positioning and lowering of the screen.

The aim of the invention is to provide a conveyor for use in transporting ore won by drilling and blasting operations, and which does not suffer from these disadvantages.

The present invention provides a conveyor for transporting material in a mineral mine working, the conveyor being provided with a screen capable of screening off the working zone and supported for pivoting to a collapsed position permitting access to the working zone, wherein the screen is composed of a series of trapezoidal screen plates arranged end-to-end, each screen plate being pivotally connected to the conveyor along the longer of its parallel sides, and wherein each of the gaps formed between the adjacent pairs of screen plates is at least substantially covered by a respective cover plate.

Where the conveyor is constituted by a plurality of pans joined together end-to-end in such a manner as to permit limited articulation therebetween, each pan may have two screen plates pivotally connected thereto.

With this arrangement, all the gaps between adjacent pairs of screen plates are substantially completely covered. Moreover, because of the trapezoidal form of the screen plates, the gaps between adjacent pairs of screen plates diverge towards the roof of the mine working when the screen is in operation.

Consequently, there is no danger of the upper edges of adjacent ends of adjacent screen plates being forced against one another.

in one preferred embodiment, all the cover plates are identical, each cover plates overlapping both its associated screen plates and being attached to one only of said screen plates. In this case, the arrangement not only has the advantage of complete covering of all gaps between the screen plates, but it also has the advantage that all the cover plates are identical, so that there is a manufacturing cost saving.

In another preferred embodiment, there are first and second cover plates, each first cover plate- being associated with adjacent screen plates of adjacent pans and each second cover plate being associated with the screen plates of the same pan, each first cover plate overlapping both its associated screen plates and being attached to one only of said associated screen plates, and each second cover plate overlapping, and being attached to one of its associated screen plates, each second cover plate being spaced slightly from the other of its associated screen plates.

In both preferred embodiments, because the cover plates are attached only to one of their associated screen plates, each screen plate can be raised and lowered individually, so that the entire screen can be raised and lowered relatively quickly and easily.

Advantageously, each cover plate is bolted to said one of its associated screen plates.

Preferably, in said another preferred embodiment, each second cover plate is bolted to said one of its associated screen plates by means of bolts passing through respective elongate slots in that cover plate or in that screen plate, said slots extending parallel to the conveyor. Thus, each second cover plate is infinitely adjustable within a given range determined by the lengths of the slots, and is fixable in any given adjusted position. Consequently, no particular accuracy is required in mounting the screen plates.

A conveyor constructed in accordance with the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a schematic side elevation, seen from the goaf side, of part of the conveyor; Figure 2 is a plan view of the protective screen of the conveyor of Fig. 1; Figure 3 is a cross-section taken on the line Ill-Ill of Fig. land Figure 4 is a cross-section taken on the line IV-IV of Fig. 1.

Referring to the drawings, Fig. 1 shows a shuttle conveyor 1 which is intended primarily for transporting raw material ores won by drilling and blasting operations in an underground working. The conveyor 1 is constituted by a plurality of sections (or pans) 11 arranged end-to-end, and interconnected in a traction-proof manner. The pans 11 are connected by joints 1 3 which, as indicated schematically by the reference numbers 12, permit limited articulation in all three dimensions.

Each of the conveyor pans 11 has a base plate 2 which is inclined at a small angle to the floor F of the working. The base plates 2 of the pans 11 thus define a conveying zone along which a scraper assembly is reciprocable as indicated by the double-arrow 9 (see Fig. 1). The scraper assembly is constituted by a plurality of scrapers 3 which are supported on, and reciprocably drivable along, the base plates 2 by means of a drive chain 4.

The conveyor 1 is provided with a protective screen 5 which extends upwardly towards the roof (not shown) of the working. The upper edge of the screen 5 is provided with a resilient beading 6 (shown in dash-dot lines in Fig. 3 only) which engages the roof to separate the winning area 7 of the working from its access area 8. The actual face from which ore is to be won is not shown in the drawings.

The protective screen 5 is constituted by a plurality of trapezoidal screen plates 1 5 and 1 6. The plates 1 5 and 1 6 are congruent, and each has the longer of its parallel sides facing the floor F of the working and the shorter of its parallel sides facing the roof. The two nonparallel sides of each screen plate 15, 1 6 are of the same length. Each pan 11 has a pair of screen plates 1 5 and 1 6 connected thereto, the remote ends 1 7 and 1 8 respectively of which are aligned with the joints 1 3 connecting that pan to the two adjacent pans.Because of their trapezoidal form, gaps are formed between each pair of adjacent plates 1 5 and 16, these gaps diverging towards the roof of the working. The gaps above the joints 1 3 are indicated by the reference numbers 19, and those above the middles of the pans 11 are indicated by the reference numbers 21. Each gap 1 9 is covered by a cover plate 22, and each gap 21 is substantially covered by a cover plate 23. Each cover plate 22 is attached only to the adjacent screen plate 15, and each cover plate 23 is attached only to the adjacent screen plate 16. Each cover plate 22 overlaps both the adjacent ends of the corresponding pair of screen plates 1 5 and 16.On the other hand, each cover plate 23 overlaps only the screen plate 1 6 to which it is attached, there being a clearance S (see Figs. 1 and 4) between its end face 25 and the end face 26 of the adjacent screen plate 1 5. In order to secure the cover plates 23 to their respective screen plates 16, the cover plates 23 are provided with elongate slots 27 through which bolts (shown schematically as 28) pass. The elongate slots 27 extend longitudinally with respect to the conveyor 1 so that the size of the clearance S can be adjusted accurately.

The downwardly-facing edge of each screen plate 1 5 and 1 6 is provided with a pair of spaced, downwardly-projecting extensions 29.

Each pair of extensions 29 co-operates with a pivot pin 31 and an extension projecting upwardly from the corresponding conveyor pan 11 to form a pivotal connection between that conveyor pan and the respective screen plate 1 5 or 1 6. These pivotal connections are such as to permit the screen plates 1 5 and 1 6 to be pivotally lowered either towards the face side or the goaf side of the working. Consequently, a very versatile arrangement results, in which each of the screen plates 1 5 and 1 6 can be lowered to either side as working conditions may require.

Each of the screen plates 1 5 and 1 6 is provided with a hydraulic support ram 32 (see Fig. 3) which supports that plate in its upright position and acts as a shock-absorber. The rams 32 are mounted on the goaf side of the screen 5 and are articulated to their screen plates 1 5 or 1 6 and to the associated conveyor pans 11.

In an alternative embodiment (not shown), all the cover plates are identical and of the same form as the cover plates 22. In this case, therefore, each of the gaps 19 and 21 is completely covered by a cover plate 22 which overlaps the adjacent edge portions of both the associated screen plates 1 5 and 1 6.

Claims (10)

1. A conveyor for transporting material in a mineral mine working, the conveyor being provided with a screen capable of screening off the working zone and supported for pivoting to a collapsed position permitting access to the working zone, wherein the screen is composed of a series of trapezoidal screen plates arranged end-to-end, each screen plate being pivotally connected to the conveyor along the longer of its parallel sides, and wherein each of the gaps formed between the adjacent pairs of screen plates is at least substantially covered by a respective cover plate.

2. A conveyor as claimed in Claim 1, wherein all the screen plates are identical, the non-parallel sides of each screen plate having the same length.

3. A conveyor as claimed in Claim 1 or Claim 2, wherein the conveyor is constituted by a plurality of pans joined together end-toend in such a manner as to permit limited articulation therebetween.

4. A conveyor as claimed in Claim 3, wherein each pan has two screen plates pivotally connected thereto.

5. A conveyor as claimed in any one of Claims 1 to 4, wherein all the cover plates are identical, each cover plate overlapping both its associated screen plates and being attached to one only of said screen plates.

6. A conveyor as claimed in Claim 4, wherein there are first and second cover plates, each first cover plate being associated with adjacent screen plates of adjacent pans and each second cover plate being associated with the screen plates of the same pan, each first cover plate overlapping both its associated screen plates and being attached to one only of said associated screen plates, and each second cover plate overlapping, and being attached to only one of its associated screen plates, each second cover plate being spaced slightly from the other of its associated screen plates.

7. A conveyor as claimed in Claim 5 or Claim 6, wherein each cover plate is bolted to said one of its associated screen plates.

8. A conveyor as claimed in Claim 7 when appendant to Claim 6, wherein each second cover plate is bolted to said one of its associated screen plates by means of bolts passing through respective elongate slots in that cover plate or in that screen plate, said slots extending parallel to the conveyor.

9. A conveyor as claimed in any one of Claims 1 to 8, wherein the conveyor is a shuttle- conveyor.

10. A shuttle conveyor substantially as hereinbefore described with reference to, and as illustrated by, the accompanying drawings.