ZA200505494B

ZA200505494B - Mine supports

Info

Publication number: ZA200505494B
Application number: ZA200505494A
Authority: ZA
Inventors: Ian G Gallie
Original assignee: Nampak Products Ltd
Priority date: 2004-07-26
Filing date: 2005-07-07
Publication date: 2006-04-26

Description

Co 20050200

THIS INVENTION relates, broadly, to mine supports. More particularly, the invention relates to a bag for forming part of a mine support of the type which supports a hanging wall above a foot wall underground in a mine; and to a mine support comprising the bag filled with a set cementitious grouting material. The invention extends also to a method of supporting a hanging wall above a foot wall underground in a mine, using the bag.

According to the invention there is provided a bag for forming part of a mine support, the bag having opposed upper and lower end wall panels respectively for bearing against a hanging wall and a foot wall underground in a mine, and one or more side wall panels interconnecting the end wall panels, the bag including a central sleeve located in the interior of the bag and connected to the lower end wall panel, the sleeve extending upwardly from a central opening in the lower end wall

2005 05454 panel, to a central part of the upper end wall panel, to which it is connected, the : central sleeve having a lower end edge extending along and joined to the periphery of said central opening with which it communicates, the bag being provided with a } charging inlet for receiving unset grouting material in flowable form, the charging ) inlet being through a side wall panel and comprising a one-way non-return inlet valve.

While the end panels and the horizontal cross-section of the bag will typically have the same outline which may in principle be of any desired shape, such as circular, oval, elliptical or triangular, the shape is preferably rectangular and more preferably square. Accordingly the end wall panels may be of the same size and outline, being square, the bag having four rectangular side wall panels all of the same size and outline, each side wall panel connecting an edge of one of the end wall panels with an edge of the other end wall panel so that the bag, when inflated and filled with flowable grouting material, assumes the shape of a rectangular block.

The bag, when inflated or filled with flowable grouting material, will thus be in the shape of a rectangular block. Preferably, the side wall panels have an outline which is elongated, the side wall panels having long side edges along which they are joined together in series and short end edges, the inlet of the bag being located nearer to one of the short edges of one of the side wall panels than to the other, at a central position, midway between the long side edges of the panel, the short edge of said side wall panel nearer to which the inlet of the bag is located in use being the upper edge of the side wall panel. In this case the inlet of the bag may be located near the upper edge of one of the side wall panels, at a central position, midway : between the side edges of the panel. ) The sleeve may be of constant circular cross-sectional outline, being right- . cylindrical in shape, the central opening in the lower end wall panel being circular in outline and of the same size as the circular cross-sectional outline of the sleeve.

The upper end wall panel may have a central opening of the same shape and size as the central opening of the lower end wall panel, the sleeve communicating with the central opening of the upper end wall panel, the sleeve opening out of each of the end wall panels and having its end edges extending along and joined respectively to the peripheries of the openings in the end wall panels.

The upper end wall panel may be reinforced by at least one length of flexible reinforcing material, which length spans the upper end of the central sleeve and which extends diametrically across the upper end of said central sleeve and across said upper end wall panel, from one side of the upper end wall panel to the other. In a particular construction, when the end wall panels are rectangular, in particular square, in outline, there may be two lengths of flexible reinforcing material in the form of webbing extending diagonally across the upper end wall panel, each length extending from a corner of the upper end wall panel to the opposite corner thereof. The lengths of webbing may be in the form of straps connected along their lengths to the upper end wall panel and to each other where they cross each other and span any opening in the upper end wall panel, being connected conveniently along their side edges and conveniently by means of stitching.

2005 05 9y

: When the end wall panels are rectangular or square, the corners formed between the adjacent pairs of side wall panels will have a rectangular shape, and to

) promote maintenance of this rectangular shape each corner may be provided with ; an elongated web in the form of a rectangular panel extending from one end wall to the other, the long side edges of each web being connected, for example by stitching, to the side wall panels forming the corner which it reinforces, the web spanning said corner and separating a space in said corner from the remainder of the interior of the bag, the space extending from one end wall panel to the other and being in the shape of a rectangular isosceles triangle having equal sides provided by the associated side wall panels and a base, opposite the rectangular corner between the side wall panels, provided by the web.

Accordingly, in other words, the end wall panels may be rectangular, each corner between an adjacent a pair of side wall panels being provided with an elongated reinforcing web in the form of a rectangular panel extending from one end wall to the other, the web having long side edges respectively connected to the side wall panels forming said corner, the web spanning said corner and separating a space in said corner from the remainder of the interior of the bag, the space extending from one end wall panel to the other.

In this case said space may have a cross-section in the shape of a rectangular isosceles triangle having equal sides provided by the associated side wall panels and a base, opposite the rectangular corner between the side wall panels, provided by the web.

The web may have a plurality of windows in the form of openings,

spaced in series along its length, for allowing, during inflation of the bag by means of flowable grouting material, flow of grouting material from the remainder of the interior : of the bag (which it enters via the bag inlet) into each said space. i The inlet may be provided by means of an inlet socket of usually more or . less rigid plastics material, the socket having an inner end provided with a one-way non-return inlet flap valve which closes automatically in response to a pressure above atmospheric pressure and exerted thereon by flowable grouting material in the interior of the bag and in contact with the flap.

The material of the bag may be porous, for example by being woven, being at least partially impervious to the solids in flowable cementitious grouting materials, while being pervious to the liquid such as water therein, so that the bag is a so-called weeping bag. Instead, the bag may be impervious to both said solids and water, so that it is not a weeping bag. In the latter case the bag may comprise a pervious outer layer and a water-impervious inner layer or bladder which lines the outer layer and communicates with the inlet. The porous bag or outer layer may be of woven polymeric plastics material, such as woven polypropylene strips, while the webbing may be of woven nylon. Connections between various parts of the bag will, as indicated above, typically be by stitching.

Further according to the invention there is provided a mine support comprising a bag as defined and described above, the bag being substantially filled with set cementitious grouting material and having its lower end wall panel resting on a foot wall underground in a mine, with its upper end wall panel supporting a hanging wall spaced above the foot wall, the set grouting material being under : compression. ) As will emerge hereunder, the central passage of the sleeve may contain, . in its interior, a prop, typically of timber, having a lower end resting on the foot wall and an upper end holding the centre of the upper end wall panel at an elevated position, at or adjacent the hanging wall. When the bag has one or more straps of flexible reinforcing webbing material spanning a central opening in the upper end wall panel, the upper end of the prop preferably bears upwardly on the or each length of webbing, where they cross each other, thereby to hold up the centre of the upper end wall panel.

The invention extends also to a method of supporting a hanging wall underground in a mine at a position spaced above a foot wall in the mine, the method comprising inserting a prop via the opening in the lower end wall panel into the sleeve of a bag in accordance with the present invention as defined and described above, resting a lower end of the prop on the foot wall with the prop extending upwardly from the foot wall to the hanging wall with the upper end wall supported, typically at its centre, on the upper end of the prop at an elevation at or adjacent that of the hanging wall, and inflating the bag with flowable grouting material under pressure via the inlet, the inflating being discontinued when the bag is sufficiently filled, the grouting material then being allowed to set with the lower end wall panel spread out on the foot wall and the upper end wall panel spread out and located at or adjacent the hanging wall.

The invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings, in which: i Figure 1 shows a schematic three-dimensional view of a bag in accordance with ; the present invention, in an inflated condition, for forming a mine support;

Figure 2 shows a schematic sectional plan view of the bag of Figure 1, in the direction of line II - II in Figure 1; and

Figure 3 shows a schematic sectional elevation of the bag of Figure 1, in the direction of line III - III in Figure 2.

In the drawing, the bag is designated by reference numeral 10. The bag is block-shaped and rectangular, being formed from six panels of woven polypropylene strips, namely a lower end wall panel 12, an opposed upper end wall panel 14, and four side wall panels, respectively 16, 18, 20 and 22.

The lower end panel 12 has a circular central opening 24 therethrough, the upper end panel 14 having a registering circular central opening 26 therethrough of the same size. The openings 24 and 26 are connected by a right-cylindrical sleeve 28 whose circular cross-section is of the same size as the openings 24, 26, the sleeve 28 being open-ended and opening out at its opposite ends through the respective end panels 12, 14. The end edges of the sleeve 28 extend respectively along the peripheries of the openings 24, 26, to which peripheries said end edges are connected.

The upper end panel 14 is reinforced by a pair of straps 30, 32 of woven : nylon webbing. The straps 30, 32 extend along the diagonals of the panel 14, from one corner of the panel 14 to the diagonally opposite corner. The straps 30, 32 are ’ connected along their edges to the panel 14 and span its opening 26, being . connected to each other where they cross each other.

The panel 16 has an inlet socket 34 connected thereto, spaced from and adjacent the upper edge of the panel 16, and located centrally between the side edges of the panel 16. The socket 34, at its inner end, is provided with a one-way non-return flap valve (not shown).

The panels 12, 14 are square in outline and of the same size; and the panels 16 — 20 are all of the same elongated rectangular outline, having long side edges and short upper and lower edges of the same length as the edges of the panels 12, 14 respectively. The panels 16 — 20 are connected in series to one another at corners 36 of the bag 10. End edges of the panels 16 — 20 are in turn connected to associated edges of the panels 12, 14.

Each corner 36 is provided with an elongated reinforcing web 38 in the form of a rectangular panel. As is the case with the sleeve 28, the webs 38 are of the same woven polypropylene strip material as the end and side wall panels 12 — 22. Each web 38 extends from the panel 12, to which it is not connected, to the panel 14, to which it is also not connected, the web 38 having long side edges connected at 40 respectively to the adjacent pair of side wall panels (16 — 22 as the case may be). The webs 38 are shown in Figure 3 connected at 40 to the respective : panels 20, 22. Each web 38 has a series of centrally positioned circular windows 42 spaced along its length, as is apparent from Figure 3. . As mentioned above, the panels 12 — 22, the sleeve 28 and the webs 38 are of woven polypropylene strip material, which is porous, the straps 30, 32 being of woven nylon webbing. Unless otherwise specified, all the connections between the various panels, the sleeve 28 and the straps 30, 32 are by way of stitching where necessary, the bag being a so-called weeping bag, as described hereunder.

Naturally, two or more of the panels, for example the panels 16 — 22, may be integral extensions in series of one another, if convenient. With regard to the dimensions of the bag illustrated in the drawings, it is expected that the panels 12, 14 will typically be 500 - 1200 mm on a side, being about 650mm in the illustrated example. The panels 16 — 22 will typically have a height of 600 - 1800 mm being about 1200mm in the illustrated example. The sleeve 28 will typically have a diameter of 180 300mm, being about 250mm in the illustrated example. The webs 38 in turn will have a width of 200 — 500 mm, being about 300mm in the illustrated example. The straps 30, 32 will typically have a width of 40 - 90mm, the width being about 60mm in the illustrated example. Finally, the windows 42 in the webs 38 will typically have a diameter of 100 - 200mm, the spacing between them 50 - 300mm, the illustrated example showing window diameters of about 150mm and spacings of about 100mm between windows.

In use the bag 10 is used to support a hanging wall in a stope : underground in a mine above a foot wall. To do this, a timber prop or so-called stick prop (not shown) is inserted into the sleeve 28 via the opening 24 in the panel 12 : with a working peripheral clearance between the prop and the sleeve in the radial ] direction typically of 10 - 200mm, in the illustrated example about 15mm. The prop will be selected or cut so that, when it is vertical in a mine, having a lower end resting on a foot wall, its upper end is jammed against or closely spaced from the associated hanging wall, so that it can be jammed in place by one or more shims or similar packing elements, if desired. The prop bears upwardly on the straps 30, 32, where they cross each other, and jams them to the hanging wall or holds them closely spaced from the hanging wall.

The bag 10 is inflated and filled with a cementitious grouting material such as a cementitious slurry, via the inlet socket 34. Filling continues until the bag 10 is distended, with the panel 12 bearing against the foot wall, over which it is spread out, and the panel 14 bearing against the hanging wall, against which it is spread out. The grouting material is then allowed to set. The porosity of the panels 12 — 22 is selected to permit water from the slurry to weep therethrough, while retaining substantially all the slurry solids in the bag to set into a block-shaped mine support pillar, capable of supporting the hanging wall for a sufficient period above the foot wall, to permit mining in the vicinity of the pillar to be carried out to completion.

Naturally, in use, the spacing between the pillars will be selected with the propensity of the stope spontaneously to close in mind.

With particular reference to the illustrated example, the problem to which the invention provides the solution is that prior devices known to the Applicant require metal rings or other supports to keep them upright while they are being filled, : to support them to resist their falling over and to resist their bulging into a non- ] rectangular shape; and the advantages in this context of the illustrated example are that no more than a timber prop is needed to keep the bag 10 upright, the construction of the bag tending to resist bulging and to keep its shape rectangular.

In this regard it is to be noted that the function of the webs 38 is to maintain the bag in as far as possible a rectangular condition with a square plan view, as is shown particularly in Figure 2 of the drawings. Furthermore, the bag 10 is flexible and foldable and takes up little space while being transported underground, timber props in any event typically being readily available underground for other purposes.

Claims

CLAIMS:

1. A bag for forming part of a mine support, the bag having opposed upper ’ and lower end wall panels respectively for bearing against a hanging wall and a foot . wall underground in a mine, and one or more side wall panels interconnecting the end wall panels, the bag including a central sleeve located in the interior of the bag and connected to the lower end wall panel, the sleeve extending upwardly from a central opening in the lower end wall panel, to a central part of the upper end wall panel, to which it is connected, the central sleeve having a lower end edge extending along and joined to the periphery of said central opening with which it communicates, the bag being provided with a charging inlet for receiving unset grouting material in flowable form, the charging inlet being through a side wall panel and comprising a one-way non-return inlet valve.

2. A bag as claimed in Claim 1, in which the end wall panels are of the same size and outline, being square, the bag having four rectangular side wall panels all of the same size and outline, each side wall panel connecting an edge of one of the end wall panels with an edge of the other end wall panel so that the bag, when inflated and filled with flowable grouting material, assumes the shape of a rectangular block.

3. A bag as claimed in Claim 2, in which the side wall panels have an outline which is elongated, the side wall panels having long side edges along which they are joined together in series and short end edges, the inlet of the bag being located nearer to one of the short edges of one of the side wall panels than to the other, at a : central position, midway between the long side edges of the panel, the short edge of said side wall panel nearer to which the inlet of the bag is located in use being the : upper edge of the side wall panel.

4. A bag as claimed in any one of Claims 1 - 3 inclusive, in which the sleeve is of constant circular cross-sectional outline, being right-cylindrical in shape, the central opening in the lower end wall panel being circular in outline and of the same size as the circular cross-sectional outline of the sleeve.

5. A bag as claimed in any one of Claims 1 — 4 inclusive, in which the upper end wall panel has a central opening of the same shape and size as the central opening of the lower end wall panel, the sleeve communicating with the central opening of the upper end wall panel, the sleeve opening out of each of the end wall panels and having end edges extending along and joined respectively to the peripheries of the openings in the end wall panels.

6. A bag as claimed in any one of Claims 1 - 5 inclusive, in which the upper end wall panel is reinforced by at least one length of flexible reinforcing material, which length spans the upper end of the central sleeve and which extends diametrically across the upper end of said central sleeve and across said upper end wall panel, from one side of the upper end wall panel to the other.

7. A bag as claimed in Claim 6, in which the end wall panels are rectangular ‘ in outline, there being two lengths of flexible reinforcing material in the form of webbing extending diagonally across the upper end wall panel, each length ) extending from a corner of the upper end wall panel to the opposite corner thereof.

8. A bag as claimed in Claim 7, in which the lengths of webbing are in the form of straps connected along their lengths to the upper end wall panel and to each other where they cross each other.

9. A bag as claimed in any one of Claims 1- 8 inclusive, in which the end wall panels are rectangular, each corner between an adjacent pair of side wall panels being provided with an elongated reinforcing web in the form of a rectangular panel extending from one end wall to the other, the web having long side edges respectively connected to the side wall panels forming said corner, the web spanning said corner and separating a space in said corner from the remainder of the interior of the bag, the space extending from one end wall panel to the other.

10. A bag as claimed in Claim 9, in which said space has a cross-section in the shape of a rectangular isosceles triangle having equal sides provided by the associated side wall panels and a base, opposite the rectangular corner between the side wall panels, provided by the web.

11. A bag as claimed in Claim 10, in which the web has a plurality of windows in the form of openings, spaced in series along its length, for allowing, during inflation of the bag by means of flowable grouting material, flow of grouting material : from the remainder of the interior of the bag into each said space. )

12. A bag as claimed in any one of the preceding claims, in which the inlet is i provided by means of an inlet socket of plastics material, the socket having an inner end provided with a one-way non-return inlet flap valve which closes automatically in response to a pressure above atmospheric pressure and exerted thereon by flowable grouting material in the interior of the bag and in contact with the flap.

13. A bag as claimed in any one of the preceding claims, in which the material of the bag is porous, being at least partially impervious to the solids in flowable cementitious grouting materials while being pervious to the liquid therein.

14. A bag as claimed in Claim 1, substantially as described and as illustrated herein with reference to the accompanying drawings.

15. A mine support comprising a bag as claimed in any one of the preceding claims, the bag being substantially filled with set cementitious grouting material and having its lower end wall panel resting on a foot wall underground in a mine, with its upper end wall panel supporting a hanging wall spaced above the foot wall, the set grouting material being under vertical compression.

16. A mine support as claimed in Claim 15, substantially as described and illustrated herein with reference to the accompanying drawings.

17. A method of supporting a hanging wall underground in a mine at a position spaced above a foot wall in the mine, the method comprising inserting a prop via the ) opening in the lower end wall panel into the sleeve of a bag as claimed in any one of 3 Claims 1 — 14 inclusive, resting a lower end of the prop on the foot wall of the mine with the prop extending upwardly from the foot wall to the hanging wall of the mine with the upper end wall of the bag supported on the upper end of the prop at an elevation at or adjacent and below that of the hanging wall, and inflating the bag with flowable grouting material under pressure via the inlet, the inflating being discontinued when the bag is sufficiently filled for the lower end wall panel to be spread out on the foot wall with the upper end wall panel spread out and located at or adjacent the hanging wall, the grouting material then being allowed to set.

18. A method as claimed in Claim 17, substantially as described and as illustrated herein with reference to the accompanying drawings. DATED THIS 7'" day of JULY 2005 AV vR SCHWEIZER ADAMS & ADAMS APPLICANT'S PATENT ATTORNEYS