Provision of support in underground mine workings

Abstract

The invention provides a bag for spacing apart walls in an underground mine working, and including opposed load-bearing walls of flexible sheet material, each defining a substantially centrally located opening and an open-ended radial slot extending between and intersecting the central opening and outer periphery of the load-bearing wall, the openings and slots of the load-bearing walls being in register. There is an intermediate wall of flexible sheet material extending between the load-bearing walls and connected thereto substantially along the entire periphery of each load-bearing wall. A charging connector through the wall is for connection to a source of flowable substance under pressure for charging the bag therewith, to expand the bag by displacing the load-bearing walls away from each other. The invention also provides an installation and method which employ the bag to space the walls apart.

1 . A bag for use in spacing apart a pair of opposed walls in an underground mine working, which bag includes: 
 a pair of opposed load-bearing walls of flexible sheet material, each load-bearing wall defining a substantially centrally located opening and an open-ended radial slot which extends between and intersects both the central opening and the outer periphery of the load-bearing wall, the openings and the slots of the load-bearing walls being in register;    an intermediate wall of flexible sheet material, the intermediate wall extending between the load-bearing walls and being connected to each load-bearing wall substantially along the entire periphery of each load-bearing wall; and    a charging connector through a wall of the bag, for connection to a source of flowable substance under pressure for charging the interior of the bag therewith, to expand the bag by displacing the load-bearing walls away from each other, to provide an expanded bag having a centrally located passage extending therethrough from one load-bearing wall to the other, and an open-ended space intersecting and extending between the centrally located passage and the outer periphery of the bag.    
     
     
         2 . A bag as claimed in  claim 1 , in which the intermediate wall has a width, in a direction from one said load bearing wall to the other, which is constant and has a value of 5-200 cm.  
     
     
         3 . A bag as claimed in  claim 1 , which includes a restraining arrangement for restraining the bag to inhibit widening of the slots by movement of opposite sides of the slots away from each other in response to expansion of the bag.  
     
     
         4 . A bag as claimed in  claim 3 , in which the restraining arrangement comprises at least one pair of ties, the ties of each pair being anchored to the intermediate wall at respective positions selected so that the ties of the pair can be tied together to inhibit said widening of the slots.  
     
     
         5 . A bag as claimed in  claim 4 , in which the bag is provided with a plurality of pairs of ties, the pairs being spaced in series and the series extending, in a direction across the width of the intermediate wall, from one said load-bearing wall to the other.  
     
     
         6 . A bag as claimed in  claim 1 , in which the bag is porous, being at least partially impervious to the solids in a cementitious slurry and being pervious to the water in such slurry.  
     
     
         7 . A bag as claimed in  claim 1 , in which the bag is impervious to both said solids and to water.  
     
     
         8 . A bag as claimed in  claim 7 , which comprises a porous outer layer and a water-impervious bladder which lines the outer layer and is located inside the outer layer, the charging connector being a non-return inlet valve and leading from the exterior of the outer layer into the interior of the bladder.  
     
     
         9 . A bag as claimed in  claim 1 , in which the bag is of a woven polymeric plastics material.  
     
     
         10 . A bag as claimed in  claim 9 , in which the intermediate wall is connected to the load-bearing walls by stitching.  
     
     
         11 . An installation spacing apart a pair of opposed walls in an underground mine working, which installation includes: 
 an elongated strut extending between said opposed walls of the underground mine working, with ends of the strut respectively abutting said opposed walls of the underground mine working and with the strut under compression; and    a plurality of bags, each bag including a pair of opposed load-bearing walls of flexible sheet material, each load-bearing wall defining a substantially centrally located opening and an open-ended radial slot which extends between and intersects both the central opening and the outer periphery of the load-bearing wall, the openings and the slots of the load-bearing walls being in register, an intermediate wall of flexible sheet material, the intermediate wall extending between the load-bearing walls and being connected to each load-bearing wall substantially along the entire periphery of each load-bearing wall, and a charging connector through a wall of the bag, for connection to a source of flowable substance under pressure for charging the interior of the bag therewith, to expand the bag by displacing the load-bearing walls away from each other, to provide an expanded bag having a centrally located passage extending therethrough from one load-bearing wall to the other, and an open-ended space intersecting and extending between the centrally located passage and the outer periphery of the bag, the bags received on the strut, the bags being arranged face-to-face in series with one another with the load-bearing walls of adjacent bags in abutment, the series extending along the strut from one said wall of the underground mine working to the opposed wall of the underground mine working, each bag containing a solid substance under compression whereby the bag is at least partly expanded, and the strut passing through the centrally located openings of the load-bearing walls of each bag.    
     
     
         12 . An installation as claimed in  claim 11 , in which the opposed walls of the underground mine working are a foot wall and a hanging wall of a stope forming part of the underground mine working, the strut and the series of bags extending upwardly from the foot wall to the hanging wall and supporting the hanging wall above the foot wall.  
     
     
         13 . An installation as claimed in  claim 11 , in which the opposed walls of the underground mine working are a pair of opposed side walls of a stope, the strut and series of bags extending more or less horizontally between said side walls.  
     
     
         14 . An installation as claimed in  claim 11 , in which each bag comprises an annulus which is interrupted by a radially extending space, opposed parts of the intermediate wall of the bag, at the radially outer end of the space, being fastened together to inhibit widening of the space in response to expansion of the bag.  
     
     
         15 . An installation as claimed in  claim 11 , in which the bags are received on the strut in an arrangement such that the spaces of successive bags are angularly offset relative to each other so that said spaces are out of register with each other when viewed lengthwise relative to the series.  
     
     
         16 . A method of spacing apart a pair of opposed walls in an underground mine working in which a strut is held captive and under compression by abutment of ends of the strut respectively against a pair of opposed walls forming part of the underground mine working, the strut extending between said walls, the method including the steps of: 
 positioning a plurality of bags in series on the strut, each bag including a pair of opposed load-bearing walls of flexible sheet material, each load-bearing wall defining a substantially centrally located opening and an open-ended radial slot which extends between and intersects both the central opening and the outer periphery of the load-bearing wall, the openings and the slots of the load-bearing walls being in register, an intermediate wall of flexible sheet material, the intermediate wall extending between the load-bearing walls and being connected to each load-bearing wall substantially along the entire periphery of each load-bearing wall, and a charging connector through a wall of the bag, for connection to a source of flowable substance under pressure for charging the interior of the bag therewith, to expand the bag by displacing the load-bearing walls away from each other, to provide an expanded bag having a centrally located passage extending therethrough from one load-bearing wall to the other, and an open-ended space intersecting and extending between the centrally located passage and the outer periphery of the bag, the positioning of the bags on the strut being so that the strut is received in the centrally located openings of the load-bearing walls of each bag; and    at least partially expanding each bag by means of a flowable substance under pressure to place each bag under compression and to cause it to assume an expanded shape.    
     
     
         17 . A method as claimed in  claim 16 , which includes the step, prior to the expanding, of fastening together opposed parts of the intermediate wall at or adjacent the outer periphery of the bag, to restrain and inhibit moving apart of said opposed parts in response to the expanding of the bag.  
     
     
         18 . A method as claimed in  claim 16 , which includes the step of positioning the strut between a foot wall and a hanging wall in a stope forming part of the underground mine working, so that the strut extends upwardly from the foot wall to the hanging wall of the stope, and so that the bags form a stacked series which extends upwardly from the foot wall to the hanging wall.  
     
     
         19 . A method as claimed in  claim 16 , in which the step of positioning the bags is such that they are arranged with the spaces of successive bags angularly offset relative to each other so that said spaces are out of register with each other when viewed lengthwise relative to the series.