WO2013181706A1 - Treillis et procédé de fabrication du treillis - Google Patents

Treillis et procédé de fabrication du treillis Download PDF

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Publication number
WO2013181706A1
WO2013181706A1 PCT/AU2013/000601 AU2013000601W WO2013181706A1 WO 2013181706 A1 WO2013181706 A1 WO 2013181706A1 AU 2013000601 W AU2013000601 W AU 2013000601W WO 2013181706 A1 WO2013181706 A1 WO 2013181706A1
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WO
WIPO (PCT)
Prior art keywords
mesh
attachment regions
reinforcing elements
mine
attachment
Prior art date
Application number
PCT/AU2013/000601
Other languages
English (en)
Inventor
Christian MCLEAN
Original Assignee
Mclean Christian
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from AU2012902371A external-priority patent/AU2012902371A0/en
Application filed by Mclean Christian filed Critical Mclean Christian
Publication of WO2013181706A1 publication Critical patent/WO2013181706A1/fr

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Classifications

    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
    • E21D11/14—Lining predominantly with metal
    • E21D11/15—Plate linings; Laggings, i.e. linings designed for holding back formation material or for transmitting the load to main supporting members
    • E21D11/152—Laggings made of grids or nettings

Definitions

  • the present invention relates to a mesh for supporting the walls of underground mines or any other structures, including naturally occurring structures such as caves, sink holes and alike, and other "man-made” structures such as tunnels, roadways, pathways and alike.
  • the present invention also relates to a method of making the mesh and an underground mine to which the mesh has been installed.
  • a perimeter of a cell of coal is first excavated to allow for the ventilation of fugitive gases from within the cell.
  • the perimeter of the cell essentially comprises a front longwall along which the cutting head of an excavator operates and one or more perpendicular tunnels that form a U-shape.
  • the walls and roof of the tunnels defining the perimeter of the cell are reinforced with a steel mesh which is installed progressively and typically in one metre sections.
  • Steel bolts are used to anchor the mesh in position.
  • the steel mesh comprises drawn steel bars that are welded in a square or rectangular pattern. The combination of bolts and steel mesh can provide an adequate strata reinforcement system that can sustain ground movement and provide passive confinement of fragments that could otherwise fall.
  • the walls of the coal cell including the walls being excavated by mining machinery are properly supported to prevent strata from falling.
  • the steel mesh may damage a cutting head, excavation equipment and subsequent downstream handling systems. To prevent this from ocurring the mesh may be
  • An improvement on the conventional steel mesh is a plastic mesh that is less damaging to the cutting head of the excavating machine and subsequent downstream handling systems.
  • An example of a plastic mesh that is commercially available is a mesh sold under the trade name TENSAR.
  • the TENSAR mesh is made from oriented polypropylene.
  • one of the difficulties experienced with this mesh is that on contact by the cutting head, the mesh can become wrapped around the cutting head which reduces mining efficiency and forces closure of the mining machinery for a period of time. Removing the mesh from the cutting head again exposes an operator to occupational, health and safety hazards at the coal face.
  • the present invention relates to an open mesh for supporting the walls of an underground mine, the open mesh having apertures for visual inspect of mine strata and for venting fugitive gas from the mine strata, wherein the mesh has:
  • attachment regions arranged about the periphery of the mesh that are adapted so that a fastener can operably secure the sheet to the walls of the mine at the attachment regions;
  • reinforcing elements that extend transversely across the mesh and interconnects the attachment regions so as to reduce elongation of the mesh in a direction between the attachment regions when subjected to loads.
  • One of the advantages of the present invention is that by reducing the elongation of the mesh in a direction between points of attachment of the mesh to the strata, deflection of the mesh in a direction normal to the mesh arising from strata movement is reduced and ultimately, the incidence of undesired failure of the mesh is also reduced.
  • the mesh may have a sheet body.
  • the sheet body may self-orient, in a relaxed state, in either i) a flat plane or ii) a curved formation.
  • the mesh may be tensioned so as apply pressure to the wall, and thereby further reduce the risk of frangments falling from the wall.
  • the reinforcing elements may be integrally formed with the mesh, and suitably with the sheet body of the mesh.
  • the attachment regions may also be integrally formed with the mesh, and suitably with the sheet body of the mesh.
  • the sheet body defines the attachment regions, the apertures, and the reinforcing elements. It is also possible for either one or a combination of the attachment regions and the reinforcing elements be joined to the sheet body at one or more points between the attachment regions.
  • the reinforcing elements provide increased dimensional stability to the mesh in a direction between the attachment regions compared to a mesh in which the reinforcing elements are absent.
  • the reinforcing elements may co-inside with the diagonal members, but increase the tensile strength of the mesh in directions between the attachment regions.
  • the reinforcing elements may also be arranged to extend about the perimeter or a peripheral region of the mesh between attachment regions.
  • the reinforcing elements may be interconnected to form reinforced triangular sections. Corners of the triangular sections may be defined by attachment regions.
  • the reinforcing elements may be free of the apertures for venting gases and observing the strata.
  • the apertures may be located to the side or between the reinforcing elements.
  • the attachment regions Depending on the geometric shape of the mesh, the attachment regions
  • interconnected by the reinforcing elements may be non-adjacent attachment regions that are arranged about, or close to, a perimeter of the mesh,
  • the outer perimeter of the mesh may have any geometric shape and suitably includes outer peripheral sections that define triangular, quadrangular, pentagonal and hexagonal shapes and so forth.
  • the mesh may also have non-linear outer perimeter sections.
  • the mesh may have corners that are defined at the intersection of peripheral sections of the mesh. It is possible that the corners may be both outwardly or inwardly oriented corners.
  • the peripheral attachment regions may be located about, or close to, a peripheral edge of the mesh.
  • the peripheral attachment regions may include attachment regions located at extremities of the mesh, such as corners, herein called extremity attachment regions, and attachment regions located intermediate of the extremities of the mesh, herein called intermediate attachment regions.
  • the reinforcing elements may be arranged to interconnect at least one of the intermediate attachment regions on one side of the mesh to at least one opposite extremity attachment regions, for example, located on an opposite side of the mesh.
  • the extremity attachment regions may be arranged at one or more of corners of the mesh.
  • the intermediate attachment regions may be located between the extremities of the mesh.
  • peripheral attachment regions may be located intermediate of the corners of the mesh.
  • the attachment region of at least one extremity of the mesh, such as a corner, and the attachment region intermediate an opposite extremity, such as an opposite corner, may be interconnect by the reinforcing element.
  • the mesh may also include inner attachment regions that are disposed on the mesh inwardly from peripheral attachment regions or inwardly of an outer perimeter of the mesh.
  • the reinforcing elements extend diagonally across the mesh between the peripheral attachment regions.
  • two or more of the peripheral attachment regions may be disposed at the corners of the sheet.
  • the peripheral attachment regions may also be disposed part-way along a peripheral section between corners of the sheet.
  • One of the inner attachment regions may be disposed centrally on the mesh, for example, when only one inner attachment region is provided.
  • Multiples of the inner attachment regions may also be disposed along an axis, for example, either on an axis that bisects the sheet body, or on an axis that extends along a dimension of the sheet body such as widthwise or lenthwise axis of the sheet body.
  • the reinforcing elements may transverse between at least one inner attachment region and at least one peripheral attachment region.
  • the reinforcing elements extending between the peripheral and inner attachment regions further reduce the shearing of the mesh.
  • the attachment regions may be in the form of an opening in the mesh and the reinforcing elements, at least in part, define the opening.
  • the opening of one of the attachment regions may be defined between adjacent reinforcing elements.
  • the opening of one of the attachment regions may be defined between one of the reinforcing elements, and part of the body of the mesh defining the apertures of the open mesh.
  • the attachment regions may include a preformed opening for receiving a fastener.
  • the attachment regions may be pierced, such as by driving, punching or cutting an opening through the attachment region to accommodate a fastener.
  • the attachment regions may include a line of weakness that, when fractured, define the opening for receiving a fastener.
  • the apertures of the open mesh for venting gases and observing strata may be arranged in a pattern over at least part of the mesh.
  • the apertures which may form venting areas may also provide points for observing the strata and the term "venting area" may be referred to interchangeably as an "observing area”.
  • the pattern of apertures may be arranged across the mesh, and suitably across the entire body of the mesh, and the reinforcing elements extend
  • the apertures immediately either side the reinforcing strapping may be of different shape and size to the apertures that are not crossed by the reinforcing elements.
  • the apertures may be arranged in rows and ranks relative the perimeter of the mesh.
  • the apertures may have any geometric shape including asymmetric, circular, quadrangular and so forth.
  • the venting areas may have a regular pattern of apertures that are oriented relative to the reinforcing elements so that the reinforcing elements are flanked on opposite sides by the venting areas.
  • the apertures may be arranged in rows parallel to the reinforcing elements.
  • regular pattern may mean that the apertures in the venting area each have a constant size or formation.
  • At least one and suitably the entire venting area may define one large aperture for venting and visual inspection of the strata.
  • one or more of the venting areas may be multiple apertures for venting and visual inspection.
  • the mesh has a body made up of lengths of material such as bars, wires, webs and ribbons that are overlaid and secured at points to form an assembled mesh.
  • the apertures for venting the gases and visual inspection may be provided in the space between the lengths of material.
  • the reinforcing elements may also be lengths of material such as bars, wires, webs and ribbons arranged across the mesh so as to extend in a direction between the attachment regions.
  • the tensile strength of the mesh in the direction of the reinforcing elements is equal to, or greater than, the tensile strength of the mesh transverse to the direction of the reinforcing elements.
  • the tensile strength of the sheet in the diagonal direction between the opposite corners is at least the same as the tensile strength in the widthwise or lengthwise direction of the sheet body.
  • the mesh may have a tensile strength in the range from 30 to 250 kN per linear metre, suitably in the range from 40 to 120 kN per linear metre for heavy duty applications, and even more suitably up to 50 to 100 kN per linear metre for some applications, and still even more suitably from 50 to 80 kN per linear metre for standard applications.
  • the mesh may be sufficiently flexible so as to be rolled, and suitably rolled by hand.
  • the mesh may be in the form of discrete panels.
  • the panels can be lifted and moved into an operative position by a single person.
  • discrete panels of the mesh have weight in the range of 3 to 10 kilograms, and more suitably in the range of 4 to 8 kilograms, and even more suitably in the range of 4 to 6 kilograms.
  • the mesh may also be formed in a continuous length having lines of weakness extending across the continuous length that enable the continuous length to be broken into separate panels or sheets.
  • the continuous length may be broken into panels or sheets at any stage after manufacture.
  • the reinforcing elements increase the dimensional stability of the mesh in a direction between the openings for the anchors.
  • the reinforcing elements may have edges that have an uneven profile including a stepped profile, suitably the reinforcing elements have linear edges that extend across the apertures of the mesh so as to reinforce the apertures.
  • the reinforcing elements may include one or more curvilinear sections that are arranged diagonally between the corners. In another example, the reinforcing elements may include one or more linear sections that are arranged diagonally between the corners.
  • the mesh may be formed using any suitable technique and material including polymeric materials including thermoplastics and thermoset plastics, fibrous materials including glass fibres and carbon fibres and mineral fillers, and combinations thereof including laminates and co-extrusions.
  • the mesh may also have suitable antistatic additives and/or conductive filaments or yarns extending across the mesh and/or co-extruded layers of antistatic compounds and/or antistatic surface treatments.
  • the conductive filaments or yarns may be connected by a terminal and may be earthed to prevent the build-up of electro-static charge.
  • the mesh is suitably made of a polymeric containing materials including, but by no means limited to, acrylic, ABS, styrene, SBR, polycarbonate, and polyethylene and any combinations thereof.
  • the mesh suitably has sufficient brittleness that allows the mesh to break apart on being processed by the cutting head of a mining machine. If the mesh were to lack a sufficient level of brittleness, the mesh may tend to entangle the cutting head rather than break apart into pieces. Material that tends not to break apart can cause the mesh to foul the cutting head.
  • a suitable polymeric material having a toughness of less than 300J/m according to the American Society for Testing Materials (ASTM) is envisaged as being sufficiently brittle to allow the material to not foul the cutting head.
  • Materials having a low toughness are often characterised as also having a low modulus of elasticity.
  • the mesh may have lines of weakness or points of weakness of selected strength and position.
  • the weakness may be spaced to facilitate fragmentation of the mesh into pieces that are less likely to foul the cutting head.
  • the present invention also relates to a method of making an open mesh for supporting the walls of an underground mine, the method including the steps of:
  • Steps a) to c) may be carried out simultaneously, consecutively, or disjunctively one after the other.
  • steps a) to c) may be carried out simultaneously by extruding and thereafter quenching the polymeric material.
  • the extruding step may be preceded by a mixing step in which the polymeric materials are combined and melted into a flowable single phase.
  • the extruding step may also be carried in two or more separate sub-layers which are co-extruded, for example, to form a laminated structure.
  • one or more of steps a) to c) may include casting any one or a combination of the sheet body, the attachment regions and the reinforcing strapping.
  • the method may also involve quenching by passing the extrusion or casting between rollers, of which at least one is a cooled roller.
  • steps a) to c) may be carried out by cutting the apertures for observing strata and for venting gases into a sheet.
  • steps a) to c) may also involve cutting apertures in parts of the sheet other than the location of the reinforcing strapping interconnecting the attachment regions.
  • the method of making the mesh may also include any one or a combination of the features of the mesh described herein.
  • An embodiment of a mesh for supporting the walls of an underground mine may include a planar sheet body having an outer perimeter formed by linear peripheral sections and an array of apertures that are arranged inside the perimeter of the body, the peripheral sections being arranged such that adjacent peripheral sections form reflexes or corners about the perimeter of the body and at least one opening is provided adjacent to, or toward, each corner for receiving a fastener that can be used to anchor the mesh to a wall of the underground mine, wherein the body has at least one reinforcing section that extends from one corner to another so as to traverse cross at least part of the body and thereby reinforce the tensile strength of the mesh in a direction between the respective corners.
  • the present invention also relates to an underground mine in which the mesh, having any one of the features described herein, is anchored to the walls of the mine.
  • the mesh may be installed to the walls of the underground mine such that the peripheral attachment regions of adjacent meshes are overlaid and a single anchoring member is operative to anchor the overlaid peripheral attachment regions.
  • the mesh includes conductive threads extending across the mesh, and the conductive threads may be earthed to the walls of the mine to discharge electro-static energy.
  • a cutting head of mining machinery can excavate the wall of the mine while the mesh is on the wall on account that the mesh has a brittleness that allows the mesh to break apart on being processed by the cutting head of a mining machine.
  • Figure 1 is a plan view of a mesh for supporting the walls of an underground mine according to a preferred embodiment
  • Figure 2 is an enlarged view of a corner section of a mesh having specifically located openings for receiving a fastener according to another embodiment
  • Figure 3 is a enlarged view of a corner section of a mesh having a specifically located opening for receiving a fastener according to another embodiment
  • Figure 4 is a plan view of a mesh for supporting the walls of an underground mine according to yet another embodiment
  • Figure 5 is a plan view of a mesh for supporting the walls of an underground mine according to still yet another embodiment
  • Figure 6 is a plan view of a mesh for supporting the walls of an underground mine according to an alternative embodiment
  • Figure 7 is a block diamgram illustrating the base steps of the meth of the making the mesh
  • Figure 8 is a schematic illustration of two overlapping mesh installed to the wall of an underground mine.
  • Figure 9 is a schematic illustration of mesh installed to wall of an underground mine, including the upright and ceiling walls, and a cutting head in the process of excavating the wall having the mesh installed.
  • the mesh may be made of other suitable materials including fibre glass and other fibrous materials, and/or metallic materials including steel bars and wires that are arranged in a mesh and welded.
  • the mesh may also have a composite structure comprising two or more different forms of materials including laminated structures.
  • Figure 1 is a plan view of an integrally formed polymeric mesh 10 having a flexible sheet body 1 1 that can be rolled.
  • the mesh 10 has a rectangular outer perimeter having a length greater than its width, and apertures 14, formed by grid strapping 15, for observing the strata and for venting gas that are arranged in a grid of rows and columns over the sheet body 1 1.
  • the sheet body 1 1 also has nine attachment regions 12 (identified by a dashed circle) at which a fastener can be used for fastening the mesh 10 to the wall of an underground mine.
  • the nine attachment regions 12 include four peripheral attachment regions 12 at the corners extremities of the sheet 1 1 , two peripheral attachment regions 12 located approximately half way along the length of the perimeter of the sheet 1 1 , and three inner attachment regions 12 located along a central longitudinal axis of the sheet 1 1.
  • Reinforcing elements in the form of strapping 13 extends diagonally across the sheet 1 1 to interconnect the attachment regions 12 on opposite sides and in some instances on opposite corners. The reinforcing strapping 13 extending diagonally across the sheet increases the dimensional stability of the mesh 10 on widthwise and lengthwise axes of the mesh 10.
  • the apertures 14 are defined by a network of the grid strapping 15 arranged lengthwise and widthwise across the mesh 10 so as to define square apertures 14.
  • the reinforcing strapping 13 interconnecting the attachment regions 12 is tensioned, thereby reducing the distortion of the mesh 10 and the apertures 14 and ultimately reducing the incidence of failure of the mesh 10 compared to other non-reinforced mesh.
  • the reinforcing strapping 13 was omitted, the mesh can more easily yield, which is observed initially by the mesh and apertures distorting into a diamond shape and ultimately breaking apart.
  • the reinforcing strapping 13 of the preferred embodiment increases the tensile strength of the mesh 10 by dividing the mesh 10 into triangular subsections and providing direct and linear load bearing reinforcing strapping 13 between the attachment regions 12.
  • the overall tensile strength of the mesh 10 can be selected, for example by increasing the weight of the mesh 10, which will ultimately increase the cost of the mesh.
  • discrete panels of the mesh have a weight in the range of 3 to 8 kilograms and suitably approximately 4.6kg.
  • the mesh has reinforcing elements, i.e. strapping 13 having a width of
  • the mesh 10 may have a tensile strength in the range of 50 to 80 kN per linear metre for standard applications. However for heavy duty applications, the tensile strength of the mesh 10 can be increased up to 120 kN per linear metre by increasing the weight of the mesh 10.
  • One of the advantages of the improved tensile strength of the mesh is that deflection of the mesh in a direction transverse, and particularly normal to the surface of the mesh is able to be minimised, thereby providing the mesh with an enhance capacity to resist strata movement and have a higher failure rating.
  • the reinforcing strapping 13 extends diagonally across the mesh 10 to interconnect attachment regions 12 on opposite sides of the sheet 1 1 .
  • each attachment region 12 along the perimeter of one side of the mesh 10 is interconnected to two attachment regions 12 on an opposite side of the mesh 10.
  • the mesh includes four attachment regions 12 located at the corner extremities of the mesh, called extremity attachment regions 12e, and two attachment regions 12, located intermediate of the corner extremities, called intermediate attachment regions 12i.
  • the reinforcing strapping 13 interconnects the intermediate attachment regions 12i located in one side of the mesh, to the extremity attachment regions 12e located on the other side of the mesh.
  • reinforcing strapping 13 interconnects the extremity attachment regions 12e located on one side of the mesh, by extending diagonally across the mesh to interconnect with the extremity attachment regions 12e on the opposite side of the mesh.
  • the mesh 10 also includes three inner attachment regions 12 that lie on the reinforcing strapping 13 extends between the opposite sides of the mesh 10.
  • the attachment regions 12 may include attachment openings 16, formed between the reinforcing strapping 13 extending between the attachment regions 12.
  • the attachment openings 16 may also be formed between reinforcing strapping 13 and the grid strapping 13 which defines the open mesh.
  • attachment regions 12 may be cut, for example by drilling or piercing a hole through the attachment regions 12 for receiving a fastener.
  • the apertures 14 for visual inspection of the strata and for venting gases that are immediately adjacent to the reinforcing strapping 13 may also provide openings 16 through which a fastener can be positioned.
  • the attachment regions 12 may include an opening 16 in the mesh 10 immediately adjacent to the reinforcing strapping 13.
  • the opening 16 may also form part of the apertures 14 for observing strata and venting gases. It is also possible that the opening may be specifically formed for a fastener.
  • FIG 2 is an enlarged view of a corner of a mesh 10 according to one example in which an opening 16 for receiving a fastener is provided in an attachment region 12 as close as possible to the corner of the mesh 10.
  • the opening 16 also being provided at the ends of the reinforcing strapping 13 that extends across the mesh 10.
  • sections of the apertures 14 fall within the attachment region 12.
  • a fastener may also be placed in the apertures 14.
  • Figure 3 is an enlarged view of a corner of a mesh 10 according to another example in which the aperture 14 between two lengths of reinforcing strapping 13 has been extended toward the corner of the mesh 10.
  • the extension of the aperture 14 provides an opening 16 at one end for receiving a fastener.
  • FIG 4 is an example of another embodiment of a mesh 10 having a sheet body 1 1 with attachment regions 12 including attachment openings 16, such as those represented by dashed lines for receiving a fastener have either been preformed or made on site. It is also possible that the dashed lines may represent lines of weakness. Venting and/or observation areas defined by the apertures 14 are arranged between the peripheral sections and reinforcing strapping 13 that extends between the attachment openings 16.
  • the venting areas 14 are triangular segments that are either completely open or may include additional elements (not illustrated in Figure 4) that extend across the triangular segments that define smaller apertures within the triangular segments. The additional elements may help to arrest spalling and unravelling of the mine wall strata.
  • Figure 5 is an example of another embodiment of a mesh 10 having a sheet body 1 1 with attachment regions 12 including attachment openings 16 or points where attachment openings can be cut for receiving a fastener. Venting areas or apertures 14 are arranged between the peripheral sections 15 and the reinforcing strapping 13 that extends between the attachment openings 16.
  • Figure 6 is an example of another embodiment of a mesh 10 having a sheet body 1 1 with attachment regions 12 including openings 16 formed between two adjacent reinforcing elements 13. Venting areas or apertures 14 are arranged over the mesh 10 and the reinforcing strapping extends between the openings 16 of the attachment regions 12.
  • the mesh 10 of any one of the embodiments may be made from any suitable material and be made using any suitable technique.
  • the mesh 10 may be made from polymeric materials including, but by no means limited to any one or combination of the following constituents: acrylic, ABS (Acrylonitrile butadiene styrene), polycarbonates, styrene, SBR, and polyethylene. Suitable ratios of acrylic to ABS constituents range from 0.01 to 0.08 acrylic to 0.99 to 0.92 ABS i.e., from 2 to 8% acrylic in ABS on a weight basis.
  • the mesh 10 may also include fibrous constituents including fibre glass, carbon fibre with or without mineral fillers and so forth.
  • the polymeric material may also include any one or a combination of suitable antistatic additives (AS) or flame retardant additives (FR).
  • AS antistatic additives
  • FR flame retardant additives
  • the polymeric material itself may have inherently characteristics that are flame retardant or anti-static and in this case additives may not be required.
  • the mesh may include conductive filaments, that can be earthed, for example, via the anchoring members used to anchor the mesh to the mining walls.
  • the conductive filaments may be applied to the mesh after the mesh has been formed, for example, applied by means of adhesive.
  • the conductive filaments may be embedded in the mesh, for example, during casting or extrusion of the mesh.
  • the filaments may be any suitable conductive strand or yarn.
  • the conductive filaments may be arranged in an array of spaced apart conductive filaments extending across the mesh and be interconnect at terminal extending across two or more filaments.
  • the terminal may be earth to prevent the accumulation of static charge in the mesh.
  • the filaments of one mesh may make electrical contact with the filaments of an adjacent mesh. Electrical connection may, for example, be provided by an electrical coupling the couples together terminals or individual filaments of the mesh.
  • the mesh may also have a monitor for monitoring conductivity of one or more of the filaments, or all of the filaments, across the mesh.
  • the monitor may include a Volt meter or Amp meter. In the event that conductivity is lost, the mesh may have partially or completely failed.
  • a characteristic of the improved mesh 10 is that it has a high tensile strength for its given mass which is largely attributable to the configuration of the reinforcing strapping 13 between the attachment regions 12.
  • the material selection also contributes to economic manufacture and the tensile strength of the mesh 10.
  • the reinforcing strapping 13 extending between the attachment regions 12 can help resist the mesh from elongating, deformation or failing.
  • Another desirable characteristic of the mesh is that while the mesh offers tensile strength, the mesh is relatively brittle so that the mesh can break apart on being processed by the cutting head of a mining machine.
  • the brittleness of the mesh is often measured in terms of toughness or modulus of elasticity. Materials having a lower toughness are more brittle than materials having a higher toughness.
  • a test sample of the mesh 10 having dimensions of 63.5mm by 12.7mm by 3.2mm has been measured as having an Izod impact strength of the less than 300J/m.
  • the mesh 10 may be made using any suitable technique including extrusion of a polymeric blend or co-extrusion in which multiple layers of compatible material, particularly polymeric materials are layered one on top of the other.
  • the mesh may be made by cutting sections from a complete continuous sheet so as to form the required apertures 14 for observing the strata and venting gas yet provide the mesh with an ability to hold loose strata fragments, and reinforcing strapping 13 between the attachment regions 12 for fastening the mesh 10 to the strata of an underground mine.
  • FIG. 7 is a block diagram illustrating method steps for making the mesh including the following.
  • the sheet body may for example, be cast or extruded, and the apertures may be formed during the casting or extrusion step, or subsequently cut into the sheet body.
  • attachment regions in the mesh that are adpated to allow a fastener to operably secure the mesh to the walls of a mine.
  • the attachments regions may be fitted to the sheet, but suitably, simultaneously formed during formation of the body of the mesh.
  • FIG 8 is a schematic illustration showing two discrete mesh panels 10 secured in overlapping relationship to the wall 20 of an underground mine 23. As can be seen, the mesh 10 are overlapped so that peripheral attachment regions 12e of the two mesh 10 are aligned and a single anchoring member 21 operably secures the adjacent mesh 10 in position. Further anchoring members 21 can be fitted depending on the load of the mesh, including, as a minimum, anchoring members 21 at the opposite corners of each mesh 12e.
  • FIG 9 is a schematic side view of an underground mine 23 having four mesh panels 10 secured to the wall 20 to reduce the risk of the strata falling.
  • adjacent sections of the mesh 10 are overlapped, and suitable anchors 21 , such as rock bolts with large heads or washers are used to secure the mesh 10 to the wall 20.
  • suitable anchors 21 such as rock bolts with large heads or washers are used to secure the mesh 10 to the wall 20.
  • the mesh 10 is made of brittle polymeric material, as described above, the mesh 10 can remain in position on the wall 20 while a cutting head 22 of an excavator is operated. The cutting head 22 destroys the mesh 10 as it contacts the mesh 10 and excavates the wall 20.
  • the mesh 10 is formulated to break into pieces to reduce the risk of the mesh becoming entangled on the cutting head.
  • the grid strapping may be arranged at a 45 degree angle to the perimeter of the mesh so as to form an open mesh having a diamond pattern.
  • the reinforcing strapping will extend in the same direction or parallel to straps of the grid pattern.
  • the reinforcing elements will have greater tensile strength than the straps defining the grid pattern.
  • the mesh may be pre-curved in a widthwise or lengthwise direction.
  • the mesh may have a convex face which is located against the wall of the mine, and during installation, the anchoring members may tension the mesh, for example by flattening the mesh so that the body of the mesh applies pressure and supports to the mine walls. In this instance, the positive pressure applied bu the mesh helps to prevent fragments of the mine walls from falling.

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  • Engineering & Computer Science (AREA)
  • Mining & Mineral Resources (AREA)
  • Architecture (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Geology (AREA)
  • Lining And Supports For Tunnels (AREA)

Abstract

La présente invention concerne un treillis, un procédé de fabrication du treillis et une mine souterraine dans laquelle le treillis a été utilisé pour soutenir les parois de l'exploitation minière. Idéalement, le treillis est un treillis ouvert ayant des éléments de renfort qui interconnectent une région de fixation pour augmenter la résistance à la traction du treillis dans une direction entre les régions de fixation.
PCT/AU2013/000601 2012-06-06 2013-06-06 Treillis et procédé de fabrication du treillis WO2013181706A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
AU2012902371 2012-06-06
AU2012902371A AU2012902371A0 (en) 2012-06-06 Mesh and method of making the mesh
US201261657175P 2012-06-08 2012-06-08
US61/657,175 2012-06-08

Publications (1)

Publication Number Publication Date
WO2013181706A1 true WO2013181706A1 (fr) 2013-12-12

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2016181281A1 (fr) * 2015-05-08 2016-11-17 Nicaud Companies 22 (Pty) Ltd Filet de sécurité
CN107100665A (zh) * 2017-06-09 2017-08-29 西安科技大学 一种基于矿井瓦斯治理设计的煤层气抽采间接经济效益评价方法
WO2018023161A1 (fr) * 2016-08-02 2018-02-08 Corex Plastics (Australia) Pty Ltd Feuille de polymère, son procédé d'installation et de production
CN113513331A (zh) * 2021-04-15 2021-10-19 上海交通大学 基于盾构机运行参数的掘进掌子面岩土类型识别方法、系统及介质

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WO2009006692A1 (fr) * 2007-07-09 2009-01-15 The University Of Western Australia Système de maille
WO2011136656A1 (fr) * 2010-04-27 2011-11-03 John Oldroyd Cheetham Membrane ignifuge stratifiée et procédé pour sa fabrication

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WO2008087537A2 (fr) * 2007-01-18 2008-07-24 Skarboevig Nils Mittet Filet de soutènement destiné à des soutènements souterrains pour mines
WO2009006692A1 (fr) * 2007-07-09 2009-01-15 The University Of Western Australia Système de maille
WO2011136656A1 (fr) * 2010-04-27 2011-11-03 John Oldroyd Cheetham Membrane ignifuge stratifiée et procédé pour sa fabrication

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2016181281A1 (fr) * 2015-05-08 2016-11-17 Nicaud Companies 22 (Pty) Ltd Filet de sécurité
WO2018023161A1 (fr) * 2016-08-02 2018-02-08 Corex Plastics (Australia) Pty Ltd Feuille de polymère, son procédé d'installation et de production
CN110023587A (zh) * 2016-08-02 2019-07-16 克热斯塑料(澳大利亚)私人有限公司 聚合物薄片及其安装和制备方法
US11078789B2 (en) 2016-08-02 2021-08-03 Corex Plastics (Australia) Pty Ltd Polymer sheet, method of installing and producing same
CN110023587B (zh) * 2016-08-02 2022-04-15 克热斯塑料(澳大利亚)私人有限公司 聚合物薄片及其安装和制备方法
US11624280B2 (en) 2016-08-02 2023-04-11 Corex Plastices (Australia) Pty Ltd Polymer sheet, method of installing and producing same
CN107100665A (zh) * 2017-06-09 2017-08-29 西安科技大学 一种基于矿井瓦斯治理设计的煤层气抽采间接经济效益评价方法
CN113513331A (zh) * 2021-04-15 2021-10-19 上海交通大学 基于盾构机运行参数的掘进掌子面岩土类型识别方法、系统及介质

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