S&F Ref: 858987 AUSTRALIA PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT Name and Address NV Bekaert SA, of Bekaertstraat 2 Zwevegem, B-8550, of Applicant : Belgium Actual Inventor(s): Hector Paredes Montecinos Address for Service: Spruson & Ferguson St Martins Tower Level 35 31 Market Street Sydney NSW 2000 (CCN 3710000177) Invention Title: High-carbon chain link fence for mining industry The following statement is a full description of this invention, including the best method of performing it known to me/us: 5845c(1 243250_1) 1 HIGH-CARBON CHAIN LINK FENCE FOR MINING INDUSTRY Field of the Invention The present invention relates to a chain link type fence. The present invention 5 also relates to the use of a chain link type fence in the mining industry, such as in a mining tunnel. Background of the Invention A chain link fence is perhaps the most economical type of fencing available. A 1o conventional chain link fence is usually made of plain low carbon steel that has a carbon content of 0.15 per cent by weight or lower. The following types of chain link fence are common: a chain link fence with meshes having a square form with a size of 100 mm x 100 mm, formed by a steel wire having a diameter of 5.10 mm; is a chain link fence with meshes having a square form with a size of 50 mm x 50 mm, formed by a steel wire having a diameter of 4.20 mm. These existing conventional chain link fence types are widely used but have the following drawbacks: the chain link fences have a relatively high weight and hence are difficult to 20 manipulate; the chain link fences are made with thick steel wire having a relatively large diameter, which results in thick meshes; the chain link fences have a relatively low strength. When used in the mining industry, these existing conventional chain link fences 25 may not provide a sufficient reinforcement, as illustrated by FIGURE 1. FIGURE 1 shows a prior art chain link fence 10 reinforcing the ceiling 12 of a mine. Due to the low strength of chain link fence 10, this fence 10 is not able to maintain the integrity of the ceiling 12 and hold stone material 14 for a sufficiently long period of 30 time. Because of the weakness of the chain link fence 10, the fence 10 fails at its weakest spot and the stone material 14 pours down into the mine. US patent US-A-2,188,869 discloses a so-called high-carbon fence. The exact carbon content, however, is not mentioned. Nor is the disclosed fence a chain link fence.
2 Furthermore, the applications mentioned in US '869 are not tunneling applications, such as in mining, and do not use shotcrete. German utility model DE-U-296 06 610 discloses a hexagonal mesh for use in tunnels and mining. However, the utility model is silent with respect to the carbon 5 content of the mesh. Object of the Invention It is the object of the present invention to substantially overcome or ameliorate one or more of the disadvantages of the prior art. 10 Summary of the Invention One aspect of the present invention provides a mine tunnel chain link fence to reinforce the tunnel, said chain link fence having a plurality of steel wires, each wire having a carbon content ranging from 0.45 to 0.57% by weight and a diameter ranging is from 3.5 to 4.0 mm. Another aspect of the present invention provides a method of reinforcing a mine tunnel, the method including the steps of: providing a chain link fence having a plurality of steel wires, each wire having a carbon content ranging from 0.45 to 0.75% by weight and a diameter ranging from 3.5 to 20 4.0 mm; and placing the chain link fence along a ceiling between two side walls in the tunnel. Brief Description of the Drawings Preferred embodiments of the invention will be described hereinafter, by way of 25 examples only, with reference to the accompanying drawings. FIGURE 1 illustrates a failure mode of a prior art chain link fence; FIGURE 2 illustrates a chain link fence in a mining tunnel, according to an embodiment; FIGURE 3 illustrates a chain link fence in a mining tunnel, according to an 30 embodiment; FIGURE 4 is a top view of a testing configuration for a chain link fence, according to an embodiment; and FIGURE 5 is a side view of the testing configuration of FIGURE 4.
3 Detailed Description The present invention relates to a chain link fence. The fence can be used in the mining industry, such as in tunneling and shotcrete applications. Aspects of the present invention include: (1) lowering the weight of chain link fences, (2) facilitating the 5 manipulation and installation of chain link fences, (3) lowering the thickness of a chain link mesh, and (4) increasing the strength and breaking load of a chain link mesh. According to an embodiment, a chain link fence can be made of steel wires having a steel composition with a carbon content of 0.45 per cent by weight or more. For example, a chain link fence can be made of steel wires having a steel composition with a 10 carbon content of 0.45 to 0.70 per cent by weight. In another example, a chain link fence can be made of steel wires having a steel composition with a carbon content of 0.45 to 0.57 per cent by weight. In another example, a chain link fence can be made of steel wires having a steel composition with a carbon content of 0.45 to 0.55 per cent by weight. In another example, a chain link fence can be made of steel wires having a steel is composition that corresponds to SAE 1050. According to an embodiment, a chain link fence can be made with meshes that have a square form of Y mm x Y mm. For example, Y can range from about 60 mm to about 90 mm. In another example, Y can range from about 65 mm to about 85 mm. In another example, Y can range from about 70 mm to about 80 mm. In another example, Y 20 can be about 75 mm. According to an embodiment, a chain link fence can be made from steel wires having a relatively small diameter. For example, a chain link fence can be made from steel wires that have a diameter of about 4.0 mm or less. In another example, a chain link fence can be made from steel wires that have a diameter of about 3.00 mm to about 4.00 25 mm. In another example, a chain link fence can be made from steel wires that have a diameter of about 3.25 mm to about 4.00 mm. In another example, a chain link fence can be made from steel wires that have a diameter of about 3.50 mm to about 4.00 mm. In another example, a chain link fence can be made from steel wires that have a diameter of about 3.50 mm to about 3.80 mm. 30 In another example, a chain link fence can be made from steel wires having a diameter of 3.66 mm and a composition corresponding to SAE 1050 to form a chain link fence with mesh squares having a size of 75 mm. Such a chain link fence weighs 2.5 kg /
M
2 . In contrast, a 10006 fence, which is a fence with a mesh size of 100 mm x 100 mm made from wire having a diameter 5.10 mm, would weigh 3.5 kg / M 2 . Furthermore, a 4 5008 fence, which is a fence with a mesh size of 50 mm x 50 mm made from wire having a diameter of 4.20 mm, would weigh 4.8 kg / in 2 . A chain link fence arranged according to the embodiments and examples described herein can have a lower weight per square meter. By using smaller diameter s wire, a chain link fence can be provided with a lower thickness and weight. Furthermore, because the chain link fence has a relatively lower thickness, the chain link fence has a relatively high flexibility and can be more easily formed. By using wires made from a steel composition with a relatively high carbon content, the chain link fence can have an increased strength, such as tensile strength, and higher breaking load, despite the use of io steel wires with a relatively small diameter. Thus, because the chain link fence is lighter and thinner, such a chain link fence can be easily manipulated and installed while providing a chain link fence with an increased strength and breaking load. A further advantage of a chain link fence arranged according to the embodiments and examples described herein is that less material, such as projected concrete or 15 shotcrete, needs to be used because the fence is thinner. This provides a savings in cost due to the decreased use of materials. According to an embodiment, a tunnel can be reinforced by a chain link fence that is configured according to any of the embodiments and examples described herein. According to an embodiment, a method of using a chain link fence to reinforce a 20 tunnel can be practiced by providing a chain link fence according to any of the embodiments and examples described herein and reinforcing the tunnel with the chain link fence. FIGURE 2 illustrates a chain link fence 20 that is used in a mine 22, according to an embodiment. For example, the chain link fence 20 can be used to reinforce the ceiling 25 and/or wall of a tunnel in the mine 22. In the example of FIGURE 2, the chain link fence 20 is used to reinforce a ceiling about two side walls of a tunnel in a mine 22 in front of an open end of the tunnel. FIGURE 3 illustrates a chain link fence 30 that is used in a mine 32, according to an embodiment. For example, chain link fence 32 can be used to reinforce the ceiling 30 and/or wall of a tunnel in the mine 32. In the example of FIGURE 2, the chain link fence 30 is used to reinforce a ceiling about two side walls of a tunnel in a mine 32 in front of an open end of the tunnel. FIGURE 4 is a top view of a testing configuration for a chain link fence, according to an embodiment. As shown in the example of FIGURE 4, a chain link fence 35 40 can be connected to a testing frame 42 and a localized load 50 can be applied to a 5 center 44 of the fence 40. The tested chain link fence 40 can be a 1 m x I m sample that is fixed to the testing frame 42. The test can be arranged to simulate a load of rocks, such as a fence would be loaded with in an underground mine. FIGURE 5 is a side view of the testing configuration of FIGURE 4. As shown in 5 the example of FIGURE 5, the displacement of the fence 40 caused by the load 50 can be measured, along with the amount of the load 50 itself. Conventional fences, such as chain link fences made out of 5.10 mm diameter low carbon wire that form square meshes with a size of 100 mm, have breaking loads that typically range from 3.8 tons to 5.1 tons. 10 An example of a chain link fence made out of steel wire with a composition corresponding to SAE 1050 with a diameter of 3.76 mm that form square meshes with a size of 75 mm have breaking loads that range from 4.9 tons to 6.2 tons. The foregoing description of embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit is the invention to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of the invention. The embodiments were chosen and described in order to explain the principals of the invention and its practical application to enable one skilled in the art to utilize the invention in various embodiments and with various modifications as are suited to the 20 particular use contemplated. Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein.