Field of the Invention

The present invention relates to safety systems for preventing workers from falling off an elevated area. Particularly preferred embodiments of the present invention advantageously protect workers from falling of the edge of a bench in an open cut mine. The present invention may also find application in other environments where workers are required to occupy elevated work sites including rail duplication, plant expansion, heavy equipment, road works, pit extensions, lookouts and in safety applications in general. Background To The Invention

The edge of a bench in an open cut mine may extend downwardly by 2 to 25 meters or more. This presents several risks including the possibility of a worker falling off the edge and being severely injured. In an open cut mine such risks are typically managed by operational procedures and delineation. One method of providing safety near the edge of a bench of an open cut mine involves extending a safety line between two posts fixed in the ground at positions spaced a set distance away from the edge. Each worker is required to wear a harnesses system having a cable, such as a retractable cable, that is clipped to the safety line. Should a worker wearing such a harness system slip or trip near the edge, the cable will pull against the safety line to restrain and limit the extent of any fall.

With safety line systems the ability of workers to move in a given space is often hampered by other workers connected to the safety line. Safety lines can become entangled and workers regularly have to unclip from the safety line. It is also sometimes the case that vehicles or other equipment may need to be moved about the workspace and may need to pass the safety line(s). This can cause further complications including delaying general working operations.

It is against this background and the problems and difficulties associated therewith that the present invention has been developed. Any material discussed or otherwise disclosed in the present specification is intended to explain the context of the invention. It is not to be taken as an admission that the material formed part of the prior art base or relevant general knowledge in any particular country or region.

Disclosure Of The Invention According to a first aspect of preferred embodiments herein described there is provided a safety system for preventing workers falling off the edge of an elevated area, the system including: a plurality of post arrangements for use in securing a barrier; and a plurality of base members; wherein each post arrangement has a first portion for being removably received in the ground through a respective base member; and at least one of the base members is adapted to hold a first portion of a corresponding post arrangement in a fixed rotational position.

The safety system is preferably an advantageous safety system for preventing workers falling off the edge of a bench in an open cut mine or some other relatively hard surface. In these arrangements the first portions are preferably adapted to be received in predrilled holes in the surface e.g. bench.

The system may be adapted to be readily erected and removed, as required. This flexibility in the erection and removal of the system allows the system to be fitted to different sized and shaped work spaces. For example, when the system is fitted to a bench, the system can accommodate their characteristic irregular shaped edges.

The base members may include a support portion for lying on the surface of the ground and a location portion for extending into the ground. The location portions may each comprise a cylindrical portion having a passage that extends through the support portion and which provides an opening for receiving a respective first portion of one of the post arrangements.

Preferably each post arrangement has a second portion for being positioned above the ground and a flange disposed between its first and second portions for engaging a support portion of a respective base member. At least some of the base members are preferably adapted to prevent relative rotational movement of post arrangements received thereby. Preferably, the base members are themselves prevented from rotation relative to the ground. This may be achieved by releasibly fixing the base members to the ground. Whilst the base members may be fixed to the ground in a number of ways including through the use of fixing members that contact the base member and the ground to fix the base member in place. The base members may also be prevented from rotational movement relative to the ground by connecting at least two base members together. For example, at least two holes can be formed, one for each of the base members, and those holes can be used to prevent the rotation of the base members. In one arrangement this may be achieved by locating a first base member in a first hole and locating a second base member in an adjacent hole. The second base member can then be connected to the first base member which can then receive a post arrangement, with the connection between the first and second base members serving to prevent rotation of the first base member having the post arrangement received therein.

Preferably at least one of the post arrangements is a tensioning post arrangement having a tensioning mechanism adapted to move the second portion of the tensioning post arrangement from a first position to a second position, relative to the ground, to place a respective barrier in tension. Preferably the tension is relatively evenly distributed along a substantial portion of the full height of the barrier. By virtue of the tension being relatively evenly distributed along a substantial portion of the full height of the barrier, the barrier is preferably less likely to be damaged in comparison to systems that use tethers or guy ropes to tension the barrier. Preferred arrangements of this form are considered to be reliable and to be relatively quickly installed, especially as tethers do not need to be anchored to the ground to tension the barriers.

In some arrangements the tensioning mechanism is preferably adapted to rotate the second portion of the tensioning post arrangement about the longitudinal axis of the tensioning post arrangement.

The tensioning mechanism may also include a locking arrangement for locking the second portion in the second position. Preferably the safety system includes a securing arrangement having one or more holes for padlocks to secure the barrier in position on the second portion.

Each barrier is preferably greater than 1 m in height. In further arrangements the barrier is preferably between 1 and 1.6m in height. According to a second aspect of preferred embodiments described herein there is provided a post arrangement for a safety system comprising: a first portion for extending into the ground; and a second portion for engaging a barrier above the ground; wherein the post arrangement further includes a tensioning mechanism for moving the second portion of the post arrangement between a first position and a second position to tension the barrier.

Preferably the tensioning mechanism is adapted to rotate the second portion about a longitudinal axis of the post arrangement. The post arrangement may include a third portion for engaging a second barrier.

According to a third aspect of preferred embodiments herein described there is provided a safety system including: a plurality of post arrangements each having a first portion for being secured in the ground and a second portion for being positioned above the ground; the safety system further including at least one barrier for extending between the post arrangements; wherein at least one of the post arrangements is a tensioning post arrangement having a tensioning mechanism, the tensioning mechanism being adapted to move the second portion of the tensioning post arrangement from a first position to a second position, relative to the ground, to place a respective barrier in tension.

Preferably the tension is relatively evenly distributed along a substantial portion of the full height of the respective barrier. According to a fourth aspect of preferred embodiments herein described there is provided a method of providing a safety system comprising: drilling a plurality of spaced apart holes in the ground; removably inserting post arrangements into the holes; and connecting barriers to securing portions of the post arrangements so that the barriers extend between the post arrangements; the method further including preventing rotational movement of at least one of the post arrangements relative to the ground. Preferably the method includes fitting base members into the holes and inserting elongate portions of the post arrangements therethrough. Preferably one or more of the of the base members is prevented from rotating relative to the ground and is adapted to prevent rotation of respective post arrangements. In yet further embodiment the method preferably includes moving at least one of the securing portions relative to the ground to tension the barriers.

Preferably the method includes locking the securing portions in position so that the barriers are protected against unauthorised removal.

In providing the safety barrier the method may include providing a safety line between two further post arrangements; and using one or more harness systems to connect one or more workers to the safety line to allow the workers to provide the safety system near the edge of an elevated area. This method is particularly useful for installing the safety system of the present invention. Once the system is installed the safety line and further post arrangements can be removed. According to a fifth aspect of preferred embodiments herein described there is provided a safety system for preventing workers falling off the edge of an elevated area including: a plurality of post arrangements and at least one barrier for extending between the post arrangements; wherein the safety system is readily erected and removed, as required, with each post arrangement having a first portion for being removably received in the ground and a second portion for being positioned above the ground.

Base members in the form of collars are preferably used to receive the first portions of the post arrangements and to hold the post arrangements in position with the first portions extending through the base members and into the ground. Preferred embodiments of the present invention are considered to provide a number of advantageous arrangements including:

(i) Systems and methods that assist with preventing workers falling off elevated work spaces such as the edge of a bench in an open cut mine; (ii) Systems and methods that provide a safety system for elevated work spaces such as an open cut mine which is relatively easy to install and which can be readily removed when no longer required;

(iii) Systems and methods that allow for a safety barrier to be readily tensioned without damaging the barrier;

(iv) System and methods that readily allow a post arrangement to be fixed in a desired position relative to the ground with the portion of the post arrangement extending into the ground being rotationally fixed in position.

(v) Systems and methods that are modular in nature and which allow a safety barrier to be provided for a range of different elevated work spaces such as open cut mine benches;

(vi) Systems and methods that are able to be used on the edges of elevated work spaces having corners that would otherwise prevent a safety barrier from being effectively installed; and (vii) Systems and methods that allow a safety barrier to be secured and which cannot be readily disassembled without authorisation.

It is to be recognised that other aspects, preferred forms and advantages of the present invention will be apparent from the specification including the detailed description, drawings and claims provided below. Brief Description Of Drawings

In order to facilitate a better understanding of the present invention, several preferred embodiments will now be described with reference to the accompanying drawings, in which:

Figure 1 is an illustrative perspective view of a safety system according to a first preferred embodiment of the present invention;

Figure 2 is illustrative front view of the safety system shown in Figure 1 ; Figure 3 is schematic front view of the safety system shown in Figure 1 ; Figure 4 provides several schematic views of a terminal post arrangement used in the safety system show in Figure 1 ; Figure 5 is a schematic view of a portion of the terminal post arrangement shown in Figure 4;

Figure 6 provides several schematic views of an idler post arrangement used in the safety system show in Figure 1 ; Figure 7 provides several schematic views of a terminal tensioning post arrangement used in the safety system shown in Figure 1 ;

Figure 8 provides several schematic views of a general tensioning post arrangement used in the safety system shown in Figure 1 ;

Figure 9 is an illustrative view of a method according to a second preferred embodiment of the present invention;

Figure 10 is a schematic perspective view of a safety system according to a fourth preferred embodiment of the present invention;

Figure 11 provides several schematic views of a post arrangement according to a fifth preferred embodiment of the present invention; Figure 12 provides several schematic views of a post arrangement according to a sixth preferred embodiment of the present invention; and

Figures 13 to 16 provide several schematic views of further embodiments according to the present invention.

Detailed Description Of The Drawings Referring to Figures 1 and 2 there is shown a safety system 10 for an open cut mine according to a first preferred embodiment of the present invention. The safety system 10 advantageously serves to limit the risk of a worker falling off an edge 12 of a bench 14 in the open cut mine. As shown in Figure 1 the terrain adjacent the edge 12 is uneven and loose and increases the risk of slipping or tripping in everyday use. A worker falling from the edge 12 would tumble about 5m and could be seriously injured. Advantageously the safety system can be readily erected and removed, as required. In an open cut mining environment these elements of the safety system 10 are considered to be particularly advantageous. As shown in Figure 1 , the safety system 10 includes five post arrangements 16 and two barriers 18. Each of the barriers 18 extends between two post arrangements 16 and includes an additional post arrangement 16 towards the middle of this span. Each barrier 18 is of a substantial height 20. In this embodiment the height of the barriers 18 is about 1.4m. This is considered to be sufficient to advantageously limit the risk of a person falling over the edge 12. This risk of course varies with rock type, gradient, climate and weather conditions.

As shown in Figure 3, several different types of post arrangement 16 are used in the safety system 10. At a first end 22 of the safety system 10 there is provided a terminal post arrangement 24. Midway along each barrier 18 there is provided an idler post arrangement 26. At an opposite end 28 of the safety system 10 there is provided a terminal tensioning post arrangement 30. Between the two barriers 18 there is provided a general tensioning post arrangement 32.

Each of the post arrangements 16 has a first portion 34 for being secured in the ground and a second portion 36 for extending above the ground. The first portions 34 are advantageously each about 1.4m in length. This serves to advantageous engage the ground and provide for a load bearing capacity of about 500 kilograms of force. The second portions 36 are each about 1.5m in length. This advantageously serves to provide a firm support for the barriers 18.

In this embodiment the barriers 18 include a first barrier 35 that extends between the terminal post arrangement 24 and the general tensioning post arrangement 32. A second barrier 37 extends between the general tensioning post arrangement 32 and the terminal tensioning post arrangement 30. The barrier 35 and the barrier 37 are both made of polyester webbing having a width of about 50mm and thickness of about 2mm. The barrier 35 and the barrier 37 are both about 10m in length, about 1.4m in depth and have a webbing spacing of about 200mm. Being about 10m in length both the width and height of the barriers 35, 37 is substantial in that the barriers provide a net for restraining at least a person of average height.

Figure 4 illustrates the terminal post arrangement 24 located at the end 22 of the safety system 10. As shown in Figure 4, the first portion 34 of the terminal post arrangement 24 comprises an elongate member 38. The second portion 36 extends upwardly from the first portion 34 and comprises an elongate member 40 and a securing portion 42.

The elongate member 38 and elongate member 40 form a post 43. In the embodiment, the securing portion 42 comprises an attachment 44 and a member 46. The attachment 44 is used to secure the member 46 in position on the post 43 so as to extend parallel to the elongate member 40. The member 46 comprises a single rod element sized to receive a number of attachment portions 48 of the barrier 35 provided in the form of several loops. The securing portion 42 holds the first barrier 35 in position on the terminal post arrangement 24. As shown in Figure 4, the terminal post arrangement 24 passes through a base member 50. The base member 50 includes an upper plate 51 in the form of a flange 52. The upper plate 51 is disposed above a lower plate 54 for being positioned on the ground.

A cylindrical portion 56 of the base member 50 is sized to be received in a hole drilled into the bench adjacent the edge. The cylindrical portion 56 serves to protect the ground from damage and to assist with holding the elongate member 38 in a vertical position. The flange 52 cooperates with a flange 58 of the post 43 and selectively allows the post 43 to rotate about its longitudinal axis.

The flange 58 forms part of the post 43 and is provided between the first portion 38 and the second portion 43. The flange 58 includes an engagement hole 60 for receiving an end 62 of the securing portion 42. In order to allow the flange 58 to rotate about the base member 50, the end 62 of the securing portion 42 does not engage the base member 50. This can be advantageous in some circumstances such as where the base member 50 is not able to be rotated. In other arrangements the end 62 of the securing portion 42 extends into one of a number of holes 61 in the base member 50 to secure the securing portion 42 in position.

In the arrangement the base 50 may also be fixed.

As shown in Figure 5, an upper portion 64 of the attachment 44 forms part of a locking arrangement 66 that allows the barrier 35 to be selectively locked in place on the second portion 36. The locking arrangement 66 includes an end 68 of the second portion 36. The end 68 includes a locking hole 70 for receiving a padlock 72. The locking arrangement 66 is considered to be advantageous for the reason that the barrier 35 can only be removed by lifting the terminal post arrangement 24 fully out of the ground. When a number of padlocks are used on each of the post arrangements 16, removing the barriers becomes very difficult. Referring to Figure 6 there is shown one of the idler post arrangements 26. The idler post arrangement 26 shown includes an elongate post member 76. The post member 76 includes a first portion 78 and a second portion 80. The post member 76 includes a flange 82 located between the first portion 78 and the second portion 80. The post member 76 further includes a first mount 84 and a second mount 86 for holding the barrier 35 in position in the vicinity of the post arrangement 26.

Two engagement elements 90 in the form of carabineers are used to hold the barrier 35 to the mounts 84, 86. In this manner, should a person fall against the barrier 35 the carabineers 90 will ensure that the post 76 restrains movement of the barrier 35 with the first portion 78 of the post 76 firmly engaging the ground.

The idler post arrangement 26 includes a base member 92. The base member 92 includes a lower plate 94 and an upper flange 96. A cylindrical portion 98 of the base member 92 is provided for being inserted into a hole drilled in the ground. When the cylindrical portion 98 is positioned in the hole, the plate 94 rests on the surface of the ground and provides a stabilising action. The cylindrical portion 98 protects the hole from damage.

An opening 99 in the flange 96 of the base member 92 allows the first portion 78 to be inserted therethrough to a depth of about 1.3m. The post 43 is held in position by the flange portion 82 of the idler post bearing against the flange 96 of the base member 92.

Advantageously the idler post arrangement 26 allows the safety system 10 to accommodate bends and corners of edges of a bench in an open cut mine. In such a case the idler post arrangement 26 is offset from the position shown in Figure 3 with the barrier 35 being pushed or pulled by the post 76. The idler post arrangement 26 also allows for the tensioning of the barrier 35 to be optimised over longer spans. In particular arrangements it is advantageous to lock the post 76 to the base 92. In the present arrangement this is achieved by using a padlock 99 that extends through holes in the flange 82 and the flange 96.

Figure 7 illustrates the terminal tensioning post arrangement 30 located at the end 28 of the safety system 10. The terminal tensioning post arrangement 30 includes a post 100. The post 100 includes a first portion 102 and a second portion 104. A flange 106 is located therebetween.

The terminal tensioning post arrangement 30 further includes a base element 108 that is adapted to be placed on the ground and to receive the first portion 102. The base member 108 includes a lower plate 1 10 and an upper plate 1 12. Between the lower plate 1 10 and the upper plate 1 12 there are provided a plurality of locating portions 1 14.

The locating portions 1 14 are each provided as an upright plate having a locating hole 1 18 therein. The base member 108 further includes a portion 120 configured to be inserted into a hole drilled in the ground. The upper plate 1 12 and portion 120 include an opening 122 that allows the first portion 102 to be inserted through the base member 108 and the portion 120 into the ground to an advantageous depth of about 1.3m.

The second portion 104 includes a securing member 124 that is adapted to secure the barrier 37 by engaging fixing portions 126 thereof. The securing member 124 forms part of a tensioning mechanism 128 that is adapted to move the securing member 124 from a first position to a second position, relative to the ground.

The upper plate 1 12 of the base member 108 includes a plurality of locking portions in the form of holes 1 16 that advantageously serve to receive the second portion 124 in position. By moving the securing member 124 the barrier 37 can advantageously be placed in tension with the tension being relatively evenly distributed along a substantial portion of the full height of the barrier 37.

This is considered to be particularly advantageous in comparison to having to use tethers or guy ropes to pull upper and lower corners of the barrier 37. With such systems it is often difficult to apply a firm tension without overloading and damaging the barrier. With the present arrangement the tension is advantageously relatively evenly distributed along almost the full height of the barrier 37.

To hold the second portion 124 in position, the flange 106 includes a locating element 132 in the form of a locating hole 130. The locating hole 130 is provided to receive an end 131 of the securing portion 124. The end 131 is configured to extend through the locating hole 130 into one of the locking portions in the form of holes 116.

The second portion 104 includes a locating element 134 in the form of a locating ring 136 at an end 137 of the second portion 104. The locating ring 136 provides an annular abutment 138 and two lugs 140. The securing member 124 includes an abutment plate 142 and a rod 144. The rod 144 includes a base member engaging portion 146 in the form of a shouldered portion at the end 131. As discussed the end 131 extends through the locating hole 130 to engage a holes of the locking portions 116.

The terminal tension post arrangement 30 is assembled by placing the portion 120 of the base member 108 into a predrilled hole of about 1.4m in depth. Following this the first portion 102 of the post 100 is inserted through the opening 122 in the base member 108. The rod 144 of the securing portion 124 is then extended through the fixing portions 126 to engage the barrier 37. The abutment plate 142 of the securing portion 124 is then placed over the end 137 of the second portion 104. To secure the barrier 37 in place, the base engaging portion 146 is then inserted through the locating hole 130 in the flange 106 to engage one of the locking portions 116. As this occurs, two recesses 154 in the abutment plate 142 engage with the two lugs 140 on the end 137 of the second portion 104. The abutment plate 142 is then forced to bear against the annular abutment 138 and is fixed in position by the lugs 140.

The terminal tensioning post arrangement 30 further includes a base member 156 which together with the base member 108 forms a base 158. The base 158 is advantageously adapted to resist rotational movement of the base element 108, relative to the ground.

The base element 156 includes a portion 160 for being inserted into a hole drilled in the ground. The base element 156 includes a locating portion 162 having a locating hole 164. The base element 156 further includes a locating portion 166 having two locating holes 168.

To install the base 158, two holes are drilled in the ground. Following this the portion 120 of the base element 108 and the portion 160 of the base element 156 are respectively positioned therein. A connection element 170 in the form of a rod is then inserted through the locating holes 168 (in the locating portion 166 of the base element 156), the location hole 164 (in the locating portion 162 of the base element 156) and one of the locating holes 114 (in the locating portion 1 14 of the base element 108). This serves to hold the base element 108 in position and prevent the base element 108 from being able to rotate about its longitudinal axis.

At the end 137, the second portion 104 includes a handle engaging portion 150 for a handle 152. The handle 152 fits onto the handle engaging portion 150 and is fixed with a pin and padlock 153, as shown, to complete the tensioning mechanism 128. The tensioning mechanism 128 is operated by slightly lifting the abutment plate 142 so that the end 146 of the securing member 124 lifts out of one of the holes 116 in the base element 108. The handle 152 is then rotated to cause the second portion 104 with the securing member 124 to rotate to a second position. This causes the securing member 124 to pull against the fixing portions 126 of the barrier 37 and for the barrier 37 to be placed in tension with the tension being relatively evenly distributed along a substantial portion of the full height of the barrier 37. When the barrier 37 is desirably tensioned, the abutment plate 142 is dropped so that the end 146 of the securing member 124 falls into another one of the holes 1 16 allowing the handle 152 to be released by the operator. The terminal tensioning post arrangement 30 is advantageous in that no guy ropes or tethers are required. As described, the post 100 is advantageously rotated about its longitudinal axis to tension the barrier 37. If the length of the barrier is significantly longer than required the post 100 can be rotated one or more times to wind the barrier 137 around the post 100. This is considered to be advantageous as is the tension being relatively evenly distributed along a substantial portion of the full height of the barrier.

Figure 8 illustrates the general tensioning post arrangement 32 that is located midway between the barrier 35 and the barrier 37. The general tensioning post arrangement 32 comprises a first portion 172 for extending into the ground; and a second portion 174 for engaging the barrier 35 above the ground. The post arrangement 32 includes a tensioning mechanism 176 for moving the second portion 174 between a first position and a second position to tension the barrier 35. The tensioning mechanism 176 operates in a similar manner to the tensioning mechanism 128 described in relation to Figure 7. The tensioning mechanism 176 is adapted to rotate the second portion 174 about a longitudinal axis 178 of the post arrangement 32.

The post arrangement 32 includes a third portion 180 for engaging the second barrier 37. The third portion 180 is similar to the securing portion 42 described in relation to Figure 4. The post arrangement 32 allows two barriers to be connected together and for the post 32 to be used to tension one of the barriers. In this arrangement a handle (not shown) is used to tension the barrier 35. As the second portion 174 engages a hole in a base member 182 this causes the third portion 180 to rotate in a similar direction. In another embodiment the position of the third portion 180 is independent of the position of the second portion 174. Nonetheless, in this arrangement the position of the second portion 174 and the third portion 180 are dependent on one another.

In the embodiment, the post arrangement 32 includes a post 182 having a flange 184 with a locking hole 186 for the second portion 174 and an ordinary hole 188 for the third portion 180. A base 190 forming part of the post 32 is provided to prevent rotational movement. Referring to Figure 9 there is shown a method 200 according to a further preferred embodiment of the present invention. The method 200 advantageously provides a method for erecting safety barrier system 201 for preventing workers falling off the edge 202 of a bench 204 in an open cut mine. The method 200, at block 206, comprises providing a safety line 208. This involves surveying the bench area and marking holes 210 about 5m from the edge 202 of the bench 204. In the embodiment the holes 210 are drilled about 30 to 35m apart, based on the length of the edge 202.

Following this, collars 212 are inserted into the holes 210. Poles 214 are then fed through the collars 212 allowing for the safety line 208 to be attached and tensioned therebetween. Workers can then attach themselves to the safety line using standard inertia cable harness systems for arresting falls such as harness system 216 shown attached to a worker 217. Barnacle(tm) harness systems 216 have 5 metres of travel with a self retracting inertia lock are presently preferred. Following this a maximum of about two or more people (to the load standard of the safety line) can install the safety barrier system 201 as illustrated in Figure 9. To install the safety system, pole positions are pre-determined and hole locations 222 and 224 locations surveyed. At block 220 the method 200 includes drilling a number of spaced apart fence post holes 222 into the ground at the hole locations to a predetermined design length. At the same time a number of rotational locking holes 224 are drilled next to holes 222 for tensioning purposes. A base 226 and a post 225 are positioned next to each of the holes 222. Similarly, rotational locking base 228 is positioned next to each of the holes 224. Each of the bases 226, 228 is inserted into the respective holes 222, 224 following which the poles 225 are inserted into the bases 226. Connection elements similar to connection element 170 (shown in Figure 7) are then positioned to extend from the bases 228 (in the holes 224) to a respective adjacent base 226 (in the holes 222) so as to lock two bases 226 for tensioning purposes.

Following this, at block 230, two 15m barriers 232 are connected to securing portions (not shown) of the posts 225 so that the barriers 232 extend therebetween. The barriers 228 are subsequently tensioned by moving and fixing at least one of the securing portions relative to the ground. Advantageously the steps can be repeated to provide a safety system having as many barriers 232 as required. This is considered to be particularly advantageous as edges much longer than edge 202 can be accommodated.

After the safety barrier system 201 is installed, the safety line 208, collars 212 and posts 214 are removed. With the safety barrier system 201 extending across the length of the bench 204 workers are able to operate in an environment where they are relatively unlikely to fall over the edge 202. The method 202 provides an advantageous modular system.

The advantages are considered to be significant in that there is provided a real safety barrier and not just face delineation. The safety system 218 is relatively easy and fast to set up and its modular nature means that that barriers can be linked together to protect an edge of virtually any length. No guy ropes, tethers or tensioning cables are required. The system is also able to accommodate edges having bends and corners. The barriers are flexible and having desirable elastic properties being made from polyester material. This removes issues associated with rigidity and difficulties in construction. Further advantages include the tensioning mechanism allowing for variation in the location of holes together with barriers of different size.

In addition, the safety barrier can be readily dissembled and reused which provides further advantages. It is a simple matter of releasing the tension in the barriers 232, removing the barriers 232, removing the posts 225, removing the locking bases 228 and then removing the bases 226.

In summary it is considered that there has been provided an advantageous system in terms of its use, construction, disassembly and the safety provided when working on the benches of open cut mines.

An example of such a safety system 310 is shown in Figure 10. As before, the safety system 310 is advantageously provided for preventing workers falling over an edge 312 of a bench in an open cut mine. The safety system 310 includes plurality of post arrangements 314 each having a first portion 316 for being secured in the ground and a second portion 318 for extending above the ground. There is provided a first barrier 320 and a second barrier 322 extending between the post arrangements 16. Two of the post arrangements 16 consist of a tensioning post arrangement 324 each having a tensioning mechanism. The tensioning mechanisms are adapted to move a second portion of the tensioning post arrangements from a first position to a second position, relative to the ground, to respectively place the first barrier 320 and the second barrier 322 in tension along a substantial portion of the full height of the barriers.

In this particular embodiment the barriers 320, 322 can support 500kg of force. Posts arrangements and barriers of differing heights are able to be used in different systems depending on the requirements. In this embodiment the barrier 320 and the barrier 322 are 1.4m in height and are highly visible. All aspects of the system have been designed for safety and are preferably intrinsically safe as required for use in industries that involve the use of explosives.

Referring to Figure 1 1 there is shown a further post arrangement 400 according to a further preferred embodiment of the present invention. Advantageously the post arrangement 400 advantageously allows an operator to tension a barrier by turning a handle 401 and then for the operator to release the handle 401 with the post arrangement 400 automatically preventing movement in a reverse direction which would release the tension applied to the barrier.

The post arrangement 400 includes a post 402 and a base 404. The post 402 includes a first portion 406, a second portion 408 and flange 410 therebetween. The flange 410 has a ratchet 41 1 in the form of a gear wheel 412 on its underside. The base 404 includes a locking member 414 and a ratchet lock in the form of a pawl 416. The pawl 416 is adapted to engage the gear wheel 412 and prevent reverse movement of the post 402 when in position on the base 404. Figure 12 shows a further post system 500 that prevents movement in a reverse direction. In the post system 500 there is provided a post 502 and a securing portion 504 for holding a barrier 506. The securing portion 504 is fixed to the post 420 using a number of padlocks. In order to prevent the ratchet pawl from being depressed to release tension, a padlock 508 is provided to hold the pawl with the body of the pawl extending through the arm of padlock. In operation the post 502 is rotated in clockwise direction using a top handle to tension the barrier 506. This causes the barrier 506 to wrap around the post 502. When the barrier 506 is correctly tensioned, the padlock 508 is applied to lock the pawl in place. In this embodiment, the securing portion 504 is advantageously permanently secured to the barrier 506. This is considered to advantageously assist with rolling the barrier/net up for transport and storage.

Figure 13 illustrates a further preferred embodiment of the present invention in the form of a post arrangement 600. The post arrangement 600 includes a first portion 602 for extending into the ground and a second portion 604 for engaging a barrier 605 above the ground. The post arrangement 600 further includes a tensioning mechanism 606 for moving the second portion 604 of the post arrangement 600 between a first position and a second position to tension the barrier 605. The post arrangement 600 provides an advantageous locking mechanism as will be described. As shown in Figures 13 and 14, the post arrangement 600 includes a base portion 608. The base portion 608 includes an upper portion 610 and a lower portion 612 defining a cavity 614 therebetween. A cylindrical member 616, for engaging a predrilled hole, extends downwardly from the lower portion 612. The upper portion 610 and the lower portion 612 are advantageously connected by an extension of the cylindrical member 616 extending upwardly from the lower portion 612. The member 616 provides a cylindrical passage 618 for receiving the first portion 602 of the post arrangement 600.

A post securing element 620 in the form of a plate is provided between the first portion 602 and the second portion 604 of the post arrangement 600. The post securing element 620 includes a number of recesses 622 around its circumference in the radial plane of the securing element 620. A corresponding locking hole 624 is provided adjacent each of the recesses 622. In the present embodiment there are advantageously about ten recesses 622 with ten corresponding locking holes 624. As a result each tensioning step is associated with a 36 degree rotation angle. A base securing element 626 in the form of a pivoting member having a base 630 and an upstanding element 632 is provided to cooperate with the post securing element 620 to advantageously provide a locking arrangement 634. The locking arrangement 634 is provided as a pin slot type locking arrangement for preventing removal of the first portion 602 of the post arrangement 600 from the base portion 608.

Again referring to Figure 14, the upper portion 610 includes a hole 638 which together with a hole 640 in the base securing element 626 provides a pivot 642. Using the pivot 642 it is possible to bring the upstanding element 632 of the base securing element 626 into engagement with one of the recess 622 of the post securing element 620. Basically the base securing element 626 pivots within the cavity 614 between the upper and lower plates 610, 612 with the upstanding element 632 moving further into and out of a recess 644 in the upper plate 610. In this embodiment the recess 644 is provided as a open slot of a similar configuration to the recesses 622 of the post securing arrangement 620.

In this embodiment the upstanding element 632 includes a locking plate 646 that extends from its upper end of the pin to provide a means by which the upstanding element 632 can be locked within the recess 644 and within one of the recesses 622 of the post securing element 620. This is achieved by virtue of the locking plate having a locking hole 648 that is sized and positioned to lie over one of the locking holes 624 of the securing element 620.

With the base 630 of the base securing element 626 fixed within the cavity 614, a pad lock 645 can advantageously be placed through the corresponding locking hole 624 of the post securing element 620, through the locking hole 648 of the locking plate 646 and then through a locking hole 650 provided in the upper portion 610. Such an advantageous locking system serves to advantageously prevent removal of the first portion 602 of the post arrangement 600 from the base portion 608. If the first portion 602 were pulled upwardly, the post securing arrangement 620 would bear against the underside of the locking plate 646 with upward motion being resisted by the base 630 of the base securing element 626 bearing against the underside of the upper plate 610. To remove the first portion 602 from the base portion 608 the padlock 645 must first be removed and the upstanding member 632 moved out of the recess 644 by pushing on a side 654 of the base securing element 626. As shown in Figure 14, the base securing element 626 includes a first side 656 and the second side 654. The sides 654, 656 are configured to limit movement of the base securing element 626 to movement between a first position and a second position. As shown in Figure 13, the sides 654, 656 are adapted to bear against each side of a corner portion of the upper plate 610 as shown in Figures 13 and 14.

With the locking arranging 634 now having been described, it will be appreciated that the locking arrangement 634 provides a pin and brake type mechanism instead of having a single pinned connection as shown in the embodiment of

Figure 1. This is considered to be advantageous. Both the pin and brake are used to keep the tension on the barrier/net and to keep the base plate and pole in position. In the embodiment there is only a single tension slot 644 in the upper plate 610 for the brake mechanism to rotate in and a single hole for the brake net pin.

Further features of the post arrangement 600 include the provision of bushes along the longitudinal offset element 658 that engage the barrier 605. As shown in Figure 14, there is provided a first bush 662 and a second bush 664. It is considered that both bushes 662, 664 hold up the straps of the barrier 660 and that without the bushes the barrier would sag and more tension would be required to keep the net parallel to ground level. For this reason the provision of the bushes 662, 664 is considered to be advantageous.

Additional features include a hole 666 in the upper plate 610 provided for an additional pole attachment where the pole extends through one of the recesses 622 in the post securing element 620 in the hole 666.

As would be apparent from the Figures 13 and 14, tie rod holes 667 that connect to the base portion 608 to a securing base portion 668 are offset from centre. The tie rods in the present embodiment fix between vertical tabs 670 rather than through the centre of the base plate pipes. As shown in Figure 15, the second portion 604 includes a tightening hole 676 adapted to receive a steel bar. The tightening hole advantageously doubles as a locking hole 678. With the locking arrangement 634, the barrier is tensioned using the tightening hole 676, the tightening bar is removed and a locking pin 680 is extended through the tightening hole 676. The locking pin 680 is then locked in position using a padlock 683 as shown.

In addition, to prevent the base portion 608 being removed, a hole is provided in each end of the fixing bars 682 for a padlock 684 . This is also considered to be advantageous. Figure 16 shows an idler pole 700 according to a further embodiment. The idler pole 700 has a swivel 702 located at the top. The swivel includes a hook element 704 that is designed to hold the top net strap up and parallel to the ground. As the net is tensioned the hook element 674 is advantageously able to rotate around the centre line of the pole to compensate for the final net position. The hook element 704 advantageously fits into the top pipe and can rotate around an axis of pipe, to allow for net movement during tensioning.

It is to be recognised that embodiments of the present invention may also find application in other areas. These areas may include rail duplications, plant expansions, road works, pit extensions, lookouts, and safety applications in general.

As would be apparent, various alterations and equivalent forms may be provided without departing from the spirit and scope of the present invention. This includes modifications within the scope of the appended claims along with all modifications, alternative constructions and equivalents. In the present specification, the presence of particular features does not preclude the existence of further features. The words "comprising", "including" and "having" are to be construed in an inclusive rather than an exclusive sense.