AU2011223492B2

AU2011223492B2 - A system and method for charging a blast hole

Info

Publication number: AU2011223492B2
Application number: AU2011223492A
Authority: AU
Inventors: David Cooper; Simon Kitson
Original assignee: GRANGE RESOURCES Ltd
Current assignee: GRANGE RESOURCES Ltd
Priority date: 2010-03-01
Filing date: 2011-03-01
Publication date: 2014-05-29
Anticipated expiration: 2031-03-01
Also published as: WO2011106830A1; AU2011223492A1

Abstract

The present invention relates to the system and method for charging a flowable explosive material into a blast hole via a hose. The hose is wound on a reel of hose reel assembly which is mounted to a vehicle and a boom extending from the vehicle has a hose drive assembly for advancing the hose from an outer end of the boom. The hose is retrieved on the reel by operation of the first motor of the hose reel assembly, and the hose is paid out from the end of the boom by operation of a second motor of the hose drive assembly to advance the hose down a blast hole.

Description

PCT/AU2011/000227 Received 14/12/2011 A system and method for charging a blast hole Field of the invention 5 The present invention relates to a system and method for charging a blast hole with an explosive material. Background of the invention 10 To facilitate extraction of an ore body from an open pit mine, it is known to drill blast holes into the ore body and load the blast holes with an explosive charge. Detonation of the charge breaks the rock into loose material that mining equipment can dig and carry. In certain situations, there is a significant risk of rock falls from slopes above a blast 15 site. Where the pathway of the rock fall includes the blast site, the consequences of a rock fall event can include personal injury and equipment damage. There is a need to mitigate the risks associated with rock fall events. 20 Summary of the invention The present invention provides a system that charges a blast hole, the system being mountable on a support vehicle that has a body and a boom with an inner end that is movably connected to the body, the system including a charge delivery module that 25 includes: a hose in which a flowable explosive material is conveyed; a hose reel assembly to be attached to the support vehicle, the hose reel assembly having a reel onto which the hose can be wound, and a first motor to rotate the reel; and a hose drive assembly to be mounted on the outer end of the boom that provides 30 downward delivery of the hose and the flowable explosive material into a downwardly oriented blast hole, the hose drive assembly having at least one drive wheel that is driven by a second motor and is arranged to grip the hose, wherein the second motor is arranged to drive the drive wheel to pay out hose from the reel and advance the hose downwardly into a blast hole; the first motor is arranged to 35 rotate the reel to retrieve hose onto the reel and in response to relative movement supply vehicle either one or a combination of the first and second motors are operated so as to pay out hose from the real or retrieve onto the reel. AXXPT-iT)fl 4Z-TPFT WO 2011/106830 PCT/AU2011/000227 -2 Throughout this specification the terms "flowable explosive materials" and "liquid explosive material" have been used interchangeably and embrace any explosive material that can be conveyed within a hose. 5 In certain embodiments, the first motor may be operated with the second motor to control movement of hose on/off the reel. When the second motor and drive wheels are operated to pay out hose, the first motor can be operated to control the speed of hose leaving the reel. In this mode of 10 operation, the first motor may be operated to provide a controlled amount of resistance to the reel. Suitably the length of the boom is adjustable, and the first and/or second motors are operated so as to pay out or retrieve hose from the reel as the boom is extended or 15 retracted. More suitably, a controller control operation of either one or a combination of: i) an actuator that extends or retracts the boom; or ii) the first and/or second motors so as to pay out or retrieve hose so that the hose is maintained in a linear arrangement along the length of the boom. Even more suitably, the length of the boom is adjusted by an actuator and the controller controls operation of the first and/or second motors so as to pay out or 20 retrieve hose based on changes in length of the boom. The actuator that adjusts the length of the boom may adjust the length of the boom at a fixed speed or at a variable speed. In an embodiment, the first motor is operable to retrieve the hose from the blast hole onto the reel at a rate so that a free end of the hose is maintained above the level of the 25 explosive material that is discharged into the blast hole. Suitably, the first motor is operable to wind the hose onto the reel at a rate that equals or is greater than the rate at which the level of explosive materials increases in the blast hole. An advantage of this feature is the explosive material can be freely discharged from the hose without a backup of explosive material in the hose or without the hose becoming submerged in the explosive material. 30 In some embodiments, the rotational speed of the reel can be proportional to the effective diameter of reeled hose, so that hose speed is constant. In some embodiments, the reel is constructed to provide flat-winding of the hose. 35 Suitably, the hose is wound in a spiral formation in a single layer in which the hose is progressively wound on itself.

WO 2011/106830 PCT/AU2011/000227 -3 The hose reel assembly may further comprise a drip tray beneath the reel. The hose reel assembly may also include an inlet pipe with one end connected to the hose and a connector at the opposite of the pipe for connection to a feed line of explosion 5 material. The feed line may be any feed source of the explosive material, and typically is a hose or pipe extending from a supply pump and storage tank carried by an auxiliary support vehicle. The inlet pipe can include a first pivot coupling on the reel axis. Alternatively or 10 additionally, the inlet pipe can include a second pivot coupling that allows variations in relative angles between the boom and the feed line. The hose drive assembly can have a frame that facilitates mounting the assembly onto the boom. 15 In certain embodiments, the hose drive assembly has two counter-rotating drive wheels. The second motor can be a hydraulic motor that operates both drive wheels. The hose drive assembly can have a guide wheel to allow the hose to freely turn on 20 the end of the boom. The guide wheel preferably has a radius that is at least that of the minimum bending radius of the hose. The hose drive assembly may further comprise a detonator tube into which a detonator can be loaded for transport to the blast hole. The detonator tube can further 25 include a platform that can be pivoted between a support position and a release position. The hose drive assembly may further comprise one or more string tubes through which a string attached to the detonator can be passed. 30 In some embodiments, two string tubes are provided, and the hose drive assembly further comprises a cutter for cutting the string between the string tubes. In some embodiments, a camera may be provided on the hose drive assembly to enable provision of visual information of the blast hole and certain parts of the hose drive 35 assembly to an operator.

PCT/AU2011/000227 Received 14/12/2011 For systems to be used on support vehicles that include a rotatable turret, the second pivot coupling can be provided on the rotational axis of the turret. The charge delivery module may further comprise one or more hose carriers 5 attached to the boom for restraining the hose. The, or each, carrier can include a pair of rollers between which the hose can be retained. The system for charging a blast hole can further comprise a stemming module that is mountable to the outer end of the boom, the stemming module including a bin for holding 10 stemming material, an actuator, and a gate operated by the actuator to selectively release stemming material. The bin can have capacity to hold sufficient stemming material to stem approximately four blast holes. 15 In some embodiments, the bin narrows towards the gate to form a chute. The system for charging a blast hole can further comprise a marking module that is mountable to the outer end of the boom, the marking module including a magazine for 20 holding marking blocks, an actuator, and a gate operated by the actuator for releasing marking blocks individually. The magazine can have capacity to hold twenty marking blocks. 25 The present invention also relates to a method of charging a downwardly oriented blast hole using a charge delivery module having a hose, a hose reel assembly attached to a vehicle and having a reel on which the hose can be wound, and a hose drive assembly attached to an outer end of a boom extending from the vehicle, the method including: paying-out the hose from the hose reel assembly and into the blast hole by operation 30 of the hose drive assembly; conveying flowable explosive material within the hose to discharge the explosive material into the blast hole; withdrawing the hose from the blast hole by operation of the hose reel assembly to retrieve the hose onto the reel; and 35 moving the outer end of the boom toward and away from the vehicle and in response to the movement of the outer end of the boom operating either one or a combination of the first and second motors so as to pay out hose from the reel or retrieve hose onto the reel. A ?iAPMT'~1T QT-IPT WO 2011/106830 PCT/AU2011/000227 -5 Once the desired volume of liquid explosive material has been passed into the blast hole, the first motor can be operated to reel in hose and withdraw hose from blast hole. In an embodiment the method includes controlling the rate at which the hose is 5 withdrawn from the blast hole as a function of: * the diameter of the blast hole, * the depth of the blast hole, " the volumetric flow rate of the explosive material within the hose. 10 The method can further include lowering a free end of the hose to the base of the blast hole to measure the depth thereof prior to conveying the explosive material within the hose and discharging into the blast hole. Suitably, the charge delivery module includes a rotary encoder associated with a 15 rotating wheel over which the hose travels and a controller, and controlling the rate at which the hose is withdrawn from the blast hole includes using an output of the encoder as feedback to the controller. The step of withdrawing the hose from the blast hole may include rotatably driving 20 the reel to wind up the hose by operation of a first motor. Suitably, the first motor is operatable to retrieve the hose from the blast hole and reel the hose onto the reel at a rate so as to keep a free end of the hose above the level of the explosive material while the material is discharged into the hole. 25 The step of paying out the hose may include unwinding the hose from the reel and advancing the hose downwardly into the blast hole by operation of a second motor that advances the hose from an outer end of the boom. In an embodiment, the length of the boom is adjustable, and the controller operates 30 the first and/or second motors so as to payout or retrieve hose from the reel in response to the boom being extended or retracted. In certain embodiments in which the hose drive assembly includes a detonator tube, and a platform within the detonator tube that is pivotable between a support position and a 35 release position, the method can further involve: * positioning the platform in the support position; WO 2011/106830 PCT/AU2011/000227 -6 * placing a detonator on the platform; and " once the detonator tube is located over the blast hole, pivoting the platform to the release position to release the detonator. 5 Charging the blast hole can further involve: * providing a stemming module as previously described, and mounting the stemming module on the outer end of boom; * filling the bin with stemming material; * locating the gate above the blast hole; and 10 e operating the actuator to open gate to release stemming material into the blast hole. The present invention relates to a method for charging a blast hole, the method comprising: 15 providing a support vehicle having a body and a boom with an inner end that is connected to the body; providing a system for charging a blast hole that includes a charge delivery module as previously described, attaching the hose reel assembly to the support vehicle adjacent the inner end of the boom, and mounting the hose drive assembly on the outer end of the 20 boom; connecting the connector to a liquid explosive feed line; locating the hose drive assembly over the blast hole; operating the second motor to reel out hose and push the hose downwardly into the blast hole; 25 passing liquid explosive material from the liquid explosive feed line through the hose and into the blast hole. Brief description of the drawings In order that the present invention may be more easily understood, an embodiment 30 will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1: is a side elevation view of charge delivery module of a system for charging a blast hole according to an embodiment of the invention, the system being mounted on a support vehicle; 35 Figure 2: is a top view of the charge delivery module and support vehicle of Figure 1; WO 2011/106830 PCT/AU2011/000227 -7 Figure 3: is an enlarged view of a hose carriers and snubber wheel of the charge delivery module of Figure 1; Figure 4: is a side view of the main hose reel assembly of the charge delivery module of Figure 1; 5 Figure 5: is a side elevation view of the hose drive assembly of the charge delivery module of Figure 1; Figure 6: is a front elevation view of the hose drive assembly of Figure 5; Figure 7: is a section view of the hose drive assembly, as viewed along the line A-A in Figure 5; 10 Figure 8: is a section view of the hose drive assembly, as viewed along the line B-B in Figure 5; Figure 9: is a side elevation view of a detonator tube of the hose drive assembly of Figure 5; Figure 10: is a schematic plan view of a blast hole pattern, showing the 15 delivery module and support vehicle of Figure 1; Figure 11: is a front perspective view of a stemming module of the system for charging a blast hole according to an embodiment of invention; Figure 12: is a rear perspective view of a stemming module of Figure 11; Figure 13: is a first perspective view of a marking module of the system for 20 charging a blast hole according to an embodiment of invention; Figure 14: is a second perspective view of a marking module of Figure 13; and Figure 15 : is a block diagram of the system and method for charging flowable explosive material into the blast hole. 25 Detailed description of the preferred embodiment Figures 1 and 2 show a charge delivery module 100 of a system for charging a blast hole according to an embodiment of the present invention. The charge delivery module 100 is mounted on a support vehicle 10. The support vehicle 10 has a body 12, and a boom 14 30 with an inner end that is rotatably mounted on the body 12 to rotate about an upright axis. The charge delivery module 100 includes a hose 102 in which a flowable or liquid explosive material is conveyed during charging of a blast hole. The module 100 also has a hose reel assembly 104, and a hose drive assembly 106. 35 WO 2011/106830 PCT/AU2011/000227 -8 The hose reel assembly 104 is to be attached to the support vehicle 10 adjacent the inner end of the boom 14. In this particular embodiment, the hose reel assembly 104 is attached on the boom 14 itself. The hose reel assembly 104 includes a reel 108 onto which the hose 102 can be wound, and an inlet pipe 110 to which one end of the hose 102 is 5 connected. The opposing end of the pipe 110 has a connector 112 for connection to a liquid explosive feed line 20. Additionally, the hose reel assembly 104 includes a first motor 114, which is arranged to rotate the reel 108 to reel in hose 102. The hose reel assembly 104 will be described in further detail below. 10 The hose drive assembly 106 is to be mounted on the outer end of the boom 14 for downward delivery of liquid explosive into a blast hole. Detail of the hose drive assembly 106 is shown in Figures 5 to 9. The hose drive assembly 106 includes drive wheels 116 that are driven by a second motor 118. In use, the hose 102 is gripped between the drive wheels 116, and the wheels 116 driven by the second motor 118 to pay out hose 102 from the reel 15 108, and thus push the hose 102 downwardly into a blast hole or allow the hose 102 to advance downwardly under gravity. The hose drive assembly 106 includes a frame 119 that facilitates mounting the hose drive assembly 106 on the end of the boom 114. The drive wheels 116 and second motor 20 118 are mounted on the frame 119. In this particular embodiment, the drive assembly 106 has two counter-rotating drive wheels 116, one to each side of the hose. The drive wheels 116 are both driven (in opposing directions) by the second motor 118 simultaneously to move the hose 102. In 25 some alternative embodiments, the drive assembly may have a single drive wheel that co operates with a free wheel to move the hose through the gap between the drive and free wheels. Some support vehicles 10 include a hydraulic system. When the charge delivery 30 module 100 is to be used on these support vehicles, the first and/or second motors 114, 118 can be hydraulic motors that are connected to the vehicle's hydraulic system. It is possible that the first and/or second motors 114, 118 may also be driven by any other power source which may, for example, include electric motors, pneumatic motors, combustion driven motors and so forth. 35 WO 2011/106830 PCT/AU2011/000227 -9 As can be seen from Figure 1, the hose 102 turns through 900 at the end of the boom 14. To guide the hose 102 around the turn, and to avoid kinking the hose, the drive assembly 106 includes a snubber wheel 120 and a final guide wheel 122. The snubber wheel 120 is mounted on a pivotable support arm 124 that forms part of the frame 119. A 5 turnbuckle 125 restrains the support arm 124 and allows adjustment to a desired inclination. The final guide wheel 122 is supported on the frame 119. A roller 126 is also mounted on the support arm 124. The snubber wheel 120, roller 126 and support arm 124 define a throughway through which the hose 102 can pass, and together prevent the hose 102 from dislodging from the snubber wheel 120. 10 As shown in Figure 15, suitably operation of the first and/or second motors for payout or retrieval of the hose is controlled by a controller 171 as a function of: * the diameter of the blast hole, " the depth of the blast hole, 15 0 the volumetric feed rate of the explosive material within the hose 102. It will be appreciated that as the diameter of the reel 108 increases, i.e., as the hose 102 is wound on the reel 108, the rate at which the reel 108 rotates will be reduced by the first motor 114 in order to retrieve the hose at a constant rate. 20 The volumetric flow rate of the flowable explosive material within the hose may be fixed or variable, for example, a variable flow rate may be provided by a variable speed pump or a flow regulator that may or may not form part of the charge delivery module. 25 The final guide wheel 122 can be provided with a rotary encoder 170 to determine rotation of the wheel 122 as hose 102 is paid out and reeled in. This provides an accurate measure of hose movement since the final guide wheel 122 freewheels with movement of the hose 102. It will be appreciated that the rotary encoder 170 may be associated with any one of the rollers or wheels on which the hose passes including: guide wheels 122, drive 30 wheels 116, snubber wheel 120, rollers 162 and 164, and guide wheel 150. The rotary encoder may be used to calculate the rate of payout and retrieval of the hose 102. An output of the rotary encoder may then be received by the controller (see Figure 15) for that controls operation of the first and/or second motors to payout or retrieve hose 35 based on output of the rotary encoder.

WO 2011/106830 PCT/AU2011/000227 -10 On account that the hose is flexible and may to an extent collapse when wound onto the reel, or stretch or contract longitudinally, the controller 171 may, in addition to the hole diameter, and volumetric flow rate, control operation of the first and/or second motors may also be based an output of the encoder 170. 5 Suitably, operation of the first and/or second motors 114, 118 is controlled to ensure that the hose 102 is maintained above the level of the explosive material within the blast hole. 10 It will be appreciated that the controller 171 may be implemented by a computer known in the art. Alternatively, the controller 171 may be operator personnel who manually operate the speed of the first and/or second motors 114, 118. The hose drive assembly 106 includes a detonator tube 128, which is shown most 15 clearly in Figure 5 and 9; for clarity, the detonator tube 128 is omitted from Figure 6. In use, the detonator tube 128 holds a detonator and booster (which are also known as an initiating device) for carrying to the blast hole, and subsequent deployment into the blast hole. For convenience, the detonator and booster will herein be referred to collectively as a "detonator". The detonator tube 128 has a slit 130 that extends lengthwise along the entire 20 length of the tube 128. The slit 130 includes a narrow broad opening 132 spaced from the bottom end of the tube. The opening 132 is sized to allow a detonator to pass through the side wall of the tube 128. A detonator platform 134 is provided within the detonator tube 128. The detonator 25 platform 134 is illustrated in Figure 9. The platform 134 is arranged to pivot on a pin 136, between a support position P 1 - in which the platform extends transversely across the tube 128 to block passage of the detonator down the tube - and a release position P 2 . In Figure 9, the support position of the platform 134 is shown in light lines, and the release position is shown in dark lines. When the platform 134 is in the release position, the detonator can 30 pass downwardly through the tube for delivery into the blast hole. A mechanism 138 is provided that moves the platform 134 between the support and release positions. The mechanism 138 includes an actuator to enable pivoting of the platform 134 on the pin 136. 35 WO 2011/106830 PCT/AU2011/000227 - 11 Prior to charging of the blast hole, a string is attached to the detonator. During charging, a handler works the string to position the detonator vertically within the blast hole; typically approximately 1 metre above the base of the hole. A pair of string guide tubes 140a, 140b and an eyelet 142 are provided. The string can be passed through the guide 5 tubes 140a, 140b and the eyelet to enable the string to move easily through the detonator tube 128. In practice, the handler will be in a range of different positions, which result in a range of different angles relative to the boom. The string tubes 140a, 140b and eyelet 142 accommodate these different positions. 10 The string is passed through the slit 130 and through the string guide tubes 140a, 140b when the detonator is placed on the platform 134. The string can be operated by the support vehicle operator to position the detonator within the blast hole. However, in practice it is likely that other personnel would work the string to minimize the number of tasks required to be performed by the support vehicle operator. 15 A small gap is provided between the string tubes 140a, 140b. A cutter 144 is provided to cut the string in the gap. In use, once the blast hole has been charged with liquid explosive material the string attached to the detonator is cut by the cutter, which enables the hose drive assembly 106 to be moved away from the blast hole without 20 disturbing the detonator/charge. The cutter 144 may be in the form of a blade operated by a solenoid. As illustrated in Figures 5 and 7, the frame 119 has mounts 145a, 145b that co operate with like mounting points on the boom 14 of the support vehicle 10 to mount the 25 hose drive assembly 106 on the end of the boom 14. A camera (not illustrated) may be provided on the hose drive assembly 106 that, together with a display provided to the operator of the support vehicle 10, enables the operator to quickly and accurately align the hose drive assembly 106 over a blast hole. 30 The hose reel assembly 104 is illustrated in further detail in Figures 2 and 4. As shown in these Figures, the reel 108 is constructed to provide flat winding of the hose to form a flat spiral. In some embodiments the hose 102 can be approximately 60 metres in length. Flat winding of the hose facilitates packaging of the hose on a support vehicle. 35 Alternatively, it will be appreciated that the reel 108 may also be in the form barrel in which the hose 102 may be spread over the circumferential wall of the barrel.

WO 2011/106830 PCT/AU2011/000227 -12 The reel 104 includes upper and lower reel frames 146a, 146b between which reeled hose is contained. Beneath the lower reel frame 146b, a drip tray 148 is provided to catch any liquid explosive material that drops from the reeled hose 102. 5 As previously described, when the first motor 114 is operated to reel in hose 102, the second motor 118 (and thus also the drive wheels 116) are allowed to freewheel. In this embodiment, when the second motor 118 and drive wheels 116 are operated to pay out hose 102, the first motor is also operated to control the speed of hose 102 leaving the reel 10 108. To this end, the first motor 114 may be operated to provide a controlled amount of resistance to prevent over running of hose 102 off the reel 108. As will be appreciated, the effective diameter of the reeled hose 102 changes with length of hose on the reel 108. During reeling in/paying out hose 102, the first motor 114 is 15 controlled to ensure the rotational speed of the reel 108 is proportional to the effective diameter. In this way, a constant speed of reeling in/paying out of hose 102 can be achieved. The hose reel assembly 104 further includes an initial guide wheel 150 that guides 20 hose 102 from the boom 14 onto and off the reel 108. As shown in Figures 1 and 5, the inlet pipe 110 includes a first pivot coupling 152 on the rotational axis of the reel 108. This pivot coupling 152 allows the reel 108 to rotate without winding up the inlet pipe 110. The inlet pipe 110 further includes a second pivot 25 coupling 154 that allows for variations in relative positions (and thus angles) between the boom 14 and the feed line 20. The feed line 20 extends from a reserve of explosive materials, such as a backup vehicle (not illustrated in the Figure) having a storage vessel and pumps for pumping the explosive material along the feed line 20 which is connected to the inlet pipe 110. 30 The body 12 of the support vehicle 10 illustrated in the Figures has a base and a turret that can rotate on the base. The turret includes the operator's cabin and the boom 14. Providing the second pivot coupling 154 on the rotational (slewing) axis R of the turret allows the boom 14 to be rotated without disruption to the feed line 20. 35 WO 2011/106830 PCT/AU2011/000227 -13 The hose reel assembly 104 includes a support 156 that supports the inlet pipe 110 on the boom 14. As shown in Figure 1, the support 156 can be provided between the hose reel 108 and the second pivot coupling 154. 5 The hose reel assembly 104 is provided with limit switches that stop the charge delivery module 100 from operating in the event of loss of control of the first and/or second motors 114, 118 which may result in over-winding the hose 102. The charge delivery module 100 includes hose carriers 158 attached to the boom 14. 10 The carriers 158 minimize movement of the hose 102 between the hose reel assembly 104 and hose drive assembly 106 due to any slack in the hose 102. Each hose carrier 158 has a mounting bracket 160 to which two rollers 162, 164 are mounted. The rollers 162, 164 are on opposing sides of the hose 102 to restrain or guide the hose 102 in a direction along the boom 14. Suitably, the rollers 162, 164 have an outer circumferential wall with a concave 15 profile for receiving the hose 102. As can be seen in Figures 1 and 3, the mounting brackets 160 are located at the ends sub-sections of the boom 14. Ideally the boom 14 is extendible and retractable to increase the reach of the boom depending on the relative position of the blast holes to the vehicle 10. The length of the boom 14 is adjustable via any suitable actuator 173, such as hydraulic, or a gear meshing with teeth. Ideally, the controller 171 can 20 operate the first and/or second motors 114, 118 to payout or retrieve hose 102 from the reel 108 to allow for changes in length of the boom 14 and maintain the hose 102 in a linear arrangement along the length of the boom 14. In embodiments in which the charge delivery module 100 is to be used on a support 25 vehicle with a telescopic boom, when the boom 14 is retracted or extended the reel 108 is rotated by the first motor 114 to reel in or pay out hose 102, as required and proportionally to the speed of boom retraction/extension. In some applications, a slewing telehandler is a particularly suitable support vehicle. 30 For example, the slewing telehandlers sold by the Merlo Company under the trade name Roto can be used. A slewing telehandler has a slewing turret on which the operator's cabin and the boom are mounted. In addition, the boom is telescopic, in some cases to a maximum length of approximately 16 metres.

WO 2011/106830 PCT/AU2011/000227 -14 Figure 10 shows schematically in plan view a typical blast site B beside a sloped wall W within an open pit mine. As will be appreciated, risk of injury/damage decreases with distance from the base of the wall W. 5 In Figure 10, the location of blast holes are indicated by dark circles. The slewing telehandler can be driven to a location nearby, but spaced from, the wall W beside the blast site. From this location, using the system for charging a blast hole, charging work can be carried out on any blast hole within the maximum operating radius of the boom. In particular, this has the advantage that the support vehicle operator does not need to be any 10 closer than the maximum boom length from the base of the wall W. Broken line X indicates the minimum distance the support vehicle must approach the base of the wall W. Further, broken line Y in Figure 10 indicates the minimum distance that any other personnel (such as the handler working on the string/lead for the detonator, and operators of 15 the liquid explosive material supply vehicle U) need approach the base of the wall W. Broken line Y indicates a distance of twice the maximum boom radius from the base of the wall W. Typically, physical barricades and/or signs Z will be erected to keep unauthorized 20 personnel out of the operating area that includes blast site. Figures 11 and 12 show a stemming module 200 of a system for charging a blast hole according to an embodiment of the present invention. The stemming module 200 is to be mounted on a support vehicle 10. In particular, the stemming module 200 can be 25 mounted on the outer end of the boom 14 of the support vehicle 10. The stemming module 200 includes a bin 202 for holding stemming material, and an actuator 204 and gate 206 at the base of the bin 202 for releasing stemming material. In use, the stemming module 200 can be held above a blast hole that has been charged, and 30 the actuator operated to open and close the gate to release stemming material into the blast hole. In the stemming module illustrated in Figures 11 and 12, the bin 202 has capacity to stem approximately four blast holes. 35 WO 2011/106830 PCT/AU2011/000227 -15 The bin 202 is shaped to narrow towards the gate 206 to form a chute 208 for narrow discharge of stemming material. The stemming module 200 has mounts 210a, 210b that co-operate with like 5 mounting points on the boom 14 of the support vehicle 10 to mount the stemming module 200 on the end of the boom 14. Figures 13 and 14 show a marking module 300 of a system for charging a blast hole according to an embodiment of the present invention. The marking module 300 is to be 10 mounted on a support vehicle 10. In particular, the marking module 300 can be mounted on the outer end of the boom 14 of the support vehicle 10. The marking module 200 includes a magazine 302 for holding rectangular marking blocks, and an actuator 304 and gate 306 at the base of the magazine 302 for releasing 15 marking blocks individually. The marking blocks may be used prior to drilling to identify the location of the intended blast hole, and are also used after drilling to facilitate identification of the drilled blast hole. In use, the marking module 300 can be held above an intended blast hole location, and the actuator 304 operated to release a marking block onto the ground. 20 In the marking module 300 illustrated in Figures 13 and 14, the magazine 302 has capacity to hold approximately twenty marking blocks. The marking module 300 has mounts that co-operate with like mounting points on the boom 14 of the support vehicle 10 to mount the marking module 300 on the end of the 25 boom 14. Once a blast hole has been drilled, charging the blast hole can involve: 0 providing a support vehicle 10 having body 12 and a boom 14 with an inner end that is connected to the body; 30 e providing a system for charging a blast hole that includes a charge delivery module as previously described in connection with Figures 1 to 9, attaching the hose reel assembly 104 to the support vehicle 10 adjacent the inner end of the boom 14, and mounting the hose drive assembly 106 on the outer end of the boom 14; 35 0 connecting the connector 112 to a liquid explosive feed line from a supply vehicle; WO 2011/106830 PCT/AU2011/000227 -16 * locating the hose drive assembly 106 over the blast hole; " operating the second motor 118 rotate the drive wheels 116 to reel out hose 102 and push the hose 102 downwardly into the blast hole; and * passing liquid explosive material from the liquid explosive feed line through 5 the hose and into the blast hole. As will be appreciated, there is a need for the correct volume of liquid explosive material to be placed in the blast hole. For example, in a blast hole drilled to 6 metres, the charge will fill the bottom 3 metres of the hole. However, in practice, there is variation in the 10 drilled blast hole depth. Therefore, it is desirable to check the hole depth prior to charging the hole. By doing so, the correct volume of liquid explosive material can be filled, and/or the hole re-drilled, if necessary. To measure the blast hole depth (also known as "dipping" the blast hole), the hose 15 102 can be pushed into the hole 102 until the free end of the hose 102 reaches the base of the hole. In embodiments of the system in which the length of hose 102 beyond the drive wheels 116 can be determined, the depth of the blast hole can be checked. Prior to pumping liquid explosive material into the blast hole, the detonator is to be 20 located in blast hole. To this end, the detonator is placed on the platform 134 in detonator tube 128 by passing the detonator through the opening 132. When the detonator tube 128 is located over the blast hole, the platform 134 is pivoted to the release position, which releases the detonator for lowering into the blast hole. 25 To correctly locate the detonator in the blast hole (which may be approximately 1 metre above the base of the hole), the string is passed through the string tubes 140a, 140b and eyelet 142, and passed through the slit 130. Once the detonator has been released, an operator lowers the detonator on the string into position. The hose 102 can then be positioned in the blast hole for delivery of the liquid explosive material into the blast hole. 30 Once the required volume of liquid explosive material has been pumped into the blast hole, the first motor 114 is then operated to reel in hose 102 and withdraw hose 102 from blast hole. As previously described, the second motor 118 and drive wheels 116 are allowed to freewheel. 35 WO 2011/106830 PCT/AU2011/000227 -17 In addition, the cutter 144 can be operated to sever the string. The support vehicle 10 with the charge delivery module 100 can then be free to move away from the blast hole. Charging the blast hole can further involve: 5 0 providing a stemming module 200 as previously described in connection with Figures 11 and 12, and mounting the stemming module 200 on the outer end of boom 14; 0 filling bin 202 with stemming material; * locating the gate 206 above the blast hole; and 10 - operating actuator 204 to open gate 206 to release a desired amount of stemming material into the blast hole. Once the charge and stemming material have been provided, the leads of all blast holes can be tied in and the blast site readied for firing. 15 Preparation of the blast site prior to drilling the blast hole(s) can involve: * providing a marking module 300 as previously described in connection with Figures 13 and 14, and mounting the marking module 300 on the outer end of boom 14; 20 - filling magazine 302 with one or more marking blocks; * locating the magazine gate 306 above a desired blast hole site; and " operating the actuator 304 actuator to open the gate 306 and release a marking block. 25 It will be understood to persons skilled in the art of the invention that many modifications may be made without departing from the spirit and scope of the invention. For example, it is possible that the boom may be pivotally mounted about an axis lateral to the vertical so that the boom can be moved upward and downward relative to the 30 vehicle. In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive 35 sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

Claims

1. A system that charges a blast hole, the system being mountable on a support vehicle that has a body and a boom with an inner end that is movably connected to the body, the system including a charge delivery module that includes: a hose in which a flowable explosive material is conveyed; a hose reel assembly to be attached to the support vehicle, the hose reel assembly having a reel onto which the hose can be wound, and a first motor to rotate the reel; a hose drive assembly to be mounted on the outer end of the boom that provides downward delivery of the hose and the flowable explosive material into a downwardly oriented blast hole, the hose drive assembly having at least one drive wheel that is driven by a second motor and is arranged to grip the hose; and at least one hose carrier attached to the boom intermediate of the inner and outer ends of the boom, the hose carrier guiding the hose in a direction along the boom; wherein the second motor is arranged to drive the drive wheel to pay out hose from the reel and allow the hose to advance downwardly into a blast hole, and the first motor is arranged to rotate the reel to retrieve hose onto the reel and in response to relative movement of the outer end of the boom toward or away from the supply vehicle either one or a combination'of the first and second motors are operated so as to pay out hose from the reel or retrieve hose onto the reel.

2. The system according to claim 1, wherein the length of the boom is adjustable to move the outer end of the boom toward or away from the support vehicle.

3. The system according to claim 1 or 2, wherein, when the second motor and drive wheel are operated to pay out hose, the first motor is operable to control the speed of hose leaving the reel.

4. The system according to any one of the preceding claims, wherein the hose reel assembly is adapted so that the hose is wound in a flat spiral formation on the reel.

5. The system according to any one of the preceding claims, wherein the first motor is operable to retrieve the hose from the blast hole and reel the hose onto the reel at a rate so that a free end of the hose is maintained above the level of the explosive material in the hole while being discharge into the hole. 33071091 (GHMaters) P81915.PCT AXNPNMfTf QJTPFT - 19 - PCT/AU2011/000227 Received 24/04/2012

6. The system according to any one of the preceding claims, wherein a controller controls operation of either one or a combination of: i) an actuator that extends or retracts the boom; or ii) the first and/or second motors so as to payout or retrieve hose so that the hose is maintained in a linear arrangement along the length of the boom.

7. The system according to claim 6, wherein the controller controls operation of the first and/or second motors to pay-out or retrieve the hose as a function of: a the diameter of the blast hole, e the depth of the blast hole, 0 the volumetric flow rate of the explosive material within the hose.

8. The system according to claim 7, wherein the charge delivery module includes a rotary encoder associated with a rotating wheel over which the hose travels, and an output of the encoder as feedback to the controller for controlling the rate at which the hose is withdrawn from the blast hole.

9. The system according to any one of the preceding claims, wherein the hose drive assembly has a frame that facilitates mounting the hose drive assembly onto the boom.

10. The system according to any one of the preceding claims, wherein the hose drive assembly has two counter-rotating drive wheels between which the hose passes.

11. The system according to any one of the preceding claims, wherein the hose drive assembly has a guide wheel to allow the hose to freely turn on the end of the boom.

12. The system according to claim 11, wherein the guide wheel has a radius that is at least that of the minimum bending radius of the hose.

13. The system according to any one of the preceding claims, wherein the boom includes telepscopic sub-sections that interfit and move relatively to extend and retract the boom, and one of the hose carriers is attached to the outer end of each sub-section.

14. The system according to claim 13, wherein the boom is extendible and retractable and the or each carrier includes pairs of counter-rotating rollers between which the hose is guided. 33071991 (GHMatters) P81915.PCT - 20 -- PCT/AU2011/000227 Received 24/04/2012

15. The system according to any one of the preceding claims, wherein the hose drive assembly further comprises a detonator tube into which a detonator can be loaded for transport to the blast hole.

16. The system according to claim 15, wherein the detonator tube includes a platform that can be pivoted between a support position and a release position.

17. The system according to either claim 15 or 16, wherein the hose drive assembly may further comprise one or more string tubes through which a string attached to the detonator can be passed.

18. The system according to claim 17, comprising two string tubes, and the hose drive assembly further comprises a cutter for cutting the string between the string tubes.

19. The system according to any one of the preceding claims, wherein a camera is provided on the hose drive assembly to enable provision of visual information of the blast hole and certain parts of the hose drive assembly to an operator.

20. The system according to any one of the preceding claims, wherein the hose reel assembly includes an inlet pipe with one end connected to the hose and a connector at the opposite of the pipe for connection to a feed line source of explosion material.

21. The system according to claim 20, wherein the inlet pipe includes a first pivot coupling co-axial with an axis of the reel.

22. The system according to claim 20 or 21, wherein the inlet pipe includes a second pivot coupling that allows variations in relative angles between the boom and the feed line.

23. The system according to any one of the preceding claims, further including a stemming module that is mountable to the outer end of the boom, the stemming module including a bin for holding stemming material, an actuator, and a gate operated by the actuator to selectively release stemming material.

24. The system according to any one of the preceding claims, further including a marking module that is mountable to the outer end of the boom, the marking module including a 3307991 (GHMatters) P81 91 5.PCT AX4fPNnFr) qTFPT - 21 - PCT/AU2011/000227 Received 24/04/2012 magazine for holding marking blocks, an actuator, and a gate operated by the actuator for releasing marking blocks individually.

25. A method of charging a downwardly oriented blast hole using a charge delivery module having a hose, a hose reel assembly attached to a vehicle and having a reel on which the hose can be wound, and a hose drive assembly attached to an outer end of a boom extending from the vehicle and an inner end of the boom being movably connected to the vehicle, the method including: paying-out the hose from the hose reel assembly and into the blast hole by operation of the hose drive assembly; conveying flowable explosive material within the hose to discharge the explosive material into the blast hole; withdrawing the hose from the blast hole by operation of the hose reel assembly to retrieve the hose onto the reel; guiding the hose along the boom by at least one hose carrier attached to the boom intermediate of the inner and outer ends of the boom, and moving the outer end of the boom toward and away from the vehicle and in response to the movement of the outer end of the boom operating either one or a combination of the first and second motors so as to pay out hose from the reel or relative hose'onto the reel.

26. The method of according to claim 25, including controlling the rate at which the hose is withdrawn from the blast hole as a function of: * the diameter of the blast hole, 0 the depth of the blast hole, * the volumetric feed rate of the explosive material within the hose.

27. The method of according to claim 25 or 26, further including lowering a free end of the hose to the base of the blast hole to measure the depth thereof prior to conveying the explosive material into the blast hole.

28. The method of according to claim 26, wherein the charge delivery module includes a rotary encoder associated with a rotating wheel over which the hose travels and a controller, and controlling the rate at which the hose is withdrawn from.the blast hole includes use of an output of the encoder as feedback to the controller. 3307199_1 (GHMatiers) P81915 PCT A Ak fEUXTTUnT C J UT - 22 - PCT/AU2011/000227 Received 24/04/2012

29. The method according to any one of claims 25 to 28, wherein the step of withdrawing the hose from the blast hole includes rotating the reel to wind up the hose by operation of a first motor.

30. The method according to claim 29, wherein the first motor is operable to retrieve the hose from the blast hole and reel the hose onto the reel at a rate so as to keep a free end of the hose above the level of the explosive material while the material is discharged into the hole.

31. The method according to claim any one of claims 25 to 29, wherein the step of paying out the hose includes unwinding the hose from the reel and advancing the hose downwardly into the blast hole by operation of a second motor that advances the hose from an outer end of the boom.

32 The method according to any one preceding 25 to 29, wherein the hose is paid out or retrieved as the length of the boom is adjusted.

33. The method according to claim 32, wherein a controller controls operation of either one or a combination of: i) an actuator that extends or retracts the boom; or ii) the first and/or second motors so as to payout or retrieve hose so that the hose is maintained in a linear arrangement along the length of the boom.

34. The method according to any one of claims 25 to 33, wherein the hose drive assembly includes a detonator tube, and a platform within the detonator tube that is pivotable between a support position and a release position, and the method further comprises: * positioning the platform in the support position; e placing a detonator on the platform; and * once the detonator tube is located over the blast hole, pivoting the platform to the release position to release the detonator.

35. The method according to any one of claims 25 to 34, further comprising: * providing a stemming module that includes a bin for holding stemming material, an actuator, and a gate operated by the actuator to selectively release stemming material; 3307199_1 (OHMatters) P81919 PCT A nk PT 4T-TPPT - 23- PCT/AU2011/000227 Received 24/04/2012 " mounting the stemming module on the outer end of boom; e filling the bin with stemming material; * locating the gate above the blast hole; and " operating the actuator to open gate to release stemming material into the blast hole.

36. A method for charging a blast hole, the method including: providing a support vehicle having a body and a boom with an inner end that is connected to the body; providing a system for charging a blast hole that includes a charge delivery module according to any one of claims 1 to 24, attaching the hose reel assembly to the support vehicle adjacent the inner end of the boom, and mounting the hose drive assembly on the outer end of the boom; connecting the connector to a liquid explosive feed line; locating the hose drive assembly over the blast hole; operating the second motor to reel out hose and push the hose downwardly into the blast hole; passing liquid explosive material from the liquid explosive feed line through the hose and into the blast hole. 3307199_1 (GMMatters) P61915.PCT AMFND .FD SI'-IFFT