TECHNICAL FIELD

[0001] The present invention relates to blasting techniques. The present invention has particular, although not exclusive application to the mining, oil and gas, and construction industries.

BACKGROUND

[0002] The reference to any prior art in this specification is not, and should not be taken as an acknowledgement or any form of suggestion that the prior art forms part of the common general knowledge.

[0003] Drilling and blasting is the controlled use of explosives and other methods such as gas pressure blasting pyrotechnics, to break rock for excavation. In practice, a number of holes are drilled into the rock in a pattern and then filled with explosives. Detonating the explosive is termed "blasting" and causes the rock to break and fragment.

[0004] After blasting, the blaster-in-charge walks the site and inspects each blasted hole. He identifies whether any of the blast holes did not fire, and gives the all clear for excavation equipment to move in once all of the holes have been properly blasted. During his inspection, the blaster in charge is walking on uneven ground which presents a slip, trip or fall risk. Furthermore, the inspection takes some time which delays the time for excavation equipment to operate on the site.

[0005] The preferred embodiment provides for safer and more efficient blast inspection techniques.

SUMMARY OF THE INVENTION

[0006] According to one aspect of the present invention, there is provided a blasting system including:

blast holes for being blasted; and

reporting means for reporting blast statuses of respective blasted holes. [0007] Advantageously, the reporting means reports the blast statuses of respective blasted holes which is safer and quicker than a manual inspection by the blaster-in- charge.

[0008] Each reporting means may be a single-use device (e.g. disposable). Each reporting means may include a shock sensor for sensing blast shock. The shock sensor may be greater uniaxial sensitivity in the direction of the blast hole than transverse to the blast hole. The shock sensor may be capable of operating across a broad

temperature range (i.e. -40°C - 85°C). The shock sensor may include any one or more of a piezo-electric device, a latching beam, a strain gauge and a micro-electromechanical system (MEMS). Alternatively, each reporting means may include a blast consumption sensor for sensing consumption of a blasting agent in the blast hole. In another embodiment, each reporting means may include an electrical sensor for sensing a change in electrical property (e.g. impedance) of a conductor to an initiator and that is indicative of a blast.

[0009] In one embodiment, each reporting means may measure a velocity of detonation (VOD). The VOD may be measured using point to point electrical

techniques, resistance wire techniques, electrical time domain reflectometry (TDR) techniques, shorted location indication by frequency of electrical resonance techniques, fibre optic point to point techniques, fibre optic TDR techniques, fibre optic light emission techniques, or fibre optic pressure detection techniques. The reporting means may include one or more geophones for monitoring ground vibrations. Readings from the geophones may be triangulated. The reporting means may include one or more heat sensors for monitoring heat signatures. The heat sensors may be mounted to one or more unmanned aerial vehicles (UAVs).

[00010] Preferably, the reporting means is electronic. Each reporting means may include a trigger circuit for triggering a transmitter responsive to sensing the blast. Each reporting means may further include the transmitter. The system may include an electrical (e.g. electric, electronic, etc) detonator or non-electric detonator (e.g. plastic tube, cap and fuse, etc).

[00011 ] The system may further include a receiver for receiving the reported blast statuses. The communications link between the reporting means and receiver may be wireless (esp. radio frequency). The system may further include a display for displaying the received blast statuses. The blast holes may form a pattern and the display may display each status in the same pattern.

[00012] The system may further include initiators in the blast holes for initiating a blast. The system may further include blasting agent in each blast hole in contact with the initiator. The system may further include stemming (e.g. aggregate) above the blasting agent for dampening upward blast or containing the blast in the lower portion of the hole. The system may further include a drill cones surrounding mouths of each blast hole.

[00013] Preferably, the reporting means is coupled to material (e.g. aggregate) within the blast hole. The reporting means may be superposed above the blast hole.

Alternatively, the reporting means may be located adjacent the blast hole.

[00014] According to one aspect of the present invention, there is provided a blasting method including:

blasting blast holes; and

reporting the blast status of each blasted hole.

[00015] Any of the features described herein can be combined in any combination with any one or more of the other features described herein within the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[00016] Preferred features, embodiments and variations of the invention may be discerned from the following Detailed Description which provides sufficient information for those skilled in the art to perform the invention. The Detailed Description is not to be regarded as limiting the scope of the preceding Summary of the Invention in any way. The Detailed Description will make reference to a number of drawings as follows:

[00017] Figure 1 is a schematic diagram of a blasting system in accordance with an embodiment of the present invention;

[00018] Figure 2 is a partial side sectional view of the system of figure 1 ; [00019] Figure 3 is a block diagram of a reporting unit of the system of figure 1 ; and

[00020] Figure 4 is a partial side sectional view of a blasting system in accordance with another embodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[00021 ] According to an embodiment of the present invention, there is provided a blasting system 100 as shown in figure 1 . The system 100 includes an array of blast holes 1 02 for being blasted. The system 100 also includes remote electronic reporting units 104 (i.e. means) for reporting the binary blast status (e.g. blasted, not blasted) of respective blasted holes 1 02. Advantageously, each reporting unit 1 04 reports the blast status of respective blasted holes 1 02 which is safer and quicker than a manual inspection by the blaster-in-charge.

[00022] The system 1 00 further includes a receiver 106 for receiving the reported blast statuses. The radio frequency (RF) communications link 1 08 between the reporting units 1 04 and receiver 106 is wireless which is more robust than wire or fibre optic alternatives. The system 100 further includes an annunciator 1 10 with a display 1 1 2 for displaying the received blast statuses. The blast holes 102 form a grid pattern and the display 1 12 displays each status (tick represents blasted hole, cross represents not blasted hole) in the same pattern. In this manner, the blaster-in-charge can rapidly and safely identify any holes 102 which were not properly blasted.

[00023] Turning to figure 2, each reporting unit 104 is coupled to aggregate 204 and superposed above the blast hole 102 using a stake, and is a single-use device (e.g. disposable) that is destroyed during the blast. The system 1 00 further includes nonelectrical or electrical initiators 200 at the base of the blast holes 1 02 for initiating a blast. The system 100 further includes blasting agent 202, in each blast hole 102, that surrounds and contacts the initiator 200. Further, the system 1 00 includes upper stemming (e.g. aggregate) 204, above the blasting agent 202, for dampening upward blast or containing the blast in the lower portion of the hole 102.

[00024] Drill cones 206 surround mouths of each blast hole 102. The drill cones 206 define voids. [00025] Turning to Figure 3, each reporting unit 104 includes a lower shock sensor 300 for sensing blast shock. The shock sensor 300 has greater uniaxial sensitivity in the direction of the blast hole 1 02 than transverse to the blast hole 1 02 so that the blasts from adjacent holes are effectively disregarded. The shock sensor 300 is capable of operating across a broad temperature range (i.e. -40°C - 85°C) to accommodate for harsh environmental conditions. The shock sensor 300 can include any one or more of a piezo-electric device, a latching beam, a strain gauge and a micro-electro-mechanical system (MEMS).

[00026] Each reporting unit 104 includes a trigger circuit 302 for immediately triggering a transmitter 304 responsive to sensing the blast shock and ahead of the significant movement of blast material. Each reporting unit 104 further includes the transmitter 304 for transmitting a unit identifier and the blast status to the receiver 106. The reporting unit 104 is sealed from moisture and dust.

[00027] Figure 4 shows another embodiment of the present invention where the reporting unit 104 is located adjacent the blast hole 102. Like reference numerals refer to like features previously described. The reporting unit 1 04 includes a transceiver that can receive blast actuation messages from the remote blaster-in-charge that electronically detonates the blasts. The messages include timing data for staging delays between blasts depending upon location in the array, arm instruction for arming the initiator 200 and a fire instruction for actuating the initiator 200 causing the blast.

[00028] The reporting unit 104 can detect detonation in a number of ways. Each reporting unit 104 can include a blast consumption sensor for sensing consumption of the blasting agent 202 in the blast hole 1 02. In another embodiment, each reporting unit 104 can include an electrical sensor for sensing a change in electrical property (e.g. impedance) of a conductor to the initiator 200 and that is indicative of a blast. In another embodiment, the reporting unit 1 04 includes one or more geophones for monitoring ground vibrations. The readings from the geophones can be triangulated to determine the blast status. In another embodiment, the reporting unit 104 includes one or more heat sensors for monitoring heat signatures. The heat sensors can be mounted to one or more unmanned aerial vehicles (UAVs) flying over the blast site.

[00029] Each reporting unit 1 04 can measure a velocity of detonation (VOD). The VOD can be measured using point to point electrical techniques, resistance wire techniques, electrical time domain reflectometry (TDR) techniques, shorted location indication by frequency of electrical resonance techniques, fibre optic point to point techniques, fibre optic TDR techniques, fibre optic light emission techniques, or fibre optic pressure detection techniques.

[00030] In practice, the blaster in charge conveniently detonates the blasts from a safe distance. After blasting, the blaster in charge used the display 1 1 2 to check each status (tick represents blasted hole, cross represents not blasted hole). If all clear, the blaster-in-charge can rapidly authorize excavation equipment into the blast site without the need for a manual inspection. If the display shows some of the holes were not blasted, the blaster in charge can rapidly identify the location of those charges and manually inspect them.

[00031 ] A person skilled in the art will appreciate that many embodiments and variations can be made without departing from the ambit of the present invention.

[00032] In one embodiment, the reporting unit 104 can include an accelerometer for sensing a blast.

[00033] In compliance with the statute, the invention has been described in language more or less specific to structural or methodical features. It is to be understood that the invention is not limited to specific features shown or described since the means herein described comprises preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted by those skilled in the art.

[00034] Reference throughout this specification to One embodiment' or 'an embodiment' means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearance of the phrases 'in one embodiment' or 'in an embodiment' in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more combinations.