Blasting system

Abstract

A blasting system wherein each of a plurality of control modules is linked to, and is used to control, a respective group of detonator assemblies, and wherein each control module can communicate with at least one concentrator which is in communication with a master controller.

Description

BLASTING SYSTEMBACKGROUND OF THE INVENTION

[0001] This invention relates to a blasting system.

[0002] Various techniques are used for implementing a blasting system which has a relatively low number of detonators or detonator assemblies. However economies of scale result when the number of detonator assemblies in a blasting system is increased. That type of increase however comes with a range of complexities including communication challenges which affect the time which is taken to implement a blasting program, for example in respect of assigning time delays to each detonator assembly and of ensuring safety of operation. A large site may have in excess of ten thousand detonator assemblies and it must be possible to address each detonator assembly independently of the others. By way of example only if the detonator assemblies are addressed sequentially with each interaction being of the order of, say, two seconds then the time needed to interact with ten thousand detonator assemblies would be of the order of five hours.

[0003] The invention is concerned with a blasting system which in one embodiment alleviates to some extent problems of communication.SUMMARY OF THE INVENTION

[0004] The invention provides a blasting system which includes a master controller in which is loaded a blast plan, a plurality of blast sites, each blast site respectively including a plurality of boreholes, at least one detonator assembly located within each borehole, a plurality of controlmodules at the blast site, each control module being linked to a specified group of detonator assemblies which are operable under control of the control module, and at least one concentrator at the blast site which is enabled to communicate with the master controller, and wherein each control module is enabled to communicate with at least one concentrator.

[0005] The master controller may include a blast controller into which is loaded the blast plan and a master module which is enabled to communicate with the blast controller using a short range communication technique, and wherein the master module and each concentrator are configured to communicate with each other.

[0006] The communication between each concentrator and the master module may be via one or more intermediate repeaters.

[0007] Communication between the master module and the blast controller may be established using any appropriate short range technique. In this respect near-field- communication (NFC) may be used to activate the master module and to provide identifiers, which are included in the blast plan, to the master module and thereafter communication may be established using WiFi.

[0008] The blast plan typically has a unique identifier which is transferred to or otherwise is stored at selected concentrators or control modules thereby to ensure that only those concentrators and control modules which are activated with the blast plan are able to communicate with one another and with the master module.

[0009] As communication can be established between the master module and each concentrator, and communication can be established between each control module and a concentrator, it falls within the scope of the invention that each control module and the master module are enabled to communicate with each other e.g. by using NFC techniques which provide or employ encryption keys, blast identifiers and radio parameters.

[0010] Communication between the master module and each control module may be established by means of long range information-bearing communication signals e.g. using the LoRa wireless communication protocol, orthogonal signalling techniques, or the like. Other communication protocols can be used. In addition to using the orthogonal signalling techniques which are employed to reduce interference between two or more control modules, concentrators or other communication units which could be operating at the same time, an exponential back-off scheme may be used to reduce the likelihood that two or more signals are transmitted at the same time. This back-off scheme embodies an algorithm which reduces the possibility of a number of communication devices operating simultaneously and consequently the probability of two or more of these devices operating in a given time slot is also reduced.

[0011] LoRa refers to a proprietary communication system which uses a spread spectrum modulation or chirp for communication. This allows for the reduction, or prevention, of interference between signals between the master module and two or more control modules.

[0012] The master controller, i.e. the blast controller and the master module, is preferably positioned at an area which is remote from the blast sites and which is safe to personnel and for equipment.

[0013] If repeaters are used then these are preferably positioned at respective locations at which the repeaters would not sustain damage when ignition of the detonator assemblies takes place.

[0014] In one respect the blasting system is based on a modular approach in which an area which typically is of a substantial size and which is to be blasted is divided into a plurality of blast sites and wherein, at each blast site, the detonator assemblies which are loaded into the boreholes at that blast site are enabled via the respective control modules and the at least one concentrator, to communicate with the master module, optionally with the aid of one or more repeaters, and hence with the blast controller.

[0015] It is possible, due to a density of installation of operational components, that a signal from a concentrator which is intended for a first control module may be received by a second control module and, conversely, a control module which expects to receive a signal from a first concentrator may receive a signal from a second concentrator. To address this aspect the invention provides that each control module according to the blast plan is assigned to a specified concentrator thereby to associate the control module with the specified concentrator, and is configured to communicate only with the specified concentrator with which the control module is associated and to ignore communication from other concentrators. This process may be effected using specific guidelines in an appropriate protocol. More than one control module may be associated with a specified concentrator. In such a manner, each concentrator effectively functions as an independent controller with each of a plurality of associated control modules being operable under control of the specified concentrator. The task of processing communication signals is thus split up and can be performed faster.

[0016] Through the use of one or more taggers or the blast controller, each control module may be tagged according to the blast plan with an identifier of a specified concentrator which, preferably, is the concentrator which is physically closest to the control module thereby to associate the control module with the specified concentrator.

[0017] Each tagger may be configured to modify the blast plan which is stored on the tagger, when required, to reflect a change which has been made at a blast site e.g. when a borehole is removed or added, or when a detonator assembly which is meant to be located within a borehole is removed from the blast site. The master controller may be operable to consolidate the changes which have been made on all the taggers so that the changes are reflected on the blast plan which is stored on the master controller.

[0018] Each control module may, in use, to preserve power, be placed in a low-power consumption mode, which, at regular intervals, is changed to an operational mode in order to scan for communication signals coming from the specified concentrator. As indicated those signals are distinguishable from other signals by virtue of an identifier which is assigned to the specified concentrator. Signals from other concentrators i.e. those signals which do not include the specific identifier are ignored by the control module in question.

[0019] It however falls within the scope of the invention for each control module which in use is unable to establish communication with the concentrator with which it is associated, after changing to the operational mode for a predetermined amount of times, to change its association to another concentrator, preferably the concentrator with the strongest signal strength relative to the control module. In that event communication with the control module is with the newly associated concentrator and not with the concentrator with which the controlmodule was initially associated. The aforegoing requires the concentrator to have been activated with the same blast plan, failing which the concentrator will not be able to identify the signal.

[0020] The association of each control module to a specified concentrator may be effected by means of signals which are sent to the tagger from the blast controller and which are based on information drawn from the blast plan. It is recognised though that due to unforeseen factors it might not be possible within the blasting system to have a configuration which complies in all respects with the blast plan. At least for this reason a facility is provided for a control module to establish communication with the master module via a concentrator which is an alternative to the concentrator which may have been associated with it in terms of the blast plan. Despite this it falls within the scope of the invention for an operator at the blast controller to transmit control signals in terms of which all components in the blasting system are placed in communication states in accordance with the blast plan.

[0021] Communication between each control module and the master module may comprise control signals from the master module to each control module, status signals from each control module to the master module, or the like. The communication is thus of a bi-directional nature. Each control module is configured upon receipt of a command signal from the master module via the specified concentrator with which the control module is associated, to execute an operation in accordance with the command signal and to ignore control signals which are received via concentrators with which the control module is not associated.

[0022] Each detonator assembly in a specified group of detonator assemblies may be linked to the control module through the use of a respective conductor.

[0023] Each control module may respectively include a transceiver for communication with a specified concentrator, a processor which is connected to the transceiver for processing control signals received by the transceiver, a memory module for storing an identifier of a specified concentrator thereby to associate the control module with the specified concentrator, a signal discriminator which is in communication with the processor for determining which other concentrator has the strongest signal strength relative to the control module thereby to allow the processor to change its association from the specified concentrator to the other concentrator if the control module is unable to establish communication with the specified concentrator, and a connection block which includes a plurality of connector terminals which are configured to receive respective ends of conductors thereby to connect each of the detonator assemblies in the specified group of detonator assemblies to the control module thereby to enable communication to take place between the control module and each detonator assembly.

[0024] Each conductor may be electrically conductive or may comprise a fibre optic cable.

[0025] A respective unique identifier of each control module may be stored in the memory module, and each concentrator or the master module may be configured to modulate control signals with the identifier of the control module thereby to enable selective communication with the control module.BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The invention is further described by way of example with reference to the accompanying drawings in which :Figure 1 schematically depicts a blasting system according to the invention, andFigure 2 illustrates a configuration at a blast site which includes a control module and a plurality of detonator assemblies.DESCRIPTION OF PREFERRED EMBODIMENT

[0027] Figure 1 of the accompanying drawings illustrates a blasting system 10 according to the invention.

[0028] The blasting system 10 includes a master controller 12 which includes a blast controller 14 into which a blast plan is loaded from a suitable control device, not shown, and a master module 16 which is located close to the blast controller 14.

[0029] The master module 16 and the blast controller 14 include communication equipment which enables these components to communicate with each other using short range communication techniques such as near-field-communication (NFC) techniques.

[0030] The blasting system 10 finds particular application in an arrangement which includes a large number of detonator assemblies which are spread over a large area. With this in mind the area to be blasted is divided into a number of blast sites or benches 20A, 20B... 20N such that each blast site 20 presents a situation which can be managed without giving rise to unwanted complexity.

[0031] At least one signal concentrator 24 is positioned at each blast site 20. The concentrator 24 is capable of long range communication with the master module 16. This arrangement allows for information pertaining to the blast plan and which is specific to theparticular blast site 20 and the detonator assemblies at that site to be exchanged between the concentrator 24 and the master module 16.

[0032] Each blast site 20 respectively includes a number of boreholes 28 and, within each borehole 28, at least one detonator assembly 30.

[0033] The detonator assemblies 30 are divided into a number of groups 32 and a respective control module 34 is linked to the detonator assemblies 30 in each group 32. The arrangement is one in which each control module 34 is enabled to communicate with one of the concentrators 24 which in turn can communicate with the master module 16 directly or, depending on distance or other environmental factors, via one or more intermediate repeaters 42 using long range information-bearing communication signals based on the LoRa wireless communication protocol.

[0034] The number of repeaters 42 in each communication route between a concentrator and the master module 16 can vary and is not necessarily the same for each route. To maintain timing accuracy it might be expected to have an equal number of repeaters in each route. However the communication technique adopted in the invention is such that timing accuracy is maintained even though the number of repeaters in each route varies.

[0035] A number of taggers 44 are used, as appropriate, in the blasting system 10. The taggers are operated by personnel at each site 20, as is known in the art. Each tagger 44 is enabled to communicate with the blast controller 12 or the master module 16, depending on location, and with each concentrator 24 or control module 34, as may be appropriate.

[0036] All communications in the blasting system 10 are implemented using suitable synchronising techniques which are enabled, for example, by means of timing signals from a differential GPS system 50, or an alternative timing mechanism which has acceptable stability and accuracy.

[0037] Figure 2 illustrates a control module 34 which includes a processor 54, a transceiver 56, a memory unit 58, a signal discriminator 60 and a connector block 62.

[0038] The connector block 62 has terminals 64A, 64B ... 64N. An electrically conductive or fibre optic lead 66 extends between each terminal 64 and a respective detonator assembly 30 which is positioned in a borehole 28 into which is charged an explosive composition 68. It falls within the scope of the invention that each lead 66 is connected to more than one of the detonator assemblies 30, not shown.

[0039] The arrangement shown in Figure 2 is implemented, as appropriate, at each blast site 20 so that each control module 34 is respectively linked to a specified group 32 of detonator assemblies 30. Each control module 34 is enabled to communicate with a concentrator 24 at the blast site 20. The concentrator 24, in turn, can communicate using long range signals with the master module 16. Where necessary, repeaters 42 are employed for this purpose. Each control module 34 is thus enabled to establish bidirectional communication with the master module 16 and thus with the blast controller 14.

[0040] Information needed to implement the blast plan is transmitted from the blast controller 14 to the concentrators 24 via the repeaters 42, where needed. Each concentrator 24 has a specified identifier and this enables the communication to be selective.

[0041] Each control module 34 in its memory unit 58 includes a unique identifier and, additionally, an identifier of the concentrator 24 with which the control module 34 is associated. The detonator assemblies 30 also include individual identifiers. Each control module 34 can then communicate with the detonator assemblies 30 in the specific group 32 linked to the control module 34 in a selective manner, using these identifiers. The control module 34 is not capable of communicating with the detonator assemblies 30 which are not in the specific group 32.

[0042] Initially, in accordance with data in the blast plan, each control module 34 is assigned a specified concentrator 24 - this is done by notifying the control module 34 of the identifier of the specified concentrator 24 thereby to associate the control module 34 with the specified concentrator 24. To preserve energy each control module 34 is kept in a low energy state but is switched to an operative state at intervals in order to scan for communication signals from the assigned concentrator 24 i.e. the specified concentrator with which the control module 34 is associated. If the control module 34 does not establish communication with the assigned concentrator 24 then the control module 34, responsive to a signal from an alternative concentrator 24, preferably the concentrator 24 with the strongest signal strength relative to the control module 34, establishes a communication link with that alternative concentrator 24 and information of that link is then conveyed to the blast controller 14. Thereafter the control module 34 does not attempt to communicate with the master module 16 via the concentrator 24 originally assigned to the control module 34.

[0043] Optionally each control module 34 in its memory 58 has stored a sequential list of identifiers of possible concentrators 24. After changing to the operative state for a set number of times, if the control module 34 is unable to establish communication with the concentrator 24to which it was originally assigned, the control module 34 uses the respective signal discriminator 60 to determine which other concentrator 24 has the greatest signal strength relative to the control module 34. The control module 34 then chooses the identifier of the concentrator 24 with the greatest signal strength from the list of identifiers to be used for communication purposes. The control module is thus associated with, or assigned to, a new concentrator 24 which has the greatest signal strength. If the control module 34 subsequently receives command signals from the concentrator 24 with which it was originally associated, those command signals are ignored. The control module 34 would only respond to command signals from the concentrator with which it is associated.

[0044] Thus, in broad terms, in accordance with the invention the area which is to be blasted is partitioned into a number of blast sites 20 and individual wireless communication channels are established between each blast site 20 and the master module 16. The arrangement is one in which long range communications with the master module 16 are effected, where necessary, using repeaters 42. The individual detonator assemblies 30 are not directly individually addressable from the master module but instead are addressable via the control module 34 which is linked to a specific group of detonator assemblies 30.

[0045] The taggers 44 are handled, as needed, by operators at the blast sites and can be used to interrogate at least, selected detonator assemblies, concentrators and control modules for programming and validation purposes.

Claims

CLAIMS1. A blasting system which includes a master controller in which is loaded a blast plan, a plurality of blast sites, each blast site respectively including a plurality of boreholes, at least one detonator assembly located within each borehole, a plurality of control modules at the blast site, each control module being linked to a specified group of detonator assemblies which are operable under control of the control module, and at least one concentrator at the blast site which is enabled to communicate with the master controller, and wherein each control module is enabled to communicate with at least one concentrator.

2. The blasting system of claim 1 wherein the master controller includes a blast controller into which is loaded the blast plan and a master module which is enabled to communicate with the blast controller and wherein the master module and each concentrator are configured to communicate with each other.

3. The blasting system of claim 1 wherein the blast plan includes a unique identifier which is transferred to, or which is otherwise stored in, at least one selected concentrator or control module thereby to ensure that in activation of the blast plan, only said concentrator or control module can communication with the master module.

4. The blasting system of claim 1 wherein communication between the master module and each control module is established by means of long range information-bearing communication signals.

5. The blasting system of claim 4 which uses an orthogonal signalling technique and an exponential back-off algorithm to reduce or prevent interference between signals between the master module and two or more of the control modules.

6. The blasting system of claim 1 wherein each control module is assigned to a specified concentrator thereby to associate the control module with the specified concentrator and is configured to communicate only with the specified concentrator with which the control module is associated and to ignore communication from other concentrators so that each concentrator functions as an independent controller with each of a plurality of associated control modules being operable under control of that concentrator.

7. The blasting system of claim 1 which includes at least one tagger which is operable to tag each control module according to the blast plan with an identifier of a specified concentrator which, preferably, is the concentrator which is physically closest to the control module thereby to associate the control module with the specified concentrator.

8. The blasting system according to claim 1 which includes at least one tagger in which is stored the blast plan and which is configured to modify the blast plan to reflect a change which has been made at a blast site, wherein said change is selected from at least the following: when a borehole is removed from or added to the blast plan; and when a detonator assembly which is meant to be located within a borehole is removed from the blast site.

9. The blasting system of claim 8 which includes a plurality of said taggers and wherein the master controller is operable to consolidate the changes which have been made on allthe taggers so that all the changes are reflected in the blast plan which is stored in the master controller.

10. The blasting system of claim 1 wherein each control module which in use is unable to establish communication with a concentrator with which it is initially associated is enabled to change its association to a concentrator with the strongest signal strength relative to the control module.

11. The blasting system of claim 1 wherein each control module is associated with a specified concentrator by means of signals which are sent to a tagger from the blast controller and which are based on information drawn from the blast plan.

12. The blasting system of claim 1 wherein bidirectional communication between each control module and the master module comprises at least control signals from the master module to each control module and status signals from each control module to the master module.

13. The blasting system of claim 1 wherein each control module is configured upon receipt of a command signal from the master module via a concentrator with which the control module is associated, to execute an operation in accordance with the command signal and to ignore control signals which are received via concentrators with which the control module is not associated.

14. The blasting system of claim 1 wherein each control module respectively includes a transceiver for communication with a specified concentrator, a processor which isconnected to the transceiver for processing control signals received by the transceiver, a memory module for storing an identifier of a specified concentrator thereby to associate the control module with the specified concentrator, a signal discriminator which is in communication with the processor for determining which other concentrator has the strongest signal strength relative to the control module thereby to allow the processor to change association from the specified concentrator to the said other concentrator if the control module is unable to establish communication with the specified concentrator, and a connection block which includes a plurality of connector terminals which are configured to receive respective ends of conductors thereby to connect each of the detonator assemblies in the specified group of detonator assemblies to the control module thereby to enable communication to take place between the control module and each detonator assembly.

15. A blasting system wherein each of a plurality of control modules is linked to, and is used to control, a respective group of detonator assemblies, and wherein each control module can communicate with at least one concentrator which is in communication with a master controller.

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