WO2021033069A1

WO2021033069A1 - Secure arming and firing in an electronic blasting system

Info

Publication number: WO2021033069A1
Application number: PCT/IB2020/057486
Authority: WO
Inventors: Andries Willem Posthumus; Anthony John Rorke
Original assignee: Omnia Group (Proprietary) Limited
Priority date: 2019-08-16
Filing date: 2020-08-07
Publication date: 2021-02-25
Also published as: ZA202202746B; AU2020333418A1; CA3151313A1

Abstract

An electronic blasting system comprises multiple detonators connected or connectable to at least one blasting box. A plurality of logging devices are used for interrogating and programming the detonators. One of the logging devices is initialised as a key logger. The key logger is the only device in or associated with the electronic blasting system that is capable of initialising each blasting box as a control unit or as a blaster unit or as a combination control unit and blaster unit, and/or of authorising arming and firing of a blast in the electronic blasting system. A method of facilitating secure arming and firing in an electronic blasting system, using the key logger, is disclosed.

Description

SECURE ARMING AND FIRING IN AN ELECTRONIC BLASTING SYSTEM

Field of the invention

The invention relates to an electronic blasting system and to a method of facilitating secure arming and firing in an electronic blasting system. The invention also relates to an apparatus for use in such a system and/or method.

Background to the invention

Detonators are employed in the blasting of rock for the extraction of minerals or other valuable components, the quarrying of rock and in civil engineering projects that require rock blasting. Blasting is generally done by drilling a pattern of boreholes, priming each borehole with a detonator and a booster and filling the hole, in accordance with the design, with commercial explosives. Types of detonators used include those attached to a pyrotechnic fuse (fuse head), electric detonators, shock-tube initiated detonators and, in the last 20 years or so, electronic detonators.

Wired electronic blasting depends on electrical leads from a blaster unit (usually near the blast) to every hole that has been supplied with an electronic detonator. The surface wiring system may comprise a lead-in line which connects to lines running along each row of holes. Connectors, usually insulation displacement connectors (IDCs), are used to connect the lead-in line or trunk line electrically to the row lines. Similar connectors may be used to connect the detonator leg wires to the row lines.

Each detonator typically comprises a metal tube containing a sealing plug, a crimp, an electronic module, a fuse head connected to the electronic module and an explosive charge.

The electronic module of modern detonators typically comprises a microprocessor, a power supply to supply regulated power to the microprocessor, a firing capacitor and a bleed resistor which acts as a shunt and drains the firing capacitor to safe voltage levels after a period of time. During preparations for a blast, one or more detonators is/are placed in each hole. The detonators are then logged, during which the operator applies a hand-held logging device, commonly referred to as a “logger” to the detonator to generate an association between the detonator’s unique electronic identity and the borehole into which it is deployed. Logging commonly also includes programming the detonator by writing a firing time for the hole in question into the detonator’s memory, testing the detonator for its readiness to fire, and recording all relevant details of the detonator in the memory of the logger.

As explained above, multiple detonators are typically connected to each other in an electronic blasting system. These form so-called multiple detonator circuits or bound networks. Blasts are usually divided into sub-circuits of, for example, about 200 to 1000 detonators. A number of these sub-circuits can comprise a single, large blast. For these large blasts, multiple loggers are generally used. Appropriate logistics and control procedures must be carried out in large blasts to make sure that every sub-circuit is energised, that all detonators are tested and ready to fire, and that every detonator receives the fire command. At some point in this process, disconnected subsets of data from the various loggers are combined into a list or data set essentially describing the entire blast. Some systems do not require this activity in order to execute the blast, but it will be appreciated that it is at least required for record keeping and/or planning purposes.

A need has been identified for an apparatus, system and/or method to facilitate or ensure secure arming and firing of a large blast.

Summary of the invention

In accordance with a first aspect of the invention, there is provided a method of facilitating secure arming and firing in an electronic blasting system, the electronic blasting system comprising multiple detonators connected or connectable to at least one blasting box, and the method comprising: providing a plurality of logging devices for interrogating and programming each detonator; and initialising one of the logging devices as a key logger such that the key logger is the only device in or associated with the electronic blasting system that is capable of carrying out one or both of: initialising each blasting box as a control unit or as a blaster unit, or as a combination control unit and blaster unit, and authorising arming and firing of a blast in the electronic blasting system; and using the key logger to initialise each blasting box and/or to authorise arming and firing of a blast in the electronic blasting system.

The key logger may thus be initialised as the only device that has final authority over a blast process.

In some embodiments, sets of information collected from the detonators in the electronic blasting system by a plurality of the logging devices are combined or consolidated into a single file in one of the logging devices, thereby initialising that one logging device as the key logger.

In some embodiments, the key logger is the only device that has the authority to initialise a blasting box as a control unit, or as a blaster unit, or as a combination control unit and blaster unit.

The key logger may be the only logging device which is configured to authorise the control unit to arm the electronic blasting system, interrogate the detonators and signal the blaster units to charge the detonators and initiate the blast.

The key logger may be configured to generate a pin, preferably a One Time Pin (OTP) or some other unique code or identifier, when or in response to it being initialised as the key logger, wherein the pin is required at critical events in the blasting process.

Critical events may be predefined and may include at least arming and firing of the blast. In some embodiments, the pin is required for: initialising a blasting box as either a control unit or as a blaster unit or as a combination control unit and blaster unit, binding a number of blaster units to a control unit, authorising the control unit to arm the system, and signalling the blaster units to charge the detonators and initiate the blast. The pin may be required to confirm each critical event. The pin is referred to as the “OTP” in the remainder of this specification. In a typical implementation, each blaster unit has a unique identity/identifier (ID), and multiple blaster units are bound to a single control unit by the key logger, wherein the key logger associates each blaster unit’s unique ID with the key logger’s OTP, for the purposes of security and control.

Preferably, the key logger carries a summary of all of the detonators and blaster units, bound to a control unit, in a single blast file which may be transferred to the control unit for purposes of identifying those blaster units that the control unit may communicate with. During communications with the control unit, any blaster unit which is activated, but whose unique ID has not been associated with the OTP, will not respond.

The key logger’s OTP survives for the duration of the blast process and once the control unit has issued a blast command, the OTP loses validity.

The logging device may be a portable logging device, also known as a logger, for use in a suitable blasting system.

In accordance with a second aspect of the invention, there is provided a logging device for use in an electronic blasting system, the electronic blasting system comprising multiple detonators connected or connectable to at least one blasting box, the logging device being configured to be initialised as a key logger, thereby configuring the logging device as the only device in or associated with the electronic blasting system that is capable of initialising each blasting box as a control unit or as a blaster unit or as a combination control unit and blaster unit and/or the only device in or associated with the electronic blasting system that is capable of authorising arming and firing of a blast in the electronic blasting system.

The logging device may be configured to receive sets of information collected from the detonators in the electronic blasting system by a plurality of logging devices, the information being combined or consolidated into a single file in the logging device, thereby initialising it as the key logger.

The logging device may include any of the further features already mentioned above and may be configured to carry out any of the method steps already described above. The logging device may be a logging device for interrogating and programming detonators in the blasting system.

The key logger may carry a summary of (or other data indicative of) all of the detonators and blaster units, bound to a particular control unit, in a single blast file. The key logger may be configured to transfer this summary to the control unit for purposes of identifying those blaster units that the control unit may communicate with.

In accordance with a third aspect of the invention, there is provided an electronic blasting system comprising: a plurality of detonators; at least one blasting box to which the detonators are connected or connectable; and a plurality of logging devices for interrogating and programming detonators in the blasting system, wherein on of the logging device is a logging device as described above for initialisation as a key logger.

The electronic blasting system may be a system for mining and/or quarrying operations.

Brief description of the drawings

An embodiment of the invention is described below, by way of example only, and with reference to the following drawings, in which:

Figure 1 is a schematic diagram of an electronic blasting system according to the invention; Figure 2 is a schematic drawing of a detonator of the electronic blasting system;

Figure 3 is a schematic drawing of a logger connected a detonator of the electronic blasting system;

Figure 4 is a schematic drawing of a logger connected to a number of detonators of the electronic blasting system;

Figure 5 is a flow diagram depicting exemplary steps in a method/process of initialising one logger out of a plurality of loggers as a key logger and initialising blaster units; and Figure 6 is a flow diagram depicting exemplary steps in a method/process of using the initialised key logger to initialise a control unit and to authorise a blast. Detailed description with reference to the drawings

The following description is provided as an enabling teaching of the invention, is illustrative of principles associated with the invention and is not intended to limit the scope of the invention. Changes may be made to the embodiment/s depicted and described, while still attaining results of the present invention and/or without departing from the scope of the invention. Furthermore, it will be understood that some results or advantages of the present invention may be attained by selecting some of the features of the present invention without utilising other features. Accordingly, those skilled in the art will recognise that modifications and adaptations to the present invention may be possible and may even be desirable in certain circumstances and may form part of the present invention.

Referring to Figure 1 , an example embodiment of an electronic blasting system (10) is shown. The system (10) comprises multiple detonators (12) connected via connectors (14) to a surface harness wire network (16) and to a blasting machine, also known as a blaster unit (18) or (19). Multiple blaster units (18, 19) are connected wirelessly, via suitably configured modems and antennas (21 ), to a control unit (20) that controls the detonators (12) through their powering, programming, calibration, arming and firing processes. In some cases, blaster units (18, 19) may be connected to each other via a two-wire cable (22) as shown in Figure 1 , e.g. for signal integrity and synchronization between units.

The blaster units (18, 19) and the control unit (20) can both be referred to as “blaster boxes”, but they have been configured to perform different functions, as is described in more detail below.

In use, at a blast site, a pattern of boreholes is drilled according to a blast design, where the parameters of each hole, including its position and firing time, are pre-assigned. Each borehole is then primed with one or more detonators (12). The detonator (12) may be inserted into a booster (not shown) to create a primer that initiates the explosive charge, alternatively the detonator (12) may directly initiate certain explosives itself. The detonator (12) is then lowered into the borehole and the hole is filled with a predetermined quantity of explosives. The hole is then charged. Each detonator (12) in the network is connected to the surface harness wire (16) via a two- core cable (24) and a connector (14).

Referring to Figure 2, each detonator (12) comprises a sealing plug (26), a crimp (28), an electronic module (30), a fuse head (32) and an explosives charge (34) which are contained inside a metal shell (36).

In this example embodiment, each electronic module (30) comprises electrostatic discharge and over-voltage barriers (38), a low-voltage power supply (40) to supply regulated power to an application specific integrated circuit (ASIC) (42) (containing non-volatile memory and a firing switch). The electronic module (30) further includes a bleed resistor (44) and a firing capacitor (46). The bleed resistor (44) acts as a shunt to drain the firing capacitor to safe voltage levels after a period of time.

The ASIC (42) has non-volatile memory that allows data to be written to and read from it during manufacturing, during programming, during testing and during the initiation of the detonator.

Referring to Figure 3, the detonators (12) are each programmed by writing a firing time and relative position into the detonator’s non-volatile memory by means of a portable logging device, referred to herein as a portable logger (60) (or simply “logger”), connected to the detonator, either via the connector (14) which connects to the logger’s connector port (62) or directly from the cable (24) to the cable ports (64) (not depicted).

The logger (60) registers each detonator’s unique identity/identifier (UID), and other details already stored in the detonator’s ASIC (42), and programs a firing time into the detonator (12), based on the detonator’s position in the blast design. Additional information, including the fact that the detonator has been positively tested, detonator position, date and time and logger ID may also be recorded on the detonator’s (12) non-volatile memory. The logger (60) also tests each detonator for current consumption, and confirmation that it has been successfully programmed, and may request further information from the detonator, including environmental measurements. In this example, the logger (60) is a handheld portable unit. It includes a touch-screen interface that is part of a robust portable microcomputer device and a separate numeric keypad for entering detonator firing time values. However, it will be appreciated that other user interfaces and designs may be employed without departing from the scope of the invention.

During logging of the detonators (12), a file is created in the logger (60), known as a blast file. This blast file typically contains a list of all detonators (12) on a blast (that have been logged by the logger (60)), with information related to each detonator (12). The information includes at least the detonator’s unique identification (UID), the detonator’s position ID (PID) and the detonator’s firing time.

Referring Figure 4, once all of the required detonators (12) have been programmed and logged, the harness wire (16) is connected to a logger (60) that contains the blast file, via the terminal points (64). The logger (60) then tests the harness (16) for power consumption and tests the detonators (60), verifying that all logged detonators (12) are present and functioning.

Testing is done either for individual detonators (12) when a logger (60) is connected to a single detonator via the connector port (62) (see Figure 3), or groups of detonators on the surface harness wires (16) when a logger is connected via the terminal points (64) (see Figure 4).

As alluded to above, the blaster units (18, 19) and control unit (20) are all “blast boxes”. In this example embodiment, all blast boxes (18, 19 and 20) are identical in structure, possible functionality, software and electronics. However, individual boxes are configurable based on their required application and must be initialised as either a control unit or a blaster unit or combination thereof during preparation for undertaking a blast.

A blaster unit (18,19) requires wireless communication with a control unit (20) to allow firing of detonators (12).

Referring to the flow diagram (70) in Figure 5, where a number of loggers (60) are used in the blasting system (10), the loggers (60) are activated and each used for logging and testing of detonators (12) associated (or to be associated) with different blaster units (18, 19), at stage (71).

At stage (72), once logging and testing of detonators (12) has been completed, all the blast files from the different loggers (60) are combined or consolidated into one file on one of the loggers (60). This file may be referred to as a key blast file. This process initialises that one logger as the key logger, at stage (73). The key logger is configured such that, once it has received/generated the key blast file and is initialised as the key logger, it generates a One Time Pin (OTP) which is valid for the duration of the blast. The term “OTP” should be broadly interpreted and may be any suitable pin, passcode, password, or the like.

In this example embodiment, when a blasting box is switched on, it defaults to an “unconfigured state” and must be initialised as a blaster unit by the key logger at stage (74). A blaster unit (18,19) cannot fire a blast, test detonators, re-program detonators, or power up the line unless it is in a bound network of units with an initialised control unit (20). The key logger binds the units by creating a blast file, or box list, which defines each blaster unit to be used on the blast by the blaster unit’s unique ID and the OTP number (stage (75)).

In this example, once stages (71)-(75) have been carried out, the loggers (60) are switched off / deactivated (stage (76)).

The key logger is the only logger (60) that will carry the key blast file containing information about the detonators (12) and the blaster units (18,19) associated with and/or bound to a single control unit (20).

Referring now to the flow diagram (80) in Figure 6, the key logger is the only logger (60) that is configured to (and thus able to) authorise a blasting box as a control unit and the key logger initialises one control unit in a bound network of blasting boxes (see for example the control unit (20) in Figure 1 ). The key logger and relevant blasting box are activated (stage (81) and (82)) and once the control unit (20) has been initialised, the blast file and OTP is transferred from the key logger to the control unit (20). The blast file contains a list of blaster unit IDs to be used and controlled by the control unit (20) in the blast (see stages (83) and (84)). The OTP survives for the duration of the blast process. Once the control unit (20) has issued a blast command, the OTP loses its validity.

Once the control unit (20) has been initialised, it is switched to standby mode at stage (85) and communication channels to all of the relevant blaster units (as defined by the blast file) are opened at stage (86).

The system (10) is armed with authorisation from the key logger on manual entry of the OTP (stage (87)). The control unit then instructs the blaster units to power the detonators (12) up via the surface harness wires (16), charge firing capacitors and start test sequences (stage (88)).

Once the detonators’ firing capacitors have been charged by the blaster units (18,19), the blaster units (18, 19) issue repeating test sequences to the detonators (12). In some embodiments, testing is done by exception. In other words, detonators (12) will only respond to a test if something is wrong.

During the execution of a blast, a system status is continuously or periodically uploaded to the key logger from the control unit (20) and at least the following information can be displayed on the key logger’s screen: current activity, fault reporting, armed or safe condition and countdown to blast.

As each blaster unit (18, 19) runs through the testing routines, it reports the test results to the control unit (20), which then relays this information to the key logger. The key logger will report if a blast must be aborted and will report on any detonator failures. Specific test requests can be made from the key logger. In this example embodiment, although the key logger cannot issue a “charge capacitors’’ command or a “fire” command, it is configured to authorise the control unit (20) to carry out these commands though the manual entry of the OTP in the key logger.

All powering-up of detonators (12) at firing voltage, calibrating, charging of firing capacitors and issuing of the blast command is done from the control unit (20) with authority from the key logger. It can thus be said that the key logger has final authority over at least the abovementioned aspects of the blasting process. All commands are issued to the detonators (12) from the control unit (20) via the blaster units (18,19) in the bound network. Once the “fire command’’ has been authorised by the manual entry of the OTP on the key logger (stage (89)), the operator has a limited window of time in which to fire the blast from the control unit (20) at stage (90). Once the blast is fired, the OTP loses its validity. The operator will then deactivate the key logger and blasting boxes at stage (91 ). Embodiments of the invention thus provide an apparatus, system and method to facilitate or ensure secure arming and firing of a blast, and particularly a large blast with multiple sub circuits.

This is achieved by launching or initialising one logger amongst a group of loggers in an electronic blasting system as a key logger, in such a manner that the key logger is (i) the only logger configured to initialise blasting boxes as control units or blaster units and/or (ii) the only logger that can be used to authorise arming and firing of the system via the control unit.

Claims

1. A method of facilitating secure arming and firing in an electronic blasting system, the electronic blasting system comprising multiple detonators connected or connectable to at least one blasting box, and the method comprising: providing a plurality of logging devices for interrogating and programming the detonators; and initialising one of the logging devices as a key logger such that the key logger is the only device in or associated with the electronic blasting system that is capable of carrying out one or both of: initialising each blasting box as a control unit or as a blaster unit, or as a combination control unit and blaster unit, and authorising arming and firing of a blast in the electronic blasting system; and using the key logger to initialise each blasting box and/or to authorise arming and firing of a blast in the electronic blasting system.

2. The method according to claim 1 , which includes initialising the key logger by combining or consolidating sets of information collected from the detonators in the electronic blasting system by a plurality of the logging devices into a single file in the one logging device.

3. The method according to claim 1 or 2, wherein one of the blasting boxes is initialised as a control unit and a plurality of the blasting boxes are initialised as blaster units, and wherein the method includes initialising the key logger as the only device configured to authorise the control unit to arm the electronic blasting system, interrogate the detonators and signal the blaster units to charge the detonators and initiate the blast.

4. The method according to claim 3, wherein the key logger carries a summary or other data indicative of all of the detonators and blaster units, bound to the control unit, in a single blast file, and wherein the method includes transferring the blast file to the control unit for purposes of identifying those blaster units that the control unit may communicate with.

5. The method according to any one of the preceding claims, which includes generating, by the key logger, a One Time Pin (OTP) when initialised or in response to being initialised as the key logger, wherein the OTP is required at critical events in a blasting process of the electronic blasting system.

6. The method according to claim 5, wherein the OTP is required for one or more of: initialising a blasting box as either a control unit or as a blaster unit or as a combination control unit and blaster unit, binding a number of blaster units to a control unit, authorising a control unit to arm the electronic blasting system, and signalling blaster units to charge the detonators and initiate the blast.

7. A logging device for use in an electronic blasting system, the electronic blasting system comprising multiple detonators connected or connectable to at least one blasting box, the logging device being configured to be initialised as a key logger, thereby configuring the logging device as the only device in or associated with the electronic blasting system that is capable of initialising each blasting box as a control unit or as a blaster unit or as a combination control unit and blaster unit and/or the only device in or associated with the electronic blasting system that is capable of authorising arming and firing of a blast in the electronic blasting system.

8. The logging device according to claim 7, which is configured to receive sets of information collected from the detonators in the electronic blasting system by a plurality of logging devices, the information being combined or consolidated into a single file in the logging device, thereby initialising it as the key logger.

9. The logging device according to claim 7 or 8, wherein, in the electronic blasting system, one of the blasting boxes is initialised as a control unit and a plurality of the blasting boxes are initialised as blaster units, and wherein the logging device, after being initialised as the key logger, is the only device configured to authorise the control unit to arm the electronic blasting system, interrogate the detonators and signal the blaster units to charge the detonators and initiate the blast.

10. The logging device according to claim 9, wherein the key logger carries a summary or other data indicative of all of the detonators and blaster units, bound to the control unit, in a single blast file, and wherein the key logger is configured to transfer the blast file to the control unit for purposes of identifying those blaster units that the control unit may communicate with.

11. The logging device according to any one of claims 7 to 10, which is configured to generate a One Time Pin (OTP) when initialised or in response to being initialised as the key logger, wherein the OTP is required at critical events in a blasting process.

12. The logging device according to claim 11 , wherein the OTP is required for one or more of: initialising a blasting box as either a control unit or as a blaster unit or as a combination control unit and blaster unit, binding a number of blaster units to a control unit, authorising a control unit to arm the electronic blasting system, and signalling blaster units to charge the detonators and initiate the blast.

13. An electronic blasting system comprising: a plurality of detonators; at least one blasting box to which the detonators are connected or connectable; and a plurality of logging devices for interrogating and programming detonators in the blasting system, wherein one of the logging device is initialised as a key logger according to any one of claims 7 to 12.

14. The system according to claim 13, wherein one of the blasting boxes is initialised as a control unit and a plurality of the blasting boxes are initialised as blaster units, wherein each blaster unit has a unique identity (ID), and wherein multiple blaster units are bound to the control unit by the key logger.

15. The system according to claim 14 when dependent on claim 11 or 12, wherein the key logger associates the unique ID of each blaster unit with the OTP of the key logger for security and/or control purposes.