Abstract: A wireless detonator system wherein a blast control unit communicates bidirectionally with at least one tagger and with detonators, prior to deployment thereof, using a NFC technique, and a transmitter/receiver assembly communicates with each detonator atan ultralow frequency.

Abstract: A detonator installation (10) in which a detonator fire capacitor (36) which is connected in series with an inductor (18) is charged from a low voltage source (16) by repeatedly opening and closing a switch (20) thereby to cause a collapsing magnetic field in the inductor (18) which results in a charging current flow to the capacitor (36).

Abstract: A detonator which is responsive to a shock tube event which is validated if a link is fused at a predetermined time interval after a light signal produced by the event is detected and if, at the end of a subsequent time interval, the link is still fused and the light signal is absent.

Abstract: A wireless detonator assembly which includes a detonator, a receiver, a printed circuit board with a stored key which is hardwired onto the board during manufacture of the detonator assembly and control logic which allows the detonator to be fired only if the control logic extracts from a signal, received by the receiver, a reference key which is identical to the stored key.

Abstract: A detonator assembly method wherein a base charge is placed into a tube to abut a closed end of the tube, an electronic module is positioned inside the tube, a displacement member with a stop formation is used to move the module, against a frictional restraining force, to a location at which the stop formation abuts a rim of the tube and wherein the module is held in position by deforming the tube into engagement with the module.

Abstract: A detonator which is used with a shock tube or a fibre optic cable and wherein an incident light signal is passed through a first impedance for communication purposes and a light signal associated with initiation of the detonator is passed through a second impedance which is less in value than the first impedance.

Abstract: A detonator which includes a housing which has a passage with an inlet and an outlet and which is of reducing cross sectional area from the inlet to the outlet and wherein the inlet is configured to be exposed to an end of a shock tube, and a fusible link is located at the outlet.

Abstract: A control circuit for a detonator which includes a charger pump with an inductor which is connected to earth via a fusible link and wherein the charge pump is placed in an operative mode to produce a charging voltage for a firing capacitor if the link is fused in response to a shock tube event.

Abstract: A detonator which is initiated by a shock tube event which is validated if a processor determines that a fusible link was not fused by a shock tube event at a predetermined time interval before light generated by the shock tube event is detected.

Abstract: A detonator which includes a tube with an open end, a shock tube, secured to a plug which is fixed to an open end of the tube, an electronic module inside the tube, the module including a substrate which carries electronic components, and sensing structure mounted to the substrate spaced from an opposing end of the shock tube.

Abstract: A wireless detonator system wherein a blast control unit communicates bidirectionally with at least one tagger and with detonators, prior to deployment thereof, using a NFC technique, and a transmitter/receiver assembly communicates with each detonator a tan ultralow frequency.

Abstract: A wireless detonator assembly which includes a detonator, a receiver, a printed circuit board with a stored key which is hardwired onto the board during manufacture of the detonator assembly and control logic which allows the detonator to be fired only if the control logic extracts from a signal, received by the receiver, a reference key which is identical to the stored key.

Abstract: A downline wire (10) serves to connect a location on the ground surface to at least one detonator (52) in a blast hole. The downline wire includes at least two flexible electrical conductors (12, 14) encased by respective flexible layers of an insulating material (20, 22) and a flexible sheath (24) in which the insulated conductors are embedded. Each conductor (12, 14) is made of a copper-clad steel core and the insulating material is either a filled flexible polyvinylchloride (PVC) composition or a polyester elastomer. The sheath (24) is made from a medium or high density polyethylene compound which includes carbon black.

Abstract: A spool for use in a blasting system which carries a coiled signal-transmitting conductor which is connected at one end to a detonator and at an opposed end to a connector.

Abstract: A blasting system which includes control equipment and a plurality of detonators which are located in respective boreholes formed in rock, wherein signals from the detonators are magnetically transmitted wirelessly through the rock to the control equipment via different paths between successive detonators, and wherein a signal from the control equipment can be simultaneously transmitted to all of the detonators.

Abstract: A method of communicating through the earth which includes the steps of using a digital pulse train to generate a sweep pulse train which controls the frequency of a magnetic field at a first location, and at a second location, detecting the magnetic field and producing a signal at a frequency dependent on the frequency of the sweep pulse train, and extracting a replica of the digital pulse train from the signal.

Abstract: A method of communicating through the earth which includes the steps of using a digital pulse train to generate a sweep pulse train which controls the frequency of a magnetic field at a first location, and at a second location, detecting the magnetic field and producing a signal at a frequency dependent on the frequency of the sweep pulse train, and extracting a replica of the digital pulse train from the signal.

Abstract: A shock tube for propagating and initiating a signal to an explosive charge which includes at least first and second elongate flexible conductors on a body of the detonator to enable two-way communication between the explosive charge and a blasting machine thereby to confirm the status of the detonator prior to sending a fire signal.