Velocity of detonation measurement
AssigneeDetnet South Africa (Pty) Ltd
InventorsMichiel Jacobus Kruger, Marinus Yates, Daniel August Julien Louis Maurissens, Brian E. Petted
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Abstract
A method of obtaining velocity of detonation (VOD) information from a borehole wherein an explosive in the borehole is ignited by initiation of a detonator, the method including the steps of using a control circuit which obtains a measurement of the VOD and which is subsequently destroyed by ignition of the explosive, and of transmitting from the borehole a wireless signal which contains the VOD measurement and data which identifies the borehole before the control circuit is destroyed.
Claims11
A blasting system comprising:
- a plurality of detonator assemblies, a blast controller and at least one receiver, wherein each detonator assembly includes a detonator which, in use, is positioned inside a borehole which is charged with an explosive, a communication module and conductors which connect the detonator to the communication module, wherein the detonator in response to a fire command signal from the blast controller received by the detonator at a time A is initiated at a time B to cause ignition of the explosive in the borehole, and wherein the communication module includes a control circuit which is configured to obtain a measurement of the velocity of detonation (VOD) of the explosive which is based on a resistance value which is presented by the conductors to the control circuit, and which is indicative of a predetermined length of the conductors consumed by the ignited explosive and a transmitter for transmitting to the receiver a wireless signal which commences at the time B and is maintained for a time period until the predetermined length of the conductors is consumed by the ignited explosive, and wherein the time period for which the wireless signal is transmitted is indicative of the VOD measurement and is reduced to a minimum to assist in discriminating between the wireless signal and respective wireless signals transmitted from other detonator assemblies of the plurality of detonator assemblies, and wherein the wireless signal contains identification information which identifies the detonator assembly from which the wireless signal was transmitted before the transmitter is destroyed by the ignited explosive.
A method of obtaining velocity of detonation (VOD) information from each of a plurality of boreholes in a blasting system which comprises a plurality of detonator assemblies, a blast controller and at least one receiver, wherein each detonator assembly includes a detonator which, in use, is positioned inside a respective borehole of the plurality of boreholes, a communication module and conductors which connect the detonator to the communication module which includes a control circuit, wherein each borehole is respectively charged with an explosive which is ignited by initiation of the respective detonator in the borehole at a time B in response to a fire command signal from the blast controller received by the detonator at a time A, the method comprising the steps, at each borehole, of:
- using the respective control circuit which is associated with the respective detonator to obtain a measurement of the VOD of the explosive which is based on a resistance value which is presented by the conductors to the control circuit, and which is indicative of a predetermined length of the conductors consumed by the ignited explosive;
- and transmitting from the borehole to the receiver a respective wireless signal which commences at the time B and is maintained for a time period until the predetermined length of the conductors is consumed by the ignited explosive, and wherein the time period for which the wireless signal is transmitted is indicative of the VOD measurement and is reduced to a minimum to assist in discriminating between the wireless signal and respective wireless signals transmitted from other detonator assemblies of the plurality of detonator assemblies and wherein the wireless signal contains data which identifies the borehole.
Dependencies are inferred from the claim text.