Detonation of explosives

An explosives detonator system for detonating an explosive charge with which it is, in use, arranged in a detonating relationship and which, on operative acceptance of a detonation initiating signal that has a detonation initiating property, is capable of initiating and thus detonating the explosive charge, the detonator system including

• an initiating device which is capable of accepting the detonation initiating signal and of initiating and thus detonating the explosive charge, the initiating device being in a non-detonation initiating condition in which it cannot operatively accept the detonation initiating signal and thus assume a detonator initiating condition when the detonation initiating signal is transmitted thereto;
• and
• a switching device that is capable of detecting a chemical compositional component as a switching property of a switching signal that is transmitted to the detonator system, with the switching device being capable of switching the initiating device, on detection of the chemical compositional component, to a standby condition in which the initiating device is capable of operatively accepting the detonation initiating signal when it is transmitted thereto.