Abstract: The invention provides a blasting system which includes a plurality of electronic detonators which are configured in a blast array which has at least one row and a plurality of detonators in the row, each detonator including a memory in which is stored at least a respective identity code which is dependent, at least, on the row on which the detonator is, and on the detonator's position in the row, a harness which interconnects the detonators, and at least one control unit, connected to the harness, which generates a signal to fire the detonators.

Abstract: A detonator which, once armed, is automatically disarmed after a predetermined time period in the absence of at least one defined signal during such time period.

Abstract: A marker for use in a blasting system which includes a harness, the marker including a control unit, a memory in which information is stored and a connector for connection to a selected location on the harness whereby, upon receipt of an enabling signal via the harness, the information is made available by the control unit.