Electronic blasting system

1. An electronic blasting system comprising:

a control unit;

a surface harness; and

electronic detonators connected to the surface harness by a 2-wire lead, the detonators being adapted to provide information to the control unit in response to command signals transmitted by the control unit along the surface harness;

wherein the surface harness includes actuators that enable the control unit to communicate with individual unknown detonators so that the arrangement of detonators can be determined by the control unit, and wherein communication between the control unit and individual detonators can be bi-directional.

2. An electronic blasting system according to claim 1 , wherein the surface harness comprises a primary line with trunk lines connected to it, wherein each trunk line has connected to it individual detonators making up the same row, wherein each trunk line is connected to the primary line by an actuator, and wherein each trunk line includes an actuator between adjacent detonators.

3. An electronic blasting system according to claim 2 , wherein multiple trunk lines are connected to the primary line by a single actuator with this actuator enabling each trunk line to be accessed sequentially by the control unit.

4. An electronic blasting system according to claim 1 , wherein at least one actuator has the ability to communicate to the control unit its existing operating state and/or whether a change in operating state has been successfully effected.

5. An electronic blasting system according to claim 1 , wherein each actuator has the ability to communicate to the control unit its existing operating state and/or whether a change in operating state has been successfully effected.

6. An electronic blasting system according to claim 1 , wherein at least one actuator

has the ability to perform diagnostics on local wiring and detonators, and to report the results thereof to the control unit.

7. An electronic blasting system according to claim 1 , wherein at least one actuator is able to perform signal amplification to ensure that command signals emanating from the control unit have sufficient strength and integrity to be acted upon across the entire blasting system.

8. An electronic blasting system according to claim 1 , wherein the state of each actuator may be changed in a reversible fashion in response to appropriate command signals.

9. An electronic blasting system according to claim 1 , wherein each actuator comprises a switch.

10. An electronic blasting system according to claim 9 , wherein the switch is integrated in an application specific integrated circuit (ASIC).

11. An electronic blasting system according to claim 9 , wherein the switch is implemented as a field effect transistor.

12. An electronic blasting system according to claim 1 , wherein an actuator is associated with a component of the blasting system and information relating to this association is stored in the actuator and accessible by the control unit.

13. An electronic blasting system according to claim 12 , wherein the actuator includes information relating to a detonator with which it is associated.

14. An electronic blasting system of claim 1 , wherein the surface harness is a 2-wire lead.

15. A method of blasting in which an electronic blasting system as claimed in claim 1 is implemented in order to allow an arrangement of detonators to be determined.

16. A method according to claim 14 further comprising programming of individual detonators with delay times based on the arrangement of detonators so-determined.

17. A method according to claim 16 , wherein determination of the arrangement of detonators and programming of the detonators is undertaken remotely by a control unit.

18. A method of blasting which comprises installing an electronic blasting system as claimed in claim 1 .

19. A method according to claim 18 , further comprising the step of programming individual detonators with a time delay.