News & Media

May 2008

ELECTRONIC DETONATOR BLASTING INCREASES SAFETY AND PRODUCTIVITY

Mining activities remain a time and cost intensive business, so accurate planning and engineering have been important from the introduction of opencast blasting. In a move to improve the cost efficiency of mining operations Concor Mining has adopted the use of electronic detonation blasting (EDB) technology from a local supplier. 

An example of good fragmentation and highwall stability.

“Basic principles like two-way communication, separation of power and full control of firing energy are the minimum requirements for the user to be in control of any blast with a maximum of safety for all personnel as well as laymen in the immediate vicinity,” Concor Mining’s contracts director, Ron Beeslaar, says.  
  
The accuracy and flexibility of the programmable detonator has provided the explosives industry with options previously not available to optimise timing designs for maximum benefit in the areas of ground control and maximised fragmentation. “The industry’s whole approach to blast timing design can now be focused on greater safety for users, and increased productivity and blast performance, rather than being restricted by the limited interval selections and inaccuracies the conventional pyrotechnics timing systems offer,” Beeslaar says.

“There is a large safety factor advantage associated with using EDB,” Beeslaar says. “With traditional blasting methods one sometimes encounters out-of-sequence firing, which can lead to the generation of excessive detonation fumes and increased production of fly rock. This has definite health hazards, both for the blasters and other mining personnel, as well as people in the vicinity.

“EDB allows firing up of the detonator with an increase in rock fragmentation of 10 to 15%. It also ensures that blast holes are fired within an accuracy of 0.5 milliseconds,” Beeslaar says. “Out of sequence firing of detonators, typically associated with traditional blasting methods, results in an increase of ground vibrations, which can have negative effects on structures within the environ.”

Beeslaar says that since Concor Mining started using EDB productivity has increased by between 15 and 20%. “This is as a result of better fragmentation control as well as the fact that this methodology results in less wear and tear on capital equipment used in the pit, such as excavators, dozers and dump trucks.” Beeslaar adds that EDB has consistently provided the company with stable advanced and highwall faces with improved slope stability.

“We crush merensky and UG2 reef, so the refined technology has an impact on the crushing of the ore. This essentially means that we incur a cost saving right along the production line.”

Beeslaar says that the set-up time for both EDB and traditional blasting is the same but the planning time with EDB is reduced and the operators have more leeway to manipulate the timing of the blast as this is programmed via the software system.

“After blasting, the fragmentation analysis results can be used for a calibration of the prediction model. Input parameters are typically the type of explosives, initiation system, the rock mechanical characteristics of the ground, hole length and diameter, burden and spacing, the delay timing, etc.,” Beeslaar says.

With continuous adjustment of the prediction model over time, the quality of the prediction, for example, fragmentation, heave and the shape of the wall, become more realistic. The results of the prediction model can then be used for optimising the blast design of the electronic blasting system.

“Our blasters are currently finalising training with the technician seconded to us from our local supplier and we will continue to hire the specialised computer and software system used for planning and analysing the blasts until such time that the program development is 100% complete, at which stage we will most likely purchase our own system,” Beeslaar says.