Daunia open cut coal mine in Queensland’s Bowen Basin has broken the world record for the largest electronic detonator blast ever – firing 5665 detonators in 2683 blastholes using the AXXIS™ digital detonation system from BME.
The mine last year set a previous record for the largest AXXIS™-controlled blast to date, when it successfully initiated 4303 detonators in a single blast to break 2.8 million cubic metres of overburden.
Daunia has taken advantage of the benefits of electronic detonation to conduct larger blasts. This generates greater operational efficiencies by reducing the number of mine stoppages that must take place every time blasting is conducted.
The mine also chose this technology in response to its faulty ground conditions. If not well controlled, faults tend to slide over each other during a blast; when using non-electric detonators, there is a possibility of the product being snapped by this movement of ground before it can be detonated, resulting in a misfire.
“These misfires are eliminated with electronics, as the detonator operates as a stand-alone entity the instant you push the ‘fire’ button,” said Advanced Initiating Systems (AIS) managing director Trevor Grant. AIS is an Australian-based blasting optimisation company.
The latest record blast was prepared and carried out by Daunia staff using a single initiation point and one master control box. The blasting team was initially trained and certified by AIS, who are supplied by leading explosives firm BME. Both companies are subsidiaries of diversified agricultural, mining and chemicals group Omnia Holdings, which is listed on the Johannesburg Securities Exchange.
“The use of the AXXIS system and electronic detonators allowed the mine to better control and manage the shock waves and rock movement arising from the faulty ground conditions,” said Trevor Grant.
“The size and success of the blast demonstrates both the ease of use and the confidence that the client has in the system. Very few, if any, other electronic detonator suppliers empower clients to conduct blasts of this magnitude and complexity on their own.”
The AXXIS™ electronic delay detonators feature very high accuracy, as well as timing flexibility between detonations. The average depth of each hole in the blast was 19 metres, and the explosive was initiated from both top and bottom.
“The improved control of the blast helps keep vibration levels down,” said BME technical director Tony Rorke. “This in turn improves safety in the opencast mining environment, as high vibration levels can undermine the integrity of the pit-wall.”
To design the blast, the Daunia team used BME’s blast design software BlastMap III, which was developed as an integral part of the AXXIS™ system. The program allows complex timing designs and analysis of the results for each blast, and has just been released in an updated, second-generation version – BlastMap GII.