Situated in the Australia’s largest coalfield, the Bowen Basin, 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 Trevor Grant, managing director of the Australia-based blasting optimization company Advanced Initiating Systems (AIS).
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 the 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 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 meters, 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 open-cast 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.
BME is a leading supplier of explosives and services to the African mining, quarrying and construction industries. Focusing on safety, supply security and value adding technical services, BME strives to remain at the forefront of technology by regularly participating in the research and trials of new blasting techniques and products, as well as attending and presenting at technical conferences worldwide. The company has operations throughout sub-Saharan Africa.