When an Australian opencast coal mine wanted to eliminate the need for bulldozer push operations, while ensuring safe and productive blasting, it turned to BME for its electronic initiation solutions.
Producing seven million tonnes of coking coal annually, the mine was employing typical cast blast designs on 40 metre bench heights to achieve maximum movement of overburden material – over three million cubic metres – from each blast. A dragline, located on the low wall crest, was used to remove overburden.
Due to the nature of the geological features on the site, the mine needed to conduct a secondary or auxiliary blast to act as a locking key in the final floor surface to prevent dragline muck pile spoil creep – an important risk to manage. The blasted material was typically pushed by dozers against the main production blast face to protect the coal seam from damage during production blasting. This involved many hours of operation for this equipment, which the mine would have preferred to deploy elsewhere on the site.
According to BME’s International Technology and Field Services Manager, Tom Dermody, the mine wanted to explore how the application of electronic initiation could contribute to an efficient and sustainable solution.
“BME was asked to support the mine’s drill and blast team to optimise blasting procedures, and to look for opportunities where electronic detonators could offer downstream benefits to their operations,” said Dermody. “There were a number of goals specified by the customer, to help save costs and time – including the elimination of dozer push operations and the improvement of production blasting while still protecting the coal seam.”
To consider the options, BME carefully assessed the current blast practice, he said. It was important to understand the relationship between burden response and initiation time, for instance, to allow an opportunity to influence the final muck pile position. Using AXXIS™, BME’s flagship electronic initiation system, the blast design was refined through a series of strategic adjustments. This included redesigning the auxiliary blast to direct the throw of the material more effectively.
“The solution lay in creating a blast design that would cast the blasted material towards the production face,” he explained. “We therefore modified the powder factor and the initiation sequence to influence the ‘throw’ style blast in the required direction.”
The AXXIS™ electronic initiation system was used to influence blast movement and muck pile performance of the auxiliary blast so the material could be used to protect the coal seams of the production blast. BME was able to use advanced timing and increased powder factor into the new blasting methodology, with a focus on burden response. The accuracy and reliability of the AXXIS™ electronic initiation system also eliminated the risk of detonator mis-fires from cut-offs.
There were also significant safety benefits from the revised arrangement, he said. The dozing of blasted material to beneath the high wall was conducted under a permit system due to the higher safety risks involved.
“The new blasting technique eliminated the need for the dozer push, thus improving safety by reducing the exposure of staff and equipment,” he said. “It also allowed the equipment to be utilised more productively in other production areas.”
In addition to the savings on dozer operating hours and improved safety performance, the solution also resulted in reduced potential coal loss.
“Quantitative data after we applied our method showed cost reductions when compared to initial cost estimates and traditional blasting methods,” he said. “We were also able to achieve greater time efficiency for the mine, while ensuring a high quality of blast outcomes.”
The project highlighted the value of electronic initiation and an advanced initiation technology being applied to traditional mining challenges, said Dermody, with the solution paving the way for more sustainable and efficient mining operations.
Enabling greater operational control on site, the AXXIS™ electronic initiation system is now used in mines worldwide, improving ore recovery and setting new standards in blast precision.
