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Anglo Coal Callide Mine, A Uni tronic™ trial conversion

Anglo Coal Callide Mine, A Uni tronic™ trial conversion  

Anglo Coal’s Callide coal mining operations cover 176 square kilometers in the Callide Basin, Central Queensland, it consists of multiple coal seams, some up to 22m thick.  Anglo Coal Callide Mine produces coal primarily for domestic power generation.

Callide operates two electric walking draglines, with truckand shovel pre-stripping to remove overburden in advance ofthe dragline operations, particularly in the rugged terrain of the southern area of the mine.

The southern area of Callide’s pre strip horizons consist ofundulating hills, this makes it difficult to blast significant volumes in one bench; as a result multiple benches are oftenfired. Due to the limitations of burning fronts in conventional shock-tube initiating systems multiple benches increase the likelihood of misfires. 

The safety and production implications were considered to be too great to continue blasting this way, so an alternative solution was sought. Anglo Coal had previously seen the benefits of electronic blasting systems in their operations, with Stratablast™ trials, using the i-kon™ Electronic Blasting System, performed at Callide and Drayton Mines during 2008. 

With previous successes in mind Anglo Coal explored using the Uni tronic™ Electronic Blasting System to safely and cost effectively blast multiple benches. 

Fig 1: An example of the multiple bench blast lay out at Callide Mine.

It was chosen; firstly due to it eliminating the problem of surface cut offs, as the detonator has all of its delay information and power from the moment the fire button ispressed, regardless of it’s programmed delay time.  Secondly because of the system’s ability to identify themajority of potential misfires prior to firing. Anglo Coal Drill and Blast Engineers performed a cost comparison between the Uni tronic™ Electronic Blasting System, and their current conventional initiating system, and it was found that the price difference was negligible. 

A full and thorough Risk Assessment was completed by all stakeholders before the product was introduced on site.The blast crew was given one-day theory training on the Unitronic™ Electronic Blasting System, then several days’practical experience under the guidance of an Orica Electronic Blasting System (EBS) specialist.

For the trial the Anglo Coal Drill and Blast Engineer completed their designs as normal, then with the aid of the EBS specialist and the SHOTPlus®-UT blast design programthe timings were converted to a format for use with the Uni tronic™ Electronic Blasting System. 

Very few changes were required to loading practices,although extra care was taken to ensure the integrity of the down lines was maintained.

Fig 2: Anglo Coal blast crew loading with UT at Callide Mine

After completing several trial blasts the Drill and Blast team at Callide are seeing the following positive benefits:

  • Confidence in the increased safety for blast crew,dozer, shovel, and excavator operators operating inpre strip areas.
  • No unexpected delays due to discovery of misfires,or associated incidents and delays, during digging
    Uni tronic™ shots.
  • Anglo Coal Drill and Blast Engineers are keen startutilizing the flexible timing design offered bySHOTPlus®-UT blast design program.
  • The Anglo Coal blast crew are well on their way to being confirmed by Orica as competent Uni tronic™ Electronic Blasting System users giving them a great new skill to move in to the future of blasting!

Orica Mining Services EBS team wishes to thank the effort and support from Anglo Coal Callide’s entire Drill and Blast Department.

Author: Sri Lloyd, EBS Technician Orica Mining Services.