The situation

The Blast Exclusion Zone (BEZ) for personnel applied on site was variable and dependent on proximity to nearby communities. The North Wall BEZ was typically set at 500 meters.  The East Wall required a dynamic BEZ due to proximity to Sunflower village. The BEZ was adjusted based on the design stemming height and maximum instantaneous charge (MIC).  

Blasts were initiated using an Exel™ Lead-In-Line (LIL) laid toward the blasting shelter, where the shotfirer took position for protection against potential flyrock. The blasting shelter was usually towed with a loader between the two blasting areas and relocated in accordance with the BEZ indicated on the blast map.  

Records indicated an annual average of one to two misfire incidents related to the starter and primer used to fire the lead-in-line.  

Root causes included: 

• Moisture in the starter
• Misalignment of the firing pin in the starter
• Soot accumulation in the firing chamber, inhibiting signal transmission
• Occasional defective shotshell primers 

As a corrective measure, the site ensured redundancy by maintaining spare starters and shotshell primers. 

Operational safety during lead-in-line deployment was a concern. 

Personnel were exposed to hazards such as: 

• Unplanned initiation due to snap slap and shoot, or signal tube impact from rock fall near active highwalls
• Vehicle interactions during the evacuation and blast 
  clearance
• Fall from height hazards in case of multiple bench blasting, particularly when accessing upper or lower elevations with uneven floors or near the crest/free face 

"uni tronic 600 reduces the risk of accidents and injuries. Based on my own experience here on our site, the uni tronic 600 significantly streamlines the process by eliminating the need for manual relocation of blasting shelters to a safe distance, thereby using this as a cost-cutting measure that saves both time and resources. Unlike previous technologies that require an extensive setup, the uni tronic 600 allows for quick and precise remote operations."

- Leo Dayaoen, Supervisor II, Delta Earthmoving, Inc. 

Technical solutions

To address the operational and safety challenges associated with non-electric lead-in-line, Orica Technical Services explored the feasibility of a remote initiation system.  

The uni tronic™ 600 Remote Firing System was selected for its proven capability to initiate electronic detonators as starters for non-electric blasts, from a safe, remote location.  The system enables secure initiation up to two kilometers from the blast site, with extension to five kilometers using an improved antenna – making it suitable for sites with variable terrain or visual obstructions. 

To assess suitability and signal strength, multiple radio frequency (RF) tests were conducted on-site with the 
controller positioned at the new view deck. Inert training detonators were positioned at various active blast locations within the quarry.  All tests confirmed 100% reliable initiation. 

The result

On the 17th of October 2024, the first uni tronic™ 600 remotely fired blast was successfully implemented at the B+110 East Wall quarry. This served as the first successful remote firing in a quarry project nationwide, setting a precedent for future site implementations. 

The following key benefits were observed with the uni tronic™ 600  Remote Firing System:

• All blasts were initiated from locations beyond the 
  designated BEZ.
• Personnel exposure to high-risk areas during firing line setup was significantly reduced—all wired connections were less than 50m.  
• There was no requirement to deploy wires near crests, highwalls or across haul roads.
• Approximately half an hour of operational time was saved per blast through remote firing, equivalent to the time required to relocate the blast shelter with a loader. The loader was able to remain working at the stockpile area without disruption.
• There have been zero initiation incidents since the implementation. With the support of an improved antenna, the radio frequency signal was maintained consistently at 100%— providing reliable initiation. 

"We were looking forward to using remote firing with uni tronic™ 600 here at HAI. When I started, I was only familiar with the LIL system, which may put the shotfirer at risk due to the safe firing location being limited by the length of the LIL. Remote firing not only improves safety by allowing blasts to be initiated from a greater distance, but it also provides better assurance in terms of misfires by ensuring that all detonators are working and ready for blasting."

— Duane Anthony Agulay, Quarry Engineer, Helix Mining and Development Corporation

Acknowledgements

Orica extends its warmest gratitude to Delta Earthmoving Inc. and Helix Mining Development Corporation for their unwavering support towards safe practices and continuous improvement through Orica’s technology.