Rainfall event triggers explosives loss, exposes critical gaps in blast design and risk protocols

A Queensland mine site has suffered a serious incident involving the loss of explosives after a significant rainfall event overwhelmed blast bench drainage systems—highlighting urgent shortcomings in drill and blast planning under extreme weather conditions.

According to the latest Explosives Inspectorate Quarterly Report (April 2025), the incident occurred when heavy rain washed loaded explosives from blastholes into site drains and sumps, prompting a regulatory review of weather-readiness and control measures across the state’s mining operations.

The report reveals that water breached the designed drainage system, undermining bench stability and resulting in the uncontrolled dispersal of energetic materials. Investigators found that the bench was not designed to prevent water ingress, and that existing procedures failed to identify stop-work triggers in the face of adverse weather forecasts.

“This wasn’t just a case of poor drainage—it was a systems failure that shows how extreme weather can expose structural and procedural vulnerabilities,” the report stated.

Systemic Oversight

The Inspectorate cited multiple contributing factors:

• Inadequate bench and drainage design that failed under extreme conditions;

• No real-time weather monitoring in place to inform operational decisions;

• Insufficient controls and communication protocols to halt or modify activity when conditions deteriorated;

• Lack of contingency planning in blast design to manage water ingress.

The incident has triggered renewed calls for the sector to modernise its approach to blast design, incorporating smarter drainage layouts, enhanced risk modelling for rainfall events, and clearly defined escalation points for suspending activity.

“Proactive planning, improved decision-making, and strengthened procedures are crucial for preventing reoccurrences,” the report urged.

Recommendations for Industry

The Inspectorate recommends sites review the effectiveness of their current controls and explicitly factor in rainfall probabilities when planning blast campaigns. It also called on operations to adopt:

• Real-time weather tracking systems;

• Enhanced stemming and sump systems;

• Stronger site-specific protocols for adverse weather;

• Training for crew on escalation pathways and hazard recognition during volatile weather conditions.

Bigger Picture

This event comes as the mining sector faces increased pressure to ensure explosives safety, particularly as Queensland enters another storm season. The Inspectorate’s Safety Alert No. 453 (October 2024) and Alert No. 408 (May 2022) were referenced as critical guidance in preparing for severe weather events that threaten blast stability and site safety.

The regulator’s stance is clear: in a changing climate, reactive management is not enough.