During maintenance on an underground long-hole drill rig, a drill boom suddenly fell and struck a worker, knocking them from their work platform to the ground. The drill’s horseshoe frame partially arrested the boom’s descent, preventing it from fully collapsing onto the worker. The worker then self-extricated from beneath the structure.
At the time of the incident, workers had secured the drill boom using a come-along device and already removed some bolts or fasteners holding it in place. The securing device failed under load, allowing the boom to drop unexpectedly.
Although the worker did not sustain life-threatening injuries, the incident exposed them to a significant line-of-fire hazard and carried clear potential for fatal consequences.
Takeaways
- Avoid relying solely on temporary restraint devices: Come-alongs and similar tools may not provide adequate load security.
- Use engineered supports: Deploy rated, purpose-designed systems to prevent uncontrolled movements of suspended or partially dismantled components.
- Eliminate line-of-fire exposures: Keep workers out of fall zones and away from inadequately secured loads.
- Conduct thorough pre-task assessments: Identify load weights, centres of gravity and appropriate securing methods before starting jobs.
- Sequence fastener removals: Ensure redundant supports are in place before releasing any components that may shift or fall.
Summary
Maintenance work on underground plant equipment involving suspended or partially supported components carries significant risks of crushing injuries and fatalities. Inadequate load-securing arrangements and insufficient planning can result in sudden, high-consequence incidents. To prevent serious injuries or fatalities, implement effective load-support systems, eliminate line-of-fire exposures, conduct rigorous risk assessments and promote strong safety intervention behaviours.
