Question 7 of 7: Accident Case Analysis — Die-Rigging Keeper-Pin Shear

Question 7: Accident Case Analysis — Die-Rigging Keeper-Pin Shear (20 marks: 7/7/6)

Question text not reproduced: the examination questions are © Engineers and Geoscientists BC. Open the official past paper (linked at the top of this page) to read the question, then follow the worked solution below.

(i) Cause of the Accident

• Immediate cause — the chain was rigged against the keeper pin instead of the rated die notch/lifting point; taking up the slack sheared the pin, which flew and struck the worker.
• Root/contributing causes: improper rigging (load on a component not designed to bear it); no verification (the rigging was not double-checked); poor communication/coordination (lift signalled while the worker was not clear); the worker in the line of fire of the tensioned rigging; procedure/training gaps.

(ii) Corrective Actions

• Safe rigging procedure — attach only to designated rated lifting points; use correctly rated slings/chains; verify before load is applied.
• Independent check — a second person/supervisor verifies rigging before lifting ("no lift until checked").
• Signalling protocol — one designated signaller; lift only on a clear signal after confirming everyone is clear.
• Keep clear / line of fire; training in rigging, signalling and crane safety.

(iii) Follow-Up

• Investigate and document (root-cause analysis); report as legally required.
• Implement corrective actions; write/update the safe-rigging and signalling procedure; retrain riggers/operators; audit lifts.
• Review similar operations plant-wide; monitor for recurrence; support the injured worker; share lessons learned.