Safety Alert

What Happened

Approximately 200 litres of sodium cyanide solution spilled from a dosing line rupture in the CIL circuit at the Processing Plant. Two operators in the immediate area were exposed to hydrogen cyanide gas at concentrations of 8ppm — above the 10-minute STEL of 4.7ppm. Both workers self-rescued using emergency escape respirators and were assessed by the site paramedic. No injuries sustained.

Why It Matters

Sodium cyanide is one of the most hazardous chemicals used in gold processing. Hydrogen cyanide gas can cause rapid incapacitation and death at concentrations above 50ppm. The workers' survival in this event was directly attributable to the availability and correct use of emergency escape respirators. Had these not been accessible, the outcome could have been fatal.

Immediate Actions Required

1. 1CIL circuit to be shut down and all cyanide dosing lines inspected for integrity before restart
2. 2Emergency escape respirators to be audited across all cyanide-risk areas — verify availability and condition
3. 3All cyanide-area workers to complete emergency response refresher training within 72 hours
4. 4Fixed HCN gas detection system to be calibrated and alarm set-points verified
5. 5Review dosing line maintenance schedule and implement predictive maintenance monitoring

Key Learning

In a cyanide emergency, seconds count. Knowing where your emergency escape respirator is and how to use it is the difference between walking away and being carried out. Check your respirator at the start of every shift, know the wind direction, and always have an escape route planned.

Discussion Points for Toolbox Talk

• •Do you know where the nearest emergency escape respirator is to your work location? When did you last check it?
• •What is the correct procedure for responding to a cyanide gas alarm?
• •How do you determine the upwind direction for evacuation? What if the wind shifts during an event?