Recent regulatory inspections in WA have identified that workers are exposed to hazardous gas, fumes and dust from gold room exhausts discharging to walkways, accessways, air-conditioning intakes and adjacent buildings.
A mines safety bulletin recently noted that gold room exhaust contains ammonia gas, heavy metal fumes and combustion gases such as carbon monoxide and nitrous oxides generated by the electrowinning, calcining and smelting processes.
Exposures to these contaminants may lead to a variety of chronic health conditions.
The bulletin said there are a number of contributing factors, and exhaust discharges have been identified:
In walkways and accessways
Near or adjacent to air intakes
Near or towards adjacent buildings
With stacks of insufficient height to adequately disperse the contaminants
The bulletin recommended a number of required actions to minimise worker exposure to hazardous exhaust discharge:
Design stack to be high enough to achieve adequate dilution
Design, construct and maintain ventilation systems with adequate flow rate and discharge velocity
Direct discharge exhausts away from walkways, platforms and accessways
Direct discharge exhausts away from air intakes
Assess the potential for exhaust gases to enter adjacent buildings, and take action to address
Identified concerns and improvement opportunities.