Sulphur Dioxide management

The roasting of gold bearing sulphide concentrate has been occurring in the Kalgoorlie-Boulder area for decades. The smelting of nickel ore has also been occurring for many years. Both processes generate sulphur dioxide. The strategies to improve air quality have been to recover the sulphur dioxide for production of sulphuric acid or to operate the roasting activity well away from the city.

Air quality in Kalgoorlie-Boulder and nearby residential areas is subject to the EPP or Environmental Protection (Goldfields Residential Areas)(Sulphur Dioxide) Policy.

The EPP defines an air quality limit for sulphur dioxide as the concentration, which shall not be exceeded. The EPP also specifies a "desirable" Standard and a limited number of events above the Standard are allowed for over any twelve-month period.

Results from the sulphur dioxide monitoring network have shown that air quality in Kalgoorlie-Boulder has improved greatly. The network is a co-operative arrangement between Auriongold - Kanowna Belle Gold Mines, WMC – Kalgoorlie Nickel Smelter and KCGM.

The monitoring network is used to measure performance against the objectives of the EPP. Monitoring data indicates that the EPP objectives are being achieved and that sulphur dioxide levels at monitoring stations are in fact zero for more than 95% of the time.

Sulphur Dioxide emissions from the Gidji Roaster are managed through the operation of an Air Quality Control Strategy. Meteorological and sulphur dioxide monitoring data are integrated into the existing process control. Alarms are triggered when adverse weather conditions are predicted or sulphur dioxide activity is detected.

Whenever elevated sulphur dioxide emissions are detected within EPP areas, KCGM reviews the conditions surrounding the event and, where appropriate, refines the control strategy to endeavour to minimise the likelihood of a recurrence of such an event in similar conditions.