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In addition to our rigorous internal monitoring and auditing processes, the State Government's Department of Environment and Heritage Protection (DEHP) has independent access to all of Mount Isa's air quality monitoring network data.

DEHP regulates our performance and is responsible for ensuring we comply with the strict conditions of our Environmental Authority (EA), and all other relevant environmental legislation.

Interpreting the results

In line with our EA, we measure and track air quality in three ways:

  1. Short-term hourly results
  2. Daily average results
  3. Annual average results

The Copper Smelter Extension Project required revision of our environmental limits under our EA. Consistent with these revisions, we are committed to maintaining and demonstrating ongoing improvements in our performance.

Mount Isa Mines operates to percentile limits on our hourly and daily sulphur dioxide exposures and we have an annual average limit.

Percentile limits restrict the number of hours or days in a year where sulphur dioxide can exceed the specified value. We are targeting performance better than these limits to maintain compliance and minimise impacts to our community.

Short-term hourly results

Under our EA, we are required to manage operational emissions to ensure sulphur dioxide concentrations in Mount Isa stay below an hourly average of 570 micrograms per cubic metre of air 98% of the time.

Daily average results

These results focus on the management of sulphur dioxide emissions averaged over a 24-hour period of exposure.

Under our EA, daily average sulphur dioxide concentration must stay below 230 micrograms per cubic metre of air, 99% of the time. We cannot exceed a daily average sulphur dioxide concentration of 230 micrograms per cubic metre of air for more than three days at any station in Mount Isa.

Our monitoring results are calculated as percentile values at each monitoring location on a calendar year basis with averaging times based on whole clock hours and calendar days.

Annual average results

Under our EA, we must achieve an annual average sulphur dioxide concentration of 57 micrograms per cubic metre of air or less. This is calculated by averaging the hourly sulphur dioxide emission values from January 1 to December 31.

Community feedback hotline

We encourage Mount Isa residents to contact our 24-hour Community Feedback Hotline on 1800 982 982 if they believe they are being impacted by our operations.

Our air quality monitoring network

Mount Isa's air quality monitoring network is one of the largest of any city in Australia.