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Metals in Mount Isa

The city of Mount Isa is located in the North West Minerals Province, one of the world’s most mineral rich areas.

The copper and zinc-lead ores found in our region, and mined and processed at Mount Isa Mines, contain naturally occurring lead, cadmium and arsenic.

  • Lead: A soft, malleable metal. Zinc-lead-silver ore is mined at our George Fisher underground mine and processed, along with third party ore, to produce zinc and lead concentrates and lead bullion.
  • Arsenic: A grey crystalline mineral in its solid state, and also naturally occurring in water and some food in a dissolved organic form. It can be found in air or soil and is commonly associated with copper ore, its products and by-products.
  • Cadmium: A soft, ductile, silver-white or blue-white metal found naturally in zinc sulphide-based ores. It can be released through mining and smelting activities.

To protect our workforce, community and environment, we have comprehensive air quality management programs in place to minimise dust and emissions of metals and other particulates from our activities, including our processing operations, open areas and roadways.

We take a continuous improvement approach to manage our dust and emissions performance. Over the past decade, Mount Isa Mines has achieved substantial reductions in the total metal emissions generated from our site, although results can be impacted year-to-year by various meteorological and production variables.

Airborne dust and metallic particulates in air are measured as airborne particles which are referred to as ‘particulate matter’ or PM.

They include dust, dirt, smoke and liquid droplets and are measured in micrometres, a common unit of measurement used to determine particulate matter sizing. Particles with a diameter of 10 micrometres or smaller are known as PM10 and are a common air pollutant. For comparison, a human hair is about 100 micrometres in diameter.

As part of our comprehensive air quality management network, the concentration of these airborne particles are monitored at seven locations in Mount Isa using High Volume Air Samplers (HVAS).

The results recorded by these monitors are tracked against a cumulative annual limit to ensure we are operating within our regulatory limits and to minimise impacts on the community.

Our Environmental Authority specifies compliance limits for total suspended particulates and metallic particulates in air:

Indicator

Mount Isa Mines regulatory limits (annual)

Total Suspended Particulate (TSP*)

90 µg/m3

Lead (in TSP*)

0.5 µg/m3

Arsenic (in PM10 Particulates**)

0.015 µg/m3

Cadmium (in PM10 Particulates)

0.005 µg/m3


* Total Suspended Particulates (TSP) are the mass concentration of all airborne dust in an air quality sample. This dust is comprised of a mixture of particles from natural and man-made sources and is made up of particles with sizes smaller than the diameter of a human hair.

** Particulate matter (PM10) is the mass concentration of airborne dust under 10 microns in an air quality sample.

Download our year to date cumulative results (PDF 358KB) to see the HVAS site performance cumulative average reported over an annual period.

These results track our performance against our Environmental Authority (EA) limit, which is indicated by a red line at the top of each graph.

Using our NPI reporting calculations as a measure of success, we have achieved a reduction in emissions over time. We have achieved this overall reduction by significantly improving emissions capture, better identifying emission sources and procedures to control them, and have made major advances in how we respond to the release of emissions and their measured impacts, aligned with tighter regulatory limits.

2007 to 2022 metals emissions reduction

Arsenic

Cadmium

Copper

Lead

Zinc

84%

58%

93%

84%

90%

The State Government's Department of Environment and Science (DES) has real-time access to all of Mount Isa's air quality monitoring network data, as well as an independent Ambient Metals Monitor in Mount Isa.

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

Additionally, we publicly report our total emissions annually through the National Pollutant Inventory (NPI).

NPI emissions are calculated using standard emissions estimation techniques provided by the Department of Climate Change, Energy, the Environment and Water.

Emission calculations are undertaken using a combination of sampling or direct measurement, mass balance, engineering calculations and emissions factors. Direct measurement is used where available. 

The NPI calculations capture total emissions regardless of its destination, even where it remains onsite. The NPI emissions do not represent exposure to the community which is measured through our air quality monitoring system.

We are committed to continuous environmental performance. Since acquiring Mount Isa Mines in 2003, Glencore (formerly Xstrata) invested over $500m in improving our environmental performance.

We have some of the industry’s most well regarded internal and external technical specialists that provide advice and guidance on air quality performance, modelling and improvement opportunities. These factors are reported and considered as part of operational management discipline and oversight.

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