Australian export coal quality

There is a growing reference in the media by Australian politicians that Australian coal is high quality, and there is an environmental benefit in its use relative to other sources. This fact-sheet aims to provide a concise briefing on coal quality.

How is coal quality measured?

Coal is valued by the international market using one key measure, that being energy content (measured in kilocalorie/kilogram (kcal/kg), net as received (NAR)). In other words, the higher the number of kcal, the greater the amount of energy produced per kg of thermal coal.

A secondary value driver is the ash content.

Coal itself contains in trace quantities of heavy metals and other elements like Lead, Arsenic, Mercury, Selenium, Boron, Thallium, Phosphorus and Chlorine – many with cancer causing and / or toxic health impacts if released. When coal gets burned, these elements do not, so their presence is concentrated in the residual coal ash. These toxic chemicals increase the environmental risks during the processing, storage and disposal of coal ash, either by leaching into groundwater, and/or runoff, or being disposed of in streams via effluent pipes or dust.

Coal washing can reduce the ash content, and increase the remaining energy content per kilogram. Environmental disasters relating to the collapse or overflowing of coal ash waste ponds are regularly reported on, particularly after flooding, as occurred in July 2015 with devastating impact in Vietnam.

Sulphur content is a third quality factor, and generally ranges from 0-1%. Almost all Asian countries have import restrictions requiring sulphur content to be below 1%.

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