14 September 2020
Mount Keith Nickel Operation has one of Australia’s biggest tailings dams – and it’s also a massive mineral carbon sink.
‘Mineral carbonation’ is a natural chemical weathering process where carbon dioxide reacts with mineral rocks, such as serpentine, to form a mineral carbonate, permanently and safely locking away carbon, and reducing greenhouse gases in the earth’s atmosphere.
“In the same way trees can take up CO2, the minerals in our ore can adsorb CO2 too,” explained BHP Nickel West’s Samantha Langley, Principal Business Planning - Climate Change.
At five kilometres wide, the Mount Keith Tailings Dam in Western Australia’s northern Goldfields region currently stores approximately 40,000 tonnes of CO2 directly from the atmosphere each year.
This quantity of carbon dioxide is comparable to offsetting the annual carbon emissions of 15,000 average-sized combustion engine cars.
Researchers predict that Mount Keith could store far more CO2 every year, if the mineral carbonation rate could be enhanced through different processes and engineering solutions.
“Although mineral carbonation is a process that can take thousands of years in nature, we don’t have thousands of years to address the impacts of climate change,” said Ms Langley.
“It’s an exciting opportunity to see if we can use technology and different tailings management practices to speed up the process, and store away carbon dioxide much faster.”
BHP is now working with leading Australian and international experts to investigate methods to increase the carbonation reaction to store even more CO2 into our tailings, which will reduce or offset our operational greenhouse gas emissions and lower our carbon footprint.