With climate change becoming a growing issue, companies will need to incorporate more extreme weather events into mine design going forward.
During a cyclone, a mine in northern Western Australia receives almost a year’s worth of rain in 24 hours. The deluge is at least a one-in-100-year weather event.
Fortunately, the mine’s structures and waste management systems withstand the flooding. The mine owners factored in the probability of such weather as part of their climate change modelling.
But as temperatures rise each year, land at the mine becomes drier. Vegetation struggles with the heat and is less effective as erosion control. Dust and air quality become bigger issues for the mine and nearby communities.
At the same time, cyclones move further south and their intensity increases.
In 2050, a category-five cyclone crosses land. The mine receives more than a year’s rain in 24 hours.
The flooding is described as a one-in-300-year event.
The mine’s waste management systems fail during the “rain bomb”. The mine’s tailings dam collapses, releasing acidic material in waterways and damaging biodiversity. The clean-up is expected to take decades and cost hundreds of millions of dollars.
This hypothetical scenario, of course, might never happen. Much depends on mine location and the resource sector’s response to climate change risk. But mine design will have to factor in hotter temperatures and more intense rainfall events in coming decades as the climate warms.
“Extreme weather events are expected to become more frequent because of climate change,” SRK Consulting environmental geochemist Nicole Dunne said.
“Factoring in the risk of a one-in-100-year weather event into mine design and rehabilitation planning is no longer enough. Companies must also consider what a one-in-300-year weather event looks like and how that could impact their mine.”
“This a multi-generational risk. If you are planning a mine today, you need to model what the climate will look like in 2050 and beyond.”
“Even conservative climate modelling predicts the frequency and magnitude of extreme weather will increase.”