Capital expenditure at existing mine sites is undergoing an unprecedented rise, driven by an increase in demand for metals required for renewable energy products, transport infrastructure, digital devices, and data centres.
According to recent research from the University of Queensland, mine expansion is nowhere near a recent phenomenon, but the current scale and rate is solidifying as a structural feature of the global economy.
Professor Deanna Kemp, from the university’s Sustainable Minerals Institute, says policymakers urgently need to consider the long-term implications of redeveloping brownfields and what regulations need to be introduced to ensure longevity.
“Complexities around new mine projects have fuelled the brownfield expansion trend, with miners often finding it a more viable option to keep supply flowing,” Kemp says.
“This trend has social and environmental implications, and I don’t think we’ve truly considered them.”
Researchers at SMI’s Centre for Social Responsibility in Mining say the deepening trend of expanding existing mine projects was taking place amid the accepted sustainability risks of ongoing expansion as well as deferred and more complex mine closure.
Kemp says digging deeper is often coupled with a decline in the grade of the metal deposits, adding larger pits or deeper underground workings also result in greater volumes of mine waste.
“This often extends environmental impacts beyond the original project footprint, while surrounding populations may also experience incremental disruption and displacement,” she adds.
Research by One Earth reports global demand for minerals outweighs supply growth, with 366 brownfield mines in 57 countries focused on expansions.
Mineral demand is rising worldwide for renewable energy technologies such as solar, wind, and batteries, and other types of major infrastructure like transport, data centres, and digital devices.
One Earth reports at the same time, “controversy and complexity mean that building new mines is difficult, while metal recycling remains underdeveloped”.
“These pressures are driving companies to intensify and expand extraction at existing “brownfield” mines – operating deeper, larger mines for longer periods. Yet, the extent of this shift, and how it contributes to accumulating social and environmental risk, remains elusive at global scale.”
Global mineral demand is rising faster than supply growth, which One Earth says is driven by efforts to scale renewable energy, transport, digital, and defence infrastructure.
Yet, new mine commissioning has slowed, with production growth sustained by brownfield mining – expanding and intensifying extraction at existing sites.
“Because mine expansion is considered routine industry practice, questions about the global scale and scope of brownfielding are not prominent in public discussion or scientific research, limiting our understanding of its socioecological risks,” according to One Earth.
“Here, we leverage global production, exploration, and capital-expenditure data from 1998 to 2024 to uncover a decade-long acceleration in brownfield mining.
“We identify 366 brownfield mines, with 20.5% in ecologically intact or mixed landscapes, 51.5% near biodiversity or protected areas, and 77.9% above multiple high-risk thresholds, with activity concentrated in copper, gold, and iron ore in Chile, the United States, and Australia.
“A greater dependency on brownfielding requires governance that accounts for cumulative impacts and intergenerational liabilities.”
Researchers from the university say the required supply of metals is unlikely to be produced by new, large-scale projects as conversationalists, local communities, and people connected to the land address concerns.
“Simply put, it is very hard to get a new mine up and running,” Kemp says.
“If the global energy and digital transition is going to increasingly rely on mine expansion, we need to talk about how governance systems could be better set up for a future where we have larger mines that continue to be extended in different ways.”
Write to Paige Furner at Mining.com.au
Images: Adobe Stock / Jiri Castka
