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How old mines became havens for nature

Minerals and metals are vital for the world’s economy and in underpinning the world’s transition to sustainable and clean energy provision.

While disturbance to local areas is inevitable in any mining operation, ICMM members are committed to ensuring mine sites are closed responsibly, to minimise legacy impacts on environment and to help restore and regenerate nature in consultation with local communities.

In the third of the four-step mitigation hierarchy, “restore”, ICMM members are working to ensure their closed mine sites are not only safe and non-polluting to local communities, but that they also provide a space for nature to regenerate and thrive. This forms part of a commitment to achieving no net loss of biodiversity across mine sites by closure from a baseline of 2020 or earlier.

People and wildlife

In Saskatchewan, Canada, the Cluff Lake uranium and gold mining project ended in 2002. Orano engaged extensively with local communities, Indigenous People including the Métis, other key stakeholders to plan the decommissioning work, which finished in 2006, with the goal of making the area safe and stable for the future.

To start, contaminated water was treated, mined out pits were flooded to create lakes, and over 650,000 trees were planted. Waste rock and tailings were covered with a minimum of one metre of topsoil to enable vegetation to grow, and those areas were shaped and compacted to minimise the amount of water that might flow through them, to avoid washing contaminants into the environment.

Almost 20 years later, the site restoration is a success with the site being legally transferred to the Province of Saskatchewan and people now using the land for hunting, fishing and camping.

Water quality monitoring shows that it meets agreed standards, and that the animals, fish and plants there are safe to eat. 

Achieving the impossible

The Mount Rosser bauxite residue site in Jamaica was once an 87-acre lake of contaminated water above nine million cubic metres of red mud. Red mud is the waste that remains after aluminium is extracted from bauxite – it contains high levels of sodium, as well as silicon, iron and titanium.

Although bauxite mining had ended in 1991, Rio Tinto took over responsibility for the restoration of the site when it acquired the mining company Alcan in 2007. Previously, remediation of red mud involved drying it out and fencing it off, or bringing in countless tonnes of topsoil from other areas to cover it.

Instead, the company decided to try an innovative method to transform the red mud into topsoil. First, they removed and treated the water, then trialled small plots – adding gypsum to lower the soil’s acidity, as well as chicken manure fertiliser, and introducing hardy plants with a focus on those that are native to Jamaica.

The area was barren when planting started in 2016 but today 100 per cent of the land is covered in self-sustaining vegetation which supports animal life, including ants and butterflies. The range of vegetation now includes the planted varieties, as well as those that have self-seeded from nearby areas, including wild sage and wood sorrel, indicating a true integration with the natural environment.

The restoration of mine sites is a long and often complex process, and it is vital that it is conducted with the inclusive engagement of local stakeholders. The stories of regeneration in this article show how, through innovation and careful nurturing, ICMM members have been able to bring nature back to decades-old sites, providing them with a healthier, brighter future.