Closure: towards a positive legacy

Meeting our responsibilities at legacy projects

Sometimes we become accountable for sites we may not have operated, but which have become part of our portfolio through mergers or acquisitions or otherwise.

This was the case with the historic Holden Mine in Lake Chelan, Washington, US – one of the largest operating copper mines in the country until it closed in 1957. While it was never owned or operated by Rio Tinto, we assumed responsibility for its remediation when we acquired Alcan.

In 2009, our team began a $500 million federally mandated remediation project to address issues including decaying infrastructure and mine waste seeping into groundwater, polluting the adjacent river and damaging the surrounding environment, including wetlands.

Nestled in a remote part of the Cascade Mountains, accessible only by water, the mine’s historic village is now a Lutheran community and spiritual retreat centre, which is also a popular tourist destination. It was essential that we work closely with the local community to ensure the remediation process minimised disruption for residents, guests and recreationalists.

To address environmental impacts, we reshaped and covered around eight million tonnes of tailings and waste rock piles and built a barrier to contain and divert polluted groundwater to a newly constructed water treatment plant. We continue to monitor the ongoing environmental impact of the site to ensure any risks and issues are contained.

Addressing challenges that can’t be fixed

Remediation has the potential to impact the surrounding environment. Even after carefully working to minimise impacts, some wetland areas were still impacted during the necessary remediation.

“Wetlands existed across the site, including in areas that needed remedial action,” says Steve, General Manager, Closure Americas.

“And unfortunately, some damage was unavoidable to ensure access to the site, regrade waste piles and build the facilities needed for remediation.”

To help us address the impacted wetlands, we worked with the USDA Forest Service, their partner agencies – including the US Environmental Protection Agency, Washington Department of Ecology, and US Fish and Wildlife Service – and the Yakama Nation.

In 2021, we contributed to the purchase of a 2,100-acre property that has similar ecological characteristics to the disturbed land at Lake Chelan. The property – which will be managed permanently by Chelan-Douglas Land Trust and solely used to conserve native species and habitats – includes at least four acres of wetlands and a large tract of upland forest habitat, surrounded by United States Forest Service land. The Chelan-Douglas Land Trust will manage the land, named the Chelan Coulees Reserve, with an emphasis on fire safety, wetland preservation, adaptation to climate change, and habitat for wildlife. Its location presents a unique opportunity to conserve connected lands that will now never be developed or fragmented into multiple small ownerships.

“By supporting the permanent conservation of this important wildlife reserve, we aim to deliver lasting environmental outcomes for the Lake Chelan area. This builds on the transformation we have seen with the remediation of the Holden site, which is a great source of pride for us,” says Steve.

“Our goal is to leave a positive legacy for future generations, taking into account environmental and community considerations.”