Argyle landscape

Closure

We aspire to leave a positive legacy for future generations. We do this in partnership with our stakeholders, embedding closure considerations throughout the entire lifespan of our assets – in the way we design, build, run, close and transition them.

Although mining and processing activities extend over decades, we recognise they are temporary and that other activities and land use will follow. To mitigate the impacts of a shift to a new use, we engage our stakeholders early and transparently, to contribute to a shared vision for the future of the land and associated communities. We balance environmental and social considerations with costs and look for opportunities associated with progressive closure, remediation and repurposing, and, where appropriate, long-term monitoring and maintenance. 

To realise these opportunities, we must have the basics in place. All our operating assets have closure plans aligned with our closure framework. We regularly update these plans to ensure they reflect stakeholder expectations and build on experience from closure practices as we learn from them. We have an internal assurance programme and closure plans are audited every five years against our internal requirements. At operations with joint ownership structures, we work in partnership with the asset owners to embed closure into asset design, planning and operations.

Successful closure needs to meet our host communities and long-term stewards’ expectations. To achieve this, we are working with host communities, including Indigenous partners, on rehabilitation, revegetation and long-term monitoring of the land at many sites.

Our approach to supporting regional economic development includes a strong focus on economic diversification. We endeavour to foster wider economic activities alongside national and local governments and community development plans. We provide career support and training opportunities to help the local workforce – including our own – transition to new opportunities as operations wind down. And we work with local Indigenous groups to ensure areas are looked after for future generations – right down to the kind of plants we use to regenerate land. This reflects our commitment to sustainability as well as our aim to have communities thrive long after our operations close.

In some locations, our landholdings are a significant contributor to land, water and biodiversity value. We have earmarked land for transfer to national parks and support a number of protected forests and parks across our portfolio. We are exploring options to repurpose several legacy sites for renewable energy, such as our pilot photovoltaic cell facility at Marignac, France, a former ferroalloy plant. 

Over the next five years we will transition a number of assets into closure and to their next use.

  • Argyle Diamond Mine
  • Diavik Diamond Mine
  • ERA
  • Gove Bauxite Mine

Argyle Diamond Mine

Following the last production from the Argyle mine in 2020, we are in the first year of a four-year plan to dismantle the operational infrastructure, reshape the land and undertake revegetation activities to enable the re-establishment of a natural ecosystem.

Once completed, as agreed with the Traditional Owners and the Western Australian government, we will release our landholding and support the land being returned to the Traditional Owners for activities such as cattle grazing, Indigenous cultural tourism, cultural use and possibly small-scale agriculture and native food production alongside longer-term monitoring activities. 

We are committed to support the development of long-term sustainable local businesses and local employment. Argyle continues to employ people post-mining to work on rehabilitation and monitoring, continuing to pay wages and contributing to the local economy. In 2021, we spent 14% of our closure budget with Traditional Owner business.

In 2021, the first Argyle Rangers completed their Conservation and Land Management traineeship and joined our team full time. The programme was developed to upskill Traditional Owners on various land management, community and cultural activities that will be undertaken during the closure execution phase, and post-closure monitoring and maintenance phase. Our focus is to support Traditional Owners to ultimately lead the important environmental monitoring and maintenance work required on site until approximately 2035.

Diavik Diamond Mine

We are also committed to safely and responsibly closing our Diavik Diamond Mine in Canada and have planned for its closure from the outset. We will cease production at Diavik in 2025, at which time there will no diamonds left to economically mine. We are currently undertaking detailed closure planning studies that cover not only site reclamation but also employees, communities and business transition planning.

ERA

The Ranger uranium mine in the Northern Territory is owned and operated by Energy Resources of Australia’s (ERA). ERA’s shares are publicly held and traded on the Australian Securities Exchange with Rio Tinto holding 86.3% of ERA's shares. In accordance with the Ranger s41 Authority, production at the Ranger uranium mine ceased in January 2021. 

Progressive closure of the mine is continuing. Pit 1 backfill has been completed and revegetation has commenced. The backfill of Pit 3 is progressing.

On 2 February 2022, ERA released the preliminary findings from its reforecast of the cost and schedule for the Ranger rehabilitation project, which had been subject to an independent review.  Rio Tinto is reviewing the preliminary findings of this reforecast and has advised ERA that it is committed to working with the company to ensure the rehabilitation of the Ranger Project Area is successfully achieved to a standard that will establish an environment similar to the adjacent Kakadu National Park.

Since 2012, ERA has spent more than A$683 million on rehabilitation and water management, to incorporate the Ranger mine into the surrounding Kakadu National Park.

Gove Bauxite Mine

While mining continues at our Gove bauxite operations in the Northern Territory, we are implementing progressive closure activities, including the decommissioning and demolition of the refinery and progressive capping of the red mud ponds. 

In 2021, we commenced of the capping of pond 5 within the Residue Disposal Area; completion of the feasibility study of the refinery complex; and optimisation of our waste liquor treatment plant performance. Our Closure team is working with the Gove operations team, Traditional Owners, local business, and the Northern Territory Government, to contribute to the Traditional Owners’ future vision for the Gove Peninsula, with the intention to maximise commercial opportunities that Rio Tinto has available through to closure. As agreed with stakeholders, the refinery will be demolished and the underlying land remediated so it can be used for industrial purposes with the intent that certain assets such as the light fuel farm, cargo wharf, warehouses and administration buildings may be retained for future use by Traditional Owners.

The refinery demolition is one of the largest in Australia. The Gove closure execution programme will take approximately ten years to complete followed by ongoing monitoring, with mining operations expected to cease no later than 2030.

2021 performance

In 2021, we progressed closure execution work at a number of assets including Gove refinery and Argyle, and our subsidiary Energy Resources of Australia continues to progress the closure of the Ranger uranium mine.

At the end of 2021, closure provisions on our balance sheet totalled $14.5 billion (compared with $13.3 billion in 2020). We continue to optimise closure costs through sharing good practice with product groups, finding more efficient closure execution methods, building synergies through sequential closures and targeting research and development opportunities including water and waste treatment, material movement, community engagement methodologies and partnering.

We have expanded our partnerships with universities and other organisations to find opportunities to repurpose and reprocess waste, improve water and waste treatment and explore the social aspects of mine closure. For example:

  • Together, with our partner RESOLVE we developed a business model and signed a memorandum of understanding to form Regeneration Enterprises, a “for purpose and for profit” company that will combine the remining and processing of waste with site closure and rehabilitation, with the ambition to create full restoration outcomes.
  • As part of RemovAL, a European Commission H2020 funded Innovation Action, we continue to work with ZaaK Technologies to demonstrate at pilot scale the upcycling of bauxite residue into Smart Spheres® – an engineered lightweight aggregate that can be used in a range of civil engineering applications.
  • We are a partner in the ReActiv project, which looks at new uses for bauxite residue produced during alumina refining in cement production.
  • We are a member of the Social Aspects of Mine Closure Research Consortium, an initiative of The University of Queensland’s Centre for Social Responsibility in Mining. The consortium was established in 2019 and is a multi-party, industry-university research collaboration to conduct research that challenges industry norms and practices and places people at the centre of mine closure activities.

In 2021, we completed asset closure strategies covering another six of our operating assets. These strategies are now in place for 42 assets, contributing to host communities’ vision for future land use after our operations cease and ensuring closure is considered throughout the asset lifecycle to identify opportunities while in operation.

This year, to enhance our internal governance processes, we updated our Closure Standard that outlines our minimum closure requirements to mitigate risks associated with permanent cessation of exploration, mining, processing and/or logistics operations. We also updated the internal procedure for how we estimate and report on closure costs.

Legacy sites

We also manage a number of historic sites – known as legacy sites – some we did not operate but acquired through corporate acquisitions after they were closed. Where required, we rehabilitate these sites and, where and when we can, transfer them to local authorities or third parties for future land use. In North America we are progressing the remediation of a number of sites. We have settled our obligations at the Vernon site in California and are undertaking seven studies at other sites to develop a path to divest our landholdings or optimise ongoing monitoring and maintenance.

In Europe, we are remediating the historic white and red mud deposits at Salindres, France, and have commissioned a soil treatment plant at Dammarie to enable the site to be repurposed in the future. In the UK, we continue to optimise our long-term treatment of water at Whinnyhall, a historic bauxite residue disposal site.

Two Sumatran rhinos

Turning an old gold mine into a rhino sanctuary

In 2017, our historic gold mine in Indonesia, Kelian, was assessed by the government and the World Wildlife Fund as an ideal location for the highly endangered Sumatran rhino. Part of the site has now been designated a Protection Forest and will be used as a sanctuary for housing and breeding rhino, with the aim of eventually releasing them into the wild.

More

Our Kelian team rehabilitated the 6,670-hectare gold mine site, including remediating waste dumps and building dams to protect ground and surface water from mine tailings, and converting areas that lay beneath the processing plant into a wetland.


It’s hoped the sanctuary could provide the lifeline that Kalimantan’s remaining Sumatran rhinos need to begin their recovery – and is just one example of the contribution that thoughtful closure of former mine sites can make.