The US Department of Energy has awarded $2.2 million of funding to a Rio Tinto-led team to explore carbon storage potential at the Tamarack nickel joint venture in central Minnesota.

Rio Tinto has assembled a team of climate innovation and research leaders to explore new approaches in carbon mineralization technology as a way to store carbon as rock safely and permanently. Rio Tinto will contribute $4 million in funding for the 3-year project, in addition to the funding from the Department of Energy’s ARPA-E OPEN 2021 program.

Carbon mineralization uses natural chemical reactions to convert captured carbon dioxide into rock and store it underground. It has the potential to be an important technology in meeting global climate goals and is now being used at large scale by the world’s leading carbon mineralization company Carbfix in Iceland.

Rio Tinto’s technical experts will work with partners including the Department of Energy’s Pacific Northwest National Laboratory (PNNL), which has demonstrated carbon mineralization technology in Washington state; Columbia University; Carbfix; and Advantek Waste Management Services.

Talon Metals, the majority owner and operator of the Tamarack Nickel Project and Rio Tinto’s joint venture partner, is contributing ore body knowledge and land access for scientific field work.

Our aim is to deliver carbon storage solutions that can help to meet climate targets by reducing and offsetting emissions from our operations and in other industries, and to explore the emerging commercial opportunities carbon storage may offer at Rio Tinto sites around the world. We will be working with leading researchers and innovators to prove the carbon storage potential of the Tamarack site and develop mineralisation solutions that can be used not just here but at other similar locations.

—Rio Tinto Chief Scientist Dr Nigel Steward

This work will leverage the knowledge gained from PNNL’s Wallula Basalt Carbon Storage Pilot Project, the only supercritical CO₂ injection in basalt demonstration in the world. We will be developing forward-looking carbon storage strategies with Rio Tinto and the broader team. PNNL stewards a suite of capabilities that allow us to look at real-time CO₂ interactions with rocks under extreme conditions.

—PNNL CO₂ subsurface sequestration expert Todd Schaef

Tamarack is a nickel, copper and cobalt project located in central Minnesota that is currently progressing towards feasibility studies. The project is managed by Rio Tinto’s joint venture partner Talon Metals, which holds a 51% share and has a right to earn-in to acquire up to 60%.

Until now, large scale carbon mineralization projects have focused on areas with certain types of rock formations known as basaltic lava geology, such as Carbfix’s sites in Iceland. In contrast, the Tamarack Nickel Project includes a large bowl of what is known as porous ultramafic rock. While this bowl sits outside the resource of nickel and other battery minerals, it has the potential to safely store hundreds of millions of tons of carbon in solid form through natural reactions.

The project will include laboratory studies and field work to confirm the carbon storage potential of the site, understand the area’s hydrology and assess different carbon mineralization technologies, developing a roadmap by 2025 to guide decisions on implementation.

The Tamarack site is also planned to host the first deployment of climate technology start-up Carbon Capture’s innovative Direct Air Capture technology, which captures carbon dioxide from the atmosphere and offers a potential supply source of carbon for mineralization. Rio Tinto has invested $4 million in Carbon Capture to support the development of its technology and feasability studies for the deployment at Tamarack are now underway.

Rio Tinto is also partnering with Carbfix to help deliver the world’s first carbon mineral storage hub in Iceland and implement carbon capture and mineral storage at the ISAL aluminum smelter.