The companies have agreed to start planning and securing permits ahead of a 2022 startup at Boron, while also exploring the potential for Heliogen deployments at Rio Tinto's other operations.
LA-based Heliogen's solar technology uses AI to control a network of mirrors that concentrate sunlight to capture energy.
The high-temperature solar technology generates steam, with the captured heat used to power nighttime operations, for instance. The Boron site currently generates steam using a natural gas cogeneration plant and natural gas-fired boilers.
"This partnership with Heliogen has the potential to significantly reduce our emissions at Boron by using this groundbreaking solar technology, and we look forward to exploring opportunities across our global portfolio," said Rio Tinto chief executive Jakob Stausholm.
Heliogen's installation will generate up to 35,000 pounds (15,875 kg) per hour of steam to power operations, reducing carbon emissions at the Boron site by around 7%. Process heat accounted for 14% of Scope 1 & 2 emissions from the Rio Tinto Group's managed operations in 2020.
Rio Tinto added that it will also be assessing the potential for larger-scale use of the Heliogen technology at Boron to reduce the site's carbon footprint by up to 24%.
Heliogen CEO and Founder Bill Gross said: "Since its founding, Heliogen has been laser-focused on decarbonizing industrial sectors, including mining. As a result, this agreement with Rio Tinto is incredibly gratifying."
Rio's Boron operation mines and refines borates into products ranging from fertilizers to construction materials. It is also producing lithium carbonate from a demonstration plant.
In 2020, the Bill Gates-backed Heliogen was granted US$39 million in Department of Energy funding to "develop, build, and operate a supercritical carbon dioxide power cycle integrated with thermal energy storage, heated by concentrated solar thermal energy supplied by a newly built heliostat field."