Rio Tinto PLC has agreed to collaborate with environmental technology company Calix to test its low-emission ironmaking process in Western Australia, acknowledging that its proprietary BioIron technology requires further refinement.

The mining giant announced on Monday that it signed a joint development agreement to support Calix's plans for a Zero Emissions Steel Technology (ZESTY) demonstration plant. The facility may be constructed at a site south of Perth, where Rio Tinto previously intended to establish its BioIron research facility and pilot plant.

Rio Tinto will invest over A$35 million (US$23 million) to help develop the demonstration plant. If approved, the company will also supply up to 10,000 tonnes of iron ore from its Pilbara operations for the plant's commissioning and initial testing.

The ZESTY process utilizes electric heating and hydrogen reduction technology to produce low-emission iron. Calix has additionally secured a A$44.9 million grant from the Australian government for this initiative.