Rio Tinto developed BioIron™ technology for low-carbon steelmaking, replacing coking coal throughout sustainable biomass & microwave energy. The patent-pending process converts iron ore into metallic iron using lignocellulosic agricultural waste & renewable electricity-powered microwaves, targeting over 70% reduction in Scope 3 emissions. Successful pilot tests at Metso Outotec's Frankfurt facility validated feasibility, throughout independent firm Hatch confirming greenhouse gas reduction potential. Rio Tinto advances toward continuous pilot plant construction processing one metric ton hourly, establishing sustainability criteria excluding old-growth forests & ensuring responsible biomass sourcing.