Mitsubishi Materials and Mitsui & Co. will join U.S.-Japan projects to develop rare earths, lithium, and copper, according to Nikkei.
Prime Minister Sanae Takaichi and President Donald Trump are expected to formalize the deal at their March 19 summit in Washington, building on an October 2025 framework.
The leaders also plan to finalize a broader G-7 critical minerals action plan that could impose tariffs on Chinese mineral imports, per Mainichi.