Mining titan Rio Tinto (ASX:RIO) has initiated legal proceedings against the United States government, seeking a refund of millions in tariffs following a landmark Supreme Court ruling.
The lawsuit, filed in the US Court of International Trade, comes at a delicate moment for the Anglo-Australian firm as it simultaneously navigates the complex political landscape to secure the future of its massive Resolution Copper Project in Arizona.
The litigation follows a February decision by the Supreme Court which invalidated President Donald Trump’s "liberation day" tariffs, ruling that the administration exceeded its authority under the International Emergency Economic Powers Act of 1977.
While Rio Tinto’s recent "taxes paid" report disclosed nearly US$1 billion in total tariff payments for 2025, this specific legal action is believed to target an initial recovery of approximately US$10 million.
The claim excludes valid duties applied to Canadian aluminium under Section 232 of the Trade Expansion Act.
The timing of the filing is notable, occurring just days after federal officials formalised a long-awaited land swap essential for the Resolution Copper venture.
The project, a joint venture with BHP(ASX:BHP), has faced a decade of intense opposition from First Nations communities regarding the sacred Oak Flat site.
Despite these tensions, Rio Tinto is also re-evaluating its Washington ties, flagging a potential exit from the National Mining Association due to fundamental disagreements over climate policy and the 2015 Paris Agreement, even as it seeks "critical metal" subsidies from the current administration.