Mining giant Rio Tinto faced gross costs of approximately $300m (£223.84m) due to US tariffs on its primary aluminium exports from Canada during the first half of 2025 (H1 2025).

Rio Tinto's shipments to the US in H1, amounting to approximately 723,000 tonnes (t), represent nearly three-quarters of its Canadian output.

The tariffs, introduced by President Trump to boost domestic production, have disrupted global metals supply chains.

Initially set at 25% in March, the tariffs were increased to 50% in June, with a proposed 50% tariff on copper causing market upheaval.

A significant portion of the costs incurred by Rio Tinto were offset by the corresponding rise in the US Midwest duty-paid premium, which quickly adjusted to the initial 25% tariff level in the first quarter (Q1).

However, by the end of Q2, it had not fully compensated for the increased 50% tariff rate.

US aluminium price futures indicate rising costs for US buyers and industry executives have expressed concerns about the potential suppression of US demand, according to a report by Bloomberg.

Rio Tinto said in a statement: “The impact of tariffs is still feeding through to inflation and sentiment.”

Alcoa, the largest US aluminium producer, has also felt the sting, with Q2 costs reaching $115m.

The company has redirected Canadian aluminium to international customers to avoid tariff-related expenses.

Alcoa is also in discussions with administrations, governments and policymakers, primarily in the US and Canada, related to the impacts of tariffs.

For Q3 2025, Alcoa’s aluminium segment is predicting a sequential negative impact of around $90m as a result of US tariffs on aluminium imports from Canada.

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