President Donald Trump mentioned Tuesday — almost in passing — that he planned to impose a 50% tariff on copper imports. It still hit like a bombshell, with potential to shake up U.S. efforts to expand,

Chile, the world's No. 1 copper producer, is in wait-and-see mode after U.S. President Donald Trump announced a surprise 50% tariff on imports of the red metal, with the Andean nation blindsided while its top miner held out hope of exemptions.

Copper futures rose dramatically following President Trump's plan for a 50% import tariff, pushing domestic prices to a 25% premium over global markets amid growing demand.