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.

United States President Donald Trump has said he will announce a 50 percent tariff on copper, hoping to boost domestic production of a metal critical to electric vehicles, military hardware, the power grid and many consumer goods.