U.S. copper prices are trading at records ahead of the 50% tariff that the president has promised to impose on imports.

Ivanhoe Mines founder Robert Friedland said the tariffs would cut America’s dependence on imported critical minerals at a time when self-sufficiency was crucial.

Some US mining stocks are making gains on Tuesday after US President Donald Trump said he was expecting to place a 50% tariff on Copper imports. The July delivery COMEX Copper contract surged 13.2% to close at 5.645/lb, the highest price on record going back to 1968.