Prices of copper in the US have surged since January, when President Donald Trump threatened to impose a tariff on imports of the metal that’s a vital component in power networks, plumbing and industrial machinery.

Copper is used in a wide variety of products from electronics, wiring, machinery and cars. The U.S. produces a majority of the copper it uses but still imports large quantities, primarily from

The president was following through on an earlier statement that he would target a key metal used for semiconductors, lithium-ion batteries and more.