Dhaka, July 31 -- US President Donald Trump on Wednesday imposed a pared-back import tariff on copper that excluded the metal in its raw form from a 50-percent levy on semi-finished products.

The price of copper, which had soared after Trump flagged the tariffs earlier this month, plunged by almost 20 percent when it emerged the duty would not apply to refined or raw copper metal.

The metal is used extensively in industry and defense manufacturing, and the White House said the United States had become overly reliant on copper imports, having once been a world leader in production.

It is also critical for the artificial intelligence and green energy revolutions.

The tariffs will take effect Friday, the White House said.

Chile, the wor...