US copper jumps 12pc as Trump plans tariff on imported copper

A worker transfers newly made copper slugs, to be pressed into bullets, at Barnes Bullets in Mona, Utah, in this January 6, 2016 file photo. Traders have been raising their bets on an even steeper decline in copper prices in the coming months, worried that Chinese demand is dwindling just as investment made when markets were booming unleashes a new wave of supply. REUTERS/George Frey/Files