However, on Monday, investors were watching possible supply problems that boosted prices around the same time last year, with BHP Billiton resuming contract negotiations with workers at its Chilean Escondida operation. In 2017, a 44-day strike at the copper mine, the world’s largest, provided support to prices.

“Given the aggressive stance of the unions from the start of these talks, their bonus claims would break records for the Chilean industry,” said Hunter Hillcoat, an analyst at Investec. That may prompt investors “to gather up additional inventory while they still can,” Mr. Hillcoat said.

Traders were waiting to see whether copper could sustain its Monday rally, as the metal has gotten off to a lukewarm start to the year after hitting a nearly four-year high late in December.

“The metal has struggled to break higher on every attempt in the last few months,” said Dee Perera, from the London Metal Exchange desk at Marex Spectron, in a note.

Analysts were also tracking the latest news on trade policies, with some worried that protectionism will slow global trade and eventually hurt the global economy and commodity demand.

Among precious metals, front-month gold for June delivery swung between small gains and losses and closed down 0.1% at $1,293.10 a troy ounce. Some analysts expect muted price moves leading up to next week’s Federal Reserve meeting with the central bank expected to raise interest rates. Gold struggles to compete with yield-bearing assets like Treasurys as borrowing costs rise.

Courtesy : www.wsj.com