By David Hodari 

LONDON--Copper prices climbed Thursday, buoyed by a fresh wave of trade optimism after a mixed performance so far this week.

The industrial metal was up 1.24% at $6,225.50 a metric ton, while zinc and nickel climbed by similar percentages.

Gold, meanwhile, ticked down 0.1% to $1,244.46 a troy ounce as the U.S. dollar held its mild gains of the past few days.

The dollar and gold tend to move in opposite directions, and the WSJ Dollar Index was last flat, having climbed 0.3% over the past five days.

Gains for base metals--London copper futures climbed to their highest in a week--came as trade jitters eased on news that Chinese companies had moved to resume purchases of U.S. soybeans.

To some analysts, those developments represented China keeping up its end of a bargain struck two weeks ago at the Group of 20 summit to ease tensions with the U.S. after months of hostile rhetoric and waves of tariffs.

"The move in metals is a macro-driven one, with a sense in the market that collaboration between the U.S. and China is going to increase again, " said Hunter Hillcoat, mining analyst at Investec Securities. "One interpretation is that the trade war fears that have been included in prices are being relieved."

Fresh supply fears were also boosting copper, according to SP Angel analyst John Meyer, with reports of 700 workers having taken over Chilean state-owned Codelco's copper mine at Chuquicamata. The mine is Codelco's third largest operation and contributed 200,000 tons to global supply in the first three quarters of the year.

Market participants have been surprised by a relative lack of labor disputes so far in 2018, and easy access to copper has combined with fears of a slowdown in Chinese economic growth--and an attendant slowing in copper demand--to weigh on copper futures.

Investors were watching out for U.S. inflation figures, due Thursday, and Chinese credit data, expected Friday.

Among precious metals, silver was up 0.07% at $14.75 a troy ounce, palladium was up 0.2% at $1,268.50 a troy ounce and platinum was down 0.29% at $800.90 a troy ounce.

Among base metals, aluminum was down 0.1% at $1,934.50 a metric ton, zinc was up 1.09% at $2,594 a metric ton, tin was up 0.34% at $19,410 a metric ton, nickel was up 1.25% at $10,920 a metric ton and lead was up 0.2% at $1,970.50 a metric ton.

Write to David Hodari at David.Hodari@wsj.com

(END) Dow Jones Newswires

December 13, 2018 06:40 ET (11:40 GMT)