NEW YORK (AP) – Copper prices fell slightly Thursday, retreating after hitting a record on supply concerns fed by a labor strike in Chile, the world’s largest producer.

Other commodities traded mostly lower, with crude oil falling back from a new record above $115 and gold and silver also declining.

Contract workers at Chile’s state-owned copper giant Codelco went on strike Wednesday, alleging the company reneged on an agreement that ended a monthlong strike last year. The stoppage, which continued Thursday, has halted operations at two of Codelco’s five mines – the Andina and El Salvador. Codelco said the protests posed a threat to other workers who didn’t join the strike.

“The supply of copper concentrates is very tight so a strike at a mine as opposed to a smelter is much more of a concern,” said Catherine Virga, base metals analyst at CPM Group in New York.

Copper for May delivery jumped to a contract high of $4.0495 a pound on the New York Mercantile Exchange before pulling back on profit-taking to settle at $3.913, down 4.25 cents.

Meanwhile, lower energy prices and a stronger dollar gave investors reasons to push gold prices down Thursday, reversing a three-day rally. Investors had been turning to gold as a safe haven from inflation, driven by record-high energy prices and a declining dollar.

Despite the decline, experts predict could climb higher. In a report released Thursday, the World Gold Council said demand for gold as a safe-haven asset is likely to remain strong if U.S. economic troubles deepen.

Gold for June delivery fell $5.40 to settle at $942.90 an ounce on the Nymex, after earlier falling as low as $941.60. Gold prices closed at $948.30 on Wednesday, its highest level in three weeks.

Silver for May delivery lost 2 cents to settle at $18.305 an ounce on the Nymex.

In energy prices, crude oil fell slightly after cruising to another record in overnight trading on concerns about falling supplies and rising global demand.

Light, sweet crude for May delivery fell 7 cents to settle at $114.86 a barrel on the Nymex, after earlier rising to $115.54, a new trading record. It was the contract’s first lower close in a week.

Other energy futures traded mixed Thursday. May gasoline futures rose 1.88 cents to settle at a record $2.9578 a gallon after earlier rising to a trading record of $2.9749 a gallon. May heating oil futures fell 1.56 cents to settle at $3.2674 a gallon.

In agriculture, wheat futures fell sharply as supply concerns eased two days after Kazakhstan said it would ban exports to control rising domestic food inflation.

Wheat for May delivery fell 11.5 cents to settle at $9.13 a bushel on the Chicago Board of Trade.

Other agriculture futures also traded mixed. Soybeans for May delivery added 5.75 cents to settle at $13.505 on the CBOT, while May corn futures traded flat at $6.035 a bushel.

AP-ES-04-17-08 1714EDT