Nov 4 (Bloomberg) -- Unions representing workers at the Collahuasi copper mine, the world’s fourth largest, agreed to return to the negotiating table tomorrow after suspending government-mediated wage talks today.

Talks will restart tomorrow, Manuel Munoz, a union leader, said as he left the negotiating room in the northern Chilean city of Iquique. He declined to elaborate.

Earlier today union representatives broke off talks with the mining company, owned by Anglo American Plc and Xstrata Plc, and vowed to start a strike on Nov. 5. A stoppage at Collahuasi in Chile’s Atacama Desert would drive up copper prices, Mark Pervan, an analyst at ANZ Bank Ltd. said in a report today.

"They realized they broke off mediated talks and they repented,” Bernardita Fernandez, a spokeswoman for Collahuasi, said in an interview. "They asked for a meeting tomorrow at 11 a.m. We are available all day until midnight when the deadline for mediated talks expires.”

The two sides entered into negotiations mediated by Chile’s Work Inspectorate after failing to reach an agreement ahead of an Oct. 30 deadline. Collahuasi’s workers rejected a company offer on Oct. 27 that included a bonus of 8.9 million pesos ($18,262).

Workers at BHP Billiton Ltd.’s Escondida copper mine were paid bonuses of more than 14 million pesos to sign a new wage deal last year.

Collahuasi produced 535,000 metric tons of copper last year, or 3.5 percent of the world’s output, according to Standard Bank Plc.

Anglo American and Xstrata each own 44 percent and a group led by Mitsui & Co. holds the rest.

Supply-Challenged

"Confirmation that a strike will occur will be supportive for copper price,” Peter Richardson, chief metals economist for Morgan Stanley Australia Ltd., said by telephone from Melbourne. "Copper is a supply-challenged industry.”

Copper prices fell for the first time in three days. Copper futures for December delivery lost 5.4 cents, or 1.4 percent, to close at $3.785 a pound at 1:26 p.m. on the Comex in New York.

The Collahuasi mine located near Chile’s border with Bolivia in the Andes Mountains is unrelated to the San Jose copper and gold mine where the rescue of 33 miners was watched by millions of people across the world last month.