Unionized workers at Chilean copper mine Escondida, controlled and operated by BHP Billiton Ltd. (BHP), accepted an early wage and benefits package, ahead of their Dec. 5 contract expiration date.

The move eliminates the possibility of a strike such as the one that shut down the copper mine, the world's largest, for nearly a month in 2006.

"This is historical; it happened without any conflict whatsoever," said Pedro Marin, the head of the Federation of Mining Workers and a former Escondida union leader.

The 2,250-strong Escondida union belongs to the federation Marin heads.

In a vote held over the weekend, about 72% of unionized workers accepted the unusually long 44-month contract offer, which included a 5.5% wage increase, bonuses totalling about $25,000, a $6,300 interest-free loan, and various social benefits including an early retirement plan.

BHP representatives didn't immediately respond to calls seeking comment on the offer, but a spokesman for the company last week called the offer "mutually beneficial."

BHP has a 57.5% stake in Escondida. Anglo-Australian mining company Rio Tinto PLC (RTP) holds 30%, with an additional 10% held by a Japanese consortium led by Mitsubishi Corp. (8058.TO) and the remaining 2.5% by International Finance Corp. (IFC.KW), the private-sector unit of the World Bank.

-By Carolina Pica, Dow Jones Newswires; 56-2-820-4244; carolina.pica@dowjones.com