Workers at BHP Billiton Group's Escondida copper mine in Chile rejected a wage offer and voted for a strike, Reuters reported Jan. 31, citing the union.

The company will likely ask for government mediation to resolve the matter, which would delay the strike by a week.

The union members previously asked the 2,500 union members to reject the company's offer of a US$12,000 bonus, calling the offer "absurd."

The workers had set up a fund of 250 million Chilean pesos in mid-January to finance the potential strike.

The last wage negotiations occurred four years ago when copper prices were significantly higher, and each worker ended up with a US$49,000 bonus.

Others shareholders in Escondida include Rio Tinto and Mitsubishi Corp.