BHP Billiton raised its wages offer to workers at the world's largest copper mine as it attempts to resolve a strike that will enter its 15th day.

It is offering more pay and higher bonuses, BHP Billiton spokeswoman Alejandra Wood said in an e-mailed statement from Santiago.

Workers are meeting now at an athletic centre at the mine to discuss the progress of talks with management, said Luis Troncoso, president of the Escondida's Workers Union No. 1, in a phone interview before BHP's announcement.

Prices of copper, used in wires and pipes, have more than doubled in the past year as consumption soared in China, prompting unions to seek a greater share of the industry's record profits. Mine management said Aug. 16 the dispute was costing owners including BHP Billiton, Rio Tinto Group and Mitsubishi Corp.