Although the union striking at the world's largest copper mine lowered its wage and bonus demands, mine operator BHP Billiton said it won't budge from its last offer which was overwhelmingly rejected by the striking miners Sunday.

As of Tuesday, the union and the Escondida Mine management in Chile had not scheduled a new round of talks to try to resolve the 15-day old strike.

Reuters reported that union President Luis Troncoso told a news conference that the union had reduced its raise demand from 10% to 8% and lowered its special bonus request from $30,000 to $19,000 per miner. Troncoso said the union will file litigation against Escondida management for anti-union practices.

Under Chilean law, individual workers can negotiate their own deal with the company and return to work after two weeks. On Monday, Escondida posted an announcement on its web site offering employment to individual mine workers. However, union leaders said their 2,052 members will not break ranks.

The Financial Times reported Wednesday that BHP Billiton may have to consider flying Peruvian workers to Escondida to restore production at the mine. Chilean regulations allow bringing in outside workers after 15 days of a strike action.

Escondida produces 8% of the world's mined copper supply and 20% of Chile's copper production. The labor dispute is considered a benchmark for upcoming labour negotiations for state-owned Codelco Copper of Chile, the world's largest copper producer. The Chilean Labour Ministry participated in the latest round of negotiations when striking workers overwhelming rejected a new offer.

BHP Billiton Ltd., the world's largest diversified mining company, said Wednesday that full-year profit rose a record 63% due to higher copper and iron ore prices. The company will spend $3 billion buying back shares.