SANTIAGO, Aug 02, 2011 (Dow Jones Commodities News via Comtex) -- The labor strike at Chilean copper mine Escondida entered its 12th day Tuesday while the union awaits a fresh offer from the company, a union leader said.

Escondida, the world's largest copper mine, accounting for 7% of global annual output, is losing around 3,000 metric tons of the industrial metal a day on the stoppage.

The 2,375-strong union recently eased its demands, eliminating a housing benefit requisite and cutting by 20% the bonus it's seeking.

Last week, the mining company, operated and controlled by BHP Billiton Ltd. (BHP, BHP.AU) presented workers with a new bonus offer to end the strike, but union members voted by a landslide to reject the offer.

Escondida officials didn't respond to calls for comment, but a spokesperson last week told reporters the company was prepared to withstand a long labor conflict.

The company recently invoked the force majeure clause for its copper concentrate shipments, freeing it from its contract obligations due to unforeseen and uncontrollable events.

BHP has a 57.5% stake in Escondida, while Rio Tinto PLC (RIO, RIO.LN) holds 30%. The remaining 12.5% is held by a Japanese consortium led by Mitsubishi Corp. (MSBHY, 8058.TO).

The open-pit mine located in northern Chile produces around 1.1 million metric tons of copper a year in the form of concentrates and cathodes, which are large sheets of 99.99% pure copper.