SANTIAGO – Leaders of three Chilean unions demonstrated on Friday to express support for striking workers at the massive La Escondida copper mine.

Members of the CTT union, the Workers’ Alternative and the CIUS union gathered outside the offices of BHP Billiton, which has a 57.5 percent stake in Minera Escondida, the company that operates the open-pit mine.

A total of 2,500 workers are now facing off against the world’s largest mining company, CIUS member Guillermo Solis told EFE, saying the demonstration was aimed at showing the unions’ solidarity.

The demonstrators said BHP Billiton had the resources to wait out the striking employees and accused it of inventing a copper crisis to reduce its labor expenses.

Copper prices have fallen sharply since the last collective bargaining agreement was reached four years ago.

The strike began on Feb. 8 after a breakdown in talks aimed at hammering out a new CBA.

The Escondida No. 1 union is demanding a 7 percent salary hike, while the company has refused to raise wages and is proposing a reduction in some benefits.

London-based mining giant Rio Tinto and Japan’s Jeco Corporation have minority stakes in northern Chile’s La Escondida, the world’s largest copper mine with average output of roughly 100,000 tons of the red metal per month.