Mining company BHP Billiton says it wants to expand production at its Escondida copper mine in northern Chile even as a strike enters its fourth week.

The Anglo-Australian firm says that in the coming days it hopes to add to the 50 replacement workers it has already hired since the strike began. Production at the mine has been at about 50 percent of normal since more than 2,000 miners walked out August 7.

The hiring of replacements has attracted scorn from the union, which has sought higher pay and benefits for its members. But negotiations between the union and the mine company have been at a standstill since the union rejected the latest offer more than a week ago.

Escondida is Chile's largest copper mine, and accounts for eight percent of world copper production.

Some information for this report was provided by Reuters.