Copper prices have spiked in recent weeks over fears of a strike...

Copper prices have spiked in recent weeks over fears of a strike at Escondida, which produced 6 percent of the world's supply in 2015. One tonne of copper was trading at $5,795.00 at 7:18 p.m. local time (1018 GMT), up from a morning low of $5,786.

BHP Billiton said it planned to halt production during the strike since it could not guarantee the safety of the 80 workers the government had authorized to remain at the mine to perform "critical duties", such as equipment upkeep and adherence to environmental protocols.

http://www.reuters.com/article/us-chile-copper-escondida-idUSKBN15M2MA