The Dow Jones newswire reported that in a filing to the local SVS securities regulator, Escondida called the workers’ strike illegal and noted the walkout was “producing an impact on the production of copper concentrates”

Union spokesman Marcelo Tapia reportedly told the newswire production at the mine had completely stopped and access to the port had been blocked.

The mine’s sole union, comprising 2375 members, went on strike last week to protest what it claims are unmet contract terms.

BHP called the strike illegal and declined an invitation earlier this week to assist a government-mediation round of negotiations.

BHP holds a 57.5% stake in the mine, with Rio Tinto holding 30% and a Japanese consortium led by Mitsubishi holding the balance.

Shares in BHP were down 1.51%, or A65c, in morning trade to $42.35.