BHP declared on Tuesday that delivery from its copper mines in Chile had come to a halt due to a walkout staged by over 2,000 union workers.

The world’s largest mining company based in Australia, had declared a ‘force majeure’ in regard to the work stoppage. Force majeure is a form of legal protection used by mining producers to justify a delay in shipment to customers due to natural disasters or strikes. The halt in operation had cut output by 60 percent.

“We will certainly be looking at that as an option, but nothing has been decided yet,” BHP spokeswoman Emma Meade told The Australian yesterday.

The option includes bringing in strike workers to return the operation back to normal. Copper rose to $7930 a tonne on the London Metal exchange, an increase of 0.9 percent as speculators considered whether the strike would disrupt copper production. BHP Billiton spokesman Mauro Valdes said in Santiago that output would depend on the copper content of ore being processed.

The halt in production came about after the firm refuse to meet a union demand of a 17 percent increase in pay, a union spokesman said. Copper prices doubled a year ago and the union seek a share in the profit. A union wage negotiation is also taking place with Codelco, the world’s largest copper company.

Valdes said the strike's impact on production would depend on the copper content of ore