BHP's Spence copper mine in Chile hit by fresh strike

Workers at BHP Billiton's (ASX, NYSE: BHP) Spence copper mine in northern Chile, the world's largest producer of the metal, have begun a 24-hour strike, a union representative said Monday, citing slow progress in labour talks.

Strike comes on the heels of BHP’s recent announcement that it's studying a $2.2 billion investment to expand the operation.

The action follows two other one-day protests at the mine on May 13 and May 3, in which the union also cited minimal headway in ongoing negotiations, Reuters reports.

In April, the company laid off about 7% of its 1,060 Spence workers, following a trend among copper mines in Chile who have been squeezed by low prices and weak demand in key consumer China.

The strikes come on the heels of BHP’s recent announcement that it is studying a $2.2 billion investment to expand the operation, which would extend the mine life by about 50 years.

Spence produced 175,600 tonnes of copper last year.