Workers have gone on indefinite strikes at Chile and Peru’s largest copper mines and ignited the potential for further struggles in the sector.

The neighbouring South American countries are the world’s first- and second- biggest producers of copper, respectively. Mining companies there have benefitted over the past few years from rising global demand and prices, but workers have seen little to no benefit from the boom.

Now mine workers are flexing their muscle to demand their share of the spoils.

Explaining why his union’s 1300 members had walked off the job the day before, Zenon Mujica, the secretary general of the union at Peru’s Cerro Verde mine, said on March 11: "Copper prices have improved, production has improved, but wages for workers haven't improved"

Cerro Verde, which is owned by US mining company Freeport-McMoran, saw output almost double last year due to the introduction of new technology.

The company has attempted to circumvent the strike by hiring contract workers. The government is expected to declare the strike illegal within the next week, meaning workers face the prospect of being sacked if they do not return to work.

However, Mujica said the union is preparing to expand the workers’ struggle into a “social conflict” and involve local communities and organisations to ensure the workers’ voices are heard.

The strike at Cerro Verde has further shaken a global copper market feeling the effects of a strike that began on February 9 at the Escondida copper mine in Chile.

Escondida is the largest copper mine in the world and represents about 5% of global production.

The strike by Escondida’s 2500 workers has so far cost BHP Billiton and its mine partners (including Rio Tinto and Mitsubishi) more than US$712 million in lost sales.

A key point of contention in negotiations is BHP’s attempts to give new workers fewer benefits than those already employed at the mine.

This has been seen as an attempt to circumvent a provision in the new labour law, set to come into effect in April, which will prevent companies from offering weaker benefits during negotiations than those afforded in previous contracts.

If BHP is successful, the door will be open to lowering the floor for negotiations at the next round of talks. This would also wind back gains won over years of struggle, including through previous strikes at Escondida in 2006 and 2011.

Conversely, there are fears that the strike could encourage others to follow suit, with the owners of a number of other copper mines in Chile – that together represent 12% of global output - set to renegotiate contracts with workers later this year.

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