Miners at Codelco’s Chilean Chuquicamata copper mine have commenced a strike after rejecting the company’s new 36-month contract, which includes an increased wage rise.

Codelco’s offer involved a $23,000 end-of-negotiation bonus, a 3.8% increase in wages, access to $6,000 low interest rate loans and other benefits.

The workers, who have requested a 4.3% rise in wages and larger bonuses, said Codelco’s proposal was not as generous when compared to the contract finalised at the BHP Billiton-owned La Escondida mine in Chile.

In October 2009 La Escondida miners signed a contract that included a 5% pay hike, a $25,340 end-of-negotiation bonus and $6,339 worth of soft loans.

The indefinite strike is likely to lead to a steep rise in copper prices, which increased by 140% in 2009.