Copper production at Chilean copper mine Dona Ines de Collahuasi has been cut into, as a labor strike at the mine rolls into its second day, the company said Tuesday.

Collahuasi, one of the globe's biggest copper mines, is no stranger to labor disruptions, after facing a one-day strike earlier this year and in 2010 a 33-day work stoppage, the longest strike at a privately held mine in Chile.

The strike has halted copper concentrate production, and partially stopped copper cathode output, Collahuasi said.

Cathodes are large sheets of 99.99% pure copper, while concentrates must be smelted to get the purer form of the industrial metal.

Roughly 92% of the Collahuasi's output is in the concentrate form and 8% is cathodes. The mine also produces small amounts of molybdenum, a metal used to harden steel.

The mine's Patache port, which was shut down for several months in 2010 after an accident following the 33-day strike, is operating normally.

According to the company, 10% of its workers went on strike Monday. Collahuasi has implemented a contingency plan to safeguard its staff, contract workers and installations.

The mining company has called the strike illegal as workers aren't currently negotiating new contracts. Local labor laws allow for labor stoppages but only during the collective-bargaining process.

Collahuasi, the world's third-largest copper mine with an annual production of around 500,000 metric tons of copper, is located at over 4,000 meters above sea level high in the Andes of northern Chile.

Global diversified mining companies Xstrata PLC (XTA.LN) and Anglo American PLC (AAUKY, AAL.LN) each hold a 44% stake in the mine, while a consortium led by Mitsui & Co. (MITSY, 8031.TO) holds the remaining 12%.

-By Anthony Esposito and Carolina Pica, Dow Jones Newswires; 56-2-715-8919; chile@dowjones.com