Chilean copper miners at state-owned Codelco began a 24-hour work stoppage early Tuesday to demand greater job security, according to unions Tuesday.
The protests also delayed operations at BHP Billiton's Escondida project, the world's largest copper mine, and blocked the access road to Anglo American's Los Bronces mine, Reuters reported.
Antofagasta's Chile operations were also in the firing line.
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Copper for delivery in three months advanced 0.3% to $7,515.50 a metric ton at 13:05 Tuesday.
Matt Basi, an analyst at CMC Markets, said the strike seems to have "panicked some investors out of positions, perhaps wary of the potential for a short squeeze".
Shares in BHP, Anglo American and Antofagasta advanced in afternoon trading, in line with the broader mining sector as data showed that Chinese inflation had slowed in March.
This has increased hopes that the People's Bank of China will hold off from tightening policy for the time being.
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