Peru's national federation of mining unions has started a two-day nationwide strike to pressure the government to change rules on labor benefits, although unions at several key mines had said they would not participate in the walkout.
The strike is underway, Luis Castillo, director of the mining federation, told Reuters on Monday.
It is for better benefits, on retirement ages and profit-sharing, which we've been demanding for three years and so far we have got nothing.
He said it would take several hours to know how many workers had gone on strike in the Andean country, a leading global minerals exporter.
The federation is upset that President Alan Garcia rejected a law, initially passed by Congress, to lower the age for retirement. Workers also want Congress to throw out a rule that limits the amount they can earn from profits that are distributed to them by companies.
The last time miners across Peru downed tools was in mid-2008 and the strike helped push copper prices toward a record high.
Globally, Peru ranks No. 1 in silver output, No. 2 in zinc, No. 3 in copper and tin, No. 4 in lead and No. 6 in gold.
The walkout would be held as minerals prices have gained ground since crashing in late 2008, and mining companies are expected to see higher third-quarter profits after a tough first half of this year.
The strike was expected to be supported by unions at Volcan (VOL_pb.LM), one of Peru's top zinc and silver producers, and at the Yanacocha gold mine of Newmont Mining (NEM.N), union officials said.
Unions at Freeport-McMoRan's (FCX.N) Cerro Verde mine, one of Peru's main copper pits, were also expected to strike.
Workers at the key mines and smelter of Southern Copper (SPC.LM) (PCU.N) and BHP Billiton's (BHP.AX)(BLT.L) Antamina mine were expected to stay on the job, union officials had said.