A national strike by mine workers in Peru has spread to half the industry’s unions, threatening to disrupt global supplies of metals such as copper, zinc and gold after 4 days of lengthy negotiations between the federation and the labor ministry to avert the strike failed on Sunday.

The walkout began at midnight local time. Workers at 33 unions of 70 mining unions joined the strike, including employees of Southern Copper Corp, Doe Run Resources Corp and Pan American Silver Corp. The miners' federation claimed that as many as 40,000 members had joined the strike out of about 110,000 miners estimated to be work in the mining sector overall. The National Federation of Mining, Metallurgy and Steel Workers, which represents some 22,000 miner said that the strike is indefinite.

Mr Jorge del Castillo prime minister of Peru described the strike as a complete flop. Peru’s labor ministry in a statement said "In the coming hours, the strike will be declared illegal and any worker who has been absent from work for three straight days after that may be fired by his employer." It is not immediately clear if the union could appeal the measure and continue with the protest.

The majority of Peru's mines are controlled by large multinational companies, whose profits have surged on high metals prices. Miners are seeking a greater share of profits and better pensions as surging metal prices generate record earnings for producers.

The last nationwide strike took place three years ago, when miners stopped work for 48 hours to protest the previous government's labor policies.

Peru is the world’s largest producer of silver, the 3rd largest in zinc, copper and tin and ranks 5th in gold. Mining is Peru's main economic drivers and accounts for more than half of export earnings. According to the Web site of Peru's Energy and Mines Ministry, Peru produced 1.05 million tonnes of copper, 203,269 kilograms of gold, 1.13 million tonnes of zinc and 1.3 million kilograms of silver in 2006.