Akhir 20, 1432 H/ March 25, 2011, SPA -- More than 600 workers at Zambia's Chinese-owned Chambishi Copper Smelter have downed tools demanding a pay rise, bringing production at the plant to a halt, a union official said on Friday, according to Reuters. Chambishi, a joint venture of China Nonferrous Metals Corporation (CNMC) and Yunnan Copper Industry about 370 km north of Lusaka, processes 150,000 tonnes of blister copper per annum. Mundia Sikufele, president of the National Union of Mining and Allied Workers, said the strike started on Thursday after the management offered a 12 percent pay rise, which the workers rejected. "There is no production because the workers did not enter the plant yesterday and even today they are outside demanding for a higher offer," Sikufele said. Sikufele could not say how much the workers are demanding. "The management has indicated readiness to renegotiate on condition that the workers call off the strike immediately," Sikufele said. First Quantum Minerals' Kansanshi mine and Chibuluma mine, owned by South Africa's Metorex, last year joined Equinox Minerals' Lumwana mine in using Chambishi for processing copper concentrates. The Chambishi smelter is located in an economic zone, where Zambian authorities are waiving taxes to attract investments and encourage value addition to raw copper.