(Reuters) - Workers at the Zambian unit of Canada's First Quantum Minerals went on strike on Tuesday for a 100 percent pay rise, bringing production to a halt at the country's largest copper mine, a company official said.

It came as a surprise because we are in the middle of negotiations with the union. We are not producing copper because all the workers have gone on strike, Kansanshi mine spokesman Godfrey Msiska told Reuters.

Msiska said the management at the mine, which produced 231,000 tonnes of copper in 2010, was meeting union officials to try and resolve the problem.