* Mine unions demanding 50 pct pay rise
* Mine firms not ready to give over 12 pct hike
LUSAKA Nov 26 (Reuters) - Mine unions in Zambia are demanding a 50 percent pay rise, far above the 12 percent increase offered by companies, which could lead to labour unrest in Africa's top copper producer, a source close to the negotiations said on Monday.
Zambia's largest mining union, the Mine Workers Union of Zambia, confirmed it was in talks with Glencore's Mopani Copper Mines, Vedanta's Konkola Copper Mines and Jinchuan's Chibuluma mine over 2013 pay increases, but declined to comment on the figures.
"These talks are likely to be difficult and labour unrest cannot be ruled out. The mines are trying to keep their costs low and the unions and trying to get the best for the miners," the source said.
Zambia's Industrial Relations Court in September awarded workers at First Quantum Minerals a 13 percent increase this year and 12 percent in 2013 following a pay dispute.
"The mining companies are saying they cannot pay more than the court ordered (First Quantum's) Kansanshi mine to pay its workers in 2013," the source added.
Mines and the unions in Africa's top copper producer opened talks for 2013 pay in October and the negotiations are expected to be concluded by the end of December.
South Africa's gold and platinum mining industries have been battered this year by months of wildcat strikes and often deadly labour unrest that has led to the deaths of more than 50 people.