Workers at U.S. coal company Drummond's Pribbenow mine located in northern Colombia have gone on strike after a breakdown in contract talks, a union official said on Thursday.

The open-pit mine produces about 2 million tonnes of coal per month, according to privately owned Drummond, which confirmed that operations have been shut down by the work stoppage.

"The mine is paralyzed," said Joaquin Romero, president of the Funtraenergetica labor organization which represents Pribbenow's 3,500 workers.

"We hope to restart talks in the days to come," Romero said.

The union is negotiating a two-year contract. Talks have bogged down over miners' demands for higher pay and better employment security, according to Romero, who said 100 workers were fired from the mine last year.

Drummond is a family-run business based in Birmingham, Alabama, headed by Garry Neil Drummond.

The price of Colombian coal at the Bolivar export terminal CO-FOBPBL-CO has more than tripled since the start of 2007, rising $123.80 to $174.50 a tonne, boosted by strong demand growth for coal in China and other emerging markets.