Thousands of tonnes of coal from Colombian mines owned by companies Drummond and Glencore is being stopped from getting to port due to a railway workers' strike, Reuters cited a union leader as telling it today. Some 600 employees of the Fenoco transportation firm have called a work stoppage to demand recognition of their labor union. The strike has stopped 130,000 tonnes of coal per day from being transported to Caribbean ports from northern Colombian mines, union chief Felix Herrera said. "When Fenoco comes around to recognizing the union and is willing to sit down and negotiate with us, we will lift the strike," Herrera said. "Coal is not leaving any of the mines owned by Drummond or Glencore." "Coal transportation operations, by train, are paralyzed due to the strike," a spokesperson for privately held, U.S.-based Drummond told Reuters. Representatives of Swiss-based commodities firm Glencore could not be immediately reached. Glencore and Drummond are two of Colombia's biggest coal producers.