So far, 2013 has been a turbulent year for Colombian coal production, with a month-long strike at Cerrejon in February and the ongoing strike at Drummond both hitting output levels.

Cerrejon, a joint venture between Anglo American, BHP Billiton and Glencore Xstrata, is the country’s largest producer. It turned out 34.3 million tons last year and is investing $1.3 billion to ramp up to 40 million tons per annum by 2015.

According to the national mining agency, US-owned Drummond’s mines produced about 26 million tons of coal in 2012, so due to the strike, the country is losing about one-third of its daily output.

As well as strikes, rail closures and a shipping halt issued to Drummond for an environmental incident also reduced output.

Colombia, the world’s number four coal exporter, cut its forecast for 2013 to 94 million tons earlier this year, down from a previous 97Mt.

Its production figures have taken a downward turn over the past few years.

Colombian President Juan Manuel Santos, who came to power in 2010, estimated 2013 output of 100Mt and 114Mt next year.

Coal is Colombia’s second largest export commodity after oil.