News reports have laid the blame for the attack on terrorist group the Revolutionary Armed Forces of Colombia, known as FARC.

At the time of publication, Cerrejon had not placed blame on any specific group for the bombing which occurred early on Thursday.

“Around 4.45am (local time), the train, which headed towards the coal port of Puerto Bolivar, was attacked with explosives ... which produced the derailment of 17 wagons,” Cerrejon officials told Reuters.

The company’s export business was back in operation earlier this week following a month-long strike that stopped both exports and the attending government royalties.

Cerrejon has since signed a wage deal to end the stoppage.

Security forces are pointing fingers at FARC which is usually at the center of such acts.

Rebels and the government are working to reach a peace deal in talks in Cuba, Reuters said.

The Sintracarbon union also called for answers.

“We call on the authorities ... to redouble efforts to ensure our safety and that of the company," it said.

It is the second explosive attack in as many months for Cerrejon. Assailants blasted four work trucks at the company’s Mina Sur complex in the Guajira province in February.

The company is a joint venture between Anglo American, BHP Billiton and Xstrata. It produced 34.3 million metric tons last year and is investing $US1.3 billion to ramp up to 40 million tons per annum by 2015.

Colombia is the world’s fourth-largest coal exporter, and Cerrejon is one of the Andean nation’s major players.