The attack was carried out by the Revolutionary Armed Forces of Colombia (FARC), the Andean nation’s leading Marxist insurgency, according to a military source quoted by Reuters; last weekend’s attack was the latest in a series of explosions targeting oil and gas pipelines and attributed to the movement.

In 2012, the railway,  which is owned and used by Cerrejon, carried 32.7 million metric tons (mt) of coal from its La Guajira province mine to Puerto Bolivar port, the company said; Cerrejon is a joint venture between major London-headquartered Anglo American plc, BHP Billiton and Swiss-based Glencore Xstrata plc.

Repairs were under way this week by Cerrejon workers with the help of Colombian military forces who secured the scene, according to a company statement. In all, Cerrejon’s property witnessed seven attacks 2012.

Cerrejon spokesman Juan Carlos Restrepo told Reuters it was unclear how long it would take to reopen the rail line, but said stocks at the port would cover export requirements until it reopened.

“Cerrejon condemns this violent action that generates economic and environmental damage and at the same time creates a high risk of fatalities,” Cerrejon’s statement added.

The explosion was the latest in a series of setbacks to the company this year and one of Latin America’s top mining nations after a month-long Cerrejon worker strike in February followed by a seven-week stoppage at Colombia’s No. 2 miner, Alabama-based Drummond.