The bombing occurred on Sunday morning near its Oreganal pit in the complex’s south mine sector and came just hours before the mine’s officials headed back to the negotiation table to restart talks to end a walkout that began earlier this month.

According to local media sources, the strike is costing Cerrejon millions a day and is leaving as much as 100,000 tons of coal in the ground daily.

“As a result of such terrorist action no human losses were caused but four trucks that were parked as a consequence of the strike that has affected the company for 17 days were seriously damaged,” the company said.

“Cerrejon strongly rejects this terrorist action against the company, which causes considerable economic and moral damage to the company [and] calls for the solidarity of its workers and of all of the community, to reject this type of action against our company which responsibly generates employment, welfare and development for the region.”

Sintracarbon union president Igor Diaz denied any involvement in the incidents to Dow Jones Newswires and joined Cerrejon in condemning the attack.

“It's a lamentable act that we emphatically reject," Diaz said.

“[The bombing was] just as much against the workers strike” as against the company itself, he added.

Cerrejon is owned by Xstrata, Anglo American and BHP Billiton.

Dow Jones reported that Colombia was exporting just one-fifth of its normal levels, as its other primary export coal producer, Drummond, also had its shipments stop.

In Drummond’s case it was due to the February 6 suspension of its port operating license following a vessel accident that might have caused environmental damage.

In a recent statement Drummond said about 300 tons of coal were dumped into the Caribbean Sea in an attempt to prevent one of its barges from sinking.

Colombia is among the top coal producing countries in the world and is the fourth-largest exporter globally.