The company said the first train loaded with 6431 tonnes of coal was accompanied on its departure by local staff, students and residents bearing white flags and balloons.

"It is satisfying to see activities resume, it inspires us as a company and shows that despite everything we keep going forward, always generating progress for the region and the country," said train controller Harold Diaz.

The mine, Colombia’s largest open-pit coal operation, has yet to operate at installed capacity after employees signed a three-year labor accord March 11 and began returning to work, Cerrejon spokesman Juan Carlos Restrepo told Bloomberg.

“We’re exporting again,” Restrepo said.

“We’re not at 100%, but it’s a matter of waiting a few more days.”

Cerrejon and union Sintracarbon signed a new collective bargaining agreement Monday, ending the strike that began on February 7 and immediately restarting operations.

According to a release from Cerrejon, the new agreement “includes a wage increase of 5.1% for the first year, immediately applies the bonuses until 2015 since the agreement was extended to three years, establishes better conditions for housing loans, educational grants, scholarships, and seniority bonuses, and also improves the service provision of worker health and transportation, among other items.”

The strike cost the mine almost 3 million tons in output, according to Bloomberg.

"All of us lost with the strike,” stated Cerrejón's president, Roberto Junguito.

“Now our priority is to safely re-establish operations, recover the confidence of our customers, and focus on the expansion projects and on investment in social initiatives that continue supporting the sustainable development of La Guajira.”

Cerrejon, owned by BHP Billiton, Xstrata and Anglo American, produced 34.6 million tons of coal last year, according to its website.

According to the World Coal Association, Cerrejon and Colombia’s second-largest coal producer Drummond together accounted for 80% of Colombia’s coal exports of about 75 million tons in 2011.

Drummond restarted operations last week after a three-week suspension due to a port accident.