(New throughout, adds details, background, comments)
BOGOTA, March 16 (Reuters) - The majority of members at two unions of Colombian coal miner Cerrejon voted in favor of a strike relating to a dispute over pay and benefits in the contract, a union leader said on Monday.
A strike at Cerrejon, which is owned equally by BHP Group , Anglo American and Glencore, could cut the company's coal production and sales outside of Colombia, the fifth biggest coal exporter in the world.
Coal is the second largest generator of foreign currency for the Andean country after oil.
"With a vote strongly in favor of industrial action, the members of the biggest union have just declared a strike at Cerrejon," Igor Diaz, president of the larger Sintracarbon union, said in a message to Reuters, adding that 98.8% of the 3,631 votes supported downing tools.
While the start date for the strike has yet to be decided, rules mean the walk out can begin in 10 days.
The initial 20-day negotiation period between the miner and Sintracarbon ended on Feb. 15 but both groups agreed to a further 20 days of negotiations, which expired on March 6.
Sintracarbon and Sintracerrejon, the minority union, called for their members to vote between striking and seeking arbitration.
A source from Cerrejon told Reuters that despite the decision by the unions, talks will continue to try to avoid the strikes.
A meeting between the company and the unions is scheduled for Wednesday, Diaz said, adding that reaching an agreement will be complicated.
Cerrejon is trying to reduce, freeze and eliminate benefits for employees using the fall in coal prices as an excuse while ignoring the depreciation of the Colombian peso against the dollar, the union leader said.
The company exported 26.3 million tonnes of coal in 2019 and has 5,896 workers, of which 4,600 are union members.
Sintracarbon is demanding a pay rise of 7.8%, as well as additional health, education and accommodation benefits. The mining company offered a rise of 3.8% to match inflation in 2019.
The last strike at Cerrejon was in Feb. 2013 and lasted 32 days. Last year, coal prices fell to an average of $51.40 per tonne, down from $82.50 per tonne in the previous year, according to the Ministry of Mining and Energy.
Cerrejon, located in La Guajira province, also controls a 150-kilometer (90-mile) rail line and a seaport that receives ships which can carry up to 180,000 tonnes of cargo. (Reporting by Luis Jaime Acosta Writing by Oliver Griffin; Editing by Sandra Maler and David Gregorio)