BOGOTA, Jan 26 (Reuters) - Colombia's top thermal coal mine Cerrejon and its largest union have returned to talks in a bid to avoid a strike over pay and benefits, the two sides said on Friday.
A 10-day voting period for union members to decide whether to stop work after failed talks ends on Monday afternoon. A strike could begin within three days of the close of voting.
"By request of the company we returned to the negotiating table on Thursday," Aldo Amaya, president of the Sintracarbon union, told Reuters. "We are willing to look for a new agreement and we have started working on a deal, but haven't yet touched the issue of increments for salary increases."
The company, equally owned by BHP Billiton BLT.L , Anglo American AAL.L and Glencore GLEN.L , offered a 2018 salary increase of 5.9 percent during last week's talks. The union has demanded 12 percent and increased health and education benefits.
A source at the company, which employs 5,000 people, said Cerrejon was optimistic the two sides could reach a deal.
Production and exports at Cerrejon fell for a third straight year in 2017, when it mined 31.7 million tonnes of coal, as heavy rainfall affected operations, the owners said this month.
Cerrejon accounts for 37 percent of Colombia's coal output, the world's fifth-largest exporter of the mineral. Coal is the country's second most important export.
The last strike at Cerrejon, which produces coal at its open pit mine in northern La Guajira province, was in February 2013 and lasted 32 days.