(Updates with labor negotiations context)
By Antonio De la Jara
SANTIAGO, Jan 4 (Reuters) - Unionized workers at Glencore Plc's Lomas Bayas copper mine in Chile rejected a final contract offer and began government-facilitated mediation on Thursday to avoid a strike, the union said, adding that they were still far from agreement.
Union president Pedro Valdivia said workers agreed to lay down tools on Jan. 10 if no agreement was reached during the mediation.
New labor laws and rising copper prices have emboldened miners throughout Chile, the world's top producer of the red metal.
"The atmosphere is tense. For now, we're far from reaching a deal," Valdivia said in an interview.
Glencore did not immediately respond to a request for comment.
A 105-member union at Teck Resources Ltd's Quebrada Blanca mine walked off the job for a week last month.
In late November, workers at BHP's Escondida mine, the world's largest, also put down their tools for 24-hours following layoffs there.
Chile's National Mining Society (Sonami) has said more than 30 pending negotiations over expiring workers' contracts in 2018 could curb output if strikes continue to hit the sector.
Lomas Bayas produced 67,000 tonnes of copper between January and October of 2017.
Reporting by Antonio De la Jara, writing by Dave Sherwood; Editing by Andrew Hay