Chilean state-run miner Codelco, the world's largest copper producer, presented its final offer in contract negotiations with three unions at its giant Chuquicamata mine on Friday as workers threatened to strike if the company does not meet demands.
Workers from the unions involved had rejected last weekend a proposal by the company, which included a $19,700 bonus per worker and a 1.2% raise, but only if the deal was signed before Wednesday.
However, the final proposal delivered by Codelco includes smaller bonuses of about $14,150 per worker - eliminating the early signing bonus - and the same salary readjustment of 1.2%.
"The attendees have already stated categorically that if [the final offer] is similar, the strike option would be the only way forward," the unions said in a joint statement.
The workers will vote on the final proposal on May 28 and 29.
Codelco is seeking to transform the 100-year-old open-pit deposit at Chuquicamata into an underground mine. The plan is part of a 10-year, $39 billion overhaul of Codelco's key operations as it seeks to maintain output despite rapidly falling ore grades at its deposits.
(Reporting by Fabian Cambero; writing by Cassandra Garrison, Editing by Chizu Nomiyama)