Funds raised would be used to progress Vulcan's zero-carbon lithium development in Europe, which has an offtake deal with the battery unit of South Korea's LG Chem.

Throughout the strike, the miner maintained the extended walk-off had not hit its output of lithium from Chile.

A bidding war is heating up for Canadian miner Millennial Lithium Corp. as Chinese firms compete to secure key elements needed for electric-vehicle batteries.

Already the fourth top producer of lithium worldwide, Argentina's national and local governments are now looking to speed up development.

Industry and Information Technology Minister, Xiao Yaqing, said the government will encourage consolidation.

Chile's SMA environmental regulator in 2016 charged SQM with overdrawing lithium-rich brine from the Salar de Atacama salt flat, prompting the company to develop a $25 million plan to bring its operations back into compliance.

The union said in a statement that the latest deal offered nothing beyond two prior proposals that were also rejected.

Lithium prices have jumped to their highest in more than three years.