The Greenbushes lithium mine is doubling down on its expansion, with its US and Chinese owners committing to a new $500 million investment even before a $320 million first-stage upgrade is completed.

Talison Lithium, a partnership between China’s Tianqi and US group Albemarle, today announced its board had approved a second-stage expansion of Greenbushes at a cost of $516 million.

The expansion, on top of a $320 million upgrade due for completion in April, will double the mine’s production to 1.95 million tonnes a year of lithium concentrate a year from 2020.

The new expansion covers construction of a third lithium concentrate plant with a capacity of 520,000t of concentrate and new crushing plant.

“The expansion, plus de-bottlenecking of the existing lithium concentration plants, will increase the lithium concentrate production capacity at Greenbushes by 608,000 tonnes per annum to approximately 1.95 million tonnes per annum,” Talison said in a statement.

But the lithium miner also signalled that further expansion at the site was in prospect, with another lithium concentrate plant “possibly” being “commissioned in 2022, subject to the timing of final board approval”.

Talison’s announcement of the project also comes before a $320 million upgrade at the site is actually completed and commissioned.

“The expansion ensures that Talison is well positioned to provide its shareholders with a quality and secure supply of lithium concentrate to service the expected future growth of the global lithium market,” Talison said.

It lifts the total investment in WA lithium underpinned by Greenbushes, south-east of Perth, to nearly $2 billion, and will increase the number of new permanent jobs created at the mine to 250.

The upgrades will feed new value-adding lithium hydroxide plants that are being developed or are planned by Tianqi and Albemarle as the companies position themselves to take full advantage of rising global demand for lithium from battery and carmakers.

Talison Lithium’s chief executive, Lorry Mignacca, said he was delighted that the expansion had been approved, and work would commence as soon as the necessary regulatory approvals were completed.

“Greenbushes is a truly world-class operation with the capacity for significant expansion to underpin the lithium supply needs of our shareholders,” Said Lorry Mignacca.

“In addition to the major investment by Talison in Greenbushes, the expanded lithium concentrate production will underpin the development of world-class lithium hydroxide production plants in WA driven by Tianqi and Albemarle.”

Site works are expected to begin in the March quarter, with the construction workforce to peak at more than 300.

Talison is a privately owned joint venture between the Chinese company Tianqi Lithium Corporation (51 per cent) and the American company Albemarle (49%).