Standard Lithium (SLI) and Equinor's (EQNR) joint venture, Smackover Lithium, said Tuesday that it has filed a definitive feasibility study on its South West Arkansas project, recommending that the project is ready for a final investment decision.

According to the study, development will take 34 months from construction to commercial operation, with construction anticipated to begin in 2026 following a final investment decision and first production targeted in 2028, Smackover Lithium said.

The study estimates production capacity of 22,500 tonnes per annum of battery-quality lithium carbonate over a 20-year operating life, producing 447,000 tonnes of lithium carbonate equivalent, according to the statement.

The study highlighted a 20.2% unlevered pre-tax internal rate of return and an all-in capital expenditure estimate of $1.45 billion, Smackover Lithium said.

Shares of Standard Lithium and Equinor were down 7.3% and 2.6%, respectively, in early trading Tuesday.