09:21 AM EDT, 10/14/2025 (MT Newswires) -- Standard Lithium ( SLI ) , near 52 week highs in Canada and the United States, was at last look down near 1% in US premarket trade after saying Tuesday that Smackover Lithium filed a definitive feasibility study for the South West Arkansas project.

Smackover Lithium is a 55:45 joint venture between Standard Lithium ( SLI ) and Equinor.

SLI in a statement said the study contemplated production capacity of 22,500 tonnes per year of battery-quality lithium carbonate over a 20-year operating life, producing 447,000 tonnes (Proven Reserves) of lithium carbonate equivalent, or 38% of the in-situ Measured and Indicated Resources of 1,177,000 tonnes LCE.

Smackover added the report is highlighted by a 20.2% unlevered pre-tax internal rate of return, with competitive average cash operating costs of US$4,516 per tonner and all-in costs of US$5,924/t over the operating life. The class III capex estimate was US$1.45 billion, which includes a 12.3% Monte Carlo risked contingency.

Construction is expected to start in 2026, with first production targeted in 2028.

Shares in SLI rose 3.75% in Canada last Friday.