Lithium Argentina AG (NYSE: LAR) announced an updated mineral resource and reserve estimate for its Cauchari-Olaroz brine operation in Argentina's Jujuy Province, according to a company press release.

The updated estimate increased measured and indicated resources by 42% to 28.1 million tonnes of lithium carbonate equivalent (LCE), compared to 19.9 million tonnes LCE in the 2019 estimate. The average grade decreased slightly to 562 mg/L lithium from 592 mg/L previously. Inferred resources increased to 9.6 million tonnes LCE at 567 mg/L lithium, up from 4.7 million tonnes LCE at 592 mg/L.

The estimate was completed by Aquatec and Groundwater Insight, Inc. with an effective date of December 31, 2025. It incorporates additional drilling that expanded the resource area by approximately 20 kilometers south of the previous footprint, along with production well sampling data and a basin-wide hydrological model.

The company updated mineral reserves to 1.4 million tonnes LCE, reflecting its Stage 1 operation plan with 40,000 tonnes per annum capacity over a 35-year operating period from 2026 through 2060. This aligns with the original 40-year project life after accounting for brine inventory and production to date.

Lithium Argentina filed applications for environmental permits and the Incentive Regime for Large Investments (RIGI) for Stage 2 development in December 2025. Stage 2 targets an additional 45,000 tonnes per annum of LCE capacity beyond the current 40,000 tonnes per annum Stage 1 operation.

The company operates Cauchari-Olaroz through a partnership that includes 44.8% ownership by Lithium Argentina, 46.7% by Ganfeng, and 8.5% by JEMSE, a mining investment company owned by Argentina's Jujuy Province government.