Uncertainty Remains as Patagonia Lithium Awaits Pump Test Results at Well Seven

Strong Brine Quality Confirmed at 350m Depth

Patagonia Lithium Ltd (ASX:PL3) has reported robust brine extraction results from Well Seven JAM 26-07 at its Formentera Lithium Project in Argentina. Eleven out of thirteen packer assay tests at 350 metres depth successfully extracted approximately 200 litres of brine, delivering key metrics that underscore the brine’s high lithium potential. The latest assay recorded a specific gravity of 1.11 g/cm³, electrical conductivity of 173.6 mS/cm, and total dissolved solids at 86.6 ppt, figures that align with industry benchmarks for lithium-rich brines.

Executive Chairman Phillip Thomas highlighted the significance of these findings, noting the flow rates between 200 and 857 litres per hour and the geological advantage of a large sandstone unit with high porosity capped by a clay aquitard. This stratigraphy is conducive to lithium concentration, which may allow the company to expand its Mineral Resource Estimate (MRE) domain. The current MRE stands at 551,400 tonnes of lithium carbonate equivalent (LCE), comprising 14,800 tonnes indicated and 536,600 tonnes inferred, based on the July 2025 update.

Geological Setting Supports Lithium Concentration

The well’s core samples reveal a thick interval of semi-consolidated to unconsolidated medium to fine sands with moderate to high visual porosity, key for brine storage and flow. Above this sandstone lies a clay aquitard, which acts as a seal preventing lower conductivity brines from diluting the lithium-rich fluids. This geological setup, combined with episodic volcaniclastic inputs and iron oxide enrichment, indicates a favourable environment for lithium-bearing minerals.

These porosity and lithology insights build on previous results from Well Six, where Patagonia Lithium reported exceptional core porosity reaching 40% and lithium assays up to 412 ppm, reinforcing the project’s substantial aquifer potential. The current drilling and packer testing at Well Seven continue this momentum, with the well projected to reach 600 metres depth, aiming to further delineate the brine system’s extent and quality. Such findings are consistent with the company’s earlier 40% core porosity results and ongoing drilling progress.

Pump Tests and Next Steps

While Well Seven’s packer tests have yielded promising flow rates and brine quality, Patagonia Lithium is concurrently conducting 72-hour pump tests on Wells 1 through 4 to monitor brine level changes and aquifer connectivity. These longer-duration tests will provide critical data on sustainable pumping rates and aquifer transmissivity, informing future resource estimates and potential production scenarios.

Further porosity surveys using borehole magnetic resonance (BMR) and extended pump testing are planned before updating the MRE. The company also confirms that all sampling and assay procedures adhere to strict chain of custody and quality control protocols, with brine samples analysed at SGS and Alex Stewart laboratories, both ISO/IEC 17025:2017 certified.

The Formentera/Cilon Lithium Project, situated in Argentina’s lithium triangle, remains a cornerstone asset for Patagonia Lithium, complementing its other holdings in Salta Province and Brazil. The company’s steady progress in drilling, assay results, and environmental permitting continues to position it as a notable player in lithium brine exploration, with a clear pathway towards resource expansion and eventual production.