Patagonia Lithium Drills 40% Porosity at Formentera Brine Project

Patagonia Lithium Drills 40% Porosity at Formentera — A Result That Could Reshape the Resource Estimate

Patagonia Lithium Ltd (ASX: PL3) has delivered one of its most significant technical milestones to date, with core porosity testing from Well Six at its Formentera Lithium Brine Project in Argentina returning exceptional Relative Brine Release Capacity (RBRC) results — peaking at 40% at 160 metres depth. The Patagonia Lithium Formentera lithium brine porosity results span from 20% at 478 metres to 40% at 160 metres across six core samples, independently confirmed by specialist firm Daniel Stephens and Associates.

These results closely align with the earlier BMR Gamma survey, which returned an average porosity of 22% across the entire 462-metre log and a maximum of 39% — further validating the subsurface brine system at Formentera.

With Well Seven (JAM 26-07) now drilling at 218 metres depth and a sixth assay packer test already completed, momentum at Formentera is building rapidly. The company holds a current Mineral Resource Estimate (MRE) of 551,400 tonnes of Lithium Carbonate Equivalent (LCE) at 294 mg/L, and the latest porosity data suggests meaningful upside to that figure.

Why Porosity Is the Number Every Lithium Brine Investor Should Be Watching

When evaluating a lithium brine project, investors often focus on lithium concentration — but porosity is equally critical, and in some ways more so. Here's why.

What Is Relative Brine Release Capacity (RBRC)?

In a lithium brine system, lithium is dissolved in water (brine) that is stored within the pores and spaces of underground rock and sediment. The RBRC measures how much of that brine can actually be released and pumped to surface from a given volume of rock.

Think of it this way: two aquifers might both contain brine with identical lithium concentrations, but if one has 40% porosity and the other has only 5%, the first aquifer will yield dramatically more lithium per unit of ground. Higher porosity means:

• More brine stored per cubic metre of aquifer
• Higher achievable pump rates
• A larger plant size can be economically supported
• Ultimately, a larger resource and potentially higher project valuation

The Industry Benchmark

Industry specialists consider RBRC values above 6% to be outstanding. The Patagonia Lithium Formentera lithium brine porosity results from Well Six ranged from 20% to 40% — multiples above that threshold across all six core samples tested.

Executive Chair and Senior Geologist Phillip Thomas commented: "This is great news and it confirms the high values we achieved in the BMR Gamma survey. RBRC is a key statistic and is just as important as lithium concentration. Without porosity nothing comes out of the aquifer! We look forward to well 7 results but pump rates from the packer tests are very encouraging."

A Standout Aquifer Is Taking Shape

Well Six (JAM 26-06) was drilled vertically to 488 metres using a Boart Longyear LT190 machine with HQ3 diameter core recovery exceeding 95%. The well recorded a lithium concentration of 412 ppm, announced in March 2026, and the latest RBRC data now adds a critical second dimension to that result.

The most porous sections of the aquifer sit within zones 7 and 8, where the 412 ppm lithium assay was obtained. The aquifer extends across a zone of 222 metres — a substantial vertical thickness that amplifies the significance of the high porosity readings.

Critically, the BMR Gamma survey independently confirmed the porosity picture across the full 462-metre log:

• Average porosity: 22% — well above the 6% outstanding threshold
• Maximum porosity: 39% — approaching the 40% peak measured by RBRC core testing
• Consistency of results across two independent methodologies adds significant technical credibility

This dual-method validation — RBRC core analysis from Daniel Stephens and Associates alongside the BMR Gamma geophysical log — is an important quality signal. Furthermore, it reduces geological uncertainty and strengthens the case for a resource upgrade once Well Seven data is incorporated.

Well Seven Is Already Underway — The Pace Is Accelerating

While the Patagonia Lithium Formentera lithium brine porosity results are generating justified attention, the company has not paused. Well Seven (JAM 26-07) is actively drilling, currently at 218 metres depth, with the sixth assay packer test already completed at Well Six.

The company's upcoming catalysts are well-defined:

1. Well Seven (JAM 26-07) assay results — lithium concentration data pending
2. Well Seven RBRC/porosity analysis — to confirm whether the exceptional porosity extends laterally
3. Passive seismic survey results — pending, to map subsurface structure
4. BMR Gamma porosity survey — pending for Well Seven
5. Updated Mineral Resource Estimate — to be computed once Well Seven data is received

Well JAM 26-07 is located on Line 7411300, in close geographic proximity to JAM 26-06, providing continuity of geological interpretation across the programme.

The Existing Resource — and Why an Upgrade Is Plausible

Patagonia Lithium's current MRE, lodged in July 2025 following a 319% increase in LCE, stands as follows:

The company confirms that all material assumptions underpinning this MRE remain unchanged. However, the significance of the Patagonia Lithium Formentera lithium brine porosity results is that they directly feed into the variables used to calculate drainable resource volumes.

A higher RBRC means more extractable brine per unit of aquifer. When applied across a 222-metre aquifer zone with consistently high porosity, the arithmetic points toward upside.

An updated MRE incorporating Well Seven data is planned. If Well Seven replicates or extends the porosity and lithium concentration results seen at Well Six, the conditions for a further resource upgrade would appear to be in place — though investors should note that a formal estimate awaits completion of the full dataset.

Formentera in Context — A Project With Scale

The Formentera/Cilon project sits within the Salar de Jama in Jujuy Province, Argentina, covering 19,500 hectares in the lithium triangle — one of the world's premier lithium brine regions. Patagonia Lithium also holds the Tomas III project at Incahuasi Salar in Salta Province (580 hectares), where MT geophysics has returned prospective results.

In Brazil, the company holds 41,746 hectares of exploration concessions across five packages, targeting ionic rare earth element (REE) clays, niobium, antimony, and lithium in pegmatites. The Brazilian footprint includes tenements adjacent to CMOC's niobium operation in Goiás state — the largest niobium producer in Brazil, with production of 10,024 tonnes per annum.

Since listing on 31 March 2023, the company has moved through surface sampling, magnetotelluric (MT) and passive seismic geophysics, and now seven drill holes — a rapid exploration cadence that has produced consistently strong results in lithium assays, porosity, and pump tests.

Why Investors Should Keep a Close Eye on PL3

Patagonia Lithium is at an inflection point. The convergence of a strong existing resource base, exceptional porosity results from Well Six, and an active drilling programme at Well Seven creates a near-term catalyst runway that is unusually well-defined for a company at this stage of development.

Key reasons to monitor PL3 include:

• Porosity results that are multiples above industry benchmarks, independently confirmed by two methodologies
• A 222-metre aquifer zone combining high lithium concentration (412 ppm) with exceptional brine release capacity (up to 40%)
• An active drill programme with Well Seven underway and multiple pending datasets that could support an MRE update
• An existing MRE of 551,400t LCE that grew 319% in July 2025, with the latest results suggesting further upside
• A diversified project portfolio spanning Argentina and Brazil, providing multiple exploration fronts
• A compact capital structure with 207.1 million shares on issue

The Patagonia Lithium Formentera lithium brine porosity results demonstrate that Formentera is not merely a lithium brine project — it is a high-porosity, high-capacity brine system with the physical characteristics needed to support a substantive operation. With Well Seven actively drilling and an MRE update on the horizon, the next several months represent a pivotal window for investors tracking the company's development.

Understanding Lithium Brine Systems

How Does Lithium Brine Form?

Lithium brines develop through a complex geological process spanning millions of years. The process begins when lithium-bearing rocks undergo weathering and erosion, releasing lithium ions into groundwater systems. These lithium-rich waters then flow into closed basins called salars — flat, salt-covered depressions found primarily in arid regions.

In these basins, evaporation concentrates the lithium along with other dissolved minerals. Over geological time, this process creates layers of sediment that can store lithium-rich brine in their pore spaces. The amount of brine that can be extracted depends heavily on the porosity of these sediments.

Why Does Porosity Matter in Resource Calculations?

Porosity directly affects two critical factors in lithium brine projects:

1. Storage Capacity: Higher porosity means more space for brine storage within the aquifer
2. Flow Rates: Porous formations typically allow better brine flow to extraction wells

When geologists calculate a Mineral Resource Estimate for a brine project, they use porosity as a key variable:

Drainable Resource = Aquifer Volume × Average Porosity × Lithium Grade × Specific Yield

The specific yield represents the percentage of stored brine that can actually be extracted. Industry studies show that projects with higher porosity generally achieve better specific yields, making them more economically attractive.

How Does Formentera Compare to Established Operations?

Established lithium brine operations provide useful context for evaluating porosity results:

• Atacama Salar (Chile): Average porosity of 10–15% in producing zones
• Clayton Valley (Nevada): Porosity ranges from 8–20% across different formations
• Salar de Olaroz (Argentina): Average porosity of approximately 12–18%

The 40% peak porosity recorded at Formentera significantly exceeds these benchmarks. However, investors should note that commercial viability depends on multiple factors, including lithium grade, depth, and processing costs.

Technical Methodology Behind the Results

The RBRC Testing Process

The Relative Brine Release Capacity analysis involves several steps to determine how much brine can be extracted from rock samples:

1. Core Sampling: Six samples were collected from different depths in Well Six
2. Laboratory Testing: Samples were sent to Daniel Stephens and Associates in New Mexico, USA
3. Saturated Testing: Cores were saturated with brine under controlled conditions
4. Release Measurement: The amount of brine that drains under gravity is measured and compared to the total sample volume

This methodology provides a reliable estimate of how much brine could be extracted from the aquifer during production operations.

BMR Gamma Survey Validation

The BMR Gamma survey uses geophysical logging tools lowered into the drill hole to measure rock properties continuously along the entire 462-metre interval. This technique provides:

• Continuous Data: Porosity measurements at every depth interval
• Independent Verification: Results obtained using a different methodology than core testing
• Full Coverage: Data across the entire drilled section, not just selected samples

The close correlation between BMR Gamma results (average 22%, maximum 39%) and RBRC testing (range 20–40%) strengthens confidence in the aquifer's porosity characteristics considerably.

Next Steps and Timeline Considerations

The completion of Well Seven drilling and subsequent analysis will be critical for several reasons.

Lateral Continuity: Well Seven sits approximately 800 metres from Well Six, testing whether the high porosity and lithium grades extend across the project area.

Resource Modelling: Additional data points allow geologists to create more accurate three-dimensional models of the aquifer system.

Economic Assessment: Higher confidence in resource continuity enables more detailed economic studies to assess project viability.

The company has indicated that an updated MRE will be calculated following completion of Well Seven analysis. Industry observers note that resource upgrades in lithium brine projects often occur when new drilling confirms both grade and porosity continuity across the deposit. In addition, with two independent methodologies already aligning so closely at Well Six, the technical foundations for that upgrade are increasingly well-established.

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