Patagonia Lithium’s Well 7 at Formentera delivered a lithium assay of 270ppm at 282m, close to the project average, alongside encouraging porosity and specific yield results that underpin production potential. Drilling will now shift to the Cilon concession, targeting a high-grade lithium zone.
- 270ppm lithium assay at 282m depth
- High specific yield up to 34% in sandy units
- Well 7 drilled to 476m, hitting clay basement marker
- 72-hour pump test planned to assess aquifer flow
- Drilling to commence at Cilon concession with historic 1,122ppm sample
Lithium Concentration Near Project Average at Formentera Well 7
Patagonia Lithium Ltd (ASX:PL3) has reported a lithium assay of 270ppm from Well 7 at its Formentera Lithium Project, measured at 282 metres depth. This result sits just shy of the project average of 296ppm, reinforcing the consistency of lithium concentrations across the basin. The well was drilled to a final depth of 476 metres, where a 50-metre thick clay layer was intersected, interpreted as the basement and a marker for the Vizcachera Formation.
Porosity and Specific Yield Indicate Promising Aquifer Properties
The well’s porosity profile exceeded expectations, with total porosity ranging from 15% to 42% and specific yield (SY) values between 3% and 34%. Notably, the sandy unit that yielded the 270ppm lithium assay exhibited a specific yield between 8% and 23%, commencing at 279 metres. These figures suggest a reservoir with good water transmissivity and potential for sustainable lithium brine extraction. However, despite nine of 18 packer tests being successful, the brine flow was somewhat limited, which contrasts with the porosity data and the volcanic and gravel lithologies encountered.
Preparation for Pump Testing and Next Drilling Steps
Well 7 is currently being lined with 3-inch slotted PVC pipe to facilitate a 72-hour pump test designed to better understand aquifer flow rates and production viability. This test will complement ongoing pump tests at other wells on the project. Meanwhile, drilling preparations are underway at the nearby Cilon concession, where a drill pad has been completed. Cilon holds promise following a 2023 subsurface sample that assayed 1,122ppm lithium, significantly higher than Formentera’s current average. Patagonia Lithium plans to use the remaining 125 metres of its current drill contract to extend the Mineral Resource Estimate boundary by targeting this high-grade zone.
Geophysical Data Supports Targeting Strategy
Magnetotelluric (MT) geophysics has delineated a sandy lithological unit associated with the highest lithium assays, guiding the placement of Well 8 on the Cilon concession. The drill site was relocated slightly south to avoid unstable wet soils, ensuring safer and more effective drilling conditions. These geophysical insights align with previous drilling results and passive seismic surveys that have identified the clay basement marker and deeper aquifer sequences, which are critical for resource modelling and extraction planning.
Resource Estimate Remains Robust Amid Continued Exploration
Patagonia Lithium confirmed that no material changes affect the existing Mineral Resource Estimate (MRE) of 551,400 tonnes of lithium carbonate equivalent (LCE), comprising 14,800 tonnes indicated at 393mg/L lithium and 536,600 tonnes inferred at 292mg/L. The company’s Executive Chairman Phillip Thomas highlighted the value of the high-porosity sandy units for production pumping rates and the strategic importance of expanding drilling to Cilon to capture higher-grade lithium zones. Further assay results from Well 7’s pending samples and the upcoming pump tests will be pivotal in refining the resource model and guiding development plans.
Bottom Line?
Patagonia Lithium’s latest drilling confirms consistent lithium grades and strong aquifer properties, setting the stage for resource expansion at Cilon and critical pump test results to define production potential.
Questions in the middle?
- Will the 72-hour pump test at Well 7 confirm sufficient brine flow to support commercial extraction?
- How will the high-grade lithium zone at Cilon impact the overall resource estimate and project economics?
- What do the limited brine flows in some packer tests imply for reservoir heterogeneity and extraction strategies?