Anson Resources reveals a 46% increase in effective porosity from historical core analysis at its Green River Lithium Project, alongside strong Drill Stem Test results that underpin an upcoming resource upgrade.
- Effective porosity averages 8.8%, up from 6% in prior JORC estimate
- Drill Stem Test confirms high-pressure, high-temperature brine flow
- Geological consistency across key wells supports resource confidence
- New data to refine 3D reservoir models and production plant design
- JORC resource upgrade underway incorporating updated porosity data
Significant Porosity Upgrade from Historical Core
Anson Resources Limited (ASX:ASN) has uncovered a substantial revision to reservoir properties at its Green River Lithium Project in Utah. Analysis of diamond core samples from the Floy Unit 1 Well reveals an average effective porosity of 8.8% within the Mississippian Unit, a 46% increase over the 6% figure previously applied in the existing JORC resource estimate. This higher porosity, observed in vuggy dolomite formations, suggests greater brine storage capacity than earlier models assumed.
Drill Stem Test Validates Reservoir Pressure and Temperature
Complementing the porosity data, a Drill Stem Test (DST) conducted over a 30-foot interval at Floy Unit 1 recorded brine flowing up 7,630 feet of tubing under a pressure of 6,046 psi and at a temperature of 68.9°C. These parameters align closely with historical DST results from the Mt Fuel-Skyline Geyser and Grand Fault wells, which span the 25-kilometre project area. The consistency in pressure and temperature across these wells reinforces the geological model and informs the design considerations for the future lithium brine production plant.
Geological Continuity Enhances Resource Confidence
The Green River Project's key structural features, including the Ten Mile Graben and Little Grand Wash Fault, contribute to high-pressure, fractured reservoirs with vertical porosity conducive to brine extraction. The Floy Unit 1 Well, located 11 kilometres southeast of the Mt Fuel-Skyline Geyser Well, exhibits similar geological characteristics, lending weight to the extrapolation of porosity and pressure data across the project. This geological continuity is crucial for refining the Petrel 3D model that underpins Anson's lithium resource estimates.
These findings dovetail with recent drilling fluid assays at Mt Fuel-Skyline Geyser which reported lithium grades up to 148ppm, supporting a significant resource upgrade currently underway. The integration of improved porosity data with grade information bolsters the project's development case and aligns with ongoing engineering and financing efforts for the planned production plant lithium grades up to 148ppm.
Implications for Production and Resource Modelling
The enhanced porosity figures will be incorporated into updated JORC resource calculations and reservoir simulations, improving estimates of brine flow rates and transmissibility. These parameters are vital for designing an efficient Direct Lithium Extraction (DLE) processing plant tailored to the reservoir’s pressure and temperature conditions. Although Anson’s recent drilling at Mt Fuel-Skyline Geyser encountered technical challenges limiting direct measurement of brine flow, the historical DST data and new core analyses provide a robust foundation for resource modelling and production planning.
While the porosity increase is derived from historical core and modelling, it remains to be seen how these improvements translate into operational performance. The company’s next steps include further drilling to extend the resource base and validate these findings in situ.
Bottom Line?
Anson’s updated porosity data and consistent DST results strengthen the technical case for a resource upgrade and production design but leave open questions about translating these gains into operational output.
Questions in the middle?
- Will the updated porosity translate into improved lithium recovery rates in production tests?
- How will the ongoing JORC resource upgrade impact Anson’s project valuation and financing prospects?
- What further drilling or testing is planned to confirm reservoir continuity and flow characteristics?