Following the acquisition and interpretation of new 2D and 3D seismic surveys, and nearby well data, Vulcan delivered a maiden indicated lithium brine resource for Taro of 830,000 tonnes of lithium carbonate equivalent grading 181 milligrams per tonne, with an inferred 1.44Mt at 181mg/L.
Previously, all Taro's resources were indicated, determined in August to be 1.42Mt at 181mg/L.
The updates have increased the junior's overall lithium brine resource in the Upper Rhine Valley to 16.19Mt at 181mg/L, which it claims is not only the largest lithium resource in Europe - but one that can produce lithium hydroxide for batteries at the lowest emissions in the world.
Taro's higher confidence indicated resource is being added to the ongoing prefeasibility study.
Taro has additional upside, particularly at depth, but there are no geothermal wells penetrating the brine aquifers in deeper sandstones, or the uppermost highly faulted and fractured and altered granitic basement.
Over the past year, Vulcan has improved 3D modelling of the Permo-Triassic strata and faulting underlying Taro and, using a geothermal well 18km outside Taro, has been better able to model the hydrogeological characteristics of the brine-rich zones.
It has also been able to recover brines from the Upper Rhine Graben and complete bench-scale lithium extraction test work to recover lithium, with recoveries over 90%.
Optimisation is now underway as part of the PFS.
Vulcan earned 51% of Taro from Global Geothermal Holding, having spent €500,000. It is now spending a further €500,000 to move to 80% over the next two years.
The company is fully-funded for the PFS following an investment from the European Union's InnoEnergy, and the proceeds of a A$4.8 million placement at 40c in September.
Vulcan is targeting European battery makers, and is located in the heart of Germany's automotive sector.
The PFS is expected to be completed before year's end.
Vulcan shares, which have traded as low as 12c this year, were up 3% today to $1.71, but hit an all-time record of $1.98 earlier in the session.