Prominence Energy Limited (ASX:PRM) has announced results from a CSIRO Kick-Start study conducted at its Eyre Peninsula Project in South Australia, with hydrogen detected in fluid inclusions in all 28 successfully analysed rock samples and two potential natural hydrogen generation mechanisms identified.

Key Points

  • Hydrogen detected in fluid inclusions in all 28 successfully analysed rock samples from the Eyre Peninsula Project in South Australia
  • Two potential natural hydrogen generation mechanisms identified: radiolysis from uranium and thorium enriched rocks, and water-rock reactions with iron-bearing rocks
  • The highest hydrogen measurement recorded was 7.72 mmol/kg of rock, from a quartz vein in the Tunkillia Suite
  • A single Gawler Range Volcanics sample returned connected porosity of approximately 1.2% and very low gas permeability of approximately 0.01–0.04 millidarcies, identified as a potential seal rock candidate
  • The company is targeting a mid-2027 exploration drilling campaign, with results to inform target selection and farm-out discussions

CSIRO Study Hydrogen Detection Results

The CSIRO study used a rock crushing technique to release gases trapped in fluid inclusions across 28 successfully analysed samples, detecting hydrogen in every sample. The results are described in the filing as consistent with hydrogen-bearing fluids having circulated through different basement rock units in the past. The filing states that the timing of circulation is unconstrained and that the findings do not demonstrate a present-day free-gas accumulation or indicate the volume of hydrogen potentially recoverable. CSIRO also identified faults and fracture networks as possible migration pathways, with several higher hydrogen measurements occurring near intersections of major structures.

Potential Hydrogen Source Rock Characteristics

CSIRO identified uranium and thorium enriched felsic rocks of the Hiltaba Suite, particularly the Cultana Subsuite, as leading candidates for radiolytic hydrogen generation. Investigated Cultana samples recorded uranium concentrations up to 50.9 parts per million and thorium up to 142.5 parts per million. A second potential generation mechanism involves oxidation of reduced iron during reactions between water and iron-bearing rocks. The Sleaford Complex chlorite schist contained 8.39% Fe²⁺ by weight, with additional reduced-iron potential identified in Tunkillia dolerites and Hiltaba-associated metagabbros. The study did not quantify present-day generation rates.

Next Steps Within Permit PEL 803

Prominence disclosed it will use the study results to refine the ranking of exploration prospects within PEL 803, with an emphasis on identifying areas where favourable potential source rocks coincide with fault or fracture pathways and credible reservoir and seal configurations. Follow-up work under consideration includes further assessment of hydrogen generation potential and distribution of enriched source rocks, expanded testing of volcanic cover and other prospective sealing units, and geological and geophysical review of their extent and integrity. The filing notes the results do not establish current hydrogen generation rates, a subsurface hydrogen accumulation, or commercial recoverability.