Greenvale Energy Finds Six New Uranium Targets and Fault Link at Thunderball

Greenvale identifies six new uranium targets at Thunderball as field teams confirm fault splay link to high-grade deposit

Greenvale Energy (ASX: GRV) has completed a project-wide geophysical review at the Thunderball Uranium Project in the Northern Territory, yielding six confirmed new drill targets within EL33670 (southern tenement), complementing ongoing fieldwork on EL34157. Field teams have also confirmed a newly interpreted fault splay with a structural connection to the Hayes Creek Fault, the same system associated with high-grade uranium deposits including the Thunderball deposit.

Q1 FY27 fieldwork snapshot: what Greenvale’s teams found on the ground

Arrow Geoscience completed an independent review of publicly available and company-procured geophysical data, merging airborne magnetics, radiometrics, gravity, and electromagnetics datasets sourced from the Northern Territory Geological Survey (NTGS) alongside Greenvale’s own 2024–2025 Airborne Magnetics-Radiometrics (AMR) surveys.

The review identified a major NW-SE trending fault structure within the central portion of EL33670. This structure is significant because it may represent a potential graben — a block of crust dropped by faulting during basin formation — which can create space for uranium-rich fluids to enter the overlying sediments from the bedrock below. Airborne radiometric anomalies were identified on the north-eastern side of the interpreted fault, showing good correlation with coincident magnetic anomalies.

Greenvale’s field team ground-truthed these geophysical results, confirming six new targets within EL33670:

• DR15
• DR16
• DR17
• DR21
• DR23
• DR24

All six targets showed consistent high anomalism, with readings up to 17ppm eU against a natural background of approximately ~4ppm eU. Geologically, these anomalies coincide with mapped limestones and minor granite outcrops, though surface exposure was infrequent. Field investigations in the area are continuing.

Chemical assay results validate field readings at three prospects

Initial independent geochemical assay results have confirmed uranium anomalism at the Powers, Wildcard South, and Spectre Prospects.

Greenvale’s uranium discovery at Oasis demonstrated the company’s capacity to convert field anomalies into confirmed mineralisation, a progression that the Thunderball program is now replicating through chemical assay validation at Wildcard South, Powers, and Spectre.

At Wildcard South, peak results reached up to 51ppm U, with chemical assay results showing consistent correlation with RS-125 and pXRF field readings. At the Powers Prospect, results are considered anomalous given background values of only 3ppm U. The lack of outcrop at Powers is a strong indicator of a thicker package of cover sediments, which warrants further investigation of the prospect area.

At Spectre, chemical assay confirmed uranium mineralisation up to 21ppm U from the first breccia outcrop discovered in July 2026, with corresponding RS-125 and pXRF readings of 27ppm eU and 21ppm U respectively.

Note that RS-125 and pXRF readings cited in this release are qualitative spot measurements and should not be considered equivalent to laboratory assay results. pXRF and RS-125 values are subject to variability due to sample heterogeneity, surface effects, and instrument limitations, and are intended only as an indication of elemental presence and relative abundance. Definitive results are confirmed through independent laboratory chemical assay.

The Spectre fault splay — why this structural discovery matters

The Hayes Creek Fault is a major NE-SW trending structural system associated with high-grade uranium deposits such as the Thunderball deposit. Fault splays are smaller-scale faults that branch off the main fault system on a NNE-SSW orientation, eventually intersecting back into the main structure.

These splays are significant because they create openings in the polymetallic rocks of the Pine Creek Orogen, acting as large-scale transport pathways for uranium-bearing fluids to enter the overlying, younger basin sediments. Identifying a new splay is meaningful because it defines a new structural corridor where uranium mineralisation may have accumulated, ahead of any drill testing.

Two breccia outcrops, one compelling corridor

Two separate breccia outcrop discoveries have defined this newly interpreted fault splay:

In July 2026, field teams discovered the first outcrop of breccia approximately 1.1km south-east of the Spectre Prospect. RS-125 and pXRF readings of 27ppm eU and 21ppm U respectively strongly indicated uranium anomalism, and chemical assay subsequently confirmed uranium mineralisation with values up to 21ppm U.

In September 2026, a second outcrop of breccia was discovered to the north-northeast of the first. RS-125 and pXRF results again indicated uranium anomalism, with maximum readings of 9.9ppm eU and 39ppm eU respectively. Independent assays from this second outcrop are pending.

Both outcrops are interpreted as part of a fault splay coming into the main Hayes Creek Fault, with the point of intersection situated approximately 1.5km east of the Spectre Prospect. Multiple anomalous outcrops along the same structure define a clearly delineated exploration corridor ahead of drill testing.

Alex Cheeseman, Managing Director

“The Greenvale field team is successfully expanding our exploration target pipeline across the entire land package, which is an excellent result.”

What comes next for Greenvale’s Thunderball exploration program

Greenvale is systematically building a target inventory across its Northern Territory land package ahead of a potential drilling campaign, with the Thunderball Project now generating activity across two exploration licences. The near-term pipeline includes:

Greenvale’s Northern Territory uranium exploration program spans multiple tenements and geological settings, with the Thunderball Project representing one component of a broader land package the company has been systematically advancing through geophysical review and ground-truthing campaigns.

1. Field investigation of remaining radiometric anomalies is continuing across both EL33670 and EL34157, with the aim of testing as many areas as possible before the Wet Season build-up
2. Permitting and approvals are progressing for identified prospects to allow flexibility to undertake initial drill testing across a range of targets
3. Additional geochemical assay results are pending across multiple targets (a number of Appendix 1 results remain TBC at time of this announcement)
4. New fieldwork is planned at the Elkedra-Henbury Project, involving similar geological mapping, RS-125/pXRF assessment, and physical sample collection

The table below summarises confirmed prospects with key assay results from the announcement narrative. Appendix 1 entries listed as “TBC” have not been included.

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