Summary

Mine Type	Underground
Status	Active
Commodities	Gold
Mining Method	Longhole open stoping Sub-level open stoping (SLOS)
Backfill type	...
Production Start	...
Mine Life	...
Snapshot	The Thunderbox UG operation forms part of the Thunderbox & Bronzewing operations and includes the Thunderbox underground mine and the Wonder underground deposit. Mining at the Wonder underground mine commenced in November 2023. Thunderbox achieved record underground ore tonnes mined in Q4 FY2025.

Deposit type

• Vein / narrow vein
• Mesothermal

Summary:

Thunderbox deposit
Thunderbox is a mesothermal lode gold deposit located at the southern end of the Yandal greenstone belt in an area where several major shear zones converge and join with the Perseverance Fault.

The shear zone dips at 30° to 60° WSW, with the exception in the vicinity of the mineralisation, where the shear is vertical to steeply dipping. Mineralisation is hosted by strongly deformed, silicified and carbonate altered albite-quartz porphyry in the hangingwall of the shear zone. The shear juxtaposes foliated basalts and intrusive porphyries in the hanging wall against sedimentary rocks in the footwall. The zone of shearing is over 200 m wide. An ultramafic unit occurs within the shear in the footwall of the deposit and is attenuated along the shear.

The main gold related hydrothermal alteration assemblage comprises quartz-ankerite-arsenopyrite-pyrrhotite-galena and gold. This assemblage has been overprinted by a retrograde chlorite-epidote-white mica-biotite-quartz and pyrite assemblage. Syn-mineralisation veins have a continuum of vein textures ranging from laminated to pseudobreccias.

Throughout the Thunderbox Deposit, elevated grades occur within southerly plunging ore shoots that are more evident in the lateral extents of the orebody. Whilst the shoots persist centrally, the gold distribution is more uniform and ubiquitous than in other areas.

Dimensions
Thunderbox mineralisation extends from 6879000 mN to 6881000 mN, 304000 mE to 304400 mE and 500 meters below surface (MGA-Zone51).

The Thunderbox shear generally strikes NNW and dips 60° towards the WSW. Near the strongest gold mineralisation the shear is vertical to steeply west dipping.

The shear and mineralisation is offset across a series of dextral, NE trending faults.

Wonder deposit
The Golden Wonder mineralisation is situated within 6862220 mN to 6862960 mN, and 322620 mE to 323700 mE and from 500 mRL to -150 mRL below surface. The mineralisation has a strike length of 1.15km and approximately 0.5km down dip extent at Wonder North. Planned widths vary locally from <1 m up to 30 m, but predominantly 5-15 m.

Mining Methods

- subscription is required.

Comminution

Crushers and Mills

Processing

- subscription is required.

Commodity Production

Commodity	Units	2025	2024	2023	2022	2021	2020	2019
Gold	oz	....	....	....	....	....	....	9,542

Operational metrics

Metrics	2025	2024	2023	2022	2021	2020	2019
Ore tonnes mined	....	....	....	....	....	....	126,171 t
Waste	....	....	....	....	....	....	199,081 t

Personnel

Job Title	Name	Profile	Ref. Date
.......................	.......................		Aug 29, 2025
.......................	.......................		Aug 29, 2025
.......................	.......................		Aug 29, 2025
.......................	.......................		Aug 29, 2025
.......................	.......................		Aug 29, 2025