Mamba Reframes Copper Hills as Priority Sediment-Hosted Copper Target at Meeka East
Mamba reframes Copper Hills as priority sediment-hosted copper target at Meeka East
Mamba Exploration (ASX:M24) has completed an internal reappraisal of historical data at the Copper Hills prospect (E51/1716), identifying potential for sediment-hosted (SEDEX / VSHMS-style) copper mineralisation. The new interpretation reframes Copper Hills as a Whim Creek / Mons Cupri-style system in the Yaloginda Formation — differing from the previously targeted intrusion-hosted VMS model.
The review was prompted by renewed regional interest, including Solstice Minerals (ASX:SLS) activity at its Nanadie Copper-Gold Project. An additional exploration licence application has been lodged over ground to the north of existing tenure.
This is a reinterpretation of existing data, not a new discovery. The copper assessment complements — and is separate from — the primary Meeka East gold program.
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A history of high-grade copper in the ground
Documented historic copper production establishes that Copper Hills hosts an active copper-bearing hydrothermal system. In the 1950s, narrow high-grade veins in the “Lady Alma Intrusive” area were worked to recover approximately 971 tonnes at 7.1% Cu, sold as an agricultural copper additive. While these workings were narrow and do not indicate bulk tonnage, they confirm the presence of copper mineralisation.
The historic Gabanintha Mine, located within the same broader tenure, produced both copper and gold, consistent with the sediment-hosted hydrothermal model now being applied.
Lion Rock Minerals (ASX:LRM) — previously named Peak Minerals (ASX:PUA) — completed diamond drilling at Copper Hills in 2022 as part of a VMS and intrusion-hosted base metals program. The highest-grade copper intersections reported were:
- 0.13m at 4.95% Cu from 827.87m
- 0.20m at 4.18% Cu from 899.15m
Five separate copper intersections were reported in the felsic sequence in the upper ~600m of the two diamond holes, averaging 0.44m at 0.78% Cu and 1.3% S.
| Source/Program | Interval | Grade | Depth/Notes |
|---|---|---|---|
| 1950s Lady Alma Mining | ~971 tonnes | 7.1% Cu | Narrow high-grade veins, sold as agricultural additive |
| Lion Rock 2022 Diamond Drilling | 0.13m | 4.95% Cu | From 827.87m |
| Lion Rock 2022 Diamond Drilling | 0.20m | 4.18% Cu | From 899.15m |
| Lion Rock 2022 (5 intersections) | Avg 0.44m | 0.78% Cu, 1.3% S | Felsic sequence, upper ~600m |
What “sediment-hosted copper” means — and why the new model matters
Under the previous VMS targeting model, the narrow copper veins at Copper Hills were interpreted as peripheral to a possible larger intrusive-related body. Mamba’s revised interpretation positions these veins within the felsic volcano-sedimentary sequence of the Yaloginda Formation / Norrie Group — the primary target host for a Whim Creek-style system.
A sediment-hosted (SEDEX) copper system forms when hot, metal-rich fluids move through sedimentary rock layers and deposit copper (and often zinc or lead) in concentrated zones. These systems typically occur in broad, layered formations rather than narrow veins associated with igneous intrusions.
Under Mamba’s revised model, the narrow copper veins observed in drilling may represent “vein-style leakage” from a larger stratabound system beneath — a fundamentally larger target style than narrow veins alone. A stratabound system is one where mineralisation is confined to specific rock layers, potentially extending over significant distances along the geological horizon.
This reframing changes the prospectivity profile, though the larger system remains unproven pending further work.
Key technical observations supporting the revised interpretation include:
- Copper and sulphur are strongly correlated in high-magnesian basalt (10–17% MgO, 300–1,000 ppm Cr), a setting comparable to interflow sediments hosting nickel mineralisation at many WA nickel mines.
- A single 0.7% Ni assay coincides with a 13cm sulphide vein carrying 5% Cu.
- The felsic–HMB contact coincides with the copper veining zone — providing a testable stratigraphic control.
- The geology is analogous to Whim Creek / Mons Cupri Cu-Pb-Zn systems in the Pilbara.
The regional angle — sitting in Solstice’s copper corridor
Copper Hills sits in the same geological corridor as Solstice Minerals’ Nanadie Copper-Gold Project. Mamba’s interpretation suggests the Nanadie greenstone may once have been joined to Copper Hills stratigraphy, now separated by later granite intrusion — a configuration not unusual in the Youanmi Terrane.
Solstice’s 26 June 2026 announcement of “Exceptional Wide Copper-Gold Intercepts in First Diamond Hole at Nanadie” has renewed regional copper exploration interest. Mamba’s reappraisal positions the company in a region attracting fresh attention for sediment-hosted copper potential.
Matt Freedman, Executive Director
“The reappraisal points to the potential of a sediment-hosted copper system at Copper Hills, a target style not previously tested on the tenure. A low-cost program of relogging, mapping and geophysical reinterpretation will determine whether dedicated exploration is warranted. While we undertake this work, we continue to prepare to drill at the Meeka East Gold Project, which we look forward to commencing as soon as possible following heritage and regulatory approvals.”
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Next steps and what’s ahead
Mamba has outlined a low-cost work program to determine whether dedicated copper exploration at Copper Hills is warranted. The program is designed to validate the sediment-hosted model and generate drill targets. Critically, this copper work is separate from — and does not delay — the Meeka East gold drilling program.
The Copper Hills work program includes:
- Relogging of Lion Rock diamond core against the new stratigraphic framework and rock classification.
- Detailed geological mapping in conjunction with the GSWA.
- Rock-chip sampling incorporating a Cu-P pathfinder program — a technique previously applied at Nifty Copper and by the author at Bulloo Downs.
- Reinterpretation of existing magnetic, gravity and EM datasets under the sediment-hosted model.
- Generation of drill targets for a future dedicated copper program.
Timing of any follow-up drilling at Copper Hills will be determined by the outcome of the work program.
Meeka East Gold Project remains on schedule:
- Yugunga-Nya heritage survey is scheduled for the end of July.
- RC drilling is planned to commence following heritage clearance and regulatory approvals.
- Mamba holds a 70% interest in the flagship Meeka East Gold Project.
The Copper Hills reappraisal adds an optional, low-cost copper dimension to a company whose primary focus remains gold. No drilling results have been announced under the new model — this is target generation and geological reinterpretation pending further work.
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