Bornite-Rich Zone Tied to Porphyry Intrusions Adds Scale to Manna Hill as Cobra Exercises Acquisition Option

• A concluded four-hole, 1,465-metre diamond drilling programme at the Manna Hill Copper Project tested extensions of the shallow, high-grade Blue Rose mineralisation and the deeper porphyry potential.
• Drilling intersected a bornite-rich zone from 220 to 257 metres depth, associated with porphyry diorite and monzonite intrusions and indicating higher-temperature formation.
• The bornite zone coincides with an inversion-modelled magnetic anomaly, providing a direct correlation between geophysics and mineralisation to guide targeting of further porphyry-type mineralisation.
• Observed sulphide mineralisation now extends to a depth of 300 metres within a high-grade portion of the existing footprint.
• Cobra has formally exercised its option to acquire Manna Hill and is progressing two South Australian projects in parallel. 
• Assay results are targeted from August 2026, with follow-up reverse-circulation drilling planned for September 2026.

Company Overview

Cobra Resources (LSE: COBR) is a South Australian critical minerals developer advancing assets across all stages of the pre-production pathway. In 2023, the company identified the Boland ionic rare earth discovery at its Wudinna Project in the Gawler Craton, described as Australia's only rare earth project suitable for in situ recovery (ISR) mining, a low-cost, low-disturbance method that removes the need for excavation. In 2025, it optioned the Manna Hill Copper Project in the Nackara Arc and sold its Wudinna Gold Assets to Barton Gold for up to A$15 million in cash and shares.

The Manna Hill Drilling Programme 

The concluded programme comprised four holes of diamond core drilling totalling 1,465 metres, designed to test extensions of the shallow, high-grade copper-gold mineralisation recently discovered at the Blue Rose prospect and to evaluate the potential for a deeper intrusive-related porphyry copper system. The flagship hole was drilled to test the depth continuity of earlier reverse-circulation (RC) intersections: 74 metres at 1.02% copper and 0.25 grams per tonne gold from 72 metres depth, and 86 metres at 0.60% copper and 0.14 grams per tonne gold from 18 metres depth.

Managing Director of Cobra Resources, Rupert Verco, is precise on the depth this programme reached:   

"This drilling has extended observed sulphide mineralisation to a depth of 300m within a high-grade portion of the existing footprint." 

Bornite & Porphyry Intersection 

The flagship hole intersected a bornite zone from 220 to 257 metres depth within a mineralised biotite schist that envelops porphyry diorite and monzonite intrusions. Bornite is a copper sulphide mineral with a high copper-to-iron ratio that forms at higher temperatures and is associated with potassic zones of porphyry systems. It sits within strong potassic alteration of biotite and potassium feldspar, indicating higher-temperature formation. Chalcopyrite was observed from 169 to 209 metres depth, broadly consistent with sulphide quantities seen in RC drilling, and continues in biotite schists and calc-silicate skarn lithologies to the end of the hole.      

Visual estimates place bornite at up to 2% across the zone, though they are neither a proxy for nor a substitute for laboratory analyses. 

Verco frames the bornite intersection this way: 

"Intersecting a bornite-rich zone associated with a porphyry intrusive sequence is a positive indicator of a potentially higher-grade porphyry system. The insights gained from this drilling are improving our understanding of the mineral system and the relationship between geophysics and mineralisation. As this relationship becomes clearer, further scalable targets are emerging."  

Geophysics & Mineralisation Correlation

The bornite mineralisation proximal to the porphyry intrusions coincides with an inversion-modelled magnetic anomaly, providing a direct correlation between geophysics and mineralisation and a direct targeting method for additional porphyry-type mineralisation. Mineralisation in the flagship hole spatially coincides with an east-west striking magnetic feature that acts as a proxy for determining further high-grade shoots. Multiple magnetic features coincide with modelled calc-silicate skarn, refining targeting for follow-up drilling of other key magnetic targets and skarn extensions. 

Corroborating Observations Across the Programme  

The remaining holes add further support for a large porphyry system. One hole intersected a potassic alteration zone from 265 to 320 metres depth containing significant pyrite and pyrrhotite with minor chalcopyrite, supporting proximity to a large porphyry body. A second intersected a large fault-bound anhydrite breccia zone from 190 to 220 metres depth, indicative of the sulphate, oxidising fluids of a porphyry system and interpreted as a key structural pathway linking the parent porphyry to the Blue Rose skarn. Anhydrite breccias of this scale are unusual but represent a positive indication of a large porphyry system, and although the oxidising fluids leave them free of sulphides, they remain an integral vector for modelling the system.    

A further hole intersected shallow copper oxide mineralisation from 14 to 67.5 metres depth, outside the current modelled skarn footprint, with multiple mineralised intervals extending the depth of known skarn mineralisation. In that hole, magnetite and chalcopyrite increase with depth, while observed garnet supports an increasing temperature gradient, consistent with the proximity to an intrusive heat source. Molybdenite was also recorded at depth within the same hole. 

Exercise of the Manna Hill Option  

On the strength of these observations, Cobra formally exercised its option to acquire Manna Hill, first set out in its August 2025 announcement. Blue Rose is held by Hamelin Gully Pty Ltd, and Cobra subsidiary Manna Hill Mining Pty Ltd exercised its option to acquire Hamelin Gully, with the exercise announced in July 2026. A 1% overriding royalty agreement is registered between Hamelin Gully and Springton Trust; a Native Title Agreement is in place between the Wilyakali People and Hamelin Gully; and cultural heritage surveys have been completed across the licence, clearing proposed drill sites. 

On the corporate step, Verco is direct:

"With strong shareholder support, we have exercised the Manna Hill Option and are now progressing two significant South Australian projects in parallel." 

Next Steps

Core is currently being sampled for assay, with sections prepared for petrology, and assay results are targeted from August 2026. The findings will be incorporated into the design of follow-up RC drilling to extend scale and step-out targets, planned for September 2026 at Blue Rose, Desert Rose, and Double Delight. Follow-up diamond drilling at Desert Rose and a greenfields soil sampling programme are also planned.  

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