Announcement • Jul 13
Cobra Resources PLC Provides Manna Hill Drilling Update
Cobra Resources PLC has exercised its option to acquire Manna Hill. Cobra is providing an update on observations from the latest four-hole, 1,465m programme of diamond core drilling at the Manna Hill Copper Project, which has concluded. This programme phase was designed to test for extensions of the shallow, high-grade copper-gold mineralisation recently discovered at the Blue Rose prospect, while also evaluating the potential for a deeper intrusive-related porphyry copper system. Drill hole MHDD002 was drilled to test the depth continuity of shallow, high-grade RC intersections of 74m @ 1.02% Cu, 0.25g/t Au from 72m and 86m @ 0.60% Cu, 0.14 g/t Au from 18m. Multiple zones of chalcopyrite have been observed downhole from 169m to 209m, which is broadly consistent with sulphide quantities observed in RC drilling. Zones of bornite mineralisation are present from 220-257m 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. Chalcopyrite is present in biotite schists and calc-silicate skarn lithologies to the end of hole at 321m. Bornite mineralisation proximal to the porphyry intrusions coincides with an inversion modelled magnetic anomaly, providing a direct correlation between geophysics and mineralisation. This provides a direct targeting method for additional porphyry-type mineralisation. Geological findings refine targeting for follow-up RC drilling, which will test other key magnetic targets and skarn extensions. Drill hole MHDD001 intersected large alteration zones with a potassic alteration zone from 265m to 320m containing zones of significant pyrite and pyrrhotite and minor chalcopyrite, supporting proximity to a large porphyry body. Drill hole MHDD004 intersected shallow copper oxide mineralisation from 14-67.5m outside of the current modelled skarn footprint. Multiple mineralised intervals extend the depth of known skarn mineralisation. Magnetite and chalcopyrite mineralisation increase with depth, whilst observed garnet supports an increasing temperature gradient (closing proximity to an intrusive heat source). Chalcopyrite ± pyrite ± magnetite mineralisation observed at the following downhole intervals: 5m from 74m, 10m from 94.5m, 4m from 115m, 13m from 150m, 16m from 169m, 21m from 206m, 40m from 232m, 9m from 291m, 4m from 316m and 3m from 342m. Drill hole MHDD003 intersected a large fault-bound anhydrite breccia zone (190m to 220m). This is indicative of the sulphate, oxidising fluids of a porphyry system. The breccia is interpreted as a key structural pathway linking the parent porphyry to the Blue Rose skarn. Due to the strong oxidising nature of the fluids, such breccias do not contain sulphides but are an integral vector for modelling a porphyry system. Anhydrite breccias of this scale are unusual, but are a positive indication of a large porphyry system. Assay results anticipated from August. Visual estimates of mineral abundance should never be considered a proxy or substitute for laboratory analyses where concentrations or grades are the factor of principal economic interest. Visual estimates also potentially provide no information regarding impurities or deleterious physical properties relevant to valuations. A summary log of visual estimates of mineralisation for drill holes MHDD001 - MHDD004 is provided in Table 1 below. Diamond drilling was undertaken at the Manna Hill project to advance the geological understanding of copper-gold-molybdenum mineralisation within a calc-silicate skarn and a larger porphyry system. Skarn mineralisation is associated with a dolomite unit where the distribution of grade is associated with the proximity to porphyry pencil intrusions. Drilling demonstrates important geological indicators of a fertile porphyry system: Bornite mineralisation within strong potassic alteration (biotite and K-feldspar) indicates higher temperature formation. Mineralisation within MHDD002 spatially coincides with an E-W striking magnetic feature, which provides a proxy to determine further high-grade shoots. Multiple magnetic features coincide with modelled calc-silicates (skarn). Mineralisation assemblages within MHDD004 indicate increasing temperature, with the hole possibly approaching a heat source. The presence of a significant anhydrite breccia is a key feature of many porphyry systems and represents a fluid pathway for the migration of copper-bearing fluids into the overlying skarn. Core is currently being sampled for assay, with sections being prepared for petrology. The Company will incorporate findings into the design of follow-up RC drilling aimed at extending scale and step-out targets. The project is comprised of multiple early-stage porphyry and skarn prospects. The project also includes the Luron Carlin style gold prospect and multiple historic goldfields where over 30koz Au were reported to have been produced. This style of mineralisation remains underexplored and highly prospective. The project sits along the national railway and Barrier Highway between the mining hub of Broken Hill, the port and base metals smelter at Port Pirie and the City of Adelaide. Information in this announcement relates to exploration results that have been reported in the following announcements: Option to Acquire Significant Copper Project, 26 August 2025. Manna Hill: Further High-Grade Copper Results Support Scale, 14 April 2026. Manna Hill: Outstanding Copper Results Elevate Blue Rose from Prospect to Discovery, 9 March 2026. Manna Hill Exploration Update: IP survey results validate and extend copper-gold skarn and porphyry signatures, 8 January 2026. Option to Acquire Significant Copper Project, 26 August 2025. Information in this announcement has been compiled based on reports from Mitre Geophysics consultants and assessed by Mr. Rupert Verco, a Fellow of the Australasian Institute of Mining and Metallurgy. Mr. Verco is an employee of Cobra and has more than 18 years' industry experience which is relevant to the style of mineralisation, deposit type, and activity which he is undertaking to qualify as a Competent Person as defined in the 2012 Edition of the Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves of JORC. This includes 13 years of Mining, Resource Estimation and Exploration. Mr. Verco consents to the inclusion in this announcement of the matters based on his information in the form and context in which it appears.
