Announcement • Apr 14
Cobra Resources plc Reports Further High-Grade Copper Results At Manna Hill Project
Cobra Resources plc reported results from a further 12 reverse circulation ("RC") drillholes from the Blue Rose copper-gold-molybdenum discovery and associated targets within the Manna Hill Copper Project, located in the Nackara Arc, South Australia. Additional high-grade, broad and shallow sulphide mineralisation adds to the scale potential at Blue Rose. New results include MHRC0013: 62m at 1.0% Cu, 0.08 g/t Au from 62m, including 30m at 1.56% Cu, 0.14 g/t Au from 66m, including 16m at 1.92% Cu, 0.23 g/t Au from 74m; MHRC0011: 22m at 0.80% Cu from 20m, including 6m at 1.56% Cu from 22m; MHRC0009: 22m at 0.48% Cu, 0.17 g/t Au from 30m, including 10m at 0.81% Cu, 0.37 g/t Au from 30m; MHRC0010: 6m at 0.77% Cu from 24m, including 2m at 1.56% Cu from 26m and 4m at 0.073% Mo from 94m. Results build upon earlier results that included MHRC0018: 20m at 0.78% Cu, 0.14 g/t Au from 38m, and 74m at 1.02% Cu, 0.25 g/t Au from 70m; MHRC0017: 86m at 0.60% Cu, 0.14 g/t Au from 18m; MHRC0003: 56m at 0.34% Cu from 34m, including 18m at 0.52% Cu from 38m, and 14m at 0.21% Cu, 0.01% Mo from 122m, and 10m at 0.12% Mo from 144m. Geochemical analysis, metal zonation and structural interpretation support targeting a central IP resistive plug as the primary porphyry target, located directly underneath the Blue Rose skarn, proximal to recent molybdenum intersections associated with porphyry-type quartz monzonite intrusive. In a local geological context, resistivity is interpreted to reflect silicification; hydrous alteration that would occur within proximity to an intrusion (porphyry heat source). Molybdenite forms at higher temperatures in porphyry systems and is therefore an effective geochemical marker for potassic zone, porphyry mineralisation. A diamond drill rig is booked for late April, with work commencing to re-establish site access shortly. Diamond drilling will target depth extensions beneath defined high-grade intersections and shall investigate the central resistive zone. Cobra has recently announced its intention to exercise its option to acquire the Manna Hill Project ("Manna Hill Option") based on the drilling results received to date. Under the Manna Hill Option agreement, Cobra sought to test several geological observations that have implications for a large-scale mineral system at Blue Rose. This included testing for the continuity of Blue Rose skarn mineralisation at both depth and strike extent. Results demonstrate considerable opportunity for increasing scale with broad zones of primary sulphide mineralisation being intersected outside of the extent of previous drilling. Results received to date demonstrate confirmation of economic widths extending at depth into primary sulphide mineralisation. Mineralisation intersected within MHRC0013 and MHRC0018 commence in transitional mineralisation and continue into primary sulphides, where copper speciation is predominantly chalcopyrite. This supports mineralisation continuity with depth. MHRC0013 has intersected 62m at 1.0% Cu from 62m at the western most extent of previously identified shallow oxide mineralisation. MHRC0013 is 750m west of the previously reported MHRC0018 which intersected 20m at 0.78% Cu, 0.14 g/t Au from 38m and 74m at 1.02% Cu, 0.25g/t Au from 70m. Mineralisation remains open west of MHRC0013. Mineralisation is expected to extend with depth east of MHRC0018 where historical drilling has intersected shallow oxide mineralisation. Geochemistry indicates increased levels of potassic alteration that is spatially associated with intersections elevated in molybdenum within drillholes MHRC001,003 and 008. Molybdenum mineralisation is associated with quartz monzonite and diorite porphyry type dykes. These drillholes intersect skarn mineralisation directly above a resistivity IP anomaly. The resistivity anomaly >150 ohms is interpreted to reflect silicification of the host rock, a likely outcome of porphyry alteration. The deepest historic drillholes BRDD003 (26.7m at 0.43% Cu from 195m) and RCBR035D (23.25m at 0.22% Cu from 276.25m) end in low grade mineralisation and are closest in proximity to the IP resistivity target. Cobra is currently designing a follow-up diamond programme to test the IP resistivity anomaly. Two significant zones of high grade >1% Cu have been intersected within primary sulphide mineralisation. Mineralisation remains open at depth and along strike. Subsequent diamond drilling will target mineralisation below drillholes MHRC0013 and MHRC0018. Depth extensions and along strike continuity defined within these zones will significantly increase the metal potential of the Blue Rose skarn. Geochemical and metal zonation indicate increased temperature and subsequent potassic alteration proximal to the IP resistivity anomaly. Molybdenum is generally associated with higher temperature or more potassic zones of a porphyry system and therefore the intersection within MHRC0003 of 10m at 0.12% Mo from 144m, including 2m at 0.38% Mo from 146m is high grade molybdenite. This drillhole has increased potassic alteration. Historical diamond drillhole BRDD003 intersected 26.7m at 0.43% Cu from 195m and RCBR035D intersected 23.25m at 0.22% Cu from 276.25m. Both holes were terminated in copper mineralisation, which based on core photographs does not appear to be skarn hosted. These two intersections are within the closest proximity to the IP resistivity anomaly. These geological observations provide sufficient evidence to test the IP resistivity anomaly with a third diamond drillhole.
