The Sovereign Project is located in the highly prospective Julimar region of Western Australia, ~70km north-east of Perth. At the Sovereign Project, DevEx is exploring a large, 12km long mafic-ultramafic intrusion complex for nickel, copper and platinum group elements (Ni-Cu-PGE) along strike from the globally significant Julimar Ni-Cu-PGE discovery to the south and the Yarawindah Brook Ni-Cu-PGE project to the north, owned by Chalice Mining Ltd (ASX: CHN) and by Caspin Resources Ltd (ASX: CPN) respectively (Figure 1).
Figure 1: DevEx Tenement together with the Australian Silica Quartz Group Ltd (ASQ) Tenement overlying airborne magnetics (RTP) in relation to Chalice Mining Limited’s high-grade palladium-nickel discovery (ASX: CHN) at the Julimar Project. The outline of the Julimar Complex was interpreted by the Company from information in Harrison (1984).
DevEx is currently exploring the western half of the Sovereign mafic-ultramafic Intrusion (E70/3405) under an Earn-In Agreement with Australian Silica Quartz Group Ltd (ASX: ASQ). The eastern half of the intrusion is located within a granted tenement held by DevEx (E70/5365) – see Figure 1.
Reconnaissance air-core (AC) drilling has continued to map the extensive differentiated mafic-ultramafic intrusion within the Sovereign Project, with 318 holes for 8,346m extending the strike of the intrusion to at least 12km in length, with several windows of underlying metamorphosed pyroxenite and mela-gabbronorite rimmed by elevated palladium and platinum.
DevEx’s maiden stratigraphic diamond drilling program was designed to test the central portion of the Sovereign mafic-ultramafic intrusion, providing information on the geometry and geology of the intrusion.
Two diamond holes (Holes 1 and 2), collared 550m apart, were designed to provide information on the geometry and geology of the intrusion at depth within the central portion of the Sovereign mafic-ultramafic intrusion.
Within Hole 2 (Figure 2), broad intervals of low-grade disseminated nickel-copper sulphide mineralisation are observed in the hole, including several narrow (5-10cm) bands of matrix textured iron-nickel-copper sulphides.
Assay results from Holes 1 and 2 have confirmed these zones of low-grade disseminated Ni and Cu sulphide mineralisation within the gabbronorite-norite and pyroxenite rocks (see Figure 2), in line with visual observations of the diamond drill core.
Figure 2: Matrix textured Fe-Ni-Cu sulphides within norite rock at 431.4m down-hole in Hole 2 (left) and disseminated Ni-Cu-Fe sulphides within norite rocks at 232.3m down-hole in Hole 2 (right).
A third diamond hole (Hole 3), drilled 3.5km to the north of Hole 2 with co-funding assistance from the WA Exploration Incentive Scheme (EIS), has also intersected a thick sequence of moderately west dipping mafic-ultramafic intrusive rocks to the bottom of the hole (586m). Preliminary observations of the core have identified a narrow (one metre) zone of minor disseminated Fe-Ni-Cu sulphides within a pyroxenite.
An extensive ground EM survey has commenced and is designed to test for conductors associated with Ni-Cu-PGE mineralisation within the 12km-long Sovereign Mafic-Ultramafic Intrusion. Although the Fe-Ni-Cu sulphides seen in Hole 2 are only weakly conductive with no immediate off-hole response, the potential for a massive sulphide accumulation along strike from these disseminated sulphide zones provides a focus for the ground EM.
Figure 3: Sovereign Project: Location of three diamond drill holes 21SVDD01 (Hole 1) - 21SVDD03 (Hole 3), drilled to understand the local geology and framework of the mafic ultramafic intrusion. Local grid provided for context to Figure 4.
Figure 4: Generalised geological cross-section and interpretation with nickel and copper assays represented as histograms (Oblique to GDA Grid – temporary local grid provided – see Figure 3) showing the distribution of low-grade disseminated Ni-Cu sulphide mineralisation within and at the base of the mafic-ultramafic intrusion. The shallowing position of these zones provides a focus for ground-based EM in January 2022.