Summary:
The Binduli Project includes two areas: Binduli South District and the Binduli North District. The Binduli South District comprises four deposits and the Binduli North District consists of six gold deposits. Of these ten gold deposits, the Navajo Chief, Centurion, Ben Hur, Apache and Janet Ivy deposits have the most resources of the Binduli Project.
Navajo Chief Deposit
The Navajo Chief deposit lies at the northwest end of the NC-BE-CT-BH mineralized trend. The mineralisation is primarily hosted within sodic-altered siltstone and sandstone, with kaolin-rich zones interpreted as weathered sodic-altered siltstones, particularly in the southern part of the pit. Throughout the deposit, higher gold grades typically occur in the transitional zone between weathered and fresh rock, indicating significant supergene enrichment.
Primary mineralisation is strongly associated with sodic alteration zones, which also host some quartz-carbonate (-pyrite-tourmaline) veins. However, selective sampling has shown that the highest gold grades (5–8 g/t Au) are generally found in zones devoid of quartz veins, while quartz veins themselves return low grades (<0.27 g/t Au), suggesting they are not the primary carriers of economic gold.
Structurally, the deposit exhibits only a few brittle-ductile faults. In the centre of the pit, a fault striking 80° contains quartz veins at depth, but not on the pit walls. The north pit hosts steeply oriented quartz veins unrelated to the shallow-dipping sets seen elsewhere. On the west wall, quartz veins spaced by several metres are hosted in greywacke and white kaolin units, while in the east, quartz-carbonate alteration extends into siltstones.
Overall, the deposit’s main mineralised contributions are from sodic-altered host rocks, with gold and pyrite often depleted in brittle-ductile fault zones. Hydrothermal activity and mineralisation appear largely unrelated to significant fault conduits, suggesting mineralisation likely migrated through more diffuse pathways.
Janet Ivy Deposit
Janet Ivy is hosted in a large rhyodacitic porphyry intrusion (~2.5 km long and up to 150 m wide), faulted and sheared along its margins. The weathering profile reaches depths of 50–60 m and includes clay-saprolite and lateritic zones.
Gold mineralisation is associated with quartz veins (millimetres to 40 cm wide) containing minor sulphides (mainly pyrite), which occur in both potassic and carbonate alteration zones, though they are more abundant in the potassic zone. Veins often have sodic or muscovite alteration halos. Vein types range from massive quartz to breccia and fibrous textures.
Veins are primarily extensional and oblique, with dominant orientations dipping 35° toward 019°, 80° toward 342°, and a minor maximum at 55° toward 170°. Quartz fibre orientations indicate a shallow NNW-SSE extensional regime. Mineralisation (>0.5 g/t Au) forms a NNW-trending zone along the western margin of the porphyry, extending into faults on either side.
High-grade gold (>1.5 g/t Au) occurs sporadically, especially near the Western and Eastern Splay Faults. The mineralisation envelope extends beyond the potassic zone into carbonate-altered rock. Selective sampling of quartz veins with pyritic sodic alteration halos (results pending) is presumed to confirm the veins and their halos as the primary source of gold.
Ben Hur Deposit
Located in the footwall of the Centurion Fault, the Ben Hur deposit comprises porphyry breccias, folded porphyries, and epiclastic sediments. The felsic porphyry intrudes along anticlines and exhibits westward dips of 50–80°. The east side consists of steeply dipping black shales and feldspar-rich volcanics.
Gold is hosted in shallow west-dipping veins developed in hematite-magnetite altered feldspar-quartz porphyry, which becomes clay-decomposed in the upper weathering zone. A 20–30 m thick leached cap covers supergene gold, which typically overlies primary zones, creating a mushroom-shaped mineralisation geometry. Multiple supergene fronts with moderate dispersion suggest influence from fluctuating water tables.
Primary gold mineralisation occurs in steep, west-oriented veins (~340°), inferred to wedge between the Centurion Fault and sheared carbonaceous shales. Alteration includes hematite, pyrite, carbonate, and sericite.
Apache Deposit
Apache is located east of Navajo Chief and is structurally controlled by the west-dipping Abattoir Fault, which separates the Binduli and Kalgoorlie greenstone belts. The local geology comprises metamorphic sediments intruded by quartz-feldspar porphyry.
Gold mineralisation occurs within a weak quartz vein stockwork, associated with strong bleaching, silicification, and disseminated pyrite. Veins average 1 cm in width and occur at 1–2 veins per metre. The mineralised body exhibits a shallow eastward dip (<30°) with a slight southward plunge, sub-parallel to the BOCO horizon. Mineralisation is controlled by both NE- and NW-trending faults.
Centurion Deposit
The Centurion deposit lies within volcanosedimentary units and features two main styles of mineralisation:
- Eastern Contact Mineralisation (ECM): High-grade, pyrite-quartz-rich zone adjacent to a black shale contact, between 4920N and 5040N. It plunges 20°–45°N, following the hinge of the Centurion antiform. Mineralisation likely formed via fluid flow along the Centurion Shear and porphyry flanks, resulting in gold-silica-sericite-pyrite alteration. The gold is hosted in a wedge of fine sediments potentially intruded by a porphyry cryptodome and associated breccia.
- Western Contact Mineralisation (WCM): Associated with similar lithologies and structural controls, but with less detailed description.
Both styles are linked to significant hematite-magnetite alteration, forming strong geophysical signatures. Areas of albite-silica-sericite-pyrite alteration within these magnetic zones result in magnetically destructive signatures, aiding in exploration targeting.