The company’s Pinnacle Project is comprised of three exploration licenses (E37/1246, E37/1287, E37/1355 E37/1234 and E37/1235 and prospecting leases P37/9139 and P37/8573,) covering an area of 166 km2. The project is located approximately 25km north of Leonora adjacent to the Goldfields Highway.
The project is located in the Archaean aged Yilgarn Craton of Western Australia and lies within the Kurnalpi terrane of the Eastern Goldfields Superterrane. At a district scale, the Leonora area hosts numerous world-class gold deposits which include the Sons of Gwalia, King of the Hills, Thunderbox, Darlot and Agnew gold deposits. Base metal volcanogenic massive sulphide (VMS) deposits such as Teutonic Bore, Jaguar and Bentley are located nearby to the north.
The area is well structurally prepared being transected by the regionally significant Keith-Kilkenny Shear Zone and the Pig Well Graben – located in the southern portion of the tenements.
Locally, the project area Archaean bedrock geology is poorly exposed (only approximately 15% of the project area with exposure, predominantly to the north in granitoid lithologies) and presents largely as areas of moderate to intensely weathered subcrop and associated Quaternary colluvial and alluvial cover ranging from a few metres deep to tens of metres deep.
The syeno-granite of the Bundarra batholith dominates the northern portions of E37/1246 and E37/1234. The greenstone sequences to the south consist of a basalt and andesite-dacite dominated volcanic sequence with lesser rhyolite and felsic to intermediate composition intrusives.
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Sediments and conglomerates of the Pig Well Graben are located to south and a separate syenite granitoid intrusion is in the SW corner. The same east-west dolerite dyke that is associated with the Mt Davis mineralisation transects the leases.
Previous exploration has confirmed the presence of gold, base metal, and molybdenum mineralisation in numerous locations across the licenses. At least two significant but poorly tested gossans, striking several hundred metres, are located on the project area and are interpreted as having base metal potential. The western gossan lies near the Jaguar VMS trend and a second gossan, in the north-east, lies near a major zone of greisen development of the granite.
The lease area overall has had very limited drilling, despite the presence of a highly prospective greenstone belt, extensive alteration and structural preparation from the underlying Pig Well Graben and the district-scale Keith-Kilkenny Shear zone. Wide spaced aircore with some localised RC and core drilling have been completed up to 2011. Four diamond drill holes to the west of the area targeted base metal anomalies around 2013.
More work has been completed at Linger and Die Goldfield that is a collection of 15 defined historical prospects covering an area extending over 1km east-west and 2km north-south and has a similar prospective geological setting to the nearby 4.1Moz King of the Hills deposit. Historical production records indicate that average grades of between 1-2 ounces per tonne were extracted from the late 1800’s. Two small open cuts (<30m deep) were developed in the 1980’s/90’s and toll-treated. One pit returned processed grades in excess of 10g/t and the other approximately 4g/t. One un-explained high-grade RC drilling intercept of 9m @ 17g/t is located under one pit.
Exploration coverage around Linger and Die has been generally focused on potential near-surface high-grade zones. Only in the past decade has a greater understanding of the likely mineralisation controls been developed and many targets and potential extensions remain either untested or poorly tested.
Elsewhere on the greater tenement package, more recent work has involved the compilation of existing data and field mapping and sampling, resulting in the identification of various alteration styles with associated mineralisation potential. Significant areas of hydrothermal alteration were identified, interpreted being associated with the structural preparation associate with the granitoid intrusion, the Keith-Kilkenny Fault and Pig Well Graben.
An extensive network of veins was identified proximal to the Bundarra batholith that appears associated with intense hydrothermal alteration. Rock chip sampling in the exposed quartz veining has returned assays of up to 12g/t gold with elevated silver and bismuth. Two main mineralisation orientations are indicated, an east-west trend (sub-parallel to the granite contact – the Linger and Die trend) and the other trending NNW. The strike length of a number of separate quartz veining structures extends to several kilometres. A series of low-level gold anomalies were identified coinciding with the Emu Shear structural trend adjacent to an interpreted basalt-felsic-volcaniclastic contact.
Geophysical surveys (on E37/1287 and E37/1355) in the past decade provide encouragement on an interpreted extension of the Jaguar trend. Four core holes tested this zone with encouraging disseminated sulphide mineralisation intercepted and further drilling was recommended.
With approximately 85% of the tenement shrouded by recent alluvial cover, the majority of the interpreted mineralisation trends have had either no follow-up or very limited follow-up exploration. The previous targeting work will allow OZZ to undertake an immediate and more focused exploration effort leading to early drill campaigns.
Gold mineralisation will be the priority target, but a review of the base metal and molybdenum potential is expected to provide further targets. Soil sampling and geophysical surveys will be planned to better localise targets with drilling intended in the second half of 2022. Given the size and prospectivity of the lease area, Pinnacle Well will remain a key focus for OZZ.
The Pinnacle Well prospect is surrounded by extensive pyrophyllite alteration. Pyrophyllite (Al2Si4O10(OH)2) is a hydrated aluminum silicate, a talc group mineral. Following previous explorer’s recommendations, further work will be undertaken to assess the commercial potential of the pyrophyllite mineralisation.