The Webb Project is located in northern Western Australia in the Aileron province of the West Arunta Orogen (WAO) and has been recognised by CGN, our neighbours and Geoscience Australia as being highly prospective for iron oxide copper gold (IOCG)-style mineralisation and nickel sulphide mineralisation. In addition, CGN has already demonstrated the potential for diamondiferous kimberlites discovering the largest kimberlite field in Australia. The exciting part of the story is that other than recent work completed by CGN our section of the WAO, although highly prospective, is essentially unexplored for copper or nickel.
During the exploration for diamonds CGN has assembled high-quality regional data sets. Comprising multielement geochemistry from drill holes, tenement-wide detailed aeromagnetic survey, a detailed Falcon gravity survey as well as publicly available date from the GSWA and Geoscience Australia. During previous exploration the CGN team intersected anomalous copper (up to 0.23% Cu) and nickel (up to 1.15% Ni) as well as highly anomalous cobalt and rare earth elements (REE) in multiple drill holes. Many of the copper results are also anomalous with respect to elevated elemental results for chromium, cobalt, nickel and uranium indicative of IOCG mineralisation. This has encouraged CGN to focus more resources into the exploration for IOCG’s.
A reinterpretation of the geophysics results and review of the company geochemistry and geology databases has highlighted there there are multiple IOCG targets, as well potential for magmatic nickel and rare earth elements related to potential carbonatite intrusives.
Identified six key targets as the focus of our near term exploration activities:
A strong IOCG target featuring a coincident gravity and magnetic anomaly in a favorable structural setting. This target is partially funded by the WA Government Exploration Incentives Scheme (EIS).
An IOCG target comprising a major gravity feature adjacent to crustal scale structures. This target is also partially funded by the EIS.
A potential magmatic nickel target comprising a major magnetic feature adjacent to crustal scale structures with highly anomalous nickel values intersected in drilling.
A target where a 37m interval of highly anomalous REE was intersected in drilling, showing carbonatite affinities adjacent to a large intrusive feature in teh magnetic data.
Snorky & Horton
These targets feature strong gravity features on major structures adjacent to copper hits in previous drilling.
CGN considers four potential deposits
IOCG-style supported by pathfinder minerals present in supergene zone and geophysical signatures aligned with IOCG in favourable structural settings (Targets – Tantor, Surus, Snorky and Horton).
Orthomagmatic nickel supported by very high nickel results in some cases, over 1% elemental nickel grades adjacent to sill-like magnetic features (Target Shep)
REE mineralisation in alkaline magmatic intrusive rocks – kimberlites and/or carbonatites with highly anomalous REE values over 37m in RC drilling (Target Hathi)
Diamondiferous kimberlites supported by recovered microdiamonds from loam samples in vicinity of kimberlite pipes (230 kimberlites remain to be tested)
Strong geological understanding
The IOCG model is well supported by geological understanding as well as important occurrences in the local region and anomalism within the project tenements. CGN has stated that this model will be the primary focus of ongoing exploration.
IOCG prospectivity is supported by:
- Favourable geological and geodynamic setting as described by Geoscience Australia, when comparing other metallogenic models supporting the prospectivity of the West Arunta Orogen for IOCG mineralisation
- Projects in the local region including Pokali (Rincon) and Grapple and Bumblebee (IGO), which are described as having important characteristics of IOCG mineralisation
- Neighbouring explorers who are actively exploring IOCG-style mineralisation and whose work supports a similar model for the mineral anomalism recovered from the Webb Project
- CGN has detected significant anomalism in copper and other elements associated with IOCG through the course of drilling testing of kimberlite targets
- The interpretation of geophysical data by CGN which has revealed gravity and magnetic targets with potential for IOCG mineralisation.
Nickel prospectivity is supported by:
- Presence of high-grade nickel in drillhole W14RC009
- Mineralised Intercept of 2 m at 1.15% Ni from 66–68 m in a partially sampled 25 m zone averaging 0.52% Ni
- Intercept also highly anomalous in chromium, copper, magnesium, iron, vanadium and sulphur, with low silica
- The drillhole directly overlies a distinct sill-like feature in the magnetic data.
REE prospectivity is supported by:
- A significant intercept of REE in drillhole W14RC045.
- Mineralised intercept of 37 m (63–100 m) zone at 0.38% total rare earth oxide (“TREO”) with the highest value of 0.71% TREO near bottom-of-hole.
- The Intercept occurs adjacent to a coincident magnetic and gravity high interpreted as a possible carbonatite intrusive
- The drillhole aligns with a strong dyke feature in the magnetics that could have carbonatite affinities with the large intrusive features.