GreenTech Metals has uncovered material upside potential at its Munni Munni PGE-Cu-Ni project through a detailed review of historical drilling data, with maiden drilling assay results expected in mid-April 2026.
- Historic data review reveals high-grade PGE zones and under-recognised copper and nickel mineralisation
- Eastern shallow plunge zones identified, potentially suitable for open-cut mining
- Maiden drilling and resampling program completed in March 2026, results pending
- Plans underway for expanded resource re-estimation under JORC 2012 standards
- Extensive validation of historical data supports exploration strategy and future drilling
Historic Data Review Highlights Exploration Upside
GreenTech Metals Limited (ASX:GRE) has announced a comprehensive review of historical drilling data at its Munni Munni PGE-Cu-Ni project in Western Australia's Pilbara region. The review, which encompassed core and logs from 396 drill holes, has identified material upside potential beyond the historic Mineral Resource Estimate (MRE) of 24 million tonnes at 2.9 grams per tonne PGE4, equating to approximately 2.2 million ounces, originally reported by Helix Resources Limited in 2002.
Key findings from the review include the identification of multiple high-grade platinum group element (PGE) zones within the Ferguson Reef, under-recognised copper and nickel mineralisation outside the previously defined PGE domains, and shallow eastern plunge zones of mineralisation that extend from surface. These shallow zones are considered potentially amenable to open-cut mining methods, which could have implications for project development.
Maiden Drilling and Resampling Program Completed
GreenTech completed its maiden drilling and resampling program at Munni Munni in March 2026, targeting high-grade extensions of the Ferguson Reef and validating historic data. The program leveraged well-preserved historic drill core, which allowed for an expanded resampling effort. Assay results from this program are expected in mid-April 2026 and will be critical in supporting an expanded re-estimation of the historic MRE in accordance with the JORC Code (2012).
This recent drilling phase was part of a broader strategy to validate and build upon the historic resource, following GreenTech's acquisition of a 70% stake in the project earlier in February 2026. The acquisition consolidated GreenTech's district-scale footprint in the West Pilbara, adjacent to its Whundo deposit, and was accompanied by an accelerated drilling campaign to verify and potentially expand the resource base. The company’s approach to the maiden drilling program and historic core resampling has been detailed in a prior update, which highlighted the efficiency gains and cost savings achieved by utilising existing core samples rather than relying solely on new drilling GreenTech Metals Accelerates Munni Munni Resource Validation with Historic Core Resampling.
Geological Context and Historical Work
The Munni Munni project is situated within the Munni Munni Intrusive Complex (MMIC), a layered ultramafic-mafic intrusive body approximately 25 by 9 kilometres in size. Mineralisation is primarily hosted within two reef zones: the Ferguson Reef, a PGE and sulphide-bearing zone proximal to the gabbroic-ultramafic contact, and the Lower Reef, which straddles the pyroxenite-lower ultramafic contact. The PGE mineralisation is characteristically chromite-poor and shares geological similarities with the Great Dyke of Zimbabwe.
Exploration at Munni Munni dates back to the mid-1980s, with significant drilling and mapping undertaken by Hunter Resources, Helix Resources, Platina Resources, Artemis, and Alien Metals over subsequent decades. These efforts established the initial resource framework and identified key mineralised zones. However, the historic resource estimates were not reported under the JORC Code (2012) and require validation and re-estimation to meet current reporting standards.
Future Work and Resource Re-estimation
GreenTech plans to use the assay results from the maiden drilling and resampling program to validate and expand the historic resource estimate. The company intends to undertake a multi-element geochemical exploration program to better understand the controls on mineralisation and to identify further exploration targets within the 225 square kilometre project area.
The company has emphasised that the historic resource estimates are considered historical and have not been classified as mineral resources or ore reserves under JORC 2012. Further exploration and evaluation work will be necessary to confirm whether the historical estimates can be reported as compliant mineral resources. GreenTech is also conducting quality assurance and quality control (QA/QC) validation of the historic data to support the upcoming resource re-estimation.
Chief Executive Officer James Rattenbury commented that the ongoing interrogation of the historic database has reinforced the conviction of a compelling larger-scale opportunity at Munni Munni, with potential repeats of PGE reef horizons and higher tenor copper and nickel sulphide mineralisation, including shallow zones. The company looks forward to the assay results to support the resource upgrade and to guide future exploration and drilling programs.
Bottom Line?
GreenTech Metals’ detailed historic data review and maiden drilling program position the Munni Munni project for a potential resource upgrade, but confirmation depends on forthcoming assay results and further validation under JORC 2012 standards.
Questions in the middle?
- How will the upcoming assay results influence the scale and confidence of the Munni Munni resource estimate?
- What are the implications of the identified shallow eastern plunge zones for mining methods and project economics?
- How might GreenTech’s expanded multi-element exploration program refine the understanding of mineralisation controls at Munni Munni?