Mantle Minerals Expands Bonaparte Basin Presence with Carlton Hill Licence and Far West Metals Acquisition

Carlton Hill Licence Grant Enables Systematic Exploration of Lead-Zinc-Silver Targets

The awarding of Exploration Licence E80/6170 marks a significant operational milestone for Mantle Minerals, transitioning the company from preliminary desktop and reconnaissance work to active on-ground exploration at Carlton Hill. Granted by the Western Australian Department of Mines, Petroleum and Exploration in the quarter ending 30 June 2026, the licence authorises Mantle to undertake geological mapping, surface sampling, and target investigation across the tenement. Initial efforts will focus on evaluating the potential for carbonate-hosted copper-lead-zinc-silver mineralisation and refining priority zones for future geophysical surveys or drilling.

Strategically situated about 50 kilometres north of Kununurra within the northern Bonaparte Basin, the Carlton Hill Project lies along the Carlton Shelf structural trend, recognised for its prospectivity in carbonate-hosted lead-zinc-silver deposits. Previous work by Mantle included desktop data collation, remote sensing, and reconnaissance geological mapping to enhance understanding of the area's stratigraphy and structural geology. Earlier exploration by base metals explorer Mincor identified 44 structural anomalies within the region, several of which fall inside Mantle’s tenure. Mincor’s partnership with Japanese state-backed JOGMEC involved a detailed heliborne VTEM survey to detect mineralisation beneath alluvial cover before Mincor shifted focus away from base metals, leaving multiple targets untested that Mantle now intends to evaluate in detail.

Acquisition of Far West Metals Enhances Carlton Hill Tenure and Reduces Liabilities

Mantle Minerals secured a binding agreement to acquire Far West Metals Ltd (ACN 626 676 104) and its 100% owned tenement application E80/6134, adjacent to Mantle’s Carlton Hill licence. This acquisition significantly expands Carlton Hill’s footprint within a highly prospective sediment-hosted base metal system near Boab Metals’ Sorby Hills deposit. The deal involved acquiring 100% of Far West’s shares for a nominal $300 and settling approximately $250,000 of Far West’s third-party debt by paying $100,000, effectively reducing liabilities at a substantial discount.

Combining the licence grant with the Far West acquisition strengthens Mantle’s exploration position by consolidating adjacent tenements under unified ownership, facilitating a coordinated exploration strategy across an expanded area. Proximity to Boab Metals’ Sorby Hills deposit, which boasts a Mineral Resource Estimate of 47.3 million tonnes grading 3.1% lead, 0.4% zinc, and 35 grams per tonne silver, underpins the geological rationale for Mantle’s exploration focus.

Strategic Location Near Boab Metals’ Sorby Hills Deposit

The Carlton Hill Project is strategically positioned within Western Australia’s Bonaparte Basin mineral district, approximately 35 kilometres east of Boab Metals Limited’s Sorby Hills Pb-Zn-Ag deposit—one of the region’s most significant discoveries. The Sorby Hills deposit’s Mineral Resource Estimate of 47.3 million tonnes at 3.1% lead, 0.4% zinc, and 35 grams per tonne silver highlights the district’s capacity for economically significant carbonate-hosted base metal mineralisation. This proximity offers a strong geological analogue for the mineralisation Mantle targets within its licence areas.

Despite this, Carlton Hill remains relatively underexplored with limited modern exploration. This combination of proven regional potential and limited systematic exploration presents an attractive opportunity for junior explorers. The Carlton Shelf’s structural setting, coupled with access to historical datasets from Mincor and JOGMEC, provides a solid foundation for prioritising and testing targets. The 44 structural anomalies identified by Mincor, several within Mantle’s tenure, offer a pre-screened portfolio of drill targets for systematic evaluation.

Yule River Project Progress Hinges on Native Title Access Agreements

Located about 35 kilometres west of Port Hedland, the Yule River Project is Mantle’s gold and specialty metals exploration asset within the structurally complex Mallina Basin. Situated at the intersection of the Sholl and Yule River Shear Zones, the area is prospective for intrusive-style gold, VHMS, orogenic gold, and magmatic nickel-copper-palladium-platinum mineralisation. The geological setting is analogous to De Grey Mining’s Hemi gold deposit, underscoring significant regional gold potential.

Mantle has conducted high-resolution gravity, passive seismic, and historical aeromagnetic surveys at Yule River, identifying priority targets including discrete non-magnetic gravity highs and coincident gravity-magnetic anomalies prospective for VHMS, orogenic gold, and magmatic nickel-copper mineralisation. However, drilling remains contingent on finalising native title access arrangements. The company continues to work on formalising these agreements, noting that heritage surveys or heritage monitors will likely be required before drilling. This native title consultation is a critical regulatory and stakeholder milestone necessary before advancing exploration.

Pardoo Project and Highway Nickel Deposit Resource Overview

Mantle Minerals’ Pardoo Project, approximately 120 kilometres east of Port Hedland, lies within the Pardoo Shear Zone of the eastern Pilbara Craton, known for iron-oxide and shear-related base metal mineralisation. During the quarter ended 30 June 2026, Mantle continued desktop reviews and compilation of historical data to better understand the district’s mineralisation framework and identify targets.

The Pardoo Project hosts the Highway Nickel Deposit, with a JORC 2012-compliant Mineral Resource Estimate (Indicated and Inferred) of 16.463 million tonnes at 0.407% nickel, equating to roughly 67,005 tonnes of contained nickel. This includes 11.064 million tonnes at 0.407% nickel in the Indicated category (about 45,028 tonnes nickel) and 5.400 million tonnes at 0.408% nickel in the Inferred category (approximately 22,031 tonnes nickel). The deposit also contains copper (0.117%) and cobalt (0.032%) credits, contributing 19,208 tonnes of copper and an unspecified cobalt tonnage. The resource estimate applies a 0.300% nickel cutoff above minus 200 metres relative level and incorporates a 12,500 ppm topcut for nickel to ensure statistical validity.

Board Strengthened by Appointment of Industry Veteran Martin Helean

During the quarter, Mantle Minerals appointed Mr. Martin Helean as a Non-Executive Director effective 29 May 2026. Bringing over 30 years of senior management experience across mining, exploration, manufacturing, and construction sectors, Mr. Helean’s expertise aligns with Mantle’s operational focus. Specific details of his prior roles were not disclosed.

This appointment followed the resignation of Mr. Johnathon Busing as Non-Executive Director and Joint Company Secretary. Mr. Kieran Witt remains as Company Secretary, ensuring continuity. These governance changes reflect Mantle’s strategic evolution as it advances from early-stage exploration toward more intensive field programs at Carlton Hill and potential drilling at Yule River.

Capital Return to Shareholders Progressing

Mantle Minerals continued processing a capital return to shareholders during the quarter, following approval at the 2025 Annual General Meeting. Most shareholders have received distributions, with remaining payments underway. The company did not disclose the total capital returned, per-share distribution, or expected completion date. This capital return represents a shareholder value distribution and aligns with Mantle’s capital management strategy amid funding needs for exploration at Carlton Hill and other projects.

Exploration Strategy Focused on High-Potential Western Australian Districts

Mantle Minerals’ project portfolio demonstrates a strategic emphasis on Western Australian regions with proven mineral potential and exploration upside. The Carlton Hill Project targets carbonate-hosted base metals near a significant Boab Metals deposit, indicating district-scale mineralisation. The Yule River Project’s structural setting parallels De Grey Mining’s Hemi gold deposit, while the Pardoo Project’s Highway Nickel Deposit provides a quantified resource asset.

This commodity and geographic diversification supports exposure across multiple mineralisation styles and commodity cycles. Concentrating efforts within the Bonaparte Basin and Pilbara Craton leverages established mining infrastructure, historical data, native title frameworks, and proven mineral endowment. Mantle’s staged progression from desktop studies to licence grants and drilling preparation reflects disciplined risk management before capital-intensive exploration. Investors will monitor how effectively Mantle converts its expanded Carlton Hill tenure into drilling success and advances native title agreements at Yule River.

Regulatory and Stakeholder Engagement in Western Australian Exploration

Exploration in Western Australia requires adherence to multiple regulatory and stakeholder engagement protocols, evident across Mantle’s projects. The grant of Exploration Licence E80/6170 at Carlton Hill demonstrates Mantle’s compliance with Department of Mines, Petroleum and Exploration requirements. However, native title obligations remain a timing constraint at Yule River, where access negotiations and heritage monitor engagement are prerequisites for drilling.

These regulatory frameworks, including the Native Title Act 1993 and related state legislation, mandate consultation with Indigenous groups holding native title or claims. While standard, these processes require time and resources. Mantle’s active native title negotiations and ongoing engagement indicate professional management of these obligations. Specific timelines for native title completion or drilling commencement at Yule River were not provided, leaving investors to await updates in future reports.