Highlights

  • Hillgrove Resources shares rose 4.76% on 21 May 2026 following a Partnership announcement with Havilah Resources.
  • The agreement gives Hillgrove the right to earn up to an 80% interest in the Mutooroo Copper Project.
  • Mutooroo hosts a sulphide mineral resource of 12.5Mt at 1.53% copper.
  • Hillgrove plans to complete a pre-feasibility study using its existing Kanmantoo processing Facility.
  • The staged transaction includes up to AUD 10 million in PFS expenditure and drilling commitments.
  • Hillgrove believes the project could support copper production beyond 20kt per annum, subject to further studies.

Hillgrove Resources Ltd (ASX:HGO) shares gained 4.76% to AUD 0.044 during the afternoon session on 21 May 2026, with investors responding to the company’s latest strategic update involving the Mutooroo Copper Project in South Australia. Despite today’s movement, the stock remains around 10% higher over the past year.

The market reaction followed the announcement that Hillgrove Resources and Havilah Resources Ltd had entered into a binding agreement that could allow Hillgrove to earn an 80% interest in the Mutooroo Copper Project through a staged farm-in structure. The agreement also includes plans for a pre-feasibility study (PFS) focused on processing Mutooroo ore through Hillgrove’s existing Kanmantoo processing facility.

The update appeared to attract investor attention due to the project’s existing resource base, the proposed use of established infrastructure, and the phased structure designed to manage development risk and Capital allocation.

Partnership Centres Around Existing Processing Infrastructure

A key aspect of the proposed partnership is Hillgrove’s plan to Leverage its operating Kanmantoo processing plant rather than pursue a standalone processing solution at Mutooroo. According to the companies, this approach could potentially reduce both development capital requirements and execution risk.

The Mutooroo Copper Project is located in South Australia’s Curnamona Province, approximately 60 kilometres southwest of Broken Hill. The project sits close to the Transcontinental railway line and Barrier Highway, providing potential access to established freight infrastructure.

Importantly, the rail line passes near Hillgrove’s Kanmantoo processing facility, creating the possibility of transporting ore from Mutooroo to Kanmantoo for processing. The companies stated that previous work indicates the sulphide ore may be suitable for processing at the Kanmantoo plant, although further metallurgical testing will form part of the proposed study work.

Management indicated that utilising existing infrastructure could help streamline development pathways while limiting the need for large-scale new processing infrastructure and tailings facilities.

Mutooroo Resource Base Draws Attention

The Mutooroo project already hosts a sizeable sulphide mineral resource estimate, which forms part of the rationale behind the agreement.

According to the released details, the sulphide JORC Mineral Resource Estimate stands at 12.5 million tonnes grading 1.53% copper, 0.16% cobalt and 0.20 grams per tonne gold. This equates to approximately 191,700 tonnes of contained copper, 20,000 tonnes of cobalt and 80,600 ounces of gold.

The companies noted that drilling over several decades has outlined broad sulphide zones with demonstrated geological continuity. Mineralisation also remains open along strike and at depth, suggesting potential opportunities for future resource growth.

From Hillgrove’s perspective, the existing resource base offers a platform to focus the proposed PFS on Mining, logistics and processing pathways rather than starting from an early-stage exploration concept.

The project also contains oxide material, bringing the total resource inventory to more than 13 million tonnes.

Hillgrove Targets Copper Production Growth

One of the more closely watched aspects of the announcement was Hillgrove’s view that, subject to successful study outcomes and additional technical work, Mutooroo could potentially help lift the company’s annual copper production beyond 20,000 tonnes.

The company stated that the transaction aligns with its broader strategy of using the Kanmantoo processing facility as a centralised processing hub for regional deposits.

At a time when global copper discoveries are becoming less frequent and project development costs remain elevated, the company described the transaction as a capital-efficient growth option that could support long-term production expansion.

Hillgrove Managing Director and CEO Bob Fulker noted that Mutooroo’s grade profile, logistics positioning and proximity to rail infrastructure complement the company’s operational model. He also highlighted the staged development structure as a disciplined approach to capital deployment.

The company indicated that initial work programs will focus on validating technical assumptions before larger expenditure commitments are made.

Farm-In Structure Includes Staged Investment

The transaction has been structured across multiple stages, allowing Hillgrove to progressively evaluate the project before making a final investment decision.

Under Stage 1, Hillgrove will issue AUD 5 million worth of fully paid ordinary shares and attaching unlisted Options to Havilah, subject to the renewal of Exploration Licence EL6592 on terms acceptable to Hillgrove.

The consideration includes approximately 116.3 million Hillgrove shares priced at 4.3 cents each, alongside an equal number of unlisted options exercisable at 5.2 cents.

As part of the earn-in arrangement, Hillgrove will fund and complete a pre-feasibility study estimated at approximately AUD 10 million over a period of up to 24 months.

The company has also committed to undertaking at least 5,000 metres of drilling aimed at improving resource confidence at Mutooroo.

The study process itself has been split into two phases.

Phase 1 is expected to involve approximately AUD 2 million in expenditure and will focus primarily on metallurgical testing and rail logistics analysis. Only if these early workstreams indicate an economic pathway forward will the project proceed into the second phase.

Phase 2 would involve the remaining study expenditure and broader project assessment activities.

Upon successful completion of the PFS, Hillgrove may elect to acquire an 80% interest in the project through a Stage 2 payment valued at AUD 35 million. This payment would consist of a mix of cash and Hillgrove shares, with the cash portion ranging between 30% and 70% at Hillgrove’s discretion.

Study Work to Examine Mining and Logistics Pathways

The proposed pre-feasibility study is expected to assess multiple operational and technical areas linked to the project’s development potential.

Mining studies are planned to evaluate both open-pit and underground mining options. The concept currently contemplates initial open-pit mining followed by underground extraction of higher-grade sulphide ore.

The logistics assessment will focus on rail transport pathways and haulage costs associated with moving ore to Kanmantoo.

Processing studies are also expected to analyse potential plant configurations, including whether ore should be processed separately or blended with existing feed sources.

Additional workstreams are set to include geology, infrastructure planning, environmental approvals, workforce assessments, community engagement and financial modelling.

Importantly, the companies stated that independent reviews and risk assessments will be incorporated throughout the PFS process in order to identify and address potential project risks early in the study timeline.

Capital Structure Designed to Limit Early Risk

Another Factor that may have supported investor sentiment was the staged structure of the transaction, which allows Hillgrove to sequence expenditure across multiple development gates.

The company noted that the initial work program will be funded from existing Cash Flow rather than requiring immediate large-scale project financing.

The concept plan also benefits from avoiding the need to build a completely new processing plant or tailings storage facility, which can often represent significant capital burdens for standalone mining developments.

Instead, expected pre-production capital would primarily relate to mine development, logistics infrastructure, utilities and potential modifications at the Kanmantoo facility if required.

The agreement additionally includes a resource expansion payment mechanism under which Hillgrove would pay Havilah AUD 1 million for every additional 10,000 tonnes of contained copper added above the currently declared sulphide resource, capped at AUD 5 million.

What This Means for Investors

Hillgrove’s latest announcement appears to position the company toward a potential longer-term copper growth pathway centred around existing infrastructure and staged project development.

The proposed Mutooroo partnership gives Hillgrove exposure to a high-grade sulphide resource while allowing the company to assess technical and commercial viability progressively through a phased pre-feasibility process.

Investors also appeared to respond favourably to the possibility of leveraging the Kanmantoo processing facility, which could potentially lower capital intensity compared with a conventional standalone development approach.

While the project remains subject to further studies, metallurgical testing, regulatory approvals and a final investment decision, the transaction adds another potential growth avenue to Hillgrove’s South Australian copper strategy.

Market Participants are likely to continue monitoring upcoming drilling, metallurgy and logistics workstreams as the pre-feasibility study advances over the coming months.