Highlights

  • Rimfire Pacific Mining shares rose 10.00% on 12 May 2026 following the release of a Murga Scandium metallurgical update.
  • Bottle roll leach testing has commenced to assess the economic recovery potential of Murga’s low-iron scandium mineralisation at atmospheric pressure.
  • Initial findings from Stage 1 testing are expected by late June 2026.
  • Murga’s inferred mineral resource estimate stands at 56.1Mt at 138ppm scandium for 7,760 tonnes of scandium.
  • Rimfire’s broader scandium inventory across the Fifield region now totals 10.6Kt scandium or 16.2Kt scandium oxide.
  • The company believes Murga’s lower iron content may support less Capital-intensive extraction pathways compared with other regional deposits.

Rimfire Pacific Mining (ASX:RIM) shares climbed 10.00% to AUD 0.011 during the afternoon session on 12 May 2026 after the company announced the commencement of metallurgical studies at its Murga Scandium Deposit in New South Wales. Despite the intraday rise, the stock remains down 63.33% over the past year.

Investor attention appeared to focus on the company’s efforts to evaluate whether Murga’s low-iron scandium mineralisation can be economically processed using atmospheric leaching techniques, which management believes may offer a less complex and potentially lower-cost extraction pathway compared with some neighbouring scandium projects in the Fifield district.

The latest update marks another step in Rimfire’s strategy to expand and develop its scandium presence in the region, where the company has been building what it describes as a globally significant scandium resource inventory.

Rimfire Pacific Mining is an Australian exploration company focused on critical minerals and base metals projects, with a growing emphasis on scandium opportunities in the Fifield district of central New South Wales. The company’s exploration portfolio includes the Murga, Melrose and Currajong scandium deposits, alongside the Malamute prospect located within its wholly owned Rabbit Trap Project.

Metallurgical Study Commences at Murga

The company confirmed that bottle roll leach testing is now underway on low-iron scandium mineralised material sourced from the Murga deposit.

The study is designed to determine whether scandium can be economically recovered under atmospheric pressure conditions rather than through more capital-intensive processing methods such as High Pressure Acid Leaching (HPAL), which is commonly considered for higher-iron scandium deposits.

Testing is being conducted by Simulus Laboratories in Perth under the guidance of Rimfire’s metallurgical process consultant, Mr Boyd Willis.

According to the company, the initial stage of the study involves bottle roll leaching tests on two representative composite samples taken from drillhole FI2679. The samples comprise laterite, clay and saprolite-hosted scandium mineralisation.

Bottle roll testing is typically used as a laboratory-scale process to simulate leaching behaviour, evaluate metal solubility kinetics and determine reagent consumption. The work is also intended to help estimate potential recovery rates and assess operational variables such as leaching duration and particle size.

Rimfire expects Stage 1 testing and review work to be completed by late June 2026.

The company indicated that the Stage 1 findings will determine the pathway for additional optimisation studies, which could involve agitated atmospheric leaching or static vat leach techniques during Stage 2 testing.

Stage 2 work may potentially conclude as early as the September 2026 quarter.

Low-Iron Characteristics Differentiate Murga

A major focus of the company’s announcement was Murga’s comparatively low iron content relative to other scandium deposits within the Fifield region.

Rimfire stated that Murga mineralisation carries an average iron grade of approximately 16% Fe, equivalent to 22.8% Fe₂O₃.

The company contrasted this with several nearby scandium projects, including Rio Tinto’s Burra deposit, which reportedly contains iron grades around 34% Fe or 48.7% Fe₂O₃.

Management suggested this lower iron composition could provide an important point of differentiation for Murga.

According to the company, lower iron levels may increase the possibility of recovering scandium using atmospheric tank leaching or vat leaching techniques, which are generally considered less capital intensive and operationally simpler than HPAL processing routes.

This potential processing advantage appears to be one of the key reasons investors reacted positively to the latest update.

The Fifield region in central New South Wales has become one of Australia’s better-known scandium districts and hosts several advanced scandium projects, including Sunrise Energy Metals’ Syerston deposit and Australian Mines’ Flemington project.

Murga is positioned adjacent to these deposits approximately 70 kilometres northwest of Parkes.

Murga Resource Continues to Support Regional Scale

Rimfire also reiterated the current size of the Murga inferred mineral resource estimate.

The deposit currently hosts an inferred resource of 56.1 million tonnes grading 138 parts per million scandium, equivalent to approximately 212 parts per million scandium oxide.

This equates to an estimated contained resource of 7,760 tonnes of scandium or around 11,900 tonnes of scandium oxide.

The company stated that its broader scandium inventory across the Fifield district now totals 10.6 kilotonnes of scandium or 16.2 kilotonnes of scandium oxide, placing Rimfire among the larger scandium resource holders in the region.

Management also highlighted additional exploration upside through the Malamute Scandium Prospect, located roughly 40 kilometres north of Murga within the company’s 100%-owned Rabbit Trap Project.

Rimfire’s managing director David Hutton said the company remains focused on building a globally significant scandium inventory at Fifield and believes further drilling success could materially expand the existing resource base.

Why Atmospheric Leaching Matters

A key theme underpinning the update is the economic importance of processing methods in scandium development projects.

Scandium is commonly used in aluminium alloys, solid oxide fuel cells and various advanced technology applications. However, commercial scandium production remains relatively limited globally, meaning project Economics and extraction efficiency are often critical considerations for emerging developers.

High Pressure Acid Leaching methods, while capable of processing complex ores, generally require more sophisticated infrastructure, higher Capital Expenditure and increased operational complexity.

Rimfire’s latest testing program is therefore aimed at evaluating whether Murga’s mineralisation characteristics could support a comparatively simpler atmospheric leaching process.

Should the testing deliver favourable recovery outcomes, the company may be able to demonstrate a potential processing advantage relative to some higher-iron scandium deposits in the district.

The company stressed that further metallurgical data will still be required before any economic viability conclusions can be reached.

Study Timeline and Next Steps

Rimfire outlined a staged approach for the metallurgical program.

Stage 1 bottle roll testing is currently in progress and is expected to deliver initial findings by late June 2026.

The results from this phase will guide subsequent optimisation studies, potentially involving atmospheric agitated leach or vat leach test work depending on particle size characteristics and recovery outcomes.

Management indicated that Stage 2 testing may conclude as early as late September 2026.

Following completion of both stages, Rimfire hopes to determine whether atmospheric leaching could represent an economically viable recovery pathway for the Murga deposit.

The company also confirmed that the announcement did not contain any new exploration results beyond previously released resource estimates.

What This Means for Investors?

Rimfire Pacific Mining’s latest update places attention on the technical and processing characteristics of the Murga Scandium Deposit rather than new drilling outcomes.

The commencement of metallurgical testing appears to have been viewed positively by the market, particularly given the potential implications of Murga’s lower iron content and the possibility of utilising less capital-intensive extraction methods.

While the project remains at a relatively early evaluation stage, the study represents an important milestone in assessing the economic development potential of the deposit.

Investors are likely to monitor upcoming Stage 1 test results expected in late June 2026, as well as any future indications regarding scandium recovery rates, processing pathways and broader project economics.

The company’s expanding scandium inventory within the Fifield district may also remain an area of interest as Rimfire continues exploration and metallurgical work across its broader portfolio.