Rimfire Pacific Mining Limited – Fifield District Scandium Resource Builder Investigating Lower-Cost Leaching Pathway at Murga
- Noel Ong
- 21 hours ago
- 9 min read
Murga's Low Iron Scandium Enters Metallurgical Testing as Simpler Leaching Route Could Reshape the Deposit's Economics
Samso News | ASX: RIM | Critical Minerals | Scandium — Fifield District, NSW
Rimfire Pacific Mining Ltd (ASX: RIM) occupies a specific and differentiated position within Australia's scandium landscape. Samso has taken a liking to Rimfire because of the potential possibilities of the Murga Scandium Deposits with its low iron content. Over the years, I have learnt that to look out for these small things that make a lot of difference in terms of understanding the potential of a mineral resource story.
Currently, the narrative is that it is approximately 16% Fe compared to 34% Fe at neighbouring deposits, which, according to the company, opens the possibility of Atmospheric Tank Leaching or Vat Leaching rather than the more capital-intensive and technically complex High Pressure Acid Leaching (HPAL) route that other Fifield District operators are contemplating. If that simpler leaching pathway proves economically viable, it materially changes the capital intensity equation for Murga relative to its peers.
The metallurgical study now underway at Simulus Laboratories is the test that will determine whether that advantage is real. With a total global scandium resource inventory of 10.6Kt Sc across Melrose, Currajong, and Murga and the Malamute Prospect offering additional regional upside.
From a Samso perspective, Rimfire has assembled a resource base that positions it among the most significant scandium players in Australia's most prospective scandium district. The metallurgical question at Murga is the next pivotal variable the market should track.
Bottle Roll Testing Commences at Murga as Rimfire Investigates Whether Low Iron Scandium Can Be Extracted Without High-Pressure Acid Leaching
Samso News | ASX: RIM | Source: Rimfire Pacific Mining Limited ASX Release, 12 May 2026
Introduction
Rimfire Pacific Mining Limited has announced the commencement of a metallurgical study on low iron scandium mineralised material from its Murga Scandium Deposit in the Fifield District of central New South Wales. The study, being conducted by Simulus Laboratories in Perth under the guidance of the company's Metallurgical Process Consultant, Boyd Willis, is designed to determine whether Murga scandium can be economically recovered at atmospheric pressures — a question with significant implications for the deposit's capital intensity relative to other scandium projects in the district.
The central distinction at Murga is its iron content. The deposit carries an average iron grade of approximately 16% Fe, materially lower than comparable scandium deposits in the Fifield District.
Rio Tinto's Burra Scandium Deposit, for example, holds a combined Mineral Resource iron grade of 34% Fe. That difference in iron content is commercially significant because high-iron scandium deposits typically require High Pressure Acid Leaching (HPAL) which is a metallurgical process that is both capital-intensive and technically complex.
If Murga's lower iron content allows the use of Atmospheric Tank Leaching or Vat Leaching, the capital requirements for bringing the deposit into production would be substantially lower. The metallurgical study now underway is the first systematic test of that hypothesis using Murga material.
Figure 1: Aircore drilling operations at Rimfire's Fifield project in central NSW — the same drilling technique used across the Murga Scandium Deposit to generate the resource inventory now underpinning the metallurgical study. Source: (Rimfire Pacific Mining Limited).
Stage 1 of the study involves bottle roll leach testing at atmospheric pressures on two representative samples of laterite/clay and saprolite-hosted low iron scandium mineralised material.
Initial findings from Stage 1 are expected by late June 2026. The outcome of that stage will determine the pathway for Stage 2, which may involve agitated leach or vat leach testing depending on particle size results. Stage 2 completion is anticipated potentially as early as the September 2026 quarter.
In parallel with the metallurgical study, the company's Inferred Mineral Resource at Murga now stands at 56.1Mt at 138ppm Sc for 7,760t Sc, contributing to a total Fifield scandium resource inventory of 10.6Kt Sc across the company's three deposits.
Management Commentary
David Hutton, Managing Director and CEO of Rimfire Pacific Mining, framed the commencement of bottle roll testing as a step toward realising what the company regards as Murga's key point of difference within the Fifield District. Hutton pointed to the low iron character of the mineralisation as a potential technical breakthrough relative to competing scandium projects in the district, which are contemplating HPAL — a significantly more capital-intensive process. He confirmed the company's primary corporate objective remains building a globally significant scandium resource inventory at Fifield, and expressed confidence that further drilling success at both Murga and the Malamute Prospect could substantially grow the inventory beyond its current level.
" Murga's low iron scandium represents a potential technical breakthrough and is a key point of difference to the other scandium deposits in the area."
— David Hutton, Cheif Executive Officer, Rimfire Pacific Mining Limited
Hutton also contextualised the study within the company's broader resource-building trajectory, noting that the total Sc Oxide resource base of more than 16Kt across the Fifield portfolio places Rimfire in a strong position within the district. The metallurgical study is presented as complementary to, rather than separate from, the resource growth strategy — the logic being that a confirmed lower-cost processing pathway at Murga would materially enhance the commercial case for the deposit's development alongside the inventory-building work that continues at Malamute.
Near-Term Milestones to Watch
What Investors Should Monitor Following This Metallurgical Study Announcement
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Figure 2A: Fifield aircore drilling. (Source: Rimfire Pacific Mining Limited) | Figure 2B: Rimfire geologists on the ground at Fifield. (Source: Rimfire Pacific Mining Limited) |
Samso Concluding Comments
The Rimfire story is probably at a stage where interested investors may want to take some notice. This may not be the timing to jump in but the 12 May 2026 announcement from Rimfire Pacific Mining is pretty much the commencement of a study that will answer a binary question: can Murga's scandium be economically extracted without High Pressure Acid Leaching?
This is effectively the key quesiton for the Rimfire Story.
The keya spect of this discussion is that currently HPAL is the dominant proposed processing route for comparable scandium deposits in the Fifield District. The take away for those that are new to this story is that the HPAL process carries a substantially higher capital cost and technical complexity than atmospheric leaching alternatives.
IF bottle roll testing and subsequent stages confirm that Murga's low iron mineralisation responds adequately to atmospheric conditions, the deposit's development economics would be fundamentally different from those of its neighbours.
IF the results are inconclusive or negative, the company would need to reassess its processing approach.
Figure 3: Core cutting at one of Rimfire's Fifield project drill programs. The HQ quarter core samples now being tested at Simulus Laboratories in Perth were collected from diamond drillhole FI2679 at the Murga Scandium Deposit. Source: Rimfire Pacific Mining.Schematic diagram of the multi-stage metallurgical study process — Stage 1 bottle roll testing through to Stage 2 agitated or vat leach testing — illustrating the study pathway from commencement to economic viability assessment
Murga's average iron grade of approximately 16% Fe compares with 34% Fe at Rio Tinto's Burra deposit. According to the managmeent ethos, that gap is the difference between a deposit that may be amenable to surface-condition leaching and one that requires an autoclave-based high-pressure process.
The capital cost of an HPAL facility, inclusive of the autoclave circuit, materials-handling infrastructure, and the operational complexity of managing high-temperature, high-pressure acid conditions, is one of the primary reasons that high-grade scandium deposits globally have been slow to reach commercial production despite strong pricing fundamentals for the metal.
A viable atmospheric leaching route at Murga would remove that barrier, at least in principle. This study now underway is designed to test whether the mineralogy supports that outcome.
Figure 4: A diamond drill rig at one of Rimfire's NSW project sites. Diamond drilling at Murga — including drillhole FI2679, the source of the metallurgical test samples — has provided the HQ core now being assessed for atmospheric leaching potential at Simulus Laboratories. (Source: Rimfire Pacific Mining Limited)
The resource inventory context is also worth holding in mind. Rimfire's 10.6Kt Sc total inventory at Fifield, which is spread across three deposits is a material holding in a district that has attracted significant attention from major operators. The Murga deposit alone contributes 7,760t Sc, which accounts for the majority of that inventory.
If the study results indicate that there is a win for Rimfire, then one can start factoring some potential upside with the Malamute Prospect, which located 40km to the north and not yet included in any resource estimate.
While the company aim to participate in the Scandium story with a globally significant scandium resource base at Fifield is defintely more than intertesting. For the moment, the metallurgical work now underway at Murga will be what the industry is awaiting.
Previous Samso News Coverage
Samso has followed Rimfire Minerals across multiple ASX releases. The following represents our prior published coverage of the company:
April 14, 2026 -
April 6, 2026 -
About Rimfire Pacific Mining Limited
Rimfire Pacific Mining is an ASX-listed critical minerals explorer focused on building a globally significant scandium resource inventory in Australia's Fifield Scandium District, located approximately 70km northwest of Parkes in central New South Wales.
The company's scandium portfolio comprises three deposits — Melrose, Currajong, and Murga — together delivering a combined global resource inventory of 10.6Kt Sc (16.2Kt Sc Oxide). The Murga Scandium Deposit, the most recently updated, holds an Inferred Mineral Resource of 56.1Mt at 138ppm Sc for 7,760t Sc.
Murga is notable within the Fifield District for its relatively low average iron content of approximately 16% Fe, which creates the possibility that its scandium could be extracted using Atmospheric Tank Leaching or Vat Leaching — simpler and less capital-intensive techniques than the High Pressure Acid Leaching (HPAL) methods being considered by operators of higher-iron deposits in the same district. A metallurgical study to investigate this pathway is now underway.
The company also holds the Malamute Scandium Prospect approximately 40km north of Murga on its 100%-owned Rabbit Trap Project, offering regional resource growth optionality.
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