Mount Ridley Mines — Maiden Gallium MRE Anchors a Multi-Element Regolith System Near Esperance
- Noel Ong
- 4 hours ago
- 7 min read
Announcement
Mount Ridley Mines Limited (ASX: MRD) has declared a maiden Inferred Gallium Mineral Resource Estimate (JORC 2012) of 838.7Mt @ 29.3 ppm Ga (39.5 ppm Ga₂O₃) at a 25 ppm Ga cut-off across three blocks at the Mt Ridley Project, ~55 km NE of Esperance, WA (Figure 1). Mineralisation is shallow, flat-lying and clay/saprolite-hosted, with strong associations to HREE and scandium—particularly in the central and northern corridors. The resource is supported by 732 holes for 30,112 m, extends >25 km in strike with a ~70 km² mineralised footprint, and sits inside a 575 km² tenure where ~70% remains untested.
Figure 1 – Regional Location Map showing the major Infrastructure such as Esperance Port, Road, and Rail (source: MRD)
Highlights - Gallium
(Figure 2)
Global MRE: 838.7Mt @ 29.3 ppm Ga (39.5 ppm Ga₂O₃) for 24,584 t contained Ga (cut-off 25 ppm Ga).
Block 1 – Central Gallium Corridor (incl. Keith’s HREE): 164.1Mt @ 29.8 ppm Ga (40.0 ppm Ga₂O₃) for 4,888 t Ga; strong correlation with HREE and scandium; shallow, flat-lying saprolite.
Block 2 – Northern Extension (incl. Winston’s HREE): 372.2Mt @ 30.3 ppm Ga (40.7 ppm Ga₂O₃) for 11,288 t Ga; continuation of the same clay profiles hosting REE/HREE.
Block 3 – Mia + Eastern Zone: 302.5Mt @ 27.8 ppm Ga (37.4 ppm Ga₂O₃) for 8,408 t Ga; overlays the Mia REE MRE of 168Mt @ 1,201 ppm TREO.
Geometry & Depth: Mineralisation from ~4 m to ~60 m depth; shallow, broad lenses in saprolite/laterite; >25 km strike and up to ~6 km width.
Work to Date: 732 drillholes / 30,112 m; domain modelling and ID² / kriging grade checks; densities applied by regolith unit; top cut 45 ppm Ga; parent blocks 50×50×1 m.
Scale & Positioning: Among the largest known gallium resources globally; logistics advantaged by proximity to Esperance Port, road, and power.
Figure 2: Mount Ridley Gallium Topographic Location Map highlighting the MRE Zones (source: MRD)
Mount Ridley Mines Non-Executive Director Mr Pedro Kastellorizos commented:
“The timing of our maiden gallium resource could not be more significant,” said Mount Ridley Mines Director, Pedro Kastellorizos. “With Australia and the United States now formally aligning on criticalminerals supply chains, the Mt Ridley Project represents one of the few new gallium discoveries outside of China, and it sits within an established rare-earth system. This resource establishes Mount Ridley as a serious participant in Australia’s emerging critical-minerals sector. Immediate focus will be on highvalue zones rich in gallium and heavy rare earths as we advance metallurgical testwork and partnership discussions to define a viable development pathway”
Geology & Mineral System (Why It’s There)
Host & Setting: Clay/saprolite-hosted Ga within the weathered profile across parts of the Grass Patch Complex (Blocks 1–2) and Biranup Complex granitoid gneiss (Block 3).
Controls: Spatial association with alkali-enriched gabbroic/plutonic dykes visible in aeromagnetics; highest grades near redox fronts in lower saprolite and at saprolite–fresh transition.
REE/HREE Link: Re-assay of legacy pulps confirms coincident Ga–REE enrichment; Keith’s (Block 1) and Winston’s (Block 2) show scale/continuity of HREE-rich clays.
The Mineral Resource areas known as Blocks 1, 2 & 3 are situated in the vicinity of Mt Ridley and Lake Halbert region of Western Australia (Figure 3,4 & 5).
Figure 3: Block 1 (source: MRD)
Figure 4: Block 2 (source: MRD)
Figure 5: Block 3 (source: MRD)
Table 1 presents the new JORC 2012 Resource Estimate (JORC 2012) for the Inferred category, applying at a >25 ppm Ga cut-off, the JORC 2012 Inferred MRE totals 838.7 Mt @ 29.3 ppm Ga (39.5 ppm Ga₂O₃)—placing Mt Ridley among the world’s largest known gallium resources. The 575 km² tenure hosts a ~69.9 km² mineralised footprint across three MRE zones, with >70% of the project still untested and slated for systematic drilling.
Table 1 - Mount Ridley Global Gallium Deposits Inferred Mineral Resource Estimate by Blocks (using a >25 ppm Ga cut-off)
Development Path (How It Could Advance)
Metallurgy: Concept is a mixed rare-earth carbonate as the primary product with gallium (and other critical elements) as secondary recoveries; testwork to include acid leach and hydrometallurgy (solvent extraction/ion exchange).
Program Design: Targeting zones most amenable to acid-leach processing; flow-sheet design underway; legacy pulp re-assays and re-logging to refine HREE/Sc targets.
Advisory Build-Out: Engagement with Australian & international processing/supply-chain experts (including U.S.–Australia critical minerals context).
Forward Plan & Near-Term Priorities
(Figure 6)
Extensional drilling SW of Block 1 along ~11 km × ~6 km corridor.
Infill drilling across the 3 km corridor between Blocks 1 & 2.
Step-outs east (~4.35 km) and west (~4.3 km) of Block 2 resource.
Block 3 extensions NE (~5.3 km) plus ~3 km E and ~4 km SW untested zones.
Drill extensions along alkali-rock corridors associated with better Ga intersections.
Metallurgical studies to confirm optimal acid-leach domains and refine the flow sheet.
Define requirements to deliver an Indicated Resource sufficient to support capex studies.
Figure 6: Location map showing the 3 MRE Zones, showing multiple untested zones over Interpreted Total Magnetic Intensity Images (source: MRD)
Market & Strategic Context (Why It’s Timely)
Supply Concentration: China has produced >98% of global Ga, historically as a by-product of bauxite/zinc refining; export controls and geopolitics have tightened supply.
Allied Policy Tailwinds: On 20 Oct 2025, the U.S.–Australia framework to secure critical minerals and rare earth supply chains highlighted WA projects as priorities, aligning with MRD’s path.
Samso Concluding Comments
Mount Ridley’s maiden inferred gallium resource gives the project tangible scale and, importantly, demonstrates a multi-element regolith system where Ga, HREE, and Sc appear to co-locate within shallow, lateritic/saprolitic horizons. The Block 1–2 corridor is the immediate focus, given its HREE-rich character and continuity; Block 3 adds leverage via the Mia REE MRE already in place.
How the deposit moves from here will largely be dependent on metallurgy and infill drilling, which will provide consistent leachability, scalable hydromet flowsheets, and enough drill density to uplift portions to Indicated. The published forward plan is appropriately calibrated to those aims.
Like all projects, whether it is a mineral or non-mineral project, a favourable logistical path (proximity to Esperance), and a current supported policy backdrop are going to be very constructive for Mount Ridley. As we have learnt over the last couple of years, clay-hosted critical-mineral systems live or die by extraction efficiency, impurity management, and unit costs. Those data points will ultimately define commerciality.
For investors tracking gallium exposure aligned with HREE/Sc optionality, this is now a defined system with scale and a clear work program to de-risk the flow sheet and grow resource confidence. DYOR, as the sector is just being thrown back into the spotlight. How long this remains in a favourable position is going to be tightly bound to the tenure of President Trump.
Market Influence
There is no doubt that the release of the resource has sparked great interest in the share price of MRD. As it's clearly shown in Figure 7, the market has taken notice, but the challenge for new investors and shareholders looking to top up is when to do that.
Figure 7: The share price chart for Mount Ridley as of 14th November 2025. (source: CommSec)
The Gallium "talk" is one that I am not really in tune with, as the main "producer" of the metal comes as a byproduct of the bauxite refinery. The recent news that the US government and the Australian government are in talks to support Alcoa to make a refinery that will treat their Gallium makes me think that there will be no space for the lone rangers, like Mount Ridley.
I would suggest reader DYOR and do it well :-)
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