Capricorn Metals (ASX: CMM) Lifts Mt Gibson Gold Resource to 895Koz, Strengthening Underground Growth Outlook

Key Highlights:

• Underground resource at Orion South rises 31% to 9.5Mt at 2.9g/t gold for 895,000 ounces.
• Over 13,000 metres of drilling completed since July 2025. 
• One-third of underground ounces now classified as Indicated, paving way for Pre-Feasibility work.
• Mineralisation remains open at depth and along strike, with strong continuity. 
• Executive Chairman Mark Clark says results validate Mt Gibson as a “long-life open pit and underground operation.”
   

Gold producer Capricorn Metals Ltd (ASX: CMM) has announced a major increase in underground resources at its Mt Gibson Gold Project in Western Australia, confirming the project’s potential to evolve into a long-life, dual open pit and underground mining operation.

The updated Mineral Resource Estimate (MRE) for the Orion South deposit now totals 9.5 million tonnes at 2.9 grams per tonne (g/t) gold for 895,000 ounces, marking a 31% uplift from the July 2025 maiden underground estimate.

The increase follows 13,400 metres of diamond drilling focused on defining extensions and upgrading resource classification across the Orion South zone, located directly beneath the existing open pit design.

High-Grade Results Highlight Continuity and Scale

Capricorn’s latest drill results have continued to return strong gold grades, demonstrating excellent geological continuity at depth. Intercepts include:

• 3.0 metres at 46.28g/t gold from 186m,
• 4.9 metres at 28.11g/t gold from 420m, 
• 24.4 metres at 3.69g/t gold from 469m, and 
• 16.0 metres at 5.21g/t gold from 43m.
  
   

The company said the underground mineralisation extends more than 220 metres below the existing pit design, with the system remaining open both down-dip and along strike.

Executive Chairman Mark Clark said the rapid expansion underscores the scale of opportunity emerging at Mt Gibson.

“Increasing the Orion South underground resource by over 30% to 895,000 ounces in less than four months since the maiden estimate highlights the deposit’s strength and continuity,” Clark said. “Our objective is to grow the resource base, define reserves, and demonstrate that Mt Gibson can sustain a long-life open pit and underground operation.”

Confidence Builds with Indicated Classification

Of the total underground resource, 297,000 ounces (33%) have now been upgraded to the Indicated category, providing a strong foundation for mine planning and future reserve conversion.

Capricorn said ongoing drilling aims to improve classification and extend mineralised envelopes to support a Pre-Feasibility Study (PFS) and a maiden Underground Ore Reserve.

The company’s exploration focus will next expand to the Lexington and Hornet zones, which sit along the same 8-kilometre mineralised corridor and show similar geological characteristics.

Strong Grade Density and Open Growth Potential

Capricorn highlighted that the Orion South underground zone averages 5,400 ounces per vertical metre across the 100-metre section below the open pit design — a strong indicator of consistent grade density.

Currently, the resource footprint covers only 1.2 kilometres of strike, within a much larger 8-kilometre gold-bearing trend, providing significant upside for future growth.

Clark said this early success was key to the company’s strategy.

“We see excellent potential for continued expansion along strike and at depth. The consistency of results and increasing resource quality provide a solid platform for long-term mine development.”

Project Context and Future Plans

Located about 280 kilometres northeast of Perth, the Mt Gibson Gold Project lies in the well-endowed Murchison region of Western Australia. The project benefits from extensive historical infrastructure, including proximity to the Great Northern Highway.

Gold was previously mined at Mt Gibson between 1986 and 1999, yielding over 868,000 ounces before operations ceased due to lower gold prices. Capricorn’s modern exploration efforts have since revitalised the region, revealing multiple high-grade underground shoots below historic workings.

The deposit features steeply dipping lodes up to 50 metres wide, with mineralisation open beyond 950 metres depth — typical of Western Australian Archean gold systems.

Capricorn is currently advancing geotechnical, metallurgical, and hydrogeological studies to support detailed mining and processing evaluations. A trade-off study assessing the interface between open pit and underground mining is also underway, with results expected by mid-2026.

Analyst and Market Perspective

Market analysts view Capricorn’s underground growth as a strong signal of resource scalability and operational longevity. The company’s total group resource now exceeds 6.83 million ounces, with potential for further upside across both Mt Gibson and Karlawinda.

Given the current gold price of around A$3,700 per ounce, Capricorn’s integrated open pit and underground strategy positions it as one of Australia’s most cost-efficient and growth-focused mid-tier producers.

Next Steps

Capricorn’s immediate work programs include:

• Continued drilling at Orion South to expand and upgrade resources.
• Commencing exploration at Lexington and Hornet. 
• Advancing the PFS and mining interface studies. 
• Ongoing technical analysis to support future development and reserve conversion.
  
   

“The momentum we’ve built at Mt Gibson is transformative,” Clark said. “Each phase of drilling continues to demonstrate the scale and quality of this gold system, underpinning Capricorn’s next phase of growth.”

Investor Takeaways

Resource Growth Momentum:

Mt Gibson underground resource increased 31% in four months, now at 895Koz — with further expansion drilling underway.

High-Grade Consistency:

Significant gold grades up to 46.28g/t confirm the project’s strong geological continuity and scalability.

Path to Long-Life Operation:

Capricorn targets dual open pit and underground development supported by ongoing feasibility and reserve work.

At the time of writing this article, CMM shares were trading at $ A 14.28, up by 4.31%