Gorilla Gold Mines Eyes Comet Vale Restart With New Drilling Push

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Gorilla Gold Mines has cleared two milestones at its Comet Vale project on the same day. The company secured the final regulatory approval needed to begin underground development at its Sovereign deposit, and it published fresh metallurgical results showing 94.6% average gold recovery across three deposits at a deliberately coarse grind.

Both developments point the same direction: a project moving from planning toward production readiness. For ASX investors tracking development-stage gold juniors in the Western Australian Goldfields, this is the kind of pairing that matters. The permit removes the single largest non-technical barrier to underground mining at a deposit holding 410,000 ounces at 4.2 g/t Au, while the metallurgical work answers the processing question across the wider project, not just one lode.

Here is what the September 2026 disclosures actually confirm about where Gorilla Gold Mines sits on the development timeline and what the processing economics look like at Comet Vale. Not what might happen. What has been settled, and what still needs to be done.

Sovereign deposit clears its final underground permit as development momentum builds

Gorilla Gold Mines has received the last regulatory approval required to start underground mining at its Sovereign deposit, according to coverage from Australian Mining on 11 September 2026 citing CEO Charles Hughes, and by Kalkine Media on 10 September 2026 summarising the underlying ASX announcement. Underground development at Sovereign can now advance without further regulatory constraint.

That distinction matters, because underground permitting in Western Australia is not a single stamp. It is a staged pathway. A junior must lodge an approved Mining Proposal and Mine Closure Plan with the state regulator, covering geotechnical design, ventilation, ground support, water management and closure. It then needs specific approval of the underground mine design itself: decline alignment, stoping method, backfill strategy and emergency egress. That final design approval is the gate, and Sovereign has now passed it.

The staged nature of WA mining approvals, covering Mining Proposals, Mine Closure Plans, and underground design sign-off, means that each gate cleared by a junior removes a discrete category of sovereign risk from the project’s risk register.

The DMIRS Mining Development and Closure Proposals framework, which commenced in September 2025, consolidated the previously separate Mining Proposal and Mine Closure Plan into a single submission, streamlining the staged approval pathway that Sovereign has now fully navigated.

Sovereign is the primary source of Comet Vale’s high-grade history, having last been mined underground in 2020. It sits inside a project with more than 200,000 ounces of past production at grades above 20 g/t Au. The deposit itself holds 410,000 ounces at 4.2 g/t Au, part of a Comet Vale mineral resource estimate of 7.3 Mt at 3.7 g/t Au for 860,000 ounces. (Company materials show Sovereign at both 4.2 g/t and 4.3 g/t Au; the verified figure of 4.2 g/t Au is used here.)

CEO Charles Hughes on the milestone The company has stated that receiving the final underground permit at Sovereign is a major de-risking step, advanced alongside permitting and technical studies across its broader portfolio to reduce development risk and grow its resource pipeline.

What final permitting really unlocks is optionality. Gorilla can now award decline-development contracts, mobilise underground contractors and commit long-lead capital at Sovereign without a regulatory contingency hanging over the decision. That is the transition project-finance providers and toll-treatment partners watch for. It shifts the Sovereign conversation from “if” to “when.”

What 94.6% recovery at a coarse grind tells investors about Comet Vale’s processing economics

The metallurgical results published in September 2026 are best read as connected signals, not isolated percentages. Testing covered 18 representative samples drawn from three deposits, Lakeview, Sovereign and Cheer. The program returned 94.6% average total gold recovery over 48 hours, 42.3% average gravity recovery, and 90.1% recovery within eight hours, the last figure pointing to rapid leach kinetics.

The number that carries the most weight is the grind size. These recoveries were achieved at a coarse 150-micron grind, rather than the finer 75-106 micron range typical for the carbon-in-leach and carbon-in-pulp circuits used across the Goldfields.

Grinding is usually the single biggest energy consumer in a gold plant. Recovering more than 94% of the gold at a coarser grind means less mill power, fewer grinding stages, a simpler comminution circuit, and lower capital outlay to build it.

That single-deposit picture is not new; the multi-deposit program confirmed it. A first-pass Lakeview composite announced on 5 August 2025 returned 97.6% overall recovery and 55.6% gravity recovery from a head grade of roughly 4.9 g/t Au, with 94.9% achieved after just two hours of leaching. The September 2026 work extended that finding across three deposits rather than one.

The coarse-grind advantage Free-milling operations in the WA Goldfields typically target 90-95%+ recoveries at finer grinds of 75-106 microns. Achieving 94.6% at 150 microns places Comet Vale at the upper end of recovery performance for conventional ore.

For investors, processing economics feed directly into project-level valuation. Recoveries this strong at a coarse grind suggest Comet Vale, if developed, could run a simpler, lower-energy circuit than many WA peers. That is a genuine operating-cost advantage, and it would flow straight to project margins before any formal feasibility work begins. Gorilla has said the next test phase will evaluate how varying grind sizes affect recovery.

How the Sovereign permit and metallurgical results combine to define Gorilla’s development path

Taken together, the two milestones reduce two distinct categories of development risk at the same time. The permit opens the underground at Sovereign. The metallurgy across Lakeview, Sovereign and Cheer confirms the processing case, whether the company eventually pursues toll-treatment at nearby mills or a standalone plant. Historical Sovereign ore was toll-treated at the Greenfields and Lakewood mills, and Comet Vale sits roughly 100 km north of Kalgoorlie, keeping that milling option realistic.

For anyone assessing development-stage gold juniors, that convergence matters. Gorilla now has two of the three fundamental de-risking pillars confirmed at Comet Vale, permitting and processing amenability, with resource growth continuing across the wider North Kalgoorlie Hub of approximately 1.2 Moz at 3.7 g/t Au. That combination narrows the gap between a junior valuation and a development-ready re-rating.

The convergence of final permitting and multi-deposit metallurgical confirmation at Comet Vale places Gorilla in the category that project-finance providers and strategic acquirers have focused on most closely in 2026: buildable gold developers with a permitted deposit, a processing case, and a growing resource inventory.

What still needs to be confirmed

The September results are strong, but they are bench-scale. That comes with caveats worth holding onto.

• Grind-size variability testing: Gorilla’s next planned phase evaluates how coarser or finer grinds shift recovery, and results are not yet reported.
• Variability and pilot plant programs: Bench-scale figures can fall at full plant conditions, where grinding efficiency, slurry behaviour and leach times differ from the laboratory.
• Scoping or prefeasibility study: No formal study has yet been announced to convert these inputs into project-level economics.
• Toll-treatment negotiations: Access to nearby milling capacity remains an option to be commercially secured, not a done deal.

Gorilla’s stated strategy is to keep advancing permitting and technical studies across the broader portfolio to reduce development risk. The milestone cluster delivered in a single reporting period, regulatory clearance and processing confirmation across multiple deposits, is typically the kind that precedes scoping or prefeasibility work. That is where Comet Vale now sits on the timeline.

A scoping and prefeasibility study converts bench-scale metallurgy and resource estimates into project-level economics, including NPV, IRR and capital cost schedules, which is the formal step that would transform Comet Vale’s current inputs into a bankable investment thesis.

Comet Vale’s case sharpens, but the development calendar still has work to do

Twelve months on, Gorilla looks materially different. Sovereign was last mined underground in 2020; its final permit landed in September 2026. In the same window, the company confirmed a processing case across three deposits and continued building its resource base. That is the trajectory from an exploration-led junior toward a company with a permitted deposit, a demonstrated metallurgical case, and a growing inventory.

The resource anchors frame the scale: Sovereign at 410,000 oz at 4.2 g/t Au, Comet Vale at 860,000 oz at 3.7 g/t Au, and the North Kalgoorlie Hub at roughly 1.2 Moz at 3.7 g/t Au.

The next observable catalysts are clear enough: grind-size variability test results, any scoping or prefeasibility study announcement, and further permitting progress across the hub. Those outcomes, not the September 2026 disclosures alone, will determine whether this project reaches a production decision and on what timeline. Strong bench-scale metallurgy and a final underground permit are necessary conditions, not sufficient ones.

For investors exploring why development-stage milestones like final permitting and metallurgical confirmation do not always produce immediate share price re-ratings, our full explainer on junior mining stock valuations covers the structural discount dynamics that keep many development juniors below intrinsic value even after key de-risking steps.

This article is for informational purposes only and should not be considered financial advice. Investors should conduct their own research and consult with financial professionals before making investment decisions.

Past performance does not guarantee future results. Financial projections and development timelines are subject to market conditions, technical results and various risk factors, and forward-looking statements remain speculative and subject to change.