Why Radisson Mining’s O’Brien Hits Gold 83% of the Time at Depth

Eighty-three percent. That is how often Radisson Mining’s deep drill holes at the O’Brien project have hit gold at depths of one to two kilometres below the surface. In exploration terms, a number that high at that depth is not something that happens by accident.

So what does it actually take to hit gold that reliably, that deep, and why should you care?

The answer starts with geology. O’Brien sits in the Abitibi region of Quebec, one of the world’s most productive Archean gold districts, along a structure called the Cadillac-Larder Lake Break. The historic mine here closed in 1957, and it closed for economic reasons, not geological ones. Nobody had drilled at depth for roughly 70 years before Radisson started, not because the gold ran out but because the price and the equipment of the era made deeper mining uneconomic.

That distinction is the engine behind the entire current program.

After reading this, you will understand why the 83% hit rate is geologically credible, what the underground ramp being built at O’Brien is actually designed to learn, and how a sequence of staged resource updates connects to the conceptual 4 million-ounce target that has drawn so much attention to this junior.

Why 83% of deep drill holes hit gold at O’Brien

Put the number in operational terms first. Radisson has completed roughly 120-128 deep drill holes beneath and east of the historic mine, each reaching depths of about one to two kilometres. Of those, approximately 106 holes returned grades and widths consistent with the resource model. That is the 83%.

A number like that is not luck. It is a structural outcome of how the gold sits in the ground.

The mineralisation at O’Brien is hosted in what geologists call the PC formation: stacked, parallel quartz-sulphide gold veins with alteration envelopes that continue downward in a relatively consistent manner along the fault. When the veins repeat predictably at depth, and the host structure stays intact, a well-placed drill hole is far more likely to find them. Mineralisation has been confirmed to at least 1.9 kilometres vertical depth.

The grades the formation is producing help explain the attention it has attracted.

Record assay, July 2026 1,604 g/t Au over 1.0 metre, nested within a broader interval of 316 g/t Au over 5.1 metres. This was the highest assay result ever recorded at O’Brien.

Those are not typical numbers. In September 2026, eight deep holes drilled beneath the former mine all intersected gold, with a highlight intercept of 68.24 g/t Au over 6.2 metres and visible gold noted in the core.

How the hit rate is verified independently

Here is where the discipline behind the number matters. Radisson discloses every drill hole result as it becomes available, including the ones that miss. Because the company reports hole-numbering sequences continuously, a third-party observer can track the gaps in the sequence to identify failed holes and confirm the reported ratio independently.

That level of transparency is unusual among junior explorers, and it is cited in commentary as a genuine credibility signal. You are not being asked to take the hit rate on trust.

Thorough exploration due diligence on a junior at this stage means stress-testing each technical claim independently: verifying the disclosed hole-numbering sequences, checking the cut-off grade assumptions against comparable deposits, and benchmarking the resource model’s geological assumptions against the structural analogues the company cites.

A few operational features make the program efficient and the number robust:

• Every hole is disclosed, including unsuccessful ones, so the success rate can be checked externally.
• A successful intercept is defined as any result exceeding 3 g/t Au over core length, expected to dilute to above the 2.2 g/t Au resource cut-off.
• Drilling stays on the hanging wall (south) side of the fault, which supports better ground conditions and lower hole-loss risk.
• Up to 15 wedge holes can be drilled off a single pilot hole, enabling efficient cluster drilling from one setup.

What the hit rate tells you is that O’Brien is no longer a prospect being tested. It is a deposit being defined, and the geological setting gives a structural reason to expect continuity rather than merely hoping for it.

What the Abitibi geology tells us about O’Brien’s depth potential

Start with what is already proven, because that is where the depth case for O’Brien actually comes from.

The Cadillac-Larder Lake Break is a transcrustal shear zone, a long-lived fault that reaches deep into the crust and separates different volcanic and sedimentary rock packages. Structures like this focus the hydrothermal fluids that deposit gold, and along this break and its relatives, several deposits have demonstrated robust continuity to depths of 1-3 kilometres. LaRonde, Macassa, and Westwood are the documented examples.

The Cadillac-Larder Lake Break runs through one of the most mineralised corridors on the planet; the Abitibi greenstone belt has hosted successive generations of gold discovery since the early twentieth century, and its transcrustal fault architecture is the geological reason why depth continuity keeps appearing across structurally similar deposits.

Those are not exploration hopefuls. They are deposits that actually produced ore at depth, and that is why the 2.5-kilometre target at O’Brien is treated as a testable hypothesis rather than a promotional claim.

Now layer in O’Brien’s own history. The historic mine produced over 500,000 ounces at grades exceeding 15 g/t Au between 1926 and 1957, then closed on economics. When a mine closes because gold was cheap and equipment was primitive, vertical continuation becomes a logical exploration vector.

The extension logic runs like this: if mineralisation density equivalent to current drilling continues down to a two-kilometre floor, management estimates the resource at 3-4 million ounces. Extending drilling to 2.5 kilometres adds potential beyond that. The first drill hole placed 500 metres below the base of the historic mine returned an intercept of one ounce-equivalent over 8 metres, an early data point that the deeper thesis holds.

Here is how O’Brien currently compares to the belt’s proven deep producers.

The current compliant resource, released on 2 March 2026 and effective 31 January 2026, stands at 2.3 Moz combined: 0.63 Moz indicated at 5.59 g/t and 1.69 Moz inferred at 5.08 g/t. That estimate represented 8% growth in indicated ounces and 82% growth in inferred ounces versus the prior one.

A caveat worth holding onto The 4 million-ounce figure is a conceptual target, not a compliant resource. The verified number under NI 43-101 reporting standards is 2.3 Moz. Conservative analysts assign little or no value to exploration targets until they appear in compliant estimates.

The gap between that 2.3 Moz and the 4 Moz target is where the re-rating thesis lives. What the Abitibi analogy gives you is a geological basis for believing the gap can close, grounded in how this belt has actually behaved, not in wishful thinking.

What the underground ramp is actually designed to learn

Surface drilling has done its job. It has established grade and continuity across the deposit. But there are questions it structurally cannot answer, and those questions are what determine whether O’Brien becomes a mine rather than just a resource on paper.

Four of them matter most, and the underground exploration ramp is the instrument built to answer them:

1. What is the optimal mining method for these vein systems?
2. What dilution should be expected at stope scale, where mined grades can fall below drilled grades?
3. What are the actual ground conditions at depth?
4. What daily tonnage is sustainable?

To answer these, Radisson is building an exploration ramp to approximately 300 metres vertical depth, with ore drives through mineralised zones, underground drill platforms, and extraction of mineralised material for analysis. The program runs in parallel with the ongoing surface campaign.

The physical build-out involves real surface infrastructure:

• A water treatment facility
• A box cut
• A portal
• On-site mining equipment

Management is deliberate about one point: this is an exploration program, not a bulk sample. It is designed to answer technical questions, not to generate revenue or trigger a production decision at this stage. That framing matters, because it tells you what the ramp’s output actually is.

The Abitibi offers precedents for exactly this inflection point. Osisko Mining advanced Windfall from an exploration story to a large high-grade resource through a staged underground program, and Wesdome repositioned its Kiena complex by drilling below historic workings along a known structure. In both cases, underground exploration was the bridge between resource definition and a production decision.

Underground decline programs at the exploration stage share a common structural purpose: generating technical data on mining method, dilution, and ground conditions that surface drilling cannot produce, and the Sunday Creek decline in Victoria illustrates how a staged underground entry can reframe a deposit’s economic parameters before a formal feasibility commitment is made.

Timeline and permitting milestones

The sequence, funded by Agnico Eagle’s C$57.16 million investment that closed on 1 September 2026, runs like this:

Engineering and permitting commenced immediately after the September close. Portal construction is targeted for approximately mid-2027, subject to permitting and engineering proceeding as planned. The program is expected to span roughly 18 months once portal construction begins, putting ramp completion at approximately end-2028 or early 2029. The full Agnico Eagle-funded work program is characterised as a 2.5 to 3-year initiative, in place by 2029.

Quebec is generally a mining-friendly jurisdiction, but environmental review and community consultation can extend timelines, and permitting complexity tends to increase as an exploration ramp approaches production scale.

For you as an investor, the ramp’s meaningful output is not ounces in the ground. It is the set of answers, on mining method, dilution, ground conditions, and tonnage, that would set the parameters for any future feasibility study. These are the primary technical milestones to watch over the next two to three years.

Staged resource updates and what the 4 million-ounce target requires

Radisson is not building toward one definitive estimate. It is releasing the resource story as a sequence of evidence points, and understanding that cadence changes how you should read each announcement.

The next resource update is anticipated before year-end 2026, with a further update projected roughly nine months after that, likely in 2027. Management explicitly cautions against treating any single update as definitive.

What drives each update is step-out and wedge-hole results feeding revised geological models. The metric that signals rising confidence is growth in indicated ounces, the higher-confidence category. Recall that the 2026 estimate showed 8% growth in indicated ounces and 82% growth in inferred ounces.

The distinction between indicated and inferred ounces is the single most important number to track across successive O’Brien updates; resource classification categories determine which ounces can be included in economic studies, and the 82% inferred growth reported in the 2026 estimate means the majority of the current resource still carries the lower confidence designation that excludes it from feasibility-grade analysis.

Here is the resource picture with the growth context.

The 2026 estimate used a 2.2 g/t Au cut-off and a US$2,500/oz gold price assumption. The surface program supporting it runs to 140,000 metres, with eight rigs operating, a ninth imminent for the 2.5-kilometre hole, and drilling scheduled through mid-2027.

The distance from the compliant 2.3 Moz to the conceptual 4 Moz requires two things: continued high-grade intercepts at depth incorporated into future NI 43-101 estimates, and eventual underground drilling to convert inferred ounces into indicated. Neither is automatic.

Conservative analysts flag specific risks worth keeping in view:

• Inferred ounces do not convert to indicated at 100%.
• Narrow, high-grade vein systems are prone to dilution once mined underground, so mined grades can fall below drilled grades.
• Enterprise-value-per-ounce metrics can mislead when capital intensity and conversion rates are not yet defined.

There is a counterweight to the caution, and it carries genuine signal.

Strategic validation, not a guarantee Agnico Eagle, one of the world’s largest gold producers, invested C$57.16 million at C$1.07 per unit, taking approximately 10.45% of Radisson on a non-diluted basis (up to 14.9% partially diluted on warrant exercise, with warrants exercisable at C$1.39 for 60 months). The deal carries board nomination rights. A major producer committing capital is a credibility signal about geological potential, not a promise of the outcome.

The staged schedule tells you to treat each resource update as one data point in a multi-year series. The meaningful signals are indicated ounce growth and the underground program’s technical outputs, not the headline combined figure.

What comes next at O’Brien, and what investors should actually watch

You do not need to take a binary position on the 4 million-ounce target today. The practical question is whether each successive data point narrows the uncertainty between the current 2.3 Moz resource and that target.

The milestones arrive in a defined sequence:

1. Next resource update, anticipated before end-2026.
2. A subsequent update, roughly nine months later, likely in 2027.
3. Portal construction commencement, targeted for mid-2027.
4. Ramp operational, targeted for end-2028 or early 2029.

For context, 2027 is projected by management to be the most operationally active year to date, with eight rigs running, a ninth imminent, and portal construction expected to begin. The program is funded through mid-2027 with a likelihood of continuation. A July 2025 preliminary economic assessment described an 11-year mine life on a low-capex toll-milling approach, though no pre-feasibility study decision has been disclosed.

The signals that confirm or challenge the depth thesis

Three observable tests will tell you whether the thesis is tracking:

• Results from the ninth rig’s 2.5-kilometre deep hole.
• The rate at which inferred ounces convert to indicated across successive resource estimates.
• The underground program’s outputs on dilution and mineable widths.

Failure on any one of these does not collapse the thesis. It resets the timeline and changes the resource trajectory. That is the honest frame for a project at this stage.

The next 24 months are the most information-rich period in O’Brien’s modern history. The signals to watch are specific, dateable, and measurable, which means you can assess the story on evidence as it arrives rather than betting on the headline number.

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 are subject to market conditions and various risk factors, and forward-looking statements are speculative and subject to change based on market developments and company performance.