PolarX Hits 24.8m at 9.8% Copper Near Surface and Extends Deposit 170m Deeper
Key Takeaways
- Hole CD26-007 returned 24.8m @ 9.8% Cu and 14.5g/t Ag from just 2.4m depth, including a 4.9m sub-interval at 13.6% Cu — grades that sit in a category rarely seen at any copper project globally.
- New drilling has extended known Caribou Dome mineralisation to approximately 500m below surface, a 170m depth extension beyond the current JORC Mineral Resource Estimate.
- Twin holes drilled adjacent to 1960s historical holes returned materially higher grades over wider intervals, raising the possibility that the existing 7.2Mt @ 3.1% Cu resource has been systematically understated.
- PolarX is planning a systematic re-assay of available historical pulps using modern four-acid digest and ICP-MS/ICP-OES methods, with verified results to feed into a future MRE update that could lift the average resource grade.
- The entire 2026 drill campaign is funded by Northern Star Resources under the Alaska Range JV earn-in, removing balance sheet risk from PolarX while approximately 1,700m of drilling remains this season.
Hyper-grade copper confirmed at depth as PolarX extends Caribou Dome mineralisation
The first assay results from PolarX’s 2026 diamond drilling campaign at Caribou Dome have delivered exceptional copper grades, with hole CD26-007 returning 24.8m @ 9.8% Cu and 14.5g/t Ag from 2.4m depth, including a high-grade sub-interval of 4.9m @ 13.6% Cu. These are grades that would be extraordinary at any copper project globally, and they come from near-surface mineralisation that drills out wide.
The campaign is fully funded by Northern Star Resources under the Alaska Range Joint Venture, with approximately 1,700m of planned drilling remaining this season. Alongside the standout intercept in CD26-007, hole CD26-004 returned 22.6m @ 8.1% Cu and 13.5g/t Ag from 3.7m, and new holes have extended known mineralisation to approximately 500m below surface, a 170m depth extension beyond the current Mineral Resource Estimate (MRE).
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Q1 FY27 drill results at a glance
The table below presents the key assay intercepts from the first five assayed holes of the 2026 campaign, sourced from Tables 1 and 2 in the announcement.
| Hole ID | From (m) | Interval (m) | True Width (m) | Copper (% Cu) | Silver (g/t Ag) |
|---|---|---|---|---|---|
| CD26-007 | 2.4 | 24.8 | 16.6 | 9.8% | 14.5 |
| incl. CD26-007 | 6.6 | 4.9 | 3.3 | 13.6% | 20.4 |
| and CD26-007 | 11.7 | 4.4 | 2.9 | 14.1% | 16.9 |
| CD26-004 | 3.7 | 22.6 | 16.0 | 8.1% | 13.5 |
| incl. CD26-004 | 11.1 | 5.8 | 4.1 | 12.4% | 21.3 |
| CD26-004 (HW) | 151.7 | 2.5 | 1.8 | 3.2% | 3.2 |
| CD26-003 | 453.7 | 0.3 | 0.2 | 3.5% | 4.0 |
| CD26-006 | 4.3 | 0.9 | 0.3 | 3.2% | 0.3 |
Key points from these results:
- Known mineralisation has been extended approximately 170m below the current MRE depth, with Caribou Dome now demonstrating potential to approximately 500m from surface
- CD26-004 ended in mineralisation, confirming high-grade copper at the northern hanging wall boundary
- Assays remain pending on visual sulphide intersections reported in the ASX release dated 2 September 2026
- PolarX plans a systematic re-assaying program of available historical pulps, which has the potential to lift the current average MRE grade
Why these grades matter — understanding copper resource economics
Most large-scale copper mines globally operate on ore grades below 1% Cu. That context makes Caribou Dome’s existing JORC resource grade of 3.1% Cu already exceptional. The 2026 drill intercepts approaching 10% Cu over intervals exceeding 20 metres from near-surface sit in a category rarely seen outside the highest-grade copper systems in the world.
In drilling, “true width” refers to the actual thickness of the mineralised zone as measured perpendicular to its orientation, rather than the length of core drilled through it. Wide, near-surface, high-grade intervals matter enormously for project economics: they reduce the volume of waste rock that needs to be moved relative to ore extracted (the strip ratio), and they lower the capital intensity of bringing a mine into production.
Caribou Dome’s existing scoping study, published 18 January 2024, projected a pre-tax NPV of A$625M (at a 7% discount rate) and an IRR of 73.9%, based on an assumed copper price of US$8,500/t and gold price of US$1,900/oz. Those figures pre-date today’s results and have not been updated. But they provide the baseline against which any future resource upgrade — driven by wider, higher-grade intercepts — would be measured.
Historical assays may have understated the deposit — re-assay program could be a re-rating catalyst
The most significant strategic signal from this announcement may not be the headline drill numbers themselves. It is the comparison between the 2026 twin holes and the historical results they were designed to replicate.
Holes CD26-004 and CD26-007 were drilled adjacent to historical holes DH40 and DH41, which were drilled between 1964 and 1970. The 2026 holes returned materially higher grades over wider intervals than the adjacent historical holes. The announcement notes this may have introduced a conservative bias and led to an underestimation of the overall grade of the deposit.
PolarX’s planned response is a systematic re-assaying program:
- Available historical sample pulps will be re-assayed using modern techniques, specifically four-acid digest and 41-element analysis by ICP-MS and ICP-OES at ALS Labs
- Modern assay methods are better suited to high-grade massive sulphide samples than the techniques available in the 1960s
- Where historical pulps are unavailable, further drilling will be planned to test those results
- Verified results will be incorporated into future MRE updates, with the potential to lift the current average grade of the existing resource
The current JORC resource, for context, stands at:
- Caribou Dome: 7.2Mt @ 3.1% Cu and 6.5g/t Ag — 224,375t contained copper
- Zackly: 4.0Mt @ 1.1% Cu, 1.6g/t Au, 12.6g/t Ag — 45,000t contained copper and 213,000oz contained gold
- Alaska Range combined: 269,000t contained copper
If re-assaying confirms a systematic upward grade bias in the historical data, the implication for the MRE and the project’s economic metrics could be material. No timing for an updated MRE has been disclosed in the announcement.
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Northern Star JV funding and what comes next
The 2026 drill campaign is running entirely on Northern Star’s funding, which removes financial execution risk from PolarX’s balance sheet for the current season.
Under the Alaska Range Joint Venture, Northern Star can earn up to 70% interest in the project over five years by contributing a total of up to US$39M. The first two annual contributions have already been received. The earn-in schedule, as disclosed in Table 5 of the announcement, is as follows:
- 2025: US$5M contributed — 15% earned
- 2026: US$6M contributed — 30% earned
- 2027: US$8M scheduled — 50% earned
- 2028: US$10M scheduled — 60% earned
- 2029: US$10M scheduled — 70% earned
PolarX currently holds beneficial interests of 60% in the Caribou Dome Project, 70% in the Stellar Project (which includes the Zackly deposit), and 68% in the Senator Project, via the Alaska Range Joint Venture.
For investors tracking this story, three catalysts are worth watching. First, the pending assay results on the visual sulphide intersections reported on 2 September 2026, which are targeting western extension targets prioritised this season. Second, the outcome of the historical pulp re-assay program, which has direct implications for the next MRE update. Third, the continuation of the ~1,700m of drilling still scheduled before the end of the 2026 season, which is targeting further depth and lateral extensions of the known mineralisation. No timing for an MRE update has been disclosed.
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