Caribou Dome Project
Alaska Range Limited owns the entire Alaska Range project and its known deposits. It is bounded by a comprehensive shareholder agreement between Northern Star Limited and PolarX whereby Northern Star may earn up to 70% of Alaska Range by providing up to US$39M cash funding. See our ownership page.
Caribou Dome Copper Project
(Alaska Range owns 94% earning to 100%)
Caribou Dome comprises 216 contiguous State Mining Claims located immediately adjacent to the Company’s Stellar Project. The claims cover a total area of 116 km².
The project is a core component of the broader Alaska Range Project, which is being advanced via a strategic US$39 million Joint Venture earn-in agreement with ASX gold giant Northern Star Resources.
The land package contains two key areas:
- Caribou Dome Deposit: It hosts an un-mined, high-grade JORC resource that remains open along strike and at depth.
And,
- Senator project: PolarX holds a 92% interest earning up to 100%).
- It features a large undrilled 5km-long copper-in-soil anomaly with surface rock chips grading up to 12.1% copper.
Ownership
For more information, structural terms of the Northern Star Joint Venture, and a complete diagram of mining claims, please refer to our Ownership Page
Location
The Caribou Dome Project is located approximately 250km northeast of Anchorage in Alaska, USA.
It is readily accessible by road; the Denali Highway passes within 20km of the project, where a purpose-built road provides direct access to the historical underground exploratory workings.
The Anchorage-Fairbanks railway line sits roughly 100km west of the project. Any potential concentrate or metal produced can be transported by road to the railway at Cantwell for direct shipment from the ports of Anchorage, Port Mackenzie, or Seward (accessible all year). Two nearby hunting lodges along the Denali Highway provide immediate accommodation, communications, and logistical support.
History
Copper mineralisation was first discovered at Caribou Dome in 1963. Between 1964 and 1970, 95 diamond holes were completed to delineate nine lenses of volcanic sediment-hosted copper/silver mineralisation across an 800m strike.
PolarX commenced modern exploration in 2015, publishing a maiden resource in April 2017. This resource was more than doubled on 13 June 2023 following extensive core drilling, structural interpretation, and updated metallurgical test work. Continuous diamond drilling programs since late 2024 have consistently validated the high-grade profile and successfully proven that massive sulphide lenses extend well below historical limits.
Technical Review & Exploration Results
Caribou Dome occurs within deformed lenses of fine-grained massive sulphides (chalcopyrite and pyrite) associated with calcareous volcanic argillites. The mineralised system has been affected by two or more distinct phases of folding and faulting, extending from the surface to depths well below the current 300m resource boundary.
High-Priority Targets
- System Scale: Active targets span a mineralised strike of more than 15km.
- Snow Gully Zone: Located at the heart of Caribou Dome, drilling has identified a brand-new style of gold-silver mineralisation (e.g., 4.3m @ 0.34g/t Au & 1.4g/t Ag in hole CD25-006) which points to an extensive, previously overlooked intrusive feeder system.
Core Drilling Highlights
Recent asset-testing campaigns have delivered “hyper-grade” copper intercepts at depth. Key recent drill
holes include:
- CD25-005: 18.0m @ 2.84% Cu and 3.65g/t Ag from 99.4m (including 8.5m @ 5.98% Cu).
- CD25-009: 5.3m @ 6.12% Cu from 239.9m (including 2.5m @ 10.82% Cu and 17.68g/t Ag, located 282m below surface).
- CD25-004: 11.3m @ 3.49% Cu from 74.6m.
- Historical Lens 4 High: 51.1m @ 5.3% Cu from 4.4m.
2026 Exploration Strategy
A US$6.9 (~A$8.5) million program budget has been approved and has already been funded by Northern Star Resources. A massive 10,500-metre drilling campaign is scheduled to commence in June 2026. Exploration will utilise downhole electromagnetic (EM) surveys to directly map and isolate deep, massive sulphide conductors across the property.
Mineral Resources
The JORC-compliant Mineral Resource Estimate (MRE) for Caribou Dome stands at 7.2 Million Tonnes (Mt) grading 3.1% Copper and 6.5 g/t Silver. This yields 224,375 tonnes of contained copper and 1.5 Million Ounces (Moz) of contained silver.
2023 Caribou Dome Mineral Resource estimation summary table.
| Category | Tonnes (Mt) | Cu (%) | Cu (t) | Ag (g/t) | Ag (oz) |
| Measured | 1.0 | 3.9 | 39,800 | 8.6 | 284,000 |
| Indicated | 3.2 | 3.3 | 105,175 | 6.5 | 662,800 |
| Inferred | 3.0 | 2.6 | 79,400 | 5.7 | 552,000 |
| Total | 7.2 | 3.1 | 224,375 | 6.5 | 1,498,800 |
Note: Reported at a 0.5% Cu cut-off grade. Numbers may not sum precisely due to rounding. In-situ resources assume 100% metallurgical recovery. [1, 2]
The revised Mineral Resource Estimate for Caribou Dome has a copper metal content of 224,375 tonnes. This was 2.6 times greater than the 2017 Mineral Resource Estimate of 2.8Mt at 3.1% Cu with contained copper metal of 86,000 tonnes (also using a 0.5% Cu cut-off, see ASX announcement 5 April 2017).
This substantial resource increase is expected to commensurately enhance PolarX’s recent Positive Mining Scoping Study on its Alaska Range Project as announced to ASX on 17 October 2022.
Silver has also new been estimated for the first time at Caribou Dome with a contained silver metal content of 1.5 Moz within the 0.5% copper cut-off envelope. The silver content is expected to further enhance the updated Scoping Study.
Metallurgy & Project Economics
An updated Project Scoping Study completed in 2024 evaluated a combined mining approach for the Alaska Range Project. The strategy based on the resources drilled to that point envisaged a centralised, conventional 750ktpa flotation mill processing Caribou Dome’s open-pit ore for the first 5 years, followed by 4.5 years of underground mining at the adjacent Zackly copper-gold-silver deposit.
- Enhanced Recoveries: Metallurgical optimisation work conducted by Ausenco Engineering Canada has successfully bumped copper recoveries up to 87.9%, yielding a clean, commercial concentrate grading 21.7% Cu.
- Robust Return Metrics based on conservative price assumptions, the 2024 study outlines a pre-tax NPV of A$625 million, an internal rate of return (IRR) of 74%, and a rapid 1.6-year capital payback window.
Recent surges in global spot copper and gold pricing present massive economic upside to these 2024 baselines.
| Revenue US$1,491 A$2,294 ($0.65) |
Total EBITDA US$825 M A$1,269 M |
| C1 Cash Cost US$1.36 / lb A$2.10 / lb Cash costs with Au and Ag credits |
Operating Margin 55% EBITA/ Revenue |
| Average Annual Free Cash Flow US$78 M A$120 M Post construction |
Initial Capital Required US$147 M A$226 M |
| NPV 7 Pre-Tax US$406M A$625 M |
IRR Pre-tax 73.9% |
| Payback 1.6 Years Post construction |
Mine Life 9.5 Years |
Senator Project
(Alaska Range Owns 90% earning to 100%)
The Senator Project represents a major regional exploration asset within the broader Alaska Range Project footprint, sitting strategically as a geographic and structural link between the high-grade Caribou Dome Volcanogenic Massive Sulphide (VMS) deposit and the Zackly copper-gold-silver skarn deposit.
Strategic & Geological Profile
- Footprint Scale: Features an extensive structural corridor tracking a massive 5km-long copper-in-soil anomaly accompanied by outcropping surface gossans.
- Surface Mineralisation: Surface rock-chip sampling programs originally returned spectacular, ultra-high-grade values of up to 12.1% copper. Recent property-wide sampling continues to yield consistent results across the trend, confirming up to 2.85% copper and 0.30g/t gold at surface.
