PolarX Reports Multiple Hyper-Grade Copper Intercepts from 2025 Drilling at Caribou Dome

2025 Drilling Results Highlight High-Grade Copper Potential

PolarX Limited (ASX:PXX) has announced strong assay results from its 2025 diamond drilling program at the Caribou Dome Copper Project, located within its broader Alaska Range Project in Alaska, USA. The program comprised nine holes totaling 2,133 metres, with eight holes intersecting hyper-grade copper mineralisation. Notable intercepts include 1.1 metres grading 13.23% copper and 14.91 g/t silver, and other intervals exceeding 10% copper, underscoring the high-grade nature of the deposit.

The drilling extended known mineralisation at depth, particularly at the Snow Gully area in the heart of Caribou Dome, and improved structural and geological understanding of the ore body. Mineralisation remains open both at depth and along strike, suggesting potential for further expansion.

New Mineralisation Style and Structural Insights

In addition to copper, the 2025 program identified a new style of gold and silver mineralisation in hole CD25-006, with 4.3 metres at 0.34 g/t gold and 1.4 g/t silver starting near surface. This mineralisation occurs within previously unmineralised shale and may represent a low-grade gold-bearing progression related to the hyper-grade copper massive sulphide system. Further investigation of this style is planned as part of ongoing core relogging and future drilling.

Detailed oriented core logging and structural interpretation have revealed minor fault offsets, generally less than 10 metres, which influence the continuity of mineralisation. These insights have informed the design of the upcoming 2026 drilling program, aiming to test down-dip extensions and lateral fault splays.

Upcoming 10,500m Drilling Program and Advanced Survey Techniques

PolarX plans to commence a significant 10,500-metre diamond drilling campaign at Caribou Dome starting in June 2026, with site preparations beginning in mid-May. The program will target multiple new extension zones identified through surface geochemical sampling and geophysical surveys.

Importantly, the company will employ downhole electromagnetic (EM) surveying throughout the drilling season to detect off-hole massive sulphide targets. This approach is supported by strong conductivity contrasts observed in drill core, which geophysical consultants consider effective for identifying additional mineralisation.

Context Within the Alaska Range Project and Joint Venture

Caribou Dome is a key component of PolarX’s Alaska Range Project, which also includes the Zackly Cu-Au-Ag skarn deposit and the Stellar copper-gold project. The Caribou Dome deposit currently holds a Mineral Resource estimate of 7.2 million tonnes at 3.1% copper and 6.5 g/t silver, updated in June 2023. A recent scoping study published in January 2024 projected a pre-tax net present value of A$625 million and an internal rate of return of 73.9%, based on copper and gold price assumptions.

PolarX’s Alaska Range Project is operated under an incorporated joint venture with Northern Star Resources Limited, which has earned a 15% interest through expenditure contributions. The parties recently approved a US$6.9 million exploration budget for 2026, focusing on the Caribou Dome drilling program and extending joint venture deadlines amid assay result delays. This agreement was detailed in a recent update on the joint venture’s exploration plans.

These developments position PolarX to potentially expand the resource base and advance the project’s economic assessment. The company’s integration of geological, geophysical, and drilling data aims to refine the 3D geological model and optimise future exploration efforts.

For further context on the joint venture arrangements and exploration budget, see the recent PolarX and Northern Star Approve $6.9M Drilling Budget, Extend JV Deadlines announcement.