Copper One Resources has announced high copper concentrations from underground sampling at its Majuba Hill Copper-Silver-Gold Project in Pershing County, Nevada, in the United States.
The results come from a recent breccia mapping programme conducted within the historic Middle Adit.
Sample MHR-793 returned assay values of 10.5 per cent copper and 188 grams per tonne silver, marking one of the strongest grades reported from the site to date.
The samples were collected during the 2026 spring mapping campaign to examine breccia textures across 15 separate locations.
This work builds on earlier surface sampling from 2016, when eight rock samples collected from the area returned copper values ranging from 0.39 per cent to 1.6 per cent.
Copper One noted that sample MHR-793, together with the adjacent sample MHR-794, contained oxide copper identified as azurite within intrusive breccias hosted in a tourmaline matrix.
The company said this mineral association is consistent with the broader breccia system already mapped at surface.
Underground mapping within the Middle Adit also confirmed breccia characteristics previously identified through surface mapping.
In addition, the work exposed a known north-east-trending breccia system and revealed a previously under-reported north-north-west-trending breccia corridor, giving the company a more detailed picture of the structures controlling mineralisation at the site.
Copper One said this improved geological understanding is expected to strengthen its 2026 drill programme by helping refine structural targets and identifying new areas where high-grade copper mineralisation could occur.
The company also pointed to earlier drilling success at Majuba Hill.
Prior drill holes have intersected copper and silver-bearing hydrothermal-magmatic breccias, including hole MHB-2, which returned 44.5 metres grading 1.41 per cent copper and 97.6 g/t silver.
Another hole, MHB-32, reported 115.7 metres at 0.33 per cent copper and 16.97 g/t silver, including a higher-grade interval of 12.2 metres at 1.36 per cent copper and 13.33 g/t silver.
The Majuba Hill project covers approximately 9,684 acres and is located roughly 113km south-west of Winnemucca, Nevada, and 251km north-east of Reno.
The site is accessible via county roads and is supported by existing infrastructure, including roads, power, water and access to skilled personnel.
Copper One president and CEO David Greenway said: “Majuba Hill has entered an exciting new phase with drilling now under way on our initial ExploreTech AI-designed core hole.
“Recent underground mapping within the historic Middle Adit has strengthened our geological model by confirming breccia-hosted copper mineralisation and its relationship to surface structures.”
The underground results follow last month’s announcement that the company had begun drilling its first diamond drill core hole designed using artificial intelligence at the Majuba Hill project, part of a broader push by Copper One to apply AI-driven exploration tools to identify new targets across the site.
With drilling now underway and updated structural interpretations in hand, the company said it expects the current programme to further test the extent and grade of copper-silver mineralisation at Majuba Hill in the coming months.
