Diablo Resources Ltd (ASX: DBO, OTCID: DBORF) is pleased to provide an exploration update for the Cupric Prospect, located within the Company's Horn Project in Utah, USA.
First-pass reconnaissance rock sampling, together with a review of historical exploration completed in the 1940s, has identified tungsten mineralisation associated with copper, gold and silver at Cupric, adding another critical mineral opportunity to the broader polymetallic Horn Project.
Key Highlights
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High-grade tungsten confirmed: Surface grab sampling at Cupric returned tungsten trioxide (WO₃) grades up to 0.37%, with six samples assaying over 0.1% WO₃, including 0.22% WO₃ and 0.17% WO₃ with 2.82 g/t Au.
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Strong copper-gold-silver association: Surface channel sampling returned 4.5m @ 1.26% Cu and 0.46 g/t Au, 2.6m @ 1.56% Cu (including 1.3m @ 0.12% WO₃), and 3.0m @ 1.00% Cu and 0.11 g/t Au.
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High-grade polymetallic results: Further grab samples from historical workings returned up to 12.5% Cu, 3.29 g/t Au and 398 g/t Ag.
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Historical underground access: Two adits developed during the 1940s provide access to the tungsten-mineralised system, with underground mapping and sampling underway ahead of the planned Q1 2027 drilling program.
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Expanded critical mineral opportunity: Cupric provides additional tungsten optionality within the broader Horn Project, complementing the existing high-grade Horn Mine, Imperial, Accrington, Washington and other emerging polymetallic targets.
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Strategic U.S. tungsten exposure: The United States remains heavily dependent on foreign tungsten supply, with tungsten designated as a U.S. critical mineral due to its importance in defence, manufacturing and advanced industrial applications.
CEO Commentary
Diablo Resources CEO Lyle Thorne commented:
"The Cupric results add another compelling dimension to the emerging polymetallic opportunity at the Horn Project. Despite evidence of past mining activity and historical evaluation work, the prospect has seen little modern exploration and remains largely underexplored. Our initial surface sampling has confirmed tungsten mineralisation associated with copper and gold in a skarn style setting.
Historical work completed in the 1940s led to the development of two adits that provide a unique opportunity to directly access the tungsten-mineralised system underground. Mapping and verification sampling will generate critical geological and geochemical data that will help prioritise targets and directly influence the next phase of exploration at Cupric.
Tungsten is a designated U.S. critical mineral with constrained domestic supply, adding strategic significance to the Project. While our focus remains on systematically advancing the highest-priority targets across Horn, Cupric represents another highly attractive opportunity within what is increasingly emerging as a large-scale polymetallic critical minerals district."
Cupric Adds to Horn's Polymetallic Potential
Since completing the acquisition of the consolidated Horn tenure package in early September, first-pass exploration has delivered exceptional regional silver, gold, copper, zinc and lead grades from surface rock sampling across multiple structural corridors, validating the polymetallic footprint of the Project and identifying new mineralised systems for follow-up exploration.
The results from Cupric add another dimension to the broader polymetallic potential, with first-pass sampling confirming tungsten mineralisation alongside copper and gold.
Cupric provides tungsten optionality within Diablo's existing Horn exploration strategy, complementing the broader critical mineral targets being advanced across the Project.
Diablo is continuing on-ground exploration at Cupric, including surface mapping, underground reconnaissance mapping and sampling. The use of UV blue light is aimed at assisting in the identification and mapping of potential tungsten-bearing zones.
Rock Sampling Results
A total of 27 samples were collected as first-pass reconnaissance surface grab and continuous channel samples across the Cupric Prospect.
The program was designed to verify historical surface results, with further surface sampling planned to better define the mineralised skarn at surface.
Significant grab sample results included:
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0.37% WO₃ from sample HS26-106
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0.22% WO₃ from sample HS26-71
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0.17% WO₃ and 2.82 g/t Au from HS26-107
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12.5% Cu, 3.29 g/t Au and 398 g/t Ag from HS26-90
Channel sampling also returned:
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4.5m @ 1.26% Cu, 0.46 g/t Au
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2.6m @ 1.56% Cu, including 1.3m @ 0.12% WO₃
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3.0m @ 1.00% Cu, 0.11 g/t Au
Grab rock samples from dump material also returned 11.9% Cu and 2.56 g/t Au, reinforcing the polymetallic nature of the system.
These results provide an initial basis for assessing the broader regional potential at Cupric and identifying areas for follow-up exploration.
Historical Exploration and Tungsten Potential
Exploration at the Cupric Prospect commenced in the early 1940s after scheelite-bearing skarn mineralisation was identified adjacent to a quartz monzonite intrusion.
Early geological investigations by the U.S. Geological Survey were followed by exploration programs undertaken by U.S. Vanadium Corporation and Homestake Mining Company, including surface trenching, mapping and sampling aimed at evaluating the tungsten potential of the system.
Further work was completed by the U.S. Bureau of Mines in conjunction with Desert Silver Mining Company during 1942–43, including the development of two adits to provide access to the mineralised zone and facilitate underground geological assessment and sampling.
This work identified three tungsten-bearing zones, Areas A–C, with the main focus being Area A.
Exploration activity largely ceased following the 1940s, leaving much of the system untested by modern exploration methods. The historical data has not yet been sufficiently verified under the JORC Code (2012).
Planned underground mapping and verification sampling will generate modern geological and geochemical data to directly inform ongoing exploration at Cupric.
Strategic Importance of Tungsten
Tungsten is a U.S. critical mineral, and the identification of tungsten mineralisation at Cupric adds another critical mineral target within Diablo's fully consolidated Horn Project tenure.
The United States is heavily reliant on foreign tungsten supply, with more than 50–60% of annual consumption imported, largely from China, leaving U.S. manufacturers, defence programs and advanced-materials industries exposed to potential supply-chain risk.
As a designated critical mineral, tungsten has no practical substitutes in several key applications, from armour-piercing alloys to high-temperature tooling, making secure domestic sources strategically important and increasingly sought after.
For Diablo, the recent Cupric results and historical underground work complement its existing silver, copper, gold and critical mineral targets, providing further optionality as the Company systematically advances exploration across the consolidated Horn Project.
Next Steps
Diablo will continue exploration activities at Cupric and across the broader Horn Project, including:
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Complete underground sampling, mapping and surveying of the historical adits.
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Continue mapping and sampling to better define existing anomalies and locate further mineralised zones, including further surface evaluation of historically defined areas.
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Collect representative samples for petrological examination.
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Review previous exploration for further indications of tungsten mineralised zones within the greater Horn Project.
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Integrate Cupric results into the broader evaluation and ranking of exploration targets across the Horn Project, in readiness for the Company's maiden drilling program scheduled for Q1 2027.
About us:
About the Company
Diablo Resources Limited (ASX: DBO | OTCID: DBORF)
The Horn Project acquisition delivers Diablo an 80% interest in a historically significant, district-scale polymetallic system comprising 101 patented and 101 unpatented claims in the Frisco Mining District, Utah. The acquisition consolidates ownership across a large, structurally controlled polymetallic system that historically produced 17 Moz of silver at 604 g/t Ag and hosts numerous high-grade silver, gold, copper targets.
The Horn Project is located approximately 20 km west of Milford in Beaver County, southwestern Utah, USA, within the historic Frisco Mining District covering approximately 13.2km2 and consists of 101 unpatented lode claims and 101 patented claims.
Diablo's Star Range Ag-Sb project lies approximately 15 km from the Horn Project. The proximity of the two projects provides the Company with a complementary portfolio of silver, antimony and copper exploration assets and the potential to leverage technical expertise, field logistics, contractors, permitting activities and future drilling programs across its Utah portfolio.
The combination of Horn and Star Range materially expands Diablo's exploration footprint in an established mining district and provides a portfolio containing both advanced drill targets and earlier stage regional opportunities.
Website: https://diabloresources.com.au/
Contact details:
Media Contact
Jane Morgan
Investor & Media Relations
Jane Morgan Management
E: [email protected]
Company Contact
Lyle Thorne
Chief Executive Officer
Diablo Resources Ltd
E: [email protected]
