Diablo Resources Drills Utah Silver Prospect Showing Up to 3,043 g/t Ag at Surface
Key Takeaways
- Diablo Resources (ASX: DBO) has commenced maiden diamond drilling at the North Star Prospect within its Star Range Project in Utah's Frisco Mining District, marking the first subsurface test of the target.
- The initial program comprises approximately 1,000m across five diamond holes, targeting IP geophysical anomalies spatially coincident with surface rock chip samples grading up to 3,043 g/t silver and 1.37 g/t gold.
- Existing regulatory approvals permit up to 27 holes from 12 pads, giving Diablo significant runway to expand the program based on early results without requiring additional permitting.
- Silver, copper and antimony — all present in the North Star polymetallic system — are included on the US government's 2025 List of Critical Minerals, creating a supportive regulatory and commercial backdrop for domestic exploration.
- The broader Utah portfolio includes the South Star trend extended to over 3,000m strike length, an East Star copper anomaly, and the Horn Silver Project associated with a historic 17 Moz silver mine, with drill target definition now advancing at Horn Silver.
Maiden drilling begins at North Star as Diablo puts high-grade silver-antimony targets to the test
Surface sampling at the North Star Prospect has returned some striking numbers. Now Diablo Resources (ASX: DBO | OTCQB: DBORF) is taking the next step, putting drill bits in the ground for the first time to test what lies beneath.
The commencement of maiden diamond drilling at North Star marks a clear transition point for the company’s Star Range Project in Utah, USA. Months of surface geochemistry, geological mapping and IP geophysical surveys have defined the targets. The drill program, an initial ~1,000m across five diamond holes, is now putting those targets to a direct subsurface test for the first time.
The Star Range Project sits within the Frisco Mining District of southwestern Utah, an area with a well-documented history of base and precious metal mining. Existing regulatory approvals provide significant flexibility, with up to 27 holes from 12 pads permitted, giving Diablo room to expand the program as early results come in.
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What the drill holes are chasing — and why the grades stand out
The targets being drilled were defined through the integration of surface geochemistry, detailed geological mapping and induced polarisation (IP) geophysics. The surface results that anchored the target definition include the following selective rock chip samples from the North Star area:
- 3,043 g/t Ag (97.8 oz/t) and 1.37 g/t Au
- 1,592 g/t Ag (51.2 oz/t) and 0.7% Sb
- 2,311 g/t Ag (74.3 oz/t) and 0.4% Sb
- 1,243 g/t Ag (40.0 oz/t) and 0.2% Sb
It is important to note that these are selective point samples and are not considered representative of the average grade or width of the mineralised structures. They identify where high-grade mineralisation exists at surface, not what an entire deposit might average.
The drill program is specifically designed to test IP geophysical anomalies that are spatially coincident with these surface hits. The goal is to assess whether the silver-antimony-copper-gold (Ag-Sb-Cu-Au) polymetallic system extends to depth with meaningful scale, continuity and geometry.
| Prospect | Ag (g/t) | Au (g/t) | Sb (%) | Notes |
|---|---|---|---|---|
| North Star | 3,043 | 1.37 | — | Selective rock sample; not representative of average grade or width |
| North Star | 2,311 | — | 0.4% | Selective rock sample; not representative of average grade or width |
| North Star | 1,592 | — | 0.7% | Selective rock sample; not representative of average grade or width |
| North Star | 1,243 | — | 0.2% | Selective rock sample; not representative of average grade or width |
Understanding silver-antimony mineralisation — what investors should know
The mineralisation at North Star occurs as structurally controlled replacement-style deposits, specifically Carbonate Replacement Deposits (CRDs) and breccia-vein systems. In plain terms, a CRD forms when hot metal-rich fluids move through carbonate rock layers, replacing the original rock with ore minerals — often producing high-grade concentrations of silver, lead, zinc and copper. Breccia-vein systems are fractured rock zones where those same fluids deposit metals in cracks and cavities. Both settings are recognised globally as hosts to significant silver and polymetallic deposits.
The strategic timing matters here too. Silver, copper and antimony are all included on the United States’ final 2025 List of Critical Minerals. US government policy is actively supporting domestic exploration, permitting and development of these materials to strengthen supply chains. For a company like Diablo operating in Utah, this policy backdrop creates a more favourable regulatory and commercial environment than would otherwise exist.
A broader Utah portfolio taking shape — Star Range and Horn Silver
North Star is the first drill target in a considerably larger exploration pipeline. Regional work across Star Range is continuing alongside the drilling program, with several additional targets already defined:
- The South Star Ag-Sb prospective trend has been extended to more than 3,000m in strike length
- East Star has a defined copper-in-soil anomaly of approximately 400m
- The Horn Silver Project (associated with the 17 Moz Ag Horn Silver Mine) has returned high-grade silver, gold and copper results from recent first-pass reconnaissance sampling, with drill target definition now progressing
- Star Range and Horn Silver are located approximately 15km apart within the same Frisco Mining District, offering potential efficiencies across field logistics, contractors and permitting
Lyle Thorne, Chief Executive Officer
“Our U.S. exploration team is excited to have drilling underway at North Star. Star Range continues to demonstrate strong potential across multiple target zones, and this program will provide important subsurface data to guide the next phase of exploration. With drilling underway at Star Range and ownership consolidated at Horn Silver, Diablo is well positioned to accelerate exploration across both projects. This activity comes against a strengthening market backdrop for silver and copper and aligns with recent U.S. critical-minerals policy initiatives aimed at strengthening domestic supply chains and supporting exploration, permitting and development of strategic mineral resources. With multiple exploration programs now progressing across our Utah portfolio, we look forward to updating shareholders as drilling advances and results come to hand.”
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What comes next — near-term catalysts to watch
The near-term newsflow from Diablo is results-driven and sequenced across multiple workstreams. Investors should watch for:
- Progressive geological logging, sampling and assay submissions from the initial ~1,000m diamond drilling program at North Star
- Integration of drilling results into the North Star structural and geological model to sharpen understanding of the deposit geometry
- Follow-up drilling decisions based on initial results, with up to 27 approved holes from 12 pads providing substantial expansion runway
- Continued regional exploration and target ranking at South Star, East Star and other priority areas across the Star Range Project
- Advancement of maiden drill planning at Horn Silver alongside the exercise of the option over the patented claims, in accordance with the Option Agreement
Diablo enters this drilling phase with multiple active workstreams, exposure to three US-listed critical minerals, and a regulatory environment that is increasingly supportive of domestic exploration. The results from North Star will be the first real test of how the geology at depth measures up to what the surface work has suggested.
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