Diablo Resources (ASX:DBO) consolidates Utah exploration momentum as copper drilling concludes and silver antimony targets evolve

Diablo Resources continues to advance its United States critical minerals portfolio through a structured and technically disciplined exploration program, utilising its highly experienced in-country technical team.

Exploration recently completed includes reverse circulation drilling at the Phoenix Copper Project and systematic surface exploration progressing at the Star Range Silver Antimony Project, with both projects occurring in Utah, a mining friendly state.

Activities are concentrated within established mining districts and are supported by an expanding dataset comprising drilling, surface geochemistry, geological mapping and geophysical interpretation, with current work focused on refining geological understanding and target definition in readiness for drill planning.

Lyle Thorne, Chief Executive Officer, addresses key investor considerations arising from the current phase of exploration across both projects.

What has been completed at the Phoenix Copper Project and what work remains outstanding before results can be assessed?

Our second program of reverse circulation drilling for 2025 has been completed at the Phoenix Copper Project across the Fair Dinkum and Philadelphia Prospects, with a total of 10 holes drilled for 906 m using a track mounted rig. Drill samples have been submitted to the laboratory with assay results pending.

The completed program was designed to test priority structural positions identified through surface mapping, geochemistry and historical data, while also providing information on mineralisation geometry and continuity.

Once assays are received, the focus will shift to integrating the results into existing geological models to refine interpretations of mineralisation controls, orientation and scale, which will then inform the sequencing of follow up work.

Drilling at the Phoenix Copper Project has been completed across the Fair Dinkum and Philadelphia Prospects, with 10 holes for 906 m drilled and samples submitted for laboratory analysis, providing the data required to refine geological models and assess mineralisation continuity.

How does the Fair Dinkum target fit within the broader geological context of the Lisbon Valley copper district?

The Fair Dinkum Prospect is located within a well established geological corridor of the Lisbon Valley copper district and sits approximately 5 km southeast of the Lone Wolf Deposit and approximately 2 km east of the Flying Diamond Deposit, positioning it along the projected trend of the Flying Diamond Fault, a structure known to host copper mineralisation in the region.

Drilling targeted the down dip extension of mapped surface copper mineralisation, which had previously been supported by 13 rock grab samples returning peak results of 2.76% Cu and 92 g/t Ag, with an average grade of 1.12% Cu and 7 of the 13 samples grading above 1% Cu.

The program was designed to test the mineralised horizon at depth and establish continuity along strike, as a first pass step to obtain an initial understanding of continuity and scale.

The Fair Dinkum Prospect occupies a structurally favourable position along the projected Flying Diamond Fault mineralised trend, supported by surface sampling that returned peak grades of 2.76% Cu and an average grade of 1.12% Cu across multiple samples exceeding 1% Cu.

What is the current level of technical confidence at the Philadelphia Prospect following recent drilling and historical work?

The Philadelphia Prospect is centred on historical copper workings dating back to the early 1900s and hosts mineralisation along a sub vertical fault system within the Lower Hermosa Formation, which has been confirmed through surface mapping, sampling and drilling.

Prior surface sampling returned multiple copper intervals including 6 m at 2.13% Cu with 1 m at 7.16% Cu, 3 m at 1.28% Cu and 10 m at 0.55% Cu, alongside rock samples grading up to 45.7% Cu.

Scout drilling completed earlier this year returned 10.5 m at 1.02% Cu including 1.5 m at 3.99% Cu, as well as 1.5 m at 1.33% Cu from 32 m downhole, and the most recent program added a further 2 holes for 184 m to test both depth and strike continuity.

Mineralisation remains open along strike and at depth, with pending assays required to assess continuity beyond previously tested zones and to support further geological interpretation.

What progress has been made at the Star Range Silver Antimony Project and what evidence supports further advancement?

At the Star Range Silver Antimony Project, surface exploration has continued to advance through an expanded reconnaissance rock sampling program, with 65 samples currently at the laboratory for analysis, building on an earlier phase of work that identified multiple high grade silver-copper antimony vein breccia systems.

Initial surface sampling by the exploration team returned peak results of 3,043 g/t Ag and 0.7% Sb across several prospect areas including North Star, South Star and Silver Gulch, consistent with historical sampling that reported bonanza silver grades up to 8,760 g/t Ag with greater than 1% Sb.

Geological mapping, geochemical characterisation and interpretation of data from a recently completed airborne magnetic survey are being integrated to refine targeting, validate structural controls and support the identification of drill ready zones.

Surface exploration at the Star Range Silver Antimony Project has confirmed multiple high grade vein breccia systems, with sampling returning silver grades up to 3,043 g/t and antimony up to 0.7%, consistent with historical bonanza grade results and supporting a coherent structurally controlled system.

How does the current United States critical minerals policy environment relate to the company’s portfolio without assuming future outcomes?

Copper and silver have been included for the first time on the United States Geological Survey Final 2025 Critical Minerals List, reflecting their recognised importance to electrification, renewable energy, infrastructure, defence and national security, while antimony remains globally supply constrained.

In parallel, the United States Government has applied the FAST 41 federal permitting transparency framework to key domestic mineral projects, including the Lisbon Valley Copper Mine expansion and also announced US$355 m in Department of Energy funding initiatives aimed at supporting domestic critical minerals exploration, production and processing.

These developments provide broader policy context for United States based copper, silver and antimony projects, including those held by the Company, without implying any specific regulatory, funding or development outcomes.

2026 outlook and execution focus

Lyle Thorne Diablo Resources

Chief Executive Officer, indicates that the Company enters 2026 with a defined technical workflow across both the Phoenix Copper Project and the Star Range Silver Antimony Project, underpinned by completed drilling, expanded surface sampling and recently acquired geophysical datasets.

With drilling and sampling programs completed and assays pending, the focus remains on disciplined data integration, geological interpretation and target refinement to support technically robust exploration decisions into 2026.

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