Drilling completed at Phoenix, surface sampling and geophysical interpretation advancing at Star Range underpin sustained exploration momentum across Diablo’s U.S Critical Minerals portfolio.
HIGHLIGHTS
PHOENIX COPPER PROJECT
-
RC drilling has been completed at the Phoenix Copper Project in southeast Utah, across two priority target areas;
-
Drill samples have been submitted to the laboratory, with assay results pending.
-
Drilling at the Fair Dinkum target, located ~5km southeast of the Lone Wolf Deposit (Lisbon Valley Copper Company, a 60Mt resource containing 12.1Kt of recoverable copper) and ~2km east of the Flying Diamond Deposit.
-
Drilling at the Philadelphia Prospect followed up first pass wide spaced drilling that returned 10.5m @ 1.02% Cu incl. 1.5m @ 3.99% Cu from 36.5m in PHIL 25-107.
STAR RANGE SILVER-ANTIMONY PROJECT
-
Surface sampling program expanded, with 65 rock samples submitted for analysis to extend and refine high-grade silver-antimony target zones.
-
Sampling builds on previously reported high-grade silver to 3,043 g/t (97.8 oz) and antimony to 0.7%.
-
Early exploration continues to validate a coherent, structurally controlled polymetallic system, supported by high-grade assay and historical workings.
-
Geological targeting and interpretation underway using data from the recently completed airborne magnetic survey.
-
Ongoing geological mapping and geochemical characterisation to support progression toward identifying further drill ready targets.
Diablo Resources Limited (ASX: DBO; OTC: DBORF) (“Diablo” or the “Company”) is pleased to provide an update on the advancing exploration programs across its 100% owned critical minerals projects in Utah, USA, a Tier-1 Mining Jurisdiction. Drilling has been completed at the Phoenix Copper Project, while surface sampling and geophysical interpretation continue to advance high-grade silver-antimony targets at the Star Range Project. The Company is also actively reviewing additional US critical minerals opportunities leveraging its in-country expertise.
CEO COMMENTARY
CEO, Lyle Thorne commented:
“The Company has had an active and rewarding 2025, with exploration firmly focused on advancing prospects within our portfolio to take full advantage of the current US administration’s drive to secure domestic critical minerals supply. This approach returned exciting results at our two key projects delivering priority targets to progress in 2026.
At our Phoenix Copper Project, early surface geochemical sampling and mapping provided strong encouragement to drill high grade outcropping copper targets at several areas, including Fair Dinkum and Philadelphia, where geological similarities to known copper deposits are compelling. We completed our maiden drill program at Phoenix in August, returning shallow high grade copper intercepts from wide spaced drilling at Philadelphia. This gave us sound momentum to undertake a second program, recently completed, at both Philadelphia and our priority Fair Dinkum Target located along strike from known copper deposits, with assay results awaited.
Our ongoing review of other opportunities in the US critical minerals space led to the acquisition of the Star Range Silver-Antimony Project during the year. Defined by numerous old workings, outcropping silver-antimony mineralisation and a rich mining history, the project has already delivered high grade results from several prospect areas. On ground exploration also led to a meaningful expansion of tenure covering mineralised outcrop and extensions to known mineralised trends.
Results from the recent geophysical and geochemical programs are pending with an anticipation of further delineating exciting targets for follow-up. We plan to quickly outline drill targets and get the drill bit turning in 2026.
We also listed on the US OTC market this year which allows U.S. investors to better appreciate the value of our near-mine, high-quality exploration assets. In line with this strategy, we also appointed a US-based Non-Executive Director to strengthen our domestic presence, positioning the Company to explore additional promising U.S. opportunities, including potential acquisitions, mergers, joint ventures, and other strategic corporate initiatives.
All of our efforts in 2025 have provided a strong foundation for ongoing exploration success at both projects into 2026. Our highly experienced US-based team provide a definitive in-country advantage for effective completion of well-planned exploration programs, and is committed to deliver shareholder value through continued systematic, focused and efficient exploration.
On a personal note, I would like to thank the DBO Board, our US exploration team and shareholders for their support and encouragement throughout the year and look forward to an exciting and rewarding 2026.”
NEXT STEPS
With exploration results awaited from both the Phoenix and Star Range Prospects, Diablo has a well-defined workflow to rapidly advance geological understanding and delineate potential mineralised zones.
Phoenix Copper Project
-
Interpret assays and update geological models to refine understanding of mineralisation controls, continuity, and scale.
-
Fair Dinkum target, located ~5km southeast of the Lone Wolf Deposit (Lisbon Valley Copper Company, a 60Mt resource containing 12.1Kt of recoverable copper) and ~2km east of the Flying Diamond Deposit. Drilling focused on initial drill testing outcropping of copper mineralisation, with peak Cu to 2.76% along the Flying Diamond fault.
-
Drilling at the Philadelphia Prospect followed up first pass wide spaced drilling that returned 10.5m @ 1.02% Cu incl. 1.5m @ 3.99% Cu from 36.5m in PHIL 25-107.
-
-
Planned follow-up exploration, including further sampling, mapping, geophysics and drilling programs.
Star Range Silver-Antimony Project
-
Await results from extensional surface geochemical sampling of outcropping high-grade silver-antimony-copper mineralised zones, aimed at complementing high grade results including silver to 3,043 g/t and antimony to 0.7% and historical peak results of 8,670 g/t Ag and +1% Sb.
-
Continue surface mapping and sampling, with an impetus to locate and extend further mineralised zones.
-
Integrate geophysical interpretations and modelling from the recently completed aeromagnetic survey into the project exploration database to advance drill target planning for 2026.
-
Continued review at a local level to identify opportunities and expand tenure over priority exploration areas.
Domestic Critical Minerals Opportunities
The U.S. Geological Survey’s Final 2025 Critical Minerals List (November 2025) included copper and silver for the first time, recognising their increasing importance to electrification, renewable energy, infrastructure, defence, and national security.
In parallel, the U.S. Government has:
-
applied the FAST-41 federal permitting transparency framework to the nearby Lisbon Valley Copper Mine expansion; and
-
announced US$355m in new Department of Energy critical minerals funding initiatives supporting domestic critical minerals exploration, production and processing.
Together, this evolving policy landscape materially enhances the strategic significance of Diablo’s U.S. copper portfolio. The Company will continue to actively evaluate additional U.S. critical mineral opportunities, consistent with its strategy to build a diversified U.S.-focused portfolio.
About us:
About Diablo Resources
PHOENIX COPPER PROJECT
OVERVIEW
The Phoenix Copper Project is located ~70km southwest of Moab, Utah, USA and comprises 315 unpatented lode claims covering ~6,300 acres, held within two claim blocks along strike from Lisbon Valley Copper Mine.
The Project is situated within an established Tier-1 U.S. copper jurisdiction with year-round access via sealed and well-maintained gravel roads, and proximity to existing mining infrastructure.
DRILLING
A track-mounted reverse circulation (“RC”) drill rig completed 10 holes for 906m at the Fair Dinkum and Philadelphia Prospects. Drill samples have been submitted to the laboratory with results pending.
FAIR DINKUM PROSPECT
The Fair Dinkum Prospect is located to the southeast of the Lone Wolf and Flying Diamond Deposits and sits along the projected trend of the Flying Diamond Fault, a known structure that hosts copper mineralisation.
A total of 8 holes for 722m targeted the highly prospective Flying Diamond Fault zone that has been traced for ~1,000m within the northern portion of the Stateline Claim Block.
Drilling focused on the down dip extension of the mapped surface copper mineralisation where 13 rock grab samples returned significant Cu and Ag results:
-
Peak results to 2.76% Cu and 92 g/t Ag
-
Average grade of 1.12% Cu with a minimum of 0.19% Cu
-
7 of the 13 samples collected returned >1% Cu
Historical drill pads dating 2005–2006 were identified at the northern extent of the target; however, no verifiable drilling data is available.
PHILADELPHIA PROSPECT
The Philadelphia Prospect is centered on historical copper workings dating to the early 1900s and hosts mineralisation along a sub-vertical fault system within the Lower Hermosa Formation.
Surface sampling earlier this year returned significant copper results, including:
-
6m @ 2.13% Cu (incl. 1m @ 7.16% Cu)
-
3m @ 1.28% Cu
-
10m @ 0.55% Cu
-
Rock samples up to 45.7% Cu
Scout drilling completed in August returned:
-
10.5m @ 1.02% Cu (incl. 1.5m @ 3.99% Cu)
-
1.5m @ 1.33% Cu from 32m downhole
Mineralisation remains open along strike and at depth. Two drill holes for a total of 184m were completed to target both depth and strike extensions to the copper mineralised zone.
STAR RANGE SILVER-ANTIMONY PROJECT
OVERVIEW
The Star Range Silver-Antimony Project is located in Beaver County, Utah, one of the most mining-supportive jurisdictions in the U.S. The Project comprises 186 unpatented lode claims for 3,582 acres (14.5km²).
Star Range is strategically positioned near:
-
the historical Horn Silver mine, which produced 17 Moz silver, 25 Koz gold and 9 Mlb copper;
-
numerous copper prospects with active or historical mining; and
-
established rail, sealed roads, power infrastructure and accessible services with year-round access.
The region has an expanding role in the U.S. domestic critical minerals supply, with copper and silver now designated as critical minerals and antimony remaining globally supply constrained.
GEOLOGY & MINERALISATION
The Star Range Project is located within a historically productive mineral region in southwestern Utah, where mining activity extended into the mid-1960s and produced lead, zinc, copper, gold and silver.
Mineralisation occurs within a structurally controlled Basin and Range geological setting comprising north-striking, east-dipping carbonate and clastic sedimentary sequences from Palaeozoic to Tertiary age. These rocks are intruded by multiple granitic intrusive bodies, including outcropping porphyritic quartz monzonite, which have a spatial association with mineralisation.
Mineralisation is predominantly developed as structurally controlled replacement zones and breccia vein systems, commonly coincident with chemically reactive sedimentary contacts and historical workings.
RECONNAISSANCE ROCK SAMPLING
A total of 65 reconnaissance rock samples are currently at the laboratory with results pending. This sampling program was designed to further define and extend target zones identified during the initial sampling phase of 51 rock grab samples.
This program confirmed the presence of multiple high-grade vein-breccia systems, returning peak grades of 3,043 g/t Ag and 0.7% Sb. The initial sampling campaign has demonstrated that Star Range hosts mineralisation supported by a suite of consistently strong results across the primary prospect areas.
These results correlate strongly with historical sampling that recorded bonanza silver grades up to 8,760 g/t Ag with >1% Sb at surface. Much of the historical sampling did not report antimony, highlighting significant upside potential and an important focus for ongoing exploration.
SIGNIFICANT SAMPLING RESULTS
North Star Prospect
-
3,043 g/t Ag (97.8 oz) and 1.37 g/t Au
-
1,592 g/t Ag (51.2 oz) and 0.7% Sb
-
2,311 g/t Ag (74.3 oz) and 0.4% Sb
-
1,243 g/t Ag (40 oz) and 0.2% Sb
-
998 g/t Ag (32.1 oz), 0.2% Sb and 0.78 g/t Au
South Star Prospect
-
1,609 g/t Ag (51.7 oz) and 4.82 g/t Au
Silver Gulch Prospect
-
2,350 g/t Ag (75.6 oz) and 0.3% Sb
-
1,692 g/t Ag (54.4 oz) and 0.1% Sb
Initial prospecting has also located two new copper prospects:
-
Cu results including 4.0% and 1.5% from old workings located ~1.4km SW of North Star; and
-
Cu to 1.0% and 0.15 g/t Au from old workings located ~0.8km north of the North Star.
Early analysis of the Star Range Project geochemical data suggests mineral zonation from north to south, with exceptionally high Pb and Zn values at North Star, and Ag–Sb–Au dominant mineralisation at South Star and Silver Gulch.
Contact details:
Lyle Thorne – Chief Executive Officer
Email: [email protected]
Jane Morgan – Investor and Media Relations
Email: [email protected]
