Key Highlights

  • Diablo Resources Limited (ASX:DBO) reported tungsten trioxide grades of up to 0.37% from surface sampling at the Cupric prospect on 26 October 2026, with six samples returning grades above 0.1% WO₃.
  • The exploration programme also identified copper, gold and silver mineralisation, including a channel sample of 2.6 metres at 1.56% copper and a selective grab sample containing 398 grams per tonne silver.
  • Diablo Resources Limited (ASX:DBO) reported AUD 1.25 million in cash at 30 June 2026 and is progressing its maiden North Star drilling programme while assessing potential drilling targets at Horn Silver for early 2027.

Diablo Resources Limited (ASX:DBO) is an Australian-listed mineral exploration company with projects in the United States, including its Star Range and Horn Silver projects in Utah. The company is investigating silver, antimony, copper and gold mineralisation across the historic Frisco Mining District. On 26 October 2026, Diablo Resources Limited (ASX:DBO) announced tungsten results from reconnaissance sampling at the Cupric prospect, identifying another mineral of interest within its Horn Silver exploration portfolio. The results expand the range of commodities under investigation, although additional geological work and drilling will be required to establish the extent and significance of the mineralisation.

What Do the Latest Cupric Tungsten Results Reveal?

Diablo Resources Limited (ASX:DBO) completed first-pass reconnaissance sampling at the Cupric prospect, located within its Horn Silver Project in Beaver County, Utah. The programme involved collecting surface rock samples from historical workings, outcrops and mineralised material to assess the presence of tungsten and associated metals.

The company reported six samples containing more than 0.1% tungsten trioxide (WO₃), with the highest grade reaching 0.37% WO₃. Other reported samples returned 0.22% WO₃ and 0.17% WO₃, with the latter also containing 2.82 grams per tonne gold. These results indicate that tungsten occurs alongside other mineralisation within the sampled geological system.

Channel sampling identified a 2.6-metre interval grading 1.56% copper, including 1.3 metres at 0.12% WO₃. The company also reported a 4.5-metre interval containing 1.26% copper and 0.46 grams per tonne gold. However, these results represent selected sampling locations rather than average grades across the prospect.

Why Is Tungsten Significant for Diablo Resources' (ASX:DBO) Exploration Strategy?

The identification of tungsten introduces an additional critical mineral exploration opportunity within Diablo Resources Limited's (ASX:DBO) existing Utah landholding. Tungsten is used in industrial equipment, aerospace components, cutting tools and other applications requiring materials with high hardness and heat resistance. Its industrial characteristics make it relevant to supply chains involving specialised manufacturing and defence-related technologies.

The Cupric results suggest that tungsten may occur within a broader polymetallic mineralised system containing copper, gold and silver. This association could influence future exploration planning by encouraging the company to investigate several commodities within the same geological structures.

However, the discovery of tungsten in surface samples does not establish a commercially viable deposit. Further mapping, sampling and drilling will be required to determine whether mineralisation continues beneath the surface and whether sufficient volumes exist to support a Mineral Resource estimate.

How Do Copper, Gold and Silver Results Support the Cupric Assessment?

Alongside tungsten, Diablo Resources Limited (ASX:DBO) reported copper, gold and silver results from the Cupric prospect. Channel sampling identified copper-bearing intervals, including 4.5 metres at 1.26% copper and 0.46 grams per tonne gold, while another interval returned 3.0 metres at 1.00% copper and 0.11 grams per tonne gold.

A selective grab sample collected from historical mine dump material returned 12.5% copper, 3.29 grams per tonne gold and 398 grams per tonne silver. These concentrations provide evidence that multiple metals occur within the local mineralised system, although samples from historical dumps may not accurately represent the grade or continuity of material remaining underground.

The association between tungsten and other metals may help refine geological interpretations of Cupric. However, individual high-grade samples cannot be used to estimate the average grade, tonnage or economic value of the broader prospect without systematic exploration.

What Does Historical Mining Activity Reveal About Cupric?

The Cupric prospect contains historical underground workings associated with mineral exploration and development activities undertaken during the 1940s. These workings include two adits that were developed to investigate mineralised structures during a period of heightened industrial demand for tungsten.

Diablo Resources Limited (ASX:DBO) has reviewed available historical records alongside recent surface sampling results to assess the geological significance of these workings. Historical mining activity provides evidence that mineralisation was previously identified, but it does not independently demonstrate the presence of a deposit meeting modern resource reporting requirements.

The company intends to undertake additional underground geological mapping, surveying and sampling to evaluate the structures associated with the old workings. Petrographic studies may also help identify the minerals hosting tungsten and clarify their relationship with copper, gold and silver mineralisation.

These activities are intended to provide information for ranking Cupric against other targets within the Horn Silver Project.

How Does Cupric Fit Within the Horn Silver Project?

Diablo Resources Limited (ASX:DBO) holds an 80% interest in the Horn Silver Project through its subsidiary, Antler Resources LLC. The project covers approximately 13 square kilometres within Utah's historic Frisco Mining District and contains multiple exploration targets associated with silver and other metals.

The company's existing exploration activities have focused on identifying mineralised structures that could extend beyond historical workings. The addition of tungsten at Cupric broadens the commodities being assessed within the project area, although it does not change the early-stage status of the asset.

The company is considering an initial drilling programme at Horn Silver during the first quarter of calendar 2027. The selection of drilling targets will depend on geological mapping, surface sampling and technical assessments across the project's prospects.

Cupric could become part of this exploration programme if further investigations establish suitable targets, but no Mineral Resource or Ore Reserve has been declared at Horn Silver.

What Progress Has Been Made at the North Star Prospect?

Diablo Resources Limited (ASX:DBO) commenced its maiden diamond drilling programme at the North Star prospect on 2 September 2026. North Star is located within the company's wholly owned Star Range Project, which covers approximately 21 square kilometres in the Frisco Mining District.

The initial programme comprises approximately 1,000 metres across five diamond drill holes, targeting silver, antimony, copper and gold mineralisation beneath areas previously investigated through surface sampling and geophysical surveys. Drilling targets were selected using geological mapping and induced-polarisation anomalies interpreted to be associated with mineralised structures.

Earlier selective rock sampling at North Star returned silver grades of up to 3,043 grams per tonne, alongside gold and antimony mineralisation. However, these results represent individual surface samples and do not establish the average grade of the underlying system.

Assay results from the maiden drilling programme had not been reported as of 27 October 2026, making the interpretation of subsurface mineralisation an important forthcoming milestone.

What Do Diablo Resources Limited's (ASX:DBO) FY26 Financial Results Show?

Diablo Resources Limited (ASX:DBO) reported a net loss after tax of AUD 1.17 million for FY26, compared with AUD 762,528 in FY25. The wider loss reflected increased corporate expenditure and the company's continuing exploration activities. As an early-stage mineral explorer, Diablo has not established commercial mining revenue from its United States projects.

Cash and cash equivalents increased to approximately AUD 1.25 million at 30 June 2026 from AUD 180,331 at 30 June 2025, supported by financing activities undertaken during the year. Net cash used in operating activities was approximately AUD 875,823, while exploration and evaluation cash payments totalled approximately AUD 1.44 million.

Total assets increased to approximately AUD 3.41 million at the end of FY26, compared with AUD 764,638 a year earlier. The company's financial statements also identified material uncertainty regarding its ability to continue as a going concern if sufficient additional capital cannot be obtained to fund planned expenditure.

The June 2026 cash balance therefore provides a historical funding reference rather than confirmation that all subsequent drilling commitments are fully financed.

What Are the Main Exploration and Financial Risks?

Diablo Resources Limited (ASX:DBO) faces geological uncertainty because the Cupric tungsten results were obtained from selective surface and channel sampling rather than a systematic drilling programme. Although several samples contained notable tungsten, copper, gold and silver grades, the continuity and economic significance of mineralisation have not been established.

The company also faces funding requirements associated with its maiden North Star drilling campaign and planned exploration at Horn Silver. Its FY26 accounts identified material uncertainty concerning future financing, meaning additional capital may be required to support exploration and corporate expenditure.

Regulatory approvals, land access and operating conditions in the United States could influence the timing of future drilling. Commodity price movements may also affect the economics of any future discoveries, while the absence of Mineral Resources across the portfolio limits the ability to assess potential development outcomes.

What Are the Next Milestones for Diablo Resources Limited (ASX:DBO)?

The immediate priority for Diablo Resources Limited (ASX:DBO) is receiving and interpreting assay results from its maiden North Star diamond drilling programme. These results will provide the first modern subsurface testing information for selected silver-antimony targets and may determine whether additional drilling is warranted.

At Cupric, the company intends to undertake underground sampling, geological mapping and surveying of historical adits, together with petrographic investigations to clarify the distribution and characteristics of tungsten-bearing mineralisation. The findings will help rank Cupric alongside other prospects within the Horn Silver Project.

Diablo is also preparing for potential maiden drilling at Horn Silver during 1QCY27, subject to target definition, funding and regulatory requirements. Future quarterly cash flow disclosures will provide updated information on available funding and exploration expenditure as the company progresses its Utah programme.