Iltani Resources Confirms Sulphide Mineralisation Across 1,230 Metres at Union Jack

Iltani Resources Confirms Sulphide Mineralisation Across 1,230 Metres at Union Jack Prospect

Iltani Resources (ASX: ILT) has reported that all three reverse circulation drill holes completed at the Union Jack Prospect in Northern Queensland intercepted lead, zinc and copper sulphide mineralisation. The Iltani Resources Union Jack sulphide mineralisation drilling results span a distance of 1,230 metres across a prospect that had never previously been drill tested, pointing to what the company has described as potential for a large-scale mineralising system.

Union Jack sits within the Featherbed Volcanics, approximately 11km northwest of Iltani's flagship Orient Silver-Indium Project, and forms part of the broader Herberton Project in Northern Queensland. Samples from the drilling program have been submitted to Intertek's Townsville laboratory, with assay results expected within one to two months.

What Was Found: Three Holes, Three Hits

According to the announcement, Iltani completed 666 metres of RC drilling across three holes, designated UJRC0001, UJRC0002 and UJRC0003. The program was designed to test both historical workings at the Union Jack site and newly identified geophysical anomalies generated by the company's 2025 airborne VTEM survey. Every hole returned visual sulphide mineralisation, based on geological logging of drill chips.

The table below summarises the key visual intercepts reported from each hole. All widths are downhole measurements, and true widths have not yet been established.

The standout result is UJRC0002, which intersected 9 metres of visual sulphide mineralisation at up to 35% total sulphides at a depth of 165 to 174 metres, in a location the company reports aligns closely with where its geophysical modelling had predicted the VTEM anomaly plate to sit.

Iltani has described this alignment between the geophysical model and the physical drill result as confirming the ability of the survey to locate previously unknown sulphide mineralisation across the wider project area.

UJRC0003, drilled 1,230 metres from UJRC0002, returned 13 metres of visual sulphide mineralisation from just 6 metres depth, with abundances reaching up to 25 to 30% in individual one-metre intervals according to the geological logs. The company notes that a second VTEM plate of opposite dip and lesser magnitude was also interpreted at this location, which may offer a better model for future drill targeting.

It should be noted that visual estimates of sulphide abundance are not a substitute for laboratory assay results, and actual metal grades across these intercepts remain to be confirmed.

"We have successfully completed the Union Jack drilling, as part of the regional Herberton Project exploration program. The drilling was a great success, intercepting sulphide mineralisation in all holes, with assays pending, expected in the next 2 months. It was particularly pleasing to see that UJRC0002 intersected a strong zone of sulphide mineralisation exactly where the geophysical modelling of the VTEM plate predicted, which confirms the ability of the airborne geophysical VTEM survey to locate hitherto unknown sulphide mineralisation. Once we have the assay results back, we will plan our next steps, we will be back at Union Jack sooner rather than later." — Managing Director Donald Garner

Understanding VTEM Surveys: The Technology Behind the Discovery

One of the more technically significant aspects of this announcement relates to the apparent validation of Iltani's airborne VTEM survey as an exploration tool.

What Is VTEM?

VTEM stands for Versatile Time Domain Electromagnetic. It is an airborne geophysical survey method in which a helicopter tows a large electromagnetic transmitter loop over the ground. The system sends pulses of electromagnetic energy into the earth, which generate secondary electrical responses in conductive materials, including sulphide minerals. These responses are recorded and used to model where conductive bodies may exist beneath the surface, without the need for physical drilling.

Why Does It Matter for Investors?

VTEM surveys allow exploration companies to identify drill targets in areas with no surface expression of mineralisation, meaning targets that traditional surface sampling would not detect. The reported alignment between the UJRC0002 intercept and the modelled VTEM plate VT16_A suggests the remaining untested VTEM anomalies across the Herberton Project may also warrant drill testing, according to the company.

Furthermore, Iltani's 2025 Herberton Project VTEM Survey identified 16 high-priority anomalies across the project area. Following the Union Jack result, the company has stated it will reassess these anomalies to prioritise further drill testing.

The VTEM survey was completed with the support of $230,375 received through Round 9 of the Queensland Government's Collaborative Exploration Initiative (CEI) Scheme, which co-funded the geophysical work that generated the drill targets.

Glossary of Key Terms

• RC Drilling (Reverse Circulation): A drilling method where rock chips are returned to the surface through the drill rods, producing samples for geological logging and assay.
• Sulphide mineralisation: Metal-bearing minerals in which metals are chemically bound to sulphur, a common host for lead, zinc, copper and silver in base metal systems.
• Pyrite: Iron sulphide, often associated with base and precious metal deposits as an indicator mineral.
• Sphalerite: Zinc sulphide, the primary ore mineral for zinc and frequently the host mineral for indium.
• Galena: Lead sulphide, the primary ore mineral for lead and often a carrier of silver.
• Chalcopyrite: Copper iron sulphide, the most common ore mineral for copper.
• DHEM (Downhole Electromagnetic Survey): A higher-resolution electromagnetic survey conducted from within a drill hole, providing more precise geometry of nearby conductive bodies than airborne surveys.
• Propylitic alteration: A type of hydrothermal rock alteration involving minerals such as chlorite and epidote, commonly associated with epithermal and porphyry-style mineralisation.

The Strategic Significance: Satellite Deposits for the Orient Plant

Union Jack is being explored as part of a broader regional strategy rather than in isolation. Iltani's flagship Orient Silver-Indium Project holds a JORC Mineral Resource of 62.5 Mt at 81.5 g/t silver equivalent, comprising silver, indium, lead and zinc, as detailed in the table below.

A stated objective of Iltani's regional exploration program is to identify satellite deposits within trucking distance of a potential Orient processing plant, which the company has indicated is likely to be located on tenement EPM 27223. Union Jack sits approximately 11km from Orient and, should assays confirm economic grades, could be positioned as a complementary resource under this model.

This hub-and-spoke approach — where a portfolio of satellite deposits feeds ore into a central processing facility — is an established model within the mining industry that can help reduce per-tonne processing costs relative to standalone operations.

What Happens Next: A Pipeline of Catalysts

Iltani has outlined several near-term activities following completion of drilling at Union Jack.

1. Assay results (1 to 2 months): Samples from all three holes have been submitted to Intertek Townsville. Results will determine actual metal grades across the visually identified sulphide intercepts.

2. Downhole EM (DHEM) survey, later in 2026: Polypipe has been installed in UJRC0002 and UJRC0003 ahead of a planned DHEM survey once a suitable geophysical crew becomes available. This survey is expected to provide higher resolution than the airborne VTEM survey in defining the geometry and depth extent of sulphide bodies.

3. Detailed surface mapping and sampling: The company plans additional geological mapping and surface sampling at Union Jack to assess any surface indicators of mineralisation associated with the historical workings and the shallow UJRC0003 intercept.

4. VTEM anomaly reassessment: Following the UJRC0002 result, Iltani intends to reassess the remaining VTEM anomalies at Union Jack and across the wider Herberton Project area to prioritise future drill targets.

5. Further drilling at Union Jack in 2026: The company has indicated its intention to return to Union Jack for additional drilling once assay results and DHEM data are available.

Why This Announcement Matters for the Investment Case

First-Time Drilling Confirms Mineralisation in a New Area

Union Jack had never been drill tested prior to this program. All three holes returning sulphide intercepts in a previously undrilled area expands the known mineralised footprint of the Herberton Project. A separation of 1,230 metres between mineralised intercepts is, according to the company, an indicator consistent with a larger mineralising system, though this remains to be confirmed by further work.

Geophysical Validation May Support a Broader Target Pipeline

The reported alignment between the UJRC0002 sulphide intersection and the modelled VTEM plate VT16_A extends beyond a single result, potentially supporting the case for VTEM as a reliable targeting tool across the Herberton Project. Iltani has previously identified 16 high-priority anomalies from this survey, which the company states will now be reassessed with reference to this result.

Strategic Fit With the Orient Processing Hub Concept

Should assays confirm economic grades at Union Jack, its proximity to Orient positions the prospect as a potential contributor of ore feed to a future processing facility. Additional satellite deposits identified under this model could add value to the Orient development concept without requiring proportional additional investment in processing infrastructure, according to the company's stated strategy.

Indium Exposure Remains a Differentiator

The Orient resource contains 725 tonnes of contained indium, positioning it among the more substantial indium-bearing deposits in development. Indium is classified as a critical mineral, with industrial demand linked to touch screen manufacturing through indium tin oxide and, increasingly, to indium phosphide laser chips used in high-speed optical transceivers for data centre infrastructure. Union Jack assay results, including indium content, remain pending.

Educational Context: Why Exploration Success Rates Matter

For investors assessing early-stage exploration companies, the proportion of drill holes returning positive results — sometimes referred to as a hit rate — is a useful indicator of program quality, though it should always be considered alongside assay confirmation rather than visual observations alone.

A 100% visual hit rate across three holes targeting both historical workings and untested geophysical anomalies suggests the targeting methodology employed by Iltani has some predictive value. However, visual sulphide abundance does not equate to economic grade. Laboratory assay results, expected within one to two months according to the company, will determine whether the mineralisation identified carries sufficient silver, indium, lead, copper or zinc content to be considered economically significant.

Why Investors Should Keep Watching Iltani Resources

Iltani is executing a defined regional exploration strategy across the Herberton Project. The Union Jack program was designed to test both historical workings and geophysical targets, partly supported through CEI Scheme funding, and returned visual sulphide mineralisation across all three holes drilled.

The coming months represent a potential inflection point for the company. Assay results will either confirm or qualify the visual sulphide intercepts reported to date. Historical surface sampling at Union Jack previously returned up to 39.5 g/t silver, 2.3% copper and 25 g/t indium, according to the company's 2023 disclosures, providing a benchmark against which new assay results may be compared.

With a DHEM survey planned to provide higher-resolution targeting data, a number of untested VTEM anomalies across the Herberton Project, and assay results due within weeks, several catalysts are consequently converging around this exploration program in the near term.

"Iltani Resources has reported first-ever drilling at the Union Jack Prospect returning sulphide mineralisation across a 1,230-metre zone, complementing its 62.5 Mt silver-indium resource at the nearby Orient project. With assay results pending, a DHEM survey planned and 16 VTEM anomalies awaiting reassessment, the program presents a series of near-term milestones for investors to monitor."

Want to Learn More About Iltani Resources and Its Herberton Project?

With sulphide mineralisation confirmed across 1,230 metres at the never-before-drilled Union Jack Prospect, a 62.5 Mt silver-indium resource at Orient, and assay results expected within weeks, Iltani Resources (ASX: ILT) is approaching a series of near-term catalysts that investors will want to follow closely. To explore the company's projects, strategy and latest announcements in full, visit the official Iltani Resources website at iltaniresources.com.au.