Yandal Resources Ltd (ASX:YRL) has expanded the known strike of the Arrakis mineralised structure at its Caladan target within the Ironstone Well-Barwidgee Gold Project in Western Australia, with new assay results extending the zone by a further 400 metres to more than 1.2 kilometres. The structure remains open to both the northwest and southeast.
The second batch of assays from the company’s 132-hole, 13,458-metre air-core (AC) drilling program delivered strong intercepts, including:
- 11 metres at 1.4 grams per tonne (g/t) gold from 71 metres, including 6 metres at 2.3 g/t from 72 metres in hole 25IWBAC044
- 1 metre at 1.0 g/t gold from 87 metres to end-of-hole in the same hole
These results build on previously reported mineralisation such as 11 metres at 2.1 g/t from 90 metres and 12 metres at 1.1 g/t from 45 metres, highlighting the discovery potential at Caladan.
With 86 holes still pending assay, Yandal plans follow-up reverse circulation and air-core drilling in August, alongside heritage surveys to enable closer-spaced drilling along the growing mineralised corridor.
“Results continue to demonstrate the discovery potential of the Caladan target area. Again, we have seen mineralisation occurring in a very consistent position relative to the 3-kilometre Arrakis regolith anomaly. Results demonstrate the potential for the now more than 1.2-kilometre-long mineralised structure that remains open along strike to the northwest and southeast to be further extended,” Yandal Resources managing director Chris Oorschot said.
“Drilling has been completed on lines a further 800 metres to the southeast and northwest of the current results. With samples from a further 86 holes at the lab and anticipated results due over the coming weeks, there is plenty to look forward to.
"With the Caladan air-core program complete, follow-up RC and further air-core drilling have been scheduled for August. In addition to this, several heritage surveys have been booked to clear closer-spaced drill lines across the interpreted mineralised structure.
"We are razor-focused on continuing to explore across and progressing discoveries at both the Caladan and New England Granite target areas, and the Company remains well-funded to do so.”
Caladan target area: Fold structure shows early signs of mineralisation
The Caladan target area is emerging as a priority exploration focus for the company, underpinned by the discovery of a large-scale, northwest-plunging fold truncated by the Idaho Shear. This shear is interpreted as a second-order fault linking the Ockerburry Shear Zone to the east and Barwidgee Shear Zone to the west. Initial exploration has already revealed a 3 kilometre-long regolith anomaly — CAL-01 — now defined as the Arrakis Prospect.
Air-core and reverse circulation (RC) drilling campaigns completed in 2024 and early 2025 indicate strong mineralisation potential, with assays identifying gold depletion zones in the regolith and primary gold hosted in deformed mafic units. Follow-up RC drilling has also intercepted gold along the flanks of a sub-vertical shear zone, 20 to 30 metres wide, with multiple structures yet to be tested.
First drilled systematically in 1995 using shallow vertical rotary air blast (RAB) holes, the Caladan Fold was only sparsely tested. Drilling was spaced on a 400-by-400-metre grid and targeted in-situ saprolite clays beneath shallow cover. These early efforts uncovered several low-level saprolite anomalies, with CAL-01 emerging as the largest.
The broader fold structure spans approximately 3 kilometres in width and more than 8 kilometres in length, lying beneath 8 metres of transported cover on average. The structural setting bears similarities to the Kalgoorlie district, where gold mineralisation is closely associated with folding and major fault zones such as the Boulder-Lefroy Fault.
2024–2025 exploration highlights
A single line of air-core drilling conducted in 2024 confirmed key geological features:
- Gold depletion in the upper regolith;
- CAL-01’s likely association with deformed and altered mafic rocks;
- Gravity highs aligning with fractionated dolerites and altered intermediate volcaniclastics.
Subsequent RC drilling in early 2025 supported the presence of gold-bearing structures on the margins of a vertical shear zone hosted in basalt and dolerite. The presence of multiple, untested structures in fresh rock highlights broader mineralisation potential.
Upcoming exploration and priority ranking
The Caladan Fold remains significantly under-explored. Based on geological indicators and early drilling success, the company has ranked Caladan as a top-tier target within its exploration portfolio.
Key activities planned for the second half of 2025 include:
- Assays from 86 additional holes at Caladan expected within 4–6 weeks;
- A new air-core program underway across the New England Granite target;
- Further RC and air-core drilling across the Arrakis Prospect, scheduled for August;
- Heritage surveys for closer-spaced drill clearance at Caladan and Arrakis, scheduled for late August and September.