Astral Resources reports strong assay results from infill drilling at Theia, underpinning resource upgrades and de-risking early Mandilla mine development near Kalgoorlie.
- High-grade gold assays reinforce Theia Stage 1 resource model
- Ongoing infill drilling aims to upgrade resources to Measured category
- Mandilla hosts 2.07Moz gold resource with 1.08Moz Ore Reserves
- Program expected to continue through 2026 supporting feasibility
- Metallurgical tests confirm excellent gold recoveries and processing
Robust Gold Grades Support Stage 1 Resource Upgrade
Astral Resources (ASX:AAR) has delivered assay results from the first 47 holes of its ongoing infill reverse circulation drilling program at the Theia deposit, part of the Mandilla Gold Project near Kalgoorlie. The standout intercepts include multiple high-grade intervals such as 4 metres at 16.4 g/t gold from 58 metres, including a blistering 1 metre at 61.3 g/t, and several other shoots exceeding 20 g/t over short widths. These results validate the geological model underpinning the Stage 1 open pit resource and provide confidence to upgrade this inventory to the Measured Resources category.
Theia is the cornerstone deposit at Mandilla, contributing approximately 75% of the 1.48 million ounces targeted in the project's Pre-Feasibility Study (PFS). The current infill program aims to tighten drill spacing to 12.5 by 12.5 metres, a density sufficient for Measured Resource declaration, which is critical for de-risking the early mine stages.
Mandilla’s Resource and Reserve Base Remains Solid
The Mandilla Gold Project hosts a consolidated Mineral Resource Estimate (MRE) of 61.6 million tonnes at 1.0 g/t gold for 2.07 million ounces, including measured, indicated, and inferred categories. Ore Reserves stand at 36.6 million tonnes grading 0.9 g/t for 1.08 million ounces, based on a gold price of AUD 3,000 per ounce. These figures reflect the combined inventory across Mandilla and the nearby Feysville and Spargoville projects.
Metallurgical test work on Mandilla’s deposits, including Theia, Iris, Eos, and Hestia, continues to demonstrate excellent gravity recoverable gold, rapid leach kinetics, and high overall recoveries with low reagent consumption. This metallurgical profile supports the economic viability outlined in the PFS, which assumes a base case gold price of AUD 4,250 per ounce and delivers an NPV8 of AUD 1.4 billion.
Drilling Program Progress and Development Implications
To date, Astral has completed 132 holes for 13,300 metres of the current 431-hole (44,400 metres) infill RC program at Theia Stage 1, with the drilling expected to continue throughout 2026. The company is also advancing a deep diamond drilling program to test the mineral system's extent below the open pit. These efforts aim to refine resource classifications and support the progressing Definitive Feasibility Study (DFS).
Managing Director Marc Ducler highlighted that the drilling is delivering consistent high-grade zones within broad mineralised intervals, specifically within quartz-sulphide veining and altered granite host rocks. This continuity is essential for mine planning and supports the early years of production, which are pivotal for project economics.
While sterilisation and additional drilling at other project areas such as Kamperman (Feysville) and Spargoville remain on hold pending heritage clearances, the focus on Theia underscores its strategic importance to Astral’s development roadmap.
Geological Context and Historical Exploration
The Mandilla Gold Project lies within the prolific Widgiemooltha greenstone belt, an area known for world-class gold deposits like the Golden Mile Super Pit and Beta Hunt. Theia mineralisation is structurally controlled along major thrust faults and associated with quartz veins exhibiting visible gold. The deposit extends over a strike length of more than 1.6 kilometres with mineralised zones dipping shallowly southwest.
Historical drilling and exploration since the late 1980s have progressively delineated gold mineralisation, with recent programs enhancing confidence in resource continuity and grade distribution. The current drilling results reinforce these findings, supporting the geological interpretations and resource models.
Next Steps for Astral Resources at Mandilla
Astral’s ongoing drilling and resource refinement at Theia will be closely watched as the company advances its DFS and prepares for potential mine construction. The ability to convert significant portions of the resource to the Measured category reduces development risk and underpins more detailed economic studies. The continuation of high-grade intercepts through the drilling program bodes well for maintaining robust production profiles in the initial mine years.
With metallurgical work confirming favourable processing characteristics and a solid reserve base, the Mandilla project is shaping as a key asset for Astral Resources. However, the ultimate impact on production timelines and capital requirements will depend on forthcoming DFS results and the pace of heritage clearances for broader project drilling.
Bottom Line?
Mandilla’s Theia deposit continues to deliver high-grade gold continuity, reinforcing resource upgrades and supporting Astral’s path toward production, but ongoing drilling and feasibility work remain critical to confirm the project’s economic potential.
Questions in the middle?
- Will the ongoing infill drilling convert a substantial portion of Theia’s resource to Measured status as planned?
- How will the Definitive Feasibility Study incorporate these latest high-grade assay results into project economics?
- What impact will heritage clearance delays have on drilling programs at Feysville and Spargoville, and the broader development timeline?