Astral Resources NL (ASX:AAR) has intersected broad gold mineralisation well below the current resource envelope at the 1.4-million-ounce Theia deposit, part of its 100%-owned Mandilla Gold Project near Kalgoorlie in Western Australia.
The first hole of a 9-hole, 5,500-metre diamond drilling program returned 358.23 metres at 1.03 g/t gold from 256.17 metres in AMRCD263, with mineralisation extending to 614.4 metres downhole.
The result extends mineralisation 210 vertical metres below the current Theia Mineral Resource Estimate.
Higher-grade zones included 15.70 metres at 3.40 g/t gold from 320.44 metres, including 0.43 metres at 121.6 g/t, and 127.27 metres at 1.20 g/t from 352 metres, including several narrow high-grade intervals of up to 72.2 g/t gold.
A deeper zone returned 81.46 metres at 1.35 g/t gold from 515.04 metres, including 1.13 metres at 42.7 g/t.
Cross-section view of the Theia Deposit showing the MRE block model3, gram x metre interval (AMRCD263), logged visible gold and the quartz vein percentage value.
The intersection occurred largely outside the current Theia resource and confirmed the mineralised system continued at depth.
The company noted a strong correlation between quartz veining, trace sulphides, visible gold and economic gold mineralisation, consistent with previous observations at Theia.
Managing director Marc Ducler said the first Theia Deeps hole provided “strong evidence” that the gold system extended beyond the current 1.4-million-ounce resource.
“The first hole from our Theia Deeps diamond drill program delivered highly encouraging results, providing strong evidence that the Theia gold system appears to extend well beyond the limits of the current 1.4Moz Mineral Resource.
“Importantly, within a spectacular 358-metre total intersection, broad zones of mineralisation such as 127.3m at 1.20g/t Au from 352m and 81.5m at 1.35g/t Au from 518m occur almost entirely outside the existing resource envelope and demonstrate significant potential to continue growing the Theia deposit at depth.
“Geological logging of this hole showed quartz veining, trace sulphides and visible gold — all of which have previously been strong indicators of economic gold mineralisation at Theia, which has been confirmed by these latest gold assays, returning strong widths and grades.
“We are also very encouraged by geological logging of the recently completed third diamond hole which has been extended beyond its planned depth of 500 metres to a final down-hole depth of 605 metres.
“Processing of the diamond core is well advanced, with the second drill-hole (AMRCD259) processed and pending assay returns. The third drill-hole (AMRCD264) has also been processed with samples being dispatched to the lab this week.”
Potential resource growth
The results are significant because Theia is the cornerstone deposit within Mandilla, which hosts a total resource of 53.5 million tonnes at 1.0 g/t gold for 1.74 million ounces.
Mandilla forms part of Astral’s broader 2.07-million-ounce group resource and was included in a 2025 pre-feasibility study outlining a standalone 2.75-million-tonne-per-annum operation producing 95,000 ounces per year for the first 12 years.
What’s next
Drilling is continuing, with three holes completed in the current diamond program and the fourth underway.
The second hole, AMRCD259, has been processed and is awaiting assays, while the third hole, AMRCD264, has also been processed, with samples being dispatched to the laboratory.
Astral is also continuing RC infill drilling across the Stage 1 Theia open pit to support a potential increase in Measured Resources ahead of planned mining.