Astral Resources NL (ASX:AAR) has returned strong high-grade gold assays from in-fill drilling at the Theia deposit, reinforcing confidence in the Stage 1 open pit development plan for its 100%-owned Mandilla Gold Project near Kalgoorlie in Western Australia.
Mandilla includes the Theia, Iris, Eos and Hestia deposits and sits in the northern Widgiemooltha greenstone belt, a region that hosts major gold operations including the Golden Mile Super Pit, St Ives and Beta Hunt. In April 2026, Astral announced a mineral resource estimate of 53.5 million tonnes at 1.0 g/t gold for 1.74 million ounces of contained gold at Mandilla.
The company has received results from the first 47 holes, covering 5,107 metres, of an ongoing reverse circulation drilling program designed to support the conversion of Stage 1 open pit resources at Theia into the higher-confidence Measured Resources category.
High-grade results support Stage 1 plan
Best results from the program include 4 metres at 16.4 g/t gold from 58 metres, including 1 metre at 61.3 g/t; 10 metres at 5.13 g/t from 37 metres, including 1 metre at 41.8 g/t; and 2 metres at 22.0 g/t from 44 metres, including 1 metre at 43.5 g/t.
Other strong assays included 6 metres at 6.82 g/t from 70 metres, including 1 metre at 30.2 g/t, along with 16 metres at 2.3 g/t from 114 metres, including 1 metre at 12.2 g/t.
Cross-section A-A’ view of the Theia Deposit showing the drill trace and assay results for the current in- fill RC drilling (please note - previous drillholes are not drawn with reported assay intervals).
The assays continue to validate the geological and mineral resource model for Theia, with broad and consistent grade intervals hosted in laterally continuous zones of quartz-sulphide veining dipping shallowly to the south-west.
“Progressively de-risking” Mandilla
Managing director Marc Ducler said the in-fill drilling was delivering “exactly what we are looking for” by confirming continuity of high-grade mineralisation within the Stage 1 pit and de-risking the early years of Mandilla’s proposed development.
“Our ongoing in-fill drilling continues to deliver exactly what we are looking for – strong continuity of high-grade mineralisation within the Stage 1 pit while progressively de-risking the early years of the Mandilla development,” Ducler said.
Ducler said the three-phase program was progressively tightening drill spacing to 12.5 metres by 12.5 metres to support the declaration of Measured Resources across the Stage 1 mining inventory.
Theia remains central to Mandilla
Theia is the cornerstone deposit at Mandilla, hosting a mineral resource estimate of 41.0 million tonnes at 1.1 g/t gold for 1.4 million ounces of contained gold.
Under the Mandilla pre-feasibility study, Theia contributes 1.1 million ounces, or about 75% of the total 1.48-million-ounce production case, making it central to the project’s economics.
The Stage 1 open pit covers 4.2 million tonnes at 1.1 g/t gold for 146,000 ounces over the first 21 months of the project, with a strip ratio of 4:1.
Drilling to continue through 2026
Astral has completed 132 holes for 13,300 metres of the broader 431-hole, 44,400-metre Stage 1 in-fill program, which is expected to continue through the remainder of 2026.
Two rigs are currently operating at Mandilla, with diamond drilling also underway. Nine holes of an expanded 11-hole, 6,000-metre program have been completed, while additional holes are being planned to test Theia mineralisation up and down-dip.