Astral Resources has joined a rare class of WA gold developers, topping 2Moz of contained gold as a project update delivers a 22% increase and opens an underground mining option at the key Theia deposit (reports Stockhead).

Astral Resources (ASX:AAR) group MRE uplift to 62Mt at 1.1g/t for 2.07Moz firmly cements it as a significant emerging gold producer thanks to its growing Mandilla gold project, located 70km south of Kalgoorlie in WA.

“This update to the Mandilla mineral resource estimate is an important precursor to the detailed mine design work that is now underway to support the Mandilla DFS,” AAR managing director Marc Ducler said.

“Pleasingly, the MRE has also delivered a significant 22% increase (at Mandilla) in contained gold from 1.43Moz to 1.74Moz.”

Tabled at a gold price of just A$4500/oz, the Mandilla resource is also priced right to ride out volatility, with a definitive feasibility study in the works.

And the exploration success is real.

If reported on a like-for-like basis with the April 2025 MRE, which used a A$3500 gold price and 0.39g/t lower cut-off, Astral said the updated MRE at the flagship Theia deposit still increased by 15%.

Gold is holding around US$4820/oz or A$6700/oz and some analysts see it reaching US$6000/oz amid stock market gyrations and geopolitical tension.

Theia, representing approximately 80% of the Mandilla MRE, remains the flagship deposit, and a key driver for this resource update was to understand the MRE’s response to the 12.5m x 12.5m in-fill drilling recently completed within the Stage 1 Theia open pit.

“Importantly, the outcome of the in-fill program was a very strong validation of the geological interpretation and estimation methodology,” Ducler said.

“The fact that both grade and ounces have increased by 5.2% and 4.2% respectively demonstrates a strong confidence in our estimation methodology.”

In-fill drilling is ongoing at Theia, with a 23,000m program underway to continue progressing the remainder of Stage 1 to a 12.5m x 12.5m drill spacing.

This will ensure the first 12 to 18 months of mine production is derived from the measured resource category.

“Notwithstanding the recent volatility in the gold price, the price is 100% higher than the design assumptions used in the June 2025 PFS,” Ducler said.

“In this environment, and given our confidence that the Theia deposit remains open at depth, we are now evaluating an underground mining option for Theia.”

A diamond drill rig is currently undertaking a 6-hole (3000m) program targeting up to 175m of vertical depth extension across several sections below the central Theia deposit.

“This program, aiming to scope the potential scale of the Theia mineral system, has the potential to define substantial future growth potential if successful,” Ducler said.

The JORC-compliant Mandilla MRE was prepared by independent consultant Cube Consulting and incorporated the Theia, Iris, Hestia and Eos deposits for a total of
54Mt at 1.0g/t Au for 1.74Moz of contained gold.

Including the Feysville MRE of 5Mt at 1.2g/t Au for 196,000oz of contained gold and the Spargoville MRE of 3Mt at 1.4g/t Au for 139,000oz of contained gold, the group MRE is now estimated at 62Mt at 1.1g/t Au for 2.07Moz of contained gold. 

A year ago, the MRE for the Iris deposit was estimated at 4.3Mt at 0.8g/t for 108,000oz of contained gold.

This April 2026 update has increased the MRE by 47% to 6.5Mt at 0.8g/t for 159,000oz of contained gold.

Some 19 holes for 2971m of in-fill were completed in the central portion of Iris and the deposit also benefitted from 14 RC holes (1461m) drilled in the gap between Theia and Iris, which extended the Iris deposit significantly to the north.

The Theia and Iris pit shells are now overlapping and with a further 27 RC holes (2814m) planned to be drilled in the Theia-Iris gap the company said there was potential for the Iris deposit to continue expanding to the north and the two pits fully merging.

Astral continues to maintain a dual focus on MRE growth and greenfields exploration.

The Mandilla DFS continues to advance, with the engineering work streams progressing well and the mine design work now underway, incorporating this latest MRE update, Astral said.

Testing for depth extensions at Theia is the current major activity.

Extensional and in-fill drilling at Feysville’s Kamperman deposit and exploration targeting across the prospective Spargoville tenement package will resume later this quarter.