Vault Minerals has revealed its King of the Hills (KOTH) operation in Western Australia has seen an increased open pit ore reserve, which will underpin an 18-year operating life.
Known as Vault’s flagship project, KOTH is located approximately 25km north of the Leonora region. Vault’s Leonora operations comprise the KOTH open pit and underground mines, the Darlot satellite underground mine, and the KOTH processing facility.
Vault is currently expanding KOTH to deliver six million tonnes per annum (Mtpa) in throughput rates from the middle of the fourth quarter in the 2025–26 financial year (Q4 FY26). This is then expected to grow to 7.5mtpa from late Q2 FY27.
As part of this expansion, Vault has unveiled an updated ore reserve for KOTH’s open pit.
The KOTH open pit has increased its ore reserves by 33 per cent, prior to mine depletion of 97,065 ounces (oz). The ore reserve now stands at 110 million tonnes (Mt) at 0.61g/t for 2.2 million ounces. The 572,000oz jump was based on a 0.23g/t cutoff grade.
“The increase in volume of the KOTH open pit ore reserve is primarily driven by the extension of the northern limits from Stage 4 to Stage 5,” Vault said.
“The distribution of ounces between the stages provides valuable optionality with the higher strip Stage 5 scheduled to commence waste stripping in FY32, thereby providing scheduling flexibility to adjust the operating strategy in response to any long-term gold price volatility.”
The boost in KOTH ore reserves will underpin the operation’s Stage 2 plant upgrade.
“The Stage 2 plant upgrade will now dovetail with the Stage 1 upgrade … Stage 2 capital is expected to be approximately $92 million, inclusive of owner’s costs, for an aggregate investment of $172 million, delivering a 50 per cent increase in plant throughput, increased gold recovery, and lower unit costs,” Vault said.
“The Stage 1 project capital estimate remains at $80 million, and commissioning is scheduled for Q4 FY26. Stage 2 upgrade works are expected to be completed and commissioned in late Q2 FY27.”
Vault’s gold production from the KOTH open pit and underground mines and Darlot is expected to average 215,000oz over the next five years, peaking at 235,000oz upon the completion of Stage 2.
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