Name of the Project
King of the Hills (KOTH) gold processing facility expansion.

Location
The Eastern Goldfields region of Western Australia.

Project Owner/s
Intermediate gold producer Vault Minerals.

Project Description
The KOTH openpit and underground gold mines, the Darlot satellite underground mine and the KOTH processing facility form part of the Leonora Operations.

The expansion will increase KOTH’s processing facility capacity to six-million tonnes a year.

Stage 1 includes the installation of a new, fit-for-purpose crushing circuit delivering increased throughput capacity and reduced unit operating costs. Stage 1 also significantly increases wet plant and classification circuit capacity to cater for throughput exceeding seven-million tonnes a year.

Stage 2 mill expansion will focus on the addition of a regrind ball mill, a thickener, increased elution and gravity circuit capacity, and increased tailings discharge capacity. The upgrade will introduce opportunities for further and ongoing debottlenecking and optimisation to increase throughput to between seven- and eight-million tonnes a year.

The full A$172-million investment will be internally funded, aided by rising free cash flows as hedging rolls off.

Potential Job Creation
Not stated.

Net Present Value/Internal Rate of Return
Not stated.

Capital Expenditure
Stage 1 project capital expenditure is expected to be $80-million (inclusive of owner’s costs), with an estimated $8-million forecast to be spent in the 2025 financial year.

Preliminary capital for Stage 2 is estimated at $92-million.

The full A$172-million investment will be funded in house, aided by rising free cash flows as hedging rolls off.

Planned Start/End Date
The project was approved in February 2025. Work is expected to be completed within 15 months from April 2025, with commissioning scheduled for the fourth quarter of 2026.

Latest Developments
Vault Minerals has unveiled an update to its Leonora operating strategy, underpinned by a 33% increase in openpit ore reserves at the KoTH operation and confirmation that it will proceed with a Stage 2 processing plant upgrade.

The company has said the expansion will create a “larger, longer life 2.2-million-ounce openpit ore reserve,” supporting an 18-year operating life and a production outlook of 215 000 oz/y over the next five years, peaking at 235 000 oz/y.

The revised plan will result in throughput capacity increasing by 50%, from five-million tonnes a year currently to 7.5-million tonnes a year late in the second quarter of the 2027 financial year. 

Stage 2’s capital cost is estimated at A$92-million and follows the already-committed A$80-million Stage 1 upgrade. 

The KoTH openpit ore reserve is currently 110-million tonnes at 0.62 g/t for 2.2-million ounces, up from 1.65-million ounces a year earlier. The reserve update follows a remodel using a lower cutoff grade of 0.23 g/t and a higher gold price assumption of A$3 750/oz versus A$2 900/oz previously.

At the mineral resource level, KoTH now hosts 3.4-million ounces in the openpit, based on 116-million tonnes grading 0.91 g/t. This compares to 2.9-million ounces previously, with the new model incorporating a higher gold price (A$4 500/oz vs A$3 500/oz) and a lower reporting cutoff of 0.3 g/t.

Vault has also confirmed progress on site works for Stage 1, with crusher vault excavation largely complete and civil works for new adsorption tanks under way.

Enhancements from the two upgrades include a new crushing circuit, increased tankage, a 9 MW regrind ball mill, improved gravity and carbon-in-leach circuits, and expanded power and tailings capacity.

KoTH underground ore reserves remain unchanged, but will be updated in the first quarter of the 2026 financial year reporting cycle.

Key Contracts, Suppliers and Consultants
GR Engineering Services (project design, scope of work and costing).

Contact Details for Project Information
Vault Minerals, tel +61 8 6313 3800 or email info@vaultminerals.com.