Vault Minerals has submitted a fully certified Closure Plan Amendment for its Southern Tailings Management Facility, marking a regulatory milestone that supports a planned restart of underground development in Q1 FY27 and gold production in Q1 FY28 at Sugar Zone, Ontario.
- Closure Plan Amendment submitted for Southern Tailings Management Facility
- Ore Reserve of 2.3Mt at 5.4 g/t for 389,000 ounces confirmed
- Infrastructure upgrades and senior leadership recruitment underway
- Tailings facility construction budgeted at C$20 million
- Exploration drilling highlights significant resource upside
Regulatory Milestone Clears Path for Restart
Vault Minerals (ASX:VAU) has taken a decisive step towards reviving its Sugar Zone gold mine in Ontario by submitting a fully certified Closure Plan Amendment (CPA) for the Southern Tailings Management Facility (STMF). This submission follows a thorough technical review and consultation with local First Nations communities, notably the Netmizaaggamig Nishnaabeg, who have publicly supported the milestone as a foundation for the mine's restart.
The Ontario Ministry of Energy and Mines formally invited Vault to lodge the CPA, which will be published for public information before final filing. Concurrently, Vault has received a draft Sewage Environmental Compliance Approval from the Ministry of Environment, Conservation and Parks, further advancing regulatory approvals.
Robust Resource Base and Exploration Upside
Since halting operations in August 2023, Vault has completed an extensive 114,000-metre drilling campaign that has materially upgraded geological confidence at Sugar Zone. The company reports an Ore Reserve of 2.3 million tonnes at 5.4 grams per tonne (g/t) gold, equating to 389,000 ounces, underpinning a seven-year mine life with an average annual production of approximately 50,000 ounces.
The broader Mineral Resource stands at 4.8 million tonnes at 8.0 g/t for 1.23 million ounces, with all three lodes open in multiple directions. This leaves room for further resource conversion and discovery potential, especially as underground exploration is set to resume post-restart.
Infrastructure Upgrades and Operational Readiness
Vault has invested in significant infrastructure refurbishment, including upgrades to underground mine services, surface workshops, and personnel facilities. The restart will employ conventional long-hole open stoping methods targeting a production rate of around 900 tonnes per day.
Mining will initially operate under an owner-operator model, focusing on development for 9 to 12 months to establish access to multiple mining levels. Waste rock from development will support STMF construction, while ore drives will create stockpiles ready for processing when the plant restarts in Q1 FY28.
Processing Capacity and Tailings Management
Processing infrastructure has also been enhanced, including a new two-stage crushing circuit commissioned in 2022 and upgrades to water treatment facilities. The plant is currently aligned with a throughput of 320,000 tonnes per annum but is permitted for up to 550,000 tonnes, with latent capacity to support future expansion.
The STMF, planned as the sole tailings repository over the Ore Reserve life, offers a more capital and operating cost-efficient solution compared to previous methods. Construction activities are slated to begin in the 2026 Canadian summer, including earthworks and infrastructure development, with primary dam construction expected in summer 2027. The dam project is budgeted at approximately C$20 million (A$20.2 million).
Building the Team for Restart
Recruitment of senior site leadership is progressing well, with key appointments across mine management, technical services, commercial, human resources, and environmental functions. Broader operational hiring will ramp up in line with underground development schedules following CPA filing.
Bottom Line?
Vault's regulatory progress and operational upgrades position Sugar Zone for a measured restart, but execution risks remain around final approvals and construction timelines.
Questions in the middle?
- Will the Closure Plan Amendment receive final approval without delay?
- How quickly can exploration convert resource upside into reserve extensions?
- What impact will the owner-operator model have on early development efficiency?