Regis Resources has reinstated the McPhillamys Gold Project Ore Reserve at 56Mt grading 1.1g/t Au for 1.89Moz, supported by a new Pre-Feasibility Study demonstrating strong economics and an alternative tailings strategy. The company targets a Final Investment Decision in H1 2028, pending permitting and judicial review outcomes.
- Ore Reserve reinstated at 56Mt, 1.1g/t Au, 1.89Moz (100% Probable)
- PFS shows 190koz annual production, AISC $1,718/oz, post-tax NPV $1.13bn
- Alternative tailings strategy using filtered tailings co-disposed in Integrated Waste Landform
- State Significant Infrastructure status granted for key project components in NSW
- Final Investment Decision targeted in first half of 2028, subject to approvals and court ruling
McPhillamys Ore Reserve Back in Play After Section 10 Setback
Regis Resources Ltd (ASX:RRL) has reinstated the McPhillamys Gold Project Ore Reserve at 56 million tonnes grading 1.1 grams per tonne gold, containing 1.89 million ounces, all classified as Probable. This follows a comprehensive Pre-Feasibility Study (PFS) that pivots on an innovative tailings management approach, unlocking a path forward after a 2024 Aboriginal heritage declaration stalled the original development plans.
The new PFS, based on filtered tailings co-disposed within an Integrated Waste Landform (IWL) entirely on Regis-owned land, delivers a compelling economic case. At a gold price of A$4,000 per ounce, the project forecasts average annual production of 190,000 ounces over the first nine years, with all-in sustaining costs (AISC) of $1,718 per ounce. Financially, it projects gross revenue of $7.1 billion, a post-tax net present value (NPV) of $1.13 billion at a 5.5% discount rate, and an internal rate of return (IRR) of 21.8%. Total pre-production capital is estimated at $1.08 billion, inclusive of contingencies and capitalised operating costs.
Alternative Tailings Strategy Resolves Heritage Constraints
The project’s original tailings storage facility (TSF) was impacted by a Section 10 declaration under the Aboriginal and Torres Strait Islander Heritage Protection Act, which covered the TSF location. Regis responded by developing the IWL strategy, replacing the conventional valley-fill TSF with a filtered tailings solution that mechanically dewaters slurry into a filter cake for co-disposal with mine waste. This approach avoids the heritage-declared area and maintains the project footprint within accessible land.
Key infrastructure elements including the IWL, water pipeline, and electrical transmission line have been granted State Significant Infrastructure status by New South Wales authorities, streamlining the permitting process. The company is advancing Environmental Impact Statements for these components, with no fatal environmental or social flaws identified to date.
Technical and Financial Metrics Support Development
The PFS incorporates extensive technical inputs from the 2024 Definitive Feasibility Study (DFS), adjusting for the new tailings approach and rebased cost estimates to Q3 FY26. The mine plan envisages a 9.4-year processing life, treating 60.6 million tonnes at 1.0g/t gold, with an 88.1% recovery rate yielding 1.73 million ounces of gold. Mining uses conventional open-pit methods with a strip ratio of 3.4:1.
Capital costs have increased by approximately $74 million compared to the 2024 DFS, mainly due to the IWL design changes and inflationary pressures. Operating costs are similarly elevated, with AISC rising by $138 per ounce to $1,718, reflecting the new tailings management and updated assumptions. Despite these increases, the project remains economically robust, with a post-tax payback period of 3.7 years at the base case gold price.
Permitting and Legal Hurdles Remain Key Milestones
Regis is pursuing a dual-track strategy: continuing legal proceedings to overturn the Section 10 declaration via judicial review while advancing the IWL development pathway. Should the court rule in Regis’ favour, the original TSF approach remains the preferred option. The timing of the court decision remains uncertain.
The company targets a Final Investment Decision (FID) in the first half of 2028, contingent on securing NSW Government approvals for the IWL, water supply pipeline, and electrical transmission line, modifications to existing development consents, federal EPBC Act approvals, and board endorsement of an updated DFS reflecting the chosen tailings strategy.
Community Support and Environmental Commitments
Community sentiment surveys in March 2026 show strong local support, with 71% of respondents in the Blayney area backing the project and only 11% objecting. Regis continues to engage with Registered Aboriginal Parties and incorporates environmental, social, and regulatory considerations into project planning. The project aims for progressive rehabilitation and restoration of disturbed land to agricultural and biodiversity-supporting uses post-closure.
Regis expects to fund initial capital from internal resources, with potential for debt funding if appropriate. Sustaining capital will be self-funded from operating cash flows.
Bottom Line?
Regis has engineered a technically and financially credible comeback for McPhillamys with a new tailings strategy and solid PFS, but the project’s fate hinges on regulatory approvals and a pending Federal Court decision.
Questions in the middle?
- When will the Federal Court deliver its ruling on the Section 10 declaration?
- How might the alternative tailings approach affect long-term environmental and operational risks?
- What upside could satellite deposits like Discovery Ridge add to McPhillamys economics?