Highlights

  • Ausenco-led Scoping Study delivers a pre-tax NPV7 of A$716M (Spot Case) and A$542M (Base Case) for the Mt Carrington Project in NSW.
  • The 19-year mine life targets 373,000 oz Au and 9.91 Moz Ag at a first-Quartile AISC of A$1,061/oz Au (Spot Case, net of silver Credit), with initial Capital of A$220.5M.
  • LGM shares fell 18.9% to $0.150 on the day of the announcement, reflecting broader market caution despite the project's cyanide-free flotation flowsheet and extensive brownfield infrastructure.

Legacy Minerals Holdings Limited (ASX:LGM) endured a sharp selloff on 4 May 2026, with its share price declining 18.9% to close at $0.150 — a fall of $0.035 on the day. Volume reached 2,032,900 shares, elevated relative to typical trading activity, as investors digested the company's comprehensive Scoping Study for the Mt Carrington Project in New South Wales. The bid/offer spread at close was $0.145–$0.150, with the company's Market Capitalisation sitting at approximately $37.02 million. The decline is notable given the headline metrics of the study, and underscores the gap that often exists between project-level Economics and near-term Equity sentiment for early-stage development companies.

The Mt Carrington Scoping Study: A Detailed Look

The Scoping Study, led by Ausenco and supported by Mining Plus, was released to the ASX on 4 May 2026. Under the Spot Case — which assumes a gold price of A$6,500/oz and silver at A$105/oz — the study reports a pre-tax NPV at a 7% discount rate of A$716 million, an internal rate of return (IRR) of 38%, and a payback period of 32 months from first production. Under the more conservative Base Case (Au A$5,950/oz, Ag A$85/oz), those figures moderate to a pre-tax NPV7 of A$542 million, an IRR of 32%, and a 36-month payback. The life-of-mine (LOM) pre-tax free Cash Flow is estimated at A$1,597 million (Spot Case) and A$1,247 million (Base Case).

The financial model is built around a 1 million tonne per annum (Mtpa) open-pit operation spanning 19 years. Over that period, the operation is expected to produce an average of 21,420 oz Au and 568,707 oz Ag per annum, with production peaking at 31,934 oz Au and 845,355 oz Ag in a single year. Gold and silver combined represent the entirety of the Revenue base in this study, with no credits assumed for copper, lead, or zinc — commodities that form a meaningful part of the broader 34.4 Mt resource base.

Mining and Processing Approach

The Mining strategy is conventional and low-risk: a contract Mining model deploying open-pit drill-blast-load-haul methods across eight adjacent shallow pits — Strauss, Kylo, Lady Hampden, Guy Bell, Carrington, Silver King, White Rock and Red Rock. The strip ratio stands at 3.06:1 on a plant feed basis, which is considered manageable for an Australian gold-silver operation. Mining Plus completed pit optimisation using the Lerchs-Grossman algorithm in Whittle software, arriving at a combined cut-off grade of 0.57g/t AuEq and a plant feed of 17.04 Mt at 0.87g/t Au and 21.45g/t Ag.

A significant differentiator in this study is the adoption of a cyanide-free flotation flowsheet — a notable departure from the carbon-in-leach processing used in earlier historical studies and prior operations at the site during the late 1980s and early 1990s. The processing circuit achieves LOM weighted-average recoveries of 78% for gold and 84% for silver, producing a bulk Au-Ag sulphide concentrate for third-party refinery offtake. The flotation approach is designed to carry conventional regulatory expectations and offers operational flexibility, particularly relevant given the multi-pit, campaigned nature of feed delivery.

Capital Cost and Brownfield Advantage

The initial Capital expenditure estimate is A$220.5 million, encompassing A$106.8 million for the processing plant, A$24.0 million for an off-site 32 kV overhead powerline grid connection, A$25.9 million for EPCM and commissioning, and a contingency of A$35.5 million (approximately 19% on base cost). The scoping-level accuracy is cited at -30% to +45%, consistent with industry standards for studies at this stage. Sustaining Capital for tailings storage Facility lifts adds a further A$6.7 million in Year 4.

Mt Carrington's brownfield credentials represent a material derisking Factor. The site retains sealed road access from the Drake-Bruxner Highway route, a cleared and stabilised plant footprint, existing tailings storage Facility and water dams, rehabilitated pits, and 11 kV grid power infrastructure. These Assets, accumulated from the site's prior operating history, substantially reduce both the Capital requirements and the timeline risks typically associated with greenfield developments of comparable scale. The study notes that no camp accommodation is required, as the operation is planned as drive-in/drive-out from nearby regional towns.

Resource Base and Exploration Upside

The global JORC 2012 Mineral Resource Estimate (MRE) for Mt Carrington totals 34.4 Mt at 104.7g/t AgEq, containing approximately 653,000 oz gold, 24.3 Moz silver, 20 kt copper, 33 kt lead, and 146 kt zinc. Critically, the current Scoping Study production target draws on only 17.04 Mt of this resource — roughly half the total. The remainder, including significant silver-rich deposits such as White Rock North (5.4 Moz AgEq) and approximately 180 kt of combined zinc-lead-copper mineralisation, is not incorporated into this study's production target or financial model. This creates a tangible pathway for resource-driven project upscaling.

In terms of resource confidence, approximately 46% of the LOM production target is classified as Indicated and 54% as Inferred. However, during the first 11 years of the Mining schedule, the Indicated proportion increases meaningfully to 71%. The company has flagged a targeted drilling programme ahead of the Pre-Feasibility Study to convert Inferred to Indicated resources in Stage 1 and Stage 2 pit footprints.

Operating Cost Structure and Price Sensitivity

LOM average operating costs are estimated at A$65.72 per tonne of plant feed, comprising A$27.60/t for Mining, A$29.95/t for processing, and A$8.17/t for general and administration. These unit costs translate to a Spot Case AISC of A$1,061/oz Au (net of silver by-product credits), which the company positions as first-Quartile on a global basis. Under the Base Case, AISC is A$1,545/oz. The Margin between the Spot Case gold price assumption and AISC underscores the Operating Leverage inherent in the project.

The study also quantifies Commodity price sensitivity: each additional US$1/oz in the silver price adds an estimated A$13 million in LOM pre-tax Cash Flow and A$6 million to NPV7, while each additional US$100/oz in the gold price implies A$50 million of additional LOM Cash Flow and A$26 million of NPV uplift. With the company's $8 million cash balance cited as sufficient to fund ongoing study work, Legacy Minerals intends to progress directly to a Pre-Feasibility Study.

Key Risks and Next Steps

The Scoping Study identifies several risks that merit investor attention. These include orebody variability across eight pits, which could create concentrate specification challenges for offtakers; the absence of hydrology and dewatering assessments, which may add to future Capital and operating costs; and limited closure planning at the current study stage. Geochemical characterisation of potentially acid-forming waste materials remains outstanding, as does project-specific geotechnical work — the current slope stability parameters are based on Western Australian goldfield analogues rather than site-specific data.

Funding risk is also flagged, given that the A$220.5 million peak drawdown requirement will need to be arranged via Debt, Equity, or alternative financing structures on terms yet to be negotiated. Following the Scoping Study, Legacy Minerals has outlined a clear workstream heading into the Pre-Feasibility Study, including resource conversion drilling, metallurgical variability testing, geotechnical drilling, hydrology modelling, tailings Facility design review, and engagement with potential concentrate offtakers.

Conclusion

Legacy Minerals Holdings' Mt Carrington Scoping Study presents a substantive development case anchored by competitive operating costs, a long mine life, and meaningful brownfield advantages. Despite the project's headline NPV metrics and the company's first-Quartile AISC positioning, LGM shares fell sharply on release day — a dynamic that reflects both the early-stage nature of the project and the substantial funding journey ahead. With approximately half the mineral resource yet to be incorporated into a production target, and multiple study workstreams still to be completed before a final Investment decision can be made, the path from Scoping Study to production remains multi-year and Capital intensive. The company's progress toward a Pre-Feasibility Study will be the next key catalyst for the market to monitor.