Castile’s Rover 1 Scoping Study Highlights $1.07B Pre-Tax NPV with Five Metals

Rover 1 Scoping Study Unveils Strong Multi-Metal Economics

Castile Resources Limited (ASX:CST) has released its 2026 Scoping Study for the 100%-owned Rover 1 IOCG Project in the Northern Territory, spotlighting a compelling economic case anchored by five metal revenue streams. The project, located near Tennant Creek, models an 11-year underground mine life with an initial capital outlay of A$170.5 million and pre-tax NPV8 of A$1.07 billion, delivering an internal rate of return (IRR) of 59% pre-tax and 45% post-tax.

The study notably incorporates bismuth for the first time, a critical mineral whose inclusion boosts projected revenues by around A$600 million. Alongside gold and copper, the primary value drivers, bismuth, cobalt, and high-grade magnetite rounds out the diversified metal portfolio, offering leverage to demand dynamics in critical minerals markets.

Two-Stage Development Balances Flexibility and Value Capture

Castile’s approach divides development into two stages: Stage One focuses on underground mining and processing at the Rover 1 site, producing concentrates of gold, copper, bismuth, cobalt, and magnetite. Stage Two envisages a downstream refining facility at the Middle Arm Sustainable Development Precinct (MASDP) in Darwin, where bulk concentrates will be further processed into final products such as gold doré, 99% copper cathode, cobalt hydroxide for batteries, and refined bismuth.

This staged model allows Castile to leverage early cash flows from concentrate sales while positioning for value-added refining in a government-backed precinct with integrated port, rail, and road infrastructure. The MASDP facility benefits from major Northern Territory government backing and access to renewable energy, aligning with Australia’s critical minerals strategy.

Robust Production and Revenue Profile Across Five Metals

The Scoping Study projects average annual production of 26,800 ounces of gold, 7,200 tonnes of copper, 500 tonnes of bismuth, 300 tonnes of cobalt, and 108,800 tonnes of magnetite concentrate. Over the life of the project, total payable production is estimated at 269,000 ounces of gold, 72,200 tonnes of copper, 5,400 tonnes of bismuth, 2,700 tonnes of cobalt, and 1.1 million tonnes of magnetite.

Financially, gold and copper account for the lion’s share of revenue (A$1.92 billion and A$1.7 billion respectively), with bismuth contributing nearly A$600 million, magnetite A$330 million, and cobalt A$230 million. Operating costs are forecast at A$1.94 billion with royalties of A$304 million, resulting in a project cash flow of approximately A$1.95 billion pre-tax.

Market Dynamics Support Price Assumptions and Strategic Positioning

Castile’s metal price assumptions reflect current market realities and forward-looking fundamentals. Gold prices are projected to rise from a base of US$5,000/oz in 2028 to over US$10,000/oz by 2039, aligned with institutional forecasts of a structural bull market phase. Copper prices, critical to electrification and green infrastructure, are expected to escalate from US$7.50/lb to US$8.60/lb over the same period, reflecting an anticipated structural deficit.

Bismuth, a less transparent but strategically critical mineral, is priced conservatively at US$35/lb initially, with an upside to US$120/kg by 2039, driven by supply concentration in China and growing demand in pharmaceuticals, electronics, and defence. Cobalt prices have surged due to export restrictions from the Democratic Republic of Congo, with a base assumption of US$60,000/t rising to US$106,000/t, supporting the project’s by-product economics. Magnetite commands a premium over standard iron ore due to its high purity and functional properties, with prices forecast to climb from US$210/t to US$285/t FOB Darwin.

Mining and Processing Tailored for Efficiency and Environmental Responsibility

The project plans conventional underground long hole open stoping with paste fill to maximize ore extraction and minimize surface disturbance. Access will be via a decline from a box cut, with mining designed to limit waste and optimize productivity. The processing plant at Rover 1 will crush, grind, and separate the ore into multiple concentrates, including a bismuth concentrate separated early to enhance downstream economics.

Stage 2’s refining facility at MASDP will employ pressure oxidation and solvent extraction/electrowinning to produce final metal products, reducing environmental footprint and adding value. Tailings management includes paste fill underground and a tailings storage facility designed to contain potentially acid-forming waste, reflecting Castile’s commitment to sustainable operations.

Funding Pathways and Next Steps

Castile is poised to leverage the Scoping Study’s strong results to advance funding discussions. The company estimates pre-production funding requirements around A$171.6 million, with potential capital sources including traditional debt and equity, metal streaming, and offtake agreements. Informal talks with financiers have indicated interest, though no formal commitments have been made.

The company plans to complete a Bankable Feasibility Study (BFS) later in 2026, incorporating final bismuth extraction test results and detailed engineering. Environmental Impact Statements and permitting are targeted for submission in late 2026, with construction anticipated to commence in 2027 and first production by 2028.

Strategic and Regional Significance

Rover 1’s multi-metal profile positions it as a key contributor to Australia’s critical minerals ambitions, particularly with the inclusion of bismuth, newly recognised by the Northern Territory government as a critical mineral. The project’s proximity to Tennant Creek and integration with Indigenous land agreements reflect a strong focus on local community benefits and environmental stewardship.

Castile’s Executive Chair and MD Mark Hepburn highlighted the project’s “remarkable earning power” and the flexibility afforded by the staged development, underscoring the company’s commitment to responsible mining and value maximisation for stakeholders.