Aldebaran Files PEA on Sedar+ and Announces Termination of the Option Agreement with Nuton Holdings Ltd.

The November 24, 2025, press release from Aldebaran Resources contains two main items. First, the company has filed the NI 43-101 Preliminary Economic Assessment (PEA) technical report for its Altar copper-gold project on SEDAR+. The results of this PEA, which showed robust project economics including an after-tax NPV(8%) of US$2 billion and an IRR of 20.5%, were previously announced on October 30, 2025.

Second, and more significantly, Aldebaran announced the mutual termination of the Option to Joint Venture agreement with Nuton Holdings Ltd., a subsidiary of Rio Tinto. This agreement, originally announced in November 2024, provided Nuton the right to acquire a 20% interest in the Altar project through staged funding. With the termination, Aldebaran now retains 100% of its interest in the project, which is an 80% stake in the Altar project itself.

The filing of a technical report is a routine and expected procedure following the announcement of PEA results and is neutral in isolation. However, the termination of the option agreement with Nuton (Rio Tinto) is a materially negative event that overshadows the positive PEA.

Tracing the company's news provides critical context: - November 2024: Aldebaran announced a massive resource increase and the strategic partnership with Nuton, which was a significant de-risking event, providing both capital (up to US$250 million) and technical validation from a supermajor. The market began to price in this partnership. - April 2025 & September 2025: The company announced two separate delays to the PEA release, both times citing the need to "allow time for Nuton Holdings LLC to complete its review." These delays were early red flags, suggesting potential friction or technical challenges within the partnership. - October 30, 2025: Aldebaran released a very strong PEA, causing the stock to rally to a 52-week high. The market clearly believed the project was advancing well with a strong partner.

The termination of the Nuton agreement fundamentally alters the investment thesis. The loss of a Tier-1 partner like Rio Tinto raises serious questions: 1. Funding: A major, non-dilutive funding source is gone. The Altar project's initial capex is US$1.59 billion, an amount Aldebaran cannot possibly finance on its own. The company's path to funding the next steps, including a Pre-Feasibility Study (PFS), is now uncertain and will likely involve highly dilutive equity raises or finding a new partner, which could be on less favorable terms. 2. Credibility: The exit of a major like Rio Tinto is a significant negative signal. It could imply that Nuton's proprietary leaching technology was not as effective on Altar's mineralization as anticipated, or that they uncovered other technical, social, or jurisdictional risks during their due diligence that made them walk away. 3. Project Timeline: Without a partner and clear funding, the project's timeline, which previously targeted a PFS in H2-2026, is now at high risk of significant delays.

While the company will frame regaining 100% of its interest as a positive, the reality is that they now bear 100% of the funding risk for a massive project. The market had ascribed a premium to Aldebaran for its partnership with Rio Tinto; this premium will now be removed, and a significant risk discount will be applied.

Aldebaran Resources Inc. is a Canadian-based mineral exploration company focused on the Americas. Its flagship asset is the Altar copper-gold project located in the San Juan Province of Argentina, a prolific mining district that hosts other large-scale copper deposits. The company currently holds an 80% interest in Altar. The project is a very large porphyry copper-gold system which the company has advanced significantly, culminating in a 2025 PEA demonstrating its potential to be a long-life, large-scale mining operation. Aldebaran is also in the process of spinning out its other exploration assets in Argentina into a new company, Centauri Minerals Inc.