Aldebaran and Centauri report significant increase in mineral resources at Rio Grande gold-copper project, Salta, Argentina
Aldebaran Resources Inc. [TSXV: ALDE, OTCQX: ADBRF] and subsidiary Centauri Minerals Inc. reported results of an updated mineral resource estimate for the Rio Grande gold-copper project in Salta Province, Argentina (the MRE).
Highlights: Indicated Resources containing 1.45 million ounces of gold, 384,000 tonnes of copper and 12.7 million ounces of silver; 153.7 million tonnes grading 0.29 g/t gold, 0.25% copper and 2.6 g/t silver.
Inferred Resources: 1.55 million ounces of gold, 420,000 tonnes of copper and 17.8 million ounces of silver; 220.8 million tonnes grading 0.22 g/t gold, 0.19% copper and 2.5 g/t silver.
Mineralization is still open in several directions, with significant porphyry potential beneath the current resource, with historical drilling hitting 257.2 metres of 1.20 g/t gold, and 0.53% copper in porphyry dykes.
Sam Leung, CEO and a director of Centauri, commented: “This new mineral resource estimate is fresh evidence that encourages modern exploration and future studies on the Rio Grande gold-copper project. With no drilling or targeting programs since 2012, Centauri now has the exciting opportunity to apply modern geophysical and geochemical tools ahead of future drilling programs on a project that already contains a substantial mineral inventory. With this resource in hand, a drill program planned for later this year and five additional exploration projects in our portfolio, Centauri is well set up to move forward to becoming a public company in the first half of 2026.”
Dr. Kevin B. Heather, Chief Geological Officer of Aldebaran Resources and Technical Advisor to Centauri, commented: “I have been directly involved in the exploration at the Rio Grande gold-copper project since 2004 and we have always felt the project needed additional exploration to realize its full potential. The MRE reported here marks a significant milestone in the resurrection of the project, and I look forward to working with the Centauri team to unlock significant value in the future.”
SLR Consulting (Canada) Ltd. (SLR) was retained by Centauri to complete a NI 43-101 Technical Report and Mineral Resource Estimate update for the Rio Grande gold-copper project, located in Salta Province, Argentina. The Rio Grande gold-copper property is located in the Altiplano of northwest Argentina and supported by established infrastructure that services regional mines. The property ranges in elevation between 3,700 and 4,700 metres above sea level and is located approximately 260 km west of the city of Salta, 40 km east of the Chilean border, and 9 km from the operating Lindero gold-copper mine. SLR visited the Rio Grande property from December 5 to 7, 2025.
To generate a new resource pit shell, SLR applied new Whittle input parameters to the 2018 resource block model from the NI 43-101 Technical Report and MRE completed by Roscoe Postle Associates Inc. (RPA – since acquired by SLR in 2019) and dated August 17, 2018. There has been no new drilling or trenching work carried out at Rio Grande since 2013.
The Rio Grande project is situated next to the operating Lindero Au-Cu mine and it includes five Mineral Resource areas, ranked by relative contribution: Discovery–Sofía, Central (West and East), North, Southwest, and Seven.
The conceptual processing strategy for Rio Grande includes Heap Leach with SART for oxide material, a combined Heap Leach–SART and flotation approach for transitional material, and flotation for sulphide material. While several viable gold and copper recovery options have been evaluated, the final process flowsheet has not yet been defined and will require additional metallurgical test work. A supporting NI 43-101 Technical Report will be filed on SEDAR within 45 days.
Mineralization at Rio Grande remains open at depth in all of the known zones, particularly in the Sofia and Southwest zones. Drilling completed to date has primarily tested the upper portions of the mineralized system; however, many of the existing drill holes terminated in sulphide mineralization.
In addition, geological interpretation indicates potential for deeper sulphide extensions of the known zones, with historic drilling intercepting mineralization in porphyry dykes whose source has yet to be discovered. This potential is conceptual in nature, and insufficient drilling has been completed to define additional Mineral Resources; however, the observed continuity of alteration and structural controls supports continued exploration.
Centauri is currently working on the legal and commercial requirements to complete the previously announced spinout and go-public event, expected to be completed in the first half of 2026. In addition, Centauri is building out a management and exploration team to advance the exploration portfolio, including developing new drill targets for the Rio Grande project with the intention to commence a drill program on the project in 2026.
Aldebaran and Centauri have executed a definitive share transfer agreement pursuant to which Centauri will acquire all of the shares of Aldebaran Argentina S.A. and Minera El Toro S.A., the Aldebaran subsidiaries that hold the Rio Grande, Aguas Calientes, and four other early-stage mineral exploration properties in Argentina.
In exchange, Aldebaran will receive 40,000,000 common shares (representing approximately 78% of the currently outstanding Centauri shares, with the balance owned by investors in the recent placement by Centauri.