Aldebaran Resources stock hits high on copper-gold resource boost in Argentina

Aldebaran Resources (TSXV: ALDE, OTCQX: ADBRF) says a significant resource increase makes its Altar project in Argentina one of the world’s largest copper-gold deposits.

Total measured and indicated resources came to 2.4 billion tonnes grading 0.42% copper, 0.07 gram gold per tonne, 1.22 grams silver and 42 parts per million (ppm) molybdenum. The measured and indicated tonnage was double that of a previous resource estimate in 2021. The contained copper was also close to double at 22 billion lb., while the contained gold rose 48% to 5.1 million ounces.

Total inferred resources were 1.22 billion tonnes grading 0.37% copper, 0.04 gram gold, 1.25 grams silver and 45 ppm molybdenum. The tonnage represents a 542% increase over the previous estimate, while the contained copper and gold were 462% and 338% higher respectively.

The resource update, according to Aldebaran’s CEO John Black, represents a major milestone for the Altar copper-gold project after nearly 63,000 metres of drilling. The company has begun working towards Altar’s first preliminary economic assessment, to be completed in the second quarter of 2025.

“With our 2024-2025 drill program just underway and lots of catalysts coming, the future is very bright at the Altar copper-gold project,” Black said.

Aldebaran Resources’ stock set an all-time high of $2.19 on Monday following the resource update. It gained 2.3% on Tuesday morning in Toronto to $2.28 for a market capitalization of $355.6 million. The stock has been as low as 55¢ in the past 52 weeks. 

Porphyry cluster

The Altar project near San Juan forms part of a cluster of world-class porphyry copper deposits near the Argentina-Chile border that includes Los Pelambres with Antofagasta (LSE: ANTO), El Pachón with Glencore (LSE: GLEN) and Los Azules with McEwen Mining (TSX: MUX; NYSE: MUX).

The new resource estimate includes the three main porphyry discoveries (Altar Central, Altar East and Altar United), reported within a single conceptual open pit. These discoveries are part of a cluster of porphyry centres across 7 km of strike length on the property.

Three other mineralized zones (Altar North, QDM and Radio) have been identified to date, but were excluded from the resource estimation.

Kevin Heather, chief geological officer, said the new resource is a validation of an exploration concept the company had in 2017 while doing the original due diligence on the project before acquiring an option to earn-in on the Altar project.

‘We believed there was geological evidence that the gap between Altar Central and Altar East could host significant mineralization that had never been drilled. Fast-forward to today, after seven years of conviction, hard work, and the discovery and definition of the Altar United porphyry,” Heather said.

PFS in 2026

Commenting further on the resource update, Black noted: “Just as important as the size of the deposit, 66% of the resource tonnes are classified as measured and indicated, indicating a very high confidence level in the resource estimate.”

This, he says, will prove very valuable while working towards a prefeasibility study on Altar, which the company plans to complete in the second half of 2026. “This important milestone clearly adds substantial value and positions Altar as one of the very few truly giant copper-gold projects still in the hands of a junior exploration company,” Black stated.

The Altar project was originally held by Rio Tinto (NYSE: RIO; LSE: RIO; ASX: RIO), which completed 2,841 metres of drilling between 1995-2004. The Rio later optioned the project to Peregrine Metals, who subsequently drilled 56,761 metres before being acquired by Sibanye-Stillwater in 2011.

In 2018, Aldebaran, having spun out of Regulus Resources (TSXV: REG) that year, entered an option agreement to acquire an 80% interest in the project. To date, it has earned a 60% interest and is working to formalize the acquisition of the remaining 20% from Sibanye.

Recently, the company partnered up with Nuton, a Rio Tinto technology venture, to advance the Altar project through the coming studies. As part of the agreement, Nuton will provide funding of up to US$250 million in return for a 20% interest.