Capstone Copper’s San Pietro acquisition adds copper, gold, iron and cobalt exploration ground to its Atacama portfolio.
By Sonny Rollins
Capstone Copper has agreed to acquire the copper-focused assets covering roughly two-thirds of Chile’s San Pietro copper-gold-iron-cobalt project for US$25 million in Capstone shares, expanding the company’s position in the Atacama mining district.
The transaction includes approximately 16,555 hectares of concessions containing the Rincones and Colla copper deposits and related exploration targets. The assets are being acquired from New Golden Explorations Chile SpA, a joint venture indirectly owned by Golden Arrow Resources and Sociedad de Servicios Andinos.
BNamericas reported the deal on Aug. 25, citing the transaction agreement and company disclosures. Golden Arrow shareholders approved the sale with 98.77% of votes cast in favour at a meeting held on Aug. 21.
The transaction is expected to close in the third quarter, subject to customary conditions, including regulatory approvals and the listing of the Capstone consideration shares on the Toronto Stock Exchange.
Deal at a glance
| Item | Details |
|---|---|
| Buyer | Capstone Copper Corp. and subsidiary Far West Explorations S.A. |
| Asset | Copper-focused concessions at the San Pietro project |
| Interest acquired | Roughly two-thirds of the project’s land package |
| Land area | Approximately 16,555 hectares |
| Consideration | US$25 million in Capstone shares |
| Commodity mix | Copper, gold, iron and cobalt |
| District | Atacama Region, Chile |
| Seller | New Golden Explorations Chile SpA, owned approximately 75.019% by Golden Arrow and 24.981% by Sociedad de Servicios Andinos |
The transaction value equates to approximately US$1,510 per hectare before transaction costs and advisory fees. That is a simple land-area comparison rather than a project valuation, but it provides a useful reference point for tracking mining M&A deals in 2026.
San Pietro adds a copper-focused land package
San Pietro covers approximately 21,000 hectares in the Atacama Region, near Copiapó and within Chile’s established iron oxide-copper-gold, or IOCG, belt.
Capstone’s acquisition is focused on the copper-bearing portion of the property. The company will take control of the concessions containing the Rincones and Colla deposits, along with associated targets that Golden Arrow advanced through drilling and exploration.
The remaining ground, covering more than 9,000 hectares, will stay with Golden Arrow and its joint venture partner. That retained package includes gold-focused targets that Golden Arrow plans to explore under the project’s proposed Atakama Gold identity.
According to the companies’ disclosures, the Rincones and Colla deposits carry an inferred resource estimate of approximately 2.47 billion pounds of copper and 770,000 ounces of gold. The estimate applies to the deposits included in the copper asset transaction. Much of the broader property remains underexplored.
That distinction will matter as Capstone begins its technical and exploration work. San Pietro is not yet an operating mine or a sanctioned development project. Its value to Capstone rests on the potential to expand the company’s exploration pipeline around existing infrastructure, geological expertise and future processing capacity in the Atacama district.
Mantoverde is Capstone’s operating open-pit copper mine in the Atacama Region.
Why the Atacama district matters
Capstone already operates the Mantoverde open-pit copper-gold mine in Atacama. The mine uses truck-and-shovel methods and processes both sulphide and oxide ore to produce copper concentrates and cathodes.
The company owns 70% of Mantoverde, with Mitsubishi Materials Corporation holding the remaining 30%. Capstone says the operation has 32,000 tonnes per day of sulphide mill capacity and 60,000 tonnes per year of copper cathode capacity. It is also advancing the Mantoverde Optimized project, designed to increase sulphide throughput to 45,000 tonnes per day.
San Pietro adds exploration ground to a district where Capstone is already investing in production growth, processing capacity and infrastructure. The company’s Atacama portfolio also includes the fully permitted Santo Domingo copper-iron-gold project, located approximately 35 kilometres northeast of Mantoverde.
Capstone’s operations portfolio includes Mantoverde and Santo Domingo, as well as the Mantos Blancos copper-silver mine in Chile’s Antofagasta Region and operating assets in the United States and Mexico.
The company has described the Mantoverde-Santo Domingo area as an integrated mining district. Its published plans target more than 250,000 tonnes per year of potential low-cost copper production across the district, alongside iron ore and possible cobalt production.
San Pietro is separate from the existing Mantoverde and Santo Domingo mine plans. However, its location and IOCG geology could give Capstone additional options for exploration, future resource growth or potential district-scale development.
Santo Domingo is Capstone’s fully permitted copper-iron-gold development project near Mantoverde.
A strategic fit for Capstone’s copper portfolio
The acquisition reflects a familiar strategy among established copper producers: consolidate prospective ground around operating mines and permitted projects rather than build entirely new regional platforms.
Capstone’s disclosure points to several potential advantages. The company is adding a sizeable exploration package in a known copper-producing region, close to an existing operating mine and a permitted development project. It will also gain access to deposits with a polymetallic profile that includes gold, iron and cobalt alongside copper.
Cobalt is particularly relevant to Capstone’s broader Atacama strategy. The company has been evaluating cobalt recovery from pyrite in the Mantoverde-Santo Domingo district. Its stated approach involves recovering cobalt-bearing pyrite from tailings streams and processing it through upgraded leach and ion-exchange circuits.
There is no indication that the San Pietro acquisition immediately changes Capstone’s production guidance or approved mine plans. The project will require further technical work, exploration, resource evaluation, permitting analysis and capital assessment before any development decision could be made.
The transaction does, however, broaden Capstone’s exposure to future copper supply in Chile. The company’s Santo Domingo project page identifies average annual copper production of 106,000 tonnes during the first seven years of its mine plan and a mine life of more than 19 years. Santo Domingo is being prepared for a sanctioning decision, while detailed engineering and financing work continue.
Seller retains gold exposure
For Golden Arrow, the sale separates the copper-focused concessions from the company’s remaining gold exploration portfolio.
Golden Arrow and Sociedad de Servicios Andinos will retain more than 9,000 hectares of San Pietro ground, including several gold targets identified during exploration over the past year. Golden Arrow has said the transaction proceeds will support expanded exploration on those targets and provide the company with a liquid shareholding in Capstone.
The consideration will be issued entirely in Capstone shares rather than cash. The number of shares will be calculated using Capstone’s volume-weighted average closing price over the 10 trading days before closing, subject to the pricing requirements of the TSX.
Golden Arrow has estimated transaction costs and taxes at approximately US$6.55 million. A portion of the consideration, equivalent to US$750,000, is allocated to advisory fee shares, subject to approval from the TSX Venture Exchange.
The transaction also allows Golden Arrow to focus its exploration budget on gold while maintaining indirect exposure to copper through the Capstone shares it receives.
Closing conditions and next steps
Golden Arrow’s shareholder approval removes one of the principal transaction conditions. The companies must still complete the pre-closing reorganization, obtain the required exchange approvals and satisfy other customary conditions.
The sale involves the transfer of a newly formed subsidiary holding the copper assets. Capstone and Far West Explorations will acquire the shares of that subsidiary from the sellers.
The next stage will be closing and the transfer of the concessions. After that, Capstone is likely to assess the existing geological database, validate the resource estimates and determine how San Pietro fits within its exploration priorities for the Atacama district.
For investors and operators tracking copper, the key issue is not immediate production. It is whether Capstone can convert regional proximity and geological continuity into measurable development advantages over time.
The San Pietro deal therefore adds a new layer to Capstone’s Chile strategy: an exploration-stage copper asset acquired at a modest headline value, positioned near a producing mine and a permitted development project, with additional exposure to gold, iron and cobalt.
Shareable social snippet
Capstone Copper is acquiring roughly two-thirds of Chile’s San Pietro copper assets for US$25 million in shares. The 16,555-hectare package includes the Rincones and Colla deposits and expands Capstone’s Atacama district strategy around Mantoverde and Santo Domingo. Read the full deal breakdown.
For broader market context, see Skillings’ analysis of the copper market and mining M&A premiums and its copper price forecast for 2026.
Sources: BNamericas; Golden Arrow transaction disclosure; Golden Arrow shareholder approval; Capstone Copper operations.