Sumitomo and G Mining Group Back Tintina’s Dos Amigos Copper Project

Sumitomo (OTC Pink:SSUMF,TSE:8053) and Canadian engineering firm G Mining Group acquired a 25 percent stake in Tintina Mines (TSXV:TTS,OTCPL:TNNTF) to advance the Dos Amigos copper-gold project in northern Chile.

Through a 50-50 special purpose vehicle, Sumitomo and G Mining subscribed for US$34.5 million of a US$65.5 million private placement issued by the Toronto-listed developer.

The capital injection enabled Tintina to consolidate 100 percent ownership of the Dos Amigos project and fund development through a final investment decision. The transaction yields an effective 12.5 percent economic interest in the mine for Sumitomo.

The open-pit Dos Amigos project, located roughly 130 kilometers northeast of La Serena in Chile’s Atacama Region, recently completed a preliminary economic assessment. The 2026 study outlined an estimated 25-year mine life with a daily processing capacity of 35,000 metric tons. Annual production is targeted at 37,000 metric tons of copper and 57,000 ounces of gold.

The site sits at a relatively low elevation and will leverage existing transportation and power infrastructure from surrounding operations. Total life-of-mine production is projected at 900,000 metric tons of copper and 1.4 million ounces of gold.

Sumitomo partnered with G Mining to navigate industry-wide cost and scheduling overruns. The firm brings a track record of delivering mines on time and within budget, including Newmont’s (NYSE:NEM,ASX:NEM) Merian mine and Lundin Gold’s (TSX:LUG,OTCQX:LUGDF) Fruta del Norte.

Sumitomo’s capital deployment in the Atacama Region coincides with a recent regulatory push by the Chilean and Argentine governments to unlock stranded copper assets in the exact same geographic belt.

Officials from both countries recently convened in Santiago to activate the 1997 Mining Integration and Complementation Treaty. The bi-national agreement establishes concrete rules for sharing infrastructure and resources across the Andes Mountains, targeting projects whose deposits straddle Argentina’s San Juan province and Chile’s Atacama region.

The newly approved protocols cover the Vicuña, NexoAndino, and Filo Sur projects, advancing a legal framework designed to unlock more than US$20.7 billion in copper investment.

This provides Argentine projects access to Chilean ports and the world’s largest copper-producing supply chain.

The treaty revival materialized under Chilean President Jose Antonio Kast and Argentine President Javier Milei. Since March 2026, Chile has received more than US$24.3 billion in mining projects for environmental review.

Concurrently, Argentina approved seven copper projects totaling US$22 billion under its Large Investment Incentive Regime (RIGI), which guarantees 30 years of tax and currency stability.

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Securities Disclosure: I, Giann Liguid, hold no direct investment interest in any company mentioned in this article.