Osisko Gold Stock Surges as Proserpine Drilling Confirms High-Grade Open-Pit Potential

• Osisko Gold Group confirmed high-grade gold intercepts at its Proserpine target, suggesting potential for open-pit mining near its Cariboo project.
• Initial drilling results revealed a new mineralized system with economic characteristics distinct from the underground Cariboo deposit.
• The company secured $450 million in project financing to advance development while expanding exploration at Proserpine.
• Market investors responded positively to the discovery, viewing it as a catalyst for significant resource growth.

Osisko Gold Group Inc. announced the results of its initial diamond drilling program at the Proserpine regional greenfield target, located 7 kilometers southeast of Cariboo. The program, which included 6,463 meters across 14 drill holes completed between February and May 2026, identified a new gold mineralized system. These findings are significant because they confirm the presence of high-grade structures alongside broader zones of lower-grade mineralization that are suitable for bulk, open-pit mining.

Key intercepts from the drilling campaign included 95.93 grams per tonne gold over 4.60 meters at a vertical depth of 71 meters. Another notable result returned 5.46 grams per tonne gold over 8.60 meters at 77 meters vertical depth. The mineralization was encountered from near-surface levels to depths exceeding 400 meters and remains open in all directions. This open-ended nature suggests substantial upside potential as the company continues to expand its exploration footprint.

The known mineralized footprint at Proserpine has expanded to approximately 1.0 kilometer along strike by 0.5 kilometers in width within a larger 6.0-kilometer by 1.0-kilometer anomaly. Chris Lodder, President of Osisko Gold, emphasized that less than half of the strike length has been tested to date. The discovery of siliceous sandstone, believed to be a favorable host for mineralization, further supports the geological model for a district-scale resource.

How does Proserpine complement the Cariboo project development?

The Proserpine discovery offers a distinct economic profile compared to the Cariboo Gold Project, which is primarily planned as an underground operation. Cariboo is permitted and near-construction ready, with a 2025 Feasibility Study projecting 1.89 million ounces of gold over a 10-year mine life and an after-tax net present value of $943 million. The addition of a potential open-pit operation at Proserpine could provide a complementary bulk-tonnage source of gold, potentially extending the mine life and diversifying the production mix.

Osisko has resumed diamond drilling at Proserpine with three active rigs following a seasonal hiatus. The company plans an additional 26,500 meters of drilling to increase drill density at Proserpine Southeast and begin first-pass drilling at Proserpine Northwest. This aggressive exploration campaign is designed to define the full extent of the emerging mineralized system and test new targets within the Cariboo regional property.

What is the financial backing behind Osisko Gold’s expansion?

To fund the development of the Cariboo Gold Project and support ongoing exploration, Osisko Gold secured a $450 million senior secured project loan from Appian Capital Advisory. The credit agreement includes a $100 million initial draw, which enables the company to accelerate pre-construction activities such as infill drilling and detailed engineering. An additional $350 million is available upon meeting specific milestones, providing flexibility for future capital requirements.

The market reacted swiftly to the news, with Osisko Gold’s stock surging 12.2% to $3.83, valuing the company at approximately $1.2 billion. Analysts noted that while the high-grade intercepts are impressive, the scale of the Proserpine target is the primary driver for investor interest. The combination of a permitted near-construction asset and a high-potential greenfield discovery positions Osisko as a compelling intermediate gold producer.

Despite the positive results, the company faces the challenge of defining a consistent resource model across a large area. The Proserpine target remains largely untested, and future drilling results will be critical in determining the economic viability of open-pit mining operations. Osisko’s ability to successfully integrate these two distinct mining methods will be a key factor in its long-term growth strategy.

The resumption of drilling with three rigs underscores the company’s commitment to unlocking the district-scale potential of the Cariboo property. As exploration continues, investors will be closely monitoring the expansion of the mineralized footprint and the refinement of the economic models for both Cariboo and Proserpine. The upcoming drilling results will provide crucial data on the continuity and grade of the Proserpine system.

Osisko Gold’s strategic focus on past-producing mining camps with district-scale potential aligns with the current market appetite for scalable gold assets. The company’s approach of advancing a permitted underground project while exploring high-grade greenfield targets offers a balanced risk-reward profile. Success at Proserpine could significantly enhance the overall value of the Cariboo regional property.