Osisko Gold Confirms High-Grade Proserpine Target Near Cariboo Project

• Osisko Gold Group confirmed high-grade gold structures at its Proserpine target, expanding the known mineralized footprint near the permitted Cariboo deposit.
• The initial drilling program intersected significant grades, including 95.93 g/t Au over 4.60 m, indicating potential for bulk mining methods.
• Management plans to resume drilling of an additional 26,500 meters to test a broader 6.0 km x 1.0 km anomaly.

Osisko Gold Group Inc. has reported initial diamond drilling results from its Proserpine regional greenfield target, located approximately seven kilometres southeast of the Cariboo Gold deposit in central British Columbia. The recent exploration program, which completed 6,463 metres in 14 holes between February and May 2026, has successfully confirmed high-grade gold structures and broader lower-grade zones. These findings suggest significant potential for open-pit mining operations to complement the existing permitted underground mine at Cariboo.

The drilling campaign has effectively expanded the known mineralized footprint at Proserpine to roughly one kilometre along strike by half a kilometre in width. Gold mineralization was encountered from near surface to depths beyond 400 metres, and the system remains open in all directions. With all holes that reached target depth intersecting mineralization, the company has moved forward with plans to further define the system's scale and extent.

Highlight intercepts from the program include 95.93 grams per tonne of gold over 4.60 metres at a vertical depth of 71 metres. Another significant intersection recorded 5.46 grams per tonne of gold over 8.60 metres at a vertical depth of 77 metres. These results underscore the exploration potential to extend the mine life and resource base for the broader Cariboo Gold Project.

Chris Lodder, President of Osisko Gold, stated that the results highlight the potential for a significant new gold mineralized system of scale located only seven kilometres from the Cariboo Gold deposit. The drilling has intersected high-grade structures showing similarities to those at Cariboo, but also contains areas with broader lower-grade mineralization that may indicate potential for bulk mining methods.

To date, drilling has broadly tested an area measuring approximately 1.0 km x 0.5 km within a larger target of 6.0 km x 1.0 km gold-in-soil and rock anomaly. For context, the currently defined Cariboo Gold deposit extends approximately 4.0 km along strike by 0.5 km in width. This comparison underscores the substantial exploration potential that remains to be tested at Proserpine.

Following a seasonal hiatus, drilling of an additional 26,500 metres is resuming, initially with three rigs. The company plans to increase drill density at Proserpine Southeast and begin first-pass drilling at Proserpine Northwest. This expansion is designed to test the full extent of the anomaly and further define the grade and geometry of the mineralization.

How Does Proserpine Impact Cariboo's Development?

The Proserpine target is part of the broader Cariboo Gold Project property boundary in central British Columbia. The Cariboo Gold Project is a permitted, feasibility-stage asset spanning approximately 186,740 hectares in the Wells-Barkerville mining camp. In late 2024, the project secured key permits under the Mines Act and Environmental Management Act, cementing its shovel-ready status.

Current exploration efforts are focused on the central southeast limits of the prospect area, following up on promising results from 2019-2020 campaigns. Less than half of the Proserpine strike-length has been drill-tested to date. An aggregate total of 10,497 metres of exploration drilling was completed between 2018 and 2020, with new campaigns aimed at expanding the known mineralized zones.

The Cariboo project hosts probable mineral reserves of 2.071 million ounces of contained gold, alongside substantial measured, indicated, and inferred resources. A 2025 feasibility study envisions a scalable underground operation expected to produce about 1.89 million ounces of gold over a 10-year life. The project boasts an after-tax net present value of $943 million, highlighting the economic significance of any resource growth.

What Is the Market Reaction to the Discovery?

National Bank Financial analyst Don DeMarco noted that while the exceptional grades are notable, the scale of the discovery is more significant. He described the results as a proof-of-concept for significant resource growth, noting that the target remains largely untested. The stock surged 12.2% to $3.83, valuing the company at about $1.2 billion.

DeMarco stated that the first batch of intercepts provides an encouraging proof-of-concept that Proserpine could become a meaningful contributor to future resource growth at Cariboo. He added that the more important takeaway is the scale, where drilling has defined mineralization over only a small portion of a much larger target that remains open in all directions.

Proserpine is one of several regional targets being tested to identify additional deposits. Some 26,500 metres of drilling are planned at Proserpine, initially with three rigs. Results to date have expanded the footprint of known mineralization at Proserpine to about 1 km along strike by 500 metres in width.

Other drilling highlights include hole PSP-26-009, which cut 5.5 metres of 3.17 grams gold from 408 metres downhole, and hole PSP-26-003, which intersected 12.4 metres of 1.46 grams gold from 367 metres depth. These results complement Osisko’s main Cariboo project, which hosts a permitted underground mine with a 2025 feasibility study projecting 1.89 million ounces of gold over a 10-year life at an after-tax net present value of $943 million.

Construction work on the Cariboo project has been advancing while underground drilling continues to refine the mine plan. The discovery at Proserpine offers a strategic opportunity to potentially add open-pit mining capacity to the existing underground operation. This dual-method approach could significantly enhance the project's overall output and longevity. The resumption of aggressive drilling signals management's confidence in the target's potential to become a major contributor to the company's resource base.