Osisko Gold Reports Final Results from its Lowhee Zone Infill Program at the Cariboo Gold Project

TORONTO, July 23, 2026 (GLOBE NEWSWIRE) -- Osisko Gold Group Inc. (NYSE: OGG, TSXV: OGG) (" Osisko Gold " or the " Company ") is pleased to announce final results and reconciliation analysis of its previously completed infill drilling program (the " Infill Program ") in the Lowhee Zone of the Company's permitted, 100%-owned Cariboo Gold Project (the " Project "), located in central British Columbia, Canada. The results of the Infill Program have contributed to an improved understanding of spatial controls and local variability of vein corridors in the Lowhee Zone and, on a local short-term resource model basis, have broadly validated and further refined the underlying model assumptions. Following completion of the Infill Program, Appian Capital Advisory is completing its review of the underlying scientific and technical data.

Subject to the completion of Appian Capital's review and sign-off and the satisfaction of other applicable conditions, the Company anticipates satisfying the technical conditions precedent applicable to the remaining undrawn US$350 million under the senior secured project loan facility in Q3 2026. Model Reconciliation Analysis An aggregate total of 17,072 metres of infill drilling in 185 diamond drill holes were completed in 2025 and 2026 and incorporated into this study. Two areas were targeted in the Lowhee Zone that contained this drilling: Zone 1, comprising approximately 11,925 metres infill drilled on 10-metre spacing in an area on the 1260 elevation level, and Zone 2, comprising the remaining holes drilled from an area on the 1290 elevation level (see Figure 1 ).

Together, these areas formed the basis of a preliminary internal reconciliation analysis exercise against the existing resource block model (the " Reconciliation Analysis "). The program was designed as a systemic grid infill drilling campaign targeting both planned stope ar