Osisko Metals files NI 43-101 report on Gaspé Copper

TORONTO, May 29, 2026 (GLOBE NEWSWIRE) -- Osisko Metals Incorporated (the " Company " or " Osisko Metals ") (TSX: OM; OTCQX: OMZNF; FRANKFURT: OB51) is pleased to announce the filing on SEDAR+ of a technical report titled "NI 43-101 Technical Report on the Gaspé Copper Project with an Updated Mineral Resource Estimate for the Copper Mountain Deposit, Quebec, Canada" dated May 28, 2026 (with an effective date of January 17, 2026) (the " Technical Report "), in accordance with National Instrument 43-101 – Standards of Disclosure for Mineral Projects (" NI 43-101 "). The Technical Report was prepared by PLR Resources Inc. (" PLR "), G Mining Services Inc. (" G Mining "), and Synectiq Inc. (" Synectiq "), and supports the disclosure contained in the news release of the Company dated April 14, 2026, titled "Osisko Metals Announces Significant Increase in Mineral Resources at Gaspé Copper" (the " April News Release "). Pursuant to subsection 4.2(5)(b) of NI 43-101, the Company confirms that there are no material differences between the Technical Report and the April News Release.

The mineral resource estimates for all categories, including tonnages, grades (copper, molybdenum, silver, and copper equivalent), contained metal, and all underlying technical parameters and assumptions, are identical in the Technical Report and the April News Release. No reconciliation of differences is required. Updated Mineral Resource Estimate – Copper Mountain Deposit The Technical Report presents the updated mineral resource estimate (the " 2026 MRE ") for the Copper Mountain deposit at the Gaspé Copper Project (the " Project "), located on the Gaspé Peninsula of Eastern Québec, adjacent to the municipality of Murdochville.

The 2026 MRE was prepared by Pierre-Luc Richard, P.Geo., of PLR, with contributions from François Le Moal, P.Eng., of G Mining for cut-off grade