Mr. Sean Roosen reports

OSISKO DEVELOPMENT REPORTS FIRST QUARTER 2024 RESULTS

Osisko Development Corp. has released its financial and operating results for the three months ended March 31, 2024.

First quarter 2024 highlights

Operating, financial and corporate updates:

• 619 ounces of gold sold by the company from operating activities in the first quarter, comprising 585 ounces of gold sold from the Trixie test mine, and the balance from the Cariboo gold project by processing stockpiles at a third party processing facility;
• $1.8-million in revenues ($3.5-million in Q1 2023) and $2.0-million in cost of sales ($4.4-million in Q1 2023) generated from operating activities in fourth quarter;
• On Feb. 2, 2024, the company announced that Francois Vezina resigned from his position as senior vice-president, project development, technical services and environment, effective as of March 1, 2024, to pursue outside interests in the mining sector;
• On March 4, 2024, the company announced that the company, as guarantor, and Barkerville Gold Mines Ltd., its wholly owned subsidiary, as borrower, entered into a credit agreement dated March 1, 2024, with National Bank of Canada in connection with a $50-million (U.S.) delayed-draw term loan; the credit facility will be exclusively used to finance continuing detailed engineering and preconstruction activities at the Cariboo gold project; during the quarter, $25.0-million (U.S.) ($33.9-million) was drawn under the credit facility, net of $700,000 (U.S.) ($900,000) of fees;
• As at March 31, 2024, the company had approximately $57.5-million in cash.

Cariboo gold project -- British Columbia, Canada (100 per cent owned):

• Permitting progress: receipt of the environmental assessment certificate in October, 2023, concluded the EA process for the Cariboo gold project, which was launched in October, 2019; a joint permit application for the B.C. Mines Act and Environmental Management Act is in progress:
  • Through four rounds of review from the mine review committee, the company responded to, addressed and closed over 1,800 comments from various stakeholders; the JPA review process is nearing completion, and the mine review committee has begun drafting the B.C. Mines Act and Environmental Management Act permits and subsequent reports;
  • With the signed process charter and agreed-upon schedule with the Major Mines Office, the company anticipates completing its permit application referral at the end of second quarter 2024 and, subsequently, receiving final permits in third quarter 2024;
  • The company continues to explore financing options, including fully financed solutions for the Cariboo gold project;
• Preconstruction activities: on March 1, 2024, the company secured a $50-million (U.S.) credit facility to be exclusively used to finance continuing detailed engineering and preconstruction activities at the Cariboo gold project; during Q1 2024, the company commenced an underground development drift from the existing Cow portal into the Cariboo gold project's mineral deposit at Lowhee zone under an existing provincial permit; the objective is to reach the orebody and extract a 10,000-tonne bulk sample of mineralized material for further ore sorter testing; the company anticipates completing the bulk sample by the end of fourth quarter 2024.

Tintic project -- Utah, United States (100 per cent owned):

• 2023 Trixie exploration program: during Q1 2024, the company disclosed the remaining assay results from 14 diamond drilling holes and chip samples from new development areas as part of its 2023 exploration program at Trixie; select assay results highlights included (see news release dated Feb. 22, 2024):
  • 66.04 grams per tonne gold and 167.64 g/t silver over 8.99 metres in hole TRXU-DD-23-072A (1.93 troy ounces per short ton Au and 4.89 oz/t Ag over 29.50 feet);
• Big Hill porphyry target drilling: an initial regional surface diamond drilling campaign to test for copper-gold-molybdenum porphyry mineralization potential, namely in the Big Hill area, commenced in early December, 2023; an initial 2,913 m (9,557 ft) were drilled in two holes as phase 1 of the surface diamond drilling program:
  • The company completed its initial surface drilling program testing the porphyry target at Big Hill in early May, 2024; as previously disclosed, the first drill hole was completed to a depth of 1,297 m (4,257 ft) when it transitioned out of the prospective alteration zone; the second drill hole was repositioned at a modified angle and completed to a depth of approximately 1,615 m (5,300 ft);
  • The company expects to provide an exploration update, including any material assay results, on the preliminary drilling program in second quarter 2024, as appropriate;
• 2024 Trixie mineral resource estimate: on March 15, 2024, the company released an updated MRE for the underground Trixie deposit, which was included in the subsequently published Tintic technical report; the 2024 Trixie MRE incorporated an additional 1,674 underground chip samples over 1,678 m (5,507 ft) of underground development, and 7,385 m of drilling (24,229 ft) in 122 holes completed since the initial Trixie MRE, with an effective date of Jan. 10, 2023; the 2024 Trixie MRE comprises:
  • Measured resources of 119,847 tonnes grading 27.36 g/t Au and 61.73 g/t Ag, for a total of 105,437 ounces Au and 237,868 oz Ag;
  • Indicated resources of 124,743 tonnes grading 11.17 g/t Au and 59.89 g/t Ag, for a total of 44,811 oz Au and 240,211 oz Ag;
  • Inferred resources of 201,603 tonnes grading 7.80 g/t Au and 48.55 g/t Ag, for a total of 50,569 oz Au and 314,678 oz Ag.

Exploration target potential: The company continues to advance rehabilitation at the 750 level to allow for further underground diamond drilling to test for the downdip extent of the 756 zone and the porphyry target below Trixie. Data compilation work is continuing and is anticipated to generate additional exploration targets.

San Antonio gold project -- Sonora state, Mexico (100 per cent owned):

• Following completion of processing of the remaining stockpile inventory from the heap leach pad in Q3 2023, the San Antonio gold project was placed into care and maintenance, with no production anticipated henceforth.
• The company awaits next steps from the government of Mexico with respect to the permitting process and the status of open-pit mining in the country. The approval process for environmental permits for mining may resume after the conclusion of the governor and presidential elections, which will be held in July, 2024, with the new president taking office in September, 2024.
• Strategic review: As previously disclosed, the company is conducting a strategic review of the San Antonio gold project and has engaged a financial adviser in connection thereof. The strategic review includes, among others, exploring the potential for a financial or strategic partner in the asset or for a full or partial sale of the asset.

Subsequent to Q1 2024:

• On April 26, 2024, the company announced the filing of the Tintic technical report on the 2024 Trixie MRE.

Consolidated financial statements

The company's unaudited interim consolidated financial statements and management's discussion and analysis for the three months ended March 31, 2024, are available on the company's website, and on SEDAR+ and on EDGAR under Osisko Development's issuer profile.

Annual meeting of the shareholders

The company's annual meeting of shareholders will be held in person on May 7, 2024, at 1:30 p.m. Eastern Time, at 1100, Av. des Canadiens-de-Montreal, Suite 300, Montreal, Que., H3B 2S2. Information regarding notice, materials and voting can be found in the management information circular dated March 18, 2024, available on the company's website and on SEDAR+ under Osisko Development's issuer profile.

Qualified person

The scientific and technical information contained in this news release has been reviewed and approved by Maggie Layman, PGeo, vice-president, exploration, of Osisko Development, a qualified person within the meaning of National Instrument 43-101 (Standards of Disclosure for Mineral Projects).

Technical reports

Information relating to the Cariboo gold project and the Cariboo feasibility study is supported by the technical report titled "Feasibility Study for the Cariboo Gold Project, District of Well, British Columbia, Canada," dated Jan. 10, 2023 (amended Jan. 12, 2023), with an effective date of Dec. 30, 2022, prepared for the company by independent representative BBA Engineering Ltd. and supported by independent consulting firms, including InnovExplo Inc., SRK Consulting (Canada) Inc., Golder Associates Ltd. (amalgamated with WSP Canada Inc. on Jan. 1, 2023, to form WSP Canada Inc.), WSP USA Inc., Falkirk Environmental Consultants Ltd., Klohn Crippen Berger Ltd., KCC Geoconsulting Inc. and JDS Energy & Mining Inc. Reference should be made to the full text of the Cariboo technical report, which was prepared in accordance with National Instrument 43-101, and is available electronically on SEDAR+ and on EDGAR under Osisko Development's issuer profile and on the company's website.

Scientific and technical information relating to the Tintic project and the updated mineral resource estimate for the Trixie deposit, and the assumptions, qualifications and limitations thereof, is supported by the technical report titled "NI 43-101 Technical Report, Mineral Resource Estimate for the Trixie Deposit, Tintic Project, Utah, United States of America," and dated April 25, 2024 (with an effective date of March 14, 2024), prepared for the company by independent representatives of Micon International Ltd., being William Lewis, PGeo, and Alan J. San Martin, MAusIMM (CP). Reference should be made to the full text of the Tintic technical report, which was prepared in accordance with NI 43-101, and is available electronically on SEDAR+ and on EDGAR under Osisko Development's issuer profile and on the company's website.

Information relating to San Antonio is supported by the technical report titled "NI 43-101 Technical Report for the 2022 Mineral Resource Estimate on the San Antonio Project, Sonora, Mexico," dated July 12, 2022 (with an effective date of June 24, 2022), prepared for the company by independent representatives of Micon International. Reference should be made to the full text of the San Antonio technical report, which was prepared in accordance with NI 43-101, and is available electronically on SEDAR+ and on EDGAR under Osisko Development's issuer profile and on the company's website.

About Osisko Development Corp.

Osisko Development is a North American gold development company focused on past-producing mining camps located in mining-friendly jurisdictions with district-scale potential. The company's objective is to become an intermediate gold producer by advancing its 100-per-cent-owned Cariboo gold project, located in central British Columbia, Canada, the Tintic project in the historic East Tintic mining district in Utah, United States, and the San Antonio gold project in Sonora, Mexico. In addition to considerable brownfield exploration potential of these properties, that benefit from significant historical mining data, existing infrastructure and access to skilled labour, the company's project pipeline is complemented by other prospective exploration properties. The company's strategy is to develop attractive, long-life, socially and environmentally sustainable mining assets, while minimizing exposure to development risk and increasing mineral resources.

We seek Safe Harbor.