Close of Private Placement for Gross Proceed C$20M

London, October 2nd, 2025 - Orosur Mining Inc. ("Orosur" or the "Company") (TSX-V/AIM:OMI) is pleased to announce the closing of its previously announced and oversubscribed "best efforts" private placement offering (the "Offering") for aggregate gross proceeds of approximately C$20,000,000, which includes the full exercise of the agents' option for gross proceeds of C$2,000,000. Under the Offering, the Company sold an aggregate of 58,823,530 common shares of the Company (the "Shares") at a price of C$0.34 per Share (being approximately GBP £0.1809 at an exchange rate of GBP £1.88 to CAD).

Red Cloud Securities Inc. ("Red Cloud"), lead agent and sole bookrunner, and Paradigm Capital Inc. (together with Red Cloud, the "Agents") acted as agents in connection with the Offering. In consideration for their services, the Agents received a cash commission of C$809,995.80. Turner Pope Investments (TPI) Ltd, Greenwood Capital Partners Limited (collectively, the "U.K. Brokers") and the Company's Nominated Adviser, SP Angel Corporate Finance LLP ("SP Angel"), acted as brokers in connection with a portion of the Offering in the United Kingdom. In consideration of their services, the U.K. Brokers and SP Angel received aggregate cash commissions and fees of £274,807.44 (equivalent to C$516,638).

In accordance with National Instrument 45-106 - Prospectus Exemptions ("NI 45-106"), 36,764,706 Shares were sold to purchasers resident in Canada pursuant to the listed issuer financing exemption under Part 5A of NI 45-106 as amended by Coordinated Blanket Order 45-935 - Exemptions from Certain Conditions of the Listed Issuer Financing Exemption. Such Shares are not subject to a hold period under Canadian securities laws.

Application has been made for the 58,823,530 Shares, which rank pari passu with the existing common shares in issue, to be admitted to trading on AIM ("Admission"). It is expected that Admission will become effective and dealings will occur at 8:00 a.m. (UK time) on or around October 3rd, 2025.

The closing of the Offering remains subject to the final approval of the TSX Venture Exchange.

Related Party Transaction

As part of the Offering, 1832 Asset Management L.P. ("1832") through investment funds it advises has subscribed for 4,412,000 Shares. The participation in the Offering by 1832, a substantial shareholder in the Company, constitutes a related party transaction pursuant to AIM Rule 13 of the AIM Rules for Companies and within the meaning of TSX-V Policy 5.9 (the "Policy") and Multilateral Instrument 61-101-Protection of Minority Security Holders in Special Transactions ("MI 61-101") adopted in the Policy. The Company intends to rely on the exemptions from the formal valuation and minority shareholder approval requirements of MI 61-101 contained in sections 5.5(a) and 5.7(1)(a) of MI 61-101 in respect of related party participation in the Offering as neither the fair market value (as determined under MI 61-101) of the subject matter of, nor the fair market value of the consideration for, the transaction, insofar as it involves interested parties, has exceeded 25% of the Company's market capitalization (as determined under MI 61-101). The Board, all of whom are considered Directors independent of the Offering, consider, having consulted with the Company's Nominated Adviser, SP Angel Corporate Finance LLP, that the participation by 1832 is fair and reasonable insofar as the shareholders of the Company are concerned.

Following the closing of the Offering, 1832 will have a beneficial interest in 44,027,000 Shares, representing approximately 11.5% of the issued and outstanding share capital of the Company.

Total Voting Rights

Following the closing of the Offering and exercise of warrants totaling 581,500 from the Company's block listing announced January 8, 2025 for a total consideration of C$145,375 and for the purposes of the Disclosure Guidance and Transparency Rules, the Company will have 385,163,924 Shares in issue. Shareholders may use this figure as the denominator for the calculations by which they will determine if they are required to notify their interest in, or a change to their interest in, the issued share capital of the Company.

Neither TSX-V nor its Regulation Services Provider (as that term is defined in policies of the TSX-V) accepts responsibility for the adequacy or accuracy of this release.

About Orosur Mining Inc.

Orosur Mining Inc. (TSXV: OMI; AIM: OMI) is a minerals explorer and developer currently operating in Colombia, Argentina and Nigeria.