Mr. Claude Dufresne reports

TINTINA MINES COMPLETES STRATEGIC PARTNERSHIP TRANSACTION, CONSOLIDATING 100% OWNERSHIP OF THE DOS AMIGOS (FORMERLY DOMEYKO SULFUROS) COPPER-GOLD PROJECT IN CHILE

Tintina Mines Ltd. has completed the acquisition and financing transactions first announced on June 2, 2026. All conditions to the release of the escrowed proceeds of the company's $91-million private placement of subscription receipts have been satisfied, the escrowed proceeds have been released to the company, the subscription receipts have been exchanged for their underlying securities, and the company has completed the acquisition of the remaining 26.25-per-cent minority interest in Andean Belt Resources SpA (ABR).

Tintina now owns 100 per cent of ABR and, indirectly, 100 per cent of the Dos Amigos copper-gold project, formerly known as the Domeyko sulphuros project, together with approximately $55-million of net proceeds from the offering dedicated to advancing the project toward a final investment decision (FID). Further details of the transactions are set out in the company's news releases dated June 2, 2026, July 2, 2026, July 10, 2026, and Aug. 21, 2026, and in the company's management information circular dated July 30, 2026, each available under the company's SEDAR+ profile.

Completion highlights

• Financing completed -- gross proceeds of approximately $91-million released from escrow, of which approximately $36-million ($26.25-million (U.S.)) financed the minority interest acquisition and approximately $55-million is dedicated to advancing the project toward FID;
• 100-per-cent ownership consolidated -- Tintina now holds 100 per cent of ABR and, indirectly, 100 per cent of the project, with no streams, royalties (other than Chilean state royalties) or offtake commitments in place;
• New shareholder base -- GMC SPV Equity 01 Inc. (the anchor investor), an equal partnership between Sumitomo Corp. and the Gignac family, holds approximately 25 per cent of the issued and outstanding common shares on a non-diluted basis;
• Board reconstituted -- the board of directors of the company now comprises Juan Enrique Rassmuss (chairman), Mathieu Gignac, Koji Watanabe, Stefan Jochum and Vicente Irarrazaval, following the resignation of Carmelo Marrelli;
• New management appointed -- Claude Dufresne has been appointed chief executive officer and Chris Stackhouse has been appointed chief financial officer, in each case effective Aug. 24, 2026; Mr. Rassmuss has stepped down as chief executive officer and continues as chairman, and Jing Peng has ceased to hold the office of chief financial officer;
• Board committees constituted -- the board has established a technical committee to oversee the technical advancement of the project, comprising one representative of the anchor investor, one representative of Mr. Rassmuss, and two representatives of the company, and has constituted the audit committee of the board, comprising Mr. Watanabe, Mr. Jochum and Mr. Irarrazaval;
• Work program launched -- a fully financed program of approximately 50,000 metres of drilling, a feasibility study, and a four-season environmental baseline and permitting program has been launched by the company;
• Project renamed -- the Domeyko sulphuros project has been renamed the Dos Amigos project, reflecting the historical name associated with the property's oxide project and providing continuity with the project's established identity in the region.

Management and directors commentary

Juan Enrique Rassmuss, chairman of Tintina, stated: "Closing this transaction delivers precisely on the needs of the Dos Amigos project -- undivided ownership at the asset level, the capital to carry it to a final investment decision and the partners with the technical depth to build the project. I look forward to continuing in my board role through this next phase of the company's development. The relationships we have built in the Huasco province have taken many years to earn, and continuity with our communities and our people in Chile has been a priority throughout this process."

Claude Dufresne, chief executive officer of Tintina, stated: "We evaluated numerous copper opportunities globally, and Dos Amigos stands out. The project combines scale with exceptional infrastructure in a very well-understood mining jurisdiction, including direct access to a national highway, high-voltage transmission at the property boundary and a brownfield site with a history of mining operations. These attributes provide a strong foundation for development and align directly with G Mining Services' core strengths in engineering, construction and project execution. Subject to the confirmations from our work program, we believe Dos Amigos has the potential to become a relevant copper operation and, over time, a platform for future growth."

Work program

Drilling and resource conversion - the key priority in the near-term will be the conversion of existing inferred resources to the indicated category via 40,000 metres of drilling, with an additional 10,000 metres of geotechnical, hydrogeological, waste characterization and condemnation drilling required to support the feasibility study and permitting workstreams. Drilling is expected to commence at the end of September, 2026, and continue into the first half of 2027, with an updated mineral resource estimate targeted for H2 2027.

Feasibility study -- Tintina intends to proceed directly to a feasibility study rather than an intermediate prefeasibility stage, reflecting the brownfield nature of the site and conventional flowsheet as presented in the 2026 PEA. Engineering and trade-off studies will commence concurrently with the drilling program, and the feasibility study results are targeted for 2028 on completion of all engineering workstreams.

Environment and permitting -- Permitting is the critical path to FID. Accordingly, work on the environmental impact assessment will commence immediately with an environmental baseline spanning a full seasonal cycle of fieldwork on water, air, flora and fauna, heritage, and communities prior to the delivery of the feasibility study. Early engagement with communities and regulators is management's principal focus in managing this timeline. In parallel, Tintina is evaluating water supply scenarios for the project, including the dedicated 63-kilometre raw seawater pipeline contemplated by the PEA, alternative intake sites and pipeline routings, and shared or third party seawater supply arrangements.

Exploration -- Tintina intends to embark on a systematic exploration campaign in 2027 comprising geophysics, surface geochemistry and mapping to explore the 10-kilometre-long trend of porphyry centres on Tintina's concessions. Priority targets include Tricolor, located approximately three kilometres north of the Dos Amigos deposit, where limited historical drilling is interpreted as consistent with a second porphyry centre. Additional porphyry-related alteration zones have been identified within the land package and remain unexplored. Tintina intends to update the market in Q4 2026 with a dedicated announcement relating to the 2027 regional exploration program.

Path to a final investment decision -- Subject to the outcome of the drilling program, the feasibility study, permitting and board approval, Tintina is targeting a final investment decision on Dos Amigos in 2030.

About the Dos Amigos copper-gold project

The project is a copper-gold porphyry deposit located in the Atacama region of northern Chile, held through ABR and now 100 per cent owned by Tintina. The mineral resource estimate and PEA referred to below are as set out in Tintina's independent technical report dated Feb. 2, 2026 (the technical report), prepared in accordance with National Instrument 43-101 -- Standards of Disclosure for Mineral Projects and available under Tintina's SEDAR+ profile. The project was previously referred to as the Domeyko sulphuros project; the change of name is for identification purposes only and does not affect the project's mineral tenure, the technical report or any previously reported scientific or technical information.

PEA highlights

• Location and infrastructure -- Atacama region, northern Chile; approximately 800 metres above sea level; direct access to highway, grid power and coastal export logistics;
• Project status -- brownfield site with prior oxide operations, an established mining footprint and exposed sulphide mineralization;
• Measured and indicated mineral resources -- 100.8 million tonnes 0.35 per cent copper and 0.28 gram per tonne gold;
• Inferred mineral resources -- 256.3 million tonnes 0.34 per cent copper and 0.24 grams per tonne gold;
• PEA mine plan -- 25-year open-pit operation with flotation processing at 35,000 tonnes per day;
• Life-of-mine average annual production -- approximately 37,000 tonnes of copper and 57,000 ounces of gold in concentrate;
• Life-of-mine total production -- approximately 900,000 tonnes copper and 1.4 million ounces gold;
• Exploration upside -- 100-per-cent ABR-owned Tricolor target, located approximately three kilometres north of the Dos Amigos deposit, where early stage drill results are consistent with a second porphyry center; additional resource potential identified within the existing land package.

The PEA is preliminary in nature, includes inferred mineral resources that are considered too speculative geologically to have the economic considerations applied to them that would enable them to be categorized as mineral reserves, and there is no certainty that the results of the PEA will be realized.

Capital structure and securities issued

On exchange of the subscription receipts, the company issued an aggregate of 133,874,114 common shares and 91,265,291 warrants, comprising 45,632,646 warrants exercisable at 80 cents per common share at any time on or before July 9, 2029 (the first warrants), and 45,632,646 warrants exercisable at $1.00 per common share at any time on or before July 9, 2031 (the second warrants). Following the exchange, the company has 283,518,365 common shares issued and outstanding.

All securities issued on exchange of the subscription receipts, and any common shares issuable on exercise of the warrants, remain subject to a statutory hold period expiring on Nov. 10, 2026. Each of the anchor investor and Mr. Rassmuss is subject to a 24-month contractual lock-up from the date of exchange, with customary exceptions, and has granted the other reciprocal rights of first refusal over future dispositions of common shares.

Canaccord Genuity Corp. acted as finder in connection with approximately $17-million of subscription receipts issued under the offering, in consideration for which it received a 5 per cent cash finder's fee from the company.

Incentive awards granted

The board granted an aggregate of 2,857,500 stock options to directors, management and consultants, at an exercise price of $2.10 per common share, in each case vesting in three equal annual instalments commencing on the first anniversary of the date of grant and expiring in five years.

Early warning reporting disclosure

This section is included to satisfy the requirements of National Instrument 62-103 -- The Early Warning System and Related Take-Over Bid and Insider Reporting Issues in respect of the anchor investor.

Immediately prior to the exchange of the subscription receipts, the anchor investor beneficially owned and controlled 71.03 million subscription receipts and, because the subscription receipts did not carry voting rights prior to their exchange, 0 per cent of the issued and outstanding common shares.

Immediately following the exchange of the subscription receipts and the closing of the minority interest acquisition, the anchor investor beneficially owns and controls 71.03 million common shares and 71.03 million warrants, comprising 35,515,000 first warrants and 35,515,000 Second warrants, representing approximately 25 per cent of the issued and outstanding common shares on a non-diluted basis. Assuming the exercise of all warrants beneficially owned and controlled by the anchor investor, the anchor investor would beneficially own and control approximately 38 per cent of the issued and outstanding common shares on a partially diluted basis. The anchor investor acquired the subscription receipts, and the underlying common shares and warrants, for investment purposes and in connection with the strategic partnership described in this news release and the company's prior news releases. In accordance with applicable securities laws, the anchor investor may, from time to time and at any time, acquire additional common shares and/or other equity, debt, or other securities or instruments of the company in the open market or otherwise, and the anchor investor reserves the right to dispose of any or all of its securities in the open market or otherwise at any time and from time to time, and to engage in similar transactions with respect to the securities, the whole depending on market conditions, the business and prospects of the company, and other relevant factors, and subject in each case to the contractual restrictions described above.

An early warning report containing additional information with respect to the foregoing matters will be filed under the company's SEDAR+ profile.

About Tintina Mines Ltd.

Tintina Mines is a TSX-V-listed copper-gold exploration and development company advancing the wholly owned Dos Amigos copper-gold project, formerly the Domeyko sulphuros project, in the Atacama region of Chile through its wholly owned Chilean subsidiary, ABR.

About Sumitomo Corp.

Sumitomo is a leading Fortune Global 500 integrated trading and business investment company headquartered in Tokyo, Japan. Sumitomo's mineral resources business has a long-standing global presence in the copper, non-ferrous metals and battery materials value chains, with interests in a number of large-scale copper mining operations.

About the Gignac family and G Mining Services

The Gignac family are the founders of G Mining Services, a multidisciplinary mining engineering, construction and project development firm founded in 2006 by mining entrepreneur Louis Gignac, recognized for its "self-perform" model and record of delivering mining projects safely, on time and on budget across the Americas, and of G Mining Ventures Corp., a Toronto Stock Exchange-listed gold mining company whose assets include the Tocantinzinho gold mine in Brazil and the Oko West gold project in Guyana.

Qualified person

All scientific and technical information contained in this news release, including in respect of the work program and exploration targets described above, has been reviewed and approved by James Purchase, PGeo, vice president exploration of the company, a qualified person for the purposes of National Instrument 43-101. Mr. Purchase is not independent of the company.

We seek Safe Harbor.