Tintina Mines Completes Strategic Partnership Transaction, Consolidating 100% Ownership of the Dos Amigos (formerly Domeyko Sulfuros) Copper-Gold Project in Chile

C$91 million released from escrow and 100% of the Project consolidated; new Board and management appointed; fully funded ~50,000 metre drilling, feasibility and permitting program launched.

TORONTO, ON / ACCESS Newswire / August 25, 2026 / Tintina Mines Limited (TSXV:TTS) ("Tintina" or the "Company") is pleased to announce the completion of the acquisition and financing transactions first announced on June 2, 2026 (collectively, the "Transactions"). All conditions to the release of the escrowed proceeds of the Company's C$91 million private placement of subscription receipts (the "Subscription Receipts" and the "Offering") 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% minority interest (the "Minority Interest Acquisition") in Andean Belt Resources SpA ("ABR").

Tintina now owns 100% of ABR and, indirectly, 100% of the Dos Amigos Copper-Gold Project (the "Project"), formerly known as the Domeyko Sulfuros Project, together with approximately C$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 August 21, 2026 and in the Company's management information circular dated July 30, 2026, each available under the Company's SEDAR+ profile at www.sedarplus.ca.

Completion Highlights

• Financing completed - gross proceeds of approximately C$91 million released from escrow, of which approximately C$36 million (US$26.25 million) funded the Minority Interest Acquisition and approximately C$55 million is dedicated to advancing the Project toward FID

• 100% ownership consolidated - Tintina now holds 100% of ABR and, indirectly, 100% 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 Corporation and the Gignac family, holds approximately 25% of the issued and outstanding Common Shares on a non-diluted basis

• Board reconstituted - the board of directors of the Company (the "Board") now comprises Mr. Juan Enrique Rassmuss (Chairman), Mr. Mathieu Gignac, Mr. Koji Watanabe, Mr. Stefan Jochum and Mr. Vicente Irarrazaval, following the resignation of Mr. Carmelo Marrelli

• New management appointed - Mr. Claude Dufresne has been appointed Chief Executive Officer and Mr. Chris Stackhouse has been appointed Chief Financial Officer, in each case effective August 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. Koji Watanabe, Mr. Stefan Jochum and Mr. Vicente Irarrazaval

• Work program launched - a fully funded 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 Sulfuros 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 & Directors Commentary

Mr. 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."

Mr. 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 characterisation 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 pre-feasibility 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 & 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 10km-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% owned by Tintina. The mineral resource estimate and PEA referred to below are as set out in Tintina's independent technical report dated February 2, 2026 (the "Technical Report"), prepared in accordance with National Instrument 43-101 - Standards of Disclosure for Mineral Projects ("NI 43-101") and available under Tintina's SEDAR+ profile at www.sedarplus.ca. The Project was previously referred to as the Domeyko Sulfuros 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 mineralisation

• Measured & Indicated Mineral Resources - 100.8 million tonnes 0.35% copper and 0.28 grams per tonne gold

• Inferred Mineral Resources - 256.3 million tonnes 0.34% 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 thousand tonnes of copper and 57 thousand ounces of gold in concentrate

• Life-of-mine total production - approximately 0.9 million tonnes copper and 1.4 million ounces gold

• Exploration upside - 100% ABR-owned Tricolor target, located approximately three kilometers north of the Dos Amigosdeposit, 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 categorised as mineral reserves, and there is no certainty that the results of the PEA will be realised.

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 C$0.80 per Common Share at any time on or before July 9, 2029 (the "First Warrants") and 45,632,646 warrants exercisable at C$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 November 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 C$17 million of Subscription Receipts issued under the Offering, in consideration for which it received a 5% cash finder's fee from the Company.

The securities described in this news release have not been and will not be registered under the United States Securities Act of 1933, as amended (the "U.S. Securities Act"), or any U.S. state securities laws, and may not be offered or sold in the "United States" or to, or for the account or benefit of, U.S. persons, except pursuant to registration under the U.S. Securities Act and applicable U.S. state securities laws or an available exemption from such registration requirements. This news release shall not constitute an offer to sell or the solicitation of an offer to buy any securities in any jurisdiction in which such offer, solicitation or sale would be unlawful.

Incentive Awards Granted

The Board granted an aggregate of 2,857,500 stock options to directors, management and consultants, at an exercise price of C$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 71,030,000 Subscription Receipts and, because the Subscription Receipts did not carry voting rights prior to their exchange, 0% 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 71,030,000 Common Shares and 71,030,000 Warrants, comprised of 35,515,000 First Warrants and 35,515,000 Second Warrants, representing approximately 25% 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% 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 (collectively, the "Securities") 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 at www.sedarplus.ca and may also be obtained by contacting:

Tintina Mines Ltd
Claude Dufresne, P.Eng., Chief Executive Officer
investors@tintinamines.com
+1 (416) 848-0106

About Tintina Mines Limited

Tintina Mines Limited (TSXV:TTS) is a TSXV-listed copper-gold exploration and development company advancing the wholly owned Dos Amigos Copper-Gold Project, formerly the Domeyko Sulfuros Project, in the Atacama Region of Chile through its wholly owned Chilean subsidiary, ABR. For more information, please visit www.tintinamines.com or refer to the Company's filings on SEDAR+ at www.sedarplus.ca.

About Sumitomo Corporation

Sumitomo Corporation 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, recognised for its "self-perform" model and track record of delivering mining projects safely, on time and on budget across the Americas, and of G Mining Ventures Corp., a TSX-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, P.Geo., Vice President Exploration of the Company, a "qualified person" for the purposes of NI 43-101. Mr. Purchase is not independent of the Company.

Cautionary Statement Regarding Forward-Looking Information

This news release contains "forward-looking information" within the meaning of applicable Canadian securities legislation that is based on current expectations, estimates, projections and interpretations about future events as at the date of this news release. Generally, forward-looking information can be identified by the use of forward-looking terminology such as "add" or "additional", "advance", "advancing" or "advancement", "anticipates" or "anticipated", "assumptions", "believes", "can be", "continue" or "continuing", "convert" or "conversion", "deliver" or "delivering", "estimates" or "estimated", "expect", "expected" or "expectations", "forward", "intends" or "intended", "may", "plans", "pending", "potential", "preliminary", "pro forma", "projections", "proposed", "reflects", "subject to", "support", "targeted", "update", "upside", "will" or "will be", "could", "would", "occur", or "achievements".

Forward-looking information in this news release includes, but is not limited to, information with respect to: the anticipated use of the net proceeds of the Offering; the scope, cost, metreage, sequencing, timing and anticipated outcomes of the work program described in this news release, including the resource-conversion, geotechnical, hydrogeological, waste characterisation and condemnation drilling programs; the timing and outcome of an updated mineral resource estimate; the decision to proceed directly to a feasibility study and the timing of the feasibility study; the timing, scope and outcome of the environmental baseline, environmental impact assessment and permitting programs; the evaluation and selection of water supply scenarios for the Project and the timing and outcome of the workstreams supporting the security of the Project's water supply, including the maritime concession and land access, easement and right-of-way arrangements; the timing of a final investment decision and of any subsequent construction and production; the intention to conduct a regional exploration campaign in 2027 and to announce that program in the fourth quarter of 2026; the exploration potential of the Tricolor target and other targets within ABR's land package; the sufficiency of the Company's funding to complete the work program; the potential exercise of the Warrants and the proceeds therefrom; the engagement and performance of G Mining Services; the production, economic, capital and operating cost estimates set out in the Technical Report; and the potential of the Project to become a significant copper operation and a platform for future growth.

Forward-looking information is based on the opinions and estimates of management at the date the information is made, and is based on a number of assumptions and is subject to known and unknown risks, uncertainties and other factors that may cause the actual results, level of activity, performance or achievements of Tintina to be materially different from those expressed or implied by such forward-looking information, including, without limitation: the assumption that drilling and study work will be completed within the metreage, budget and timeframes currently contemplated and will produce results supporting the conversion of Inferred mineral resources to the Indicated category; the assumption that a feasibility study will support a positive final investment decision; the availability of drill rigs, laboratory capacity, contractors and skilled personnel; assay turnaround times; the assumption that the environmental baseline program can be completed across a full seasonal cycle without material interruption and that the environmental impact assessment, the maritime concession and the further sectoral permits required for the Project will be obtained on the timelines contemplated; the risk that permitting timelines are longer than anticipated; the receipt and maintenance of all requisite regulatory approvals; future commodity prices, including copper and gold; changes in foreign exchange and interest rates; actual results of current exploration activities; government regulation; political or economic developments in Chile; community relations and stakeholder engagement; conflicts and their effect on supply chains; environmental risks; pandemic risks; capital and operating cost estimates; operating or technical difficulties in connection with exploration and development activities; employee relations; the speculative nature of copper and gold exploration and development, including the risks of diminishing quantities or grades of reserves; contests or uncertainties over title to properties; tax considerations and changes in tax law or the interpretation thereof; changes in project parameters as plans continue to be refined; as well as those risk factors discussed in Tintina's management's discussion and analysis and other continuous disclosure filings under its profile on SEDAR+ at www.sedarplus.ca. Tintina cautions that the foregoing list of material factors and assumptions is not exhaustive. Although Tintina has attempted to identify important factors that could cause actual results to differ materially from those contained in forward-looking information, there may be other factors that cause results not to be as anticipated, estimated or intended. Accordingly, readers should not place undue reliance on forward-looking information. Tintina does not undertake to update any forward-looking information, except in accordance with applicable securities laws.

Cautionary Note Regarding Mineral Resources

Until mineral deposits are actually mined and processed, mineral resources must be considered as estimates only. Mineral resource estimates are not mineral reserves and do not have demonstrated economic viability. The estimation of mineral resources is inherently uncertain, involves subjective judgement about many relevant factors and may be materially affected by, among other things, environmental, permitting, legal, title, taxation, socio-political, marketing or other relevant risks, uncertainties, contingencies and other factors described in Tintina's public disclosure available under its profile on SEDAR+ at www.sedarplus.ca. The quantity and grade of reported "Inferred" mineral resource estimates are uncertain in nature and there has been insufficient exploration to define such "Inferred" mineral resource estimates as an "Indicated" or "Measured" mineral resource, and it is uncertain if further exploration will result in upgrading "Inferred" mineral resource estimates to an "Indicated" or "Measured" mineral resource. It cannot be assumed that all or any part of an "Inferred" or "Indicated" mineral resource estimate will ever be upgraded to a higher category. The mineral resource estimates disclosed in this news release were reported using the Canadian Institute of Mining, Metallurgy and Petroleum Definition Standards for Mineral Resources and Mineral Reserves in accordance with NI 43-101. The PEA is preliminary in nature and includes Inferred mineral resources that are considered too speculative geologically to have the economic considerations applied to them that would enable them to be categorised as mineral reserves. There is no certainty that the economic results described in the Technical Report will be realised.

For Further Information

Tintina Mines Limited
Claude Dufresne, P.Eng., Chief Executive Officer
investors@tintinamines.com
+1 (416) 848-0106

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

SOURCE: Tintina Mines Limited

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