Minera Alamos Provides Update on Development Plans for Copperstone Mine

Toronto, Ontario--(Newsfile Corp. - June 4, 2025) - Minera Alamos Inc. (TSXV: MAI) (OTCQX: MAIFF) ("Minera Alamos" or the "Company") is pleased to announce that the Mine Plan of Operations ("MPO") amendment for the Copperstone Mine gold project ("Copperstone Mine" or the "Project") has been submitted in final form to satisfy the requirements of the United States Code of Federal Regulations Title 43 Subpart 3809 ("Code of Federal Regulations"), administered by the U.S. Bureau of Land Management ("BLM").

Highlights:

• All key permits have been received with exception of minor amendments which are due to a slight change in processing technology.

• The final amendment to the project's MPO is expected to be received prior to YE-2025 which allows full re-start of the Copperstone Mine.

• Under the authorization from the existing site permits, site development activities can be initiated in parallel with the pending MPO amendment in order to "fast-track" the project restart.

• A reissued Preliminary Economic Assessment (PEA) in February 2025 demonstrates robust project economics, with an after-tax Net Present Value (NPV) of US$66 million at a gold price of US$1,800/oz and US$200 million at US$2,800/oz. The after-tax Internal Rate of Return (IRR) ranges from 53.6% to 152.7% across these scenarios.

• Final planning is underway for the transfer of existing process plant equipment currently owned by Minera Alamos to the Copperstone site so the work can begin for its refurbishment and installation.

• The Company is reviewing exploration programs previously planned for the site which included up to 15,000 meters of drilling to test 8 existing targets with the potential to demonstrate the significant upside of the asset. Final decisions on the scheduling of exploration efforts will be made to best coincide with production restart activities at the site.

• Engineering activities have been ramped up to optimize plans for the mine restart and process plant installation. An updated technical study for the project will be released in Q4 2025 to demonstrate the positive impact of these efforts.

• Project finance discussions continue with a number of interested parties that have provided indicative term sheets. The Company is evaluating all options to support the development restart.

Darren Koningen, CEO of Minera Alamos commented: "The submission of the final amendment for the Copperstone Gold Mine existing Plan of Operations is a significant step towards meeting our timelines for the restart of operations. The decision to amend the existing Plan of Operations was taken as a result of extensive engineering evaluations demonstrating that the use of a combination of previous processing paths provided a superior economic return for the mine while maximizing operating flexibility for the future. While focusing on optimizing mine plans for greater efficiency and ensuring that our process plant can accommodate future growth, we are also excited to start working to expand the overall resource potential through targeted drilling. By leveraging used equipment and re-evaluating marginal material under current economics, we will continue to work to reduce costs and enhance long-term value for the project."

Permitting

The final version of the Mine Plan of Operations ("MPO") amendment for the Copperstone Mine ("Copperstone Mine" or the "Project") has been submitted to meet the requirements of Title 43, Subpart 3809 of the United States Code of Federal Regulations, as administered by the U.S. Bureau of Land Management ("BLM"). This application represents the primary permitting milestone for a restart of operations at the site and is expected to be received prior to YE-2025. While awaiting its receipt, a number of other minor amendments to other existing site permits are also being prepared. This includes:

• An update to Aquifer Protection Permit (APP) which is expected to be submitted shortly, followed by an amendment to Air Quality Control Permit under the Title V Class I air quality permit program.

• A minor revision to the reclamation plan, reflecting modest changes to the process plant infrastructure, is anticipated to be completed in the second half of the year, with final approval of the closure plan expected by the third quarter of 2025.

By the fourth quarter of 2025, the Copperstone Mine is expected to have secured all required permits amendments to support a planned restart of gold mining operations in 2026.

Engineering and Development Activities

Management has identified several opportunities to enhance the value of the Copperstone Project that will be evaluated during the current development phase. The Company is considering various engineering, procurement, construction, and management approaches, including hybrid models that maximize the use of internal expertise to ensure an efficient and cost effective transition from development to mining operations. Additional opportunities include:

• Expand Resources - Priority targets include additional drilling along the down-dip plunge of the C and D zones within the main Copperstone shear, the South Zone, and the Footwall Zone. Another focus will be follow-up drilling between the A and B zones, where previous drilling encountered high-grade gold mineralization that has not been fully delineated.

• Mining - Evaluate whether previously marginal-grade material can be included in the updated mine plan under current economic conditions and if access costs are minimized by pre-developed stopes. Additional efforts will focus on optimizing mine design, including access points, ventilation raises, and adjustments to stope height and width.

• Process Plant - Assess opportunities to ensure excess capacity exists within the new plant facilities so that future increases in plant throughput are possible in line with higher mining rates and potential resource expansion. Additional metallurgical studies are to be completed to maximize process flexibility assuming additional resource zones will ultimately be added to the mine plan.

• Used Equipment - Finalize engineering details in order to maximize the use of used equipment to reduce capital costs and lead times, including equipment already owned by the Company.

Exploration Activities

Note: all information and diagrams in this release are historic in nature and originate from the data files of prior property holders. A Qualified Person has not at this time completed work to determine if the historic results and diagrams in this section are compliant with NI 43-101. While the Company considers the results to be of relevance to the Copperstone project, readers are advised that the information is historic in nature and should not be relied upon. Drill hole assay intervals are downhole intervals and are not 'true widths' as there is insufficient data to determine true widths at this time.

An initial four opportunities have already been identified to enhance the value of the Copperstone Project via exploration and will be further evaluated during the construction phase (Figure 1).

• Drill test for the presence of the footwall zone gold mineralization at depth and under the D zone. See Figure 1-"A"

• Historic drill hole CS-266 intersepted gold mineralization (3.4 grams/tonne over 3.0 metres) approximately 200 meters southwest of the historic Copperstone pit and represents a potential parallel gold discovery that remains completely untested. See Figure 1 - "B"

• Drilling is planned to define and expand the southwest zone located 760 meters southwest of the historic Copperstone pit. See Figure 1 -"C"

• Drilling is planned for the area proximal to historic drill hole 06CS-20 which intersected gold mineralization (20.5 grams/tonne over 1.5 metres), approximately 900m southwest of the Copperstone pit and has been neither been followed up on nor has there been any drilling within 150m of the drill hole. See Figure 1-'D"

Figure 1. Copperstone Mine Long section looking north

Table 1. Copperstone Footwall Zone - Significant Intercepts

The four exploration opportunities described above are located close to the current resources and form part of the known mineralization hosted by the footwall of the low angle Copperstone Fault, which is the host of the current resource. The most significant intercept was recorded in drill hole CRD-03-10, which returned 5 feet grading 47 g/t. The grades observed and shown in Table 1 support further exploration drilling to potentially upgrade the mineralization so that it can be incorporated into future mine plane (note that mineralization located in the footwall zone is not included in the current resource estimate).

PEA Cautionary Note:

Readers are cautioned that the PEA is preliminary in nature and includes inferred resources that are considered too speculative to have the economic considerations applied to them that would enable them to be categorized as mineral reserves. There is no certainty that the PEA results will be realized. Mineral resources are not mineral reserves and do not have demonstrated economic viability. Additional work is needed to upgrade these mineral resources to mineral reserves.

Minera Alamos Financials (Q1-2025)

The Q1-2025 Financial Statements and MD&A for the Company were filed to SEDAR on May 30, 2025. The major operational differences between these statements and those filed for YE-2024 (April 30, 2025) relate primarily to the completion of the acquisition of Sabre Gold Mines Corp. on February 6, 2025.

• Total consideration of $26,407,419 which includes the issuance of 76,499,114 common shares of the Company
• Upon closing of the acquisition the Company recorded $30,474,816 of mineral property costs as expenses to meet the Company's policy to expense all pre-development costs as exploration expenses
• Additional transaction related costs accumulated during the closing period.

Readers are encouraged to review the filed statements and MD&A for a full description of details related to the transaction.

About Minera Alamos

Minera Alamos is a gold production and development Company. The Company has a portfolio of high- quality Mexican assets, including the 100%-owned Santana open-pit heap-leach mine in Sonora that is

currently going through the start-up of operations at the new Nicho Main deposit. The 100%-owned Cerro de Oro oxide gold project in northern Zacatecas has considerable past drilling and metallurgical work completed and the proposed mining project is currently being guided through the permitting process by the Company's permitting consultants. The La Fortuna open pit gold project in Durango (100%-owned) has a positive, robust preliminary economic assessment (PEA) completed, and the main Federal permits are in place. Minera Alamos is built around its operating team that together brought three open pit heap leach gold mines into successful production in Mexico over the last 14 years. Minera Alamos also wholly- owns the Copperstone gold mine and associated infrastructure in La Paz Country, Arizona, an advanced development asset with a permitted plan of operations that can be developed in parallel with planned project advancements in Mexico.

The Company's strategy is to develop very low capex assets while expanding the projects' resources and

continuing to pursue complementary strategic acquisitions.

Mr. Darren Koningen, P. Eng., Minera Alamos' CEO, is the Qualified Person responsible for the technical content of this press release under National Instrument 43-101.

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Caution Regarding Forward-Looking Statements

This news release may contain forward-looking information and Minera Alamos cautions readers that forward-looking information is based on certain assumptions and risk factors that could cause actual results to differ materially from the expectations of Minera Alamos included in this news release. This news release includes certain "forward-looking statements", which often, but not always, can be identified by the use of words such as "believes", "anticipates", "expects", "estimates", "may", "could", "would", "will", or "plan". These statements are based on information currently available to Minera Alamos and Minera Alamos provides no assurance that actual results will meet management's expectations. Forward-looking statements include estimates and statements with respect to Minera Alamos' future plans with respect to the Projects, objectives or goals, to the effect that Minera Alamos or management expects a stated condition or result to occur and the expected timing for release of a resource and reserve estimate on the projects. Since forward-looking statements are based on assumptions and address future events and conditions, by their very nature they involve inherent risks and uncertainties. Actual results relating to, among other things, results of exploration, the economics of processing methods, project development, reclamation and capital costs of Minera Alamos' mineral properties, the ability to complete a preliminary economic assessment which supports the technical and economic viability of mineral production could differ materially from those currently anticipated in such statements for many reasons. Minera Alamos' financial condition and prospects could differ materially from those currently anticipated in such statements for many reasons such as: an inability to finance and/or complete an updated resource and reserve estimate and a preliminary economic assessment which supports the technical and economic viability of mineral production; changes in general economic conditions and conditions in the financial markets; changes in demand and prices for minerals; litigation, legislative, environmental and other judicial, regulatory, political and competitive developments; technological and operational difficulties encountered in connection with Minera Alamos' activities; and other matters discussed in this news release and in filings made with securities regulators. This list is not exhaustive of the factors that may affect any of Minera Alamos' forward-looking statements. These and other factors should be considered carefully and readers should not place undue reliance on Minera Alamos' forward-looking statements. The Company does not undertake to update any forward-looking statement that may be made from time to time by the Company or on its behalf, except in accordance with applicable securities laws.

The Company does not have a feasibility study of mineral reserves, demonstrating economic and technical viability for the Santana project, and, as a result, there may be an increased uncertainty of achieving any particular level of recovery of minerals or the cost of such recovery, including increased risks associated with developing a commercially mineable deposit. Historically, such projects have a much higher risk of economic and technical failure. Failure to commence production would have a material adverse impact on the Company's ability to generate revenue and cash flow to fund operations.

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