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Vancouver, British Columbia--(Newsfile Corp. - September 28, 2026) - Sierra Madre Gold and Silver Ltd. (TSXV: SM) (OTCQX: SMDRF) ("Sierra Madre" or the "Company") is pleased to provide an operational update on activities at its Guitarra silver-gold mine complex in Estado de Mexico, Mexico.

Throughput at the Guitarra processing plant has significantly increased following Phase 1 expansion modifications to the existing crushing and milling circuits. Daily production has reached up to a steady 720 tonnes per day ("tpd"). This represents more than a 40% increase versus the previous nameplate capacity of 500 tpd. Further modifications to increase capacity are scheduled to be made following the commissioning of the new 11x12 ball mill.

Greg Liller, Chief Operating Officer and Executive Chairman, commented, "We continue to advance our Phase 1 and Phase 2 expansions at Guitarra. With the new ball mill now installed, Sierra Madre has also accelerated underground development. We have started groundworks for the permitted dry stack tailings facility expansion, a key component of our Phase 2 plan to increase throughputs to 1,200 tpd to 1,500 tpd. We look forward to updating the market as we advance towards Phase 2 expansion."

Foundation construction and installation of the 11x12 ball mill has been completed. The foundation and cement base required the pouring of 400 cubic meters of cement along with 16 tonnes of steel rebar.

Figure 1: New Ball Mill Installed

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Installation of the drive motor, cyclones and instrumentation is under way with commissioning expected in November 2026. This ball mill, combined with the existing ones, is expected to achieve the Phase 2 goal of 1200 tpd to 1500 tpd of milling capacity, more than eight months ahead of schedule.

Coloso and Nazareno Development

Development has been accelerated at all three of the mines within La Guitarra - Guitarra, Nazareno and Coloso - to provide feed to the expanded plant. Approximately 2.6 kilometers of development drives have been completed since June 2026. As haulage ramps are being driven both vertically and downward from the 180-access level, this ramp development is expected to allow for additional production areas to be developed. Since July 2026, over 800 meters of access and production drives have been completed. Based on the 2023 Mineral Resource Estimate, the Nazareno Measured resource stood at 309,877 tonnes grading 215 g/t silver and 0.55 g/t gold, for 257 g/t AgEq. Inferred resources are at 753,784 tonnes grading 229.2 g/t silver, 0.29 g/t gold for 251 g/t AgEq(1). AgEq calculated at a 77.27:1 silver gold ratio. Reconciliation from actual stope mining to date has shown higher gold grades.

Guitarra Development

At the Guitarra mine, over 1.5 kilometres of development has been completed since June 2026. Work in the lower Central mine area has been accelerated and this area now contributes an important portion of mill feed. Development work needed to bring the Los Angeles bulk tonnage deposit into production has been started. The new design is expected to allow easier access and haulage alongside a lower mining cost in the future. The development and dewatering of the San Raphael I and II areas has been accelerated with the purchase of additional pumps. The current mine plan calls for initial production from higher-grade blocks by the end of October 2026.

East District Development

The company is also examining the possibility of bringing a small portion of the East District into production. At Santa Ana, an initial mine design has been completed and the Company is contemplating beginning construction of a portal in 2027. The Santa Ana mineralization is wide and mining is planned using long hole methods. The 2023 resource estimate for the Santa Ana deposit stands at 761,292 tonnes in the Measured category, grading 159 g/t silver and 0.19 g/t gold, or 174 g/t AgEq. The Inferred resource is 544,892 tonnes grading 178 g/t silver, 0.13 g/t gold and an AgEq grade of 188 g/t(1). AgEq calculated at a 77.27:1 silver gold ratio.

Dry Stack Tailings Facility

Ground work for the fully permitted Phase 4 tailings expansion has begun. Per SEMERNAT (Secretaría del Medio Ambiente y Recursos Naturales, the federal Mexican regulatory agency in charge of environmental permitting) requirements, trees have been measured and marked for cutting and the required paperwork submitted. Clearing of trees and vegetation is scheduled for October. Bid documents for earthworks have been prepared and sent out with mobilization of the chosen contractor scheduled for November 2026. The first construction phase consists of three parts with a capacity of 877,000 tonnes. Total capacity within the permitted area is on the order of over 5,000,000 tonnes.

(1) Notes for 2023 La Guitarra Mineral Resource Estimate: Canadian Institute of Mining Metallurgy and Petroleum ("CIM") definition standards were followed for the resource estimate. The 2023 resource models used nominal cutoff grades which are based on mining and milling costs of US$50 for cut and fill mining, US$38 per tonne for long-hole. A net payable recovery of 70% (historical plant recovery plus an allowance for smelter deductions, refining costs, and concentrate transportation). Silver price of US$22 and a gold price of $1700 and a Gold Silver Ration of 77.27:1. Assays were capped at 825 g/t for silver and 6.55 g/t for gold. Variable cut-off by deposit: Nazareno and Coloso - Block Model 135 AgEq cut-off grade (COG) and a 1 m Minimum True Thickness; Guitarra - Polygonals Estimates 135 g/t AgEq COG and a 1 m Minimum Horizontal Width; Los Angeles - Block Model Long Hole Mining 90 g/t AgEq COG; Mina De Agua - East District Polygonal Estimate 135 g/t AgEq COG or 90 g/t AgEq COG and > 2 m Horizontal Width; The tailings used a 30 g/t AgEq COG. Mineral Resources that are not mineral reserves do not have economic viability. Numbers may not add due to rounding. The estimate of mineral resources may be materially affected by: metal prices and exchange rate assumptions; changes in local interpretations of mineralization geometry and continuity; changes to grade capping, density and domain assignments; changes to geotechnical, mining and metallurgical recovery assumptions; ability to maintain environmental and other regulatory permits and ability to maintain the social license to operate. A copy of the 2023 NI 43-101 report, prepared by TechSer Mining Consultants Ltd. ("TechSer") of Vancouver B.C., by David Thomas, P.Geo. and QP Geology and Cristian Garcia, P.Eng. and QP Mining, titled "La Guitarra Mineral Resource Estimate Guitarra Silver-Gold Project, Temascaltepec, Estado de México, México" with an effective date of October 24, 2023, is available on SEDAR+ and the company's website at https://sierramadregoldandsilver.com/presentations/NI-43-101-La-Guitarra-Mineral-Resource-Estimate.pdf

Qualified Person

Mr. Gregory Smith, P. Geo, Director of Sierra Madre, is a Qualified Person as defined by NI 43-101, and has reviewed and approved the technical data and information contained in this news release. Mr. Smith has verified the technical and scientific data disclosed herein.

About Sierra Madre

Sierra Madre Gold and Silver Ltd. (TSXV: SM) (OTCQX: SMDRF) is a precious metals producer and exploration company focused on the operation, exploration, and development at its Guitarra mine complex in the Temascaltepec mining district, Mexico. The Guitarra mine is a permitted underground mine, which includes a 500 tpd processing facility that operated until mid-2018 and restarted commercial production in January 2025.

In June 2026, Sierra Madre closed the acquisition of the Del Toro silver mine, adding a past-producing, fully permitted asset to its Mexico-focused silver and gold portfolio.

The Company also holds the +2,600 ha Tepic Project, which hosts low-sulphidation epithermal gold and silver mineralization with an existing historic resource.

Sierra Madre's management team has played key roles in managing the exploration and development of silver and gold mineral reserves and mineral resources. Sierra Madre's team of professionals has collectively raised over $1 billion for mining companies.

On behalf of the board of directors of Sierra Madre Gold and Silver Ltd.,

"Alexander Langer"
Alexander Langer
President, Chief Executive Officer and Director
778-820-1189

Cautionary Note Regarding Production Decisions

The Company's decision to place the mine into commercial production, expand a mine, make other production related decisions, or otherwise carry out mining and processing operations, is largely based on internal non-public Company data and reports from previous operations and the results of test mining and processing. The Company is not basing any production decisions on NI 43-101 compliant reserve estimates, preliminary economic assessments or feasibility studies and, as a result, there is greater risk and uncertainty as to future economic results from the Guitarra Mine Complex, including 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, and a higher technical risk of failure than would be the case if a feasibility study were completed and relied upon to make a production decision.

Cautionary Note Regarding Forward-Looking Information

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.

This press release contains "forward-looking information" and "forward-looking statements" within the meaning of applicable securities legislation. The forward-looking statements herein are made as of the date of this press release only, and the Company does not assume any obligation to update or revise them to reflect new information, estimates or opinions, future events or results or otherwise, except as required by applicable law. Often, but not always, forward-looking statements can be identified by the use of words such as "plans", "expects", "is expected", "budgets", "scheduled", "estimates", "forecasts", "predicts", "projects", "intends", "targets", "aims", "anticipates" or "believes" or variations (including negative variations) of such words and phrases or may be identified by statements to the effect that certain actions "may", "could", "should", "would", "might" or "will" be taken, occur or be achieved. Forward-looking statements include, without limitation, statements regarding discussions of future plans, including the expected timing of concentrate shipments; the Company increasing production; the Company receiving revenues on a weekly basis and such revenues allowing the Company to comfortably expand to without further capital needs; production and the expected timing and production levels thereof.

The forward-looking statements involve numerous risks and uncertainties, and actual results might differ materially from results suggested in any forward-looking statements. These risks and uncertainties include, among other things, that predicted production levels will be achieved and that existing production levels will be maintained.

In making the forward-looking statements in this news release, the Company has applied certain material assumptions, including without limitation, that the Company will be able to execute its future plans as intended, that predicted production levels will be achieved and that existing production levels will be maintained.

Although management of the Company has attempted identify important factors that could cause actual results to differ materially from those contained in forward-looking statements or forward-looking information, there may be other factors that cause results not to be as anticipated, estimated or intended. There can be no assurance that such statements will prove to be accurate, as actual results and future events could differ materially from those anticipated in such statements. Accordingly, readers should not place undue reliance on forward-looking statements and forward-looking information. Readers are cautioned that reliance on such information may not be appropriate for other purposes.

SOURCE: Sierra Madre Gold and Silver Ltd.

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