Mr. Marcio Fonseca reports

GR SILVER MINING COMMENCES 20,000 M STEP-OUT DRILLING CAMPAIGN AT SAN MARCIAL ACCELERATING THE 2026 RESOURCE EXPANSION PROGRAM

GR Silver Mining Ltd. has mobilized multiple drill rigs to the San Marcial area of its wholly owned Plomosas silver project to commence the previously announced 20,000-metre stepout drilling program.

Highlights:

• 20,000-metre stepout drill program under way at San Marcial;
• Multiple rigs mobilizing to site, two on site and additional drill rigs on the way;
• Stepout drilling program targeting resource expansion after successful 2025 drill campaign;
• Mineral resource update and preliminary economic assessment planned for late 2026;
• The exploration office has been relocated to Durango, with access to the Plomosas project now managed from Durango State; this relocation addresses recent operational challenges in Sinaloa while ensuring the continuation of high operational standards at the Plomosas project.

This strategic drilling program, focused on expanding silver resources, builds on the success of the 2025 drilling campaign, which returned wide, high-grade intersections, including SMS25-09 (75 metres at 260 grams per tonne silver). The stepout drilling program is expected to be completed early in the second half of 2026 and will support an updated mineral resource estimate for the Plomosas silver project. Data collected will also be integrated into a preliminary economic assessment by the end of 2026.

The program leverages the recently granted five-year surface drilling permit and will deploy multiple drill rigs on several surface sites to test extensions along strike and downplunge beyond the current limits of known silver mineralization. The commencement of drilling followed a detailed review of regional and site-specific conditions, along with the implementation of a comprehensive logistical and monitoring strategy to ensure the efficient performance and successful completion of the program at the Plomosas silver project with access from Durango, Mexico.

Marcio Fonseca, president and chief executive officer, commented: "Two thousand twenty-six is expected to be a pivotal year for GR Silver Mining as the company leverages the five-year drilling permit obtained last year, together with its strong financial position, to advance resource growth at San Marcial. Regional and site-specific conditions at active work areas are continuously monitored, and, over the past six months, the company has implemented additional protocols and mitigation measures to further manage safety risks associated with operating in Mexico. To enhance operational efficiency and mitigate risks related to current security conditions in Sinaloa, the company has relocated its exploration office to Durango, located conveniently to ready access the Plomosas silver project. This strategic move initiated in late 2025 supports the 2026 drilling and bulk-sampling test mining programs and enables effective performance of field activities. Our engagement with local authorities continues given their past, present and expected future support of the project."

Key stepout drilling campaign objectives

The company plans to substantially increase total drilling in the San Marcial area in 2026 by completing an additional 20,000 metres of surface drilling. This program represents an increase of 100 per cent in metres drilled outside the National Instrument 43-101 resource area and will consist predominantly of stepout drill holes. The program also includes drilling of the recently discovered parallel breccia zone.

Completion of a revised geological model, integrating 2025 drilling results into the existing 3-D model, has enabled the exploration team to better define the controls on silver mineralization associated with major geological structures and host rocks in the San Marcial area.

The stepout drilling program has the following primary objectives:

• Expand the footprint of the silver-mineralized system, hosted in a chlorite-rich hydrothermal breccia, by an additional 200 metres along strike;
• Define the boundaries of silver mineralization to shallow depths of up to 400 metres below surface;
• Complete an initial stepout drilling program at an anticipated drill hole spacing of 70 metres, supported by existing wide intersections proximal to the stepout areas;
• Grow mineral resources by adding silver ounces within zones characterized by high-grade silver primary content;
• Expand the footprint along strike and downdip of the recently discovered parallel breccia, where previous intersections such as SMS 25-10A (nine metres at 374 grams per tonne silver and an associated gold discovery of one metre at 32.1 grams per tonne gold) have outlined areas with strong potential for resource growth;
• Delineate shallow, high-grade silver mineralization to support an updated mineral resource estimate and subsequent integration into a preliminary economic assessment.

About the Plomosas project

The Plomosas project, including the recent high-grade silver discovery in the San Marcial SE area, is progressing in 2026 as an emerging high-grade silver district located on the southwestern edge of the Sierra Madre Occidental, at the boarder of Durango and Sinaloa, Mexico. The Plomosas project, covering 7,823 hectares and including the historical Plomosas underground mine, benefits from mine infrastructure, road access and existing permits associated with past-producing mining sites. The district contains intermediate-to-low-sulphidation epithermal silver and gold mineralization, hosted in hydrothermal breccias and veins. Recent success in exploration and drilling has delineated wide, high-grade, shallow hydrothermal breccias in the San Marcial area, including the SE area discovery, where stepout drilling is under way in 2026, aiming for continuous resource growth. At the historical Plomosas mine, where Grupo Mexico operated the underground mine from 1985 to 2000, exploration, underground sampling and metallurgical programs are being conducted to support future decisions regarding the implementation of a bulk-sampling test mining program.

Quality assurance/quality control procedures

The company has implemented QA/QC procedures, which include the insertion of blank, duplicate and standard samples in all sample lots sent to SGS de Mexico SA de CV laboratory facilities in Durango, Mexico, for sample preparation and assaying. For every sample with results above silver greater than 100 parts per million (over the limit), these samples are reassayed by SGS de Mexico. Core samples are represented by both HQ and NQ diameters and samples are represented by one-half core split of original core. The analytical methods include four-acid digestion and inductively coupled plasma optical emission spectrometry, with lead fusion fire assay and a gravimetric finish for silver above overlimits. For gold assays, the analytical methods are lead fusion and atomic absorption spectrometry, lead fusion fire assay, and gravimetric finish for gold above overlimits (greater than 10 parts per million).

Qualified person

The qualified person under National Instrument 43-101, Standards of Disclosure for Mineral Projects, for this news release is Marcio Fonseca, PGeo, president and chief executive officer of GR Silver Mining, who has reviewed and approved its contents.

About GR Silver Mining Ltd.

GR Silver Mining is a Canadian-based, Mexico-focused mineral exploration company engaged in cost-effective silver-gold resource expansion on its 100-per-cent-owned assets, located on the eastern edge of the Rosario mining district, at the border of Durango and Sinaloa states in Mexico. GR Silver Mining controls 100 per cent of the Plomosas project, including the former Plomosas underground mine and wide, high-grade silver mineralized zones at the San Marcial area. Recent discoveries in the 78 square kilometres of highly prospective, advanced-stage exploration concessions position the company well for resource expansion at the Plomosas project.

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