Mr. Marcio Fonseca reports

GR SILVER MINING RECEIVES A 5-YEAR MILESTONE DRILL PERMIT FOR THE SAN MARCIAL AREA OF THE PLOMOSAS SILVER PROJECT

GR Silver Mining Ltd. has received a key five-year drill permit for the San Marcial area authorizing additional stepout and exploration drilling in an extensive area surrounding the current National Instrument 43-101 resource area. The five-year informe preventivo (IP) issued by the Secretaria de Medio Ambiente y Recursos Naturales (Semarnat) of Mexico will allow for the drilling of stepout and exploration holes at 46 new drill sites in the San Marcial area.

The IP does not limit the total metreage or number of drill holes that can be drilled in the 46 newly approved drill sites. This provides the company with flexibility for multiple drill hole orientations within the three defined target areas as well as the ability to explore new targets along the edges of the chargeability geophysical anomaly.

This is the first time that the company has been granted such a long-term drill permit, which bodes well for its initiatives to expand known mineralization and support resource growth, in addition to exploring the recently discovered silver-rich epithermal system sitting on the edge of a regional-scale porphyry-intrusive-related geological setting. Receipt of the drill permit is also evidence that GR Silver Mining's persistent and patient efforts as well as constructive engagement with Mexican authorities have been effective in successfully advancing the Plomosas silver project.

The receipt of the permit allows the company to proceed with the following activities in the coming months:

• Complete the final three drill holes of the 2025 summer drilling program as outlined in the Sept. 3, 2025, press release; upon completion and receipt of all assays, incorporate all drilling data into the 3-D model, including recent discoveries such as SMS25-09 (75 metres at 293 grams per tonne silver equivalent); this will guide the planning of future stepout drilling in the San Marcial area;
• Conduct additional geophysical investigations, including potential downhole geophysical surveys in key drill holes within the resource area; these surveys will assist in modelling and targeting high-grade silver mineralized hydrothermal breccias beneath the existing resource area; modern downhole geophysics will serve as an alternative to support directional drilling, increasing the likelihood of intersecting the epithermal system down dip from the resource area boundaries;
• After completion of the above activities, the company will proceed with further steps in the negotiations with third party drilling companies for follow-up drilling programs at the San Marcial area;
• Advance additional drilling under the new drill permit, using the updated 3-D model and geophysical surveys scheduled for the summer of 2025 and continuing throughout the rest of the year.

The drilling results in the summer 2025 drilling phase have expanded the San Marcial mineralized footprint, extending high-grade mineralization a further 100 metres below the previous resource outline. Within these broad zones of silver-dominant, high-grade mineralization, a transition with depth has been observed, marked by changes in alteration and lithology, which supports the company's interpretation of a robust epithermal system hosted along the northern margin of a large regional-scale porphyry intrusive complex. These results validate the company's exploration model and highlight the significant potential for future resource growth.

Qualified person

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

About the Plomosas project

The Plomosas project, including the recent high-grade silver discovery in the San Marcial SE area, is progressing in 2025 as an emerging high-grade silver district located in southwestern edge of the Sierra Madre Occidental in Sinaloa, Mexico. The Plomosas project, covering 7,823 hectares, 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 2025, 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.

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, in the southeast of Sinaloa state, 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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