GR Silver Mining Announces Resumption of Plomosas Silver Project Field Work

VANCOUVER, May 20, 2025 - GR Silver Mining Ltd. ("GR Silver Mining" or the "Company") (TSXV: GRSL) (OTCQB: GRSLF) (FRANKFURT: GPE) - is pleased to announce the resumption of field work including drilling on the Plomosas Silver Project in Sinaloa, Mexico. Although there had been no incidents of violence on the Company's properties and no threats to the Company or its employees or consultants in accessing our Project, management had decided to temporarily pause field work (news release, April 29, 2025) to allow time for the considerable efforts of the Government of Mexico to increase security and stability in the project region.

President and Chief Operating Officer, Márcio Fonseca, noted, "The security situation in the project region appears to have stabilized based on our observations on site and in extensive discussions with members of our community and various levels of Government. We are grateful to these stakeholders for their efforts to improve conditions. Our highly experienced in-country team has expressed confidence in the current situation and their ability to safely return to active field exploration. We are very excited to resume sampling and drilling the prospective targets we have outlined. The exploration team has returned to activities on site prioritizing surface investigations, prior to conducting step out drilling of high-grade silver results returned from some previous trench sampling in the NW and SE Extensions of the current NI 43-101 resource."

Previous surface exploratory trench results include:

• NW Extension - 56 m at 196 g/t Ag, including 15 m at 472 g/t Ag, (news release, February 21, 2019).
• New Hydrothermal Breccias (Subparallel Breccias), 12 m at 323 g/t Ag within a broader zone of 24 m at 219 g/t Ag, including high-grade Ag up to 1 m at 974 g/t Ag, (news release, May 22, 2019).

Management believes that these previous results provide further encouragement for potential expansion of the resource with planned step out drilling.

On March 3 (news release), the Company announced the commencement of a step-out drilling program aiming to expand the San Marcial mineralization footprint by as much as 350 meters northwest from the current NI 43-101 resource area, as well as test potential new parallel zones located immediately to the southeast of the current NI 43-101 resource area. The Company has completed surface evaluation along 500 meters of strike length, focused on a prospective geological contact with evidence of silver mineralization and seeking blind targets highlighted in Figure 1. Initial field results indicate new prospective drilling targets along this potential mineralization footprint extension.

Noting that the safety of our employees, consultants, suppliers, and community members remains paramount, management considers it prudent to resume this program while vigilantly monitoring the situation.

Management continues its assessment of and potential implementation of a Bulk Sampling Test Mining program at the permitted former Plomosas Mine, similar to the previously announced successful program completed at the historical San Juan Mine, benefiting from existing permits and infrastructure on site, and explore opportunities to achieve critical mass in the Mexican silver mining industry.

About GR Silver Mining Ltd.
GR Silver Mining is a Canadian-based, Mexico-focused junior mineral exploration company engaged in cost effective silver-gold resource expansion on its 100%-owned assets, located on the eastern edge of the Rosario Mining District, in the southeast of Sinaloa State, Mexico. GR Silver Mining controls 100% 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 km² of highly prospective advanced stage exploration concessions, position the Company well in the pursuit for resource expansion at the Plomosas Project.

GR Silver Mining Ltd.
Eric Zaunscherb, Chair & CEO

Cautionary Statement Regarding Forward-Looking Information
This press release contains "forward-looking statements" within the meaning of applicable Canadian securities legislation and information that are based on the beliefs of management and reflect the Company's current expectations. When used in this press release, the words "estimate", "project", "belief", "anticipate", "intend", "expect", "plan", "predict", "may" or "should" and the negative of these words or such variations thereon or comparable terminology are intended to identify forward-looking statements and information. Such statements and information reflect the current view of the Company. Risks and uncertainties may cause actual results to differ materially from those contemplated in those forward-looking statements and information. By their nature, forward-looking statements involve known and unknown risks, uncertainties and other factors which may cause our actual results, performance or achievements, or other future events, to be materially different from any future results, performance or achievements expressed or implied by such forward-looking statements.

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 press release.

SOURCE GR Silver Mining Ltd.