GR Silver Mining Delivers Positive Progress on Phase II Underground Sampling at Plomosas Mine

On October 15, 2025, GR Silver Mining announced positive progress on its Phase II underground sampling program at the historic Plomosas Mine. The company reported high-grade channel sample results, including 6.7 meters of 1,040 g/t silver equivalent (AgEq) and 4.2 meters of 1,018 g/t AgEq. The two-phase sampling program is now complete and was designed to support a future Bulk Sample Test Mining Program (BSTM), which the company is now targeting for commencement in early 2026. The company is also considering the construction of an on-site pilot processing plant.

Concurrently, the company announced the resignation of Mr. Alejandro Cano, Vice President of Operations, and the appointment of CFO Mr. Robert Payment to the additional role of Corporate Secretary, following the retirement of Mr. Blaine Bailey.

The news is a routine, positive step forward in de-risking the Plomosas Mine portion of the company's flagship project. The high-grade sampling results are encouraging and confirm the potential for remnant mineralization within the historic mine, which aligns with initial results reported on July 8, 2025. This successfully concludes a key prerequisite for advancing the BSTM program, providing a concrete timeline of early 2026 for its commencement. This progress on a second key asset diversifies the company's development pipeline beyond the San Marcial exploration success story.

However, the announcement is not material. The results are from channel sampling in a known, historically producing mine, not a new discovery. The market's primary focus has been on the resource expansion potential at San Marcial, which has delivered exceptional drill results (e.g., September 3, 2025: 75 m at 293 g/t AgEq). While positive, these sampling results are an expected confirmation of grade.

A significant point of concern is the resignation of the Vice President of Operations, Mr. Alejandro Cano, who was only appointed in June 2025. His departure at a time when the company is advancing towards a major operational undertaking (the BSTM program) is a red flag. While it may be for personal reasons, it introduces uncertainty regarding the execution and leadership of the Plomosas Mine development plan. This operational uncertainty tempers the otherwise positive technical update.

Overall, the news confirms the company is executing its stated plan for Plomosas but is overshadowed by the more significant exploration results at San Marcial and the unsettling management change in operations.

GR Silver Mining Ltd. is a Canadian-based, Mexico-focused mineral exploration company. Its flagship asset is the 100%-owned Plomosas Project, located in Sinaloa, Mexico. The project is an emerging high-grade silver district and contains two key areas: 1. San Marcial Area: The primary focus of recent exploration. A 2025 step-out drilling campaign has successfully delineated a wide, high-grade, shallow epithermal silver system with significant resource expansion potential. 2. Plomosas Mine Area: A past-producing underground silver-gold-lead-zinc mine operated by Grupo Mexico until 2000. It has significant existing infrastructure (7.4 km of underground development) and is permitted. The company is advancing this area towards a Bulk Sample Test Mining (BSTM) program.