GR Silver Mining Advances Bulk Sampling Permitting & Governance as Drilling Continues at Plomosas

• Mexico’s Secretaría de Medio Ambiente y Recursos Naturales (SEMARNAT) has determined that no new Environmental Impact Authorisation is required for the bulk sampling test mining (BSTM) programme, allowing the company to proceed with only secondary permitting.
• Pilot plant options identified and under evaluation for the bulk sampling programme, subject to safety, security and secondary permits.
• There are 3 rigs that are active on the 20,000-metre San Marcial drilling programme targeting second half 2026 completion, to be followed by an updated Mineral Resource Estimate (MRE) and Preliminary Economic Assessment (PEA).
• Eric Zaunscherb resigned as Executive Chair to focus on Interim President and Chief Executive Officer roles, with Larry Taddei appointed Lead Independent Director.
• Durango established as operational base for exploration to mitigate regional risk, with principal access road under upgrade to facilitate supply and egress. 

Company Overview

GR Silver Mining (TSX.V: GRSL | OTCQX: GRSLF | FRA: GPE) is a Canadian-based, Mexico-focused mineral exploration company engaged in silver and gold resource expansion on its 100%-owned Plomosas Project, located on the eastern edge of the Rosario Mining District in Sinaloa State, Mexico. The project covers 7,823 hectares and includes the former Plomosas underground mine and high-grade silver mineralised zones at the San Marcial Area.

Permitting Milestone Removes Key Constraint on Bulk Sampling Programme

GR Silver Mining has received official notification from Mexico’s Secretaría de Medio Ambiente y Recursos Naturales (SEMARNAT) that production of a new Manifestación de Impacto Ambiental (MIA) will not be required for the former Plomosas Mine. This determination is anchored in four factors: the existence of existing infrastructure, the company's plans to rehabilitate and modernise that infrastructure, no change in land use, and no expected increase in environmental impact or risk.

The decision enables GR Silver Mining to proceed with its bulk sampling test mining (BSTM) programme without the time and cost burden of producing a new MIA. Only secondary permitting is required, which is currently in process.

Engineering to support the BSTM programme has progressed, with several options concerning the purchase and installation of a pilot plant identified and under evaluation. Potential purchase and installation of the pilot plant is dependent on safety and security conditions, as well as securing all secondary permits. SEMARNAT previously granted the company a five-year drill permit in September 2025, authorising additional step-out and exploration drilling in the San Marcial Area of the Plomosas Project.

Interim President and Interim Chief Executive Officer of GR Silver Mining, Eric Zaunscherb, stated:

"It is essential that the Company maintain the trust of regulators at the State and Federal levels of Government as we advance the Plomosas Silver Project. The achievement of this most recent milestone is evidence that GR Silver Mining's permitting team is successfully doing so and delivering progress on behalf of shareholders. We are getting things done."

Drilling Programme Targets Second Half 2026 Completion

There are 3 rigs that are currently active on the 20,000-metre San Marcial step-out drill programme. The company pivoted earlier in 2026 to establish Durango as the base of operations for exploration, a decision framed as mitigating risk in a challenging region whilst allowing the programme to advance.

The principal secondary road from Durango to the Project is currently being upgraded to facilitate faster supply and egress. GR Silver Mining is targeting completion of the drill programme in the second half of 2026, with final timing dependent upon ongoing access.

An updated Mineral Resource Estimate (MRE) and a Preliminary Economic Assessment (PEA) integrating the Plomosas Mine Area and the San Marcial Area are scheduled to follow completion of the drilling programme.

Governance Restructuring Positions Board for Operational Focus

Eric Zaunscherb has resigned his position as Executive Chair of the Board of Directors to focus on the Interim President and Interim Chief Executive Officer roles. Director Larry Taddei has been appointed Lead Independent Director.

Taddei was appointed a Director of the company in January 2023 and has served on the Board of Directors and its Compensation Committee, which he chairs, and Audit Committee. He is a Chartered Professional Accountant and served as Chief Financial Officer of MAG Silver Corp. from 2010 to 2022, where he was involved in establishing governance guidelines, policies, and procedures, as well as expanding environmental, social and governance disclosures and policies.

Next Steps

The company is targeting completion of the 20,000-metre San Marcial step-out drill programme in the second half of 2026, subject to ongoing access conditions. Following completion of drilling, GR Silver Mining is scheduled to deliver an updated MRE and a PEA integrating the Plomosas Mine Area and the San Marcial Area.

Secondary permitting for the BSTM programme is in process. Purchase and installation of a pilot plant for the BSTM programme is contingent on safety and security conditions and completion of all secondary permits. The principal secondary road from Durango to the Project is currently under upgrade to facilitate faster supply and egress.

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