GR Silver Mining Expands San Marcial Footprint & Identifies a New Mineralised System

• Recent drilling intersected 21.9 metres true width grading 168 grams per tonne silver, including 6.15 metres grading 447 grams per tonne silver, extending mineralisation at least 150 metres beyond the 2023 Mineral Resource Estimate (MRE) boundary.
• The southeastern extension expands the resource area at San Marcial, which currently contains 46 million ounces of silver in indicated mineral resources and 14 million ounces in inferred mineral resources.
• Drilling within the Parallel Breccia target returned multiple silver-bearing intervals and intersected 0.75 metres grading 5.34 grams per tonne gold, supporting a separate mineralisation model.
• Management now believes the Parallel Breccia may represent a distinct mineralising event, creating an additional exploration target beyond the primary silver system.
• Recent drilling continues to validate a structural model in which fault intersections and dilation zones are associated with higher-grade mineralisation.
• The fully funded 20,000-metre drill program is targeting an MRE update in late 2026 and a Preliminary Economic Assessment (PEA) in the first half of 2027.

Extending the Existing Resource Footprint

GR Silver Mining's (TSXV: GRSL | OTCQX: GRSLF) latest drill results continue to expand the footprint of mineralisation at San Marcial. Recent drilling intersected 21.9 metres true width grading 168 grams per tonne silver, including 6.15 metres grading 447 grams per tonne silver, within the southeastern extension area being tested as part of the company's 20,000-metre drill program. The result confirms silver mineralisation at least 150 metres beyond the southeastern boundary of the 2023 Mineral Resource Estimate (MRE). Because the intercept extends a previously defined mineralised corridor rather than identifying an isolated occurrence, it supports the potential for additional resource growth through continued step-out drilling along strike.

The extension lies adjacent to a resource area that currently hosts 46 million ounces of silver in indicated mineral resources and 14 million ounces in inferred mineral resources. The latest intercept, therefore, expands the footprint of an established resource rather than opening an entirely new exploration front. Extensions of known mineralisation typically carry lower geological risk than new target generation, as they build on an existing resource model. 

President and Chief Executive Officer of GR Silver Mining, Eric Zaunscherb, contextualised the scale of the newly confirmed extensions:

"The very first thing I want to point out is that we're exploring a large system here on a district scale, and at the core of that is an intrusive body."

Management's focus on extending known mineralisation reflects a strategy designed to leverage an existing resource base. The company noted that historical drilling at San Marcial has generated approximately 4,000 ounces of silver per metre drilled. While future drilling outcomes will vary, the metric illustrates why the company continues to prioritise extensions around the current resource footprint rather than allocating exploration capital toward higher-risk greenfield targets.

The Parallel Breccia Opens a Second Resource Growth Opportunity

While recent drilling expanded the primary silver system, work within the Parallel Breccia target provided evidence that a separate mineralised target may be emerging within the district. Drilling returned multiple silver-bearing intervals and intersected 0.75 metres grading 5.34 grams per tonne gold. The significance of the result lies less in the initial gold intercept and more in what it suggests about the district's geological evolution. 

The company’s interpretation has shifted from viewing the Parallel Breccia as a direct analogue of the main San Marcial system to considering it a separate mineralising event with distinct structural controls and a stronger gold component. If confirmed through follow-up drilling, the target could provide resources independent of the current silver-focused growth strategy, increasing the number of mineralised systems capable of supporting future resource growth. 

Zaunscherb explained the company's adaptive targeting strategy:

"We're learning that it may be slightly different with more near-surface veins and bonanzas and disseminated mineralisation that may be more closely related to crosscut northeasterly structures. And if that's the case, what you have to do is turn the drills around, swing them by 90 degrees, and start testing what's happening along those crosscutting structures."

Structural Validation Improves Drill Targeting Confidence

The strongest silver intercept reported during the current program returned 45.1 metres true width grading 1,623 grams per tonne silver, including 8.25 metres grading 8,579 grams per tonne silver, from drilling designed to test a structural intersection identified by the company's geological model. The result validated management's structural targeting approach and demonstrated that fault-controlled dilation zones can host significantly higher grades than surrounding mineralisation. The outcome provides a repeatable framework that can be applied across future drill campaigns.

Recent results from both the southeastern extension and the Parallel Breccia target provide additional information regarding the relationship between mineralisation and structural controls. Each result contributes to management's understanding of where higher-grade mineralisation is most likely to occur, increasing confidence in future drill targeting and improving the efficiency of future exploration spending.

Funding, Infrastructure & Development Progress

The current drill campaign is supported by a cash balance of C$27.5 million reported as of March 31, 2026. Management identifies this funding as sufficient to advance the ongoing 20,000-metre drill program and planned technical studies, reducing near-term financing risk as the company advances toward an MRE update and Preliminary Economic Assessment (PEA). GR Silver Mining also controls the Plomosas Mine, located approximately 10 kilometres north of San Marcial. The former producing operation provides existing infrastructure, road access, power, permits, underground workings, and historical operating data that can be incorporated into future development planning.

The company identifies the completion of the drill program, an MRE update, a PEA, pilot-plant engineering activities, and bulk-sample test mining (BSTM) as key milestones. Each initiative is designed to generate technical information required for future development decisions, while collectively supporting management's objective of advancing San Marcial and Plomosas as an integrated development opportunity.

Implications for the 2026 MRE Update

The ongoing 20,000-metre drill program remains the primary catalyst for the remainder of 2026. Management stated during the interview that approximately 25% of the program has been completed, with assay results expected to be released in batches as drilling progresses. At the broader project level, the 2023 MRE contains 55 million ounces of silver in indicated mineral resources and 22 million ounces of silver in inferred mineral resources. The current campaign is designed to expand and upgrade that inventory through a combination of resource extensions and new discoveries.

The latest southeastern extension results extend mineralisation beyond the current resource boundary, while results from the Parallel Breccia target introduce a potentially separate mineralised system that could contribute additional resources if continuity is confirmed through future drilling. The late-2026 MRE update will be the foundation for an integrated PEA targeted for the first half of 2027. Results from the current drill program will therefore determine whether future resource growth is driven primarily by extensions of the existing silver system, the emerging Parallel Breccia target, or both.

Investment Thesis for GR Silver 

• Confirmation of silver mineralisation 150 metres beyond the current Mineral Resource Estimate boundary supports resource growth through extensions of an already defined deposit rather than requiring a new discovery.
• The identification of a separate gold-bearing mineralising system within the Parallel Breccia introduces an additional potential source of future resources beyond the project's existing silver inventory.
• Recent drilling continues to validate the company's structural targeting model, increasing confidence that future drilling can efficiently identify additional high-grade mineralisation.
• A fully funded 20,000-metre drill program is generating the data required for a late-2026 Mineral Resource Estimate update and an integrated Preliminary Economic Assessment targeted for the first half of 2027.
• The company's C$27.5 million cash position funds the current exploration and technical work programs, reducing near-term financing risk while management advances key project catalysts.

The latest drill results expand both the scale of the San Marcial resource opportunity and the number of exploration targets that can contribute to future resources. In addition to extending the primary silver system, the discovery of a potentially distinct gold-bearing mineralised corridor provides a second pathway for resource growth ahead of the next Mineral Resource Estimate update.

TL;DR

GR Silver Mining Ltd. has confirmed silver mineralisation at least 150 metres beyond the current San Marcial resource boundary, and has identified evidence of a separate gold-bearing mineralising system within the Parallel Breccia target. Both discoveries could contribute to an MRE update targeted for late 2026 and an integrated PEA  planned for the first half of 2027.

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