GR Silver Mining Confirms 150-Metre Resource Extension at San Marcial; Targets 2026 Resource Update

• GR Silver Mining confirmed silver mineralisation extending at least 150 metres beyond the southeastern boundary of its 2023 Mineral Resource Estimate (MRE) at the San Marcial Area in Sinaloa, Mexico.
• The drill hole intersected 21.9 metres true width grading 168 grams per tonne silver, including 6.15 metres grading 447 grams per tonne silver.
• The results form part of an ongoing 20,000-metre drill program designed to expand the existing resource footprint ahead of a planned MRE update.
• The company is targeting an updated Mineral Resource Estimate (MRE) in late 2026, followed by a Preliminary Economic Assessment (PEA) in the first half of 2027.
• GR Silver Mining reported C$27.5 million in cash as of March 31, 2026, which the company says will fund the drill program and planned technical studies.

What Has Happened

GR Silver Mining Ltd. (TSXV: GRSL; OTCQX: GRSLF) has reported new drill results from its San Marcial Area in Sinaloa, Mexico, confirming silver mineralisation extending at least 150 metres beyond the southeastern boundary of the company's 2023 Mineral Resource Estimate (MRE). The results form part of an ongoing 20,000-metre step-out drilling campaign designed to expand the existing resource footprint ahead of an updated MRE targeted for late 2026 and a Preliminary Economic Assessment (PEA) targeted for the first half of 2027.

The latest drilling results add to a growing dataset from the San Marcial discovery area, where the company is evaluating the potential to expand mineralisation beyond the limits of the current resource estimate. The drill program is one of several planned catalysts intended to support the next stage of project evaluation.

Step-Out Drilling Extends Mineralisation Beyond Current Resource

The new results were reported from the SE Extension target, where one drill hole intersected 21.9 metres true width grading 168 grams per tonne silver, including 6.15 metres grading 447 grams per tonne silver. The company stated that the intercept confirms continuity of the San Marcial hydrothermal breccia system beyond the current resource boundary.

The hole was drilled approximately 150 metres southeast of the existing MRE footprint and supports the company's objective of expanding the known mineralised system through step-out drilling. The result demonstrates continuity of silver mineralisation outside the limits of the current resource model and provides a new target area for follow-up drilling.

The latest intercept follows previously reported results from another drill hole, which returned 45.1 metres true width grading 1,623 grams per tonne silver, including 18.85 metres grading 3,846 grams per tonne silver and 8.25 metres grading 8,579 grams per tonne silver. 

President & Chief Executive Officer of GR Silver, Eric Zaunscherb, discussed the broader exploration opportunity:

"We've only covered about 20% of the perimeter of that intrusive, so that other 80% of the perimeter of the intrusive is prospective."

Additional Targets Support Resource Growth

In addition to the SE Extension results, drilling at the Parallel Breccia target intersected near-surface silver stockwork mineralisation together with a distinct gold-bearing structure in the drill hole. The company said the results demonstrate the presence of multiple mineralised systems within the broader San Marcial discovery area.

The Parallel Breccia zone, which was discovered in 2025, provides a second exploration front alongside the SE Extension area and offers additional opportunities to expand mineralisation beyond the current resource boundary. Ongoing drilling is focused on evaluating both the continuity of known breccias and the potential for additional discoveries around the intrusive centre.

20,000-Metre Program Advances Toward MRE Update

The current 20,000-metre drill campaign is intended to support expansion of the existing resource base and provide the foundation for an updated MRE. The company continues to focus drilling on extensions of known mineralisation while testing new targets identified through geological interpretation. According to the company's 2023 MRE, the Plomosas Project contains 55 million ounces of silver and 85 million silver-equivalent ounces in the Indicated category, plus 22 million ounces of silver and 49 million silver-equivalent ounces in the Inferred category.

Zaunscherb commented on the upcoming exploration milestones:

"Over the next 12 months, we have a good number of catalysts. We have a 20,000-metre drill program; we're going to have constant news flow from that. That will be followed by a mineral resource estimate update, which will then be followed by a PEA."

GR Silver Mining is targeting completion of an updated MRE following the current drill campaign. The updated estimate is expected to incorporate results from the ongoing step-out program and provide the basis for future economic studies. The company is then targeting completion of a PEA in the first half of 2027. The MRE update and PEA are among the company's primary development catalysts as it advances the Plomosas Project.

Existing Infrastructure Supports Ongoing Development Work

The San Marcial discovery forms part of the Plomosas Project in Sinaloa, Mexico, located near the fully permitted, past-producing Plomosas Mine. The existing project infrastructure and permitting framework provide the operational setting for both ongoing exploration and future technical studies.

GR Silver Mining reported a cash position of C$27.5 million as of March 31, 2026. The current treasury is intended to fund the ongoing drill campaign while advancing additional development activities, including the planned MRE update, PEA, Bulk Sample Test Mining (BSTM) Program and pilot plant engineering initiatives. The combination of continued drilling, a fully funded exploration program and a defined pathway toward updated technical studies positions San Marcial as the company's primary focus through the remainder of 2026 and into 2027.

FAQs (AI-Generated)

‍