A Repeating Silver-Copper-Tungsten Signature Sets Up GR Silver's Porphyry Test at San Marcial

• GR Silver Mining's Parallel Breccia Target, separate from the Southeast Area, returned 2.15 meters (m) true width (TW) at 1,164 grams per tonne (g/t) silver, 0.6% copper & 0.37% tungsten.
• The same silver-copper-tungsten association appeared in a 2025 hole at 374 g/t silver over 9.0 m, so the signature now repeats across 2 holes.
• The Parallel Breccia lies about 300 m southwest of the 2023 NI 43-101 resource area, with mineralization traced over 300 m along strike and open in both directions.
• A Southeast Area hole returned 35.45 m TW at 311 g/t silver and extended the high-grade system 80 m down-dip to at least 300 m of vertical continuity.
• The company has drilled 7,756 m of its 20,000 m program, reports C$26 million in cash as of June 30, 2026, and plans deeper holes into the central intrusive body later in the program.

GR Silver Mining (TSXV: GRSL | OTCQX: GRSLF | FRA: GPE) has repeated the silver-copper-tungsten signature first recognized in 2025 at the Parallel Breccia Target, and plans to test the central intrusive body at San Marcial with deeper holes later in its 20,000 meters (m) drill program. The assays reported on November 11, 2026 also include a 35.45 m intercept in the Southeast Area. Both targets sit in the San Marcial Area of the Plomosas Project, on the border of Durango & Sinaloa in Mexico.

A Second Hole Repeats the Silver-Copper-Tungsten Signature

The Parallel Breccia hole intersected 2.15 m true width (TW) at 1,164 grams per tonne (g/t) silver, 0.6% copper & 0.37% tungsten in hydrothermal fault breccia. The association first appeared in a 2025 hole that returned 9.0 m at 374 g/t silver, 0.3% copper & 0.59% tungsten, including 1.0 m at 1,542 g/t silver, 1.4% copper & 0.62% tungsten. Silver, copper & tungsten now appear together in 2 holes.

Mineralization at the Parallel Breccia is traced over 300 m along strike, remains open in both directions, and lies about 300 m southwest of the 2023 NI 43-101 resource area. The 2023 resource across the Plomosas Project totals 55 million ounces of silver Indicated & 22 million ounces Inferred, and the drill program targets extensions beyond that boundary.

Geology Points Toward the Central Intrusive

The Parallel Breccia sits within a high-chargeability geophysical anomaly in the lower volcano-sedimentary unit, around a Cretaceous granodioritic intrusive complex. Mineralization is hosted primarily in quartz-calcite-hematite-tourmaline hydrothermal breccias within the lower Jurassic volcano-sedimentary sequence, and those breccias are locally crosscut by stockwork veinlets associated with anomalous silver & gold, which the company reads as multiple episodes of hydrothermal activity.

Sulfide-rich silver mineralization with anomalous copper & tungsten, together with a tourmaline-actinolite-albite-K-feldspar alteration assemblage, suggests a relatively high-temperature hydrothermal environment. The company interprets that environment as potentially linked to a porphyry-related mineralizing system.

GR Silver describes the San Marcial discovery as lying on the edge of a potential new porphyry system. The company discovered the Parallel Breccia zone in 2025, and the San Marcial geophysical anomaly remains largely untested.

President & Chief Executive Officer of GR Silver Mining, Eric Zaunscherb, linked the result to the next step in the program:

"Further, the distinct mineralization and alteration intersected within the separate Parallel Breccia Target continues to support a potential porphyry model, which we plan to test with deeper holes into the central intrusive body later in this program."

Southeast Area Extends Vertical Continuity

The Southeast Area hole returned 35.45 m TW at 311 g/t silver, including 0.4 m TW at 4,232 g/t silver & 1.35 m TW at 996 g/t silver, in a chlorite-hematite-rich hydrothermal breccia. The result extends mineralization 80 m down-dip and shows vertical continuity of at least 300 m in a zone first identified near the surface in 2022 drilling.

Plans call for 2 more holes on the same section to test continuity at depth, potentially extending the system to a total down-dip extent of 500 m from the surface. The program has also pivoted to test the high-grade dilation zone extending from the hole reported May 19, 2026 that returned 45.1 m TW at 1,623 g/t silver, including 8.25 m at 8,579 g/t silver.

Funded Drilling Runs Into the 2027 Resource Update

GR Silver has drilled 7,756 m in 25 holes of the 20,000 m program, with assays pending from 6 holes. The company is targeting a faster pace as the wet season ends and the Durango access road upgrades near completion, and reports being fully funded with C$26 million in cash as of June 30, 2026.

The company has 5 catalysts planned: the drill program, a resource update, a preliminary economic assessment, bulk sample test mining at the permitted Plomosas Mine & pilot plant engineering.

The company now runs 2 targets inside 1 funded program. The Southeast Area follows a high-grade silver system to depth, and the Parallel Breccia adds a repeating silver-copper-tungsten signature that points toward the central intrusive body. Both feed the resource update the company is targeting in 2027.

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