Mr. Eric Zaunscherb reports

GR SILVER DRILL PROGRAM DELIVERS HIGH-GRADE INTERCEPTS: 35.45 M AT 311 G/T AG, INCLUDING 0.4 M AT 4,232 G/T AG IN THE SE AREA, AND 2.15 M AT 1,164 G/T AG, 0.6% CU, AND 0.37% W IN THE PARALLEL BRECCIA TARGET

GR Silver Mining Ltd. has released continued positive drill results from the current 20,000-metre (m) drill program at San Marcial, Mexico, confirming the extension of high-grade zones in the southeast (SE) area and the continuity of the parallel breccia target located 300 m to the southwest of the 2023 National Instrument 43-101 resource area.

Highlights:

• Hole SMS26-19 returned 35.45 m true width (TW) at 311 grams per tonne (g/t) silver (Ag), including 0.4 m TW at 4,232 g/t Ag and 1.35 m TW at 996 g/t Ag, further confirming the extension of the high-grade silver mineralized system in the southeast area.
• Hole SMS26-17 returned 2.15 m TW at 1,164 g/t Ag, 0.6 per cent copper (Cu) and 0.37 per cent tungsten (W) in the separate parallel breccia target. This intercept is significant in that it may indicate a multiphase hydrothermal system, potentially reflecting a transition toward a porphyry-related mineralizing environment.
• The drill program has pivoted to further test the high-grade dilation zone extending from hole SMS26-04, which returned 45.1 m TW at 1,623 g/t Ag, including 8.25 m at 8,579 g/t Ag (see news release dated May 19, 2026).
• With the wet season finally winding down and the Durango access road upgrades nearly complete, it is expected that the pace of the continuing drill program will significantly increase going forward.

GR Silver Mining's president and chief executive officer, Eric Zaunscherb, commented: "The systematic approach to exploring the San Marcial mineralized system continues to bear fruit. These results provide important insights into mineralization hosted by the main hydrothermal breccia in the SE area and the potential extension of the higher-grade dilation zone(s) within. 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. As we emerge from this year's extensive wet season, our access road upgrade in Durango will allow us to accelerate our drill program, which should enable delivery of our planned MRE update by mid-2027. The safety and security of our employees, contractors and local communities remain our top priority, as we continuously monitor the security situation in and around the Plomosas project area.

Highlights of recent 2026 stepout drilling at San Marcial:

• SMS26-19 intersected a broad zone of chlorite-hematite-rich hydrothermal breccias extending across both the upper Oligocene volcanic sequence and the underlying Jurassic volcano-sedimentary sequence, primarily following the structurally controlled contact between these units. The drill hole also encountered an increased occurrence of dioritic dikes, which become more prominent toward the southeast extension and are interpreted to be associated with the Oligocene subvolcanic intrusive complex. The crosscutting relationships observed between the intrusive dikes and silver-lead-zinc mineralization provide important insights into the timing of the hydrothermal system. These relationships suggest that mineralization developed during a later hydrothermal event, following the emplacement of the Oligocene intrusive complex. Best results (table 1) include:
  • 35.45 m TW at 311 g/t Ag from 339.85 m downhole:
    • Including 0.4 m TW at 4,232 g/t Ag and 1.35 m TW at 996 g/t Ag.
• SMS26-17 confirms the continuity of the parallel breccia target, located approximately 300 m southwest of the 2023 NI 43-101 resource area. Drilling has now demonstrated mineralization continuity over 300 m along strike and 125 m downdip, with the system remaining open for further expansion in both directions. Mineralization is primarily associated with quartz-calcite-hematite-tourmaline hydrothermal breccias hosted within the lower Jurassic volcano-sedimentary sequence. These breccias are locally crosscut by stockwork veinlets associated with anomalous silver and gold values, suggesting multiple episodes of hydrothermal activity. The overlapping mineralization styles and alteration assemblages may indicate a multiphase hydrothermal system, potentially reflecting a transition toward a porphyry-related mineralizing environment. Best results (table 2) include:
  • 2.2 m TW at 1,164 g/t Ag, 0.6 per cent Cu and 0.37 per cent W, from 104.8 m downhole.

Drill hole SMS26-19 successfully intersected 35.45 m TW at 311 g/t Ag, including 0.4 m TW at 4,232 g/t Ag, further confirming the continuity of the high-grade silver mineralized system in the southeast area. This mineralized zone was initially identified near surface during the 2022 stepout drilling program in hole SMS22-14, which returned 10.5 m at 23 g/t Ag and 3.5 m at 118 g/t Ag, including 0.2 m at 1,790 g/t Ag (see news release dated Oct. 17, 2022). More recently, the same mineralized system was intersected by drill holes SMS26-06 and SMS26-07 as part of the current 20,000 m stepout drilling program, returning significant results of 21.9 m at 168 g/t Ag, including 6.15 m at 447 g/t Ag (see news release dated July 10, 2026). The SMS26-19 results have now extended the mineralization an additional 80 m downdip and demonstrate the vertical continuity of high-grade silver mineralization over at least 300 m, reinforcing the exploration potential for further expansion of the mineralized system at depth in the southeast area. As part of the current 20,000-metre stepout drilling program, two additional drill holes are planned on this section to further test the continuity of high-grade silver mineralization at depth and potentially extend the mineralized system to a total downdip extent of 500 m from surface. Holes SMS26-16 and SMS26-18 did not return encouraging values, requiring further evolution of our exploration model in this area.

Drill hole SMS26-17 successfully confirmed the continuity of high-grade silver mineralization within the parallel breccia target, intersecting 2.15 m TW at 1,164 g/t Ag, 0.6 per cent Cu and 0.37 per cent W hosted in a hydrothermal fault breccia. This distinctive silver-copper-tungsten (Ag-Cu-W) mineralization association was first recognized during the 2025 exploration drilling program in hole SMS25-10A, which returned 9.0 m at 374 g/t Ag, 0.3 per cent Cu and 0.59 per cent W, including 1.0 m at 1,542 g/t Ag, 1.4 per cent Cu and 0.62 per cent W (see news release dated Sept. 24, 2025).

The occurrence of sulphide-rich silver mineralization associated with anomalous copper and tungsten values, together with a tourmaline-actinolite-albite-K-feldspar alteration assemblage, suggests a relatively high-temperature hydrothermal environment potentially linked to a porphyry-related mineralizing system. This interpretation is further supported by the location of the parallel breccia within a high-chargeability geophysical anomaly in the lower volcano-sedimentary unit surrounding a Cretaceous granodioritic intrusive complex.

Additional drilling results have further demonstrated the continuity and exploration potential of the parallel breccia. Drill hole SMS26-08 intersected 19.9 m grading 206 g/t Ag, including 1.3 m at 932 g/t Ag (see news release dated Aug. 21, 2025). These results have outlined a mineralized structure extending approximately 300 m along strike and at least 150 m downdip, highlighting the potential for further expansion of high-grade silver mineralization within the parallel breccia system. Mineralization is present in hole SMS26-11 but poorly developed in this location.

Discussion

The current 20,000-metre stepout drilling program at San Marcial continues to deliver encouraging results, confirming the continuity and expansion potential of high-grade silver mineralization beyond the boundaries of the 2023 National Instrument 43-101 mineral resource estimate (MRE), following the chlorite-hematite hydrothermal breccia at the contact between upper Oligocene volcanics and lower volcano-sedimentary units. In the southeast extension, the intersection in drill hole SMS26-19 further supports the continuity of the mineralized system initially identified in 2022 and subsequently intersected during the 2026 drilling campaign. These results demonstrate the vertical continuity of high-grade silver mineralization over at least 300 m vertically. The association of high-grade silver mineralization trends with structural controls suggests a southeast-plunging mineralized system that remains open for further expansion at depth.

Drilling at the parallel breccia target, located approximately 300 m southwest of the existing MRE area, has outlined high-grade silver mineralization extending approximately 300 m along strike and at least 150 m downdip. In addition to the encouraging silver grades intersected in SMS26-17 and the increased size of the mineralized zone at the parallel breccia target, the recent drilling is providing valuable geological insights into the broader mineralizing environment at San Marcial. The association of silver with anomalous copper and tungsten, together with tourmaline-actinolite-albite-K-feldspar alteration, multiple hydrothermal breccia events and stockwork veining, suggests a complex, multiphase hydrothermal system potentially linked to a deeper porphyry-related environment.

These results strengthen confidence in the geological exploration model and highlight the opportunity to expand the known silver mineralization both laterally and at depth, while advancing the understanding of the district-scale mineral potential of San Marcial within the Plomosas project. Results highlight the potential for further resource expansion and the possible conversion of inferred mineral resources to the indicated category through additional drilling and improved geological confidence.

Table 3 summarizes the progress of the 2026 San Marcial stepout drill program. To date, 7,756 m have been drilled in 25 holes, with assays pending from six holes.

About the Plomosas project

The Plomosas project, including the recent high-grade silver discovery in the San Marcial southeast area, is emerging in 2026 as a high-grade silver district located on the southwestern edge of the Sierra Madre Occidental, at the border of Durango and Sinaloa, Mexico. The Plomosas project, covering 7,823 hectares (ha) and, including the historical Plomosas underground mine, benefits from existing mine infrastructure, road access and valid permits associated with past-producing mining sites. The district contains intermediate to low-sulphidation epithermal silver and gold mineralization, hosted in hydrothermal breccias and veins. Wide, high-grade, shallow hydrothermal breccias have been delineated in the San Marcial area, including the southeast area discovery. Stepout drilling continues in 2026, with continuous resource growth, principally targeting pure silver resources.

QA/QC (quality assurance/quality control) procedures

The company has implemented QA/QC procedures, which include the insertion of blank, duplicate and standard samples in all sample lots sent to SGS de Mexico S.A. de C.V. laboratory facilities in Durango, Mexico, for sample preparation and assaying. For every sample with results above Ag more than 100 parts per million ppm (over the limit), these samples are reassayed by SGS de Mexico. Core samples are represented by both HQ and NQ diameters, and samples are represented by one-half core split of original core. The analytical methods include four-acid digestion and inductively coupled plasma optical emission spectrometry, with lead fusion fire assay and a gravimetric finish for silver above overlimits. For gold assays, the analytical methods are lead fusion and atomic absorption spectrometry, lead fusion fire assay, and gravimetric finish for gold above overlimits (more than 10 ppm).

Qualified person

The qualified person under National Instrument 43-101, Standards of Disclosure for Mineral Projects, for this news release is Dr. Gilles Arseneau, PGeo, contractor from Arseneau Consulting Services Inc., who has reviewed and approved its contents.

About GR Silver Mining Ltd.

GR Silver Mining is a Canadian-based, Mexico-focused mineral exploration company engaged in cost-effective silver-gold resource expansion on its 100-per-cent-owned assets, located on the eastern edge of the Rosario mining district, in the southeast of Sinaloa state, Mexico. GR Silver Mining controls 100 per cent of the Plomosas project, including both the high-grade silver discovery at the San Marcial area and the former Plomosas underground mine. Recent discoveries in the 78-square-kilometre of highly prospective, advanced-stage exploration concessions position the company well for resource expansion at the Plomosas project.

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