GRSL.V · 2025-08-21 12:00:00

GR Silver Mining Drills Wide Silver Intercepts at San Marcial: SMS25-08 Returned 19.9 m at 250 g/t AgEq*, Including 1.3 m at 954 g/t AgEq and a New Gold-Silver Mineralized Vein of 1.0 m at 1,685 g/t AgEq

Drill Results

GR Silver Mining Drills Wide Silver Intercepts

at San Marcial: SMS25-08 Returned 19.9 m at

250 g/t AgEq*, Including 1.3 m at 954 g/t AgEq

and a New Gold-Silver Mineralized Vein of 1.0

m at 1,685 g/t AgEq

VANCOUVER, BC

Aug. 21, 2025

/CNW/ -

GR Silver Mining Ltd.

GR Silver Mining

" or the

Company

") (TSXV: GRSL) (OTCQB: GRSLF) (FRANKFURT: GPE) – is pleased to announce

drilling results from the ongoing Step-Out Drilling Program (Step-Out Drilling) adjacent to the 2023 NI

43-101 mineral resource (Resource Area) at the San Marcial Area, Plomosas Project,

Sinaloa,

Mexico

Drilling at the Parallel Breccia target that hosts the latest results is designed to explore the down-dip

continuity of anomalous surface channel silver results in the vicinity of the Resource Area boundary,

stepping out to the west along major northeast-oriented faults (Figure 1).

Drilling activity on site remains focused on exploring the potential to increase the Resource Area in

the three principal targets outlined in Figure 1. Assay results are pending from drill holes currently

being drilled down-plunge in the SE Deep Extension of the Resource Area.

Highlights of Step-Out Drilling at the Parallel Breccia Target, San Marcial (Figure 1 and Table

1):

SMS25-08

was drilled to test the down-dip continuity of silver mineralization 45 metres below

historical trench results (SMTr-022:

24 m

at 219 g/t AgEq), targeting a perpendicular orientation

to the northeast structures and their intersections with northwest-oriented regional structures,

for the first time. The presence of mineralization at these intersections oriented towards the

northeast represents a potential opportunity for resource expansion at this target.

SMS25-08

intersected a wide, predominantly silver-mineralized intercept hosted in hydrothermal

breccia,

19.9 m

at 250 g/t AgEq

, starting at a shallow down-hole depth of 21.5 metres and

includes a high-grade silver intercept,

1.3 m

at 954 g/t AgEq

SMS25-08

also includes multiple zones with attractive results that are within the wide silver

mineralized zone, such as

3.7 m

at 557 g/t AgEq

and

4.2 m

at 350 g/t AgEq.

SMS25-08

was extended to a depth of 244.5 metres to investigate the presence of silver and

gold mineralization related to northeast-oriented structures on the edge of the large

chargeability geophysical anomaly. The hole successfully discovered a new high-grade gold-

silver epithermal vein grading

1,685 g/t AgEq (24.6 g/t Au and 13 g/t Ag), over

1.0 m

SMS25-07A

was drilled to test the continuity of silver mineralization 125 metres along strike

from SMS25-04, which contained

36 m

at 114 g/t AgEq.

SMS25-07A

intersected multiple zones of wide silver mineralization at shallow depth, including

11.1 m

at 71 g/t AgEq, representing a target for future drilling follow-up at depth.

GR Silver Mining's President and CEO,

Marcio Fonseca

, commented,

Each batch of drill results

received from the step-out drilling program increases the prospective scale of the San Marcial

Area, potentially unlocking a much larger resource. The continuity of high silver grades and broad

widths of predominant silver

mineralization

encountered at shallow depths, as revealed by the

step-out drilling, supports the opportunity to continue drilling and expanding resources in the

vicinity of the San Marcial Resource Area. We await additional assay results now from the SE

Deep Extension target, which we believe will potentially lead to an extension of mineralization

below existing resource boundaries.

Figure 1 Location Map - Step-Out Drilling Program and Intrusive Related Chargeability Anomaly

(CNW Group/GR Silver Mining Ltd.)

Table 1: Drilling Highlights – Parallel Breccia Target

Drill Hole

From

(m)

Type

Interval

(m)

AgEq*

g/t

SMS25-07A

0.0

11.1

Hydrothermal

Breccia

11.1

0.08

0.1

28.8

51.7

Hydrothermal

Breccia

22.9

0.06

0.1

SMS25-08

21.5

41.4

Hydrothermal

Breccia

19.9

250

206

0.10

0.3

0.6

(Incl)

22.3

26.0

Hydrothermal

Breccia

3.7

557

511

0.20

0.8

0.3

(Incl)

24.7

26.0

Hydrothermal

Breccia

1.3

954

932

0.10

0.2

(Incl)

30.0

34.2

Hydrothermal

Breccia

4.2

350

322

0.10

0.1

0.4

(Incl)

33.0

33.4

Hydrothermal

Breccia

0.4

1,030

976

0.08

0.2

0.9

(Incl)

212.4

213.4

Epithermal

Vein

1.0

1,685

24.6

0.1

Note:

Numbers may be rounded. Results are uncut and undiluted. True width not estimated as the Company does not have sufficient data from the new mineralized zones to

determine the true widths of the intervals with any confidence.

* AgEq calculations using US$22.00/oz Ag, US$1,750/oz Au, US$0.90/lb Pb, US$1.10/lb Zn and US$3.00/lb Cu, with metallurgical recoveries of Ag – 94%, Au – 80%, Pb – 59%,

and Zn – 80%. Ag Eq = ((Ag grade x Ag Price x Ag recovery) + (Au grade x Au price x Au recovery) + (Pb grade x Pb price x Pb recovery) + (Zn grade x Zn price x Zn recovery) +

(Cu grade x Cu price x Cu recovery)/(Ag price x Ag recovery)

Drilling is ongoing with two diamond drill rigs, focusing on the SE Deep Extension target and the

Parallel Breccia target. The discovery of high-grade silver and gold mineralization at relatively

shallow depth, combined with the interpretation of the intersection of northeast and northwest

structures, suggests that the Resource Area remains open in multiple directions. The Company

continues to gain a detailed understanding of the geometry of mineralization by using oriented core

sampling combined with 3D structural and geochemical modelling.

The recently updated geological map (Figure 2), integrating all recent 3D modelling, is delineating a

regional intrusive related system with development of potential hydrothermal breccias, hosting silver

mineralization in association with regional faults and high porosity and permeability volcanic units.

Encouraging results from the drill program to date support opportunities for potential resource

expansion at the San Marcial Area.

Figure 2 Geological Map San Marcial Area – Step-Out Drilling Targets (CNW Group/GR Silver

Mining Ltd.)

Table 2: 2025 San Marcial Step-Out Drill Program – Drill Hole Details

Drill Hole

Target

East (m)

North (m)

RL (m)

Dip (˚)

Azimuth

(˚)

Depth

(m)

Results

Status

SMS25-01

NW Extension

450685

2546064

914

-60

160

247.8

Abandoned

SMS25-02

NW Extension

450568

2546102

942

-55

135

206.0

Abandoned

SMS25-03

Parallel Breccia

450955

2545667

862

-60

135

206.0

Received

SMS25-04

Parallel Breccia

451045

2545757

860

-55

185

159.0

Received

SMS25-05

NW Extension

450791

2545967

892

-47

227

176.7

Received

SMS25-06

NW Extension

450797

2546016

895

-74

225

191.8

Received

SMS25-07A

Parallel Breccia

451145

2545641

795

-76

200

118.2

Received

SMS25-08

Parallel Breccia

451085

2545808

835

-65

175

244.5

Received

SMS25-09

SE Deep Extension

451506

2545924

700

-60

130

TBD

Drilling

SMS25-10

Parallel Breccia

451506

2545924

700

-60

130

TBD

Drilling

SMS25-11

SE Deep Extension

451262

2545587

708

-81

143

TBD

Planned

SMS25-12

SE Deep Extension

451313

2546012

799

-68

270

TBD

Planned

Note: all holes drilled from surface; WGS84 Datum; TBD - To be defined

About the Plomosas Project

The Plomosas Project, including the recent high-grade silver discovery in the San Marcial SE Area,

is progressing in 2025 as an emerging high-grade silver district located in southwestern edge of the

Sierra Madre Occidental,

Sinaloa, Mexico

. The Plomosas Project, covering 43,187 ha, including the

historical Plomosas Underground mine. benefits from mine infrastructure, road access and existing

permits associated with past-producing mining sites. The district contains intermediate to low-

sulfidation epithermal silver and gold mineralization, hosted in hydrothermal breccias and veins.

Recent success in exploration and drilling has delineated wide, high-grade, shallow hydrothermal

breccias in the San Marcial Area, including the SE Area discovery, where step-out drilling is

underway in 2025, aiming for continuous resource growth. At the historical Plomosas Mine, where

Grupo Mexico operated the underground mine from 1985 to 2000, exploration, underground

sampling and metallurgical programs are being conducted to support future decisions regarding the

implementation of a Bulk Sampling Test Mining Program

QA/QC 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 México, S.A. de C.V. laboratory facilities in

Durango, Mexico

, for sample preparation and assaying. For every sample with results above Ag >

100 ppm (over the limit), these samples are re-assayed by SGS de

Mexico

. Core samples are

represented by both HQ and NQ diameters and samples are represented by ½ 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 over

limits. For gold assays, the analytical methods are Lead Fusion and Atomic Absorption

Spectrometry, Lead Fusion Fire Assay, and gravimetric finish for gold above over limits (>10 ppm).

Qualified Person

The Qualified Person under National Instrument 43-101 Standards of Disclosure for Mineral Projects

for this news release is

Marcio Fonseca

, P. Geo., President & CEO for GR Silver Mining, 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%-owned assets, located on the eastern

edge of the Rosario Mining District, in the southeast of Sinaloa State,

Mexico

. GR Silver Mining

controls 100% of the Plomosas Project, including the former Plomosas underground mine and wide,

high-grade silver mineralized zones at the San Marcial Area. Recent discoveries in the 78 km² of

highly prospective, advanced-stage exploration concessions position the Company well for resource

expansion at the Plomosas Project.

GR Silver Mining Ltd.

Márcio Fonseca, President & CEO,

Cautionary Statement Regarding Forward-Looking Information

This press release contains "forward-looking statements" within the meaning of applicable

Canadian securities legislation and information that are based on the beliefs of management and

reflect the Company's current expectations. When used in this press release, the words "estimate",

"project", "belief", "anticipate", "intend", "expect", "plan", "predict", "may" or "should" and the

negative of these words or such variations thereon or comparable terminology are intended to

identify forward-looking statements and information. Such statements and information reflect

the current view of the Company. Risks and uncertainties may cause actual results to differ

materially from those contemplated in those forward-looking statements and information. By their

nature, forward-looking statements involve known and unknown risks, uncertainties and other

factors which may cause our actual results, performance or achievements, or other future events,

to be materially different from any future results, performance or achievements expressed or

implied by such forward-looking statements.

Neither the TSX Venture Exchange nor its Regulation Services Provider (as that term is

defined in the policies of the TSX Venture Exchange) accepts responsibility for the adequacy

or accuracy of this press release.

SOURCE

GR Silver Mining Ltd.

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For further information:

For further information, please contact: Telephone: +1 236-270-2057,

Email: [email protected]

CO: GR Silver Mining Ltd.

CNW 06:00e 21-AUG-25

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