GRSL.V · 2025-09-03 12:00:00

GR Silver Mining Intersects Extensive High- Grade Epithermal Silver System. SMS25-09 Returns 75 m at 293 g/t AgEq, including 6.4 m at 1,915 g/t AgEq

Drill Results

GR Silver Mining Intersects Extensive High-

Grade Epithermal Silver System. SMS25-09

Returns 75 m at 293 g/t AgEq, including 6.4 m

at 1,915 g/t AgEq

VANCOUVER, BC

Sept. 3, 2025

/CNW/ -

GR Silver Mining Ltd.

GR Silver Mining

" or the

Company

") (TSXV: GRSL) (OTCQB: GRSLF) (DEU: GPE) is pleased to announce a 75 metre

wide (down-hole) silver intercept, including multiple high-grade (>1,000 g/t Ag) intervals, from the

current Step-Out Drilling Program. Drill hole SMS25-09 returned a

75 m

wide intercept at 293 g/t

AgEq,

including high-grade silver interval up to

6.4 m

at 1,915 g/t AgEq

. This excellent result has

expanded the mineralized footprint, extending high-grade mineralization by an

additional 100 metres

below the previous resource outline

("Resource Area") at the San Marcial Area of the Plomosas

Project in

Sinaloa, Mexico

Highlights of Step-Out Drilling at SE Deep Extension Target, San Marcial

SMS25-09 intersected

75 m

@ 293 g/t AgEq, including multiple intervals exceeding 1,000

g/t AgEq.

The hole tested 3D geophysical anomalies and successfully confirmed continuity of the

main high-grade mineralized structures at least

100 m

beyond the Resource Area.

Drilling returned a broad,

75 m

wide, silver-dominant zone with frequent boiling textures,

multiple phases of silver mineralization, and selective gold mineralization.

High-grade gold values were encountered in several intervals, confirming the presence

of both silver and gold mineralization at depth.

SMS25-09 also intersected a wide chlorite–hematite hydrothermal breccia within a

favorable structural setting formed by intersecting NW–NE regional structures. This

configuration may host sizeable geological traps in porous volcanoclastic rocks,

significantly enhancing the potential for resource expansion at San Marcial.

The high-grade silver mineralization remains open down-dip.

Drilling at the SE Extension target (Figure 1) has confirmed the continuation of wide, high-grade

silver mineralization, extending 100 metres horizontally beyond the current Resource Area.

Compelling geological and geochemical studies point to the presence of a large, well-preserved

silver-rich system linked to a recently identified regional porphyry intrusive setting, underscoring the

potential for significant future resource growth. Hole SMS25-09 (

75 m

@ 293 g/t AgEq) continues to

demonstrate the continuity of this significant silver-mineralized system, which was discovered in hole

SMS22-10 (

101.6 m

@ 308 g/t Ag) located 250 metres to the northwest (Figure 2-Geological Map

and 3-Longitudinal Section).

Successful drilling at the SE Extension is also confirming the continuity of wide, high-grade silver

zones at depth, with results pointing to a potential extension of mineralization for at least 450 metres

vertically from surface. Favorable alteration and mineralogical indicators support this growth

potential, with hole SMS25-09 notably displaying epithermal boiling textures (Figure 4), indicating a

well-preserved silver system that remains open at depth.

GR Silver Mining's President and CEO,

Marcio Fonseca

, commented,

"Step-Out drilling at San

Marcial has delivered strong results, confirming wide zones of high-grade, silver-dominant

mineralization 450 metres below surface. Guided by advanced geological work and 3D modelling,

this first-ever step-out drilling campaign has successfully tested extensions of the San Marcial

epithermal silver rich system. The transition of mineralization with depth, highlighted by changes in

alteration and lithology, supports our interpretation of a robust epithermal system hosted along the

northern edge of a large, regional porphyry intrusive setting. The results demonstrate significant

potential for future resource growth, marking a key milestone that opens the door for continued

expansion beyond current boundaries. We congratulate our geological team for this achievement,

which provides encouragement for substantial exploration success in upcoming San Marcial

drilling."

Figure 1 Location Map – Drill Hole SMS25-09 Location in the Current Step-Out Drilling Program and

Intrusive Related Chargeability Anomaly (CNW Group/GR Silver Mining Ltd.)

Table 1: SMS25-09 Drilling Highlights – SE Extension Resource Expansion Target

Drill Hole

From

(m)

Type

Interval

(m)

AgEq*

g/t

SMS25-09

158.8

162.6

Hydrothermal

Breccia

3.8

0.12

0.2

0.8

SMS25-09

263.9

339.1

Hydrothermal

Breccia

75.2

293

260

0.1

0.2

0.5

(Incl)

296.8

303.2

Hydrothermal

Breccia

6.4

1915

1853

0.04

0.3

1.0

(Incl)

336.5

338.3

Hydrothermal

Breccia

1.8

1759

1363

1.10

2.42

5.4

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)

Successful drilling at the SE Deep Extension target has confirmed the continuity of mineralization 100

metres beyond the Resource Area, intersecting wide, predominantly chlorite–hematite-rich

hydrothermal breccia with notable epithermal features, including:

Boiling textures with calcite and high-grade silver (argentite and acanthite) hosted within

hydrothermal breccia zones (Figure 4), indicating possible proximity to the high-grade core of an

epithermal system that remains open both down dip and down plunge (Figure 3).

Geochemical modelling suggests that the Resource Area represents the upper portion of a

much larger epithermal system, hosted along the edge of a regional porphyry intrusive setting.

Continuous calcite, barite, and fluorite concentrations indicate that this zone lies near the top of

a well-preserved system, controlled by intersecting NW- and NE-trending regional faults.

The recently updated geological map (Figure 2) highlights three areas currently under investigation

by the Step-Out Drilling Program. The success of drill hole SMS25-09 at the SE Deep Extension

target strongly supports continued testing of extensions of the wide, high-grade silver mineralization.

Follow-up drilling aims to test the system an additional 100 metres down plunge. Drill hole SMS25-

11, currently in progress, along with the planned SMS25-12 (Figures 1, 2 and 3), are designed to

test further extensions, supporting the potential for future resource expansion.

Figure 2 Geological Map San Marcial Area – Step-Out Drilling Targets – Location Figure 4 (CNW

Group/GR Silver Mining Ltd.)

Figure 3 Longitudinal Section – Location holes SMS25-09 and SMS22-10 (CNW Group/GR Silver

Mining Ltd.)

Figure 4 Drill Core Photo Illustration - SMS25-09 “Epithermal Boiling Textures” (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

Extension

450685

2546064

914

-60

160

247.8

Abandoned

SMS25-02

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

Extension

450791

2545967

892

-47

227

176.7

Received

SMS25-06

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

424.20

Received

SMS25-10

Parallel

Breccia

451506

2545924

700

-60

130

TBD

Pending

SMS25-11

Extension

451262

2545587

708

-81

143

TBD

Drilling

SMS25-12

Extension

451313

2546012

799

-68

270

TBD

Drilling

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

procedures, which include the insertion of blank, duplicate,

and standard samples in all sample lots sent to

SGS

México

S.A.

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

Mexico

. Core samples are

represented by both HQ and

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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http://www.newswire.ca/en/releases/archive/September2025/03/c9355.html

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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 03-SEP-25

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