GR Silver Mining Advances Plomosas Development as Silver's Industrial-Safe Haven Duality Strengthens Investment Case

• Phase II sampling at Plomosas Mine returned standout intercepts including 6.7m at 1,040 g/t AgEq and 4.2m at 1,018 g/t AgEq, confirming accessible mineralization for near-term bulk sampling.
• The company has mapped 21 underground areas and identified previously blasted high-grade material, targeting early 2026 commencement of on-site pilot processing.
• Current 85 Moz AgEq Indicated and 49 Moz AgEq Inferred resource base shows clear growth trajectory, with 2026 resource update and preliminary economic assessment planned.
• CAD$13.8 million treasury provides 15-month runway with no debt, supporting aggressive step-out drilling at San Marcial discovery zone where 80% of intrusive-related geophysical anomalies remain untested.
• Permitted 600 tpd underground mine with 7.4 km of accessible development and surface land ownership positions GR Silver Mining for low-capex development in Mexico's established Rosario Mining District.

Silver Miners Gain Leverage as Metal Tests $50/oz Resistance

GR Silver Mining Delivers Positive Progress on Phase II Underground Sampling at Plomosas Mine

Silver's recent climb toward the $50/oz resistance level has renewed institutional focus on development-stage producers capable of delivering near-term production growth. Vancouver-based GR Silver Mining Ltd. (TSXV:GRSL, OTCQB:GRSLF) is positioning itself within this cohort through systematic underground sampling at its 100%-owned Plomosas Project in Sinaloa, Mexico. The company's October 15, 2025 announcement of Phase II Bulk Sample Test Mining results demonstrates both geological continuity and operational readiness at a historical mine that produced over 3 million ounces of silver annually during Grupo México's 1986-2000 operations.

The timing aligns with silver's cross-currents between industrial demand and safe-haven flows. While Federal Reserve policy signals and US dollar strength will dictate short-term price action, the metal's dual role as both industrial commodity and monetary hedge provides support across macro scenarios. For mining equities, this creates a valuation window where companies demonstrating resource growth and development progress can capture investor attention before broader sector re-rating occurs.

GR Silver Mining's Plomosas Project sits within the Rosario Mining District's southwestern edge, where intermediate- to low-sulfidation epithermal systems have historically delivered bulk-tonnage silver deposits. The company controls 7,823 hectares including the former Plomosas underground mine and the San Marcial discovery area, where 2025 drilling has expanded the known mineralized footprint. With a current market capitalization of CAD$146 million against a 134 Moz AgEq total resource base, the company trades at approximately $1.09 per AgEq ounce in the ground—a meaningful discount to producing peer valuations that typically range $3-8 per ounce depending on jurisdiction and grade.

Company Overview: Dual-Track Development and Exploration Strategy

GR Silver Mining operates two parallel value-creation streams within the Plomosas Project. The first centers on the historical Plomosas Mine, where the company is advancing a Bulk Sample Test Mining program designed to validate grade reconciliation, metallurgical recoveries, and processing parameters ahead of potential pilot plant installation. The second focuses on the San Marcial Area, a 68 Moz AgEq resource zone discovered through systematic surface sampling and IP geophysics, where step-out drilling in 2025 has extended mineralization beyond the March 2023 NI 43-101 resource shell.

This dual approach allows GR Silver Mining to de-risk development capital through incremental cash flow from bulk sampling while simultaneously expanding the resource base that will underpin future economic studies. The strategy mirrors successful models employed by mid-tier producers in Mexico's prolific silver districts, where underground access and existing permits reduce the timeline and capital intensity typically associated with greenfield development.

The company's management team brings relevant operational experience from major and mid-tier producers. President and CEO Marcio Fonseca previously held senior roles with Echo Bay Mines, SilverCrest Mines, Phelps Dodge, and Vale, while also serving as Division Director for Macquarie Bank's Metals and Energy group where he managed the $150 million acquisition of SilverCrest Mines by First Majestic. Executive Chairman Eric Zaunscherb spent three decades as a mining equity analyst at Canaccord Genuity, providing institutional investor perspective on valuation and capital markets access.

Phase II Underground Sampling Results: High-Grade Zones Confirmed

The October 15 announcement detailed results from Phase II channel sampling across 21 underground locations within the historical Plomosas Mine. Standout intercepts included 6.7 meters at 1,040 g/t silver equivalent on Level 975, consisting of 903 g/t silver, 0.03 g/t gold, 1.4% lead, and 1.7% zinc. A second interval on the same level returned 1.2 meters at 2,365 g/t AgEq, composed of 2,264 g/t silver with elevated zinc grades.

High-grade gold mineralization also appeared in the Ramp 3 area, where 4.2 meters averaged 1,018 g/t AgEq including a 0.5-meter interval grading 35.7 g/t gold. These results confirm sulphide-rich unmined zones remain accessible within the historical workings, supporting the company's thesis that previous operators left significant mineralization in place due to metal price environments and processing technology constraints at the time.

"Ongoing underground channel sampling at the historic Plomosas Mine has delineated additional high-grade mineralized zones that are accessible for future BSTM.The confirmation of sulphide-rich, unmined areas that also contain high-grade silver and gold mineralization further supports the Company's plans to advance the implementation of the BSTM at Plomosas."

Strategic Significance: Bulk Sampling as Exploration and Development Tool

GR Silver Mining's Bulk Sample Test Mining program serves dual purposes. First, it provides geological validation through large-sample metallurgical testing that reduces technical risk ahead of feasibility-level studies. The company completed a similar program at the nearby San Juan historical mine in 2024, processing 20,430 tonnes through a third-party mill and producing 420 tonnes of lead-silver-gold concentrate averaging 8,357 g/t silver and 8.19 g/t gold. This demonstrated both processing viability and concentrate marketability within the district.

Second, bulk sampling allows grade reconciliation between drill-hole estimates and actual mined material. The Plomosas Mine resource currently totals 5 Mt Indicated at 54 g/t silver, 0.46 g/t gold, 1.0% lead, and 1.2% zinc (31 Moz AgEq) in the underground category, with an additional 3 Mt Inferred at 46 g/t silver (17 Moz AgEq). By systematically sampling the 21 accessible underground areas, GR Silver Mining can refine geological models and identify higher-grade domains that may support selective mining scenarios.

Fonseca elaborated on the engineering implications:

"The Company is also progressing process design criteria that will be the basis of preliminary flowsheet design and initial engineering and costing studies. This includes the development of technical specifications that will be the basis for process equipment selection. In conjunction with the assessment of preliminary pilot plant configurations, initial costs for the process portion of BSTM will be developed."

The strategic rationale extends to capital efficiency rather than committing to full-scale plant construction before operational data exists, the phased approach allows the company to install a pilot processing facility on-site and iterate on flowsheet design using representative mineralization.

San Marcial Discovery: Resource Expansion Drilling Underway

While Plomosas Mine provides near-term development potential, the San Marcial Area represents the company's primary exploration upside. The zone currently hosts 10 Mt Indicated at 148 g/t silver, 0.04 g/t gold, 0.2% lead, and 0.3% zinc (52 Moz AgEq) plus 3 Mt Inferred at 145 g/t silver (16 Moz AgEq) in shallow open-pit and underground scenarios. Drilling in 2025 has focused on step-out holes testing extensions of the main mineralized corridor and parallel structures identified through IP geophysics.

Results released during July-September 2025 included hole SMS25-09, which intersected 75 meters at 260 g/t AgEq starting at 520-meter depth, confirming mineralization extends at least 100 meters beyond the current resource shell. The intercept displayed chlorite-hematite alteration characteristic of intermediate-sulfidation epithermal systems, with boiling textures suggesting proximity to higher-grade feeder structures. Subsequent holes SMS25-10A and SMS25-08 targeted structural offsets and successfully encountered gold-rich intervals, including 9 meters at 374 g/t AgEq with elevated tungsten and copper values.

The company's geological model interprets the San Marcial resource as the upper portion of a much larger hydrothermal system hosted along the contact between volcanic sedimentary rocks and a regional porphyry intrusive center. Approximately 80% of the coincident chargeability geophysical anomaly remains untested by drilling, representing significant exploration potential within the project's 7,823-hectare land package. A 46-hole permit for Phase 2 drilling was granted in September 2025, supporting approximately 15,000 meters of additional drilling through year-end 2026.

Current Activities: Engineering, Permitting, & Resource Update Timeline

GR Silver Mining has completed a detailed laser survey of the Plomosas Mine's 7.4 kilometers of accessible underground development, providing precise spatial data for mine planning and ventilation design. This survey work supports the company's targeting of bulk mineable stopes where historical mining left ore in place. The areas selected for Phases I and II of the sampling program host continuous unmined zones with grades considered attractive for selective mining using mechanized methods.

The company is reviewing opportunities to integrate existing processing facilities within the surrounding Plomosas district into its BSTM framework. This could reduce capital requirements by utilizing toll milling arrangements rather than constructing dedicated processing infrastructure. Concurrently, metallurgical test work on representative samples is underway.

‍Fonseca noted:

"Additional metallurgical test work on representative samples collected from the historic mine are also being completed to corroborate previous test work that showed strong recoveries of silver, gold, lead, and zinc."

referencing historical recovery rates of 74% silver, 86% gold, 69% lead, and 75% zinc from the Plomosas sulfide mineralization.

Looking ahead, GR Silver Mining targets a resource update and preliminary economic assessment in 2026. This timeline allows incorporation of ongoing drilling results from San Marcial, underground sampling data from Plomosas, and metallurgical confirmation from bulk sample processing. The company also announced leadership transitions in October, with CFO Robert Payment assuming additional Corporate Secretary responsibilities and the departure of VP Operations Alejandro Cano as the BSTM program ramps toward implementation.

Financial Position & Capital Structure

As of September 30, 2025, GR Silver Mining held CAD$13.0 million in cash with no debt, providing a 15-month operating runway under current expenditure rates. The company's capital structure includes 430 million shares outstanding, 90 million warrants at an average exercise price of CAD$0.19, and 10 million options at CAD$0.26. Institutional and high-net-worth ownership comprises approximately 18% of the share base, with management and insiders holding 3%.

The company achieved significant trading liquidity during June-September 2025, ranking among the top 10 volume traders on the TSX Venture Exchange with average daily turnover of 7.6 million shares. This liquidity improvement accompanied share price appreciation of 92% year-to-date through September, outperforming the Global X Silver Miners ETF's 102% gain during the same period. The increased trading activity reflects growing investor recognition of the company's dual-track development and exploration strategy.

GR Silver Mining's current market valuation of CAD$146 million translates to approximately $1.09 per AgEq ounce against its 134 Moz total resource base. This compares to peer valuations ranging $2-4 per ounce for advanced-stage silver developers in Mexico, suggesting potential re-rating opportunity as the company advances resource definition and demonstrates bulk sampling economics. The company has not indicated plans for near-term equity financing, with existing treasury sufficient to execute planned drilling and engineering activities through 2026.

GR Silver Mining's investment case rests on multiple near-term catalysts that could drive valuation re-rating ahead of broader silver sector movements. The progression of bulk sampling from engineering study to on-site pilot processing in early 2026 will provide critical operational data and potentially early cash flow to self-fund ongoing development. Simultaneously, aggressive step-out drilling at San Marcial targeting the 80% untested portion of the geophysical anomaly offers resource expansion potential that could materially increase the company's metal inventory.

The company operates in a favorable jurisdiction with established mining infrastructure, skilled labor availability, and demonstrated permitting success for historical operations. Mexico's silver mining sector has attracted sustained major and mid-tier producer interest, as evidenced by recent M&A activity and ongoing consolidation among district-scale asset holders. GR Silver Mining's control of both a permitted historical mine and a growing open-pit resource positions it as a potential consolidation target or strategic partner as silver prices test multi-year highs.

For investors evaluating silver mining equities, GR Silver Mining offers leveraged exposure to metal price appreciation through resource growth and development de-risking, rather than dependence on single-mine operational execution. The company's fully funded treasury eliminates near-term dilution risk, while its management team's track record in project advancement and M&A execution provides credibility for value realization. As silver navigates its cross-currents between industrial demand and safe-haven flows, developers demonstrating operational progress and resource expansion can capture valuation premiums relative to exploration-stage peers.

The Investment Thesis for Silver Development Equities

• Diversify into mid-cap developers if silver sustains above $48/oz and macro volatility elevates safe-haven premiums.
• Prioritize companies with permitted infrastructure and cash resources sufficient to reach production decision without dilutive financing.
• Target jurisdictions with established mining districts where processing infrastructure and skilled labor reduce capital intensity and execution risk.
• Monitor resource conversion rates from Inferred to Indicated categories as validation of geological models and drilling effectiveness.
• Evaluate bulk sampling programs as critical de-risking milestones that validate metallurgy, grade reconciliation, and concentrate marketability ahead of feasibility studies.

GR Silver Mining's investment case rests on multiple near-term catalysts that could drive valuation re-rating ahead of broader silver sector movements. The progression of bulk sampling from engineering study to on-site pilot processing in early 2026 will provide critical operational data and potentially early cash flow to self-fund ongoing development. Simultaneously, aggressive step-out drilling at San Marcial targeting the 80% untested portion of the geophysical anomaly offers resource expansion potential that could materially increase the company's metal inventory.

The company operates in a favorable jurisdiction with established mining infrastructure, skilled labor availability, and demonstrated permitting success for historical operations. Mexico's silver mining sector has attracted sustained major and mid-tier producer interest, as evidenced by recent M&A activity and ongoing consolidation among district-scale asset holders. GR Silver Mining's control of both a permitted historical mine and a growing open-pit resource positions it as a potential consolidation target or strategic partner as silver prices test multi-year highs.

For investors evaluating silver mining equities, GR Silver Mining offers leveraged exposure to metal price appreciation through resource growth and development de-risking, rather than dependence on single-mine operational execution. The company's fully funded treasury eliminates near-term dilution risk, while its management team's track record in project advancement and M&A execution provides credibility for value realization. As silver navigates its cross-currents between industrial demand and safe-haven flows, developers demonstrating operational progress and resource expansion can capture valuation premiums relative to exploration-stage peers.

TL;DR

GR Silver Mining's Phase II underground sampling at Plomosas returned intercepts up to 2,365 g/t AgEq while advancing bulk test mining across 21 accessible areas. With CAD$13.8M in treasury, the company is drilling San Marcial's largely untested geophysical anomaly and targeting a 2026 resource update and PEA. Current valuation of $1.09/AgEq oz offers potential re-rating as development milestones de-risk the 134 Moz resource base in Mexico's established Rosario District.

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