Mr. James Anderson reports

GUANAJUATO SILVER PROVIDES NEW MINERAL RESOURCE ESTIMATE FOR THE SAN IGNACIO MINE

As part of a scheduled program to update its National Instrument 43-101 technical reports and resource estimates for all of its producing mines in Mexico, Guanajuato Silver Company Ltd. has released a new mineral resource estimate (MRE) for Guanajuato Silver's 100-per-cent-owned San Ignacio mine located in Guanajuato, Mexico. The 2023 MRE was prepared by APEX Geoscience Ltd., with an effective date of Sept. 21, 2023. The resource update report will be filed under the company's SEDAR+ profile within 45 days of this news release, in accordance with disclosure and reporting requirement set forth in National Instrument 43-101. The 2023 MRE supersedes the historical mineral resource estimate for the San Ignacio mine, disclosed previously by the company in the technical report entitled "Technical report on the Valenciana mine complex, Guanajuato, Mexico," with an effective date of April 30, 2022.

James Anderson, chairman and chief executive officer, said: "The significant increase in the San Ignacio mineral resource across all categories can be attributed to the exceptional work on the part of our Mexican exploration teams -- their efforts over the past year have expanded our understanding of the mineralized systems in place at San Ignacio while returning consistently high-grade results, some of which are highlighted below, that have led to an increase of 130 per cent in the measured and indicated category, and 283 per cent in the inferred category."

Mr. Anderson added: "With this new resource estimate for San Ignacio, we are advancing the important work of upgrading all of our resource estimates for our four producing silver mines in Mexico. Because of the rapid pace of Guanajuato Silver's growth through our mine acquisition strategy, all of our mineral resources were originally categorized as historical. In June of this year, we presented a new preliminary economic assessment for our El Cubo mines complex (see Guanajuato Silver news release dated June 26, 2023 -- Guanajuato Silver provides updated PEA for the El Cubo mines complex). Upgrading all of our historical mineral resource estimates is a priority as this ensures our data is reliable and relevant, which is crucial for operational efficiency and strategic planning."

Selected 2023 San Ignacio drill results:

• Drill hole UGSI22-006 (Melladito vein) returned 4.92 metres true width of 1,219 grams per tonne (g/t) silver equivalent (AgEq), including 0.42 metre true width of 6,981 g/t AgEq (see Guanajuato Silver news release dated Feb. 23, 2023).
• Drill hole UGSI23-010 (Melladito vein) returned 4.89 m true width of 359 g/t AgEq;
• Drill hole UGSU23-009 (Purisima vein) returned 1.93 m true width of 516 g/t AgEq.

See the Guanajuato Silver news release dated May 18, 2023.

2023 mineral resource estimate

Mineralization at San Ignacio exists within quartz and calcite veins; four distinct mineralized domains exist at San Ignacio, characterized by four primary veins: Melladito, Intermedia, Nombre de Dios and the Purisima vein. In addition to reinterpreting the primary vein domains, the 2023 MRE includes mineralization from 22 additional vein domain models, contributing to the significant expansion of the San Ignacio mineral resources. The 2023 MRE is based on the newly constructed domain models, and uses drilling and underground channel sampling databases updated to July 11, 2023. The updated database now includes an additional 5,350 drill hole samples and 9,784 underground channel samples since the last MRE. The 2023 MRE has an effective date of Sept. 21, 2023.

The 2023 MRE comprises measured and indicated mineral resources of 7.621 million troy ounces (Moz) AgEq at 300 g/t AgEq within 790,000 tonnes (t), and inferred resources of 22.167 Moz AgEq at 318 g/t AgEq within 2.166 Mt (million tonnes). These figures represent increases in contained metals of approximately 4.318 Moz AgEq in the measured and indicated category (130-per-cent increase), and 16.385 Moz AgEq in the inferred category (283-per-cent increase) versus the previously reported historical resource estimate. The 2023 MRE for the San Ignacio mine is presented in the table entitled "2023 San Ignacio mineral resource estimate (effective date Sept. 21, 2023)."

Mineral resource estimate methodology

APEX personnel used ordinary kriging with locally varying anisotropy to estimate silver and gold grades in a three m by three m by three m parent block model. This model is subblocked to 0.5 m by 0.5 m by 0.5 m for stope optimization and resource reporting. Kriging considers capped drill hole and underground channel composites.

Three types of material were identified by APEX: In situ (unaffected by mining), modern remnant and historical remnant. A 3-D wireframe of modern workings, current to May 31, 2023, was used to exclude already-mined areas from the block model. Volumes within the estimation domains that lie in between and immediately next to modern stopes are categorized as remnant material. Historical mining areas, inactive and where the extent of mined areas is poorly constrained due to the age of the workings, were modelled utilizing a 40 m by 30 m by five m search ellipsoid and modern drilling data logged as backfill or stope. Material within the estimation domains close to the modelled historical workings is categorized as historical remnant material. In situ resources, detailed in this news release, exist above, below and along strike to current operations, and outside the modelled historical stopes. This release does not disclose the amount of modern remnant and historical remnant material, which remains under assessment for their resource potential.

For measured resources, blocks must be informed by three drill holes within a search ellipse with the size of 25 m by 25 m by 15 m, based primarily on the first variogram structure. For indicated resources, blocks require a minimum of three drill holes within a search ellipse measuring 45 m by 35 m by 15 m. For inferred resources, blocks need at least one drill hole within a search ellipse of 80 m by 50 m by 15 m, based primarily on the second variogram structure. As a final step, classification of resources within 10 m of channel composites are upgraded by one level of confidence (that is, inferred to indicated or indicated to measured). Because the channel samples are collected underground, where geologists can observe and verify the geological continuity of the mineralized material, this significantly increases confidence in the interpretation. This final classification step has a minor influence on the reported in situ resources, as the channel samples' influence is primarily limited to the modern remnant resource area.

Sampling and quality assurance/quality control

Company geologists inspected the received drill core and marked intervals for sampling. Using a diamond-blade saw, the core was split in half lengthwise. One-half stayed in the core box, while the other went into sealed plastic bags and assigned a unique sample number. Following company protocols, geologists inserted quality assurance/quality control (QA/QC) samples into the sample stream. The samples stayed securely on site until sent to the lab. The 2023 MRE calculation primarily relied on analytical work completed by SGS Mexico SA de CV in Durango, Mexico (SGS Durango), and, most recently, the local Cata laboratory in Guanajuato, Guanajuato, Mexico. SGS Durango is an ISO/IEC 17025 accredited laboratory independent of the company. SGS Mexico constructed the Cata laboratory in 2006 and maintained it until the beginning of 2019. After this, the company assumed management of the lab, removing its independence, which has since maintained SGS procedures and high-quality standards. Approximately 10 per cent of all analytical samples were sent to a certified independent laboratory for reanalysis and statistical comparison of assay values to validate the laboratory preparation procedures and analytical results.

The analytical process used involved crushing the core samples so that a minimum of 70 per cent of the material passed a two-millimetre mesh. After this, the material was pulverized such that 85 per cent of a 250-gram split passes a 75-micron mesh. Gold was analyzed using a 30 g fire assay preparation with an atomic absorption finish. Samples exceeding 10 g/t gold, or 300 g/t silver were reassayed utilizing a gravimetric finish. Following industry-standard procedures, blanks and certified reference material (standards) were inserted into the sample sequence and sent to the laboratory for analysis. A review of the QA/QC samples included statistical analysis to indicate whether the reference materials pass specific parameters for acceptance to ensure accurate and verifiable results. Guanajuato Silver detected no significant QA/QC issues during the data review and is unaware of any sampling, recovery or other factors that could materially affect the accuracy or reliability of the drilling data used to prepare the 2023 MRE.

About Guanajuato Silver Company Ltd.

Guanajuato Silver is a precious metal producer engaged in reactivating past-producing silver and gold mines in central Mexico. The company produces silver and gold concentrates from the El Cubo mine complex, the Valenciana mine complex and the San Ignacio mine; all three mines are located within the state of Guanajuato, which has an established 480-year mining history. Additionally, the company produces silver, gold, lead and zinc concentrates from the Topia mine in northwestern Durango. With four operating mines and three processing facilities, Guanajuato Silver is one of the fastest-growing silver producers in Mexico.

Technical information

Reynaldo Rivera, vice-president of exploration for Guanajuato Silver, has approved the scientific and technical information contained in this news release. Mr. Rivera is a member of the Australasian Institute of Mining and Metallurgy (AusIMM -- registration No. 220979) and a qualified person as defined by National Instrument 43-101 -- Standards of Disclosure for Mineral Projects.

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