Zacatecas Silver completes sampling program at Oso Negro, Sonora

VANCOUVER, British Columbia, April 16, 2026 (GLOBE NEWSWIRE) -- Zacatecas Silver Corp. (TSXV: ZAC | OTCQB: ZCTSF | FRA: 7TV) (“Zacatecas Silver” or the “Company”) is pleased to announce the successful completion of its initial rock-chip sampling program at the Oso Negro project, located in Sonora, Mexico. The program was completed in March 2026 over the course of five days and samples have been dispatched to ALS for analysis with an expected turn-around of four to six weeks. One hundred and fifty-six rock-chip grab samples were taken from 3 out-cropping low sulphidation veins with cumulative strike length of over 2 km.

Veins are up to 3 m wide, multiphase with common veins breccias and pervasive iron oxides after sulphides. Quartz and vein textures are typical of the uppermost levels of a low sulphidation system, indicating that if present, the boiling and thus precious metal mineralization will be preserved below. Figure 1: Typical outcrop of brecciated low sulphidation quartz veins at Oso Negro showing pervasive iron oxide staining after sulphides.

All rock chip samples were cut prior to submission to ALS and a reference sample retained. Cut slabs show that veins are highly brecciated veins, with abundant limonite and hematite after sulphides, and dark grey goethite a secondary precipitate in fractures (Figures 2 and 3). The presence of these iron oxides is consistent with oxidation of sulphides.

Silicified fragments of wall-rock and vein are locally pervasively altered to limonite (Figure 4). Quartz is typically chalcedonic to finely saccharoidal consistent (Figure 4), with local bladed pseudomorphs (Figure 6), indicative of deposition above the boiling zone. Quartz may be locally dark grey and sulphidic.

Secondary silver minerals were noted in some samples (Figure 7). The rock chip sampling has demonstrated a robust low sulphidation vein system, characterized by over two strike kilometers of multiphase, brecciated, iron-oxide stained and infilled, upper level veins. Figure 2: Fractures vein comprising clasts of saccharoidal quartz, in part grey and sulphidic, with hematite and goethite fracture fill.

Figure 3: Fractures chalcedonic and fine saccharoidal quartz vein, with goethite fracture fill and boxwork. The upper red tuff is silicified and hematite stained wall rock. Figure 4: Pervasively limonite altered rock with iron-oxide boxwork after sulphide, chalcedonic quartz flooding and thin grey sulphidic quartz veinlets.

Figure 5: Pervasively silicified and fractures fragments of tuffaceous wallrock, with hematite and goethite fracture fill, forming part of a saccharoidal quartz vein which is partly dark grey and sulphidic. Figure 6: Whist bladed quartz pseudomorphs after bladed calcite indicative of the uppermost levels of a low sulphidation vein. Figure 7: Saccharoidal quartz vein with silicified and iron oxide-stained wall rock fragments.

Note flecks of dark grey, lustrous, secondary silver minerals. Oso Negro represents a high-priority, undrilled exploration target within a historic mining district known for high-grade precious metal mineralization. Historical channel sampling completed by previous operators returned significant grades, including 5.15 g/t Au and 953 g/t Ag over 1.2 metres, and 2.55 g/t Au and 346 g/t Ag over 1.8 metres (see news release dated June 3, 2021 of Heliostar), highlighting the strength and consistency of mineralization along strike.

CEO Comment Eric Vanderleeuw, CEO of Zacatecas Silver, commented: “Oso Negro is exactly why we pursued the acquisition of the Heliostar portfolio. Our strategy was to secure a pipeline of high-impact, underexplored assets in proven mining districts that could deliver near-term discovery potential alongside longer-term optionality. Oso Negro immediately stood out as a priority: it is undrilled, hosts multiple high-grade vein systems, and shows clear indications of a robust epithermal system with significant depth potential.

This initial mapping and sampling program is the first step in systematically advancing the portfolio, starting with our highest-conviction target. As we integrate results, we expect to rapidly define drill targets at Oso Negro while continuing to unlock value across the broader portfolio. The acquisition has transformed Zacatecas Silver into a multi-asset exploration company with the ability to generate consistent news flow and multiple discovery opportunities in parallel with our two existing resources with Esperanza and our Zacatecas Silver Project.” About Zacatecas Silver Corp. The Company has two key projects: the Zacatecas Silver Project in Zacatecas State, Mexico, and The Esperanza Gold Project in Morelos State, Mexico.

The Zacatecas Silver Project is located in Zacatecas state, Mexico, within the highly prospective Fresnillo silver belt, which has produced over 6.2 billion ounces of silver. The Company holds 7,826 hectares (19,338 acres) of ground that is highly prospective for low-sulphidation and intermediate-sulphidation silver base metal mineralization and potentially low-sulphidation gold-dominant mineralization. The Company announced an increase in silver resource at the Panuco South and North underground Mineral Resource Estimate now consisting of 3.41 million tonnes at 187 g/t AgEq (173 g/t Ag and 0.18 g/t Au) for 20.5 million ounces AgEq (19.0 million ounces silver and 19.2 thousand ounces gold) (see news release dated May 31, 2023).

The silver property is 25 kilometres (km) southeast of MAG Silver Corp.'s Juanicipio Mine and Fresnillo PLC's Fresnillo Mine. The Property shares common boundaries with former Pan American Silver Corp., now Defiance Silver claims and El Orito, which is owned by Endeavour Silver. Esperanza is an advanced stage, attractive low-cost, low-capital-intensity and low-technical-risk growth project located in Morelos state, Mexico.

Alamos has progressed the project through advanced engineering, including metallurgical work, while also focusing on stakeholder engagement, including building community relations. The Company announced a Mineral Resource Estimate at Esperanza consisting of a Measured and Indicated Mineral Resource Estimate of 30.5 million tonnes at 0.97 g/t AuEq for 956 thousand ounces AuEq and an Inferred Mineral Resource estimate of 8.7 million tonnes at 0.98 g/t AuEq for 277 thousand ounces AuEq (see news release dated November 16, 2022). Qualified Person The technical information in this news release has been reviewed and approved by Chris Wilson, B.Sc. (Hons), PhD, FAusIMM (CP), FSEG, FGS, Chief Geologist of Zacatecas Silver.

Dr. Wilson is a Qualified Person as defined by NI 43-101 and is not independent due being Chief Geologist and a Director. On behalf of the Company Eric Vanderleeuw Chief Executive Officer and Director (519) 729 2440 Forward-Looking Statements Information set forth in this news release contains forward-looking statements that are based on assumptions as of the date of this news release. These statements reflect management’s current estimates, beliefs, intentions and expectations.

They are not guarantees of future performance. Zacatecas Silver cautions that all forward-looking statements are inherently uncertain and that actual performance may be affected by many material factors, many of which are beyond their respective control. Such factors include, among other things: risks and uncertainties relating to Zacatecas Silver’s limited operating history, its proposed exploration and development activities on is Zacatecas Properties and the need to comply with environmental and governmental regulations.

Accordingly, actual and future events, conditions and results may differ materially from the estimates, beliefs, intentions and expectations expressed or implied in the forward-looking information. Except as required under applicable securities legislation, Zacatecas Silver does not undertake to publicly update or revise forward-looking information. Neither TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the policies of the Exchange) accepts responsibility for the adequacy or accuracy of this release.

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