VANCOUVER, British Columbia, July 09, 2026 (GLOBE NEWSWIRE) — Zacatecas Silver Corp. (TSXV: ZAC | OTCQB: ZCTSF | FRA: 7TV) (“Zacatecas Silver” or the “Company”) is pleased to announce that a second phase of rock chip grab sampling and vein mapping has been completed at the Oso Negro project, located in Sonora, Mexico. The program was completed in the first week of July 2026 and samples have been cut for reference, photographed and dispatched to ALS for gold, silver and base metal analysis. The program follows a phase one rock chip sampling program at Oso Negro which returned up to 14.8 g/t Au and 2,340 g/t Ag across 156 samples (see June 9, 2026 News Release).
Geological mapping during phase two exploration identified additional vein extensions at both the Prospecto and Tere vein low sulphidation epithermal systems (Figures 1 and 2). The Prospecto vein system now comprises over 2.5 strike kilometres of mapped veins. The Tere vein comprises approximately 0.5 strike kilometres of mapped veins.
Three hundred and ninety-one rock-chip grab samples were collected primarily from vein outcrop at both systems. Veins are up to 3 m wide, multiphase, with common vein breccias and pervasive iron oxides after sulphides. The focus of this exploration phase was to fine tune the position of planned angled diamond drill targets. The Company has identified 20 drill pad locations and has completed ecological studies as a pre-requisite of applying to SEMARNAT for a drill permit. The Company will update on drill plans shortly.
Rock chip grab samples included pervasively silicified and oxidized tuffs with abundant hematite and goethite infilled fractures (Figure 3), hematite-stained, multiphase quartz veins with abundant boxwork hematite and goethite after sulphides (Figure 4), and saccharoidal quartz with blebby iron oxides (Figure 5). Multiphase, dark grey, sulphidic vein quartz, with silicified tuff fragments and hematite-goethite fracture infill (Figure 6), and massive, dark grey sulphidic vein quartz with blebs of pyrite, void-filling iron oxide boxworks after sulphides, and localized hematite-goethite bands (Figure 7) were also present.
Vein textures are typical of the uppermost levels of a low sulphidation epithermal system, where precious metal mineralization is commonly preserved in association with a boiling zone at depth. Phase one sampling indicated the presence of high gold and silver grades in outcropping vein samples. The phase two program has confirmed the presence of extensive sulphidic quartz veins. This has significant implications for exploration drilling, which will focus on near surface depth extensions through a large number of shallow angled holes.