Zacatecas Silver Corp. has returned assay results from the second phase of rock chip sampling at its Oso Negro project in Sonora, Mexico, highlighted by individual grab samples grading up to 20.3 grams per tonne gold and 3,480 grams per tonne silver.

The second program comprised 354 samples, bringing the project total to 510 rock chips. Of the latest batch, 63 samples assayed between 1 gram per tonne and 20.3 grams per tonne gold, while 58 samples returned between 100 grams per tonne and 3,480 grams per tonne silver. An additional 20 samples yielded over 1% lead or zinc.

Mapping during the work extended the total strike length of the vein system to more than 3 kilometres, up from 2 kilometres reported after the initial program. Results confirmed that the Prospecto vein and its southeast splays are mineralized along their entire 600-metre mapped strike length.

The multiphase veins reach up to 3 metres in width and display textures and geochemical signatures typical of the uppermost levels of a low-sulphidation epithermal system. According to the company, these characteristics indicate that the boiling zone, which typically hosts the highest precious metal grades in such systems, may be preserved at depth.

Permitting and drill plan designs are currently underway to test the Prospecto and Tere vein systems with shallow, angled diamond drill holes. Zacatecas Silver previously closed an oversubscribed non-brokered private placement financing of C$3.75 million in September 2025 to fund its ongoing exploration and drill programs. Alongside Oso Negro, the company holds three other exploration properties in Sonora, including Cumaro and La Lola.

“Phase Two did two things for us at Oso Negro - it extended the system to over three kilometres of mapped veins, and it confirmed the Prospecto Vein carries gold and silver along its entire 600-metre strike,” said Eric Vanderleeuw, Chief Executive Officer and Director. “This is an undrilled system showing the surface signature of a preserved low sulphidation target, and Prospecto and Tere are where we want to start. With Cumaro advancing alongside it, Sonora is becoming a significant part of our story, and with our recent financing we have the means to advance it.”

— Eric Vanderleeuw, Chief Executive Officer and Director

Preparations for the upcoming drill programs continue across the company's portfolio as management advances both Sonora and its flagship Zacatecas projects.

Read the full announcement: Zacatecas Silver Expands Oso Negro to Over 3 Kilometres of Mapped Gold-Silver Veins; Phase Two Rock Chip Sampling Returns up to 20.3 g/t Gold and 3,480 g/t Silver