The playbook — gold · September 10, 2026
Oso Negro maps past 3 km of veins on surface — no drill hole yet
Zacatecas Silver's rock-chip campaign returns up to 20.3 g/t gold and 3,480 g/t silver, but the whole system is still untested by the drill.
On September 10, 2026, Zacatecas Silver said its second round of surface sampling at Oso Negro — a gold-and-silver vein project in Sonora, Mexico — returned rock chips grading up to 20.3 grams of gold per tonne (about two-thirds of an ounce in a tonne of rock) and 3,480 grams of silver per tonne. Mapping now traces more than 3 kilometres of veins across the property, and the company reports continuity along the full 600-metre Prospecto strike.
Here is the mechanism, and its limit. These are grab and rock-chip samples — bits of rock picked up at surface. A geologist choosing samples naturally reaches for the good-looking stuff, so a single high number does not tell you the average grade, and it cannot be turned into a gram-meter figure the way a drill hole can. What carries more weight than any one assay is the spread: 63 of 354 Phase Two samples ran between 1 and 20.3 g/t gold, and the grade tenor edged above Phase One. The surface textures fit the top of a low-sulphidation epithermal system — the kind where the richer ‘boiling zone’ can sit lower down, untested. This work defines drill targets. It does not define tonnes. The Qualified Person, Dr. Chris Wilson, is Chief Geologist and a director, and the company discloses he is not independent. Samples went to ALS Zacatecas with reference materials, blanks and duplicates inserted for quality control.
The caveats matter here. The whole system is undrilled — no intercepts, no confirmed continuity at depth. The boiling zone is inferred from surface rock, not tested. Veins are mapped ‘up to 3 metres wide,’ but that is a surface observation, not a true-width drill intercept, and no cut-off grade or compositing method is stated. Against a strong backdrop for junior gold — the GDXJ index climbed 22.8% and gold rose 6.2% over the three months — ZAC fell 18.8%, a 41-point gap. The dossier’s peer comparison notes that a divergence of this magnitude may reflect company-specific factors — dilution risk, weak newsflow, or liquidity concerns — rather than sector sentiment alone, though the cause is not established. Upcoming company milestones: the company says a drill-program update is coming ‘shortly,’ with a maiden diamond program at Prospecto and Tere planned once permitting clears, and a Preliminary Economic Assessment ‘progressing’ at the separate Esperanza gold project.