Triassic-Jurassic to Early Cretaceous volcano sedimentary sequences in the Sierra Madre del Sur are host to several VMS deposits and prospects, mainly in Guerrero and Mexico State, although the prospective sequences are more widespread, and the mineralization is commonly Late Jurassic to Early Cretaceous. Three of those deposits have resources published.
Campo Morado in Guerrero host the most resources, although not for a giant margin, with over 1.3 M Oz Au, 106 M Oz Ag, 613 M Lb Cu, 561 M Lb Pb and over 2.5 B Lb Zn. Tizapa and Rey de Plata have very similar resources for gold (600 K Oz Au), silver (70 M Oz Ag), lead (300 M Lb Pb) and Zinc 1,3 B Lb Zn), although Rey de Plata hosts five times as much copper as Tizapa. Campo Morado was mothballed by Nyrstar due to low metal prices and unresolved security issues, while Tizapa is in production and Rey de Plata in development, the two last both owned by Peñoles. As can be seen in the next table, VMS deposits in the Sierra Madre del Sur have an average size of 20 Million tons @ 1.4 g/t Au, 150 g/t Ag, 0.7 % Cu and 5% Pb-Zn combined.
The numbers we manage are largely from technical reports, company’s websites or yearly filings to the stock exchange, most to the end of 2014.
In the picture above, stream sediment sampling in Jayacatlan, Oaxaca, by Ricardo Ramonett. To get that sample we had to hike down 400 m of elevation, and then up again, under intermittent rain. One of the best and more tiring days of my life.