In the previous post it was established that intermediate sulphidation epithermal vein, stockworks and disseminated deposits are the most conspicuous mineralization style in the Altiplano Mexicano. However, there are some deposits with intermediate sulphidation epithermal affinity that deserve another classification, given their geological and size constraints. Some controversy is expected, because the economic importance these deposits have, and the overlapping nature of the limits with other mineralization styles.
The main characteristics of these deposits are that the bulk of mineralization is hosted in diatreme breccias, and the great size the deposits can attain, hundreds of millions of tons of polymetallic ore.
Three of those deposits have published resources (all included) for over 17.5M Oz Au, 1,568M Oz Ag, 11.5B Lb Pb and 24.4 B lb Zn. The two biggest deposits were discovered in early 2000 and are located in the central part of this region in the states of Zacatecas and Chihuahua.
Peñasquito´s Goldcorp in Zacatecas state, currently in production, has the biggest resource with 1.3 B tons at grades of 0.38 g/t Au, 25.5 g/t Ag, 0.26% Pb and 0.61% Zn. It is followed by Cordero of Levon Resources in Chihuahua state with 940.6 M tons at grades of 0.05 g/t Au, 17.6 g/t Ag, 0.24% Pb and 0.47% Zn. Finally, a smaller deposit discovered in this region is Km 66 in Durango state with 8.6M tons at grades of 0.01 g/t Au, 29.4 g/t Ag, 0.44% Pb and 1.06% Zn.
There are few prospects and projects in the Altiplano displaying the same mineralization style but they have not seen enough exploration work to delineate resources yet.
The table below shows tonnages, grades, as well as gold, silver, lead, and zinc resources (all inclusive) for each of these three deposits.