The Tostado project consists of five concessions totalling approximately 1,500 ha located in Region II some 125 km southeast of Antofagasta. The project is approximately 12 km southwest and 8 km east-southeast of Yamana’s El Peñon and Fortuna mines respectively, and along strike from the principal veins reported at the Fortuna mine. A large hill, Cerro Largato, forms a north-south elongated outcrop of argillic altered and brecciated rhyolite that intrudes and is in fault contact with porphyritic andesitic units and dacitic to rhyodacitic units towards the east and southeast. These outcropping units are surrounded by gravel and caliche covered areas. Alteration is most intense along the breccia bodies that are spatially related with the dominant N-S and NW-SE structural trends. Associated with the argillic alteration and structural trends are variable intensities of hematite-jarosite bearing veinlets.
Previous work by SQM has included geological mapping and sampling, trenching, and approximately 1,937 m of reverse-circulation drilling in 17 holes. The results have confirmed the presence of structurally control silver-dominated mineralization, with highly anomalous levels of silver, arsenic and antimony and anomalous levels of lead and zinc. The best intercept from the previous drilling was 10.0 m at 247.6 g/t silver.