Guillermo Calo is a very experienced leader, with more than 30 years in management and administration roles across Argentina, Chile, Peru, Paraguay and Uruguay. He is currently the Managing Director of Rincon lithium project in Argentina. Rincon is a large undeveloped lithium brine project located in the heart of the lithium triangle in the Salta Province of Argentina, an emerging hub for greenfield projects.

Before joining Rio Tinto, Guillermo was the Chief of Staff at Allkem Limited, a global lithium chemicals company. Prior to this, Guillermo was General Manager for Galaxy Resources in Argentina and Vice President of Galaxy Lithium (Sal de Vida) S.A, leading the lithium-brine project Sal De Vida, in the province of Catamarca.

Guillermo also spent more than a decade at Barrick Gold, including as Regional President of the South American Business United with responsibilities for copper and gold operations across Peru, Argentina and Chile including at Veladero, Lagunas Norte, Pierina and Zaldivar mines, as well as the Pascua-Lama and Cerro Casale projects. In July 2013, Guillermo was appointed Executive Director and President of Barrick subsidiaries in Argentina to manage the Veladero Gold-Silver mine, the suspension of the Pascua-Lama project and the exploration of the Alturas Project.