Geotechnical challenges of the biggest mining project in Argentina

Author(s): 
Gonzalo Rellán, Iñaki García Mendive, Gastón Quaglia, Ariel Abad, Juan Natalio Figueroa and Alejo Sfriso
Date: 
Sunday, November 15, 2015
First presented: 
VIII South American Congress on Rocks Mechanics
Type: 
Article
Category: 
Geotechnical

Pascua-Lama is the first bi-national mining project in the world, located between 3800 and 5200m.a.s.l. on the borderline between Chile and Argentina. Pascua lies on the Chilean side, in Huasco Province in the Atacama region, while Lama lies on the Argentinean side, in the Iglesia department in San Juan province. The project is developed by Barrick Gold and consists of the open-pit mine of one of the world's largest gold and silver deposits, with more than fifteen million ounces of proven and probable gold reserves and six hundred and seventy-five million ounces of silver contained within the gold reserves, as of December 31st 2013 and official reports. The project is still in the construction stage. Future production will include open-pit extraction from Chilean and Argentinean sides, primary crushing in Pascua, transportation of crushed ore to Lama through a 4.0km-long underground tunnel, stockpiling, processing and final disposal at the tailings dam in Lama. Site lithology can be characterized as superficial alluvial or colluvial soils generally followed by a competent cemented granular stratum named ferricrete which lies on top of a highly resistant igneous bedrock, mainly andesite, diorite and dacite. The paper describes the design and construction of some of the excavations, foundations, slopes, fills, retaining walls, MSE walls and CLSM fills, and the challenges imposed by high altitude, steep landscape, extremely cold winter temperatures and the complexity of the construction site.

Feature Author

Alejo Oscar Sfriso

Alejo O. Sfriso is a Principal Engineer with 25 years of experience in geotechnical engineering for infrastructure and mining works. He is an expert in the application of numerical methods for geotechnical design and analysis. In addition to his activity at SRK, he is the Director of AOSA - Geotechnical Laboratory, Professor of Soil Mechanics and Geology of the University of Buenos Aires, Vice President for South America of the International Society of Soil Mechanics and Geotechnical Engineering for the period 2017 - 2021, former Professor of Geotechnics at the National University of La Plata and former President of the Argentinean Society of Geotechnical Engineering.

Principal Consultant
PhD, Civil Engineer
SRK Buenos Aires
SRK Latin America