A new spoil tip is required to ensure the long-term operation of the Andina Mine, one of the largest copper mines in Chile. Engineers from GEOTEST Ltd have investigated the rock glaciers and permafrost in the area of the mine between 3000 and 5000 m a.s.l. and have written the corresponding chapter of the environmental impact assessment.
The Andina mine of the Chilean national mining company Codelco is one of the largest copper mines in Chile. In order to ensure long-term mining under modern criteria, modification of the open-pit mine and formation of a new spoil tip will be necessary. The so-called sterile material – i.e. material that is not suitable for mining but which has been extracted – will be deposited on the spoil tip. This should all take place outside a safety zone around the rock glaciers, which are among the most important drinking water reserves in semi-arid central Chile.
GEOTEST Ltd and its associate company Geotest Chile SpA, based in Santiago de Chile, were commissioned by Codelco to scientifically investigate the surrounding rock glaciers and to prepare data for the environmental impact assessment (EIA). Several months of fieldwork were required for the necessary mapping, probing and geophysical investigations. The working conditions in complex mine operations at 4000 m a.s.l. presented the 15-person field team with an exceptional logistical and physical challenge.
In cooperation with the permafrost research group led by Prof. Dr. Martin Hölzle at the University of Fribourg, we were ultimately able to produce a realistic estimate of the rock glaciers’ water contribution to mountain hydrology. Geophysicists from GEOTEST measured various hybrid seismic and geoelectric profiles, which served as a basis for determining the thickness of the rock glaciers and their ice content. Local meteorological data were also incorporated into the modelling.
In November 2019 Codelco finally secured an environmental permit, allowing construction work on the spoil tip to begin. This task will require the employment of 450 people for 36 months.
High-resolution seismic and geoelectric measurements provide information about the composition of the subsoil.