The Atacama Desert of Northern Chile is one of the driest areas in the world. With a surface area of approximately 105.000 km2 and scarce rainfall that rarely exceeds 15 mm per year. This location is also one of the most important reserves of mineral resources on the planet, hosting significant reserves of copper (nearly 40% of world production and 30% world reserve), gold, silver, iron and among others, emplaced mainly in fractured volcanic rocks.
For ore extraction, excavation to depths of several hundreds of meters below the surface is required for both open-pit and underground mining, reaching the groundwater level in most of the mines in the region. Therefore, for safety and operational purposes, the extraction of the encountered groundwater is necessary. As in the Atacama, the recharge due to precipitation does not contribute to the water supply, the groundwater systems are characterized mainly by water storage and lateral recharge from rainfall in the Andean highlands; therefore, these systems can be considered as a non-renewable resource.
Until 2022, the Chilean Legislature allowed the free use of the groundwater pumped during mine dewatering in the production processes. However, since 2023, all mines are required to inform to the General Water Direction (DGA) the volume and location of the groundwater extractions, and the use of this resource is allowed only if the sustainability of the aquifers is not jeopardized.
Therefore, the recent Chilean legislature makes it critical to understand the nature of hydrogeological systems in the region, to determine the impact of mine operations on groundwater levels, water storage, and the possible loss of lateral recharge, that could affect vegetation or water rights downstream. This represents a paradigm shift in the historical relationship between mining and groundwater systems and an excellent opportunity for the development of more sustainable mining in the Atacama Desert, one of the largest copper resources on Earth.
