Atmospheric rivers and recent tailings storage facility failures in central Chile: a harbinger of climate change impacts on critical mineral supply

Mining is needed to produce the goods, infrastructure, and jobs that modern societies depend upon, as well as the metals and materials to facilitate the global transition to net zero carbon emissions. Enormous volumes of waste, known as tailings, are generated from industrial mining because the valuable commodities form only a small proportion of the extracted ore. Typically, tailings are wet slurries composed of particles and water that are commonly stored behind dammed impoundments known as tailings storage facilities (TSF) that are intended to hold them indefinitely. Tailings dams failure (TDF) occur repeatedly due to earthquakes, overtopping and weak foundations, among other mechanisms. Such failures can extend 10-100s km downstream with severe environmental, health and financial consequences. With the global surge in demand for critical minerals and metals, and a corresponding dramatic increase in mining, there is an urgent need to understand the spread of material downstream from tailings dam failures and the rate at which the environment recovers from this contamination, including after remediation, in order to improve prevention and response planning. This is especially pressing in heavily mined regions of the Andes, such as in Chile with over 800 TSF, where earthquakes and an increasing frequency of extreme rainfall events from climate change may present severe risks to many of these 'evermore' structures. Such an event occured on June 13th 2024 at a mine in the Chilean Andes, where extreme rainfall triggered the partial collapse of a TSF in a large copper mine complex, causing an unknown volume of tailings to be spilled downstream. This presents a short window of opportunity in which to measure contamination flows from an ongoing breach before repairs scheduled for December 2024, and to calibrate the river contamination recovery rates and spread from TDF and non-failed TSF in the watershed. While measurements are available from catastrophic failures, such as the Brazilian Brumhadinho disaster in 2019, partial failures such as the current emergency in Chile are more frequent and potentially a more widespread threat to the Andean environment. This ongoing incident is, we believe, typical of the increasing chronic threat to these structures from climate change, with severe and accumulating contamination affecting communities, agriculture, and ecosystems downstream. This event provides a unique opportunity to conduct geomorphological-geochemical-mineralogical data to establish the recovery and trajectory dynamics of rivers and floodplan sediment contamination caused by TSF failures in these kind of environments. By working with Chilean partners we aim to provide new data and analysis to guide improvements in responsible mining practices.