Climate Change impacts in Andean Mining risk management regarding torrential processes. Case Study at CODELCO ANDINA Division, Chile.

Copper mining activities in the Chilean Andes are located at elevations ranging from 2,500 to 5,000 meters above sea level (masl). These industrial operations significantly increase exposure to risks in these inhospitable areas, which are highly vulnerable to natural hazards. The CODELCO ANDINA mining facilities cover approximately 350 km² and encompassing several glaciers, mountain valleys and rivers. The most intense mineral extraction activities take place above 4,300 masl and continue uninterrupted during the winter (rainy season).

Traditionally, the primary geomorphologic hazards identified in these areas have been rockfalls, debris flows, and snow avalanches. However, in the past decade, new torrential hazards, such as debris floods and debris flows, have emerged. These new hazards are driven by climate change, particularly its relation to liquid precipitation. The 0°C isotherm, which marks the boundary between areas of liquid and solid precipitation, plays a critical role in these changes. As the isotherm rises, it expands the area of liquid precipitation, increasing runoff surfaces and, consequently, drainage network discharges. Extreme event analysis now requires careful monitoring of the correlation between rainfall intensity and the isotherm's location.

Additionally, CODELCO ANDINA is situated on the edge of permafrost regions. With the retreat of permafrost, large areas of cold-climate weathered material—ranging from silt to boulder-sized debris—are becoming erodible. The geomorphology of the landscape, traditionally classified as periglacial, is rapidly transitioning to fluvial due to climate change. This creates an "explosive cocktail" of high-mountain geomorphology, increased sediment availability, and increased water discharge.

Over the past 15 years, risk management plans have been developed and implemented. However, climate change necessitates a reformulation of these plans. In 2023, two extraordinary events occurred, one of which involved over 300 mm of liquid precipitation within 48 hours—an event entirely unexpected for this region.

These new conditions require updated risk management strategies. This study introduces new hazard assessments obtained by integrating observational meteorological data (1964–2023) with climate models (ERA5-Land reanalysis and CMIP5/CMIP6 ) to identify trends in temperature, precipitation, and extreme events. A combined modeling methodology was applied to characterize fluvial and torrential processes.