Codelco Andina tailings spill: incident and water-risk lessons for engineers
Reviewed by Joe Ashwell

First reported on MINING.com
30 Second Briefing
Codelco has halted processing at its Andina copper division after an obstruction in the tailings transport system near the Rápido RV4 sector caused a partial tailings release that may have entered the Blanco River within the Río Blanco canyon, upstream of the Aconcagua River basin. Emergency actions include shutting the concentrator, suspending tailings transport, diverting flows to the Piuquenitos reservoir, and continuous river sampling, while water utility Esval has closed its Aconcagua surface intake and switched to underground sources for Los Andes. The incident coincides with disclosure of 42,100 tonnes of previously inflated copper output and a 17,000‑tonne inventory reporting discrepancy, intensifying regulatory and community scrutiny of tailings and water-risk management at Andina.
Technical Brief
- Obstruction in the tailings transport channel near Rápido RV4, likely from a fallen object, triggered the partial release.
- Codelco reports immediate activation of internal emergency protocols, including process isolation and notification of competent authorities.
- Piuquenitos reservoir is being used as a temporary hydraulic sink to divert and attenuate potentially contaminated flows.
- Esval closed Aconcagua surface intakes and switched to underground sources and backup systems to maintain potable supply resilience.
- Political response includes calls for a formal investigation into spill origin, transport pathway and downstream ecological impacts.
Our Take
Codelco already features heavily in our 24 Hazards stories, and the Andina tailings incident adds to a pattern of recent safety and governance pressure that also includes the Radomiro Tomic fatality and the late-October dismissals of senior staff across several divisions.
The involvement of Esval and the Aconcagua River in central Chile means this environmental event moves beyond a mine-site issue into regional water security, which in our database tends to trigger stricter permitting and monitoring conditions for subsequent tailings or pit expansions in the same basin.
Prepared by collating external sources, AI-assisted tools, and Geomechanics.io’s proprietary mining database, then reviewed for technical accuracy & edited by our geotechnical team.
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