Tailings dam decommissioning projects in Brazil: challenges, remote technologies and lessons learned

Vizcarra G.; Gonçalves T. · Proceedings of the International Conference on Mine Closure (2026) · DOI: 10.36487/acg_repo/2615_75

Resumen

Recent tailings dam failures in Brazil have driven regulatory reform and accelerated mandatory decommissioning of upstream-raised and facilities of uncertain construction method. Under the National Mining Agency (ANM) framework, strict access limits that constrain conventional investigations, monitoring and construction are imposed on high-risk (Level 3) dams. Consequently, projects increasingly deploy remote and unmanned technologies - robotic cone penetration testing with pore pressure measurement (CPTu) rigs for in situ characterisation, unmanned vehicles for earthworks and lift line spider systems for controlled personnel access, supported by real-time instrumentation to track geotechnical behaviour during closure. This paper summarises Brazilian experience with 3 decommissioning strategies: full tailings removal, partial removal and downstream buttress construction, selected according to geometry, emergency level, access and environmental constraints. Preventing liquefaction during earthworks emerged as a primary challenge; vibration surveillance systems were implemented to monitor equipment-induced ground motions, define trigger action response plan (TARP) thresholds and inform operational controls. The study distils practical lessons and outlines transferable approaches to improve safety and efficiency in tailings dam decommissioning internationally.