"Codelco collapse was likely caused by mining rather than nature", 07 August 2025

...The seismic event that caused a fatal collapse at Codelco’s biggest mine in Chile is likely to have been caused by mining activity rather than nature, according to a person with direct knowledge of the matter.

The probable scenario being used inside Codelco is that the incident was caused by geological stresses resulting from the project’s own extraction processes rather than any naturally occurring shifting of tectonic plates, the person said, asking not to be identified given an investigation is ongoing.

El Teniente, one of the world’s biggest underground copper mines, has been halted since July 31, when six workers died and nine others were injured following a 4.2-magnitude event that caused part of the operation to collapse. The tremor affected a newly developed area known as Andesita.

The accident has rocked the mining industry in Chile, where projects need to be built to withstand frequent and sometimes massive seismic activity. State-owned Codelco has filed a request to restart parts of the mine while it carries out an investigation into the cause of the incident...

To restart the mine, Codelco has to satisfy regulators and unions that the whole of the underground operation is stable, not only the affected areas. A comprehensive review of the mine’s current plans, particularly the design assumptions and safety criteria applied in all key zones will be needed...