Candles burn at a vigil for the workers at the El Teniente mine at the Los Maitenes access control in Rancagua, Chile, on August 2. Six miners died after an earthquake two days earlier caused a partial collapse at the world’s largest underground copper mine. Photo by Elvis Gonzalez/EPA
Chile’s El Teniente division — the world’s largest underground copper mine and operated by the state-owned National Copper Corp. — has partially resumed operations after a collapse that killed six miners and forced a halt to production.
The mine accounts for about 25% of Codelco’s production, has more than 2,800 miles of underground tunnels and produced 392,000 tons of refined copper in 2024.
On July 31, a magnitude-4.2 earthquake triggered a collapse that damaged 2.3 miles of interior tunnels, prompting the National Geology and Mining Service, Sernageomin, to order a suspension of operations for safety reasons. It was the worst incident 35 years.
“Each day of closure costs between 800 and 900 metric tons [880 to 992 U.S. tons] of refined copper, which, at current market prices, translates into daily losses of about $8 million,” said Víctor Pérez, a professor of sustainable mining at Chile’s Adolfo Ibáñez University.
He added that the mine will take several months to return to normal production.
Preliminary studies warned that losses could reach $70 million, in addition to about $100 million in repair costs. Estimates also project a future financial impact from delayed production of up to $30 million in present value.
“It is very likely that the losses will far exceed the initial estimates. The largest losses will be seen starting next year,” Pérez said.
El Teniente had forecast production of about 340,000 tons of refined copper this year.
“The suspension of operations will have repercussions. Codelco will have to review how to meet the target, but that will be difficult given the operational limits already set in a predefined extraction and processing plan,” said economist Christian Jiménez, director of Bold Economics.
Codelco is investigating the origin of the earthquake, as it is unclear whether it was caused by natural tectonic activity or induced by mining operations, such as drilling or rock bursts.
Analysts say that in the medium term, the company is expected to expand its use of technology to improve seismic monitoring and increase remote operations in high-risk areas.
Codelco is the world’s largest copper producer, responsible for about 7% of global output and holding roughly 30% of the world’s known reserves of the metal.
In 2024, it produced about 1.6 million tons of refined copper, supplying key industries such as electric power, automotive manufacturing and renewable energy, for which copper is essential for electric vehicles, transmission networks and clean technologies.
