RANCAGUA, Chile, Aug 3, 2025 (BSS/AFP) - One of five miners trapped after a partial collapse at the world's largest underground copper mine has been found dead, Chile's state-owned Codelco group announced Saturday.

The collapse took place Thursday at the El Teniente mine in Rancagua, 100 kilometers (62 miles) south of Santiago, following a "seismic event."

It was not yet known whether the tremor was natural or caused by drilling.

At least 100 people were participating in the rescue operation for the workers, who had been extending the mine to a depth of 1,200 meters (3,900 feet).

"As part of the search operation, human remains were found and have yet to be identified by the authorities," Codelco said in a statement.

El Teniente general manager Andres Music said the discovery of the miner's remains "deeply saddens us, but it also tells us that we are in the right place" to find the other missing workers.

Thursday's magnitude 4.2 quake resulted in an initial toll of one dead and nine injured.

President Gabriel Boric visited miners' relatives on Saturday and vowed to "complete the search."

"Codelco has all the resources, experience and technology to carry out" the search, he said.

Work has been suspended at El Teniente, which began operating in the early 1900s and boasts more than 4,500 kilometers (2,800 miles) of underground tunnels.

Last year, the site produced 356,000 metric tonnes (over 392,000 tons) of copper -- nearly seven percent of the total for Chile.

Chile is the world's largest copper producer, responsible for nearly a quarter of global supply with about 5.3 million metric tonnes (5.8 million tons) in 2024.

The metal is critical for wiring, motors and renewable energy technology.