History
According to legend, the El Teniente mine was discovered in the 1800s by a fugitive Spanish official. Exploitation of the resource began in 1819. The best ore was mined manually in what would be called the Fortuna sector, and transported out of the mine by pack animals, such as ponies and mules. It was worked until 1897, when the high-grade ore was exhausted.[9]
In 1904 William Braden (an engineer from New York City, United States)[10] and E.W. Nash formed the Braden Copper Company. They built a road for carts and a concentrating plant, which was in operation by 1906.[11][12]
In June 1910, Guggenheim Exploration took control of the mine and provided financing.[12] In 1916 Braden became a subsidiary company of Kennecott Copper Corporation,[13] which was based in Utah.
Chileans have referred to such large-scale copper mining operations as La Gran Minería del Cobre (a major copper mine). Before nationalization, these operations generated a large proportion of the foreign currency which the country received.
In 1945 there was a disaster at El Teniente mine, resulting in the deaths of 355 men and injury to 747 more. It was the largest mining accident in Chilean and has the highest death toll in world history associated with metal extraction. Some 1,000 miners were down in the pits when the fire started in a nearby warehouse. Dense smoke spread in the underground tunnels. Most of the dead and injured suffered carbon monoxide poisoning. Emergency exits were not well marked. In Chile, this incident is known locally as the Smoke Tragedy .[6]
In 1967 the Chilean government bought a 51% stake in the mine and founded Sociedad Minería El Teniente.[13] Under this agreement Kennecott built a new concentrator, and the mine expanded production to 63000 t per day.[11]
On July 11, 1971, President Salvador Allende ordered the Chilean nationalization of copper,[14] in an effort for the country to gain more benefit from the mines. Corporación Nacional del Cobre de Chile (known as Codelco) was formed, and El Teniente became a state-owned operation. The Chilean government paid Kennecott $92.9-million for the property.[15]
The mine increased production to 100000 t of ore per day,[11] and in 2006 the mine produced over 418000 t of copper.[16]
The Canadian company Amerigo produces both a copper and molybdenum concentrate from El Teniente's tailings. It has been granted the right also to treat higher grade tailings from a large, abandoned tailings impoundment near the El Teniente property.[17]
On 31 July 2025, a magnitude 4.2 earthquake, following a seismic tremor, caused a collapse at the mine.[18][19] A large scale rescue operation involving over 100 personnel, including experts from the 2010 Copiapó rescue, was launched.[19][20] On 2 August 2025, the final body was found bringing the death toll to 6, the regional prosecutor said the focus would now be on a criminal investigation in to the incident.[20]
