On March 28, 1965, an earthquake with its epicentre in Cabildo and La Ligua collapsed two tailings’ dams (earthen structures used to store liquid or near-liquid mining waste) at the El Soldado copper mine, killing more than 300 people and almost completely burying the town of El Cobre. It is one of the biggest mining tragedies in Chile and worldwide.
The El Soldado mine is in the Valparaíso region, in the El Melón mountain range, in the commune of El Melón, 125 km north of Santiago. In 1965, when the tragedy occurred, it was owned by the French company Sociedad Minera y Metalúrgica de Peñarroya, whose Chilean subsidiary was Disputada de Las Condes.
At 12:33 p.m., the tragedy struck.
A 7.6 magnitude earthquake on the Richter scale, with its epicentre in Cabildo and La Ligua, 30 kilometres from the town, caused the immediate collapse of the old tailings dam wall… as well as the new one, which had been recently built.
Everything began to shake violently, and a deafening noise filled the place. An avalanche of wet tailings, carrying rocks, debris, and zinc cans in its path, quickly began to bury everything…
The old tailings began to flow like enormous quicksand from which escape was impossible.
It is estimated the avalanche reached a volume of 10 million cubic meters, covering an area eight to ten kilometres long and between 200 and 500 meters wide. This landslide travelled fourteen kilometres, at a speed between 35 and 50 kilometres per hour.
Several other mining tailings dams in the Valparaíso Region collapsed in this earthquake: Los Maquis, Cerro Negro, Bellavista, La Africana, El Cerrado, and La Patagua. But none caused the damage and misfortune which took place at El Cobre.
In a matter of minutes, the mud lava buried the town’s 80 houses and took the lives of more than 300 people. To this day, there is no exact death toll. The lowest estimated death toll is 247. Since no record was kept of people entering and leaving the mining camp at the time, the estimated number of missing people ranges between 350 and 400.
President Frei Montalva arrived in an Army Apache helicopter to witness the full extent of the tragedy on the ground.
People came from all over to support the rescue: families of the victims, residents of other camps, firefighters, the Chilean Carabineros, Caritas, the Army, Boy Scouts, and the Red Cross, whose dog Dorobrando is said to have performed heroic work.
But they were only able to rescue 70 bodies.
Amid the screams, grief, and shock, family members, friends, and those who came to help organized a makeshift cemetery to bury and remember their dead. They buried them in coffins hastily assembled from pine planks, on which they painted large red letters that read «NN.»
The press of those fateful days referred to the town of El Cobre as «The Valley of Death.»
As time passed, survivors regularly came to leave flowers where their homes or loved ones might have been… in memory of their loved ones. Slowly, what had been the town was transformed into a cemetery.
Amidst the grief and pain, social measures began to be implemented to support the survivors: evacuation of the camps, emergency housing, food distribution, victim identification, civil procedures, investigation processes, etc.
In just under three months, a new camp was built, and the El Soldado mine resumed operations. Over the following years, the inhabitants of El Cobre were gradually resettled in the town of El Melón.
Father Gustavo Filippi Murato took care of 12 children orphaned by the earthquake: nine boys and three girls. “We must do things, not talk about them,” he said, quoted in “Los Hijos del Terremoto,” an article published in El Mercurio on January 8, 1984.
On March 28, 1966, for the first anniversary of the tragedy, and after a very emotional mass in the parish church—which was not destroyed—a monolith was unveiled in memory of what had happened. Thus, “El Parque Los Mineros” or “Miner’s Park” was officially born, “a cemetery that would give rest to those trapped by the sand,” writes José Díaz Pozo in “Desde Adentro.”
From then on, every March 28, a ceremony and a prayer service are held at El Parque Los Mineros in memory of the victims. This Friday the 28th, the 60th anniversary, this commemorative ritual will be repeated.
Before this tragedy, the legal regulations for the construction of tailings dams in the mining code were minimal. Following this tragedy, the Chilean government began a regulatory reform process regarding the construction and management of tailings dams.
In 1970, regulations for the foundation of tailings dams or dams were issued. Decree 86 established the application of improved technologies for the construction of these reservoirs and required mining companies to comply with these new regulations and standards for the construction and management of tailings dams.
«Environmental and social standards and regulations appear to be «In the wake of tragedies and the movements these events generate,» explained Nigel Wight, a researcher in the Social Performance and Resource Governance area of SMI-ICE-Chile, who is conducting research on the El Cobre tragedy.
«What happened 60 years ago in El Cobre shows us that a society’s collective memory is often very short. Just three decades earlier, in 1928, the Barahona dam disaster had claimed the lives of 55 people, and for the same reason: an earthquake caused a tailings dam to collapse. And this happened in less than a generation. Clearly, society doesn’t learn its lessons just from the pain of tragedy.» It also requires social organization and public policies to generate change.”
“Following the El Cobre tragedy, the construction of upstream dams was banned in Chile,” explained Nigel Wight. “However, over the years, the story faded from the national consciousness and memory, and its memory has only remained very much alive at the local level, as part of the social fabric of El Melón, among the people who experienced the disaster and their families.”
Despite its magnitude in terms of human losses, the El Cobre disaster 60 years ago did not have the social or environmental impact of the two major tailings disasters that occurred in the last decade: the Bento Rodrigues dam disaster in Mariana, Minas Gerais, in November 2015; and, later, the Brumadinho tragedy on January 25, 2019, which claimed the lives of 268 people when a dam collapsed. A mine shaft filled with wastewater from the Córrego de Feijão mine collapsed, spilling thousands of cubic meters of water and toxic mud onto the area.
The Brumadinho disaster sparked a global movement that achieved reparations and major regulatory changes. Following lawsuits against the mining company Vale, four years later the Global Industry Standard on Tailings Management (GISTM) was created, the most demanding and industry-validated standard currently in existence.
“In 1965, without social media and so much technology, it was more difficult to escalate a local tragedy to a national and then international level, as happened with Brumadinho,” explained Nigel Wight. “Today, technology and social media make it possible to maximize the impact of a social movement. After the El Cobre tragedy, local actors lacked the impetus or strength to have an impact beyond the local level. Most of the town was then working for the Disputada de Las Condes mining company, which operated the El Soldado mine, and the victims’ families were unable to organize in the months and years following the tragedy to initiate legal action against the company.
“Despite efforts by the mining industry to mitigate the risks associated with tailings dams, failures remain. In 2024, the Minera Las Cenizas tailings dam in Cabildo suffered a landslide at the tailing’s impoundment wall. A few days ago, in Potosí, Bolivia, a pile of mud containing mining waste left the town of Andavilque buried beneath the mud.” Shortly before, last February, a tailings dam burst with acidic waste in Zambia, contaminating approximately 100 kilometres of the Kafue River.
«Both Brumadinho and El Cobre were preventable tragedies, resulting in hundreds of victims attributable to human error,» said Nigel Wight. «Events like these ones lead to change. The El Cobre tragedy changed national regulations. And the global community’s rejection of Brumadinho led to the creation of GISTM.
“While these transformations have had a positive impact on tailings management, it is hoped that the necessary improvements will not be brought about solely by the occurrence of disasters, resulting in loss of life.”
Professor Deanna Kemp, of the Sustainable Minerals Institute at The University of Queensland, was part of the Global Tailings Review following the Brumadhino mine disaster in 2019. Following extensive consultation, the review panel drafted an unprecedented global standard on tailings management, applicable to existing and future tailings facilities called GISTM, and it was launched in August 2020.
Kemp explained the importance of considering a holistic approach to tailings management as a priority to prevent future disasters.
“GISTM aims to strengthen tailings management practices by integrating local social, environmental, economic, and technical considerations throughout the entire lifecycle of a facility, regardless of its location and of who operates it,” she said.
«The anniversary of the El Cobre tragedy makes us reflect on how much has changed in the last six decades and what still needs to change in the way the industry manages waste.»
