Chile’s state-owned copper producer Codelco has suspended processing operations at its Andina division following a tailings spill that may have reached the Blanco River in the central Valparaíso region, prompting precautionary measures to protect drinking water supplies.
The company said Thursday that an obstruction was detected early in the morning in its tailings transport system near the Rápido RV4 sector, within the mountainous Río Blanco canyon. Codelco said an object may have fallen into the channel, causing a partial release of tailings that could have entered the river.
“In response to this situation, all emergency protocols were immediately activated,” Codelco said in a statement.
The measures included shutting down the concentrator plant, suspending tailings transport, diverting water to the Piuquenitos reservoir and conducting continuous river monitoring and water quality analyses.
The incident raises concerns about potential contamination of waterways connected to the Aconcagua River basin, a critical source of water for communities in central Chile. The extent of any downstream environmental impact has yet to be established.
Codelco said the situation was under control, mitigation efforts were continuing and the relevant authorities had been notified.
“We want to reassure residents that all necessary actions are being taken to protect the environment and to continuously monitor the situation,” the company said.
Andina, one of Codelco’s major copper operations, combines underground mining at Río Blanco with open-pit mining at Sur Sur —also known as the South pit— to produce copper and molybdenum. The company has not indicated when processing operations might resume.
The spill came on the same day Codelco disclosed that artificially inflated production figures in its reports amounted to 42,100 tonnes of copper.
Codelco’s inflated copper output scandal hits 42,100 tonnes
Board chairman Bernardo Fontaine told an extraordinary shareholders’ meeting that a separate reporting discrepancy involved 17,000 tonnes of copper inventory, valued at between $120 million and $140 million.
Chilean water utility Esval closed its surface water intake from the Aconcagua River as a precaution, activating underground water sources and backup systems to maintain drinking water production in Los Andes. The company said it was monitoring water conditions and coordinating with Codelco and local authorities.
Additional sampling is underway to assess potential contamination and determine whether further protective measures are necessary.
The precautionary shutdown highlights the potential consequences of mining-related incidents for communities that depend on river systems shared with industrial operations.
Environmental scrutiny
Chilean lawmaker Francisca Bello of the Broad Front coalition called for an investigation into the cause of the spill and its potential environmental consequences.
Bello said the incident had forced the immediate preventive closure of water control gates along the upper Aconcagua River, raising concerns about the security of local water supplies.
“We’re talking about the water supply for hundreds of families and communities,” Bello wrote on social media.
Bello urged authorities to establish the origin of the release, assess its downstream effects and provide timely information to affected communities.
“Water is life, and its protection cannot be left to the mercy of uncertainty,” Bello said.
The incident puts renewed attention on tailings management at Chile’s copper mines, where operations in mountainous terrain can intersect with river systems supplying nearby communities.
Further water quality testing and the results of Codelco’s investigation will help determine the environmental consequences of the spill and the conditions under which Andina can safely restart processing.