Two workers killed after slope incident at Chile's El Teniente copper mine

Two workers have died following a slope incident at the open-pit section of Chile's El Teniente copper mine, with operations in the affected area remaining suspended while authorities investigate the circumstances surrounding the accident.

The incident occurred shortly before 2:00 p.m. on October 11 in the southern open-pit area of the mine. Three workers associated with contractor operations were carrying out inspections and clearing snow-covered roads using a motor grader and truck when a mass movement struck the area. One worker was rescued, while two others became trapped and were later confirmed dead following search operations.

There remains some uncertainty over the precise nature of the failure. Codelco described the event as a "snow avalanche", while other reports referred to it as a landslide or mudslide. Heavy rainfall and adverse weather had affected central Chile at the time, and operations in the sector had reportedly already been suspended because of the conditions.

The distinction is important because snow avalanches, debris flows, mudslides and conventional slope failures involve different triggering mechanisms and material behaviour. In mountainous mining environments, however, these processes can interact. Intense rainfall or snowmelt can increase water content within surface materials, reduce soil strength, mobilise loose debris and create rapidly moving flows across access roads and working areas.

Following the deaths, Chile's National Geology and Mining Service, SERNAGEOMIN, activated its Crisis and Emergency Management Committee to review available information, coordinate the response and determine further measures. Investigative police and prosecutors also attended the site as part of the formal investigation.

SERNAGEOMIN's preliminary observations have already placed particular emphasis on assessing natural hazards outside normal mining operations. The regulator highlighted the need for better evaluation of areas exposed to avalanches, landslides, mudflows, rockfalls and interference with natural drainage, particularly where changing weather conditions can alter slope behaviour within a short period.

The incident also underlines the importance of access control during adverse conditions. Roads, inspection routes and maintenance areas can remain exposed to slope hazards even when main production activities are suspended. Weather thresholds, terrain monitoring and clearly defined exclusion zones therefore become critical where workers may still need to enter an area for inspections, clearing or emergency works.

El Teniente, located around 75 km southeast of Santiago, includes both open-pit and extensive underground operations. The mine has already faced significant ground-related safety challenges in recent years. In July 2025, six workers were killed following a rockburst associated with a magnitude 4.2 seismic event in the underground mine. Development at the Andes Norte underground expansion was also suspended in August 2026 after elevated seismic risks were identified.

The latest fatalities involve a different type of hazard, but they reinforce the complexity of managing ground behaviour across a mine that combines steep mountainous terrain, severe weather, open-pit slopes and deep underground excavations. Investigations now under way will need to establish the exact failure mechanism and whether the existing weather and slope-risk controls were adequate for the conditions present on October 11.