Minera Las Cenizas tailings spill disrupts water supply in Peñablanca

Approximately 700 residents of Peñablanca, located in the Cabildo commune of Chile's Valparaíso Region, have been unable to use their local supply wells since late July. The disruption follows a discharge of tailings from the Tranque 4 facility owned by Minera Las Cenizas during heavy rainfall.

Local residents and the Movimiento por el Agua y los Territorios (MAT) reported seeing a mixture of paste, turbid water, and sediment flowing through the Chinchorro ravine, eventually reaching the La Ligua River, which serves as a primary water source for the area. Company officials described the event as a “despiche”—a controlled discharge intended to reduce pressure on the facility and prevent structural damage to the walls—and stated the maneuver was coordinated with Sernageomin.

This incident follows a similar event in June 2024, which resulted in fines exceeding 51 million pesos from the Dirección General de Aguas. The Superintendencia del Medio Ambiente (SMA) has opened a new investigation into the matter, noting previous infractions regarding the insufficient dimensions and volume of the recovery water pools at the thickening plant.