Antamina Tailings Dam, Tailings dam in Huincush Ravine, Ancash Region, Peru

The Antamina Tailings Dam is an embankment structure in Huincush Ravine, Ancash Region, designed to store processed materials from mining operations. The dam spans 1,300 meters (4,265 feet) in length and rises 215 meters (705 feet) high, with a geomembrane lining and water diversion channels from the Ayash River maintaining its structural stability.

Construction of the facility began in 2000 as a concrete-face rockfill structure and reached completion in April 2001 at an elevation of 4,010 meters (13,156 feet). The initial structure rose 130 meters (426 feet) high and has been expanded since to meet growing demands from mining operations.

The dam takes its name from the Antamina mine, whose Yanacancha concentrator sends its tailings here; Antamina ranks among Peru's largest producers of copper and zinc concentrates and among the ten largest mines in the world by output volume. The reservoir is lined with a geomembrane, and water released to the environment is purified to meet standards, with discharges kept at no less than 150 litres per second.

The dam is an active industrial facility at about 4,045 m above sea level in Huincush Ravine, 55 km east of Huaraz; access requires prior authorization and is not open to tourists. The structure is being raised in stages, so the crest and surrounding works change over time. Water released downstream is treated and discharged at no less than 150 liters per second.

The water management system operates at a discharge rate of 150 liters per second diverted from the Ayash River. Treatment systems continuously monitor water quality to maintain environmental standards in a remote mountain location.