Remediation of the Excélsior Scrap Yard in Cerro de Pasco

CPS Peru, as part of a consortium, carried out supervision work for the remediation of the Excélsior tailings pond in the Cerro de Pasco region of Peru. The closure of the Excélsior tailings pond is the largest environmental remediation project in Peru and one of the most significant in Latin America.

The Excélsior Landfill received mining waste from the Raúl Rojas open-pit mine in Cerro de Pasco from 1956 through 2000, accumulating approximately 50 million metric tons , the leachate from which contaminated the soil and air over an area of approximately 69 to 79 hectares.

Most of the work still to be done relates to the irrigation system, including distribution lines and irrigation equipment. This major project benefits more than 10,000 residents of the communities of Champamarca and Quiulacocha in Cerro de Pasco.

The remediation work and follow-up monitoring were organized into three main components:

Physical Stability:
- Reshaping and grading of massive slopes at an elevation of more than 4,300 meters above sea level.
- Construction of retaining structures and reinforced concrete walls to mitigate the risk of landslides and geotechnical instability.
Chemical Stability:
- Containment and sealing of pyrite-bearing material that has the potential to generate acid mine drainage (AMD).
- Installation of a multi-layer roofing system (waterproofing and insulation) to prevent water infiltration and contact with oxygen.
Hydrological Stability and Revegetation:
- Construction of spillway channels and stormwater management to divert clean runoff away from the reservoir.
- Water insulation and surface revegetation for the gradual restoration of the high-Andean landscape.