During 2016, we made significant progress on our gradual closure works, with a total investment of US$ 22.53 million. This includes our subsidiaries Minera La Zanja S.R.L., Compañía Minera Coimolache S.A. and Sociedad Minera El Brocal S.A.C.
In accordance with our environmental policy and the laws in force, Buenaventura complies with the implementation of mine closure plans at all of its units.
Closure works are based on the physical, geochemical and hydrological stabilization of the terrain. To achieve this, we closely review the technical specifications set forth in the detailed engineering for the closure of tunnel entrances with effluents, shafts and barren material and tailings deposits, among other activities.
This is supplemented with new products that provide added value to the waterproofing of tunnel entrances, ensuring their long-term functionality. We also detail the closure costs of each component, guaranteeing economic planning and reducing costs, while always complying with the applicable laws.
Currently, our works for the closure of environmental liabilities are completely finished. The remediated areas (Lircay, Rifle, Ruminaqui, Ayacucho, Chaquelle and Huachocolpa) have been completely integrated into the natural landscape.
At the Esperanza, Angélica-Rublo Chico, Poracota, and Shila-Paula units, we successfully eliminated 100% of the effluents from the tunnel entrances, recovering the water tables and nearby water meadows and wetlands, as well as the communities’ grazing areas, controlling their physical, geochemical and hydrological stability by constructing watertight plugs at the tunnel entrances and applying water-expansive resins made from polyurethane and liquid cements. This methodology is also being applied at Recuperada, Julcani and Orcopampa with positive results.
We have also continued to conduct research with the goal of achieving technological improvements in the closure works at La Zanja and Tantahuatay where we have used tecnosoles (artificial soils) that will allow us to improve the physical and geochemical stability of the barren material deposits and pits. Additionally, we have continued to implement wetlands for the natural treatment of water in Orcopampa and Julcani.
Colquirrumi: A Milestone in Peruvian Environmental Legislation
In 1996, Compañía Minera Colquirrumi, a subsidiary of Buenaventura, voluntarily began works for the remediation of mining liabilities in Hualgayoc, Cajamarca, which had been caused by old mining companies between the 1920’s and 1940’s.
These works were carried out on 300,000 m2 of land located in El Sinchao and Hualgayoc, areas that have been completely recovered and are now suitable for agriculture and livestock activities. The total investment amounted to more than US$ 19 million.
The closure plan for Colquirrumi, submitted to the Ministry of Energy and Mines (MEM) in 2004, was the starting point for drafting the legislation that currently regulates the management of environmental liabilities in the Peruvian mining sector (Law 28271, whose Regulations were passed one year later via Executive Order 059-2005-EM).