Construction of €60 Million Mine Water Treatment Plant Approved in Aznalcóllar, Spain

en.Wedoany.com Reported - On October 19, the municipal government of Aznalcóllar in the Province of Seville, Andalusia, Spain, issued a construction permit to Minera Los Frailes for a mine water treatment plant. The facility represents an investment of approximately €60 million and is planned for construction over 18 months. It will employ a four-stage physicochemical treatment process to treat accumulated pit water at the Aznalcóllar mining site, supporting the restart of local zinc-copper mining operations.

The water treatment project first involves the Los Frailes open pit, which measures approximately 900 meters long, 650 meters wide, and about 160 meters deep at the pit mouth. The developer plans to drain the accumulated water from the pit to create conditions for subsequent underground tunnel construction from the pit bottom. Another old pit at Aznalcóllar, approximately 1,400 meters long and 700 meters wide, will also be incorporated into the mine water treatment arrangements.

The project plans to transport treated pit water through approximately 30 kilometers of pipeline to the Guadalquivir River. According to the developer's plan, cumulative discharge over 17 years will total approximately 85.52 million cubic meters, with an initial discharge flow rate of 450 liters per second for the first two years, subsequently adjusted to 90 liters per second. The treatment system employs a four-stage physicochemical process, and Minera Los Frailes has set a target cadmium concentration of 8.5 micrograms per liter in the treated water; the discharge arrangements have been questioned by environmental organizations and researchers.

The overall Aznalcóllar mining project represents an investment of approximately €460 million and is scheduled to resume zinc and copper ore mining in 2029. The Government of Andalusia approved the mining project and land rehabilitation plan on May 29, 2025, and the permit obtained in October 2026 pertains to the construction of the mine water treatment plant.