Responsible mining: tailings facilities

Tailings facilities are essential for responsible mining. They help manage waste and minimize our impact on the environment. Their design, operation and monitoring are important to ensure they function as intended.

Tailings facilities consist of ground rock, unrecoverable metals, chemicals and organic matter from the extraction process. Once a mine is decommissioned tailings facilities undergo long-term stabilization and monitoring to ensure structural integrity and environmental safety. Where feasible, these areas may eventually be rehabilitated for alternative uses such as wildlife habitats, parks or recreational areas.

We design tailings facilities that are appropriate for local conditions. At First Quantum we use three common types of progressively raised tailings dams, called upstream, downstream and centreline. The dam type is based on the characterization of the site, the seismic risk, the availability of materials and the geotechnical characteristics of the actual tailings.

Each of our tailings facilities are subject to annual inspections at a minimum, risk review and reporting by external specialist and have the following controls in place to ensure they are properly and efficiently run:

• TSF management review and risk oversight by the Environment, Health and Safety Committee of the First Quantum Board
• Appointment of competent persons at the mine to manage the facility with all reporting directed to the Site General Manager
• Use of approved Operations Maintenance and Surveillance Manuals prepared for each TSF
• Regular inspection by the day-to-day operators with overview from senior management
• Close monitoring of the volume of water held in the TSF with particular attention to embankment freeboard, drainage and beach length
• Use of drones for aerial surveillance of the TSF and tailings deposition
• The installation of industry leading instrumentation including piezometers (to measure the presence and level of the phreatic surface), inclinometers and settlement gauges to provide detailed feedback on the developing embankment
• Groundwater quality monitored via peripheral water monitoring bores
• Emergency Response Plans in place for all of our facilities. These include regular drills to test evacuation procedures as well as engagement with relevant third parties such as emergency services and local authorities