Surface tailings impoundments can represent one of the more significant environmental risks for the mining industry. Lundin Mining takes considerable care to ensure our tailings facilities are well-designed, built in accordance with leading industry practices and standards, well-maintained, inspected, independently reviewed, and carefully monitored.
Policies and Standards
Lundin Mining’s Responsible Mining Policy includes a specific Tailings Management Technical Standard. All Lundin Mining’s operations manage their tailings in accordance with this technical standard, developed in 2015, and currently under update. This technical standard requires that all tailings facilities, including major water retention dams, are planned, designed, constructed, operated, and, in the case of inactive or closed facilities, decommissioned and closed in such a manner that:
All structures are stable; and
All aspects comply with regulatory requirements, accepted international practice and any commitments to local stakeholders.
Monitoring and Surveillance
A requirement of the Tailings Management Technical Standard is for all sites to conduct regular geotechnical, hydrogeological and environmental monitoring to meet regulatory requirements and prevent the uncontrolled release of tailings and/or water to the environment.
All sites employ monitoring and surveillance systems which may include surface prisms, piezometers, inclinometers, remote sensing and other technologies to monitor tailings dams and water levels. Trigger action response plans (TARPs) provide clear guidance on how to respond to pre-determined trigger levels for surveillance activities.
All active tailings facilities have a closure plan which includes long-term monitoring requirements. The monitoring plan for the closed Ojos del Salado tailings facilities is under development and will be evaluated further in 2021.
Sites are required to identify a Responsible Person (RP) to ensure ownership and proper management of the tailings facility. The RP guarantees procedures for each facility, including an Operating, Maintenance, and Surveillance (OMS) Manual and Emergency Preparedness and Response Plan, are regularly documented and made available to site personnel.
The RP is an appropriately qualified, experienced and site-dedicated individual employed directly by the site. This person typically has an environmental or engineering background.
Tailings dams are regularly inspected by trained operators and technical staff, sometimes as frequently as several times daily, with formal documented staff inspections at least quarterly.
Engineer of Record
Each active and inactive tailings facility has an appropriately qualified, licensed and experienced third-party geotechnical engineer to act as an external Engineer of Record or Design Engineer in the relative jurisdiction.
Dam Safety Inspections
Formal dam safety inspections are conducted at least annually by the external Engineer of Record, and reports are issued to the Responsible Person for action on recommendations.
Tailings and water dam safety focused risk assessments are reviewed and updated at least annually and include input from site and corporate staff, the Engineer of Record and independent reviewers.
A component of the Tailings Management Technical Standard is the requirement for regular independent third-party tailings reviews, which are recognized as a leading practice for effective tailings and water dam stewardship. The reviews are focused on impoundment stability and integrity.
Annual site visits this year for the independent reviewers are all scheduled in the fourth quarter 2021. In addition, online progress meetings with the independent reviewers and Engineer of Record (EOR) are scheduled throughout the year to closely track progress made on outstanding recommendations.
Results from the independent reviews are carefully tracked, and progress updates are sent to the Board-appointed HSEC Committee each quarter.