TSF life cycle

Tailings storage facilities (TSFs) must be operated, closed, and rehabilitated to ensure minimal risks to operator and public health and safety, as well as acceptable low impacts on the community and the environment.

Leading principles in the management of tailings emphasize a risk-based approach throughout the planning, design, construction, operation, closure, and rehabilitation of TSFs. In this approach, tailored plans are essential to effectively manage TSFs throughout their entire life cycle while addressing potential risks within acceptable limits. TSFs classified as high consequence category demand greater rigor during design, stringent quality control during construction, and heightened focus on risk management, emergency planning, and documentation during the operational and closure phases.

The life cycle of a TSF comprises the following phases:

Project Conception and Planning: This phase begins during the initial planning of a proposed TSF and is integrated with site-wide planning, including mining and ore processing. It involves rigorous decision-making tools to support site selection, the outcome of the multi-criteria analysis, and the choice of technology for tailings management.

Design: Design work begins when a mature knowledge base is available, and the TSF location aligns with long-term mine planning. Comprehensive engineering designs are developed for all TSF aspects and associated infrastructure.

Initial Construction: This phase includes constructing necessary features, structures, and infrastructure before tailings deposition starts. Activities may involve site clearance, construction of starter embankments, drainage systems, tailings delivery pipelines, access roads, and water management infrastructure.

Operations and Ongoing Construction: This phase entails the transport and deposition of tailings into the TSF. Embankment raising occurs in stages or lifts, using downstream, centerline, or upstream methods, each involving the crest advancing downstream, vertically upwards, or upstream, respectively, with progressively less containment wall earthworks.

Standby Care and Maintenance: This phase occurs when commercial mining operations have ceased, and tailings placement has stopped. Surveillance and monitoring continue because the owner anticipates a future resumption of commercial operations. The facility and its infrastructure remain intact, and the closure plan remains on hold.

Closure: Closure begins when tailings deposition into the TSF permanently stops. The facility and its infrastructure are decommissioned, and the closure plan is implemented. This includes:

• Transitioning from operations to permanent closure;
• Removing infrastructure like pipelines;
• Implementing changes to water management or treatment; and
• Recontouring or revegetating tailings and any containment structures or other elements.

Post-closure: This phase begins after decommissioning work is complete, the closure plan has been executed, and the TSF has transitioned to long-term maintenance and surveillance. During this phase, responsibility for the TSF may transfer from the owner to jurisdictional control.