Tailings Storage Facility

What are Tailings and TSFs?

Tailings are the left-over materials from the processing of mined ore. They consist of ground rock, unrecoverable and uneconomic metals, chemicals, organic matter and effluent from the process used to extract the desired products from the ore.

Tailings generally leave the mine processing plant in a slurry form (diluted with water) and are often but not always stored on the surface in storage facilities called tailings dams, or tailings storage facilities (TSFs). 

How tailings dams differ from conventional water dams

The principal difference between tailings dams and conventional water dams is that tailings dams are dynamic structures that grow over the life of the mine to accommodate increased tailings. Tailings dams, and particularly ‘upstream’ dams (see types of dams below), often rely on the strength of hydraulically placed tailings that are variable in strength due to mine processing changes, operational practices on deposition and climate variations. 

Tailings dams are usually constructed from earth and rock waste materials from the mine with variable design life (continuously constructed) whereas water dams  can be constructed from earth, rock, concrete and other materials and are typically erected in a single phase of works. 

Tailings dams

  • Life cycle of tailings dams

    Tailings dams evolve over their life cycle, from planning, design, construction, operation, closure and post closure. There may also be periods of care and maintenance between operational phases.

     

    Life cycle 

     

    The duration of the closure phase in a tailings dam’s life cycle can often exceed the duration of the operational phase. It may include transition from operations to active care such as ongoing water, geochemical and physical management to maintain integrity. 

     

    Over time, inactive TSFs may transition to passive care when the ongoing water, geochemical, and physical management requirements are reduced or eliminated.

  • Types of tailings storage facilities construction

    There are three broad types of dam construction which are depicted below. The choice of design is based on factors such as dam location, geology, seismicity, climatic conditions, construction materials and the nature of the tailings.

     

  • Key factors that may influence tailings dam integrity

    Maintaining dam integrity requires ongoing focus on appropriate engineering design, quality construction, operating discipline and effective governance with independent reviews. Key internal and external factors that influence dam integrity include: assessment of site conditions (such as seismicity, climate, geology, hydrology, tailings characteristics); the quality of assurance and quality control of dam construction; and ongoing dam operating discipline management including tailings characteristics, water management, monitoring and consideration of changes to any of these factors.

     

    For more information on how BHP approaches management and governance of our TSFs, please see Tailings storage facilities management: Governance, our approach, risk management and key targets.

Sustainability case studies, organisational boundary & disclaimers, and downloads

BHP Annual Report 2022 pdf 9241549 download-img Sustainability reporting organisational boundary and disclaimers pdf 97477 download-img Límite organizativo de los informes de sostenibilidad y descargos de responsabilidad pdf 27433 download-img BHP ESG Standards and Databook 2022 xlsx 10641635 download-img BHP Modern Slavery Statement 2022 pdf 6760135 download-img BHP’s Climate Targets and Goals pdf 137671 download-img BHP Climate Transition Action Plan 2021 pdf 2677572 download-img BHP Climate Change Report 2020 pdf 3112031 download-img BHP Scope 1, 2 and 3 GHG Emissions Calculation Methodology 2022 pdf 385823 download-img BHP Scope 1, 2 and 3 GHG Emissions Calculation Methodology 2021 pdf 210140 download-img BHP Scope 1, 2 & 3 Emissions Calculation Methodology 2020 pdf 609426 download-img CDP 2022 Submission Not Graded pdf 903906 download-img BHP Tailings Storage Facility Policy Statement pdf 216318 download-img 2021 BHP Tailings Storage Facility Management Update link-icon FY2019 Church of England Disclosure pdf 902015 download-img Information for social investment partners pdf 278686 download-img Case studies link-icon