Tailings storage facilities

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Our ambition

At BHP, our purpose is to bring people and resources together to build a better world. One way we do this is by focusing on the safety and integrity of all TSFs across our operated and closed assets to protect people, the environment and communities where we operate.

Our approach and position

Following the tragic TSF failures at Fundão dam at Samarco in 2015 (a non-operated joint venture (NOJV) owned 50 per cent by BHP Brasil) and Brumadinho dam at Vale’s iron ore operation in Brazil in 2019, we continue to evolve our approach to TSF management.

Our approach to tailings storage facility (TSF) risk management at our operated assets is aligned with our standard approach to risk management, assurance and continuous improvement. It is multi-dimensional, encompassing management of controls and governance, with particular focus on four key areas:

TSF selection (location and type), design and construction
operation, monitoring and maintenance
dam safety reviews
emergency preparedness and response

For more information see sections below on Governance and oversight, and Risk management.

Our tailings storage facility management evolution

Our short-term strategy focuses on improvement of key risk indicator performance at our operated assets, including studies to reduce and mitigate potential downstream impacts, particularly to those who could be at risk in the event of a TSF failure. Our medium- and long-term strategies focus on complex risk reduction projects and the identification and use of improved tailings management and storage solutions. Where there is a requirement to increase the current tailings storage capacity or construct a new TSF, we investigate cost-effective tailings management solutions, including non-conventional tailings solutions, as part of our efforts to reduce potential risks (aligned to our risk appetite) and increase social value.

For more information see sections below on Governance and oversight, Risk management, and Performance and disclosures.

What are tailings and tailings storage facilities?

Tailings are the leftover 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 are stored in tailings storage facilities (TSFs). TSFs are dynamic structures that accommodate the leftover materials from the processing of mined ore.

There are different types of TSFs:

surface facilities, including paddock style or valley fills, which can comprise multiple dams (or cells) that have continuous, structurally similar interconnected walls
in-pit facilities
dry stack facilities

How do TSFs differ from conventional water dams?

TSFs are dynamic structures that often grow over the life of the mine to accommodate increasing tailings volume whereas water dams are typically erected in a single phase of work. The construction materials can also differ. TSFs are usually constructed from earth and rock waste materials from the mine, whereas water dams can be constructed from earth, rock, concrete and other materials.

Tailing storage facilities

There are three broad types of TSF construction, which are depicted below. The design choice is based on factors, including:

TSF location
site conditions (geology, seismicity, climatic conditions)
construction materials
tailings characteristics

Types of tailings storage facilities

For more information on TSF integrity see section below on Risk management – TSF operation, monitoring and maintenance.

Lifecycle of tailings storage facilities

TSFs evolve over their lifecycle, from planning, design, construction, operations, closure and ultimately to post-closure. There may also be periods of care and maintenance between operational phases.

Lifecycle of tailings storage facilities

The duration of the closure phase in a TSF’s lifecycle can exceed the duration of the operational phase. The closure phase may include transition from operations to active care when tailings deposition ceases. Active care typically includes a continuation of water, geochemical and physical management processes that are designed to maintain TSF integrity. Over time, inactive TSFs may transition to passive care or safe interim closure, when the ongoing water, geochemical and physical management requirements are reduced or eliminated. Once a TSF has transitioned to passive care, additional works may be carried out to rehabilitate the site, such as earthworks and re-vegetation.

Governance and oversight, engagement and partnerships

Governance and oversight

Our approach to TSF management focuses on strong governance and effective risk management. Our BHP Tailings Storage Facility Policy Statement outlines our commitment to the safe management of TSFs and our approach to governance and risk management, transparency, emergency preparedness, response and recovery in the event of a failure.

Our tailings and water storage facilities global standard governs how we manage TSFs across our assets. The standard requires us to implement a management system that meets all the requirements of the six Global Industry Standard on Tailings Management (GISTM) topic areas and additional BHP-specific requirements, including independent assurance across the entirety of the mine lifecycle.

The standard also describes specific governance roles associated with the safe management of TSFs, including Accountable Executives who are direct reports of the CEO and communicate with the Sustainability Committee on matters related to TSFs.

For information on the role of the BHP Board in overseeing our approach to and delivery on sustainability refer to the Sustainability approach webpage. For more information on tailings governance see our GISTM Public Disclosure.

Engagement and partnerships

Actively engaging with our stakeholders regarding our TSFs is a priority. This includes other industry participants that we are working with in our ongoing effort to realise positive outcomes at BHP and across the industry.

Industry participation

We have contributed to improvements in tailings storage management across the mining industry, including through the ICMM Tailings Working Group. We are participants in other tailings working groups globally, including those associated with the Canadian Dam Association, Australian National Committee on Large Dams, Australasian Institute of Mining and Metallurgy, Minerals Council of Australia, Mining Association of Canada, Society for Mining, and Metallurgy and Exploration.

We have formed a collaboration agreement with Rio Tinto to accelerate the development of technology that could significantly increase water recovery from mine tailings, and in turn, reduce potential safety risks and environmental footprints associated with TSFs. For more information refer to this news article.

In conjunction with Rio Tinto and the University of Western Australia, we have developed Future Tails, an initiative focused on training, education, research and best practice guides in the tailings management space. For more information refer to the Future Tails case study.

Risk management

We operate to a single Risk Framework for all risks, including TSF failure risks at our assets. We use key risk indicators, set by senior management, to help monitor performance against BHP’s risk appetite. Our Risk Framework requires the pursuit of risk reduction actions to eliminate or reduce exposure to TSF failure risks until they are within BHP’s risk appetite.

For more information on our Risk Framework, which we operate to for all risks (including TSF risk), refer to our BHP Annual Report and GISTM Public Disclosure.

Performance and disclosures

We continue to work with industry to support the development of disclosure standards and improvements for tailings storage management across the mining industry, including through the ICMM Tailings Working Group and our support of the Investor Mining and Tailings Safety Initiative. We publish and regularly update our information and commitment to safe TSF management on our website, and disclosure information about our tailings portfolio annually in our GISTM Public Disclosure.

Global Industry Standard on Tailings Management

We are committed to achieving alignment with the global benchmark for social, environmental and technical outcomes described within the GISTM for all operated TSFs. We support detailed, transparent and integrated disclosure regarding TSF management, publishing a GISTM Public Disclosure document on our website for all TSFs in alignment with the GISTM. We have engaged a third-party contractor to progressively validate GISTM conformance aligned to the ICMM recommended timeframes.

For more information refer to our most recent GISTM Public Disclosure.

Case studies