Tailings storage is a critical aspect of any mining operation. The quality of design, construction and ongoing management of tailings storage facilities throughout their life cycle can define a mine’s legacy of environmental and social impacts. Unfortunately, the consequences of poor management can be disastrous, as seen in the recent collapse of a tailings dam in South Africa.
At the other end of the spectrum, recent innovations in tailings storage have seen mining waste used in beneficial ways. For instance, BHP is currently exploring methods of capturing and storing carbon from the atmosphere while stabilising waste compounds from its nickel mining operations.
There are valuable lessons to be gleaned from the failures as well as the success stories in the ever-evolving field of tailings management. Here are some notable recent examples of both.
Questions Raised by the Jagersfontein Tailings Dam Disaster
The Jagersfontein diamond mine in South Africa was the site of a recently publicised tailings dam disaster. A dam wall collapsed on the morning of 11 September, flooding nearby residential areas. Houses and cars were swept away, at least one person was killed, and 40 others were injured.
While full details regarding the cause of the collapse are unclear, the Jagersfontein disaster has raised pertinent questions about global standards. The Global Industry Standards on Tailings Management (GISTM) were established in 2020 as a benchmark for the safe management of tailings facilities. However, these standards have not yet been adopted by all mining companies or host countries.
There is also the question of clearly defined management roles and responsibilities, and the need to ensure tailings dam owners are well-versed in the risks, realistic whole-of-life costs and operational requirements of dam maintenance. Proactive regulatory oversight is critical to ensure companies comply with relevant legislation.
Brazil Dam Collapse Killed 270 and Devastated Local Communities
A Brazilian mining company was fined for failing to present reliable information pertaining to its Brumadinho tailings dam, which collapsed in January 2019. A torrent of toxic mud surged through the mine’s administrative area and nearby forests, rivers and communities, in what would later be described as ‘the worst human and environmental disaster in Brazil’.
Reports emerged afterwards that the mine owner had previously known about problems with sensors that were designed to monitor the dam’s structural integrity. Concerns around the tailings dams were apparently expressed by a company executive as early as 2009 – however, no action was taken in response. The International Journal of Applied Earth Observation and Geoinformation also published a paper revealing structural changes were evident at the dam up to 12 months prior to its failure.
Both the Jagersfontein and Brumadinho dam collapses serve to highlight the critical importance of adhering to industry-best practices in tailings management, and the weight of responsibility on mine managers to ensure these standards are consistently upheld.
What Causes Tailings Storage Facilities to Fail?
According to the International Commission on Large Dams (ICOLD), there are valuable lessons to be learned from international tailings storage facility failures.
Inadequate control of the water balance, poor construction control, lack of adherence to design principles and poor facility owner/operator understanding of operational safety requirements for tailings storage facilities have been identified as the key management problems that often precede failures.
Tailings incidents occur more frequently where upstream construction is employed, and in seismically active regions. Containment walls most commonly fail due to slope instability, earthquake loading, overtopping, inadequate foundations and seepage. However, risks can be substantially minimised through careful planning, design and management of tailings storage facilities.
The current focus on the closure of mine waste structures and associated tailings design requirements has sparked the development and implementation of new tailings management technologies that will also help to reduce environmental, social and governance (ESG) risks and assist in decreasing the gap between mining companies, stakeholders and their local communities’ expectations.
Carbon Capture Technologies: An Innovation in Tailings Management
Australian mining company BHP is pioneering a process of mineral carbonation, whereby mining waste is used to capture and store carbon from the atmosphere. This exciting new technology means that one dam now has the potential to store more carbon each year than the company emits from its iron ore and nickel mining operations.
The field trial, which began in 2021, is taking place at BHP’s Mt Keith tailings dam in Western Australia. A chemical reaction occurs when the magnesium-rich tailings interact with air, turning magnesium oxide into magnesium carbonate. The latter is a stable compound that can be safely stored in situ or used in building materials.
A scientific study, led by Sasha Wilson of the University of Alberta, has found that the Mount Keith dam could potentially store about four million tonnes of carbon each year, presenting an enormous opportunity for the mining industry.
Ensuring Success for Your Tailings Management Project
Hall Water & Tailings has a strong track record in delivering successful tailings management solutions to the mining and heavy industrial sectors. Our company’s commitment to quality ensures all our projects are delivered to the highest standards, maximising both business and environmental outcomes.
We work collaboratively with clients to identify the best solutions, and our services are always underpinned by comprehensive environmental, quality and safety frameworks. We support mining companies in adhering to industry-best practices, including supporting the Global Industry Standards on Tailings Management (GISTM), with the goal of decreasing risk and preventing tailings storage facility failures.
Whether you require operational maintenance, reprocessing or closure of facilities, Hall Water and Tailings can assist you with your tailings management requirements. Please contact us on +61 (7) 5445 5977 and our experienced team will be happy to assist you.