In January 2019, a tailings storage facility in south-eastern Brazil collapsed causing the catastrophic loss of life of hundreds of people and criminal charges against employees of the mining company.
Since 2015 there have been more than 10 tailings/mine waste storage facility failures in countries such as China, Philippines, Israel, Mexico and Australia. Some failures have resulted in a loss of life or caused health, safety and environmental issues.
The global mining industry, through the International Council on Mining and Metals (ICMM), has responded strongly to these failures. Over recent years, mining companies have committed to improved governance of tailings storage facilities throughout each phase of the asset’s lifecycle.
In addition, there are changes foreshadowed to the two primary guidelines for tailings design and management from the Canadian Dam Association (CDA) and the Australian National Committee on Large Dams (ANCOLD).
While tailings dams can pose risks, they are also an essential part of many mining operations. The prevention of failures requires a combined effort from everyone in the industry, including mining companies, consultants, regulators and professional organisations.
Here are some key ideas for how companies can improve tailings management and governance to protect employees, communities and environment:
1. Maintain organisational stewardship
There needs to be organisational accountability and competency to achieve the key elements of the ICMM governance framework. This means having a clearly articulated strategy, with board approval, that sets the corporate governance program for the facility, with roles and responsibilities identified. This needs to be supported by training and competency building/ development programs for employees.
2. Defined documentation and processes
Clearly defined process for risk assessment, management of change and other tailings specific procedures are important. The documentation that sits behind these processes (e.g. Tailing Management Plan; Operation, Maintenance and Surveillance Manual, Emergency Response Plan) also need to be supported by ongoing reviews, modifications and training as required.
3. Apply ‘best available/applicable technology’ (BAT)
There are a number of technologies that can be used to ensure the physical stability of the tailings deposit. While previously many tailings facilities were wet, many operators are increasingly using alternative options such as dry-stacking, mud farming and thickening. Before considering which BAT methods to assess, there are some key principles to address which will provide a path to the technology. These principles include: eliminating surface water from an impoundment; promoting unsaturated conditions in the tailings with drainage amongst many others to achieve a fundamentally stable landform.
4. Define roles and responsibilities
Ensure there are clearly applied (Responsible, Accountable, Consulted, and Informed (RACI) principles for roles identified as associated with the tailings facility. These roles would typically include the owner’s team, engineer of record (or similar) and cover all phases of a facility’s lifecycle (from concept to closure).
5. Review and assurance
Independent reviews need to be conducted by suitably qualified and experienced tailings professionals. These reviews do not replace the need for internal technical reviews as well as the auditing of all processes and procedures associated with the facility.