Tailings storage facilities
The construction, operation and decommissioning of tailings storage facilities (including dams) involves managing multiple issues that have the potential to affect safe and sustainable mining operations and rehabilitation outcomes.
There are many publicised cases of tailings storage facility failures across the world. Safety consequences range from the displacement of downstream communities to significant injuries and the death of mine workers and members of the public.
Environmental impacts
Environmental impacts of failed tailings storage facilities have included:
- polluting downstream rivers and land
- groundwater contamination
- native wildlife poisoning through exposure to adverse tailings and dust generated from exposed tailings material.
Recent compliance activities have identified uncertainties and knowledge gaps in managing tailings storage facilities. The Resources Regulator’s goal is to ensure titleholders and mine operators in NSW are aware of their legislative obligations.
Promoting best practice in tailings storage management
Through ongoing engagement activities in the coal and metalliferous mining sectors, we want to clearly outline our expectations, continue to identify and address knowledge gaps, and share key lessons to promote leading practice in tailings storage facility management.
A key component of our compliance model is to educate and engage the regulated community. This includes facilitating information exchange on leading practice tailings management.
As part of the April 2019 tailings management workshop, we engaged Professor David Williams (University of Queensland) to present on leading practice tailings management as well as key life-cycle tailings management risks.
A key message provided by Professor Williams was that there is a move away from conventional slurry tailings to dewatered tailings technologies and other innovative tailings treatment methods which don’t necessarily rely upon the use of a tailings storage facility structure to contain the material.
Further research and innovation should focus on dewatered tailings that allow combining the material with other waste products such as waste rock to allow for integrated waste emplacement or co-disposal to enable a shift away from conventional slurry tailings storage facilities.
The information below provides a useful resource for mine operators on leading practice and consideration of key life cycle tailings management risks.
Guidance: Tailings leading practice - questions and answers by Professor WIlliams (PDF, 229.7 KB)
Consideration of risks
The mining industry must be aware that the risks to tailing storage facility management need to be considered throughout the life of a mining operation.
The Tailings Compliance Priority Project identified opportunities for improvement in how the mining industry assesses the risks associated with tailings storage facility management and adopts appropriate controls for hazards. In particular, the mining industry must be aware that the risks to tailings storage facility management need to be considered throughout the life of a mining operation (design, construction, operation and decommissioning) to enable effective implementation of controls that will ensure operations are conducted in a safe and sustainable manner.
Guidance on risk assessment
The Resources Regulator does not prescribe how mine operators should conduct risk assessments specific to tailings storage facility management. However, guidance is provided below for how mine operators should approach risk assessments for events that affect both workers safety (Work Health and Safety Act considerations) as well as environment, rehabilitation and mine closure matters (Mining Act considerations).
Work Health and Safety (Mining and Petroleum Sites) Act 2013 considerations
The Guide - Preparing a principal hazard management plan (PDF, 870.56 KB) provides information for how operators are required to consider risk to workers associated with tailings storage facility management. It is noted that tailings storage facility management is not listed as a ‘specified hazard’ in accordance with WHS (Mines and Petroleum Sites) regulation, however are considered as a component of the inundation and inrush hazards. Consideration of tailings storage facility management is required due to the reasonable potential to result in multiple deaths in a single incident or a series of recurring incidents.
The Guide - Notifying the Regulator of a high risk activity (PDF, 306.72 KB) provides notification requirements to the Regulator for operators undertaking listed high risk activities (HRA) in accordance with WHS (Mines and Petroleum Sites) Regulation. High risk activities are notified via the NSW Resources Portal.
Mining Act 1992 risk assessment considerations
Conditions of a mining lease granted under the Mining Act 1992 require the lease holder to conduct a rehabilitation risk assessment and implement measures to eliminate, minimise or mitigate the risks.
This assessment requires risk controls (or treatments) to be identified and justified, with risk treatment plans integrated into management plans and processes. As such, the implementation of risk controls for tailings storage facility management for closure is required to be clearly outlined in the rehabilitation management plan (RMP). The Regulator recommends that special consideration of tailings risk assessments and controls is undertaken in the RMP due to these mining domains having unique risks that may not apply to other areas of the mine.
A key consideration is that risks associated with tailings storage facility closures are required to be considered throughout the life of a mining operation (design, construction, operation and decommissioning) and not just be limited to the closure phase.
Guidance provided below may be useful for operators to consider the range of issues that the Regulator considers when determining the adequacy of controls implemented by mine operators to address risks associated with tailings storage facility closure.
Tailings storage facilities assessment programs
The Regulator has an ongoing planned assessment program for the principal hazard inundation or inrush that focuses on assessing a mine operator's management of the critical controls to prevent material unwanted event (MUE) for uncontrolled failure of containment of a tailings dam or water storage located on a mine site and evaluate the effectiveness of critical controls in the mine operator’s health and safety management system.
Further information on the planned assessment program can be found at the Resources Regulator assessment-programs. A fact sheet for inundation inrush tailings dams (PDF, 135.32 KB) provides further information on the assessment program.
Rehabilitation compliance
Further information on the Regulator's risk assessment processes can be found at Regulating risks to rehabilitation.
Other guidelines and Standards
Guidelines and Standards listed below are recognised by the NSW Resources Regulator as being relevant to tailings storage facility management and provide industry acceptable practice. There are legislative requirements for operators of tailings facilities to exercise due diligence by acquiring and keeping up-to-date knowledge of work health and safety matters. This includes knowledge of appropriate guidelines that apply to tailings storage facility management.
ANCOLD guidelines on tailings dams
The Australian National Committee on Large Dams (ANCOLD) is recognised as the primary industry advisory body for dams in Australia and provides a series of guidance on what is considered acceptable practice, including engineering performance criteria.
An addendum to these guidelines was released by ANCOLD in July 2019. The addendum provides important updates in response to recent tragic tailings storage facility failures. These updates reinforce the need for robust management practices as well as updates on earthquake considerations for static liquefaction.
Further information on these guidelines can be found at www.ancold.org.au.
Tailings management, leading practice, sustainable development program for the mining industry
These guides provide an overview of tailings management strategies and leading practice (including case studies). The guidelines facilitate general understanding of tailings management and are useful for consideration of alternate tailings management options and innovations.
See the Leading Practice Handbooks for sustainable mining guidelines.
Global Acid Rock Drainage Guidelines
The GARD guidelines addresses mine waste covers to manage Acid Metalliferous Drainage (AMD) issues. It is published by INAP (International Network for Acid Prevention) which is an industry-sponsored advisory body for issues relating to AMD.
ICMM/UNEP/PRI Global Tailings Review (August 2020)
The International Council on Mining and Metals (ICMM), the United Nations Environment Programme (UNEP) and the Principles for Responsible Investment (PRI) co-convened the Global Tailings Review to establish an international standard for the safer management of tailings storage facilities. This review has resulted in a Standard that provides 15 principles and associated requirements.