Tuesday 9th August 2022
8.00am - 3.15pm
Networking till 4.30pm
Great Eastern Hwy, Burswood
7.35am - 7.50am
Arrival and Registration
7.50am - 8.00am
Opening session, Welcome remarks
8.00am - 8.10am
Hon Bill Johnston
WA Minister for Mines and Petroleum, Energy, Corrective Services and Industrial Relations
Statement from Hon Bill Johnston
8.10am - 8.50am
Chief Operating Officer
International Council Of Minings and Metals
The Global Industry Standard on Tailings Management ; origins, content and ICCM response
The tragic loss of life and environmental damage following the catastrophic failure of the tailings storage facility at Brumadinho in Brazil in January 2019 led the ICMM, the Principles for Responsible Investment, and UNEP to convene the Global Tailings Review. That in turn led to the launch of the Global Industry Standard for Tailings management (‘the Standard’) in August 2020.
The Standard strengthens existing requirements for tailings management – and strives to achieve the ultimate goal of zero harm to people and planet – in a number of ways. Firstly, the Standard was derived through a co-convened multi-stakeholder process and is global in focus. Secondly, the Standard integrates social, environmental & technical aspects in a comprehensive manner, starting with the establishment of a comprehensive knowledge base.
Thirdly, it covers the tailings facility lifecycle – from site selection, design, construction, through management and monitoring, to closure and post-closure. Fourthly, it elevates accountability to the highest organisational levels and includes clear requirements for independent oversight. It also establishes clear expectations around transparency and disclosure.
At the point of launch, ICMM members committed to implement the Standard such that all facilities with ‘Extreme’ or ‘Very high’ potential consequences will be in conformance with the Standard within three years, and all other facilities within five years. This is an ambitious timeline. However, the Standard primarily focuses on ‘what’ companies should do to responsibly manage tailings facilities, rather than ‘how’ to do so. Consequently, ICMM has undertaken significant effort to develop additional resources on tailings management.
This presentation will provide an overview of the background to the Standard, its content and the work ICMM has subsequently undertaken to support implementation.
8.50am - 9.30am
University of Alberta
Design considerations for management AMD with dry stack filtered tailings
Design considerations for the management of acid mine drainage (AMD) with dry stack filtered tailings
The global mining industry has seen relatively slow but continuous development and application of dry stack filtered tailings over the last few decades. Interest in this technology has rapidly accelerated with the recent sequence of four serious tailings dam failures, beginning with Mount Polley in Canada (2014), followed by the failures at Samarco in Brazil (2015), Cadia Valley in Australia (2018) and Feijão in Brazil (2019). While all of these failures had a dramatic impact on the global mining community, the failure on August 4, 2014, at the Mount Polley tailings storage facility in British Columbia initiated the need for change in tailings management practices.
The Independent Expert Engineering Investigation and Review Panel (IEEIRP) tasked with investigating the breach of the tailings dam at Mount Polley provided major contributions for new guidelines.
The IEEIRP introduced comprehensive recommendations for best available tailings technologies (BAT) based on principles that included the elimination of surface water from impoundments and the promotion of unsaturated conditions in the tailings through drainage provisions. The application of these BAT principles for the surface storage of tailings leads to the use of filtered tailings technology. Filtered tailings technology or “dry stack tailings” can satisfy each of the BAT components when the impoundment is properly designed and constructed.
The implementation of the best available technologies for physical stability (BAT-PS) of tailings impoundments competes directly with the best available technologies for chemical stability (BAT-CS) of reactive tailings that produce acid and metalliferous drainage. New expertise in mine waste management will be required to achieve both BAT-PS and BAT-CS. This new expertise will include the application of unsaturated soil theory with special methods of analysis, laboratory testing and field instrumentation for designing new dry stack tailings systems.
Furthermore, the design of these new facilities may include commingling with waste rock to reduce acid mine drainage (AMD) in waste rock dumps as well as the de-sulphurization of tailings. These topics along with the management and closure these facilities will be discussed in the presentation.
Break 9.30am - 9.35am
9.40am - 10.20am
University of Queensland
Lessons from Tailings Dam Failures
Different regions worldwide have adopted various approaches to tailings management, as a result of the site settings and local practices as they have evolved. Tailings dam failures have continued to occur in both developing and developed countries, necessitating a range of tailings management approaches. These failures, while rare, continue to occur at a frequency that exceeds both industry and society expectations, and there is much to be learned from well-documented cases.
Tailings management continues to be overly reliant on a net present value approach using a high discount factor, rather than a whole-of-life approach that may result in safer and more stable tailings facilities and may also facilitate the eventual mine closure.
There is a need for the further development and implementation of new tailings management technologies and innovations, and for the application of whole-of-life costing of tailings facilities. Changes in tailings management will most readily be achieved at new mining projects, making change across the minerals industry a generational process.
10.20am - 11.00am
University of Queensland
The importance of site settings on tailings dam stability
The key site settings that must be taken into account in assessing tailings dam stability include the climate, the topography and the seismicity.
With respect to climate, what is most important is whether the climate is net evaporative or net infiltrative, which dictates whether or not upstream construction is possible.
Also important is the overall water balance and how rainfall is distributed throughout the year. A very high rainfall event can swamp a tailings facility. Topographic relief dictates the volume of “free storage” for tailings available in valleys, and the geometry of the tailings dam, particularly its height. In a dry climate, free storage in a valley can be devoted to storing tailings. In a wet climate the free storage must be shared by rainfall/precipitation and tailings. High seismicity will often govern tailings dam/storage design, and high seismicity will likely need to be considered post-closure (in perpetuity) everywhere.
Break 11.00am - 11.15am
11.20am - 12.10pm
Environ Pty Ltd
Management, Treatment and Disposal of Waste with PFAS at Mine Sites
Mine sites present various types of contaminated waste from tailing dams heavy metals to waste contaminated with PFAS. Firefighting foams are stored and used at mines site for operational firefighting and many of those foams have PFAS due to legacy use. As a result mine site waste and operational areas can and may be contaminated by PFAS due to PFAS foam use during training or operational firefighting and leakage and spillage of PFAS foam due to poor containment and storage. Hence waste with PFAS needs to be managed and treated accordingly to comply with Australian PFAS National Environment Management Plan and best environmental practice.
A number of management, treatment and disposal commercially viable option, approach and methodology are now available in Australia and overseas ranging from in situ temporary storage, soil and water PFAS treatment and incineration to disposal at landfills or licensed disposal facilities.
12.10pm - 12.40pm
University of Western Australia
Extracting Iron Ore from Mining Waste
Researchers at The University of Western Australia have developed a new chemical additive that increases iron ore yield while reducing costs and the environmental effect of mining waste.
Chemical engineer Professor Yee-Kwong Leong from UWA’s School of Engineering said the patented composite chemical additive would reduce the impact of tailings, which are unwanted mining by-products that go to waste during processing.
Professor Leong states that the UWA developed chemical additive could improve iron yield in wet processing situations by three to seven per cent which will enable the iron concentration of slurry to be increased to 58 per cent – the minimum required for sale. This presentation will discuss the process and how this chemical additive was developed in response to a growing problem of waste tailings being too fine and difficult to handle and too much water being used.
Lunch 12.40pm - 1.35pm
1.35pm - 2.10pm
University of Western Australia
Safe, Sustainable Management of Filtered Tailings
The key objective of this project is to facilitate the widespread adoption within the mining and processing industry of filtered and stacked tailings as a viable, safe and cost-effective management strategy.
Increasingly large volumes of the residue from processing of ore are being produced, as ore grades continue to decline. The resulting waste material must be securely stored as it constitutes a potential source of contamination. Failures of tailings storage facilities are unfortunately common, with more than five catastrophic failures in the past four years alone.
Filtering tailings to produce a partially saturated material has many potential benefits, including facilitating compaction of the tailings to produce a high density material.
However, managing filtered tailings is not without significant challenges, and considerations of geotechnical stability remain critically important. Filtered tailings are not a panacea for tailings managers. The talk will discuss the options for producing a filtered tailings product, methods for transporting the tailings and, crucially, deposition and placement options. Drawing on experience from projects around the world, some of the pitfalls of this technology will be discussed.
2.10pm - 3.00pm
University of Western Australia
Evaluation of Tailings Storage Facilities monitoring technologies
In the aftermath of recent devastating failures of tailings storage facilities and the ongoing occurrence (with a number of failures having occurred in 2022 already), a key focus for those responsible for managing these facilities is monitoring. Appropriate monitoring provides the opportunity to evaluate performance against predicted behaviour. Unfortunately there are currently a multitude of technologies being advocated for application to the monitoring of tailings facilities, with many of the vendors of these technologies making unsubstantiated claims about the relevance and value of their technologies. This talk focusses on achieving Meaningful Monitoring, i.e. monitoring that provides relevant data, something that is often surprisingly rare. Linking monitoring to credible failure modes is discussed, as well as instances where particular technologies are unsuitable.
3.00pm - 3.15pm
Q & A and Summaries
3.15pm - 4.30pm
After the event networking and close