The issue of Mine Tailings Management is once again attracting media and shareholder attention globally. We are at a crossroads for an industry balancing growing demand for minerals with slimmer operating margins and greater calls for risk management and sustainability.
With depleting ore reserves the quantity of tailings generated is increasing. In 2010 alone the industry generated around 14 billion tonnes of mine tailings and it is estimated that there are around 3,500 Tailings Storage Facilities (TSFs) around the world. Wet tailings can have a major impact on the community living in the vicinity of mining activity and carry significant environmental risk. Calls for greater transparency are mounting from all stakeholders including the mining industry, investors and governments in mining countries around the world.
Recent examples include:
- The public disclose of TSF audits by major mining companies, as stand-alone reports or listed under sustainability targets in their annual financial reports.
- The launch of a Global Tailings Review by the International Council on Mining and Metals (ICMM) together with the Principles for Responsible Investment (PRI) and the United Nations Environment Programme (UNEP) in June.
- Independent non-profit organizations such as the Responsible Mining Foundation (RMF) encouraging responsible mining by transparently assessing the policies and practices of large mining companies on a range of economic, environmental, social and governance (EESG) issues.
- We are also seeing legislation by some local governments forcing mining companies to treat the tailings they generate and to stop the usage of tailings dams.
The framework for tailings management considers key development pillars: technological, economic, environmental, policy and social aspects. It incorporates tools for determining trade-offs inherent in different tailings management methods during operation and throughout the life of mine which include Life Cycle Assessment (LCA), Net Present Value (NPV), Decision Analysis, and others.
The design and management of a TSF requires a multi-disciplinary approach as it involves civil and environmental engineering, geology, hydrology, geochemistry, mechanical engineering, process engineering and mine planning.
This puts a lot of pressure on mining companies to divest resources away from mining and mineral development activities, with an increasing dependency on external specialists for design and operation of the TSF. Large mining corporations do have their own tailings specialists but still have to rely upon external specialists for quality assurance and monitoring of the TSF. They are following an increasing number of global and national guidelines and best practices including (but not limited to) the IFC, Mine Waste Directive, the EC Seveso II directive, the Equator Principles directive, guidelines developed by the International Commission on Large Dams (ICOLD), the Canadian Dam Association and others.
A safer and more sustainable alternative to wet tailings
The mining industry is showing greater willingness than ever before to make investments in safe and sustainable solutions for managing tailings as compared to the earlier days. We have started seeing actions within the financial and regulatory context but more needs to be done to ensure safe and sustainable mining operations and to improve the industry’s reputation as well as profitability.
In particular, we need to find cost-effective ways to dewater mine tailings as the presence of large quantities of stored water in the tailings can lead to tailings dam failures. Such disasters can be averted by dewatering the tailings using mechanical separation to enable dry stacking or paste backfill thereby reducing the risk of storing ponded water. After all, no free water means no risk of dam failures! Dry centrifuged tailings also offer significant operational cost savings and recovery of process water.
Amol Chinchankar will deliver a presentation on 'Safe and Sustainable Tailings Management using Solid Bowl Centrifuge', at the upcoming IMARC event, taking place in Melbourne 29-31 October 2019.