Mine Tailings Storage: Safety Is No Accident

Introduction Industrial scale mining generates huge volumes of waste tailings. The way mining companies deal with these tailings can have major long-term implications for local communities and the environment. The largest tailings storage facilities are among the biggest man-made structures on Earth. The are expected to provide “secure” storage of tailings in perpetuity. But is this a realistic expectation? Recent tailings dam failures have provided evidence that tailings storage facilities are not always safe. For example, the 2015 Samarco mine tragedy in Brazil resulted in 19 deaths and polluted hundreds of kilometres of river (see case study, pg 17). Even when fatalities do not occur, the failure of tailings storage facilities can have lasting social, environmental and economic consequences and often prove extremely difficult and costly to remediate.

We understand that the failure to implement adequate tailings dam standards, guidelines and risk controls can result in catastrophic events. So, is there a way to reduce the risk of dam failure? Are there some practices that are inherently riskier than others that should be reconsidered? And are there alternatives to the commonly accepted tailings storage and disposal methods? Tailings storage facilities are built by industry and should be regulated by governments, however, all stakeholders, particularly local communities, bear the impact of failure. The recently commissioned International Council on Mining and Metals (ICMM) report (Golder and Associates 2016) concludes that we have the means to ensure the safe management of mine tailings, we just need to make sure this occurs. Numerous well-conceived initiatives have, over the past decades, made recommendations to improve mine waste management (Figure 3). Examples include the Mining, Minerals and Sustainable Development Project (MMSD 2002 and Buxton 2012), the World Bank Extractive Industries Review (Salim 2003) and the 2001 ICOLD report. Franks et al. (2011) developed a set of sustainable development principles for the disposal of mining and mineral processing waste. Most recently, the ICMM produced a specific tailings-focused report (Golder and Associates 2016) and a position statement on preventing the catastrophic failure of tailings storage facilities (ICMM 2016). National industry bodies, such as the Mining Association of Canada, also produce guidance on tailings management, which their members are required to follow (MAC 2011). However, despite all these guiding

principles and recommendations, major failures are still occurring (Figure 3) and are predicted to continue (Bowker and Chambers 2015).

The United Nations Sustainable Development Goals should support and underpin the mining industry’s contribution to development objectives and their social licence to operate. The licence should acknowledge that the failure or poor performance of a tailings storage facility can be fatal for communities and can cause widespread damage to the environment on which they depend. A commitment to sustainable development requires early and ongoing consultations, where information sharing and dialogue with stakeholders are required during the design, operation and closure phases of every mine. This needs to be supported by transparent compliance with industry-specific guidelines and by applicable government regulations, to establish a practical and ethical basis for mining to contribute to sustainable development and safely store tailings. From the earliest planning stages, sustainable closure of tailings storage facilities requires the incorporation of closure landform design that will ensure sustainable post-mining land use and ecological function. Sustainable development and mine tailings (adapted from LPSDP 2016)

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