A multi-criteria decision model for the assessment of sustainability and governance risks of tailings dams

The Brumadinho tailings dam collapse in 2019 killed hundreds and caused extensive damage to the surrounding area, including long-lasting environmental damage. Yet, this catastrophic event also triggered numerous proposals and activities to increase transparency related to environmental, social and governance (ESG) risks and sustainability in a broader context. Recently, several studies have proposed indicator-based approaches, but they generally lack a coherent aggregation and analysis of trade-offs and synergies between different sustainability criteria. Against this background, the current study seeks to create a global sustainability comparison of tailings dams at a country level, by combining harmonized data from multiple input sources through an iterative, multi-stage process. First, a comprehensive set of criteria and indicators is established that includes, among others, the impact on the environment, accident risks, and socio-political and governance aspects. Second, a dedicated Multi-Criteria Decision Analysis (MCDA) framework based on an outranking sorting approach (i.e., ELECTRE-TRI) is developed. Third, the evaluation system is applied to 43 countries that experienced at least one tailings dam failure since 1970, providing fact-based and transparent decision support to stakeholders and policy makers