Application of inspection and monitoring in the reduction of risk for mine tailings dams

Abstract

Recent high-profile failures of mine tailings dams across the globe have once again raised geotechnical interest in these structures. Much of the recent discussion in the technical literature has focused on the prediction of the ultimate stress state and thus of the failure potential of tailings materials. Concentration solely on geomechanical properties is important in the understanding of the fundamental characteristics of extractive waste but limits the appraisal of risk potential in these complex and multi-faceted structures. It is evident from the author's study of failures of extractive waste facilities over a period of some 50 years that knowledge of geomechanical properties alone would not have prevented disasters in many instances. The fundamental risks posed by these structures are reviewed in this paper with respect not only to their design but also to their construction, operation and eventual closure. The analysis confirms that other crucial elements of design and construction, if neglected, potentially pose higher risks than a lack of knowledge of geomechanics alone. A broad list of risk reduction criteria that should be applied to mine tailings dams is presented and examples of where and how such neglect has resulted in recent high-profile failures are cited. A review of general risk reduction criteria is presented and compared with existing standards and guidelines.