Mining has evolved in the 21st century into an indispensable industry that provides a variety of mineral products needed to sustain a modern society. To achieve efficiency, it has also grown into an integrated enterprise of enormous size, wielding substantial economic power. Tailings is essentially a fine-particle mine-waste byproduct. Its management has gone through major transformations in the last century. In early years tailings was disposed of out of sight and literally out of mind. However, due to the physical and chemical characteristics of tailings, this laissez-faire approach in dealing with its disposal led to significant environmental degradation such as pollution and blockage of watercourses, etc. With the rising environmental protection movement, the mining operation is under increasing regulatory constraints and governmental monitoring. Modern tailings dams have become major hydraulic structures designed, constructed, monitored until they are properly closed andreclaimed after the completion of mining tenure. These dams are often higher than 100 m, with a storage capacity of over hundreds of million cubic metres, serving a vital industrial function for the public. Unfortunately, when such a dam fails, it unleashes enormous destructive power causing inundation of water and tailings mud over the downstream area resulting in fatalities and lasting environmental degradation. This book presents a condensed monograph on forensic investigations of select case histories of failed tailings dams. The selection tends to emphasize recent cases that have representative characteristics including those affecting the evolution of the current practice of tailings dam engineering. Efforts are made to facilitate readers’ understanding of important factors involved by using plain language. Technical terms are clearly explained before their usage. The objective of the monograph is to provide a neutral reference on tailings dam failures for all stakeholders.The author hopes ongoing dialogues by all stakeholders on the important topics of dam safety will raise the safety standard of tailings dams to a new level compatible with public expectations of the sustainable mining industry.