DESTRUCTIVE MUDFLOWS AS A CONSEQUENCE OF TAILINGS DYKE FAILURES

Disastrous mudflows, involving the movement of large volumes of semi-l iquid tailings, have followed the failure of many tailings containment s, For instance, the mudflow that followed the failure of a tailings d am complex at Stava, Italy, killed nearly 300 people, However, in othe r cases tailings dams have failed with very little post-failure moveme nt or escape of tailings, This paper examines the behaviour and conseq uences of failures in five tailings ring-dykes in southern Africa and attempts to define the circumstances under which a mudflow will occur, It is shown that the occurrence of a mudflow is closely associated wi th the condition (dry or wet) of the ground surface on to which the es caping tailings move, If the ground surface is dry, it is likely that the tailings will not move far whereas if it is wet, a mudflow is much more likely to ensue.