A general requirement of mine site closure is that waste rock dumps, generated by the excavation of large quantities of overburden in open cut mines, should be rehabilitated to create stable, sustainable landforms. However, many factors affect the success or failure of attempts to stabilise and rehabilitate waste rock dumps. Dump “failure” (where major erosion has occurred at points on the landform) is often associated with the erosion of unstable and dispersive materials. The presence of these materials in waste rock dumps commonly results in the development of tunnel erosion, causing failure of berms at points where tunnels develop, creation of relatively unsafe landforms with widespread tunnels immediately below the soil surface, development of large gullies once tunnels collapse, and instability of rock drains overlying dispersive materials. This paper provides information on the factors leading to the initiation of tunnelling and the potential for both changes in spoil properties through time and waste dump design to influence tunnel erosion risk. Waste rock dump design and management practices are reviewed and recommendations are made on the usefulness of alternative prevention and control strategies for tunnel erosion of unstable and dispersive spoils.