The greatest danger of tailings ponds is dam failure , with the most publicized failure in the U.S. being the failure of a coal slurry dam in the West Virginia Buffalo Creek Flood of 1972 , which killed 125 people ; other collapses include the Ok Tedi environmental disaster in New Guinea , which destroyed the fishery of the Ok Tedi River . On average , worldwide , there is one big accident involving a tailings dam each year . Tailings ponds can also be a source of acid drainage , leading to the need for permanent monitoring and treatment of water passing through the tailings dam ; the cost of mine cleanup has typically been 10 times that of mining industry estimates when acid drainage was involved . Other disasters caused by tailings dam failures are , the 2000 Baia Mare cyanide spill and the Ajka alumina plant accident . ( See also List of tailings dam failures . ) Historically , tailings were disposed of in the most convenient manner , such as in downstream running water or down drains . Because of concerns about these sediments in the water and other issues , tailings ponds came into use . The sustainability challenge in the management of tailings and waste rock is to dispose of material , such that it is inert or , if not , stable and contained , to minimise water and energy inputs and the surface footprint of wastes and to move toward finding alternate uses
the Ajka alumina plant accident
Ajka alumina plant accident
Tailings