Dynamic Properties of Coal Waste Refuse in a Tailings Dam

Failure of tailings dams due to earthquakes occurred several times in the past, causing significant loss of properties and human lives as well as severe environmental problems. In the US, government regulatory agencies such as the Office of Surface Mining (OSM) and the Mine Safety and Health Administration (MSHA) require comprehensive seismic analyses in the design of tailings dams. This paper presents the results of an extensive laboratory testing program on coarse and fine coal waste refuses. Representative samples were taken from a tailings dam in the Appalachian coalfield. Shear modulus and damping ratio versus shear strain curves for the two types of refuse are established. In addition, the response of fine refuse to cyclic loading including the generation of excess pore pressure was investigated using cyclic triaxial tests. Implications for design are discussed.