For coal mines the term bump should refer to a seismic event that is generated at some distance from the excavation and a burst should refer to a sudden uncontrolled fall of ground. There may be additional seismic noise generated at the excavation boundary directly associated with the fall of ground. The seismic sources for bumps are most likely to be the immediate or delayed failure of thick rock units in the overburden. For Australian coal mines, the sudden collapse of ribs should be considered to be either a strain burst in the context of the hard rock mining knowledge base or a gravity–driven kinematic failure (slump). As the depth of cover increases there is a greater thickness of failed coal at the excavation boundary and hence more material is available to be dislodged as a strain burst if the installed ground support is inadequate. Depending on the orientation of the roadway with respect to small-scale faults it is possible for wedges of coal to be defined, and these may be dislodged by a seismic bump. The dimensions of such wedges may be in excess of the maximum practical tendon length.