A hanging wall movement detection apparatus includes a rigid elongate member which extends between a first end and a second end, an indicator module which produces a warning signal when actuated, axially movably engaged with the elongate member, a ground engaging support which rigidly supports the indicator module off the ground, an actuator engaged with the elongate member between the first end and the indicator module, a biasing separator between the actuator and the indicator module. The actuator is drawn towards the indicator module, compressing the biasing separator, when the elongate member experiences a pulling force at the second end in an axial direction away from the indicator module, and the actuator contacts the indicator module to actuate the module to produce a warning signal if the pulling force is of a sufficient magnitude to overcome the bias of the biasing separator.