Method for determining the movement of a blast movement monitor and associated rock as a result of blasting operations

A method for measuring the movement of boundaries between different portions of a heterogeneous rock body is disclosed. The method comprises placing a plurality of blast movement monitors in a rock body prior to blasting and noting the position of each blast movement monitor. The rock body is then blasted to break it up into a plurality of pieces. Thereafter the position of the blast movement monitors is located and based on this the boundaries of rock portions can be adjusted to account for the blast. This leads to a more accurate reporting of different ore bodies to the appropriate processor in a heterogeneous rock body. An apparatus for carrying out the method is also disclosed. The apparatus comprises broadly a said monitor and a receiver. The monitor comprises a transmitter received within a casing that in turn is received within a housing . Further the casing can move within the housing and self right so that it always transmits its signal in an upright direction.