The Development And Testing Of A Geophysical Blast Movement Measurement Technique For Surface Mines

In order to minimize the ore dilution induced by blast movement in surface mines it is necessary to quantify<br>such movement. This will make it possible to more accurately locate the grade boundaries on the surface of a<br>blasted rockpile prior to excavation. This paper describes the development and testing of a method to accurately<br>measure the direction and magnitude of sub-surface blast movement. The technique involves the use of magnetic<br>gradiometry, using a cesium vapor gradiometer and real-time differentially corrected, GPS system, to locate the<br>post-blast position of magnetically enhanced target objects, whose pre-blast locations are known, without<br>disturbance of the blasted rock. The objective is to design an accurate and eflicient technique which can be<br>integrated into a mine’s production cycle.