Blast induced Rock Movement Measurement for grade control at the Phoenix mine

Controlling ore loss and dilution is critical for most mining operations. Typical grade control procedures rely on blast hole samples to determine the ore grade and establish the digging polygon boundaries. If the boundaries are wrong, this can cause a considerable revenue loss each year due to dilution and reduced mineral recovery. Movement of the initial polygon boundaries due to blasting, unless corrected for, has the potential to severely diminish the accuracy of even the most precise ore production estimates. This paper discusses a practical method, using 3-D data, to measure the rock movement due to blasting called "Blast Movement Measurement (BMM)". This method has been developed to measure the movement of the rock due to the blast, and to modify the pre-blast location of the digging polygons based on the results, in order to improve grade control. BMM uses a series of transmitters (BMM balls), a detector to locate the BMMs after the blast, and the BMM software that gives the movement vectors. The transmitters (BMMs) are activated, programmed and installed in the drill holes prior to the blast, and the detector locates the transmitters after the blast. The software then calculates and summarizes the movement of each BMM. This information helps in redefining the ore boundaries and enabling improved ore and waste selection, resulting in a genuine step change in grade control, which leads to better blast design. The thesis will include results from a measurement program at Newmont's Phoenix mine in Nevada.