Interpretation of mill vibration signal via wireless sensing

Abstract

Tumbling mills emit vibration that can be captured to assess its performance. We interpret the vibration signature of a one meter diameter mill in response to changes in mill speed, rock/particle size, quantity of balls, and slurry viscosity. A ±500 g tri-axial accelerometer with a wireless transmitter located on the surface of the mill shell transmits vibration signal to a receiver connected to a PC. The quality of the vibration signal is preserved due to the use of wireless transfer of data. The filtered vibration signal in the frequency domain is averaged which is then used as a parameter for comparison purpose. This approach to signal analysis is most suitable to compare vibration response of a mill to changes in operating parameters. The mill shell vibration signature turned out to be an excellent indicator to establish the differences in mill performance under wet versus dry grinding conditions, coarse versus fine grinding, changes in mill speed, ball load, etc. The broader implication of the main observations in the context of development of a diagnostic tool to assess the mill performance is highlighted.