Monitoring liner wear in industrial mills

A method of monitoring liner wear in a mill, the method comprising:

• propagating shear ultrasound waves in the elongated element to a distal end of an elongated element, the elongated element deployed through an opening in a shell of a mill into a liner of the shell so that the distal end of the elongated element is impacted by charge during operation of the mill, the elongated element wearing at a same rate as the liner under conditions within the shell;
• determining travel time of the shear ultrasound waves to the distal end;
• determining whether the travel time has decreased since a previous travel time determination;
• determining a decrease in length of the elongated element from a decrease in the travel time of the ultrasound waves to the distal end;
• and,
• relating the decrease in the length of the elongated element to liner wear.

A method of monitoring liner wear in a mill comprising:

• providing acoustic markers on a liner bolt that affixes a liner to a shell of the mill, the liner bolt having a distal end that is impacted by charge during operation of the mill and wears at a same rate as the liner under conditions within the shell;
• propagating shear, longitudinal or another type of ultrasound waves in the liner bolt;
• tracking echo signals reflected off an extreme end of a wear face of the liner bolt at the distal end of the liner bolt and off a current distalmost acoustic marker;
• determining travel time of the ultrasound waves to the extreme end of the wear face, and determining a decrease in travel time to the extreme end of the wear face in comparison to a previous travel time determination of the ultrasound waves to the extreme end of the wear face;
• determining a decrease in length of the liner bolt from the decrease in the travel time of the ultrasound waves to the extreme end of the wear face;
• and,
• relating the decrease in the length of the liner bolt to liner wear by
• determining when a waveform of the echo signal reflected off the current distalmost acoustic marker starts to change due to a change in shape of the current distalmost acoustic marker caused by wear of the liner bolt,
• determining travel time of the ultrasound waves to the current distalmost acoustic marker,
• determining distances from a proximal end of the liner bolt to the extreme end of the wear face and to the current distalmost acoustic marker,
• determining liner wear profile from a difference between the distance from the proximal end of the liner bolt to the extreme end of the wear face and the distance from the proximal end of the liner bolt to the current distalmost acoustic marker,
• estimating actual liner wear profile from the determined liner wear profile until a next distalmost acoustic marker is reached due to wear of the liner bolt,
• updating liner wear profile information each time the liner bolt wears down to one of the acoustic markers as indicated by a change to the waveform of the echo signal.

An apparatus for monitoring tumbling mill condition and tumbling mill operation condition comprising:

• means for acquiring ultrasonic waves for rod wear measurement and audible sound waves for detection and measurement of charge impact with a same data acquisition device;
• means for measuring angular position of the tumbling mill at each moment impact data is being recorded;
• means for conducting the wear and impact measurements at a plurality of locations;
• and,
• means for supplying electric power to the apparatus.