New method for detection of harmful impacts on shell liners in large grinding mills

Large grinding mills face the problem of high-energy impacts caused by steel balls cataracting against the shell of the mill, with loss of energy and accelerated breakage of balls and liners. Broken liners cause unexpected downtimes affecting the availability, safety and operational costs. In addition, excessive steel and energy consumption cause loss of grinding efficiency and worsen the production expenses. This paper presents a new method based on digital signal processing of acoustical signals collected by a sensor array around a tumbling mill for detecting the level of the harmful impacts within the mill. The impact level allows the improvement of operational control of variables - like the speed- for optimizing the load movement in the mill, reducing, the harmful impacts within the mill. Experimental results at an actual industrial installation are presented.