Ball Mill Rana Gruber
The ball mill at Rana Gruber. Photo: Rana Gruber

Major savings through route-based condition monitoring on ball mill

Using the handheld instrument Leonova Emerald and DuoTech accelerometers, Norwegian mining company Rana Gruber monitors the mechanical condition of the production-critical ball mill in this case study. The planned replacement of a damaged main bearing, detected through route-based measurement, saved the company significant amounts.

Ball mills are a low-speed application (typical rotational speed is 10-20 RPM), where bearing damage can be challenging to detect. Condition monitoring of the ball mill began in December 2016 and right from the start, the readings indicated potential damage on the output main bearing.  

As the months passed, the readings remained at a fairly high but stable level, while the BPFO values showed an increasing trend and clear BPFO matches. When the bearing was replaced during a planned maintenance stop, outer race damage was confirmed. 

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Case Study
Filename/description Language Size Modified
CS_021B_Ball_mill_RanaGruber_NO.pdf English (United Kingdom) 910 kB 11/8/2018
This case study describes the detection of bearing damage on one of the main bearings in a 60 ton ball mill.

Solutions for the mining industry

The mining industry is a heavy industry where condition monitoring equipment must survive mechanical and environmental forces.

Leonova Emerald

Leonova Emerald® is a portable instrument for industrial maintenance. Ideal for daily use in rough environments


The DuoTech® accelerometer is a single transducer solution used for vibration measurements or shock pulse measurements or both in combination.