How a mining company eliminated unplanned shutdowns and saved over $1 million a year

When a gold and copper mine in rural Australia had repeated failures on all of the mill motors that drove production in its grinding plant, a lot was at risk.
The company processes the ore on site, grinding it to a slurry to prepare it for the recovery of gold and copper. When a mill motor fails, the loss of production and the cost of repair have a considerable negative impact on revenue.

Author: machinemonitor®

Repeated failures caused machine reliability headaches

The mill motors were flashing over and arcing on their sliprings and brush gear, putting the safety of employees at risk from flying debris and causing expensive emergency shutdowns. The mine operators had performed limited maintenance, but the work wasn’t documented and the problems continued. Each critical mill motor failure could cost the company more than $500,000 in lost production and another $100,000 to overhaul the failed machine. The company needed a solution that would stop the repeated mill motor failures once and for all.

The mine operators wanted to understand the cause of the problems so they could prevent future occurrences. They began to search for a strategic partner with a reputation for problem-solving and extensive experience in machine asset management.

The site maintenance staff was underestimating the importance of brush principals, namely:

• Never mix brush grades on a single slip-ring
• Always confirm fit and measurements
• Always have a system in place to check OEM-supplied brushes to drawings and specs for compliance
• Never change the load on the motor without considering the impact on the brush system

A one-time fix would solve the problem for the moment, but a change in personnel or simply human nature could cause the problem to re-emerge in the future. A process-based approach was necessary to ingrain proper brush maintenance practices, along with a software solution that would improve lifecycle care of the mill motors.