SDG – Technologies


The Barrick Loulo Mine in Mali experienced a large number of failures on their Mill gearboxes as a result of high starting torque spikes.

The Starting Torques were more than the maximum allowable limit of 120%. The torque rise in the Critical Area were dangerously high and the Shorting Torque Spikes were more than the maximum allowable limit of 200%. 

This resulted in yearly gearboxes replacements on the primary and secondary Mills at a great cost.


SDG replaced the existing LRSs with three high turndown ratio ALRSs, fitted with heaters, coolers and integrated     Condition Monitoring, Protection and Control systems.

Project outcome

  • No gearboxes have failed since the ALRSs have been installed.
  • Starting torque spikes are kept within acceptable limits. 
  • The mills are started at lower torques (near 100% rate torque) without stalling.
  • The startup torque is controlled by controlling the electrolyte temperature.
  • The number of allowable starts per hour have been increased. 
  • Barrick also placed an order to replace two of their Tongon mine’s LRSs with ALRSs
Fig 1:  Start-up Torque Old LRS VS new ALRS Mill 1 


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