The Announcement states -The ball mill was not able to be tested...

The Announcement states -
The ball mill was not able to be tested under full load until earlier this week, after the ultrafine grinding mill was functioning at full power and capacity. This only occurred recently after a lengthy delay waiting for the supplier to provide a larger ultrafine grinding mill shell.
"The problem with the ball mill is that windings in the electric motor are overheating as load is increased ". The problem will best be resolved through the installation of a suitable new motor.

Either - 1, there is a failure with the internal windings which is rare with new motors and unpredictable, or - 2, it is undersized . Motors overheating are generally an indication of overload conditions,this can be caused by a mechanical failure or more likely it is just too small. Hence the necessity for replacement.
This appears to be the second under specified, undersized design issue for this plant.
May there not be anymore !!!!!!!