Production-scale semi-autogenously grinding (SAG) mill.

CSIRO's Mr Kevin Davey installing accelerometer modules on a production-scale SAG mill.

Protecting mills from the daily grind

A new technique to help reduce internal damage to autogenously and semi-autogenously grinding is in the final stages of development.

1 November 2007 | Updated 14 October 2011

Project summary
Outcomes
Current activities
Project sponsors

Project summary

The autogenously and semi-autogenously grinding (AG/SAG) system, helps reduce internal damage caused by the tumbling motion of rocks and balls inside mills.

It is based on acoustic emission sensor technology and interpretation software. It uses acoustic waves to cut through the noise generated by heavy machinery and ‘hear’ how well it is running.

The system was developed as part of an industry-sponsored Australian Mineral Industries Research Association Limited (AMIRA) project.

The AG/SAG system uses acoustic waves to cut through the noise generated by heavy machinery and ‘hear’ how well it is running.

The technique uses an on-line analyser monitors passive acoustic waves, at frequencies in and above the human hearing range, to sense the condition and state of processes within a rotating mill.

By providing reliable, real-time information about the motion of material inside mills, the analyser has the potential to save mining companies millions of dollars in costs associated with internal wear and tear.

Outcomes

A team from CSIRO has now installed a continuously powered on-line vibration monitoring system at a full-scale production semi-autogenously grinding mill at an Australian mine.

It is the first unit to be permanently installed at a mine. It follows successful short-term prototype trials at six mines worldwide.

The monitor is able to locate the points where tumbling material has a direct impact on the mill’s lifters and liners, causing excessive damage. This damage results in more frequent shutdowns for maintenance to replace worn or damaged parts.

A key benefit of the new technology is it allows operators to:

fine-tune mill operations to minimise the occurrences of direct liner impacts
extend the life of the liners and lifters.

Stopping a mill and installing new liners is a very expensive operation. This technology reduces the number of stoppages required per year to fit replacements.

The CSIRO team also designed the monitor to enable it to provide information about:

the load being ground inside a mill (including amount and particle size of the rocks)
how this changes as a function of time.

The prototype system was powered by batteries, but the CSIRO team developed an inertial power supply for the permanently installed system. This uses the mill’s motion to generate continuous power to the transmitting unit mounted on the mill.