Fill Analyzer.

The Fill Analyzer turns a SAG mill’s own noise into a live measurement. A ruggedised vibration and acoustic sensor mounted on the mill shell picks up the impact signature every revolution — each cascade and cataract leaves a characteristic pattern in the signal. On-board inference converts that pattern into the two numbers a grinding operator has always wanted at a glance: how full the mill is, and where the falling charge is landing.

What it measures

• Fill percentage — the total charge (rock plus balls plus slurry) as a fraction of mill volume, updated every few revolutions
• Toe and shoulder angles — the position where the rising charge leaves the wall and where the cataract lands, in degrees from top-dead-centre
• Impact offset — how far the cataract is landing from the optimum toe position; positive means overthrow onto bare liner, negative means underthrow into cascade
• Impact energy — peak intensity per revolution, the leading indicator of liner wear
• Rhythm stability — cycle-to-cycle consistency of the signature, an early flag for charge segregation, grind-out, or overload

How it changes the circuit

Most SAG mills run with fill inferred from bearing pressure and motor power — both of which lag reality by minutes and drift with wear. With a direct read on fill and impact angle, the MPC can hold the charge at its productive optimum instead of retreating to a safety margin, and can react to hardness shifts before they show up in the load cell. The same signal keeps balls from smashing bare liner, extending shell-liner campaigns and cutting the noise floor of unplanned maintenance.

Deployment

Non-invasive: the sensor bolts to the mill-shell exterior and needs no penetration, no shutdown, and no re-plumbing. Edge inference runs on hardware supplied by Aeterna — no cloud connection required during operation. The signal is exposed to the DCS and historian as standard tags (fill %, toe, shoulder, impact offset, impact energy), and feeds directly into the process model and MPC alongside the other smart instruments.