Expert control for high pressure grinding rolls (HPGR) improves productivity for South American copper miner

The customer challenge

The main challenge for the customer, a South American copper miner, at the initial stage was to keep a healthy level of inventory in the feeders to ensure a consistent feed between the rolls. A layer of ore between the rolls helps the compression forces to break the particles more effectively and consequently a softer ore will be fed to the next stage.

To keep this layer of material at its desired level the operator must constantly monitor the level of the four discharge bins, making sure they don’t get too full (this can cause the feeder to get stuck between the discharge bins) or too empty (causing the rolls to stop resulting in a decrease in overall throughput). The process to fill the bins happens relatively quickly and the operator must monitor other equipment in the area at the same time, making the task of keeping everything at an optimal operation daunting.

Another challenge with the HPGRs is to maximise the comminution energy by increasing the power in the rolls. With hardness changes it is necessary to adjust the pressure dynamically to produce a softer ore for the ball mills.