Problem

Currently, the Grinding Application is able to do Mill Overload Predictions: predicting whether a mill overload situation might happen in the next 10 minutes. It does this by predicting the Mill weight and power usage over the same time period. Overloads are predicted by comparing the weight predictions with a manually entered weight threshold value, and if the former value is higher, the Application predicts that there will be an overload.

The fact is, though, that this threshold weight changes all the time, as the mill feed and operational conditions change. What if we had a way to determine this threshold weight, and pass us it for Mill Overload Predictions?

Our Solution

During an overload scenario, the mill power usage goes down while the weight increases - as can be seen below:

Figure 1: Power-Weight curve for data during a mill overload event

It can be observed that a negative parabola can be fitted to determine (for a given time period) at which mill weight the power begins to go drop. This data contains historical information on the weight and power of the mill as well as the current knowledge of these sensors. This is updated in real-time.

As a result, at every moment, the Grinding Application outputs a Dynamic Overload Weight Threshold. For example, the below plot shows this dynamic weight threshold every minute for the same data:

Figure 2: Line trend showing the Dynamic Overload Weight Threshold

The new virtual sensor gives a more accurate prediction of the weight threshold at which an overload would/will happen. Hence it can replace the manually-set weight threshold used by the Mill Overload Predictions.

Value

The dynamic new weight threshold, along with the Mill Overload Predictions, provides Operators and Metallurgists with a completely automated overload prediction system - updating itself as feed and mill conditions change. This gives operating personnel peace of mind that they will be alerted at the right time before a mill goes into overload - with enough time to make the feed changes needed to avoid a mill stoppage altogether.

For more info, please do reach out to us via Intercom. We'd be happy to help!

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