Find the sweet spot - Optimise the grinding circuit throughput of a gold processing plant.

Background:

SAG Mills and Ball Mills are the work horses of most mineral processing plants. Their purpose is to reduce the ore to a size that allows separation of the valuable minerals (e.g. gold) from  the waste rock. The yield/recovery of gold from downstream processing stages improves if the solids are ground finer in the grinding circuit. However, this requires more power and slows the overall throughput. A 5% improvement in throughput would produce an additional 25,000 ounces of gold per year ($44m AUD)

Ideal Outcome:

The finest grind size for a maximised consistent throughput rate while energy use is minimized. 

Full Challenge descriptions:

https://drive.google.com/folderview?id=0B3V1hH4D_JtmalpqSnlhZDN1dW8&usp=sharing