While at Fosterville I heard whisper of some innovative work in the treatment plant and caught up with Marcus Binks. Marcus is known for his ability to find gold in mud, something that came in handy for him at the recent Australasian Gold Panning Championships where he took out the title.

The Fosterville Gold Mine uses bacterial oxidation to treat their refractory ore and they have always had issues with preg-robbing of gold in their CIL resulting in relatively low recoveries. I don't pretend to understand the intricacies of CIL, nevermind preg-robbing (nasty term that!) but Marcus is prepared to explain the system to anyone who understands their hydrometallurgy better than me.

Fosterville have developed a heated leach circuit to treat their leach tails at a rate of 11-12t/hr. The system uses LPG to take the slurry up to 70 degrees and somehow, that frees up as much as 50% of the remaining gold in tails which will give Northgate an extra 35,000oz over the current planned mine life. Marcus believes most other bacterial oxidation plants will be able to benefit from the work carried out at Fosterville and he intends to present a technical paper on the subject sometime in the next twelve months.