The last time a knelson was used in the circuit was back in the Oxiana days. It got pulled out during the refurb when Apex took over. There was testwork done at MA's request(and I'm pretty sure it was released to the ASX in some form back when it happened) and it proved exactly what the process team said would happen. Nothing.
Sorry to disappoint you but it won't work because its not the correct tool for the job. the previous knelson was located at the tail, to catch residual gold and sulphides. You stick that thing at the feed end and all you're doing is catching coarse sulphides. Why bother when you've got a flotation circuit that does a better job?
Knelsons are a gravity concentrator, it only works if you have coarse gold amongst a much lower SG medium (ie quartz reef).Some copper/gold mines have knelsons because the gold is coarse, and so they can segregate the gold from the sulphide using a gravity circuit. In the case of wiluna ore, you have fine gold in a heavy (sulphide) medium. Its a refractory ore, any "free gold" is free only in the sense that its not locked up in a sulphide. Its still finely disseminated and will be processed much the same as all the other gold. If it was that easy, you wouldn't need a biox process to begin with. The key word here is "free". It is not interchangeable with "coarse", despite certain board members assurances.
There will always be residual gold at the bottom of a recently emptied biox tank...the whole point of a biox process is to remove the sulphide from the gold..."freeing" it. Stop the process, you have suspended solids dropping out due to being heavier than water. Start it up again and it all goes back into the slurry.
The best thing they can do to improve recovery is to stop messing with it and give it a steady feed. Thats where the feast/starve mentality of the underground production cycle screws it up. The bugs also don't like being messed about like they are every time the power drops out (because ALL the gensets need a serious overhaul). It just doesn't work.
But MA would rather pay consultants to tell him otherwise. Go back over the financials and see how much he spends on external consultants.
I'll also point out that I don't work there anymore, so this latest round of knelson testwork I can only speculate from the asx reports.
DYOR
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