sulphide versus oxide, page-4

Thanks heaps BT.

I suppose the angle I was getting at is that for the foreseeable future there will be a flotation plant ONLY and yet a mixture of sulphide and oxide available. Mostly separate deposits.

Much as I love the idea of a SX-EW plant with heap leach of oxide ore producing copper cathode, I honestly cannot see it when we are having trouble enough trying to get this small plant funded/started. The capital will not be there in our lifetime I suspect. So my mind turns to how to optimise the proposed flotation plant/process to handle both sulphides and oxides, both of which we have invested heavily in exploration to find.

The referred scholarly article published as recently as 2008 suggests a way.

It does discuss the flotation of copper oxides as a stand-alone process. It points out the wide range of collectors (chemical additives) evaluated, those materials that adhere to the copper material and cause it to float selectively to the surface as froth. None are all that great when translated from the lab to the plant situation.

There is also mention of the "controlled potential sulphidisation" CPS where the surface of the oxide minerals are sulphidised by an agent such as NaHS, to trick the process into thinking it is processing sulphides, but again a highly controlled lab situation is poorly reproduced in a plant and it is not too successful.

What the paper proposes and has apparently tested very successfully is the introduction of n-octyl hydroxamate as a complementary collector to the traditional sulphide collectors (the ones AVB would normally use). They then claim that such a flotation plant can process a blend of sulphide and oxide minerals to produce a saleable concentrate. One that meets spec on minimum copper and sulphur.

Such collectors have been know for decades, but this AM28 apparently is special, having a particularly effective stereochemistry... and hence surface binding ability I suppose.

The main claim is this "N-octyl hydroxamate collectors such as AM28 can be used successfully to recover the oxide mineral component in mixed copper sulphide/oxide blends without reducing the recovery of the sulphide minerals". Plants are using it very successfully.

OK... applying this to AVB.

The DSO at AS can be mined on the side Very profitably, plenty of supervisory staff avaliable. Then in the course of mining this shallow deposit and selectively extracting it, there may be the opportunity to selectively mine, blend and stockpile sulphide/oxide ores. Have it all ready to use in the new flotation plant. To work up the plant. The timing would be perfect.

Thus for as long as you can, work with a 70/30 mix to use up the troublesome oxides. Get value from them, and effectively extend mine life.

Sure it would be easy to just do sulphides; who would raise their hand and complain...but this proven approach presents a way of maximising the economic value of AVB's overall copper resource.

You CAN process a blend of sulphides and oxides. No need to turn our backs on the oxides.

A voice in the wilderness I know :))

... but nobody is going to stop me from suggesting it!

Cheers, PP