A while ago they priced upgrading the Tukubianca mill.$60m or so...

A while ago they priced upgrading the Tukubianca mill.
$60m or so was mentioned.
If you consider expanding a plant someone holding tight purse strings is going to naturally ask - What is the ideal plant? and What's the payback period?
Until you know exactly what you plan to feed it and for how long you are planning to see the payback you know very little and just throw money at a best guess.

So,
Firstly they have taken out whatever costs they can with the existing plant with a rather short immediate payback via cost reduction resulting in a natural hedge against future Diesel cost rises by eliminating 38 million ltrs of diesel from their cost side per annum.
Now they are establishing the forward profile of future mill feed over all sites of at least a 10yr time frame if not more.

IMHO The next step is upping the milled yield from 86% to nearer 90% or better by improving the feed profile or refining the plant on that basis of the ore they know they have ahead.Is it residency time,oxygenation circuit or UF grinding and to what point is either a logical viable option over the perceived future life of the plant feed.

WB was asked once in an interview about refractory ore.He said which sort?
The ORE you can manage by UF grinding is OK the other stuff I'm not interested in.From memory I think it was because there were too many processing variables to manage.

I suspect we are seeing a very systematic approach and once a 10yr feed plan is in place an upgrade of both the Tuka Mill and improved yield yet to come.
at 90% that would be an extra 4koz or $12m per year from the same existing plant feed and grade.