Good work, not often I see anybody actually digging down into data and evidence to get a handle on what is going on. I refer to A4 as the dome that contains the recent drilling and resource, which has been shown to dip away in all directions by that drilling. The A4 resource announced yesterday by my definition is open at depth, although deeper holes have been thinner and lower grade as I discussed. The new NE drilling looks to be chasing either the deeper strike extension of the A4 dome, possibly offset by faulting to the SE, or another dome just east of this diagram below.
I can't argue that they haven't found something out there, multiple holes suggests something of interest. Neither can we say they have found something even close to economic either. Exploration drilling chases up minor mineralisation and smoke looking for the fire all the time, that's the game really. Given the coordinated releasing of recent high grade A4 results it's fair to assume if they have decent new discovery hole they would have also added that news to the sizzle.
Those new high grade intersections are interesting for a number of reasons. The highest grades occur in extensional quartz veins from what's written, so what strike and dip extent they have is unsure. That the results come from the middle of the deposit and haven't been repeated along strike indicates they might be small 'jewellery boxes' as they say. Nice to have but not necessarily much change to resource extensions. Interesting that they chose to drill two scissor holes into those HG intercepts from the other direction to confirm if they drilled down dip veins or if they represent true widths. Certainly such grades are worth getting a good understanding of and hopefully opening up scope for more to be found.
I'll answer my own question here about the depth of weathering at A4 vs T3. The DFS has a x-section showing that the weathering depth is mostly above the ore at T3 as described in the report. Some low grade mineralisation only seems to sit in the weathering profile, and at <0.3% Cu left as waste I would guess. Recoveries of oxidised cooper ore is notoriously poor, especially when the plant is set up only for a sulphide float process recovery.
At A4 the weathering profile is a similar depth but the higher grade ore sits closer to the surface and is thus oxidised. If this x-section is representative of the A4 deposit along strike, maybe up to one third of the ore will be oxidised to some extent with commensurately lower recoveries. Unfortunate and to some extent reduces the contribution from A4's towards the hub's growing reserve base. Reality may be more or less oxidised high grade than shown in this section though?
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