On the limited information we have I would tend to agree with that conservative estimate for the entirety of the interval. Particularly where only Chalcopyrite is present you will see the grading drop down to around 0.5%. However, we will have zones well well above that, just a question of how large and continuous they are.
In my opinion, the upper zone of bornite is key prior to hitting the pervasive chalcopyrite at 1,033m as there appears to be limited chalcopyrite. If the zonation pattern holds true and bornite at the upper levels is uniform across the interval from ~970m to 1,033m (approx) this is what will drive the high grade as it increases the Cu factor by two. If you look really closely you will see it is not just bornite veins/stringers but smaller disseminations consistently throughout the granite which is key.
Further, the bornite is clearly present within the 1033m zone which is also promising. My eye could be wrong and it is hard to see but I think I can spot some minor chalcocite looking mineralisation (although i'm sure that would have been announced). There is also a very dark green/black looking mineral which is hard to make out - I have my thoughts on it but would be interesting to know what
@WhatLiesBeneath29 thinks.
One key piece missing is that we haven't seen mention of the massive and fine/medium milled hematite breccia that you see mention of at OD, ODW and Carapeteena. This hosts the high grade intersections and you can often see the sheen with the fine grained sulfides disseminated consistently throughout the material. This indicates to me we may not see the super high grades in the granite. But given BHPs commentary on the ODW find and the presence of bornite as a pathfinder, I think CHK are very very close to finding it.
BHP drilled AD22 which was declared their discovery hole. This hit altered granite with bornite and chalcopyrite and graded 0.52%. That needs to be understood in order to manage expectations around the result. Anything better than that is big. AD24 was another hole that stayed in the altered granite. In my view they are the best guides as to what grades to expect. Of course, the assays could tell a vastly different story given varying levels of alteration so it is all guesswork at present - just trying to go off hard information.
The other factor which doesn't really stack up is the absence of a large gravity anomaly. However, at that depth it may not be the most accurate measure and the key is that HWDD04 is smack centre in the MT anomaly in terms of location and depth.
Good luck to all.
(20min delay)