Response below in part to Inky Basically a draft below about...

Response below in part to Inky
Basically a draft below about weathering and grade distribution. Take with a pinch of salt as many variables come into play.

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First Sentinel update for RC site prep and some drilling at Green using sections from this announcement for context of the interpretation.

Spotted two areas of activity.

• further work in the SW corner of green with probably some 4 or 5 new sites. Most drilled?
• Central Green with 10 sites interpreted. One site drilled?

Solid magenta 10-15/9 with two previous (open circles).

Detail on SW corner



Sectional interp. Assume RC holes drilled grid south at -60 degrees.
Good test to see what, if any, NS continuity of mineralisation in hole 489.



Section 2 updated but apparently only one hole. with inclined A/C hole 321 reducing/eliminating the chance for a northern extension.



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Central area
Infill with probable inclined RC pretty much as would be expected. More site prep and drilling likely in NE and perhaps elsewhere on Green between sections 2 to 5. 200m infill between sections 5 and 6 would be a reasonably positive sign (ditto 4-5 and 6-7) though do not expect game changers.


Section 5


Section 6


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@inkblot this is a complex question.

Complex mainly because weathering profiles are complex products from a dynamic process. Dynamic in geological time with weathering probably happening over the last 10-20 million years in particular.

Need (simplistically)
Source of mineralisation. Carbonatite in this case. No Nbx; or Au; or Cu in fresh rock then no potential ore at surface.
Time
Fluid movement to redistribute mineralisation
Preservation

Aileron is 'blessed' with multiple carbonatites which contain Nb/REE/phosphates at least in variable amounts in the primary zones as shown by a few deeper holes and perhaps more so with the deep holes at west Hurley.

There was probably Permian Glaciation impact on the area which may have wiped the surface clean some 250 million years ago. Since then the area has likely been similar to much of WA and been relatively stable with only climate variations leading to variable weathering and limited erosion. Local drainages, palaeochannels, cut through some areas and drain into the salt lake systems. Lake Mackay would be a low point for this area with some drainages going into it that might erode some deposits - probably not for Luni etc with much more research to come.



Couldn’t it be possible that the Nb in the upper layers targeted by AC have been leached away in time
Definitely a possibility for leaching. Very likely there have been multiple times when such a process has occurred with the current drill results just a snapshot in what is an ongoing process.
Distribution of mineralisation within the weathering profile is complex. The supergene (?) high grade blankets are at varying depths in the weathering profile. Commonly 30-60m as what may be a perched layer and a deeper zone around 70-100m which may represent the transition zone above fresh rock. Until more detail studies are revealed these are just simple observations without much rigorous study. These depth variations are perhaps more apparent for ENR holes than WA1's at Luni.

IMO Nbx is not too mobile in the weathering profile. At least not in terms of producing wide, strong, lateral dispersion. High grade zones may be forming from zones of weathered, near insitu, primary elevated grade sites with a concentrating factor improving grades to those seen in recent drilling.

The cut off for reporting grades (0.2% Nbx) tends to support the above statement on the broad scale (+-200m). Locally might be a different story.

and that RC drilling into the rock below would show good economic readings of Nb all over the targeted areas?
Unlikely IMO.
Much less likely that deeper RC drilling will give improved results IMO. Aircore drilling is generally done to easy refusal which is likely to be the transition zone to fresh rock.

RC can penetrate into fresh rock where there is primary mineralisation that will reflect the "original" mineral source. There are likely to be high grade zones in fresh rock which will be much more difficult to define, in most instances, IMO.

There have been posts on this in past for both ENR and WA1. Metallurgy for weathered and primary mineralisation is going to be different with the latter likely to be more complex and expensive to process on top of the increased mining costs.




Could that be the reason why ENR is proceeding with RC in the same areas?

ENR always planned to use aircore to define zones of mineralisation for RC follow up. My rough sections show, IMO, how this is happening at Crean west and now Green. Probably will extend to Emily next and perhaps Joyce. Hopefully in other areas where wide swath aircore coverage has been employed and yields a few targets.

RC will drill further into bedrock and show the distribution of mineralisation especially where aircore holes stopped in mineralisation. As an example the diamond tail for LURCD042 showed this - may only be a one off but not uncommon at the interface with fresh rock.