Weekend musings....
Not certain if you refer to lateral or vertical variations for mineralisation and RC.
Near surface lateral dispersion of high grade Nbx does appear to be minimal. There may be, probably is, a wider geochemical dispersion but that is not likely to be not going to be economic at grades mostly below 2000 ppm Nbx.
The process of forming high grade supergene blankets?
1-10+% sub horizontal zones with halos of decreasing grade around them.
Limited
detail geochemistry available for Luni with aggregated assays the norm except for the 2022 holes
where 4m results were given. Subsequent 1m results were
aggregated e.g.
| Hole ID | From | To | Nb2O5 | P2O5 | assay m |
|---|
| 1 | LURC003 | 44 | 48 | 1.54 | 13950 ▪ | 4m |
|---|
| 2 | LURC003 | 48 | 52 | 0.58 ƗƗƗ | 1920 ▪ | 4m |
|---|
| 3 | LURC003 | 56 | 60 | 0.96 | 1100 ▪ | 4m |
|---|
| 4 | LURC003 | 60 | 64 | 0.45 ƗƗƗ | 570 ▪ | 4m |
|---|
| 5 | LURC003 | 64 | 68 | 0.07 ƗƗ● | 340 ▪ | 4m |
|---|
| 6 | LURC003 | 68 | 72 | 0.07 ƗƗ● | 550 ▪ | 4m |
|---|
| 7 |
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| 8 | LURC003 | 40 | 47 | 3.47 |
| 1m |
|---|
| 9 | LURC003 | 41 | 46 | 4.38 |
| 1m |
|---|
| 10 | LURC003 | 44 | 45 | 7.5 |
| 1m |
|---|
| 11 |
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| 12 | residual |
| 6m | 2.8 |
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|---|
Above a source or moved? Likely above but don't know..yet. Probably reworked multiple times during the ongoing weathering process which has gradually reduced the surface to current levels from who knows what. [REEs at Mt Weld are a better documented example as might be Araxa]
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Primary zone mineralisation at Luni is locally high grade but relatively sparse - this may change locally as carbonatites are variable (e.g. Mt Weld/Araxa/Phalabora as major examples)
The sections below may, or may not, be representative. There has been significant drilling since.
Post with Mt Weld as an example of weathering and fresh rock distribution of REEs. Mt Weld does have a resource of some 40 Mt of 1% Nbx tucked away in its NE quadrant along with significant phosphate. Up to 40% REEs tends to attract the first attention and lion's share of the exploration/mining budget so these peripheral deposits and any other subsidiary REEs go on the back burner.
Araxa information and Nbx profiles.From the post are these profiles.
There is generally more consistent high grade Nbx in the weathered zone vs fresh rock. Difficult to compare Araxa V Luni fresh rock assays but the impression I get is Araxa's may be consistently more elevated. DYOR.
Araxa V Luni
- A 90 Mya... L ?1300Mya
- A circular plug....L intrusive but more "stretched out" perhaps with Emily and Green being wings to the "whale". Form may not be too significant.
- While the shape of Araxa may not be critical the presence of a ring of hydrothermal alteration around it may have produced a near dam effect which may have led to weathering products being more contained.
- Both are part of larger fields of carbonatite/Alkaline intrusives.
- Weathering has been much more recent at Araxa and is still ongoing as it is at Luni albeit at a slower pace for the latter.
- A is probably larger than Luni if the recent MRE is any guide in the west Arunta.
- A is a zoned intrusive - perhaps more so than Luni though drilling and data are still to come which IMO will reveal some additional complexities.
- Both have Nb/REEs/phosphate which seems to be a common theme.
- Araxa and Luni both have relatively shallow high grade Nbx blankets amenable (likely to be) to mining for many decades. 70 years, and many more, for Araxa.
- Share a small Nbx market.......Much been said on this here and on the WA1 site.
- A moot point but the stranded Seis Lagos Nbx project in NW Brazil is arguably larger than even Araxa which demonstrates the likelihood that more high grade Nbx deposits will come out of the recent uptick in Nb exploration
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The above are from a couple of my posts which are marginally easier for me to find in the large amount of those available that give useful information and views about the varying aspects of exploration and possible development.
Even finding my own posts is a chore made easier by a partial archive. AI? Might help.
Not everyone's favourite poster (
@2ic) but does know geol and mining prospects very well. Took a few minutes
but found one post on Mt Weld vertical variations weathered to fresh - for REE's- that shows what is available.
(20min delay)