Ann: West Arunta Project - Luni Assay Results, page-439

Thank you for that thorough analysis salpetie, it really helps with our collective understanding.

As you're aware, although I did categorise carbonatite as a softer host rock, this is only really in comparison to other igneous host rocks in that same family. As a whole though, the igneous rock family is still in the hard category. Now on the point of fresh v weathered, fresh carbonatite is harder than the weathered carboantite because the rock mineral and structural composition has not been altered by weathering processes. It will get harder and more costly the deeper we go, but we hope that this will be counteracted with greater mineralisation.

The figure you point out from May 2023 is a curious one because it shows that well endowed blanket fairly close to surface. This is at odds with the general consensus that fresh carbonatite should contain higher niobium mineralisation than weathered carbonatite because it represents the primary unaltered form of the rock. Chemical alteration of the carbonatite occurs due to exposure to water and atmospheric gases. If the minerals leech and and redistribute, this is where we will see lower mineralisation (perhaps what our neighbours are seeing with their lower grades - I haven't paid much attention to their geology). I would be curious to find any mapping of water tables for the region, as it may give us a clue as to whether we will continue seeing fresh carbonatite below a certain depth, or potential for breaks in mineralisation due to alteration, we don't want the latter. I suspect this will be hard information to come by, if it exists at all, given how little exploration has occurred in the region. Further drilling and the met studies will likely elucidate most of the above.

Regarding climate of the Gibson Desert. The Pleistocene period (2.6 million to 11,700 years ago) saw many changes in climate in the Gibson desert and that would have affected the availability of water in the region. Ancient river channels, lake bed sediments, and fossilized remains of aquatic organisms have been found in the Gibson desert, so it isn't a stretch to assume that at some point Arunta was similar to Araxa. Of course, these geological processes take thousands and millions of years as we can see above. The potential for weathered rock can exist below fresh rock in certain geological settings where deep weathering profiles emerge. If we go back to the Paleozoic and Mesozoic periods (541 million to 66 million years ago), when Australia was part of the super continent Gondwana, long periods of aridity followed by humidity emerged. We don't have specific data on this, but due to science we know that climate is not static. This could lead to that layered weathering/fresh rock I mention above. We do know however that the Pleistocene era had repeat glaciation (drier temperatures in the Gibson) followed by interglacial periods (where humidity was predominant). Again, the varying temperatures there led to fluctuations in wetlands and water access. Given that central Australia still does have some lakes, It isn't hard to accept that with lower temperatures and or more humidity, that the landscape of the desert has changed at some point in the last 541 million years, and along with it the geological processes at play.

The LYC announcement gives more credence to what we may see here. It can become a dogs breakfast though because several theories about the mineralisation profile can run side by side until we really do further drilling and met studies to understand the geological constraints, viability etc. One has to logically follow the other. Without good recovery, we don't proceed to deeper drilling, and without the deeper drilling, we don't get to understand the nature of the mineralisation in the Luni deeps. We still understand so little about the area and this is what makes this exciting.