Heard there may have been someone who didn't quite understand what I meant by recoverable grade curve.
Wrote the above on the phone app last night and what I wrote got deleted twice while switching windows rather than risk it being cleared a 3rd time I posted without a direct link to the source preso, link below. I may also have rushed it a bit so it didn't end up being very clear perhaps.
Firstly, to help clarify, the recoverable grade curve as per above was referring to the relative curve recoverable grade at different depths/weathering zonations within the depth and weathering profile as opposed to a per element average across selected samples. This will look different for every deposit, but Aclara in the below have compared themselves directly to Chinese Ionic Clay deposits and the Makuutu deposit metallurgy also shows similar signs. The ppm's and distribution may be different but chances are if MEI has an Ionic Clay deposit on their hands (which I think they do) that the curve will likely imho look very similar. In the metallurgy report there were some samples from 0 metres, but only 1 from 19-20 m, good average overall with those included but no clues provided as to how weathered the bottom of holes were or not.
Link to Aclara preso (slide 9):
https://uploads-ssl.webflow.com/6267a587be31507747a1c8b6/6372b22de0bc15297c1bfade_Aclara%20-%20Presentation_Long.pdfSecondly, checking the MEI announcements around my theory re power augers and drillability, does look like there may indeed have been some holes abandoned early. The good news is that a lot of holes did go went to 20m, or they encountered groundwater that made auger drilling impossible. They do have photos of every single meter, so MEI knows what the last couple of meters look like but have elected not to share representative examples thereof. Not a criticism, just a fact. Total depth could be anywhere from EOH +1cm to 100m, their conclusion is that they don't know and want to drill to find out. Perfect, that is the only one way to actually find out.
Lastly, checking the exact wording used, MEI have used "saprolite/clays" in a lot of places, but at the same time they say the below, i.e. that matches to the "B" section in the diagram on my previous post. We simply do not know where the curve will taper off as MEI haven't offered many clues I could see, the biggest clue is the cross section as to what they think, i.e. CDM-150 for instance they are thinking is closer to the base rock possibly due to what they see at end of hole? Long story short to the point of the post I was responding to last night, hints around the weathering profile would be good. i.e. REE mineralisation starts at 0m in a lot of holes but the photo below also says 1-3m of soil which on the recovery grade curve would not be generally expected to perform well.
Instead of saying simply "Saprolite/Clay" below the soil level I would love to see something like the below breakdown when they show the results of the upcoming drilling as that likely corresponds to a recovery grade profile. For now the best guess as to what MEI are thinking is the cross-sectional view above as to what they're thinking but we will find out hopefully in the next month or so.
(20min delay)