ARRs general thread isn;t the place to examine the risks and...

ARRs general thread isn;t the place to examine the risks and assumptions for HCk, so as time permits, I'll just feed my thoughts out into this thread.

One of the critical flaws in the SS was to ignore actual test data results and instead rely on made-up high recoveries to leach liquor of Dy & Tb. The temptation is self-evident... much higher revenue and importantly better chance of US Guv subsidies as the US desperately seeks supply chain security of DyTb (given NdPr is ubiquitous in most RE deposits and is not the big supply risk issue).

Data and assumptions for DyTb recoveries are based largely on Yttrium (Y) as the indicator RE element, given Y is a HREE in much higher in concentration and thus more accurately measured as a proxy for other heavies like DyTB.



I'm, sure you all read the US SS Tech Report and saw that ARR chose to assume more than double the recoveries of Dy&Tb vs actual test data. One issue at <30% recoveries to leach liquor form the concentrate feed is that the cost of budling and operating Dy &Tb recovery circuits just isn't economic at some point and thus it makes more sense to just let the small amount leached go out to tails. The consultants opined (guessed) the problem was analysis error and recoveries would jump higher after more robust tests on larger ssamples were conducted...


I've pointed out that previous work on rare earth extraction form allanite by direct acid leach (Jan 2024 paper recently promoted by ARR release in MAy'24) demonstrates lower recoveries for LREE (eg NdPr) than HREE (eg DyTb)...


But there is another possible explanation. Y & HREE are often preferentially enriched in zircons, which also partially flow through the leach concentrate as heavy, sometimes paramagnetic minerals. Google this and there are numerous studies that find this for magmatic zircons. The possibility then for poor DyTb acid leach recoveries may wlll be due to the Y&DyTb being is locked in zircons as well as lower HREE recoveries in general. Don;t take my word for it though... read what is written in the SS report.