I also forgot to update my disclosure to Held, bought some...

I also forgot to update my disclosure to Held, bought some during last week's sell-down for a seat on the thread (kiss of death, sorry). It's early days and plenty of permit delays and other risks in a structurally broken commodity market, but there's enough potential to be interesting despite the seemingly hard rock, low-grade contradiction. The metallurgy is critical to economics, so that is what I considered first to get a handle before the SS comes out.

You've all seen the process plan, relatively cheap, clean and reagent free concentration of alllanite into the final leach concentrate. This style of gravity concentration is tailor made for scale, except the market is small and downstream REO refining is not great scalability. The question is, what happens to the leach feed con when the ore feed at the front is doubled? If the weight pull doubles to 14% with double the feed grade(ie con stays 35,000ppm) then there is only a saving on lower tonnes mined and smaller plant to build/operate to produce the con. If the leach feed con stays 7% weight putt but doubles to 70,000ppm TREE, there would also be a tremendous leaching opex savings (higher con feed grade, lower the size, capex and opex of leach plant).

The idea is to maximise recovery of allanite (RE) to the con, while minimising silicate trash and lowering the con TREE grade. This means choosing the best magnetic intensity of the WHIMS unit (wet high intensity magnets) to concentrate the final con. The Mar'23 MRE gave us a chart for this, and pictures of the con, demonstrating the lighter colour as more monzonite silicates are dragged into the magnetic WHIMS fraction with higher magnetic intensity.


New met work has defined finer size feed and better trash rejection pre-WHIMS such that the con is 35,000ppm TREE from a ~3000 TREO ore feed, but I suspect something around 6000 Gauss Mag was the sweet spot for recovery vs grade. If the costs of mining and grinding are low enough vs the cost of leaching, it may even make sense to upsize the front end plant and take a lighter cut (lower intensity magnets) for a higher grade leach feed con?

Anyway, reality is some non-mag silicate trash is 'entrained' with the magnetic allanite and makes it into the con unfortunately. There is every chance that higher grade WHIMS feed performs better and the final con separates out twice as much allanite but less silicate trash. Allanite is ~15% of the con at 35,000ppm TREE by my calcs, so double that to 30% allanite with double the head grade only needs to reject ~15% more silicates from the con to indeed double the con feed grade to 70,000ppm... There should be a large uplift in leach feed con grade UNLESS the allanite is ubiquitously intergrown some silicates at 150micron grind and <85% silicate levels are unavoidable?

I don;t think so. This image shows that at <212micron, >106micron grind (lets say similar to the 150micon met update Jan'24) that 18% of Allanite is liberated and pure, 52% is liberated, free and almost pure, and 15% is liberated but not pure. Comapre ot the picture above from 500micron grind, and depsite the grind size difference, it's obvious that the allanite has a large degree of liberation/purity, and that the vast majority of silicate trash in the leach feed con is 'free silicate' minerals entrained into the magnetic cut. It seems unilkely, imo, that higher allanite grades in the mine ore feed will translate to proportionally higher silicate trash in the leach feed con... that is, leach feed con should raise in grade with higher ore feed grade even at the minor cost of some recovery.

Logic can only take us so far, maybe there will always be 85% non-mag trash silicates entrained with the allanite regardless of the WHIMS feed grade, and 35,000ppm leach feed con is the max possible? It was interesting they chose to report the met work using a 3000ppm ore feed example given they knew 6000ppm ore is abundant... hint that 35,000ppm con is the best they can get, or a head fake leaving upside post scoping study so they can come home with a wet sail?

Will be interesting to watch...