@Kipper01 Figure I'd reply on the general thread, but the most recent timeline I have seen for the Phase 2 met work is the June quarter (nothing more specific than that). There are only 5 weeks left in the June quarter and Rob seems to be good at meeting timelines, so could be next week or in 5 weeks.
There are a few parts to the Phase 2 work - leaching optimisation, impurity removal/MREC and comminution testing. Not sure if they are planning on releasing these in separate announcements or one large one.
The Phase 1 work identified three areas for leach optimisation:
1. Increase the particle (crush size) = theoretically lower iron and aluminium extraction and acid consumption from less surface area for these unwanted minerals to react with the acid. I've assumed they will go for a more costly HPGR crushing process like Apollo Hill's PEA (~4 mm crush size) but per the Sydney RIU preso looks like they are trialling pretty coarse jaw crush sizes of 10mm and 15mm. If they can pull those off that has some notable advantages for heap processing (higher heaps, reduced crushing CAPEX, reduced crushing OPEX).
2. Increase leach pH = lower Fe/Al extraction and acid consumption but likely will also have reduced REO extraction. Where the tradeoff lies is up to the economics and REO pricing assumed. Most interestingly to me, they are trying pH 3. That's the same pH as is accepted as "ionic clay" processing, and Aclara Resources Penco in Chile use pH 3 for their ionic clay. It would be very interesting to see them pull off a pH 3 heap leach because then you start getting both the benefits of huge tonnage heap processing over clay tank and filtering (like the ionic plays) on CAPEX/OPEX whilst getting the ionic clay super low reagent OPEX.. We could end up getting the absolute lowest OPEX per tonne ore in that scenario.
3. Increase residence time = possibly increased REO extraction but we don't know if the REO extraction was already maxed out in the Phase 1 work. Ultimately need to get a long enough residence time that gets the REO extraction to plateau, but very importantly, heap leach residence times can be years so it is whatever it needs to be.
The comminution testing will give us an idea on how hard or soft the ore is. The softer the ore, the more throughput you can run on crushers (less CAPEX) and it costs less to crush the rock. If you are trying to go for a massive tonnage (20 mtpa+) low cost process all these little things count.
Thanks again.
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