I don't like saying a lot when other lithium plays are having issues, but I thought I would re-post these embedded post from a while ago around crystal size, coarseness and deleterious elements in the lattice as it relates to AVZ and potentially how that may help out a process flow sheet so that it operates at spec - Post #:
40459181 and Post #:
40476332.
Especially in understanding why AVZ has higher recoveries in the DMS stage than other hard rock plays, meaning AVZ is not overly reliant on floatation to achieve significant output from the nameplate capacity it installs (i.e. been for example a 5 mtpa ore feed configuration if that is what the DFS uses, noting the May 2019 SS for AVZ used a 5mtpa configuration etc), and why it can start production with a DMS option only (and then retrofit floatation later on). The reason, for example IMO, why AVZ has a large recovery in the DMS stage (which happens before floatation) is because the crystals are large and coarse, and the deleterious elements are not significant in the lattice. (And obviously the Li20 content for AVZ at Roche is very good in the ore.)
Another way to put it, the finer the spodumene or less coarse and smaller the crystals, the greater is the need for project economics to be driven by floatation circuits IMO.
A DMS option requires a crush size of say 3.35mm or 5.6mm (not sure which setting AVZ will use but those mm come from the HGPR/crushing circuit before the DMS stage and what AVZ have been using in recent METs), whilst floatation input feed is (using MLL's Sept 2019 Ann as an example) is in the region of P80 of 106 microns which comes from the ball milling circuit after the DMS stage but before the floatation stage.
For others, like PLS, where floatation is a key to spodumene recovery IMO the higher the reliance on floatation the potentially i.) higher the likely costs of production IMO and/or ii.) what can go wrong in a process flow sheet and/or iii.) the higher the capital costs for say each 2mtpa ore feed plant configuration to achieve lower operating cost targets (i.e. PLS for example is retrofiting more capex units to increase recovery and therefore as a means to reduce costs, and time will tell how successful that will be).
Whilst, IMO PLS/AJM will provide learning to aspiring newcomers like AVZ (and even MLL) around test test test so that the process flowsheet you install works without a need to retrofit capex, IMO the AVZ process flowsheet will be more simplified than some of the likely process flowsheets (i.e. in terms of number of units at say each stage) of the other hard rock plays, with the exception of Greenbushes I dare suggest, including when floatation is retrofitted to the DMS option. Obviously I am speculating here.
IMO, I also suspect that having a low strip ratio and in effect a
homogeneous deposit will IMO also ensure that for AVZ, when floatation is introduced, that the efficiency of the grinding facility circuit (the SAG) and interaction with the ball milling facility (the ball mill) can be better optimised, noting also the lower amount of ore that goes to that stage for AVZ given the recovery stage in DMS - this article explains that concept
https://www.mech4study.com/2017/10/difference-between-sag-mill-vs-ball-mill.html.
In a circuit you have to get the flow correct or you potentially block the efficient operations of other circuits - in simplistic terms, say in the circuit before floatation, you need to match the flowput of the SAG that comes out with the input feed and output of the ball mill so you don't have 'blockages' in a very simple explanation (i.e. a bit more complex than that). Just to be clear ball milling is what gets you to p80 of 106 microns, so this stage is critical to subsequent floatation stage, and ball milling comes after the DMS stage. I wonder whether some of the issues of the other hard rock plays, especially PLS is because they have issues with the 'interaction' of the SAG and ball mill (or the ball milling itself for releasing the spodumene from the 'crushed' pegamatite itself prior to that stage, that comes in as say 3.35mm or 5.5 mm crush size, that is then ball milled down to say P80 of 106 microns) given the feedstock is also not homogeneous and a more volumeous ore input at that stage also occurs given lower recoveries at the DMS stage for these other plays - (noting PLS is also appearing to retrofit more capex at this stage so as to better improve the input feed for floatation, so that floatation actually achieves what it is intended to do).
The DFS for AVZ will be an interesting read, but ultimately for AVZ the issue is around transport costs, given the previous SS for a 2mtpa and 5 mtpa orfeed configuration indicated that 2/3rds of the opex costs were transport based. Minesite opex at minesite (noting it had floatation unit costs in those SS but no tantulum/tin credits) indicated for, say, a 5mtpa facility that at minesite opex was around US$102 per tonne (with transport costs then been US$221 per tonne). If transport costs come down through the latest Anns where AVZ is identifying new routes, and mine site costs stay ok, there is potntially a lot to get excited about here as I indicated in this post around IRR/NPV - Post #:
42594378
The last week has also seen a lot of props used in AVZ, and personally I am now not convinced (once bitten twice shy LOL) the buy order at 5.8c is genuine btw (given what happened with the previous big buy order at 6.6c that disappeared when about to be hit). The questions remains why these props?
All IMO
