72.6% recovery at 6.0% is a commercial grade that works and is IMO a fantastic result from 1.1% head-grade material.
As context, Core's DFS had an average 1.3% grade with a lower 71.7% recovery and was "only" producing 5.8% Spod. Core used a 0.5mm to 10mm crush so some of the middlings that weren't processed by GT1 were necessary to get Core's recovery.
The recovery going through the HLS process has been confirmed at over 90%. (72.6 / (100-20.9)) = 91.8%. While the 8mm crush work has an overall 72.6% recovery, there would appear significant upside from a fines back-end floatation circuit. 20.9% of the lithia was lost as fines and middlings. If a back-end floatation circuit was processing this material and achieved even a 50% recovery, this would add another 10.4% to the overall recovery taking it up to 83%. The only negative I'd see from this is ideally the % Fe
2O
3 would be below 1%. Whether this level is a problem will become apparent in the Hydroxide test work.
The 99t bulk sample will see if part of the reason for high fines/middlings is due to using drill core. By definition the DD core is a circular cut through anything that gets in the way. This will mean that any spod crystals on the edge where the cut is made will be sliced, rather than have the chance to be broken apart. I suspect most, if not all the core used will have also been sliced in half for processing of lithium assay's. What was 4.2cm wide became a 2.1cm thick semi-circle. At an 8mm crush you will be getting a lot of fines and middlings due to all these drill slices through the core. The process therefore biases the recovery rates downwards. I'd expect to see the fines/middlings percentage drop as testing shifts to bulk samples. If this material isn't in fines/middlings then it's going through HLS for potentially 90%+ recovery rates and the overall recovery rate is increasing beyond 72.6%.
As context, this slide was part of the FFX presentation pack of 7 April 2022. Even on this early test work the above in-production mines. A number of the 80%+ projects are partial or full floatation circuits.
