Shoobridge exploration, page-7

This thread was titled Shoobridge, so I'll assume its more generically around NT ore. LPM commenced some met test work on 31 Oct 2023 with results expected Q3 2024. This will help provide a wider picture of NT ore's characteristics to build on results Core has from BP33/Grants and Grants actual results. Core has released met test information on 30 March 2017, 25 June 2018 (within the pre-feasibility study), 2 August 2018, 17 Apr 2019 (which became the source of 71.7% for the DFS) and 30 March 2020 (BP33).

The 50% recovery you mention is Q1 2024 aka Jul23-Sep23. Core was still arguably in the initial ramp-up phase at that point in time (although the volume ramp-up wasn't achieved). The recovery rates for Q3 2024 and Q4 2024 aka Jan-Mar24 and Apr-Jun24 were 60% and 63%. Results in the 60%'s is a normal range for existing DMS only operations, although some at times struggle to even get to that. Its typically only the scoping studies that are suggesting 70%+ DMS only recovery rates. For some unclear reason what's working in the lab isn't transferring to commercial scale real world situations.

The type of ore in Grants / BP33 is good stuff. Its high grade, larger spod crystal sizes with acceptable levels of iron. tick, tick, tick. Core's flow sheet hasn't even needed iron screening to keep iron at commercially acceptable levels.

Mining at Grants was generating more fines than expected and the exact reasons haven't been made public by Core. If these fines are primarily from crushing then the DMS is working pretty well but the 0.5mm fines screen before the DMS is working overtime. Less material than expected is entering the DMS which is pulling down recovery overall rates on mined volumes. Given the huge processing costs being reported in the AR, Core may have agreed a minimum fixed rate contract with Primero and not having got close to the point where variable rates kick in, Core was left with high processing unit costs.

Improving recoveries:
The easiest way to get a boost in recoveries is to drop the concentrate grade. Core's done this by reaching agreement with customers to ship 4.8% (60% Spodumene) rather than 5.2% or say 5.6% product (65% or 70% spodumene).

The second easiest way is to mine high-grade areas of the deposit. Core has few options in this regard and can't do what PLS did last quarter and mine areas that were 1.5% in grade when the deposit average was 1.15%.

With fines being generated by Crushing, Core's looked at the combined recovery across crushing and DMS operations and determined that a larger 10mm top size crush is optimal (6.3% was the original intended upper size). Its only due to the larger crystal size that moving up to 10mm is even an option. Core will have lower DMS recoveries but the gains made in less fines more than offset this loss.

Several knowledgeable commentators have noted that DMS works best for Spodumene when the material being processed is a similar size. A 0.5-2mm and 2-6.3mm DMS system will have a better recovery than one larger DMS running 0.5mm to 6.3mm. There may be recovery improvements with DMS reconfiguration to narrower size bands for each individual DMS/DMS pair and a narrower size range for each. For example PMT in their DFS only processing model propose 5 DMS units:

• A primary/secondary DMS for 4mm to 9.5mm
• A 1.5mm to 4.0m DMS
• A 0.65mm to 1.5mm DMS
• A 0.65mm to 3.3mm DMS handling recrush middlings from the primary/secondary 4 to 9.5mm DMS process.

Most of the recovery loss would appear to be in fines. Core's early test work of March 2017 explored a DMS+Flotation processing pathway and showed very strong flotation recovery rates. Core avoided flotation, presumably because of the additional complexity, capital cost and operating cost. Additionally the large WA mines were DMS. Since then multiple WA mines are going whole of ore flotation or adding flotation to their flow sheet. Core adding a back-end flotation unit could create a material lift in recovery rates with back-of-hand calculations indicating high 70% to low 80% may be possible. Core has noted this is being considered as part of the BP33 project.

There may be modifications to how the blasting / crushing is done that would reduce fines and therefore increase recoveries however I'd expect any simple adjustments would have been made in the first year of operation and trying to improve operational metrics.