Some thoughts on recoveriesOne of the interesting quirks of the...

Some thoughts on recoveries
One of the interesting quirks of the lithium space is that Met test results come out at a time in projects life when companies are trying to appeal to a wider investor base to raise money to fully develop projects. This has led to the accepted norm of releasing "HLS test results" rather than overall recovery results as this enables the release of a number perhaps 10-15% higher. Because the work is done in stages the existence of the word "Global" in the title doesn't guarantee that the results are inclusive of fines results. Indeed I'd if the tables say HLS test results and there is no quantification of the impact of fines I'd suggest the results released are very likely HLS only. Many posters either intentionally or inadvertently the repeat these HLS test results as overall recovery results creating comments like referencing superior Canadian spodumene resources as to why projects there reference higher recovery rates.

A couple of BP33 announcements from 2020 show this issue well. On 10 March 2020 Core released the table below. The HLS recovery rate using a 2mm-10mm size fraction was 84.7% to a 5.74% grade. The HLS recovery rate using 0.85mm to 2.0mm was 84.6% to a grade of 5.38%. From the material presented to HLS for test work there was an excellent recovery rate. The problem appears to be that as the ore was crushed, a lot of fines occurred - far more than expected. All projects will have crushed fines, the only question is how much. For BP33 it was modelled at 19.8% (by weight) and 14.4% by lithia content. The overall recovery equation became 14.4% * 0% recovery + 85.6% * 84.65% recovery = 72.5%.

When Core announced horrible recovery rates for Grants (Grants and BP33 ore are similar), Core noted fines of 35-40% at Grants. Using the simplistic option of doubling the 19.8% and 14.4% there may have been 28.8% lithia lost as fines. The theoretical recovery equation become: 28.8% * 0% + 71.2% * 84.7% = 60.3%. Even if the DMS is working particularly well, high fines kill the recovery rate. If the DMS was at that stage at 70% recovery rates, overall recoveries would have been 50%. Core has done work to improve DMS recovery rates and reduce fines. the blend is now 63% recovery rates.



Soon after this on 15 April Core released some test work using a 6.3mm crush size. Fines increased from 19.8% to 21.0%. On this 6.0% test work the overall recovery was 70.6% but it was about 84% recovery rates on the HLS test work and 0% recovery rates on the 16% of material that was fines. Its another example of where fines have been clearly laid out (they haven't in all Core's reporting and frequently aren't in other companies).


Implications
Unless a solution is found that lowers crushing fines, DMS (or even an enhanced DMS) will struggle to get 70%ish recoveries. One solution is flotation but there may be others as LRS were proposing a 3% product and talking about sand processing (<0.5mm) in their met test work.

When reading other announcements noting high 70% or 80% HLS test results, have a think about whether or not this result includes fines. I'm pretty sure the 79% recovery rate Patriot announced on 22 Feb 2023 was HLS test results only with the work closely mirroring the size range used by Core (0.85mm to 9.5mm). I suspect the WR1 met test results on a 0.85mm to 6.3mm screen size are from the HLS test work only although some confusing terminology is used. Others like LRS has were reporting results into the mid 80%'s but this dropped to low 70% inclusive of fines. LRS then included plans to recover from sub 0.5% material that boosted the modelled recovery back to high 70%'s.

The ore from BP33 is high grade. Its high quality (Those iron readings are excellent). It has great recovery rates through the DMS. The problem is that Grants and presumably BP33 ore breaks into little pieces easily that don't get into the DMS to be recovered.