The short answer is E25's scoping study for HPMSM noted a 30-33% Mn feed grade to the Louisiana. While inefficient, Butcherbird's current processes while can deliver product in the grade range assumption needed although its at the bottom of the range. The planned mine upgrade involving DMS will more efficiently deliver product in this range.
This however somewhat misses the point about what HPMSM is.
MnSO4.H2O is the chemical formula for HPMSM.- Mn has an atomic weight of 54.938044
- SO4 has an atomic weight of 96.0676
- H2O has an atomic weight of 18.01528
- The total atomic weight is 169.0209 and the Mn element of that is 32.504%
So the HPMSM conversion process is about removing basically 100% of everything that isn't Mn and substituting that non-Mn material with SO2 and water (H2O). After this, you have Manganese Sulphate Monohydrate. If the process has been successful at removing everything else its high purity. If you had a MSM product grade that was 31% Mn or 34% Mn its low purity because the impurities have taken the product away from the theoretical value of 32.50%.
If for example iron starts at 10% and you want 99.99% purity then Iron needs to be reduced below 0.01% (well everything needs to cumulatively be only 0.01%). From the ore that comes out of the ground, its all about getting the Si, Fe and Al percentages down to zero.
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