AW1 General Chat, page-2567

The X-Ray sensor will easily differentiate the copper-zinc sulphide particles (SG = 4.1 - 5.7 g/cm3) from the dolomite gangue particles (S.G = 2.9 g/cm3) found at Storm due to differences in the particle density.

Given malachite is a copper carbonate hydroxide mineral (SG = 3.8 g/cm3), its density is still higher than dolomite (SG = 2.9 g/cm3) so should be able to be sensed by the X-Ray detector. Alternatively, an Optical / Near-Infared (NIR) sensor could be utilised to exploit differences in colour between green and grey (or non-green) coloured particles.

The iron sulphides (pyrite & pyrrhotite) will be hard to separate from the Cu-Zn sulphide particles due to overlapping densities, hence slightly diluting the final concentrate grade of the DSO. This is not a concern for a copper smelter buying the DSO material because a flotation plant would normally include all these sulphides in its finely ground (<200 micron) bulk concentrate product. The copper and zinc metal would ultimately be produced after smelting and electrolytic refining steps.



Reference: Average density - colour - chemical formula of Storm Minerals