RE: Revenue v profit10 May 2026 22:39
Re. blending,
So with first year of pre stripping waste and targeted ore extraction of 430,000 tonnes, primary crushing of ore with 25% going as fine crush straight to the plant, why does it upgrade to 2.76%Cu?
This phenomenon due to “preferential breakage of friable chalcocite” is typical where softer, valuable minerals break down more easily than others concentrating in finer size fractions and increasing the grade in those fractions relative to the original ore. The ore contains various copper minerals, with chalcocite, a common copper sulfide mineral.
After crushing, if 25% of the ore reverts to a grade of 2.76% copper, then the remaining 75% of the ore will have its contained copper grade reduced to approximately 0.48%copper.
This is because of the redistribution of copper, where the finer fraction becomes enriched, and the coarser fraction still retained is reduced accordingly.
So that leaves 323,250 tonnes of ore now at a contained copper grade of 0.48% that goes through the ore sorter that reduces the mass by 55% but loses 15% of the contained copper, the resulting contained copper grade will be upgraded back up to approximately 0.91% cu just shy of the virgin grade, against the fines at 2.78% cu
Hence the grade imbalance delivered to NLZM