From my understanding, C1 cash costs (which KZL report) are calculated based on an industry wide agreed standard.
The C1 cash cost is determined on the major resource (for instance, in this case - Zinc). Any by-products mined (in this case - copper) are sold and the revenue obtained from the by-products are used to reduce the C1 cash cost for the major resource. Mines that have large by-products, can therefore have neg C1 cash costs.
So, yes, you are correct, the 6000t of copper byproduct from the Zinc mine is written off the C1 Zinc cash cost and the copper number is 1,4000t as you have indicated, not 20,000t.
BB and Gself, I am happy to be corrected here.
HT1
KZL Price at posting:
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