Two reason for the gold circuit. 1) They were losing gold hand...

Two reason for the gold circuit.
1) They were losing gold hand over fist from the UG, they only had three streams. (Two in reality Cu and Pb. The Zn was processed in the Pb circuit periodically). Hence the reason why they were able to re-treat tails.
2) The man who conceived the idea of the CIL, designed the CIL, approved the construction and built the CIL. Then left with all the money. It doesn't take too much research to see what was going on there.

On another note, forget about Sorby Hills, KBL do not have the money to get a FS off the ground let alone to start the CAPEX works for a project in that part of the Kimberley. The best thing they could do there is off load it for cash once and if the Pb prices go north. Besides they would need 10% Zn for it to be decent project.