From memory, E1 North had a heap of fluorine and some uranium...

From memory, E1 North had a heap of fluorine and some uranium (but never enough to be an issue). Monakoff had heaps of oxidized Zn that suppressed copper flotation to the point where the first loads or ore through the plant resulted in shitty Zn cons with minor Cu. E1 South didn't have as much fluorine as E1 North, but did have elevated Zn and Pb like Monakoff. Not enough to be economically recoverable, but enough to require a processing strategy.
The main reason for mothballing E1S and East was the economics of the copper resource though, not just the met. Monakoff's problems were metallurgical and compounded by the fact that the deposit is small so the fixed costs in to developing a a process to treat the ore really ate into the margins.