Cu and - Zn is the appeal -- for suitors Zn is a 'steady hand' commodity but - supply is becoming a world wide problem - Yur right - by itself depending on Zn by itself could lead to questionable/volatile mine economics - BUT - NSU has a combination of 2 very good metal reserves.
Go back to the RMC situation! Lundin bid on RMC because it wanted to become a major Cu AND Zn producer. NSU now fills this bill even more nicely than RMC!.
My view is that Lundin, now with a pot of cash from a sale, will take a run at NSU - before Cu and Zn prices get much higher -- it has great Cu AND Zn potential to support a strong bid and it fits their strategic objectives nicely. It is likely other majors are sniffing around as well - this is an unusually good opportunity at the right/current metal prices.
then again - who knows .