I have no doubt management have tried this. Nothing to do with FIRB. Its not like Zijin are offering is $1-$2 and we are saying no.
Yeah I can't see why Zijin would contemplate shelling out literal billions for something that they have a reasonable chance of getting anyway for nearly nada. The north at least is well in their grasp, and thats what they are planning to build a mine on.
The only way I can see a viable offer coming from Zijin is further down the line, should it become apparent that the ICSID ruling is likely to bring them significant trouble, namely in terms calling 'their' tenement area and licence into question. Then we could plausibly see a buy-out attempt, just to secure the minerals beyond all doubt, though that would still be unlikely IMO to reach the levels any of us would deem warranted.
In the meantime I'd say they are content to let the questions over the 'south' continue to drag on, whilst they progress with mine development. Hard to argue with their prospect as a potential partner when one tenement lies dormant whilst another nears production. Even though that is 110% down to shitfuckery, it'll still make it easier for our corrupt enemies in DRC to press their case