Ann: Commencing Preliminary Discussions, page-33

Think you are spot on here Geo and this explains the different share price directions and qanta. CNB sp would be negatively affected as HMX is massive dilution for little immediate benefit. Yes they'd get increased tonnage and access but given the dire cash position of HMX and their inability to hit pay dirt or even stay on target .... why bother. Just wait until they implode and cherry pick the pieces.
HMX on the other hand is desperate for both cash and results so the talks represent a real benefit, plus has the ability to revise current management which has not only failed to deliver but actively driven sp down. This is why it's boosting HMX.
Personally, I think it will end in a cash for access/partial tenement which will work for HMX as it keeps them alive and in lucrative employment, and CNB as it develops their asset.