why, page-3

If MEL sell their share of Gum Flat, then they will obviously no longer be contributing to the project funding so LML will need to find the funds from somewhere else.

However the announcement clearly says this is only one option. The other is that an interested third party could pick up the slack and take over MEL's 40% share. This would possibly include an agreement similar to the one that exists with MEL, i.e. continual funding for Gum Flat exploration (this would make sense, since it would be in their own interest to progress things).