Headwater Bonus Objective

[TheKing]

So I'm trying to go for a completionist run and it turns out there is a Bonus objective in the Human campaign which apparently can't be completed. In the Player Profil screen there is a bonus objective for the Headwater mission stating "Build any Econ Tech in the Silo" the thing is during the headwater mission that Bonus objective is never shown and all Econ Tech options in the silo appear to be locked. The objective also doesn't show up in the mission complete screen yet its there in the Player profile and googeling around shows this objective listed in various guides. Can someone give me a pointer what's going on?

[Hevi]

Sorry for necro but i finally managed to get this. You just need to build second refinery and place second extractor far away from the base (lower right part of the map). Lucy will then say something about harvesters being vulnerable and unlocks one of the techs in the silo.

[TheKing]

Thanks, perhaps it'll be useful for another player :)

[X-C-V]

Still very helpful, this one finally helped me to get the final bonus mission I missed, thanks