If I change the recipe or mine the depot the droids die horrible deaths? So what's the method to scoop them up and move them to a new patch when they're finished with one?

Instead of asking, wasn't a better idea save the game and try it?
If something go wrong you can always reload the game to the last save, then you've nothing to lose to experiment yourself things...
BTW for recall drones back you can just remove them from depot and wait they come back from work.

They die painfully, but you don't lose any items :)

Thanks Klonan.

Foreros, the title at the top of the page is "Discussion". Look it up.

And, in a discussion, I've suggested you to try yourself, having the game a not-too-hard to use savegame function.
In the same answer I've suggested to you to remove drones from depot for recall them back from work and then move depot or readdress it to a new job.
Then I've satisfied any need of the discussion, both personal opinion and requested stuff. Nothing less, nothing more.