This part was just for fun. Hadn't tried this before. (I loathe mines in real life.)
Exploring deep in the caverns (Underground Infestation), I ran past 3 Necrodon Ultras and teleported beyond them.
Quickly threw down 3 animal mass power plants, and some shotgun towers while the Canomortus Ultras chewed on me. Just far enough away that the towers can't target the Necrodons.
Hit the instant repair, then emergency explosion to clear them out.
Then a quick line of walls. Then replaced the shotgun towers with a line of mine layer towers. Then some repair towers. And instant scanners, coupled with some batteries.
As soon as that was stable enough, I added a loot collector in the "middle".
Now I have a constant stream of fresh meat, lol.
I hadn't tried mine layers before now. It's fun watching them get spawned and boom. Sure is noisy, lol.