Ore patches now spill over into the sea as submerged variants. Dredge them up with new floating hardware, and build deeper into the blue with water-placeable refined concrete.
I see the description that landfill doesn't bring ore to the surface and that's cool. However, what I was expecting was when I deleted the landfill, that the ores would reappear. They don't! They're just deleted. Can you have them be hidden or something and uncovered when the landfill is removed?
This would need some fairly sophisticated scripting if it's even possible at all; if someone made a pull request for it and it worked well, I'd accept it, but I don't have the wherewithal to design it myself.