Will this add a Paydirt filltype to any map?
Viewing post in Mining + PiT Layers — FS25 TerraFarm add-on comments
No — Mining Layers doesn't add or register any fill types. It only uses what the base game, your map and your other mods already provide. Paydirt itself isn't a base-game fill type in FS25: mining maps and mining mods bring it, which is why it's often there anyway. If your map doesn't have it, pick a different seam material in the layer editor (COAL, LIMESTONE, STONE, GRAVEL, SAND — anything your map knows works; the log lists them all at startup). Good question, it's in the FAQ now.