I installed your mod on a pure Minecraft 1.16.5. Where do I get copper? - It will be added to Minecraft 1.17.

It should generate in the overworld, maybe have a look around in spectator mode?

It should generate in the overworld, maybe have a look around in spectator mode?

Does this mod generate copper itself? (if there is no plugin that provides copper)

Yes it does generate copper. You can see what ores are generated by looking at the config in config/modern_industrialization.toml.

My mistake. I added the mod after generating the world, it was necessary to go very far from the starting location to find copper.