MC1.10.2
Railcraft v10.0.0

I set all the poor ore to not generate via the configs.
I generated a fresh world in creative and used the RFTools builder to clear out a few chunks leaving only ore behind. I found plenty or poor copper ore even though the config was set to false upon world generation.

JK. Somehow I got some old save file that I deleted when I thought I was generating a new world.