Steel

[Moristans]

We'll also need someone who can mine iron and coal. I assume we'll be fine for a while with all the scrap metal sitting around this world, but eventually we'll need to mine for more.

Who wants to learn about mining iron and coal?!

If you're seriously worried about mining your own coal and iron ore, you're talking about rebuilding civilization from scratch. There is enough raw material in scrap metal and junk to fashion anything you might be able to need or make for the population numbers that you are going to be supporting for generations to come.

I'd concentrate more on recycling and mould-making than worrying about smelting your own raw materials.

You'll also need to worry about reliable and sustainable source of fuel for your "industry" before you worry about building one from the ground up.