What happens when a mining corp runs out of its resource?

Since it is not possible to change what a mining corp produces, what happens when it runs out of its natural resource?

It closes.

They have a very long profitable period. Then they indeed close.

What Andy said is correct, and was better phrased than what I said. I absolutely build mining corps whenever I can. While they still have available resources, they're generally the most profitable corps you can build.

There is a discovery process running now.
there will be new natural resources in all countries soon.