Building Suggestion: Mines?

[Psyren]

I was thinking, it would be interesting to be able to build a mining/gathering facility in a region.

What it does is after x amount of time, it adds 1 random common resource to your stock that area is able to generate? There are alternatives ideas to this like specialised mines (Metal Mines, Lumber Mines, etc.), but i prefer the totally random mine idea. So what do you think?

EDIT: Created a Mantis ticket here.