When you choose map, hold down shift, then write pippin. choose the red land. Now you should be able to mine lots of resources from the hills and mountains.

To learn what the key word is for a world you are playing in, and presumably like, control-click on the magnifying glass on the terrain map screen. In multiplayer mode, this will also show the name of the multiplayer game. To re-generate the same world from scratch, control-click on the globe on the random world generation screen. On the pop-up that appears, type in the key word.