The Pit of Problems
Here you go! Here's a free map I threw together for a game the other night, you're more than welcome to use it for your games.
The Abandoned Mines of Mount Explodey
And another one!
This was what I'd imagined was once a dwarf mine that dug up magically charged minerals from near a fissure to the Elemental Plane Of Fire, but something went wrong and the mine went on fire - now the upper levels are haunted by the burning ghosts of the miners. Or a dragon moved in and drove them out. Or it's still a working mine and the dwarf inhabitants are assholes now. You decide.