Llywernog Silver-Lead Mine Museum (Ponterwyd, not far from Aberystwyth) - In the 1740's, this water-powered mine was worked for silver and lead, and continued until the 1880's. This open air museum has mining machinery, operating water wheels and tour of the tunnels (put on your hard hat and lamp).

Dolaucothi Gold Mines (Pumpsaint, near Lampeter) - The Romans knew a good thing when they saw it, and it was gold in seams where it could be easily mined (of course, it took Roman slaves to do it). Tour these mines where you can see remnants of the old Roman works, including their aqueduct system, the underground tunnels, and working mining equipment.