Penarth Slate Mine closed in the 1930's, Located in the Llangollen area near Carrog on the top of a hill, recommended as an intro to mines with bits to see in the mine and also outside of the mine. Quite a few chambers & levels to explore with carts, tracks and Cabans remaining.
However there is gas in the furthest reaches of the east vein, care should be taken if visiting.
A Few outside first:
http://i408.photobucket.com/albums/pp161/ogof1/IMG.jpg
http://i408.photobucket.com/albums/p...1/IMG_1719.jpg
http://i408.photobucket.com/albums/p...1/IMG_1727.jpg
Air Tank (I thank)
http://i408.photobucket.com/albums/p...1/IMG_1728.jpg
Now the inside:
Incline
http://i408.photobucket.com/albums/p...1/IMG_1696.jpg
Track
http://i408.photobucket.com/albums/p...1/IMG_1697.jpg
Tunnel
http://i408.photobucket.com/albums/p...1/IMG_1689.jpg
Caban
http://i408.photobucket.com/albums/p...1/IMG_1661.jpg
Box
http://i408.photobucket.com/albums/p...1/IMG_1663.jpg
Cart
http://i408.photobucket.com/albums/p...1/IMG_1690.jpg
http://i408.photobucket.com/albums/p...1/IMG_1706.jpg
http://i408.photobucket.com/albums/p...1/IMG_1636.jpg
http://i408.photobucket.com/albums/p...1/IMG_1637.jpg
Shovel
http://i408.photobucket.com/albums/p...1/IMG_1622.jpg
http://i408.photobucket.com/albums/p...1/IMG_1665.jpg