Gyfrinachol Mine is a Coal mine with evidence of mining in the 19thC through to mid 20thC. It descends through a drift down several levels with the earlier methods of mining visable closest to the entry way, working on down to clear 1920's-1950s workings. The lower workings, just below what I believe to be the stables, are totally flooded, a situation exasabated by a water course that interjects into the mine.
Footprints are throughout, downed tools at areas of fatality, and of course bottles and candles throughout.
Interestingly enough, close to surface level there appears to be a training area for seam working.
Reasearch has shown fatalaties in this mine were quite high throughout its operation, prior to the knowledge of this, there are emotional hotspots in the mine, and a video was recorded with a "Third Voice" on it (Only 2 people in the mine).
Delamination is throughout, and several people died through falls during its working operation.
It is a self venting mine, and air quality throughout is comparable with that of the surface.
These workings are now totally sealed, and there is no access possible.