The Cae Coch Sulphur Mine lies on Forestry Commission land in the Gwydyr Forest, north Wales and is one of the weirdest places I have ever been.      Much of the mine is on a steep, gravelly slope with orange and red pools of sulphur, bacteria feed on the chemicals and minerals in the mine adding to it’s rainbow of colours.  ‘Snotites’ dangle from the roof, several feet long and looking like stalactites – except that they  they wriggle and dance if you blow on them.  They are not solid structures made from calcite as in cave formations, but are organic bacterial and have been caused by water dripping from the roof containing the bacteria.  They are just like long dripping snot!

As the miners had worked the pyrites bed containing both sulphur and iron, they had left pillars approximately two to three meters in diameter, at irregular intervals of about ten meters apart to support the roof.   Where the roof is less stable thick wooden supports were jammed between roof and floor, but these are rotting  and roof collapse in the mine is common.

There are records of mining in the Cae Coch Sulphur Mine dating back to the end of the eighteenth century but it is believed that Cae Coch mine has been a source of sulphur as far back as the Roman occupation.   The mine closed in May 1942 and has been left to decay ever since.

Cavers preparing to enter Cae Coch Sulphur Mine

The mine entrance

Rotten wooden supports keeping the roof up