← Dive-sites: Cwmorthin Mine ⚠
Description
Cwmorthin is an extensive and large mine next to Blaenau Ffestiniog. It’s main entrance is not far from the shore of Llyn Cwmorthin, a lake formed near the spill of the mine.
The mine itself is used by many of the adventure companies in the local area and the keys are available for free to experienced people. Much of the deeper sections are flooded but some of those that aren’t are equipped with pitches, zip-lines and traverses.
I’ve no idea if any of the mine has been dived but it appears there are certainly sections which would be suitable to those who are trained to do so.
Much more information is available at The Friends of Cwmorthin Slate Quarry and AditNow Mine Exploration & Mining History website.
Images

Key Metrics
Region | Personnel Access | Road Access | Depth (m) * | Permission needed | Lat Long (DD) | Elevation (m) |
---|---|---|---|---|---|---|
Gwynedd (C) | -/5 Unknown | -/5 Unknown | By Appointment | 52.997641,-3.969211 | 323 |
Site Maps

Directions
(Click the ‘Lat/Long’ data in the ‘Key Metrics’ section for Google Maps directions)
Additional Risks
- Coming Soon if Applicable
References
- ©OpenStreetMap contributors