Report by Jules Barrett
Cavers: Jules Barrett (EPC), Bob Toogood (EPC), Dave Gledhill (EPC)

I'd heard about the work that the Friends of Cwmorthin had been doing in Cwmorthin Mine and fancied having a look for myself. Since we were in the area having done the Croesor-Rhosydd Through Trip a visit to Cwmorthin Mine was the obvious choice for a Sunday trip. Darkplaces and Miles from 'Friends of Cwmorthin' had kindly supplied me with the code for the gate so we could get in. In the '60s the Eldon Pothole Club used to have a club hut on the shore of Llyn Cwmorthin so would be interesting to see that too. Bob Toogood used to visit the hut to climb and explore the mines so was nice to visit the place with him. After the customary breakfast at Jenny's in Porthmadog we drove to Blaenau Ffestiniog and then onto the car park above the village of Tanygrisiau. We got changed into dry caving kit here and walked up the track which leads to Llyn Cwmorthin. Soon, the old club hut came into view. It appears to be abandoned these days with windows boarded up and no sign of life. The Lake Level Adit entrance to Cwmorthin was easy to find in a significant cutting quite close to the buildings. Near the entrance a large, rusty steel cable lies snapped on the ground. Apparently in the '60s one end of this cable was anchored well above the adit entrance and fast descents hanging on to a U-bolt with sparks flying were common. Two blokes at the bottom stopped you with a dynamic belay before you hit the ground! We opened the substantial gate and walked along the adit into the mine. First of all we headed down an incline ('Back Vein North Sink Incline') to where a couple of trucks have crashed. From here we explored down the incline a little way, then came back and had a look at the large chambers near to the entrance. Cwmorthin is a great mine with loads to see and these first chambers have an impressive staircase made of stone and timber which the miners used to access the workings. After a good look around here we headed back to the Lake Level Adit and continued further into the mine. There is a little round trip that you can do and we thought we'd try to find our way around that. Route-finding was easy enough with the help of a description that we found on and the first place we visited was the area around the 'Old Vein South Sink'. Here some substantial timbers are wedged across the passage and between the floor and the roof and the area has a slightly loose feel to it. Continued on through a short crawl and past largish chambers to descend some nice stone stairs and then past an old dam. Before long we were climbing down an aluminium ladder and on down to the site of 'Compressor 1935'. From here we made our way to 'Lefel Ffrench' and into a level containing knee deep water. Splashed along this a little way to reach the bottom of the 'Back Vein North Sink Incline'. On the way out we took a detour to cross a well-preserved bridge and exited as the miners would have exited up the old stairs to the Lake Level Adit. We had an excellent trip but there is obviously a lot more to see in Cwmorthin Mine. Cwmorthin connects with Oakley Mine and I've heard rumours of a through trip which would be nice to do.

Cwmorthin is a lovely place with superb scenery both above and below ground. The Friends of Cwmorthin have done excellent work keeping the entrance open and deserve the thanks and support of everyone interested in underground exploration. More information available from:

The route that we followed is available on the internet at:

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