These tunnels lie just north of Llechwedd, does anyone know their history? Possibly the stream has just been diverted away from the Llechwedd workings, but then why is there more than one route through? A few scrappy chambers have been developed but the main focus appears to have been channelling the stream. Was it being moved to provide a source of power?

As far as i know they were dug to divert the river/stream away from the workings. They were effective by keeping the mine a little drier.
I was told that they have been surveyed by the folks at Plas Tan y Bwlch (?)

Briefly:
To reduce the work of pumping, and to prevent the possibility of the Afon Barlwyd overflowing its bed into the open workings (and presumably to allow the open workings to be “untopped” further to the north), a diversion tunnel was driven by contractors (?Treglowan) under Cribau, the hillside to the north of Llechwedd itself and sluice put in the river to divert it through the new course. The construction of this diversion began in 1895 and the initial tunnel, now referred to as the “Lower Cribau” was completed by 1901. Unfortunately this appears to have been too close to the quarry, and also had problems “catching” the water from the stream. It was replaced by a second “Upper Cribau” tunnel which took its water from much higher up the Barlwyd by 1905. This was connected to the lower tunnel near its exit point by an inclined shaft. This also ran into problems and the tunnel was continued on the same heading as far as Tai’r Frest, the extension becoming known as the “Tai’r Frest Level” – this was connected by an inclined shaft to a new lower tunnel “Goodman’s Level” which connected directly into the Lower Cribau again near the exit. Goodman’s were the tunnelling contractors who carried out the sheme. The older branch was dammed off. This appears to have been successful. It is this diversion which produces the high cascade just between Plas Waenydd and Quarry Tours today.


Outline map to follow.


Grahami

---

OK - here's the map.

🔗Personal-Album-54-Image-084[linkphoto]Personal-Album-54-Image-084[/linkphoto][/link]

Grahami

---

What sort of size (ie cross section) are these tunnels?

---

I have walked up thrugh the one wearing wellies. The water was running down even after a spell of dry weather. You come out in a culvert higher up the mountain.
Height was approx 5 to 6 ft. And about 5ft wide.

---

About the same as a normal adit.

Chris.

Should have said in my original post that the info. I posted was condensed from some originally given to me by Harold Morris of Porthmadog, there is, of course, other info to be found in the Greaves papers at Dolgellau Archives.

Grahami

---