Ty'n-y-bryn quarry (also known as Bwlch y Llan quarry or Lledr Vale quarry) was a

slate Slate is a fine-grained, foliated, homogeneous metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade regional metamorphism. It is the finest grained foliated metamorphic rock. ...

quarry that was worked from the 1840s to about 1914. It stands on the south-east edge of Dolwyddelan.

History

The original workings at Ty'n-y-bryn were started in the 1840s. In 1861, the quarry was restarted and a large mill was built just behind the Pentre-bont houses on the edge of Dolwyddelan. The mill had a large waterwheel which was fed from the Llyn Cwm-penamnen reservoir about to the south. In 1875, the Penllyn quarry was taken over by the company. Penllyn had been worked on a small scale since at least 1873, and was immediately to the east of Ty'n-y-bryn. The Ty'n-y-bryn mill processed slate from both quarries. In 1879, an incline was built down from the mill level to exchange sidings at

Dolwyddelan railway station Dolwyddelan railway station is a passenger station in the Lledr Valley, Wales, on the Conwy Valley Line from Llandudno Junction to Blaenau Ffestiniog, which is operated by Transport for Wales Rail. It is located at Pentre-Bont across the river ...

. Unusually, the incline was laid as

standard gauge A standard-gauge railway is a railway with a track gauge of . The standard gauge is also called Stephenson gauge (after George Stephenson), International gauge, UIC gauge, uniform gauge, normal gauge and European gauge in Europe, and SGR in Ea ...

, allowing wagons from the

London and North Western Railway The London and North Western Railway (LNWR, L&NWR) was a British railway company between 1846 and 1922. In the late 19th century, the L&NWR was the largest joint stock company in the United Kingdom. In 1923, it became a constituent of the Lo ...

to be taken up to the mill. It was one of only four slate quarries in North Wales that had standard gauge railway laid directly to its mill. Quarrying at the quarry ended in 1914. There was an attempt to restart Penllyn, again using the Ty'n-y-bryn mill, in 1920. This lasted until 1924, when all work ceased.

Geology

The quarry worked slate from the Nod Glas Formation, which outcrops along the

Lledr Valley The Lledr Valley () is a valley in Snowdonia in north Wales. It runs from the top of the Crimea Pass, north of Blaenau Ffestiniog down to Betws-y-Coed. The A470 road follows the line of the valley, as does the railway line from Blaenau Ffestin ...

. Through most of its length, the Nod Glas is black shale, but in the area around Dolwyddelan a

syncline In structural geology, a syncline is a fold with younger layers closer to the center of the structure, whereas an anticline is the inverse of a syncline. A synclinorium (plural synclinoriums or synclinoria) is a large syncline with superimpose ...

compressed the shales and it developed enough cleavage to be worked as slate.

References

{{Welsh Slate Quarries Slate mines in Conwy County Borough Railway inclines in Wales Dolwyddelan Former mines in Wales 1840s establishments in Wales 1924 disestablishments in Wales