Dorothea Quarry

Coordinates: 53°03′15″N 4°14′36″W / 53.054194°N 4.243437°W

Dorothea Quarry
Dorothea Quarry
Dorothea Quarry Dorothea Quarry shown within Wales
OS grid reference	SH5177350251
List of places UK Wales

Dorothea Quarry is a large slate quarry in the Nantlle Valley in North Wales.

History

Dorothea Quarry commenced working in the early 1820s, though there were a number of smaller workings on or near the site before this. By 1848 it had become the dominant quarry in the area, employing 200 men and producing 5000 tons of finished slate. Production peaked in 1872 at 17442 tons. In the 1930s over 350 men were employed at Dorothea. Production dropped significantly after the start of World War II and the quarry closed in 1970.^[1]

Since quarrying ended in 1970, the Dorothea Quarry has flooded and become a popular site for scuba diving (even though there are no facilities provided, and diving is officially banned in the quarry); the unregulated nature and depth of the site has encouraged some divers to overestimate their capabilities – in the decade 1994-2004 21 divers lost their lives in the quarry.^[2]

Description

The quarry sits at the bottom of the wide Nantlle valley and consists of six pits, the deepest dropping 106m from the surface. The slate veins here run vertically, allowing unusually deep vertical pits to be dug. Because the pits fall below the water table they needed to be constantly pumped to stay dry. A Cornish Beam Engine was installed in 1904 to pump the pits; it stayed in use until 1951 when it was replaced with electric pumps.^[1]

Transportation

The quarry was one of the first users of the 3 ft 6 in (1,067 mm) Nantlle Railway in 1828. It later developed an extensive internal tramway system of 2 ft (610 mm) gauge. Dorothea was one of the first users of De Winton locomotives in 1869.^[1]

Locomotives

2 ft (610 mm) gauge locomotives known to have worked at Dorothea.

Name	Builder	Works No.	Date built	Type	Notes
Dorothea	Hunslet	763	1901	0-4-0ST	Worked until 1942. Now preserved on the Launceston Steam Railway[3]
Wendy	W.G. Bagnall	2091	1919	0-4-0ST	Purchased from the Votty & Bowydd Quarry in Blaenau Ffestiniog in 1930. Preserved by the Hampshire Narrow Gauge Railway Trust[4]

References

1. Richards, Alun John. The Slate Regions of North and Mid Wales. pp. 70–71.
2. "Why Dorothea claims lives". North-west Wales News. BBC Online. 2004-03-22. Retrieved 2007-03-16.
3. "Dorothea". Launceston Steam Railway.
4. "Dorothea Slate Quarry". The Narrow Gauge Railway Museum.