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Cwt y Bugail Quarry (Bwlch-y-Slaters Quarry; New Manod Quarry), Blaenau Ffestiniog, Gwynedd, Wales, UK

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Latitude & Longitude (WGS84): 52° 59' 29'' North , 3° 53' 21'' West
Latitude & Longitude (decimal): 52.99149,-3.88933
UK National Grid Reference:SH732455
Köppen climate type:Cfb : Temperate oceanic climate
Other/historical region names associated with this locality:Merionethshire
Other regions containing this locality:Snowdonia National Park, Wales, UK

A predominately underground slate quarry/mine with a fascinating secret history.

NB This is not the (nearby) location more generally known to collectors as Manod Quarry and a location for blue anatase and other alpine-type minerals (see Manod Quarry (Manod New Setts)).

First worked in the mid 19th century, and known variously as Bwlch-y-Slaters Quarry or [New] Manod Quarry, it was acquired in 2001 by McAlpine, the world's largest slate company, and renamed Cwt y Bugail Quarry. Closed in September 2007, Cwt y Bugail Quarry supplied high quality blocks, slabs and paving but not roofing slate. The last rock worked here was granite used for the exterior facing on Mount Snowdon's new summit complex.

More recently, the quarry has become famous for being the secret repository where Britain's national art treasures were stored during the Second World War. Pictures from the royal palaces, from the Tate and the National Gallery, including 19 Rembrandts, Van Dykes, Leonardo da Vincis and Gainsboroughs, together with the Crown Jewels were brought to Manod's huge underground workings in vehicles disguised as delivery vehicles for a chocolate company.

Although again part worked for slate in the 1960s, the Government continued to lease part of the mine workings for 40 years until 1981, the heated ventilation system installed to protect the art treasures being maintained throughout this period. Although the masterpieces were removed when peace returned, the Department of the Environment was strangely unwilling to vacate the site. (Classified documents made pubic in 2002 have since revealed that in 1962, at the height of the Cuban missile crisis, secret plans were developed to move the nation's most important art treasures back to Manod to safeguard them from nuclear attack. The plan was abandoned because officials feared the potential impact on the public of hiding its art treasures might lead to chaos as people realised they should flee London). Finally in 1983, following a long court battle by a local quarry owner, the Government surrendered control of the caverns.

A further claim to fame is that part of the 1983 Dr Who series “The Five Doctors” was filmed at McAlpine’s Cwt y Bugail Quarry.

Mineral List

3 valid minerals.

Regional Geology

This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.

Click on geological units on the map for more information. Click here to view full-screen map on

456.5 - 470 Ma

ID: 2035401
Llanvirn Rocks (Undifferentiated)

Age: Ordovician (456.5 - 470 Ma)

Lithology: Mudstone, siltstone and sandstone

Reference: British Geological Survey. DiGMapGB-625. British Geological Survey ©NERC. [23]

Data and map coding provided by, used under Creative Commons Attribution 4.0 License

This page contains all mineral locality references listed on This does not claim to be a complete list. If you know of more minerals from this site, please register so you can add to our database. This locality information is for reference purposes only. You should never attempt to visit any sites listed in without first ensuring that you have the permission of the land and/or mineral rights holders for access and that you are aware of all safety precautions necessary.
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