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Cof Cymru: National Historic Assets of Wales · Wales

Quarry Office

Llandygai, Gwynedd, Wales

The record

Designation
Listed building, Grade II
Broad class
Industrial
Date of designation
24 May 2000
Locality
Penrhyn Slate Quarry
Town
Bangor
Community
Llandygai
Unitary authority
Gwynedd
Country
Wales
Coordinates
53.16759, -4.06558
Cadw reference
23392

Slide toward Today to fade the historical sheet and see the modern map underneath.

David Rumsey Map Collection, Stanford Libraries

Shown on 5 historical map sheets, the earliest the 1896 "Sheet 7. Ordnance Survey of England and Wales." (David Rumsey Map Collection, Stanford Libraries).

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This record in Cadw's own full report ↗

Cadw's description

Located at centre of quarry on 'Red Lion' Level with majority of working buildings to north.

Penrhyn Quarry makes up the largest slate workings in the world, and has remained in continuous production since long before the capitalisation of the workings by the first Lord Penrhyn in the late C18. An iron railway connected the quarry to the sea at Porth Penrhyn by 1801 and a mill for the production of slate slabs at Coed-y-parc to the north of the quarry was open by 1803. The quarry was worked partly as a stepped gallery and partly as a pit, which required uphaulage equipment, although from c1850 it began to employ water-balance shafts to raise loaded wagons, a type of technology already common in coal mines. Production of roofing slates remained entirely unmechanised in gwaliau until the introduction of electricity in 1912 led to the building of a range of mills on 'Red Lion', the main quarry level, and the installation of blondin ropeways in the upper quarry. In 1964 the site was bought by McAlpine's which has led to extensive modernisation. The quarry office was built c1860 during a period of expansion at the quarry and in recent years has been considerably extended.

Single-storey building in a simpler version of the free Italianate style used for the Penrhyn Estate office at Porth Penrhyn. Regularly coursed and dressed rubblestone blocks with finely jointed voussoirs to door and window surrounds; mainly hipped slate roof. Main elevation has projecting stepped gable to left with round-arched recess framing tripartite sash window with glazing bars and 4-paned sash window above; entrance to right return through segmental-headed 4-panel door. Main section to right has 2 segmental-headed sash windows with similar 2-paned sash window to right again in front wall of small hip-roofed square projection. 2 similar 6-paned sashes in segmental-headed surrounds to right return of main section and 3 sash windows to back wall, all to left of lean-to porch in angle with rear projection giving access to large C20 extension linked to original building. Slate slab ridge stack to far right of main range and similar stacks towards top of its hipped ends.

Interior retains slate fireplaces with bracketed surrounds.

Included, notwithstanding considerable late C20 extension, as the Victorian quarry office of this nationally important slate quarry; group value with adjoining 'Sebastopol' water-balance shaft.

Nearby in the register

Other entries of the same register within about three miles of this one, by straight line.

Designated Historic Asset GIS Data, The Welsh Historic Environment Service (Cadw), 2026-09-07, licensed under the Open Government Licence http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/ Cadw, the Welsh Historic Environment Service · Open Government Licence v3.0
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