Gwynedd Archaeological
Trust Regional Historic Environment Record
Penrhyn Quarry, Landscape
Primary Reference Number (PRN) : 15840 Trust : Gwynedd Community : Llandygai Unitary authority : Gwynedd NGR : SH621653 Site Type (preferred type first) : MULTIPERIOD LANDSCAPE
Summary : The Penrhyn Slate Quarry is medieval in origin but owes its modern development to the marriage of Susannah Waburton, heiress of the moiety of the Penrhyn estate with Richard Pennant of Liverpool and Hanover Square, London (ennobled as Lord Penrhyn in 1793) in 1765. From the 1780s Pennant began vigorously to develop the estate, re-investing the profits from his Jamaican sugar plantations in agriculture, communications and, above all, in slate quarrying. These grew to be amongst the largest man-made excavations in the world, in which the slate was won from both from hillside galleries and from a deep pit. These came to be covered in the nineteenth century by an extensive tramway network, with counterbalance inclines lowering the raw blocks from the quarry face, and water-balance shafts raising them to the processing levels, where they were split into roofing slates by hand. Turbines and water-pressure engines pumped the quarry out.
A programme of modernisation from the 1960s swept away many features, though the substantial slate-rubble embankments of many of the railway and of the inclines survive. The functional buildings in the quarry are nearly all built of slate rubble and slate-roofed. They include a turbine-house, complete with turbine and compressor and generator, one of the mills built in the period 1907-1920 to produce roofing-slates as well as some more modern mill buildings, including one corrugated-iron second world war aircraft hangar. On the working levels are many small blast shelters, cabannau (mess-rooms) and weight-bridge houses from the nineteenth century.
Two distinctive surviving features are the head-frames from the water-balance shafts - a system for railing loads in which the tank underneath the two cages are filled at the top and emptied at the bottom of the shaft, their superior weight hauling up the empty tank, the cage to which it is attached and a loaded waggon. 'Sebastopol' shaft (SH 6202 6543) was inaugurated in 1858; its headrame was supplied by DeWinton's Union ironworks in Caernarfon. 'Princess May' shaft headframe (SH 6215 6537) was built in 1895 by Radcliffe's of Hawarden, a firm which supplied machinery to mining concerns all over the world. Devices such as these were introduced in the Lancashire coal-field in the eighteenth century, and were once very common in the shallower and self-draining pits of Glamorgan. They first appeared in the Gwynedd slate industry in 1829, but were only ever extensively used at Penrhyn, where five water-balance shafts continued in use until the 1960s.
Description : Penrhyn Quarry
Historic background: a major slate quarry, still in active production under Alfred McAlpine Slate products, once the largest slate quarry in the world. Its origins are almost certainly medieval, but it reaped the benefit of direct management and substantial investment from the 1760s onwards. It was served by a 2' gauge railway to the sea from 1801, realigned for locomotive operation between 1874 and 1879, and was equipped with a slab mill from c.1803.
A galleried slate quarry of great size, still in active production. Despite the scale of present quarrying operations, the quarry preserves the industrial landscape of the nineteenth century. Incline planes, galleries and ancillary structures survive as landscape features, and the quarry preserves a number of examples of quarry machinery from the 19th and 20th centuries. Operations are currently concentrated on the upper part of the quarry, and are likely to continue moving towards the south-west, but tipping continues to take place on the site of the 19th century workings.
Some attempt is being made to encourage tree-growth on the tips. The Felin Fawr workshops complex which formerly served the quarry at Coed y Parc survives largely intact.
Conservation priorities and management: preservation of the quarry landscape within the constraints of modern operation, including tips. Appropriate adaptation to areas not presently owned by Alfred McAlpine Slate Products such as Felin Fawr workshops area. (Gwyn and Thompson, 2000).
The quarrying landscape as a whole is being proposed for World Heritage Status and if accepted will be of international significance. (Kenney and Lowden, 2015)
© GAT)