Diffwys Quarry Floor 6 Longitudinal Mill

3D Model

Diffwys Slate Quarry (CN413, PRN20305), part of the Slate Landscape of Northwest Wales WHS, is located NE of Blaenau Ffestiniog. It opened in the 1760s and was the first formalised quarry in the town and the first to export slate to markets beyond North Wales. Production declined towards the end of the 19th century but small-scale extraction continued until 1925.

The ‘Floor 6’ longitudinal mill (PRN60258) is the largest building at the quarry. Now roofless, it retains all walls to full height. It is rectangular in shape, orientated E-W, approximately 92m long and up to 19m wide. The earliest part, from the 1850s or early 1860s, is at its centre. It was extended to the W and E in the later 19th century. Originally steam powered, it was one of the earliest ‘integrated’ mills and included all of the processes for producing finished roofing slates from raw blocks.

The mill was recorded on behalf of Cadw and Cyngor Gwynedd as part of condition monitoring works in 03/24.

Floor 6 models: https://skfb.ly/oSQoP