Craig Cwm-trwsgl behind the old slab mill of the Prince of Wales Slate Quarry, which was mainly worked between 1873 & 1886.
The mill was built at the new terminus of the Gorseddau Tramway.
The mill dealt only with slab, reduction of roofing slate taking place on the terraces.
At its peak the quarry employed 200 men producing 5000 tons per annum.
The quarry closed in 1886 but some small-scale working continued until 1920.
The Slab Mill was an experimental, water-powered facility built in 1864 to saw slate slabs, and later developed more fully around 1873.
The saws were powered by a water wheel, located in a water-pit, immediately right of the building,
using water brought in by a pipe, supported by launder pillars, from the nearby river which was fed by the reservoir.
Ref: NW 4843
Date: 28/09/2025
Location: SH 5445 4930
