Ynys-y-Pandy-slate-mill, Cwmystradllyn

Site Description The impressive three-storeyed Ynys-y-pandy slate processing works, which served the Gorseddau Quarry, was built in 1856-7 by Evan Jones of Garndolbenmaen and probably designed by James Brunlees. It is ingeniously planned so that the natural fall of the site assisted the manufacturing process. A deep trench inside accommodated a large overshot water wheel (26 ft, 8m in diameter), and on the south side a long curving ramp brought branches of the tramway from Gorseddau Quarry into the mill at two different levels, serving the middle and upper floors. The grand, round-headed openings are closely spaced like a Roman aqueduct. The eastern gable is surmounted by a decorative feature incorporating a false shimney stack, and the west gable windows have at some time had window frames or shutters. Otherwise the construction is bold and plain but none the less impressive.