Part of NPRN 40590. The slate and slab mill sits on the valley floor at the foot of the steep slope under which lie the workings (NPRN 408348). It consists of a large building, now lacking its roof, 46 metres long and 11 metres wide internally. At its north-east end was a waterwheel 30ft (9.1 metres) in diameter and 4ft (1.2 metres) wide, housed in a sturdily-built wheelcase and driven by water from a wooden launder carried on eight stone pillars. The pillars are far from vertical, and the three nearest the wheelcase are heavily buttressed to prevent collapse.
In 1891 a sale document listed two planing tables, eight saw tables and one dressing machine, but modern use of the roofless building as sheep pens has obliterated the evidence of their layout. It is thought that a single line shaft ran the length of the mill, driven from a ring gear on the waterwheel. Raw material came into the mill on the north west side, waste was removed through waste holes along the south east wall, and finished products were stored in an external stack yard at the north end of the north east side, whence the exit tramway led off down Cwmorthin. A small extension at the south west end housed a smithy, the hearth still intact.
W J Crompton, RCAHMW, 22 October 2008.