Two rows of two-storey buildings, constructed from sawn slate blocks, face each other across the tram route to the waste tips at the head of Cwmorthin. The southern block consists of 6 units and was built in three stages, all probably complete by 1866. The westernmost unit was a stable with tack room above. The next was probably built as a barrack, but became the quarry office with the room above for the foreman. The rest were barracks, all with fireplaces, the upper rooms reached by external stairs on the south side.
The north range, consisting of four units, was built in one stage probably in the 1890s; it is not shown on the 1st edition 25-inch O.S. map of 1889. The westernmost ground floor room had four fireplaces and was probably a drying room. The next was a fitting shop, with the upper floor removed, replacing the earlier fitting shop at the west end of the mill (NPRN 408866). The next two were a store and another drying room, with barracks over, but by the 1920s all were stores.
W J Crompton, RCAHMW, 6 May 2009.