Former Llanbradach Colliery engine hall

A long single-storey gabled structure consisting of 3 parallel ranges oriented N-S, the W range shorter, but forming a 3-bay facade to the N. The N and W walls are of rubble sandstone with rock-faced dressings, the E and S walls are of snecked, rock-faced sandstone. The roof is replaced with corrugated metal sheets behind coped gables and with raised ridges. On the N side, the central bay is buttressed and has an oriel window with iron-frame glazing (blocked behind the glazing bars), below which is an inserted door for vehicular access. The L and R bays each have 3 stepped round-headed windows with iron-frame glazing, with lately added projections below in the L bay, and an inserted doorway and blocked segmental headed window below in the R bay.

The E elevation is buttressed and has 2 tiers of windows, grouped 3:4:4:4:3 at the lower level and 1:2:2:2:1 at the upper level, the upper windows having a continuous sill band. The windows are segmental-headed, and retain original iron-frame glazing at the S end but are mostly replaced at the N end, corresponding with the recent internal division of the building. Near the S end is an additional buttressed bay with a square window above the former opening for the winding cables, now blocked.

In the S elevation the central and E bays have oriels above an inserted wide doorway with blocked segmental headed windows to their R. The W range is set well back and has an oriel above an added lean-to.

The building has been subdivided into one large unit at the N end and 2 smaller units at the S end. Otherwise it is open to the roof and has wrought iron trusses, the valleys of the roofs carried on rows of steel uprights. The walls have a dado of brown tiles above which the walls are plastered with panelled pilasters and a moulded cornice. The central range retains, at the N end, a travelling crane on wrought iron columns and girders.