Former Lewis Merthyr Colliery Trefor pithead and headframe

The former Lewis Merthyr Colliery Trefor pithead and headframe is a significant industrial structure featuring a stone and brick pitbank topped with a wrought iron trussed corrugated roof, from which a lattice girder headframe rises. The pitbank is constructed from a plinth of rubble and rockfaced sandstone, featuring irregular openings and arches that provide access to service tunnels. The sides of the fan passage curve as they lead from the shaft to the fan house on the east side. While parts of the superstructure above the pit bank are made of brick, some of which are new, the cover building is primarily constructed of corrugated iron on a wrought iron frame, typical of collieries from this period. The site retains its airlock doors, heavy wooden guillotine gates, and knocking irons. The headframe, which rises through the roof, is of the wrought iron lattice girder type, supported by four splayed legs over the shaft and two sweeping supports extending from the axle of the sheaves to stone plinths against the north wall of the adjacent winding engine house, connected by diagonal braces. A maintenance platform surrounds the sheaves, with access provided by a ladder up the southwest leg. Inside the headframe, there is a later steel plate air lock.