Engine Hall of former Llantrisant Colliery

Location

Located to the N of Ynysmaerdy farmhouse.

History

Llantrisant or Ynysmaerdy Colliery was established by the Powell Duffryn Steam Coal company after World War I. It closed in 1942 following an underground explosion. It was constructed on the efficient modern model developed by the Powell Duffryn Company, with a single engine hall containing the main power equipment needed on the surface. The site is a particularly complete and impressive colliery complex, containing the engine hall, workshops and stores, ruined offices, a separate winding engine house, railway lines, tips, a long revetment wall, a reservoir, an an explosives store. It was associated with the planned housing estate at Ynysmaerdy.

The engine hall formerly contained 2 winding engines, fans and fan engines, compressors, generators and electrical switchgear.

Exterior

A large 2-storey gabled engine hall, 12 bays long and 2 wide, of rendered brick on a coursed sandstone rubble plinth, with red brick dressings. There are lower projections to the centre on both sides. It has a slate roof with a continuous glazed band on each side, terracotta ridge tiles and 5 conical ventilators. The windows have segmental heads with deep, stepped surrounds and pronounced keystones, all red brick, in typical Powell Duffryn house style. The large windows to the main (upper) floor are metal framed, 7 panes by 9, and the smaller windows to the ground floor are 7 panes by 3, or 3 by 3. There is an oculus to the N gable with stressed voussoirs. Red brick has been used for pilasters separating each bay to the front, a deep eaves cornice, and a string course at main floor level. The engine hall faced shafts on the E side and the penultimate bays either end had slots for winding cables. Between them, the eastern projection contains separate compartments for electrical gear and has a concrete cable support above. Two blocked round-headed openings in the S gable end formerly led into the fan housing.

Interior

The main floor has high clearance and is exceptionally light, with large windows and continuous rooflights. Two larger wells open into the floor below and an arcade leads to the rear projection. Pilasters down the length of the hall support a gantry for a 'Cargolift' travelling crane with driver’s cabin. The floor has red herringbone tiling, and there is a terrazzo floor.

Reason for designation

Listed as a monumental example of a Powell Dufryn common engine hall, and for group value in this unusually complete and impressive colliery complex.