Elliot Colliery Winding House contains an exceptionally large original horizontal engine as built in 1891 and modified to compound working in circa 1911. The colliery operated from 1883 to 1967 and was owned by Powell Duffryn until nationalisation in 1947. The East Elliot shaft was 5.5 metres (18ft) in diameter and sunk 1888-90 to 369 metres (1,212ft) on the Big Vein. West Elliot Pit was of 5.5 metres (18ft) diameter and identical depth, sunk in 1883-85.

The engine house is a two storey rusticated stone structure set on level ground above the east bank of the river. Both side elevations have six arched-windows and blocked doors, on the east the plaque above the door is inscribed 'East Elliot Pit 1891'. The south gable has a blocked door and window, and a brick arch at ground level. The north side faced the colliery shaft (indicated by a man-hole) and has a blocked arch and window at ground level, and also a secondary door. A first-floor door has an iron balcony outside it. The outside has the thin iron exhaust-chimneys. The large winding-drum is sunk into the floor.

The engine was originally a two-cylinder simple type and later it was converted to a compound with the addition of high pressure cylinders, 28-inch bore x 72-inch stroke. After rebuilding, the low pressure exhaust drove a turbine for generating electricity, then passed through a condenser and returned to the boilers. There is a 25 foot to 15 foot diameter drum of a type unique in Wales: a `diabolo' drum, which is a bi-cylindro-conical type but with the smaller diameter in the centre. This is the last survivor of the most sophisticated type of steam winding engine, a four-cylinder tandem compound by Thornewill & Warham, Burton-on-Trent.

The site was restored as a museum in 1993. It is now in permanent use and is more appropriately protected as a grade 2* listed building. The pithead baths block (NPRN 80465) also survived on site.

RCAHMW, 23 June 2011

Sources:
Site visit by B.A.Malaws, RCAHMW, 01 September 1993.
Brian Davies, Pontypridd Heritage Centre
Cadw Field-Warden's Reports). (Site entry by Stephen Hughes for Buildings of Glamorgan, John Newman, 1995)
Collieries of Wales, RCAHMW
A Guide to the Industrial Archaeology of South East Wales, AIA, 2003