Calvert's Engine
The winding engine was installed in 1845, in which year production began from the 55 yard No.3 Rhondda seam.
[4] Winding was carried out with an iron flat chain, with wooden blocks through the links.
[6] Steam was supplied from an egg-ended boiler at a pressure of between 8–10 pounds per square inch (55–69 kPa).
[11] At the end of the colliery's working, the Inspector of Mines' list of 1896 shows 489 employed there.
A widely known postcard of 1912 shows the hose overgrown with ivy, but the engine beam still in place.
[7] It is not clear if this is an error, in either direction, or that the engine was re-started for a time, possibly during World War I and then closed soon after.
[13] This South Wales and Monmouthshire School of Mines[iv] was based in Forest House, built by the Crawshay family on the site of Fforest Isaf farm at Trefforest, Pontypridd.
Around 1920 the engine was removed from the derelict colliery and re-erected nearby in the grounds of the School of Mines.
The hooked rod from the right is driven by the eccentric. When engaged, it rocks the valve arbor, the square shaft, back and forth. Bellcranks behind the shaft work the valves via the vertical pullrods.