Goonvean China Clay Works - Engine House with Boiler-House and Detached Chimney

The Goonvean China Clay Works includes an engine house with a boiler-house and a detached chimney, dated 1910. This structure is made of granite rubble with brick dressings and features a slate roof with crested ridge tiles and gable ends. The engine house has a rectangular plan and is three stories high, with a symmetrical front gable end facing east. It has a central plank door flanked by sidelights and a round-arched fanlight with radial glazing bars, topped by four courses of brickwork around the arch, and a datestone set as a keystone. The first and second floors each have a central round-arched 12-pane sash window with brick arches. There are later additions on the left side, while the right side has a similar round-arched sash window on the first floor, with the ground floor window blocked. The left side features a large lean-to that serves as the boiler-house and a similar sash window on the second floor. At the rear, there is a doorway at upper ground floor level with a round brick arch and keystone, leading to a platform, along with a rectangular bob opening above, which is weatherboarded at the top of the gable and contains a cast iron beam housing. The chimney is circular in plan, tapered, and has a bull-nose moulding at the top as a cornice.

Inside, the beam engine remains intact. Originally built in the 1860s by Harveys of Hayle, it was relocated here from Goon Innis mine in St Agnes in 1910. The existing beam was cast in 1928 to replace a broken one and was produced by Holmans of Cambourne, making it reputedly the last beam of its kind to be cast in the world. The boilers have been removed. Only six Cornish beam engines survive, with a few more located outside the country, making this a rare early example.