Chapel Mill

Chapel Mill

Chapel Mill is a china stone mill dating from the late 19th century, built on the site of a former grist mill and extended slightly later. It stands on Gwindra Road in St Stephen in Brannel. The mill comprises a main building with associated pan kiln, linhay, and ancillary structures. It is constructed of granite rubble with granite dressings, features cast-iron and wrought-iron machinery, and has a corrugated iron roof.

The mill follows a rectangular plan. Originally designed symmetrically, it had a central wheel-pit containing a large pitch-back waterwheel flanked by two pan rooms with round pans. It was later extended on the left to provide an additional round pan driven by the same wheel. The front elevation has a wheel opening flanked by two doorways. Access to the basement, which contains the gearing and drive shaft in an axial passage, is gained by two flights of stone steps to cross passages on the left of the wheel and by an end doorway direct to the central axial passage at the right-hand end. These basement passages have vaulted brick ceilings.

In front of the mill sits a rectangular reservoir. At an angle near its front on the left is the masonry support for the former launder from the leat. The rear of the mill contains roofless ancillary buildings arranged in sequence: four settlement tanks immediately behind the mill; a rectangular pan kiln with a round chimney on its left and a coal store on its right; the linhay for drying china stone behind this; and a walled yard containing the walls of buildings last used as a slaughterhouse. To the right of the mill stands the former mill keeper's cottage, dating from the mid-19th century at its front and incorporating an 18th-century partly cob house in its rear range, now roofless and not included in the listing.

The mill is single-storey over a basement. The left-hand doorway at the front is approached across a bridge spanning the winding access to the original basement cross passage. Another basement doorway to the left of this provides access to the pan gearing that was added. A window opening exists to the left-hand return towards the rear, with a central basement doorway underneath.

The interior has limewashed rubble walls and the original 11-bay queen strut roof structure, built in two phases with wider spacing in the bay where the building was extended. The mill contains three china stone pans: the two original pans are built of segments of dressed granite held together by iron restraint bands with threaded adjusters, with holes in the top of each pan wall that probably originally held safety rails. The third pan is constructed of brick and is unrestrained. A vertical drive shaft passes through the centre of each pan, driven via adjustable iron gearing from the main drive shaft in the basement. Above each pan is a large cross beam holding the remains of the top bearings for four rotating cast-iron gates, each originally holding three vertical timbers fitted with iron shoes for grinding china stone. The iron waterwheel is approximately seven metres in diameter, with wrought-iron arms (spokes) and cast-iron shrouds (segments). The remaining machinery, including drive shafts and cogs, is of cast iron; the bronze bearings have been removed.

The rear buildings were heavily overgrown at the time of survey, but their walls appear to survive to their full original height. Granite posts stand at the otherwise open front (rear-facing elevation) of the linhay.

Chapel Mill was used for grinding china stone, which was used to provide support to the china clay employed in porcelain manufacture. The mill also ground sand for use as an abrasive and ground feldspar. The mill is post-1880, as it does not appear on the 1880 Ordnance Survey map, and ceased working in 1953. Chapel Mill is the best-preserved and most complete example of its type surviving from the mills that served the Cornish china clay industry. It is the only example to have retained its machinery, making its survival of considerable importance.