The surface remains at Marriott's shaft present a complete contrast to those on Daubuz' and Pascoe's shafts. Both of these were equipped with traditional Cornish beam engines, whereas Marriott's was refitted, following a disastrous fire in1895, with more up-to-date engines. At the time of its closure in 1918 it was one of the best equipped shafts n Cornwall.. Much can be deduced from the field evidence and it is hoped that further protection will be given to this excellent site: in 1986 only the pumphouse was scheduled as an Ancient Monument.
The upper section of the shaft was 16 feet in diameter and contained two sets of 18 inch diameter plunger pumps and pitwork which delivered 1,600 gallons of water per minute. These were driven from an inverted compound beam engine with 40 inch and 80 inch cylinders. It was made by Hathorn Davey of Leeds and began work in 1899. The structure of the pump house adjacent to the shaft indicates the layout of this comparatively unusual type of beam engine: there is no solid bob wall as in other engine houses, since the beam operated beneath the floor of the pumphouse, pivoted within the house itself. The cylinders rested on the first floor which was supported by massive interior buttresses. In fact, only one of the two engines planned for the pumphouse was ever installed and the slot beneath the floor for the second beam is clearly visible.
Adjoining the pumphouse is the roofless boiler house which originally provided steam for the pump, winder, compressor, capstan and crusher engines. On closure, it contained six Lancashire boilers and a Green's economiser through which the flue gases passed to the integral stack adjacent to the pumphouse wall.
The winding house, to the east of the shaft, is a large square building with windows at first floor level only. This contained a horizontal cross-compound winding engine made by Holman Bros of Camborne. The engine had 23 inch and 43 inch cylinders mounted on plinths each side of the drum space: it is possible to tell from the mounting bolt holes the positions of the cylinders.In between the plinths was suspended a conical winding drum, whose diameter varied from 12 to 25 feet to give a maximum winding speed in the shaft of 2,000 feet per minute.
Marriott's shaft also housed pipe lines from the compressed air plant in the building west of the pumphouse. This contained a cross compound two stage plant made by Fraser and Chalmers, capable of operating thirty rock drills. The building consists of a solid concrete plinth to first floor level with a centre cut out and central flywheel recess. The plant layout can be deduced from the surviving concrete bases and the seven crow-holes each side give access to the holding-down bolts.
West of the compressor house is the solidly built base of the stone breaker. Ore was brought from the shaft head on an elevated, which also enabled waste to be taken to the dumps. Crushed stone was stored in hoppers on the stone breaker base before being taken by railway waggon to the two sets of stamps near Carnkie. The stone breaker was driven from a 16 inch Tangye horizontal engine in the building adjacent, which also powered a capstan to raise pitwork in the shaft when required.
Refs: The Basset Mines-Palmer and Neaverson.
See Also: SOUTH WHEAL FRANCES; BASSET TRAMWAY; BASSET MINES.