Water Balanced Incline and Drumhouse

Cadw's description

Location

Aberllefenni quarry lies on the NW branch road leading off the Aberllefenni to Aberangell road. The incline lies back c150m SW of the road.

History

The winning of slate slab at Aberllefenni appears to have begun as early as the C14 in the upper level of Craig Hen-gau, and lower levels were successively exploited, there being some record of slate production in the C16. In the C17 it was in the hands of the Lloyd family, passing to the Campbells in 1725, and, in 1801 to the bankers, Hoares. In 1870 it had an innovative manager, R Hughes, who was responsible for its then success. There were as many as 5 inclines, leading down to the slab mill on the valley floor. The Aberllefenni Slate Quarries reached their maximum production in the 1880s when some 183 men were employed, the output being 4,814 tons (4,891,024kg) in 1883. The water balance incline was one of two, and probably dates from the 1880s.

Exterior

The drumhouse is at the top of the incline between levels 5 and 6 of the quarry. It has gabled walls rising to a pitched roof, now lacking slates, with an internal offset carrying bearing beams for the drum shaft. The drum is c1.6m in diameter, 2.76m long between iron disks flanges, and is battened with timber. It has a rim band brake operated from an extended lever at the S end. The twisted steel cable is 25mm in diameter and secures the riveted iron plate water vessel, 1.86m x 2.16m x 1.65-0.63m deep mounted on a wooden frame on two axles with curved spoked flanged wheels engaging with top-hat section rails. These are spiked to timber sleepers set flush into the slate-on-edge surface of the incline. A water delivery pipe, 78mm in diameter, passes through the drumhouse to discharge over the water vessel. At the side of the drumhouse there is a ruined lean-to.

Reason for designation

The incline is of particular interest for the unusual use of water to balance the slate cars, and is included as a particularly well preserved example of this type of internal transportation system, and one which clearly illustrates the methods employed by the C19 slate industry.

Scheduled Ancient Monument ME185(GWY).