Ancient Monuments

History on the Ground

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Water Balance Incline at Aberllefenni Slate Quarry

A Scheduled Monument in Corris, Gwynedd

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Latitude: 52.6746 / 52°40'28"N

Longitude: -3.824 / 3°49'26"W

OS Eastings: 276769

OS Northings: 310102

OS Grid: SH767101

Mapcode National: GBR 93.4H4C

Mapcode Global: WH687.719F

Entry Name: Water Balance Incline at Aberllefenni Slate Quarry

Scheduled Date: 11 June 1998

Source: Cadw

Source ID: 3960

Cadw Legacy ID: ME185

Schedule Class: Transport

Category: Incline

Period: Post Medieval/Modern

County: Gwynedd

Community: Corris

Traditional County: Merionethshire


The monument comprises the remains of a water-balance up-haulage incline for transporting slate waste to tips on the hillside. The incline survives almost intact, with its drum house and drum, brake mechanism, wire rope, and tank waggon.

Slate quarries have been operating in the Aberllefenni area since 1500 or earlier. The quarries probably began working regularly in 1810 but became most active after investment in rail transport and mills in the 1870s. Production of high quality slate slabs was from adits and rubble had to be dumped in a restricted gorge. Water-balance inclines enabled tipping on the high sides of the gorge by using water to raise loaded waggons by counter-balance.

The monument is the best surviving example of a water-balance incline in the Welsh slate industry. It is of national importance as a well preserved area within a slate quarry, which contains important evidence of slate quarrying, preparation, transport and infrastructure. Inclines may be part of a larger cluster of industrial monuments and their importance can further enhanced by their group value.

The scheduled area comprises the remains described and areas around them within which related evidence may be expected to survive.

Source: Cadw

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