Hafodlas Quarry

Overview

A Nantlle Valley slate quarry chiefly remembered as the site of the first steam pumping engine ever installed in the Welsh slate industry, in 1807 -- an innovation that ended in dramatic failure a decade later when the engine and two whimsies fell into the quarry pit.

History

Water-wheels and windmills were the standard means of pumping water from the Nantlle quarries until 1807, when Hafodlas Quarry became the site of the first steam pump ever used in the history of the North Wales slate industry -- a significant early step in the mechanisation of Welsh slate working, allowing deeper excavation than gravity-fed water power alone could support. The innovation proved short-lived: in 1817, the steam pump and two whimsies fell sixty yards into the quarry, and within a few days the workings were flooded.

Geology

Slate of the Nantlle valley, in ground wet enough that the first steam pumping engine in the Welsh slate industry was installed here in 1807.

Workings

Drained originally by water-wheel or windmill power, like the other Nantlle quarries, before the short-lived introduction of steam pumping in 1807.

Closure

In 1817 the steam pump and two whimsies fell sixty yards into the quarry and the works stopped within days. No closure date for the quarry itself is recorded.

What remains

Unknown.

Recorded claims

Individual factual claims, each attached to the source(s) that support it below. Where sources disagree, both are kept.

• In 1807 Hafodlas Quarry became the site of the first steam pump used in the history of the slate industry in North Wales, installed to keep the quarry free of water in place of the water-wheels and windmills used elsewhere in the Nantlle valley. ^1,2
• In 1817 the steam pump and two whimsies fell sixty yards into the quarry, and within a few days the workings were flooded. ¹
• The ambitious Cilgwyn and Cefndu Slate Company, then seeking to buy up quarries across the region, failed in an attempt to buy Hafodlas Quarry for £1,500 in the early 1800s -- Hafodlas remained outside its control while the Cilgwyn Company went on to acquire leases at Galltyllan, Tynyffridd, Hafodywern, Garreg Fawr, Manod, Moelwyn and Talysarn instead. ³

Photographs & further reading

Sources

1. (secondary) Historical aspects of the Welsh slate industry — D. Dylan Pritchard, via slateroof.co.uk
2. (secondary) Slate industry in the Nantlle Valley — Wikipedia
3. (secondary) The Financial Structure of the Slate Industry of North Wales 1780-1830 — slateroof.co.uk (D. Dylan Pritchard, Quarry Managers' Journal, December 1942)

Record created: 30 August 2026 · Last researched: 15 September 2026