Cwm Ebol Quarry

Overview

A small slate quarry a mile northwest of Pennal, worked from 1860 to 1906 through two successor companies and a final owner who also ran the nearby Gartheiniog quarry, whose old mill reservoir came close to catastrophic failure over a century after closure.

History

The Cwmebol Slab and Slate Co. Ltd began working the quarry on a modest scale around 1860, with an open pit and an adjacent mill powered by waterwheel; by 1870 local authorities were anticipating a railway extension to serve its expected output. Quarryman Jacob Davies was crushed by a falling rock and killed in the mid-1870s, and the original company failed in early 1874. A successor, the New Cwmebol Slate and Slab Co. Ltd, took over from 1875, built a new lower mill completed in 1876 under chairman F. Thompson and manager R. G. Elwes, and explored a second vein for roofing slate. By 1883 the quarry had passed to John Jenkins of Aberystwyth, who also owned the nearby Gartheiniog quarry and retained Cwm Ebol until its closure; production had fallen sharply by then, with just 257 tons raised in 1885. A reservoir on the Nant Cwm Ebol stream, built to supply water pressure for the mill's waterwheel and later a Pelton wheel, remained a source of danger long after mining ended: in June 2012, a landslip cracked the dam wall and blocked its sluice gates, causing water to overtop the structure and prompting the evacuation of the nearby village of Pennal (see Disasters, below). In its working life the quarry also suffered a second fatal accident, in 1894, when Hugh Owen was pulled into machinery while repairing a drive belt in the mill, and a serious injury in 1900, when a 19-year-old lost an arm during blasting and the quarry's manager was fined over the incident. Employment fell from 12 workers in 1898 to just 8 by 1903, and Jenkins faced rate-collection proceedings that same year. Slate left the quarry via a tramway -- originally 3 ft gauge, later converted to 2 ft -- running nearly two miles to a wharf at Llyn y Bwtri; from 1887 this terminated at the road instead, with slate transferred onward to the Cambrian Railways at Machynlleth, making Cwm Ebol, by one account, the last Welsh slate quarry connected only to a trans-shipment point rather than directly to a railway or a port. The quarry closed in 1906, and its machinery was advertised for sale the following year.

Geology

Slate a mile north-west of Pennal; the vein is not named on the record.

Workings

An open pit with an adjacent mill, powered first by waterwheel and later by a Pelton wheel fed from a dammed reservoir on the Nant Cwm Ebol stream; slate travelled by tramway to a road transfer point and onward to the Cambrian Railways at Machynlleth.

Closure

Closed in 1906 under John Jenkins's ownership; its machinery was advertised for sale in 1907.

What remains

The old mill reservoir survives and remains an active flood-risk structure, having come close to catastrophic failure in 2012.

The former quarry pit, mill site and its reservoir survive above Pennal.

Related mines

• Gartheiniog Quarry — Both were owned by the same man, John Jenkins of Aberystwyth, by 1883.

Disasters & major incidents

• Cwm Ebol Reservoir Dam Breach (2012)
  10 June 2012 · Surface / Tip Failure · 0 fatalities
  A landslip cracked the dam wall of Cwm Ebol quarry's old mill reservoir and blocked its sluice gates, causing water to overtop the structure and prompting the precautionary evacuation of the nearby village of Pennal.

Recorded claims

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

• Quarryman Jacob Davies was crushed by a falling rock and killed in the mid-1870s; in 1894, Hugh Owen was pulled into machinery and killed while repairing a drive belt in the mill; in 1900 a 19-year-old lost an arm during blasting, and the quarry's manager was fined over the incident. ¹
• Output had fallen to just 257 tons by 1885; employment fell from 12 workers in 1898 to 8 by 1903, and owner John Jenkins faced rate-collection proceedings that year. The quarry closed in 1906. ¹
• Slate travelled by tramway (originally 3 ft gauge, later 2 ft) to a road transfer point from 1887, then onward to the Cambrian Railways at Machynlleth -- by one account making Cwm Ebol the last Welsh slate quarry connected only to a trans-shipment point rather than directly to a railway or a port. ¹
• Located at about 52.597 N, 3.938 W. ¹

Sources

1. (secondary) Cwm Ebol quarry — Wikipedia
2. (secondary) Welsh village evacuated amid dam breach fears — New Civil Engineer

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