'Old Merioneth Vein'

The Llechwedd slate quarry in Blaenau Ffestiniog was opened in 1846 by J. W. Greaves.  The search for slate at Llechwedd almost ruined Greaves who, having already spent £25,000 on exploring the quarry site by 1849, was refused further loans by the banks. Without that money, Greaves was unable to pay his men and the whole venture was on the brink of ending in expensive failure. Luckily, a handful of loyal men shared Greaves’ belief in the presence of slate and continued to work without pay, searching for the illusive slate.  A few weeks later, a large vein of slate known as the ‘Old Merioneth Vein’ was found.

Upon the discovery of the vein at Llechwedd, work was done to connect the quarry with the Ffestiniog Railway which had opened in 1836. An incline was built to the quarry and this work was completed in 1848.

Growth, development and decline

The railway allowed the tonnes of slate produced at Llechwedd to make the journey to Porthmadog and then by sea around the world. In 1851, 2900 tonnes of finished slate was produced at the quarry, this rose to over 7600 tonnes by 1863.  Such was the demand for the Llechwedd slate that a dedicated wharf was built at Porthmadog in 1853 to allow the fleet of sailing boats to take the slate to the markets.

In 1890, Llechwedd quarry made a ground-breaking move and began using electrical power for its quarry machinery, generating its own hydro-electric power thanks to the high rainfall in Blaenau Ffestiniog.

Like the rest of the slate industry in north Wales, the Llechwedd Quarry suffered from the slump in trade during the first decades of the twentieth century.  The Llechwedd Slate Caverns were opened to the public in 1972 but unlike the other quarries of the area, mining operations continue at Llechwedd.