|Date||20 October 2012|
|Location||Maenofferen Quarry, Blaenau Ffestiniog||SH 71295 46603; 53.00121°N, 3.91936°W|
Extraction of slate at Blaenau Ffestiniog has largely been from mine workings rather than open quarries, as the seams there are steeply inclined. Maenofferen is one of the many slate quarries in the area and was initially worked at the open-cast ‘David Jones’ section of the quarry. In 1861 the Maenofferen Slate Quarry Company was established and it leased the quarry from the landowner Lord Newborough. Maenofferen was acquired in 1975 by J W Greaves and Sons, founded in 1836 and owners of the nearby Llechwedd Quarry.
Originally, slate was transported from the quarry via the Rhiwbach Tramway, down a series of inclines, and then onto a wharf at Porthmadog by way of the Festiniog Railway. Product was conveyed by road from 1962, but use of the internal tramways continued into the 1980s.
Maenofferen was the last large-scale slate mine to operate in North Wales, with underground working coming to an end in 1999, at which time the surface structures at the processing complex were also abandoned. The mine had reached a depth of 1000 ft with a horizontal extent of up to a mile. Material from the waste heaps is currently being reclaimed on a limited scale to produce crushed slate, and underground chambers are being untopped in order to retrieve high quality slate from their supporting pillars.