Rhosydd Slate Quarry is 4 miles from Blaenau Ffestiniog and 8 from Porthmadog. The area is mountainous and the main surface workings are at Bwlch Cwmorthin, a high pass separating the valleys of Cwm Croesor and Cwm Orthin. It had a working life of approximately 80 years and its demise came about through the drop in demand for slate. The output of the quarry has been estimated at 220 million slates and its waste tips contain over 2 million tons of rock.
Initially slate was sent by pack horse via Moelwyn and Cwm Maesgwm to be shipped by the Ffestiniog Railway at Penrhyndeudraeth. From 1864 connection was made to the newly opened Croesor Tramway. This was along a high tramway and a parabolic incline nearly 800 ft. long
The earliest workings recorded at Rhosydd date back to the 1830s when small hilltop excavations were made. By the 1850s quarrying had moved underground. By 1883 the quarry had become on of the largest underground workings in Wales outside of Blaenau Ffestiniog, 14 floors underground containing 170 chambers and shipping 5616 tons of finished slate.
The quarry was operated by a string of different owners each developing and enlarging the workings. The ups and downs of the slate trade, the difficulties of raising capital, geological problems and dangerous underground working practices also brought periods of closure and industrial unrest. Peak output occurred in the 1880's when over 6000 tons per year of saleable slate was mined. This was also the period of greatest employment when over 200 workers were engaged.
A major blow to the quarry occurred in 1900 when the "Great Fall" occurred underground, in the south eastern section of the workings. This destroyed a large part of the most profitable reserves. From this major blow the quarry never fully recovered. The first world war brought about a period of complete closure followed by reopening in 1919 and a brief flurry of activity. Slate production ceased in the early 1930s, although the site was not abandoned until shortly after World War II.
As Rhosydd was quite remote from Blaenau it was normal practice for the quarrymen to barrack or lodge at the quarry. They would arrive early on the Monday morning carrying enough food to last through the week. Unlike some of the other Ffestiniog quarries there was no such thing as a quarrymen's train. To get to work entailed a hard walk, in all weathers, over rough mountain tracks. The working week lasted until Saturday lunchtime.
Life in the barracks at most quarries was uncomfortable but at Rhosydd conditions were generally considered the worst in the industry. They were overcrowded, damp and squalid, there were no washing facilities apart from the nearest stream. The earliest barracks were on level 4 and were probably occupied from 1859 to 1899. The later barracks on either side of the "street" on level 9 came later. The southern row being built in the 1860's and the northern side added after 1890. Although it gives the appearance of a street the space between the two accomodation blocks only carried a tramway for tipping rubbish. Over the years the number of men barracking declined. Some men preferring to walk to work each day rather than put up with the appalling conditions. Living conditions for the men with families were somewhat better as the quarry had built terraced accomodation in Cwmorthin.
Conditions underground were both primitive and basic, particularly when compared to Rhosydd's near neighbour - Croesor quarry - which led the industry in innovation. Electric lighting was found only in the main tunnels underground and all the actual mining took place using candle light only. Whereas other quarries had special tunnels for the men to reach the workings, in Rhosydd they had to share the tunnels and inclines with the tramways. Despite all this the quarry had a very good safety record, although from 1876 - 1885 the average lifespan of a Ffestiniog quarryman was only 44 years.
Croesor Quarry is connected to the nearby Rhosydd Quarry by a tunnel that was built to aid surveying and settle boundary disputes. Croesor Quarry served by Croesor Tramway. It has a single adit in the hillside and ceased operation after a hundred years in 1930 having produced 11,000 tonnes of finished slate annually at its peak.
Croesor Quarry is notable amongst Welsh slate quarries for being almost entirely underground, with no significant surface workings. It was rare in its extensive use of forced air ventilation instead of the more common natural ventilation used in most slate mines. It also generated relatively small external waste tips compared with the volume of finished slates produced; this was largely achieved by back-filling underground chambers with waste once they were exhausted.
Croesor Quarry was initially worked from 1846 until 1878. From 1864 onwards, the quarry was connected to the slate wharfes at Porthmadog by an incline to the head of the Croesor Tramway.
Blaenau Ffestiniog Slate Quarries