MSO11639 - Treborough Quarries (Monument)

The quarry produced Treborough slate and was owned by the Trevelyans of Nettlecombe Court. It is recorded as providing 2000 slate tiles for Dunster Castle in 1426. It ceased production in 1938; the original quarry became a rubbish dump.

Was an important quarry producing Treborough slate. [1] OS map marks tunnel under road to waste tips. [4] The 1st Edition Ordnance Survey map marks the tunnel route and also shows a smithy on the site. [5] 'Tramway' also marked on old Ordnance Survey map. [6] This is recorded as a source of material for construction in Somerset and Exmoor by English Heritage. Stone was extracted for around 500 years, not closing fully until 1938. Ilfracombe Slates were extracted at this site, which were quite waved in surface, but sufficient for roofing, doorsteps, cisterns and flooring. Also extracted was sandstone, which was used in local building. The quarry provided slate for Dunster Castle in 1426. [7] The last slate quarries in Devon ceased trading in the early 20th century and Treborough quarry in Somerset closed in 1938. In the Ilfracombe Slates Formation (Middle Devonian) the quarries at Treborough (Treborough slates) were a well known source. Howe commented on their quality in 1910; "‘... the Devonian strata in north Devon and Somerset have afforded rough slates strong and sound, but with a rather wavey cleavage surface, and not capable of being split at all thin. They have been worked in a small way about Countisbury and Treborough, in the Brendon Hills. As a rule these slaty rocks are too much crinkled and folded to make good slate." [8] In 1975 the site was being used as a rubbish dump by the local councils. The slates at Treborough are exceptional in the area as it is the only source of high quality slate, and provided slates for the roofs on the Brendons. In the 1790s the quarry belonged to the Luttrells, with the site managed by Thomas Reynolds, and did good business, with slate sold to dealers who often received a discount for cash. Gunpowder was used for blasting. [9] An article about the quarry includes a photograph of the interior, showing the cutting shed and stables in c. 1900. The site was owned by the Trevelyans of Nettlecombe Court. An early reference to the site is made in 1426, when 2000 slates were provided to Dunster Castle. The original quarry face was not exhausted until 1863, when a new supply of slate was sought to the west of the main workings. The quarry was abandoned in or just before 1890 but was reopened in 1894, before again closing in 1910. It was once again reopened in 1914 to 1938. The tramlines and wagons went for scrap in World War Two and some of the buildings were pulled down. After the war the spoil heaps and suitable slopes were planted with conifers, although some of the ancient coppiced woodlands remained in 1983. The original deep quarry was used as a rubbish dump for West Somerset but the main working area was preserved as a Conservation Area for both its wildlife and industrial archaeological remains. [10] Walter Raymond described how the quarry appeared towards the end of its use. [11] The existing remains mostly date from the 19th and 20th century exploitation of the outcrop. The slate is of the Devonian Morte Series and is generally of poorer quality than that from Cornwall and Wales. The main quarry pit is centred at ST 0155 3675. It was 240 by 130 metres and so deep that a tunnel was constructed to convey the rock from the quarry face to the dressing area. A small spoil dump lies to the north of the main pit, 110 by 60 metres in size and centred at ST 0150 3683, the main spoil dump is 270 by 160 metres and runs from ST 0130 3702 to ST 0142 3683. Tramways link the quarry pit, processing area and spoil dump. The quarry building all lie on this spoil dump. The tunnel emerges at ST 0140 3684 and the stone processing buildings were sited close to this point. A slate mill where the stone was cut stood at ST 0140 3685. This was powered by a water wheel, visible on an early photograph [12]. Water for the mill was collected in two stone lined feeder ponds (ST 0124 3661 and ST 0124 3664) and directed to the mill via a leat. The 1st edition 25 inch map shows further buildings on the end of the main dump at ST 0132 3692 and 0134 3693 and inside the main quarry pit at ST 0150 3675 [5]. A building by the track at ST 0145 3685 was the stables for the horses who pulled the trucks on the tramways and the house today known as Quarry House (ST 0147 3693) housed the quarry manager. A further quarry pit was dug to the west of the main pit some time after 1888. It is 100 by 50 metres and centred at ST 0120 3666. A large spoil dump 170 by 60 metres runs from ST 0124 3668 to 0127 3685. Tramways run from the quarry onto the spoil dump. A tramway 120 metres long linked this quarry pit to the main quarry buildings [6]. A smaller quarry lies at ST 0190 3680, it is 100 by 30 metres with two spoil heaps; tramways ran from the quarry face. The quarry appears to be disused by 1904 [6]. Access to these sites proved problematical. The information above is derived from past and current mapping; the quarry manager's house and the stable block remain as roofed buildings. A fine slate cistern lies by the stables. The status of the other buildings could not be ascertained. Limestone outcrops close to the slate vein, and four limekilns by the quarries are recorded under MSO11641. [13] This record was enhanced as part of the National Record of the Historic Environment to Exmoor National Park Historic Environment Record data transfer project. [14] The quarries are mentioned in a publication on the industrial archaeology of Somerset. [15]