Carnglaze Slate Caverns

Carnglaze Caverns

Useful Information

Location: St Neot, South East Cornwall.
In the valley of the River Loveny, a tributary of the River Fowey about half-way from the A38 trunk road and St Neot village. North of A38, 3 km south-east of St Neot, between Liskeard and Bodmin.
(50.472690, -4.556406)
Open: JAN to JUL Mon-Sat 10-17.
AUG Mon-Sat 10-20.
SEP to DEC Mon-Sat 10-17.
Last tour 1 h before closing.
Fee: Adults GBP 8, Children (6-18) GBP 5, Family (2+2) GBP 22.50.
Groups: reductions for prebooked groups.
Classification: MineSlate Mine
Light: LightIncandescent Electric Light System
Dimension: T=10 °C.
Guided tours: D=45 min., L=100 m, VR=15 m.
Photography: allowed
Accessibility: partly wheelchair accessible
Bibliography: E. A. C. Pascoe (1984?): The Slate Caverns at Carnglaze, St Neot, Cornwall, 16 pp, 6 photos.
Address: Carnglaze Slate Caverns, St. Neot, Liskeard, PL14 6PG, Cornwall, Tel: +44-1579-320251, Fax: +44-1579-321571, Mob: +44-7768871641. E-mail: contact
As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then.
Please check rates and details directly with the companies in question if you need more recent info.


1603 slate quarry began on the surface.
1800? underground working commenced.
1833 first written reference in Parochial History of St Neot.
1903 underground working finished.
1937 the dumps inside the mine were turned over in search of building stone.
1939-1945 used as storage for vast quantities of rum for the Royal Navy. Bats left the mines as they could not tolerate the strong fumes given off by the rum barrels.
1973 opened to the public.


Carnglaze is only a kilometre from the slate / granite boundary and the slate in common with most of the Mid Devonian period slates, has no fossils. It is essentially blue in colour, varying noticeably from the greyer slates of North Cornwall which have been quarried for so many centuries at Delbole. The heat from the cooling granite has altered the slate making it distinctly pink and soft. Further away from the granite at Carnglaze the slate is hard, blue and well cleaved slate beds which provides material which can be split into very thin slices making a durable and light material which is ideal for roofing purposes.
Text by Tony Oldham (2002). With kind permission.


To the left of the entrance is a thin vein of tin. It provides a good opportunity to the way in which the tin lodes in Cornwall run through the surrounding country rock. Just inside the entrance are the foundations of an engine mounting. This was used in 1937 to haul up loads of building stone. A long flight of steps lead down to the floor of the first chamber this is 90 m long by 15 m wide and up to 6 m high, this was the old rum store. It is regularly used for concerts and will seat 300 people. Its fine acoustics make it ideal for all musical events. At one point is a pool of water, so clear that it is difficult to believe that it is 2 m deep. In the next chamber is the famous underground lake called The Blue Grotto of Capri. This is 9 m deep. Everywhere there are splashes of colour, red, orange and yellow, these are caused by the iron oxides in the rock. There are even some small straw stalactites.
Text by Tony Oldham (2002). With kind permission.