Stenna Gwyn Mine (Stennagwyn Mine), Foxhole, St Stephen-in-Brannel, Cornwall, England, UKi

Regional Level Types
Stenna Gwyn Mine (Stennagwyn Mine)	Mine
Foxhole	- not defined -
St Stephen-in-Brannel	Civil Parish
Cornwall	County
England	Constituent Country
UK	Country

An ancient underground mine which ceased work shortly after 1804. An attempt may have been made to re-open it in 1880 when a return of 1 ton of black tin is recorded. Online court records show a dispute over unpaid bills for this period.

Stennagwyn is referred to under a number of different spellings including Stannagwyn and Stenna Gwinn which was used repeatedly by William Gregor in his correspondence regarding his research on Wavellite and Fluellite.
When working, Stennagwyn had china clay works immediately to the north and south. North of the mine, the works eventually became the West of England China Clay Works which has been cleared and the site is now occupied by the currently active Goverseth Plant. Immediately to the south was the North Carloggas China Clay works. The china clay works in the close vicinity of Stennagwyn were amongst the first to supply materials to the fledgling potteries in Stoke on Trent.

In the early 1980's there were at least two remaining chimneys from Stennagwyn Mine together with the foundations of a building. The chimney immediately behind the terrace of cottages had the base of a small building nearby. Unfortunately, since then, the area has been levelled to provide a football pitch, clubhouse, day center for young children and a static caravan park. Everything behind the terrace has either been flattened or pushed into a single heap. The one remaining collapsed chimney is the only feature listed by Herring & Smith (1991). Even the name Stennagwyn has been removed from some modern maps although the farmhouse immediately to the south of the mine site still keeps the name.

With so much happening in this relatively small area, it is impossible to find any original features in situ. The 24-inch map of 1908 shows extensive dumps that are now all lost.

Beer (1988) reports that the mine was worked from two shafts, adit level and a large openwork. None of this can be found today. One of the pipes going under the railway may take water from an adit? Industrial archaeological features can be viewed from the railway line. The locals have forced a footpath across the site, including the seldom used railway track, to link Goonamaris with the convenience store in Foxhole.

Carpholite supposedly collected here in 1952 by Arthur Kingsbury (1906-68) is now considered unlikely. This is one of a number of likely or definitely falsified Kingsbury localities. In his paper of June 1955, Sir Arthur Russell noted, "Many years ago the writer of these notes attempted to enter the adit, but found it impossible unless the water be diverted. However, in the summer of 1948, while we were showing a party of the International Geological Congress the Stenna Gwyn mine, my friend and colleague Mr. Arthur Kingsbury had the good fortune to find a specimen showing several well-defined crystals of fluellite in a block of vein-stuff built into the wall of a small ruined building on the mine."

Crystals of lustrous, blue fluorapatite from this locality are often on pegmatitic matrix (orthoclase, quartz, +/- tourmaline) suggesting these specimens occurred in a felsic pegmatite in the mine workings rather than a hydrothermal tin lode.

Geochronology

Geologic Time				Rocks, Minerals and Events
Phanerozoic
	Paleozoic
		Permian
			Guadalupian	ⓘ Major polymetallic mineralization ~270 Ma Cornwall, England, UK
			Cisuralian	ⓘ Porphyry dikes intruded (latest age) ~275 Ma Cornwall, England, UK ⓘ Greisenization (latest age) ~280 Ma Cornwall, England, UK ⓘ Porphyry dikes intruded (earliest age) ~280 Ma Cornwall, England, UK ⓘ Formation of metallized pegmatites ~285 Ma Cornwall, England, UK ⓘ Greisenization (earliest age) ~285 Ma Cornwall, England, UK ⓘ Emplacement of major plutons ~295 Ma Cornwall, England, UK

Other Regions, Features and Areas containing this locality

References