Wheal Gorland
Encyclopedia
Wheal Gorland was a metalliferous mine located just to the north-east of the village of St Day
, Cornwall
, in the United Kingdom
. It was one of the most important Cornish mines of the late 18th and early 19th centuries, not only for the quantity of ore it produced, but also for the wide variety of uncommon secondary copper minerals found there as a result of supergene
enrichment. It is the type locality
for the minerals Chenevixite, Clinoclase
, Cornwallite and Liroconite
.
and Consolidated Mines
. However in 1865 Thomas Spargo wrote "now part of St. Day United; idle".
In the early 1790s Wheal Gorland was connected to the Great County Adit
and its own existing shallow adits were adapted to drain into this deeper adit. Records show that between 1815 and 1851 the mine produced 40,750 tons of 7½ % copper ore, 15 tons of black tin
, and 18 tons of arsenic
. Much fluorspar was also produced, and gold was reputedly found in the gossan
. In 1852 the mine was taken over by the St. Day United Group of mines and it became the main site for maintenance of the Great County Adit, but by 1864 it had been abandoned.
The mine was reopened in 1906 when Edgar Allen and Company
reworked the stope
s and the dumps for tin and tungsten ores. It sold 164 tons of tungsten ore and 18 tons of black tin before closing, for the last time, in 1909.
Since 1988 the site has been designated as a Site of Special Scientific Interest
because of the variety and quality of lead and copper minerals that have been found in the mine dumps. A condition summary compiled on 21 July 2010 reported that the site was in an ″unfavourable declining condition″ because an earth science feature was obstructed and another removed. The summary further states that the vegetation on the remaining mine dump may also be affecting the mineral features of the site as new soil horizons
could affect chemical processes within the dump.
St Day
St Day is a civil parish and village in Cornwall, United Kingdom. It is situated between the village of Chacewater and the town of Redruth.St Day is located in a former mining area and St Day accrued considerable wealth from mining...
, Cornwall
Cornwall
Cornwall is a unitary authority and ceremonial county of England, within the United Kingdom. It is bordered to the north and west by the Celtic Sea, to the south by the English Channel, and to the east by the county of Devon, over the River Tamar. Cornwall has a population of , and covers an area of...
, in the United Kingdom
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
. It was one of the most important Cornish mines of the late 18th and early 19th centuries, not only for the quantity of ore it produced, but also for the wide variety of uncommon secondary copper minerals found there as a result of supergene
Supergene (geology)
In ore deposit geology, supergene processes or enrichment occur relatively near the surface. Supergene processes include the predominance of meteoric water circulation with concomitant oxidation and chemical weathering. The descending meteoric waters oxidize the primary sulfide ore minerals and...
enrichment. It is the type locality
Type locality (geology)
Type locality , also called type area or type locale, is the where a particular rock type, stratigraphic unit, fossil or mineral species is first identified....
for the minerals Chenevixite, Clinoclase
Clinoclase
Clinoclase is a hydrous copper arsenate mineral, Cu3AsO43. Clinoclase is a rare secondary copper mineral and forms acicular crystals in the fractured weathered zone above copper sulfide deposits. It occurs in vitreous, translucent dark blue to dark greenish blue colored crystals and botryoidal...
, Cornwallite and Liroconite
Liroconite
Liroconite is a complex mineral: Hydrated copper aluminium arsenate hydroxide, with the formula Cu2Al[4|AsO4]·4. It is a vitreous monoclinic mineral, colored bright blue to green, often associated with malachite, azurite, olivenite, and clinoclase...
.
History
The production of the mine was very inconsistent because of the sporadic distribution of its rich ore-bodies: in 1833 George Abbot wrote that it had made profits of over £300,000, produced 1,400 tons of ore per annum, and ranked third, in terms of profits, just behind Dolcoath mineDolcoath mine
Dolcoath mine was a copper and tin mine in Camborne, Cornwall, in the United Kingdom. Its name derives from the Cornish for 'Old Ground', and it was also affectionately known as The Queen of Cornish Mines. The site is north-west of Carn Brea. Dolcoath Road runs between the A3047 road and Chapel Hill...
and Consolidated Mines
Consolidated Mines
Consolidated Mines, also known as Great Consolidated mine, but most commonly called Consols or Great Consols was a metalliferous mine about a mile ESE of the village of St Day, Cornwall, England. Mainly active during the first half of the 19th century, its mining sett was about 600 yards...
. However in 1865 Thomas Spargo wrote "now part of St. Day United; idle".
In the early 1790s Wheal Gorland was connected to the Great County Adit
Great County Adit
The Great County Adit, sometimes called the County Adit, or the Great Adit was a system of interconnected adits that helped drain water from the tin and copper mines in the Gwennap area of Cornwall, in the United Kingdom...
and its own existing shallow adits were adapted to drain into this deeper adit. Records show that between 1815 and 1851 the mine produced 40,750 tons of 7½ % copper ore, 15 tons of black tin
Black tin
Black tin is the raw ore of tin, usually cassiterite, as sold by a tin mine to a smelting company. After mining, the ore has to be concentrated by a number of processes to reduce the amount of gangue it contains before it can be sold...
, and 18 tons of arsenic
Arsenic
Arsenic is a chemical element with the symbol As, atomic number 33 and relative atomic mass 74.92. Arsenic occurs in many minerals, usually in conjunction with sulfur and metals, and also as a pure elemental crystal. It was first documented by Albertus Magnus in 1250.Arsenic is a metalloid...
. Much fluorspar was also produced, and gold was reputedly found in the gossan
Gossan
Gossan is intensely oxidized, weathered or decomposed rock, usually the upper and exposed part of an ore deposit or mineral vein. In the classic gossan or iron cap all that remains is iron oxides and quartz often in the form of boxworks, quartz lined cavities retaining the shape of the dissolved...
. In 1852 the mine was taken over by the St. Day United Group of mines and it became the main site for maintenance of the Great County Adit, but by 1864 it had been abandoned.
The mine was reopened in 1906 when Edgar Allen and Company
Edgar Allen and Company
Edgar Allen and Company was a steel maker and engineer, which from the late 19th century was based at Imperial Steel Works, Tinsley, Sheffield, South Yorkshire...
reworked the stope
Stoping (mining method)
Stoping is the removal of the wanted ore from an underground mine leaving behind an open space known as a stope. Stoping is used when the country rock is sufficiently strong not to cave into the stope, although in most cases artificial support is also provided...
s and the dumps for tin and tungsten ores. It sold 164 tons of tungsten ore and 18 tons of black tin before closing, for the last time, in 1909.
Since 1988 the site has been designated as a Site of Special Scientific Interest
Site of Special Scientific Interest
A Site of Special Scientific Interest is a conservation designation denoting a protected area in the United Kingdom. SSSIs are the basic building block of site-based nature conservation legislation and most other legal nature/geological conservation designations in Great Britain are based upon...
because of the variety and quality of lead and copper minerals that have been found in the mine dumps. A condition summary compiled on 21 July 2010 reported that the site was in an ″unfavourable declining condition″ because an earth science feature was obstructed and another removed. The summary further states that the vegetation on the remaining mine dump may also be affecting the mineral features of the site as new soil horizons
Soil horizon
A soil horizon is a specific layer in the land area that is parallel to the soil surface and possesses physical characteristics which differ from the layers above and beneath. Horizon formation is a function of a range of geological, chemical, and biological processes and occurs over long time...
could affect chemical processes within the dump.