Phoenix United Mine, Minions, Liskeard, Linkinhorne, Liskeard District, Cornwall, England, UK
|Latitude & Longitude (WGS84):||50° 31' 26'' North , 4° 27' 1'' West|
|Latitude & Longitude (decimal):||50.52399,-4.45041|
|UK National Grid Reference:||SX265723|
|Other regions containing this locality:||Devon and Cornwall metalliferous mining district, England, UK|
|Köppen climate type:||Cfb : Temperate oceanic climate|
Mining first commenced in 1836 under the name of Cornwall Great United Mines, but was unsuccessful. Reopened about 1844 as Phoenix Mine, West Phoenix Mine was included within the set in 1875, after which the mine was worked as Phoenix United.
Most of dumps removed at closure, including engine houses, but Prince of Wales Shaft has complex of buildings associated with it.
Note on the mineral list: for "coeruleolactite" see references and information given for Planerite-Turquoise Series.
This mine is on the flank of Bodmin Moor beyond the crest of Caradon Hill where unlike South Caradon the country rock has largely been eroded away to expose the granite at surface and what country rock remains is significantly more altered by regional metamorphism.
As with South Caradon, in the early years of operation after 1824 Phoenix was a faltering concern with a number of ownerships and name changes. In 1852 however a rich copper lode was struck and for 10 years output approached that of South Caradon but then rapidly declined.
A simplistic notion of hypogene deposition was already well understood and this seemed to have been confirmed by the findings at Dolcoath Mine where the copper gave way to tin at the granite-country rock contact. There were indications of tin at Phoenix and tin streaming had taken place on both Caradon Hill and adjacent to the Cheesewring Quarry nearby on the higher moorland. Furthermore Cassiterite was being worked at nearby Marke Valley Mine lower down the hillside. Gambling on there being tin reserves at depth a controlling share in the mine was bought by William West, a mining engineer who was at the time working for the company.
His gamble paid off and the workforce at the mine tripled within a year so that in 1877 a peak production of 34000 tons of tin ore was brought to the surface. Production thereafter declined but continued for another 20 years.
In 1907 the Prince of Wales shaft with its magnificent engine house was commenced. It was however a financial disaster, finally reaching a depth of 200 fathoms but with only 95 tons of black tin produced over seven years.
To help interpret these figures it should be noted that tin ore typically yields 1-2% Cassiterite aka ‘black tin’. So from 1853 to 1913 approximately 16500 tons of black tin was produced from this group of mines. By that simple reckoning the 1877 production was between 340 and 700 tons of black tin from the 34000 tons of ore, which over the 20 years of peak production would indeed give a total output approaching the total of 16500 tons of black tin.
Similarly the 80 000 tons of copper ore raised at Phoenix United yielded around 6.75% copper, in other words 5400 tons of copper. Compare this to the peak year at South Caradon which in 1864 produced 5144 tons of copper from a 10% ore.
Adding to the above figures the volume of waste rock that was removed from shafts, adits and barren ground or wall rock to permit access then it is easy to see how the total amount excavated could readily reach ½ a million tons or more, little wonder then the extensive tips.
Whilst little surface evidence remains in the undergrowth down the slope from the tips there are buddles and leats and reservoirs.
45 valid minerals. 1 (TL) - type locality of valid minerals.
|Geologic Time||Rocks, Minerals and Events|
This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.
Click on geological units on the map for more information. Click here to view full-screen map on Macrostrat.org
|Permian - Carboniferous|
252.17 - 358.9 Ma
|Unnamed Igneous Intrusion, Carboniferous To Permian|
Age: Paleozoic (252.17 - 358.9 Ma)
Reference: British Geological Survey. DiGMapGB-625. British Geological Survey ©NERC.