Mr. Beauchamp's cobalt mine, Pengreep, Gwennap, Cornwall, England, UKi

Regional Level Types
Mr. Beauchamp's cobalt mine	Mine (Abandoned)
Pengreep	Mine
Gwennap	Civil Parish
Cornwall	County
England	Constituent Country
UK	Country

An 18th century cobalt mine, which was started around 1754 after an adit driven through Pengreep estate accidentally hit a cobalt-bearing lode. An account on this discovery and the short history of the mine has been given by Pryce (1778): "We have had but one cobalt mine that ever was distinguished by that name in this vicinity, which was discovered accidentally by Mr. Beauchamp, in an adit that he drove through some part of his estate at Pengreep in Gwennap. He discovered a lode of three feet breadth, which contained a branch of real cobalt; and it happening about the time when the Society of Arts, &c. [Society for the Encouragement of Arts and Useful Discoveries] offered a premium of thirty guineas for the best cobalt to be discovered in England, he was hounoured with the reward for his specimen, pursuant to the advertisement. It did not hold in depth, but soon deserted the pursuers; who were likewise very soon after obliged to suspend their search, by a prodigious influx of water to their workings."

The lode also carried bismuth ores: "In the same load, there is a good deal of bismuth, not only where the cobalt is, but so prevailing in other parts of the mine, that it may as justly be called a mine of bismuth as of cobalt" (Borlase, 1758). They were thrown on the dumps, until in 1775, a Dr. Albert Schlosser visited the mine and demonstrated a process to separate them from the cobalt ores (De La Beche, 1839).

According to Collins (1896 & 1912), quoting Borland (1758), nickel ores were found here in 1754. This made its way in numerous subsequent publications and is still widely considered today as the first report on the occurrence of nickel ores in Cornwall. Though, this report is a mistake by Collins: page 130 which he quoted from Borlase's book in 1896, does not mention any nickel ores but cobalt ores instead.

In 1958, the Atomic Energy Authority reopened the adit in search for uranium ores, but none were found. In the same year, the workings were visited by Hamilton Jenkin, who noted that the adit was about 300 feet long. He also suggested that the small burrow in a field about 200 yards SSE of the adit portal may be a shaft dump.

The grid reference marks the approximate position of the adit portal, as indicated by Hamilton Jenkin.

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