Tresavean & Tretharrup Mine, Cornwall
Gwennap: grid reference SW721394
Notable minerals: Blende, Chalcocite, Chalcopyrite, Chlorite, Copper, Epidote, Erubescite, Fahlerz, Fluor, Galena, Goslarite, Hornblende, Magnetite, Melaconite, Pyrites & Tennantite.
The sett of Tresavean lies just to the south of the A393, at Lanner Moor on the southeastern fringe of Lanner. Tresavean was one of Cornwall's leading copper mines, later producing some tin as well. It included at one time or another Wheal Comford, Treviskey, Tretharrup, Bellvean, Brewer, Barrier and Trethellan Mines. The major shafts for the sett were: Magor's, Teague's, Devonshire, Treweeks, Wheal Boys, Willyam's, Old East, Old Sump, Caddy's, Curnack's, Harvey's Engine and Man Engine Shafts. Tresavean is bounded to the west by Wheal Buller; to the northwest by Copper Hill Mine sett - itself a former part of Wheal Buller; to the south by Penstruthal and to the east by the A393 Redruth to Falmouth road. Its nearest neighbours are West Wheal Damsel, Ting Tang and the mines of United Downs all about a mile away.
'One of the Great Mines of Cornwall', it is reported to have paid out more than £442,000 in dividends between 1811 and 1886.
The mine is thought to date from at least 1700 and probably earlier. Tresavean as we know it began in earnest about 1811, with production and development on a relatively small scale to start with. In November 1819 a group of investors and agents including Captain J. Martin, Captain W. Martin and J. Michell acquired the mine from R. Magor and J.J. Borlase. Production increased from an average of 267 tons per year in 1811-1818, to over 2150 tons in 1819 alone. Production remained between the 1200 - 2300 ton mark until the end of the next decade when over 3341 tons of copper ore were raised at a value of £25,923. Its most productive period was between 1820 and 1850, with total production of 233,372 tons. This made it second only to the mighty Dolcoath at Camborne. The vast majority of the ore produced was copper, for in its lifetime Tresavean only raised 103 tons of tin.
In 1830 over 5800 tons were produced selling at £7.07/ton. Production continued increasing to consistently over the 11,000 ton level each year until 1842. In 1833, 12739 tons of copper at over £8 per ton was sold. The proceeds, in excess of £102,000 were divided amonst the investors, with the dividends totalling £60,480. The ore produced was not only plentiful but of a high grade, the previous year Tresavean copper ore sold at £8.11/ton as against the county average of £6.01/ton. A new shaft was sunk in 1840 and named Harvey's Engine Shaft on its completion in 1843. A new 85-inch pumping engine with12' stroke was installed over the shaft whilst the old 60-inch pumping engine was offered up for sale. A 'man engine' was installed at the mine in 1842 - the first of its type in the UK. The man engine was powered by a 36-inch beam engine. Production remained relatively constant until 1843, when the 8682 tons of copper ore raised sold at only £4.776/ton. The fortunes for Tresavean were on the change. Production continued falling year on year as the price of copper fell to just £2.80 per ton in 1858. The mine now struggled just to break even and the decision was taken to sell the mine after the adventurers withdrew their support in 1858.
An attempt was made to form a new company later that year but it came to nothing. In 1860 another attempt was made to resurrect the mine. This time the company was a little more successful. The company 'Tresavean and Tretharrup' asked the landowners J. Wentworth Buller and J. J. Rogers for a new 21-year lease to work the south lode which was granted. The new concern possessed a 24-inch engine that worked as part punping, part crushing and part winding engine. The new company produced small amounts of copper and some tin until 1872 but once again this venture came to nothing. A further attempt to reopen the mine in 1876 was again unsuccessful.
In mid 1881, a new company calling itself 'Tresavean Mines Limited' was formed. The head office was in London and the consortium was led by Sir. G. Innes. A new engine house was constructed over Harvey's shaft and a 90-inch pumping engine installed in it to de-water the mine. The chimney erected was the tallest in Cornwall at 150 feetThe new owners also purchased a 32-inch stamps engine and a second hand 24-inch whim engine from Pendarves United Mines. For the next 2 or 3 years the mine continued to invest in new machinery including a crusher from Belowda Mine, near St. Austell. No copper and only small amounts of tin were sold and the new owners soon found themselves in dire financial straits. In the four years since they had taken over the new management team had spent over £65,000 with little to show for it.
Late in 1885, a new compny made up of Tresavean Mines Ltd. and Old Shepherds Mines Ltd., East Wheal Rose Ltd. and Mount's Bay Consols Ltd. was formed. It was to be known as Shepherds United Mines Limited. Within the year this venture had failed too. The machinery was offered for sale in December 1886. The pumping engine from Tresavean was sold to Wheal Grenville near Troon, who needed a good pumping engine to dewater Fortescue's Shaft. Later on this engine was purchased from Wheal Grenville and set to work on Cook's Kitchen shaft of South Crofty. There was a brief period of working between 1907 and 1928 but Tresavean never recaptured the heady days of the previous century. The copper was gone and the tin was not produced in sufficient quantities to make the mine viable. There is one final claim to fame however, it was during this time that the deepest shaft on the mine achieved 2,660 feet - once again second only to Dolcoath. For more information on production dates and so on please see Roger Burt's excellent book Cornish Mines: Metalliferous and Associated Minerals, 1845-1913 (Mineral Statistics of the United Kingdom, 1845-1913).
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Other nearby mines and their main ores
Trethellan (approx. 0.7 km; COPPER)
Penstruthal (approx. 1.3 km; COPPER & TIN)
Pennance (approx. 1.5 km; COPPER & TIN)
West Wheal Damsel (approx. 1.6 km; COPPER & TIN)
United Mines (Clifford Amalgamated) (approx. 1.7 km; COPPER & TIN)
Ting Tang (approx. 1.8 km; COPPER)
South Buller & West Penstruthal (approx. 1.9 km; COPPER)
Cathedral Mine (approx. 2.1 km; COPPER)
Wheal Squire, United Mines (approx. 2.3 km; COPPER)
Wheal Damsel (approx. 2.4 km; COPPER & TIN)