Dolcoath mine

Dolcoath mine (Cornish: Bal Dorkoth} was a copper and tin mine in Camborne, Cornwall, England, 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. The site is south of this road.

The mineral rights were owned by the Basset family of Tehidy who are recorded on a deed in 1588 as leasing the ground to a family called Crane. By 1720 the mine was being worked for copper, and it was almost 300 feet (91 m) deep in 1746, when William Borlase called it a "very considerable mine". In 1778 it was nearly 600 feet (180 m) deep, according to William Price. The mine closed in 1787 because the large amount of copper ore that was being cheaply mined from Parys Mountain on Anglesey had depressed the price. However the price of copper slowly recovered and the mine reopened in 1799.

Of around 470 copper-producing mines in Cornwall and Devon, Dolcoath became the fifth largest. But as depth increased the copper died out, and by 1832 the mine was in danger of closing. However the mine captain, Charles Thomas, was convinced that tin ore would be found deeper down and after disagreements with the shareholders his faith was repaid and the first tin dividend was paid in 1853.

By 1882 the mine had reached a depth of 2,160 feet (660 m) and had 12 miles (19 km) of tunnels passable by men and a further 40 miles (64 km) of old workings which had become unused and impassable. In 1893 there was a major accident at the 412-fathom level (see below). In 1895 it took men employed in the lower levels between 2–3 hours to go down and return to the surface, so they could not work more than 4–5 hours a day.

Dolcoath became the largest and deepest mine in Cornwall, with its principal shaft, known as New Sump Shaft, eventually reaching a depth of 3,300 feet (1,000 m) below the surface. The pumping engine that worked this shaft dated from 1815; a piece of the cast iron bob from this engine is preserved in the collection of the Trevithick Society. This engine originally had a 76-inch-diameter (1,900 mm) cylinder, but this had to be replaced with an 85-inch (2,200 mm) cylinder when it was not powerful enough to cope with the deepening shaft. The rebuilt engine was so large that there was not enough room in the engine house for the stairs, so a unique wooden extension was built on the back to house them.

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