Cockhill Smelt Mill 1906

Cockhill Smelt Mill 1906

Bylands and Fountains abbeys both had mines on Greenhow and Coldstones Hills by the twelfth century. The latter’s mines were still active at its dissolution in 1539. Mining continued through the 17th century, but by the 1740s shafts were getting deeper and were troubled by water. To remedy this, Thornhill’s Level was driven from Brandstone Beck towards Greenhow village. This provided some relief for Waterhole Vein, but not mines further south. In the late 18th century, therefore, the Greenhow and Coldstones veins were split into two groups and a level was driven from Brandstone Beck to drain each of them.

In 1782 Overend & Co. began driving Gillfield Level south through alternating beds of sandstone and shale, which dip steeply to the north, until it entered limestone and cut Waterhole Vein. This had already been worked, from deep shafts and Thornhill’s Level, into the top of the limestone and much of the ore had probably gone. In the 1930s miners were able to get fluorspar from the old lead stopes. The level continued east on the vein for 120 metres until it turned south onto Sun Vein. Only part of the workings on the latter, in the form of a large stope, are now accessible. The mineralisation was soon cut off by a gulph, however. Gulphs, which are common on Greenhow veins, are large, natural voids which have been filled with clay. They were difficult to tunnel through and even harder to keep open because more clay was squeezed back into the workings. Gillfield, or North Coldstones, grant was merged that for Cockhill early in the 19th century.

Cockhill Level, about 150 metres WSW of Gillfield Level, was begun by Cleaver & Co. around 1783. It was also driven south to Waterhole, here called Cockhill, Vein and followed it west. A branch ran south-east, under the former Miners Arms, to the Sunside veins, which carried payable ore. By the 1830s the Sunside workings had reached Sun Vein, well to the south of Gillfield Level, and found a good oreshoot. It went under the level, however, and so a chamber was made from which an underground shaft was sunk to work it. A steam pumping engine and a set of boilers were also built in the chamber. Smoke from the latter escaped to the surface through old workings. The vein was getting poorer by 1838 when the chimney shaft collapsed, forcing the abandonment of the under-level workings.

On the west branch, Greenhow Rake proved rich for ore, which was also eventually followed under the level. In the late 1850s an engine chamber was excavated and an engine and boilers put in it for pumping from an underground shaft. This shaft was 40 fathoms deep in 1881 when worked ended – reputedly because a broken pump rod allowed it to flood. During a brief reopening by Bewerley Mines Ltd in 1925, one of the old boilers, supplemented by another at the top of the chimney shaft, was used to drain it to the 30 fathom level which was blocked.. This and the cost of pumping a high volume of water led to the abandonment of the scheme.

At first both Gillfield and Cockhill Levels had their own smelt mills, but the former’s, which stood 50 metres south-west of the entrance, was soon closed. The mill at Cockhill is usually shown with two ore-hearths and a roasting furnace. Nevertheless; one of the hearths must either have been a slag-hearth; or been capable of being converted to one. Each hearth had its own flue; which ran to two chimneys on the hill; about 40 and 60 metres respectively; south of the mill.

See: Gill, M.C. The Greenhow Mines (British Mining No.60, 1998)

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