Arn Gill is a ravine or gully containing a beck of the same name, near the village of Muker in Swaledale, North Yorkshire, England. The ravine and beck run steeply downhill from the stream's source in Arn Gill Head, and the beck disgorges into the River Swale below.
The ravine contains remnants of the former Adelaide Level lead mine, which is named after Lady Adelaide Lamont, a descendant of Judge Jeffreys. In 1865 a strike was made there, which yielded about £12,000 () worth of galena or lead ore. The mine closed in 1920. Miners worked in bad conditions in North Yorkshire lead mines during the Adelaide Level's era, with over 62% of local mines having extremely impure air. The most common occupational disease for miners was silicosis.
Description
Arn Gill is located in Swaledale, North Yorkshire, England, north of Muker and on the east side of the River Swale. It is a river-cut ravine or gully, containing a beck, also known as Arn Gill. The beck runs east–west in its gully, falling steeply downhill from its source on the fell Arn Gill Head, to its discharge point as a tributary of the River Swale.
Former lead mining
Lead mines in the Arn Gill area were worked between 1751 and 1921. However the Adelaide Level lead mine at Arn Gill near Muker was comparatively short-lived. This is the mine of which the remains are still visible.
George Cottingham's strike
Between Keldside and Kisdon are galena ore veins, and the south-eastern ends of these veins run below Arn Gill. Early attempts at mining this source were in 1811 and 1866 at West Arn Gill, which is to the north of Arn Gill, but "no ore was found". There had been drainage works in Arn Gill in the early nineteenth century, for other mines further up the hill. But when the deeper Adelaide Level was driven there, in 1865, a rich vein of ore was found by Sir George Denys' A.D. Company. Muker lead miner George Cottingham (c.1814–1876) and his son George (born c.1850) "hit a rich flat of ore" and according to historians Mike Gill and Edward Fawcett they were said to have thereby brought the company about £12,000 (). Thirty more tons of ore were found in Adelaide Level in 1918. However, by 1920 it was costing too much to pump out water, and the mine was abandoned. The Adelaide Level was named after Lady Adelaide Lamont of Knockdow, daughter of Sir George Denys, and descendant of Judge Jeffreys.
Working conditions
A gill (or ravine) like Arn Gill could facilitate lead mining where the ravine was already cut into the ore vein. That meant that a horizontal tunnel, or adit level, could be dug into the side of the ravine where ore was found. Some of these levels were named horse levels, because they were big enough for a small horse and cart.