Opened 1846 by the Thompson family, sold 1888 to the Salt Union. The mine had two shafts and the workings covered an area of approximately 6 acres. Closed in the early 20th century and later used for the storage of explosives during and after the First World War, it was sealed in 1929 due to the excessive cost of pumping the mine dry. The site was mostly cleared although a section of large stonework remains, likely to be part of the canal dock.