The Seathwaite Plumbago Mine

Plumbago Mine, Bartholemews One Inch map 1920

The Seathwaite mine in Cumberland was once the world’s leading supplier of ‘black lead’

Graphite, also known as Plumbago or Black Lead is a rare pure form of carbon. Known as ‘wad’ it had long been used locally in Cumberland for marking sheep, but in the 16th century its industrial potential was realised, especially in making moulds for casting cannon balls. Its potential for replacing dry-point or metal point for writing and drawing was also realised, and the earliest reference to using graphite in what we would now call pencils dates from 1565.

Around that time too, Laurence Nowell, of Whalley, Lancashire, who had made maps for Queen Elizabeth’s chief Minister William Cecil, visited the county, and may have acquired some graphite, because he used it on a map he made c.1565-6, now in the British Library (Cotton Domitian A XVIII) (see chapter 6 in Exploring Antiquities and Archaeology in the North-West )

In the 17th century, the mine was only worked for short periods, in order to keep supplies short and hence prices high – but the Borrowdale mines nevertheless became the world’s leading supplier. Eventually, the seams ran out, and the mines closed in the 19th century. The site is now listed. The Derwent Pencil Museum in Keswick tells the story