Sough

A drainage tunnel driven to lower the water table in a mine, or an area of mines, by letting water run out under gravity rather than being pumped — the term used in this sense mainly in the Derbyshire lead orefield.

Historical usage

Derbyshire's lead mines were originally shallow, since early water-removal methods could not keep deeper workings dry; driving a sough to lower the water table let mining go deeper. The earliest recorded example, the Longhead Sough, was driven by the Dutch engineer Sir Cornelius Vermuyden between 1629 and 1636 to unwater the Dovegang mines at Cromford; sough-driving continued through the 17th, 18th and 19th centuries.

How it worked

A sough works on exactly the same gravity principle as a Cornish drainage adit: driven from a low point, such as a river valley, back into the hillside beneath the mine, it lets water drain out by itself rather than needing to be lifted mechanically. Because one sough could unwater several nearby mines working the same vein, the substantial cost of driving one was often shared between them.

Why it was used

A sough avoided the recurring cost of pumping, which before efficient steam power was a major and continuous expense; once driven, a sough drained a mine for free for as long as it remained clear, and let workings go deeper than water-removal by hand or horse power alone could ever have reached.

Risks & limitations

Soughs were expensive, slow, capital-intensive projects — the Hillcarr Sough, the largest in Derbyshire, ran four miles from the mines at Alport-by-Youlgreave to the River Derwent — and diverting a mine's water into a sough reduced the flow available to watermills and other users downstream, a frequent source of legal disputes over water rights between sough-builders and those who depended on the watercourses they fed from.

Regional variation

"Sough" is specifically the Derbyshire lead-mining term for this kind of gravity drainage tunnel; the same principle, under the name adit, is the term used in Cornwall and Devon.

Related terminology

Adit

Images

Mines associated with this term

Included only where MineArchive's own research gives a reasonable evidential basis — not every mine where this might plausibly apply.

• Magpie Mine — Derbyshire (well documented example)
  Magpie Sough, roughly 2km long and driven 1873-1881, was the last major sough driven in Derbyshire, built to unwater Magpie Mine into the River Wye.
• Mandale Mine — Derbyshire (well documented example)
  Mandale Sough is among the scheduled monument remains at Mandale and the wider Lathkill Dale mines.

Sources

1. (secondary) Sough — Wikipedia
2. (secondary) Soughs in Derbyshire mines — Derbyshire Heritage

Record created: 20 August 2026 · Last researched: 20 August 2026