2 indicate pain, discomfort, or displeasure; "The students groaned when the professor got out the exam booklets"; "The ancient door soughed when opened" [syn: groan, moan]
3 introduce into an environment; "sow suspicion or beliefs" [syn: sow]
EtymologyOld English swōgan, from Germanic *swoganan.
A Sough is an underground channel for draining water out of a mine. Its ability to drain a mine depends on the bottom of the mine being higher than a neighbouring valley. If the mine sump is lower, water must be pumped up to the sough.
Derbyshire Lead MiningThe term is closely associated with the lead mining areas of Derbyshire (see Derbyshire lead mining history).
Early Derbyshire lead mines were fairly shallow, since methods to remove water were inefficient and miners had to stop when they reached the water table. The digging of soughs was found to be an effective way of lowering the water table and allowing mines to be worked deeper.
Soughs were typically dug from their open end near a stream or river back into the hillside beneath the mine to be drained. One sough would often drain more than one mine, since these were often very close, working the same vein of lead. This also helped spread the cost of digging the sough. Some soughs include branches to facilitate further drainage.
Many soughs were dug throughout the 17th and 18th centuries, until the falling price of lead brought the decline of the Derbyshire lead mining industry towards the end of the 19th century.
Some soughs were very extensive. Meerbrook sough is over four miles in length. Digging such long tunnels took a long time. Vermuyden sough, named after the Dutch engineer Sir Cornelius Vermuyden who planned it, took twenty years to dig. The Cromford sough that Sir Richard Arkwright subsequently used to power his mill at Cromford took thirty years to dig, and was still being extended a century after it was begun.
Some soughs are still in use. According to the British Geological Survey, the Meerbrook sough, started in 1772, still provides 3.75 million litres a day for the public water supply.
ElsewhereSoughs were also extensively used in the coalmining industry until the mines became too deep to be drained by this means. With the advent of the steam engine, soughs became less necessary for unwatering mines than they had previously.
- Rosamunde Pilcher in Flowers in the Rain uses the descriptive term the "sough of the wind".
- Rieuwerts, J. H. History and gazetteer of the lead mine soughs of Derbyshire. Author, 1987