
Q-pits are kiln sites which were dug for the production of
white coal
White coal is a form of fuel produced by drying chopped wood over a fire. It differs from charcoal which is carbonised wood. White coal was used in England to melt lead ore from the mid-sixteenth to the late seventeenth centuries. It produces more ...
prior to the
Industrial Revolution
The Industrial Revolution, sometimes divided into the First Industrial Revolution and Second Industrial Revolution, was a transitional period of the global economy toward more widespread, efficient and stable manufacturing processes, succee ...
when white coal was largely superseded by the use of
coke.
Purpose
The white coal produced in Q-pits was largely used in the
smelting
Smelting is a process of applying heat and a chemical reducing agent to an ore to extract a desired base metal product. It is a form of extractive metallurgy that is used to obtain many metals such as iron-making, iron, copper extraction, copper ...
of
lead
Lead () is a chemical element; it has Chemical symbol, symbol Pb (from Latin ) and atomic number 82. It is a Heavy metal (elements), heavy metal that is density, denser than most common materials. Lead is Mohs scale, soft and Ductility, malleabl ...
from about 1550 to 1750, when a process was discovered that used coal. The large sections of white coal had previously been mixed with
charcoal
Charcoal is a lightweight black carbon residue produced by strongly heating wood (or other animal and plant materials) in minimal oxygen to remove all water and volatile constituents. In the traditional version of this pyrolysis process, ca ...
to give the right temperature, as charcoal alone was too hot and would have
volatilised the lead.
[ Rackham, Oliver (2007). ''The New Naturalist Series. Woodlands''. London: Collins. . p. 205.] Some evidence exists to suggest that some had a secondary use in the charking of coal into coke.
Location
Many Q-pits were located in
deciduous
In the fields of horticulture and botany, the term deciduous () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed Leaf, leaves, usually in the autumn; to the shedding of petals, aft ...
woodlands and as such they are an important landscape feature indicating both previous industrial activity and the presence of a
woodland
A woodland () is, in the broad sense, land covered with woody plants (trees and shrubs), or in a narrow sense, synonymous with wood (or in the U.S., the '' plurale tantum'' woods), a low-density forest forming open habitats with plenty of sunli ...
at the site or nearby.
[Muir, Richard (2008). ''Woods, Hedgerows and Leafy Lanes.'' Pub. Tempus, Stroud. . pp. 91 - 92.] The pits are often found in association with
saw pit
A saw pit or sawpit is a pit over which timber is positioned to be sawed with a long two-handled saw, usually a whipsaw, by two people, one standing above the timber and the other below. It was used for producing sawn planks from tree trunks, ...
s.
Construction
The pits were created by removing soil to create a depression about 12–13 feet (4m) in diameter, breached by a 'spout' and thus forming a 'Q' shape. The pits were dug from the end of the
Middle Ages
In the history of Europe, the Middle Ages or medieval period lasted approximately from the 5th to the late 15th centuries, similarly to the post-classical period of global history. It began with the fall of the Western Roman Empire and ...
up to around 1760, the start of the Industrial Revolution.
[Muir, Richard (2008). ''Woods, Hedgerows and Leafy Lanes.'' Pub. Tempus, Stroud. . p. 92.] Potash pits were of a similar shape and size, however, they were used to make
potash
Potash ( ) includes various mined and manufactured salts that contain potassium in water- soluble form. for use in coursing or degreasing wool and were once found in sheep rearing areas.
Geographical location
The pits are a common feature in lead mining districts such as the
Leadhills
Leadhills, originally settled for the accommodation of miners, is a village in South Lanarkshire, Scotland, WSW of Elvanfoot. The population in 1901 was 835. It was originally known as Waterhead.
It is the second highest village in Scotland, ...
in Scotland and East Derbyshire.
Due to their small size, they are not likely to be confused with quarries, although bomb craters from
World War II
World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...
can occasionally lead the landscape historian astray.
In 2007 an isolated example was identified and excavated in
Westbury-sub-Mendip
Westbury-sub-Mendip is a village and civil parish in Somerset, England. The village is on the southern slopes of the Mendip Hills, from Wells and Cheddar.
The parish boundary is formed by the River Axe.
History
There is evidence, from fl ...
near the lead smelting areas on the
Mendip Hills
The Mendip Hills (commonly called the Mendips) is a range of limestone hills to the south of Bristol and Bath, Somerset, Bath in Somerset, England. Running from Weston-super-Mare and the Bristol Channel in the west to the River Frome, Somerset ...
in Somerset.
Over 200 such pits have been surveyed in
Ecclesall Woods, Sheffield.
References
{{Reflist
Buildings and structures in Scotland
Buildings and structures in England
Archaeological sites in Scotland
Archaeological sites in England
Timber industry
Lead mining in the United Kingdom
History of forestry
Forestry in the United Kingdom