Fire-setting is a method of
traditional mining used most commonly from
prehistoric times up to the
Middle Ages. Fires were set against a rock face to heat the
stone, which was then doused with liquid, causing the stone to fracture by
thermal shock. Some experiments have suggested that the water (or any other liquid) did not have a noticeable effect on the rock, but rather helped the miners' progress by quickly cooling down the area after the fire. This technique was best performed in
opencast mines where the smoke and fumes could dissipate safely. The technique was very dangerous in
underground workings without adequate ventilation. The method became largely redundant with the growth in use of
explosives.
Although fire-setting was frequently used before
modern times, it has been used sporadically since then. In some regions of the world, notably
Africa
Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...
and
Eurasia
Eurasia (, ) is the largest continental area on Earth, comprising all of Europe and Asia. Primarily in the Northern and Eastern Hemispheres, it spans from the British Isles and the Iberian Peninsula in the west to the Japanese archipelag ...
, fire-setting continued to be in use until the 19th and 20th centuries.
It was used where rock was too hard to drill holes with steel borers for blasting or whenever it was economic because of cheapness of wood.
History
The oldest traces of this method in Europe were found in southern
France
France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of overseas regions and territories in the Americas and the Atlantic, Pacific and Indian Oceans. Its metropolitan ar ...
(département of
Hérault
Hérault (; oc, Erau, ) is a department of the region of Occitania, Southern France. Named after the Hérault River, its prefecture is Montpellier. It had a population of 1,175,623 in 2019.[Copper Age
The Copper Age, also called the Chalcolithic (; from grc-gre, χαλκός ''khalkós'', "copper" and ''líthos'', "Rock (geology), stone") or (A)eneolithic (from Latin ''wikt:aeneus, aeneus'' "of copper"), is an list of archaeologi ...]
. Numerous finds exist from the
Bronze Age
The Bronze Age is a historic period, lasting approximately from 3300 BC to 1200 BC, characterized by the use of bronze, the presence of writing in some areas, and other early features of urban civilization. The Bronze Age is the second pri ...
, such as in the
Alps
The Alps () ; german: Alpen ; it, Alpi ; rm, Alps ; sl, Alpe . are the highest and most extensive mountain range system that lies entirely in Europe, stretching approximately across seven Alpine countries (from west to east): France, ...
, in the former mining district of
Schwaz
Schwaz () is a city in the Austrian state of Tyrol. It is the administrative center of the Schwaz district. Schwaz is located in the lower Inn valley.
Location
Schwaz lies in the middle of the Lower Inn Valley at the foot of the Kellerjoch a ...
-
Brixlegg in
Tyrol, or in the
Goleen area in
Cork,
[O’Brien, W: The Bronze Age copper mines of the Goleen area, Co Cork. Proc. R. Irish. Acad. 103, 2003:13–59] to name a few.
As for antique written sources, fire-setting is first described by
Diodorus Siculus
Diodorus Siculus, or Diodorus of Sicily ( grc-gre, Διόδωρος ; 1st century BC), was an ancient Greek historian. He is known for writing the monumental universal history '' Bibliotheca historica'', in forty books, fifteen of which ...
in his
Bibliotheca historica
''Bibliotheca historica'' ( grc, Βιβλιοθήκη Ἱστορική, ) is a work of universal history by Diodorus Siculus. It consisted of forty books, which were divided into three sections. The first six books are geographical in theme, a ...
written about 60 BC, about methods of mining used in
ancient Egyptian gold mines. It is also mentioned in greater detail by
Pliny the Elder
Gaius Plinius Secundus (AD 23/2479), called Pliny the Elder (), was a Roman author, naturalist and natural philosopher, and naval and army commander of the early Roman Empire, and a friend of the emperor Vespasian. He wrote the encyclopedic ...
in his
Naturalis Historia, published in the first century AD. In Book XXXIII, he describes mining methods for
gold
Gold is a chemical element with the symbol Au (from la, aurum) and atomic number 79. This makes it one of the higher atomic number elements that occur naturally. It is a bright, slightly orange-yellow, dense, soft, malleable, and ductile ...
, and the pursuit of the gold-bearing veins underground using tunnels and
stopes. He mentions the use of
vinegar
Vinegar is an aqueous solution of acetic acid and trace compounds that may include flavorings. Vinegar typically contains 5–8% acetic acid by volume. Usually, the acetic acid is produced by a double fermentation, converting simple sugars to ...
to quench the hot rock, but water would have been just as effective, as vinegar was expensive at the time for regular use in a mine. The reference to vinegar may come from a description by
Livy
Titus Livius (; 59 BC – AD 17), known in English as Livy ( ), was a Roman historian. He wrote a monumental history of Rome and the Roman people, titled , covering the period from the earliest legends of Rome before the traditional founding in ...
of
Hannibal
Hannibal (; xpu, 𐤇𐤍𐤁𐤏𐤋, ''Ḥannibaʿl''; 247 – between 183 and 181 BC) was a Carthaginian general and statesman who commanded the forces of Carthage in their battle against the Roman Republic during the Second Pu ...
's crossing of the
Alps
The Alps () ; german: Alpen ; it, Alpi ; rm, Alps ; sl, Alpe . are the highest and most extensive mountain range system that lies entirely in Europe, stretching approximately across seven Alpine countries (from west to east): France, ...
, when it was said that the soldiers used vinegar in fire-setting to remove large rocks in the path of his army. The effectiveness of strong
acetic acid
Acetic acid , systematically named ethanoic acid , is an acidic, colourless liquid and organic compound with the chemical formula (also written as , , or ). Vinegar is at least 4% acetic acid by volume, making acetic acid the main componen ...
solutions on heated limestone has been demonstrated in laboratory experiments.
Pliny also says that the method was used both in opencast and deep mining. This is confirmed by remains found at the Roman
gold mine Gold Mine may refer to:
* Gold Mine (board game)
*Gold Mine (Long Beach), an arena
*"Gold Mine", a song by Joyner Lucas from the 2020 album ''ADHD''
See also
* ''Gold'' (1974 film), based on the novel ''Gold Mine'' by Wilbur Smith
* Gold mining
*G ...
of
Dolaucothi in west
Wales
Wales ( cy, Cymru ) is a Countries of the United Kingdom, country that is part of the United Kingdom. It is bordered by England to the Wales–England border, east, the Irish Sea to the north and west, the Celtic Sea to the south west and the ...
, when modern miners broke into much older workings during the 1930s where they found wood ashes near worked rock faces. In another part of the mine, there are three
adits at different heights which have been driven through barren rock to the gold-bearing veins for some considerable distance, and they would have provided drainage as well as ventilation to remove the smoke and hot gases during a fire-setting operation. They were certainly much larger in section than was normal for access galleries, and the draught of air through them would have been considerable.
Fire-setting was used extensively during opencast mining, and is also described by Pliny in connection with the use of another mining technique known as
hushing
Hushing is an ancient and historic mining method using a flood or torrent of water to reveal mineral veins. The method was applied in several ways, both in prospecting for ores, and for their exploitation. Mineral veins are often hidden below ...
.
Aqueducts were built to supply copious amounts of water to the minehead, where they were used to fill tanks and
cistern
A cistern (Middle English ', from Latin ', from ', "box", from Greek ', "basket") is a waterproof receptacle for holding liquids, usually water. Cisterns are often built to catch and store rainwater. Cisterns are distinguished from wells by ...
s. The water was unleashed to scour the hillside below, both soil in the case of prospecting for metal veins, and then rock debris after a vein had been found. Fire-setting was used to break up the hard rocks of the vein and the surrounding barren rock, and was much safer to use in above ground workings since the smoke and fumes could dissipate more easily than in a confined space underground. Pliny also describes undermining methods that were used to facilitate the removal of hard rocks, and probably softer alluvial deposits as well.
Medieval Europe
The method continued in use in the medieval period, and is described by
Georg Agricola in his treatise on mining and mineral extraction,
De re metallica. He warns about the problem of the "foetid vapours" and the need to evacuate the workings while the fires are lit, and presumably for some time afterwards until the gases and smoke had cleared. The problem raises the question of ventilation means in the mines, a problem often solved by ensuring that there was a continuous path for escape of the noxious fumes, perhaps aided by artificial ventilation. Agricola mentions the use of large water-powered
bellows to create a draught, and continuity of workings to the surface were essential for a stream of air to run through them.
In later times, a fire at the base of a shaft was used to create an updraught, but just like fire-setting, it was a hazardous and dangerous procedure, especially in
collieries. As the number and complexity of the underground workings increased, care was needed to channel the air draught to all parts of the tunnels and faces. It was usually achieved by installing doors at key points. Most of the deaths in coal
mine disaster
A mining accident is an accident that occurs during the process of mining minerals or metals. Thousands of miners die from mining accidents each year, especially from underground coal mining, although accidents also occur in hard rock mining. C ...
s were caused by inhalation of the toxic gases produced by
firedamp explosions.
The method continued in use for many years afterwards until finally made redundant by the use of
explosives. However, they also produce toxic gases and care is needed to ensure good ventilation to remove those gases, like
carbon monoxide
Carbon monoxide ( chemical formula CO) is a colorless, poisonous, odorless, tasteless, flammable gas that is slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the si ...
, as well as choice of the explosive itself to minimise their emission.
See also
*
Derbyshire lead mining history
References
Further reading
*Healy, JF, ''Pliny the Elder on Science and Technology'', Clarendon Press (1999).
*Oliver Davies, ''Roman Mines in Europe'', Clarendon Press (Oxford), (1935).
*Lewis, P. R. and G. D. B. Jones, ''The Dolaucothi gold mines, I: the surface evidence'', The Antiquaries Journal, 49, no. 2 (1969): 244-72.
External links
Fire-setting at Alderley edge copper mines(broken_link)
Fire-setting in ancient Indian mines(broken_link)
*
*
{{DEFAULTSORT:Fire-Setting
Traditional mining
History of mining