Mining,
undermining, or
sapping was a
siegeA siege is a military blockade of a city or fortress with the intent of conquering by attrition or assault. The term derives from sedere, Latin for "to sit"....
method used since
antiquityClassical antiquity is a broad term for a long period of cultural history centered on the Mediterranean Sea, comprising the interlocking civilizations of Ancient Greece and Ancient Rome collectively known as the Greco-Roman world...
against a walled city, fortress or
castleA castle is a defensive structure seen as one of the main symbols of the Middle Ages. The term has a history of scholarly debate surrounding its exact meaning, but it is usually regarded as being distinct from the general terms fort or fortress, in that it describes a residence of a monarch or...
.
Use in antiquity
The Greek historian
PolybiusPolybius was a Greek historian of the Hellenistic Period noted for his book called The Histories covering in detail the period of 220–146 BC...
, in his
HistoriesPolybius’ The Histories were originally written in 40 volumes, only the first five of which are extant in their entirety. The bulk of the work, except for the 40th volume, which was the index volume, is passed down to us through collections of excerpts kept in libraries in Byzantium, for the most...
, gives a graphic account of mining and counter mining at the Roman siege of
AmbraciaAmbracia, occasionally Ampracia , was an ancient Corinthian colony, situated about 7 miles from the Ambracian Gulf in Greece, on a bend of the navigable river Arachthos , in the midst of a fertile wooded plain....
:
- The Aetolians [...] offered a gallant resistance to the assault of the siege artillery and [the Romans], therefore, in despair had recourse to mines and underground tunnels. Having safely secured the central one of their three works, and carefully concealed the shaft with wattle screens, they erected in front of it a covered walk or stoa about two hundred feet long, parallel with the wall; and beginning digging from that, they carried it on unceasingly day and night, working in relays. For a considerable number of days the besieged did not discover them carrying the earth away through the shaft; but when the heap of earth thus brought out became too high to be concealed from those inside the city, the commanders of the besieged garrison set to work vigorously digging a trench inside, parallel to the wall and to the stoa which faced the towers. When the trench was made to the required depth, they next placed in a row along the side of the trench nearest the wall a number of brazen vessels made very thin; and, as they walked along the bottom of the trench past these, they listened for the noise of the digging outside. Having marked the spot indicated by any of these brazen vessels, which were extraordinarily sensitive and vibrated to the sound outside, they began digging from within, at right angles to the trench, another underground tunnel leading under the wall, so calculated as to exactly hit the enemy's tunnel. This was soon accomplished, for the Romans had not only brought their mine up to the wall, but had under-pinned a considerable length of it on either side of their mine; and thus the two parties found themselves face to face. [Plb.+21.28]
According to Polybius, this was the first time poison gas was used.[POLYBIOS 21.28]
Another extraordinary usage of siege-mining in the ancient greece, where during Philip V of Macedon's siege of the little town of Prinassos, according to Polybius,"the ground around the town were extremely rocky and hard, making any siege-mining virtually impossible. However, Philip ordered his soldiers during the cover of night collect earth from elsewhere and throw it all down at the fake tunnel's entrance, making it look like the macedonians were almost finished completing the tunnels!
Eventually, when Philip V announced that large parts of the town-walls were undermined the citizens surrendered without delay." [POLYBIOS 16.11]
Mining was a siege method used in ancient China from at least the Warring States (481–221 BC) period forward. When enemies attempted to dig tunnels under walls for mining or entry into the city, the defenders used large
bellowsA bellows is a device for delivering pressurized air in a controlled quantity to a controlled location. Basically, a bellows is a deformable container which has an outlet nozzle. When the volume of the bellows is decreased, the air escapes through the outlet...
(the type the Chinese commonly used in heating up the
blast furnaceA blast furnace is a type of metallurgical furnace used for smelting to produce industrial metals, generally iron.In a blast furnace, fuel and ore are continuously supplied through the top of the furnace, while air is blown into the bottom of the chamber, so that the chemical reactions take place...
for smelting
cast ironCast iron usually refers to grey iron, but also identifies a large group of ferrous alloys, which solidify with a eutectic. The colour of a fractured surface can be used to identify an alloy. White cast iron is named after its white surface when fractured, due to its carbide impurities which...
) to pump smoke into the tunnels in order to suffocate the intruders.
Use in the Middle Ages
In warfare during the
Middle AgesThe Middle Ages of European history is a period of European history covering roughly a millennium in the 5th century through 16th centuries. More specific starting and ending points are sometimes adopted by scholars to suit their respective specializations or current focus...
, a "mine" was a tunnel dug to bring down castles and other
fortificationFortifications are military constructions and buildings designed for defense in warfare and military bases. Humans have constructed defensive works for many thousands of years, in a variety of increasingly complex designs...
s. The technique was used when the fortification was not built on solid rock, and was developed as a response to
stoneIn geology, rock is a naturally occurring solid aggregate of minerals and/or mineraloids.The Earth's outer solid layer, the lithosphere, is made of rock. In general rocks are of three types, namely, igneous, sedimentary, and metamorphic...
built castles that could not be burned like earlier-style wooden forts. A
tunnelA tunnel is an underground passageway. The definition of what constitutes a tunnel is not universally agreed upon. However, in general tunnels are at least twice as long as they are wide. In addition, they should be completely enclosed on all sides, save for the openings at each end...
would be excavated under the outer defenses either to provide access into the fortification or to collapse the walls. These tunnels would normally be supported by temporary wooden props as the digging progressed. Once the excavation was complete, the wall or tower being undermined would be collapsed by filling the excavation with combustible material that, when lit, would burn away the props leaving the structure above unsupported and thus liable to collapse. Later, explosives were used for greater effect.
A tactic related to mining is sapping the wall, where engineers would dig at the base of a wall with crowbars and picks. Peter of les Vaux-de-Cernay recounts how at the battle of
CarcassonneCarcassonne is a fortified French town in the Aude département, of which it is the prefecture, in the former province of Languedoc.It is separated into the fortified Cité de Carcassonne and the more expansive lower city, the ville basse...
, during the
Albigensian CrusadeThe Albigensian Crusade or Cathar Crusade was a 20-year military campaign initiated by the Catholic Church to eliminate the Cathar heresy in Languedoc...
, "after the top of the wall had been somewhat weakened by bombardment from
petrariesA siege engine is a device that is designed to break or circumvent city walls and other fortifications in siege warfare. Some have been operated close to the fortifications, while others have been used to attack from a distance. From antiquity, siege engines were constructed largely of wood and...
, our engineers succeeded with great difficulty in bringing a four-wheeled wagon, covered in oxhides, close to the wall, from which they set to work to sap the wall" (les Vaux-de-Cernay, 53).
As in the siege of Carcassonne, defenders worked to prevent sapping by dumping anything they had down on attackers who tried to dig under the wall. Successful sapping usually ended the battle since either the defenders would no longer be able to defend and surrender, or the attackers would simply charge in and engage the defenders in close combat.
There were several methods to resist under mining. Often the siting of a castle could be such as to make mining difficult. The walls of a castle could be constructed either on solid rock or on sandy or water logged land making it difficult to dig mines. A very deep ditch or moat could be constructed in front of the walls, as was done at
Pembroke CastlePembroke Castle is a medieval castle in Pembroke, West Wales.The first castle was established in 1093 during the Norman invasion of Wales. However its present appearance owes much to William Marshal, one of the most powerful men in 12th-Century Britain....
, or even artificial lakes as was done at
Kenilworth CastleKenilworth Castle is a castle located in Kenilworth, Warwickshire, England . Historically the Castle was contained within the Forest of Arden....
. This makes it more difficult to dig a mine and even if a breach is made the ditch or moat makes exploiting the breach difficult. The defenders could also dig counter mines. From these they could then either dig into the attackers tunnels and
sortieSortie is a term for deployment or dispatch of one military unit, be it an aircraft, ship, or troops from a strongpoint. The sortie, whether by one or more aircraft or vessels, usually has a specific mission....
into them to either kill the miners or to set fire to the pit-props to collapse the attackers tunnel. Alternatively they could under mine the attackers tunnels and create a
camoufletA camouflet, in military science, is an artificial cavern created by an explosion to undermine a structure. If the explosion reaches the surface then it is called a crater....
to collapse the attacker's tunnels. Finally if the walls were breached they could either place obstacles in the breach for example a chevaux de frise to hinder a
forlorn hopeA forlorn hope is a band of soldiers or other combatants chosen to take the leading part in a military operation, such as an assault on a defended position, where the risk of casualties is high. The term comes from the Dutch verloren hoop, literally "lost heap", and adapted as "lost troop"...
, or construct a
coupureDuring a siege a Coupure is a ditch or an earthenwork or wooden palisade built behind a breach in the walls of a fortress, or a city, made by the attacker's guns...
. The great concentric ringed fortresses like
Beaumaris CastleBeaumaris Castle, located in Beaumaris, Anglesey, Wales was built as part of King Edward I's campaign to conquer the north of Wales. It was designed by James of St. George and was begun in 1295, but never completed...
on
AngleseyThe Isle of Anglesey , is an island and county off the northwest coast of Wales, with a predominantly Welsh-speaking population. It is connected to the mainland by two bridges spanning the Menai Strait: the original Menai Suspension Bridge , designed by Thomas Telford in 1826; and the newer...
were designed in such a way that the inner walls were ready built coupures so that if an attacker succeeded in breaching the outer walls would have left them in a
killing fieldA killing field, in military science, is an area in front of a defensive position that the enemy must cross during an assault and is specifically intended to allow the defending troops to incapacitate a large number of the enemy. Defensive emplacements such as anti-tank obstacles, barbed wire and...
between the lower outer walls and the higher inner walls.
Use in the American Civil WarThe American Civil War , also known as the War Between the States and several other names, was a civil war in the United States of America. Eleven Southern slave states declared their secession from the United States and formed the Confederate States of America...
During the Siege of Vicksburg in 1863 Union troops led by General
Ulysses S. GrantUlysses S. Grant was general-in-chief of the Union Army from 1864 to 1869 during the American Civil War and the 18th President of the United States from 1869 to 1877....
tunnelled under the Confederate trenches and detonated the mine beneath the 3rd Louisiana Redan on June 25, 1863. The following assault led by General
John A. LoganJohn Alexander Logan was an American soldier and political leader. He served in the Mexican-American War and was a General in the Union Army in the American Civil War. He served the state of Illinois as a Senator and was an unsuccessful candidate for Vice President of the United States.-Early life...
gained a foothold in the Confederate trenches where the crater was formed but the attackers were eventually forced to withdraw.
A more famous instance occurred during the
Siege of PetersburgThe Richmond–Petersburg Campaign was a series of battles around Petersburg, Virginia, fought from June 9, 1864, to March 25, 1865, during the American Civil War...
, Union troops dug a tunnel under the
ConfederateThe Confederate States of America was a separatist political entity existing between 1861 to 1865, established by eleven southern slave states of the United States of America, each of which had previously declared their secession from the United States...
lines at Elliott's Salient and packed its end with vast amounts of gunpowder. When set off, the resulting explosion killed about 300 soldiers. It might have been decisive if not for the faulty Union tactic of storming into, rather than around, the resulting crater, allowing the defenders to shoot down onto attackers unable to climb the steep crater sides. The combat was accordingly known as the
Battle of the CraterThe Battle of the Crater was a battle of the American Civil War, part of the Siege of Petersburg. It took place on July 30, 1864, between the Confederate Army of Northern Virginia, commanded by General Robert E. Lee and the Union Army of the Potomac, commanded by Maj. Gen. George G. Meade The...
. (The horror of this engagement was portrayed in the Charles Frazier novel and subsequent
Anthony MinghellaAnthony Minghella, CBE was an English film director, playwright and screenwriter. He was Chairman of the Board of Governors at the British Film Institute between 2003 and 2007.-Early life:...
movie
Cold MountainCold Mountain is a 2003 film written and directed by Anthony Minghella. The film is based on the novel by Charles Frazier.- Plot :The movie opens depicting the events leading up to the American Civil War, and proceeds to a vivid recreation of the Battle of the Crater. Jude Law plays a Confederate...
.)
Use in modern warfare
Mining saw a brief resurgence as a military tactic during the
First World WarWorld War I , also known as the First World War, the Great War, and the War to End All Wars, was a global military conflict which involved most of the world's great powers, assembled in two opposing alliances: the Triple Entente and the Triple Alliance...
when army engineers would attempt to break the stalemate of
trench warfareTrench warfare was a form of warfare in which both combatants occupied static fortified fighting lines, consisting largely of trenches, in which troops were largely immune to the enemy's small arms fire and were substantially sheltered from artillery. It has become a byword for stalemate in...
by tunneling under
no man's landNo man's land is a term for land that is not occupied or more specifically land that is under dispute between countries or areas that will not occupy it because of fear or uncertainty...
and laying large quantities of explosives beneath the enemy's trench. As in siege warfare, mining was possible due to the static nature of the fighting.
A notable example was the
Battle of MessinesThe Battle of Messines was a battle of the western front of World War I. It began on 7 June 1917 when the British Second Army under the command of General Herbert Plumer launched an offensive near the village of Mesen in West Flanders, Belgium...
, when 450 tonnes of high explosive were placed in 21 mines after about two years of sapping. Approximately 10,000
GermanGermany , officially the Federal Republic of Germany , is a country in Central Europe. It is bordered to the north by the North Sea, Denmark, and the Baltic Sea; to the east by Poland and the Czech Republic; to the south by Austria and Switzerland; and to the west by France, Luxembourg, Belgium,...
troops were killed when 19 of the mines were simultaneously detonated. One of the explosive caches exploded years later. The 21st cache was never found and there are still several tonnes of high explosive buried somewhere in the
BelgianThe Kingdom of Belgium is a country in northwest Europe. It is a founding member of the European Union and hosts its headquarters, as well as those of other major international organizations, including NATO...
countryside.
Another example is recorded in Louis Trenker's Berge in Flammen. Whole mountain peaks at the
AlpsThe Alps are one of the great mountain range systems of Europe, stretching from Austria and Slovenia in the east; through Italy, Switzerland, Liechtenstein and Germany; to France in the west....
were exploded during the mountain war.
Col di LanaThe Col di Lana is a mountain of the Fanes Group in the Italian Dolomites, situated in Livinallongo del Col di Lana , a municipality of the Province of Belluno, in the Italian region of Veneto....
, Lagazuoi and Marmolata, were a few of these peaks.
Because
World War IIWorld War II, or the Second World War , was a global military conflict which involved a majority of the world's nations, including all great powers, organized into two opposing military alliances: the Allies and the Axis...
troop movements were too fluid, and tunneling too slow, mining proved not to be worth the investment of effort.
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