Ammonal is an explosive made up of ammonium nitrate, trinitrotoluene (TNT), and aluminium
Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....


The ammonium nitrate functions as an oxidizer and aluminium as a power enhancer. To some extent the aluminium makes it more sensitive to detonation. The use of the relatively cheap ammonium nitrate and aluminium makes it a replacement for pure TNT.

The mixture can suffer humidity because ammonium nitrate is highly hygroscopic
Hygroscopy is the ability of a substance to attract and hold water molecules from the surrounding environment. This is achieved through either absorption or adsorption with the absorbing or adsorbing material becoming physically 'changed,' somewhat, by an increase in volume, stickiness, or other...

. Ammonal burns vigorously when open to the air, but detonates when confined inside some form of casing.

The detonation velocity of ammonal is approximately 4,400 metres per second or 9,842 miles per hour.


From early 1916 the British Army
British Army
The British Army is the land warfare branch of Her Majesty's Armed Forces in the United Kingdom. It came into being with the unification of the Kingdom of England and Scotland into the Kingdom of Great Britain in 1707. The new British Army incorporated Regiments that had already existed in England...

 employed ammonal for their mines during World War I
World War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...

, starting with the Hawthorn Ridge mine during the Battle of the Somme. Three of the mines used at the Battle of Messines
Battle of Messines
The Battle of Messines was a battle of the Western front of the First World War. 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...

 which were exploded at the start of the Third Battle of Ypres contained 30,000 lbs (over 13.6 metric tons) of ammonal, a fourth contained 20,000 lbs (over 9 metric tons). 1917 – World War I: The British Army detonated 19 ammonal mines under the German lines, killing 10,000 in the deadliest non-nuclear man-made explosion in history. Ammonal used for military mining purposes was generally contained within metal cans or rubberised bags to prevent moisture ingress problems.

Not all of the mines that had been laid at Messines were detonated. Two of the original 21 mines were not ignited because they were outside the area of the offensive. On 17 July 1955, a lightning strike set off one of the remaining mines. There were no human casualties, but one cow was killed. The 21st mine is believed to have been found, but no attempt has been made to remove it. It is possible that the one unexploded mine was dismantled, because German tunnellers were coming too close to the chamber.

Ammonal remains in use as an industrial explosive. Typically, it is used for quarry
A quarry is a type of open-pit mine from which rock or minerals are extracted. Quarries are generally used for extracting building materials, such as dimension stone, construction aggregate, riprap, sand, and gravel. They are often collocated with concrete and asphalt plants due to the requirement...

ing or mining
Mining is the extraction of valuable minerals or other geological materials from the earth, from an ore body, vein or seam. The term also includes the removal of soil. Materials recovered by mining include base metals, precious metals, iron, uranium, coal, diamonds, limestone, oil shale, rock...



An ammonal mixture previously used in hand grenade
Hand grenade
A hand grenade is any small bomb that can be thrown by hand. Hand grenades are classified into three categories, explosive grenades, chemical and gas grenades. Explosive grenades are the most commonly used in modern warfare, and are designed to detonate after impact or after a set amount of time...

s and shells
Shell (projectile)
A shell is a payload-carrying projectile, which, as opposed to shot, contains an explosive or other filling, though modern usage sometimes includes large solid projectiles properly termed shot . Solid shot may contain a pyrotechnic compound if a tracer or spotting charge is used...

has the proportions (by mass):
  • ammonium nitrate 58.6%
  • aluminum powder 21%
  • charcoal 2.4%
  • trinitrotoluene 18%
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