Tunnelling companies of the Royal Engineers

The Royal Engineer tunnelling companies were a specialist unit of the Corps of Royal Engineers with the British Army, formed to mine attacking tunnels under enemy lines during the First World War.

After the first German attacks on December 21, 1914, through shallow tunnels across No Man’s Land, exploding ten mines under the trenches of the Indian Sirhind Brigade, the British began forming suitable tunnelling companies. In February 1915, eight Tunnelling Companies were created, operational in Flanders from March 1915. By mid-1916, the British Army had around 25,000 trained tunnellers, mostly taken the coal mining communities of South Wales, and the Northeast of England covering Nottinghamshire, Derbyshire and Yorkshire. Almost twice that number of "attached infantry" worked permanently alongside the trained miners acting as beasts of burden.

Background

Main article: Mining (military)

In siege warfare, tunnelling is along held tactic for breaching and breaking the enemies. From the Greek historian Polybius, in his Histories, gave accounts of mining during Philip V of Macedon's siege of the little town of Prinassos, and a graphic account of mining and counter mining at the Roman siege of Ambracia.

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 bellows (the type the Chinese commonly used in heating up the blast furnace for smelting cast iron) to pump smoke into the tunnels in order to suffocate the intruders.

WW1 Trench warfare

By the end of May 1915, a continuous opposed pair of defence-in-depth trench earthworks with no vulnerable flanks, stretched from the North Sea coast to neutral Switzerland. With both sides equally well dug-in and deploying comparable troop numbers and armaments, neither was to prove strong enough to force a decisive breakthrough.

The resultant siege meant that tunnelling saw a brief resurgence as a military tactic during the First World War. As in siege warfare, mining was possible due to the static nature of the fighting. Secondly, as the ground was mineable everywhere, the Western Front was a prime candidate for underground warfare.

The first deployment of military mining was by the Germans on December 21, 1914, through shallow tunnels across No Man’s Land, exploding ten mines under the trenches of the Indian Sirhind Brigade.

Formation of units

In February 1915, eight tunnelling companies were created, to fulfil a requirement to break through the German armies defensive positions by mining under the enemy trenches. The companies were mostly made of men drawn from the ranks of the infantry, mixed with men specifically drafted for this kind of work.

This was one of the most rapid acts of the First World War in which men who were working underground as civilians in Great Britain on February 17 1915 were working underground on the Western Front a mere four days later. This action showed the importance of the necessity for a counter-offensive against the aggressive German mining against the British lines. Twelve Tunnelling Companies were ultimately formed in 1915, and one additional one in 1916. A Canadian, three Australian and one New Zealand tunnelling companies were formed by March 1916. All of these companies were occupied on underground work together with the digging of subways, saps (a narrow trench dug to approach enemy trenches), cable trenches, underground chambers, for such things as signals and medical services, as well as offensive and defensive mining.

Methodology

Both sides deployed tunnelling, with the German lead quickly followed by British follow-up. The result was a labyrinth of tunnels within a cat and mouse game of tunnelling, and counter tunnelling and counter tactics. As the tactics and counter tactics deployed against each other became less and less effective, the depth at which the tunnels needed to be dug got deeper and deeper, and hence more dangerous. The result was a greater time to dig, resulting in both a greater vulnerability to both leakage of information and tunnel collapse, and a higher loss of lives in the most hideous of circumstances: entombment, drowning, gassing or obliteration in cramped and claustrophobic galleries beneath no man’s land.

To make the tunnels safer and quicker to deploy, the British Army enlisted experienced coal miners, many often outside their nominal recruitment policy. Upon the declaration of war in April 1914, William Hackett VC applied and was turned down three times at the age of 41 by the York and Lancaster Regiment. The desperate need for skilled miners saw notices requesting volunteer tunnellers posted in collieries, mineral mines and quarries. On October 25, 1915, despite having been being diagnosed with a heart condition, Hackett was enlisted and sent for two weeks basic training at Chatham, joining the 172 Tunnelling Company.

Counter tactics

Listening

During tunnelling operations, in side shafts were deployed listening post manned by men who's job was to listen for signs of enemy tunnelling. Initially using just manual methods, the British were eventually equipped with Geophone, which could detect noises up to 50 metres (160 ft) away. Employing two Geophones a listener was able to ascertain the direction of hostile activity by moving the sensors until sound levels appeared equal in both ears. A compass bearing was then taken. When gauging distance only, both earpieces were plugged into a single sensor; this was a skill only gained by experience.

Eventually deploying listeners in different tunnels in triangulation technics, by the end of 1916 the scale of British mine warfare had expanded to such an extent that there were not enough listeners to man every post, and central listening stations were devised. Working electronically like a telephone exchange, the signals from up to 36 remote sensors (Tele-geophones and Seismomicrophones) could be distinguished and recorded by just two men.

Underground mines

The tunnellers developed counter tactics, which both sides deployed. The first was the use of large minces placed in your own tunnels - some actually dug towards enemy noise to create damage - which when exploded would create fissures and cracks within the ground, making the ground either unsuitable to tunnel through or destroying existing tunnels and works. A smaller device, called the camouflet, created a localised underground blasts designed not to break the surface and form craters, but to destroy a strictly limited area of underground territory – and its occupants.

The second tactic, deployed when the enemy tunnel was too close to your existing works or trenches, was the deployment of rod-fed torpedo shaped camouflets. Effectively land mines on the end of long iron sticks, the technique was a defensive tactic against immediate threat. Towards the end of the tunnel war, forces also deployed mine fields at greater depths, which together with listening devices could be exploded away from your own trenches as a defensive measure.

Operations

Explosion of the mine beneath Hawthorn Ridge Redoubt, July 1 1916. Photo by Ernest Brooks.

Mines through the war became larger and larger.

Battle of Messines

Main article: Battle of Messines

In January, 1917, General Sir Herbert Plumer, gave orders for 21 mines to be placed under German lines during the Battle of Messines.

Over a period beginning more than a year before the attack, Canadian, Australian, New Zealand and British engineers tunnelled under the German trenches, laying 21 mines totalling 455 tonnes of ammonal explosive. To solve the problem of wet soil, the tunnels were made in the layer of "blue clay", 80–120 feet (25–30 m) below the surface. The galleries dug in order to lay these mines totalled over 8,000 yards (7,300 m) in length, and had been constructed in the face of tenacious German counter-mining efforts. On several occasions, German tunnellers were within metres of large British mine "chambers". One mine was found by the Germans, and the chamber was wrecked by a countermine.

The evening before the attack, General Plumer remarked to his staff, "Gentlemen, we may not make history tomorrow, but we shall certainly change the geography."

"Lone Tree Crater" in November 2009

Simultaneous explosion of the mines took place at 03:10 on June 7th. Aproximately 10,000 German troops were killed when 19 of the mines were simultaneously detonated, creating an explosion so loud it was heard in London. The largest of the 21 Messines mines was at Spanbroekmolen; the "Lone Tree Crater" formed by the blast was approximately 250 feet (76 m) in diameter, and 40 feet (12 m) deep. The mine consisted of 41 tons of ammonal explosive, located in a chamber dug 88 feet (27 m) below ground.

One of the remaining explosive caches exploded years later. The 21st cache was never found, and there are still several tonnes of high explosive buried somewhere in the Belgian countryside.

Other operations

Another example is recorded in Louis Trenker's Berge in Flammen. Whole mountain peaks at the Alps were exploded during the mountain war. Col di Lana, Lagazuoi and Marmolata, were a few of these peaks.

WW1 remains and memorial

Many of the largest craters have been left, often too large to fill even to this day.

The largest crater on the Western Front is called Lochnagar Crater, created by a mine blown under the German Front Line on the Somme battlefield on 1st July 1916. For 50 years it had been left in the landscape, but had begun to be used by motorbikers and a dump for rubbish. Privately purchased in 1979, it is now a recognized 1914-1918 historic battlefield site.

Operations since WW1

Because World War II troop movements were too fluid, and tunnelling too slow, mining proved not to be worth the investment of effort. Tunnelling was used in the Vietnam War, by both sides.