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 volunteers taken the coal mining communities of South Wales, Scotland and the Northeast of England covering Derbyshire, County Durham, Nottinghamshire 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 in the First World War 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 across South Wales, Scotland and the Northeast of England covering Derbyshire, County Durham, Nottinghamshire and Yorkshire. 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.

With tunnel entrances a closely guarded secret, and electricity in short supply, tunnellers were forced to work in candlelight. Operating in near silence to avoid detection by the enemy, the tunnels were cold, cramped and often up to a foot deep in freezing water. Miners worked in 12hour rotating shifts, but due to conditions were prone to illness, with high rates of bad food disease, while fatigue compounded the problems to create a high mortality rate. Resultantly as a pre-caution, miners were billeted quite far back from the front line, while a regular Royal Navy-style rum ration was issued to keep out the cold.

Counter tactics

Listening

Early tunnelling required a great deal of improvisation, as equipment was in short supply. This made tunnels shallow and resultant noises loud, detectable using simple devices in the trenches even amongst the gun fire.

In the trenches, soldiers found that driving a stick into the ground and holding the other end between their teeth enabled them to feel any underground vibration. Another method involved sinking a water-filled oil drum into the floor of the trench, with lookout soldiers taking turns to lower an ear into the water to listen for vibrations. Later improvised methods included Water Board inspector short sticks each with a single vibrating wire-type earphone attached, or using filled heavy French water-bottles laid flat on their sides in pairs, so they could be listened to through medical stethoscopes.

Underground within the tunnelling operations, in side shafts the Armies 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.

Gases

Natural gases and gases given off as a result of explosions could ignite, poison or asphyxiate.

The major problem gas for tunnellers was Carbon Monoxide, given off by all armaments from shells to rifle bullets. Heavier than air, as the tunnels lay below surface level, during heavy attacks by both sides, the gas would pour down the tunnel shafts and accumulate.

With the use of experienced miners, came the use of "miners friends" in the form of mice and small birds, such as canaries. Highly susceptible to gas, they were issued to the Tunnelling Companies as an official item. When gas was present, their unconsciousness would alert miners to the need to evacuate. Although many animals died, they could recover on the surface, with at least one company keeping a record of the gassings so that their creatures did not have to endure more than three times before being pensioned off to an aviary. The role of the miners friends are honoured upon the Scottish National War Memorial in Edinburgh.

Mines Rescue

Such was the reliance on mining during the early siege stage of the war, that eventually casualties due to mining disasters became so great the War Office decided something had to be done. The skilled mining volunteers were particularly hard to replace, although also the most used to the deployment of mine safety techniques. In one six week period, one tunnelling company had: 16 killed; 48 sent to hospital; and 86 minor cases treated at the shafthead and returned to company billets. Another company in one month had: 12 killed by gas; 28 sent to hospital; and 60 minor cases retained with the unit.

In response to the affected mining units put out an urgent call for appropriate rescue apparatus, in June 1915, Lance Corporal Arthur B. Clifford was made solely responsible for mine safety training. Sent to the front to train 3000 mine rescue troops in a month, there were only 36 sets of PROTO being available in the whole of the United Kingdom. In September 1915, Captain D Dale Logan was appointed advisor to GHQ on all matters connected with the health of the specially enlisted Tunnelling Companies.

Clifford was based with the Royal Engineers at Strazeele, with a sub-station at Berguette. This became the first Army Mine-Rescue School, which was supplemented in the July 1916 under Logan's new organisation organisation, with the second school at Armentieres. In 1917, Clifford was awarded the Meritorious Service Medal for what he had achieved.

Underground fighting

As a result of so much mining activity by both sides, detection and breakthrough into each others tunnelling systems often occurred. The result was often the deployment of the emergency camouflet, with a pre-prepared and charged one always ready in the British and Allied forces sectors when tunnelling was taking place. The alternate was vicious hand to hand fighting in the dark with picks, shovels and wood used as weapons. Although all miners were trained to use rifles, the restrictions of tight tunnel construction often meant they were impossible to deploy. If the opposing side were unsuccessful in repelling an attack, then often enemy tunnels could be used for short periods to survey enemy tunnelling activity and direction.

Operations

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

Mining companies were not popular amongst the ordinary troops. Knowing a tunnelling company was nearby made them nervous, with a triple blow:

• Danger from above the ground (from the enemy)
• Danger from below the ground (from their own and enemy tunnelling companies)
• If the enemy knew a tunnelling company was in the area, it made the trench troops a more likely shelling target

This was further emphasised as the war developed with both sides using larger and larger mines, often deployed closer to their own trenches. These were both more likely not to go off on time, or if they did shower debris over their own trenches and advancing troops, increasing casualties.

The first British mine was detonated at Hill 60 on February 17, 1915. Mining was used increasingly during the Battle of Aubers Ridge in May 1915, and the Battle of Loos in September 1915.

Battle of Mont Sorrel

Main article: Battle of Mont Sorrel

Hooge, a small village in Flanders, was the site of a château which changed hands a number of times in the Ypres Salient. Used as the Divisional Headquarters for the area, the staff at the château, from the 1st and 2nd Divisions were all killed when the château was shelled on October 31, 1914. German forces attacked the château between 24 May and 3 June 1915, and, despite the detonation of a British mine by the 3rd Division, leaving a massive crater, took control of the château and the surrounding area on 30 July. The château and the crater (craters being strategically important in relatively flat countryside) were taken by the British 6th Division on 9 August. It was reclaimed by the Germans on 16 June 1916 and retaken by the British on 31 July 1917 when the 8th Division managed to push past it by about a mile. The Germans retook the site in April 1918 as part of the Spring Offensive but were expelled from the area by the British on 28 September as the Offensive faltered. During this time, the chateau was completely destroyed along with the entire village; several large craters from underground mines were blown over the course of the 1917 fighting.

Battle of the Somme

Main article: Battle of the Somme

When the Battle of the Somme started on July 1, 1916, the pan was to explode ten mines, the northern most of which was that under the Hawthorn Ridge Redoubt, a front-line fortification west of the village of Beaumont Hamel on the Somme. The other two biggest were the Lochnagar mine, and the Y Sap mine at La Boisselle. The Hawthorn Ridge Redoubt mine was 40,000 pounds (18,000 kg) of explosives. The plan was to detonate all other mines at 7:28 am, two minutes before Zero hour when the infantry advance would begin, but a compromise was reached with Lieutenant-General Aylmer Hunter-Weston, whose VIII Corps was holding the Hawthorn Ridge sector, allowing him to explode the mine at 07:20. This lead to the successful filming of the explosion by British cinematographer Geoffrey Malins, who was filming the 29th Division's attack. He had his camera set up about 0.5 miles (0.80 km) away, trained on the ridge and waiting for the explosion.

Battle of Messines

Main article: Battle of Messines

In January, 1917, General Sir Herbert Plumer, gave orders for 22 mines to be placed under German lines in preparation for the Battle of Messines.

From 1915, British engineers started digging, but it was not until the winter of 1916 when they were joined by Canadian, Australian and New Zealand engineers that mass tunnelling started under the German trenches. Twenty two mines were dug, some up to 2,160 feet (660 m) long and up to 125 feet (38 m) deep, laying 600 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 eventually 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." The mine at Petite Douve Farm was discovered by German counter miners on August 24th, 1916 and destroyed by a countermone. Two mines close to Ploegsteert Wood were not exploded as they were outside the attack area. This reduced the total explosive to 450 tonnes. 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

With doubts of the reliability of the system, with some mines having been lying underground for over a year, soldiers waiting in the trenches had been warned that they could not depend absolutely on the mines working as planned, and their orders were to leave their trenches and attack whether the mines exploded or not. The simultaneous explosion of the mines took place at 03:10 on June 7th. Approximately 10,000 German troops were killed when the 19 mines were simultaneously detonated, creating an explosion so loud it was heard by British Prime Minister David Lloyd George, who was in his study in 10 Downing Street in London. There is even a report of an insomniac student hearing it in University College, Dublin.

The largest of the 19 Messines mines was at Spanbroekmolen. Found and counter mined by the Germans a few weeks before the attack, the British were forced to dig a second entrance tunnel into the already prepared explosive chamber, which consisted of 41 tons of ammonal explosive located 88 feet (27 m) below ground, to reconnect the detonation wires. Tested fully but a few hours before the attack, officers used torch batteries to prove the circuits. As instructed, soldiers of the 36th (Ulster) Division had already left their trenches and begun to race across No-Man's Land when the mine exploded a few seconds late, leading to some being killed by falling debris. They are buried in Lone Tree cemetery nearby. The "Lone Tree Crater" formed by the blast was approximately 250 feet (76 m) in diameter, and 40 feet (12 m) deep.

The 1st Australian Tunnelling Company took over mining operations in November 1916 on Hill 60, led in part by Capt. Oliver Holmes Woodward. The explosion demolished a large part of the hill, killing many German soldiers occupying the trenches.

The British intended to dismantle the two remaining bombs, but the Third Battle of Ypres delayed operations, and after the Germans overran the group headquarters their location was lost. On July 17, 1955, a lightning strike set off one of the remaining mines. There were no human casualties, but one cow was killed and some local property damage sustained. The 21st cache was never found, and there are still several tonnes of high explosive buried somewhere in the Belgian countryside. A memorial to the Australian mining troops killed at Hill 60 during the course of the war was later placed at the site.

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.

End of mining operations

From Spring 1917 the whole war became more mobile, with grand offensives at the Battles of Arras, Messines and Passchendaele, there was no longer a place for a tactic that depended upon total stasis for its employment. As the tactics and counter tactics requiring deeper and deeper tunnelling, hence more time and requiring more stable front lines, offensive and defensive military mining largely ceased.

Underground work continued, with the tunnellers concentrating on mined deep dugouts for troop accommodation, safe from the larger shells being deployed.

Battle of Arras

Main article: Battle of Arras (1917)

Exit from the Allied military tunnels in the Carrière Wellington

In preparation of the Battle of Arras in 1917, from October 1916, the Royal Engineers had been working underground to construct tunnels for the troops. The Arras region is chalky and therefore easily excavated; under Arras itself is a vast network (called the boves) of caverns, underground quarries, galleries and sewage tunnels. The engineers devised a plan to add new tunnels to this network so that troops could arrive at the battlefield in secrecy and in safety. The scale of this undertaking was enormous: in one sector alone four Tunnel Companies (of 500 men each) worked around the clock in 18-hour shifts for two months.

The British attack plan was well developed, drawing on the lessons of the Somme and Verdun of the previous year. Rather than attacking on an extended front, the full weight of artillery would be concentrated on a relatively narrow stretch of 24 miles (39 km). The barrage was planned to last about a week at all points on the line, with a much longer and heavier barrage at Vimy to weaken its strong defences. During the assault, the troops would advance in open formation, with units leapfrogging each other in order to allow them time to consolidate and regroup. Before the action could be undertaken, a great deal of preparation was required, much of it innovative.

To enable the attack, Royal Engineers constructed 20 kilometres (12 mi) of tunnels, graded as subways (foot traffic only); tramways (with rails for hand-drawn trollies, for taking ammunition to the line and bringing casualties back from it); and railways (a light railway system). Just before the assault the tunnel system had grown big enough to conceal 24,000 men, with electric lighting provided by its own small powerhouse, as well as kitchens, latrines, and a medical centre with a fully equipped operating theatre. The bulk of the work was done by New Zealanders, including Maori and Pacific Islanders from the New Zealand Pioneer battalion, and Bantams from the mining towns of Northern England.

Assault tunnels were also dug, stopping a few metres short of the German line, ready to be blown open by explosives on Zero-Day. In addition to this, conventional mines were laid under the front lines, ready to be blown immediately before the assault. Many were never detonated for fear that they would churn up the ground too much. In the meantime, German sappers were actively conducting their own underground operations, seeking out Allied tunnels to assault and counter-mine. Of the New Zealanders alone, 41 died and 151 were wounded as a result of German counter-mining.

Today, most of the tunnels and trenches are currently off-limits to the public for reasons of safety. A 250 metre portion of the Grange Subway at Vimy Ridge is open to the public from May through November and the Wellington tunnel was opened to the public as the Carrière Wellington museum in March 2008.

Second Battle of Passchendaele

Main article: Second Battle of Passchendaele

In preparation for the Second Battle of Passchendaele, as early as the 17 October, assaulting units were given all available details about the German defenses in their respective sectors, in order to facilitate early assault planning. Intelligence officers and artillery observers worked jointly in observation posts recording newly build German fortifications as well so those that had previously escaped notice, permitting the artillery to take necessary actions before the offensive. To improve the logistical movement of artillery and supplies an extensive program of road building was started. Ten field companies, seven tunnelling companies, four army troop companies and nine battalions were put to work repairing or extending existing plank roads. From the middle of October until the end of the offensive, a total of 2 miles (3.2 km) of double plank road and more than 4,000 yards (3,700 m) of heavy tram line were constructed in the Canadian Corps area. Brigadier General Edward Morrison, commander of the artillery, also secured permission to use the roads to the rear for getting disabled guns back for repair.

WW1 remains and memorial

The Lochnagar Crater, showing its memorial cross

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

The largest crater on the Western Front, Lochnagar Crater, for 50 years 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.

See also

• Coulson Norman Mitchell VC MC (11 December 1889 – 17 November 1978), Canadian Captain in the 1st Tunnelling Company, 4th Canadian Engineers
• Beneath Hill 60 a 2010 Australian war film, directed by Jeremy Sims and written by David Roach, tells the story of the 1st Australian Tunnelling Company The screenplay is based on an account of the ordeal written by Captain Oliver Woodward, who is portrayed by Brendan Cowell

References

Alexander Barrie. War Underground - The Tunnellers of the Great War. ISBN 1-871085-00-4. The Work of the Royal Engineers in the European War 1914 -1919, - MILITARY MINING.