Tunnelling companies of the Royal Engineers

Royal Engineer Tunnelling Companies
Active	World War I
Country	United Kingdom
Branch	British Army
Type	Field corps
Garrison/HQ	St Omer/Aldershot
Nickname(s)	"The Moles"
Engagements	World War I Battle of Hill 60 Battle of Aubers Ridge Battle of Mont Sorrel Battle of the Somme Battle of Messines Battle of Vimy Ridge Battle of Arras (1917) Second Battle of Passchendaele
Commanders
Notable commanders	Major John Norton-Griffiths MP

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.

The siege situation of the early part of the war led to the deployment of tunnel warfare. After the first German Empire 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.

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, a tactic particularly used in the Battle of Arras.

Background

Main articles: Mining (military) and Tunnel warfare

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.

Early formations

In 1346, King Edward III requested that miners from the Forest of Dean, Gloucestershire accompany his expedition to France.

In 1770, the Company of Soldier Artificers formed in Gibraltar a specialist tunnelling troop to create defensive positions into the Rock of Gibraltar.

The Corps of Royal Engineers were formed in XXX, and their first deployment as specialist tunnelling miners was during the siege of Lucknow, where they were asked to undertake counter-mining.

WW1 Trench warfare

French Army Trench in northeastern France

Main article: 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.

However, although equipped with Royal Engineers who were given trained in carrying out sapping, mining and tunnelling operations, there was no core team of specialist skills.

Initial formation

Request and proposal

Even before it became apparent that the Germans were mining to a planned system, on December 3, 1914 the commanding officer of the British IV Corps, Sir Henry Rawlinson, requested the establishment of a special battalion to assist with mining duties.

Major Sir John Norton-Griffiths MP, founder of the Royal Engineer tunnelling companies

Towards the end of 1914, the civil engineering company of Member of Parliament and Major in the British Army, John Norton-Griffiths, was working on sewerage renewal contracts in Liverpool and Manchester. The relatively small bore tunnels were being driven by a manual technique known as "clay-kicking." Only useful in firm clay soils, the man doing the digging sat with his backs supported by a wooden backrest and with his feet pointing towards the cutting face. With a spade-like tool they dug out the clay ahead, passing the spoil over their heads to one of their mates for disposal at the rear. In early December 1914, Norton-Griffiths wrote to the War Office suggesting that the technique would be useful within the war effort for attack, spying or for intercepting German tunnels coming in the opposite direction. He concluded by asking to be allowed to take a group of his "moles" to France where if the soil was right, they could quickly undermine enemy positions. His letter was filed.

First German mine attack

On December 20, 1914, by placing shallow tunnels through No Man’s Land, Germans sappers placed eight 50 kilograms (110 lb) mines beneath the positions of the Indian Sirhind Brigade in Givenchy. Following their concurrent explosion, a German infantry attack resulted in the loss of the entire Indian company of 800 men.

Kitchener responds

Following further attacks, by January 1915, it was evident that the Germans were mining to a planned system. As the British had failed to develop suitable counter-tactics or listening devices, Sir John French, commander of the British Expeditionary Force wrote to Secretary of State for War, Lord Kitchener, describing the seriousness of the German mining situation.

On February 12, 1915, Norton-Griffiths received a telegram instructing him to report to the War Office. On arrival, he was shown to the private offices of Kitchener, who showed him French's letter. Kitchener then asked Norton-Griffiths for his advice, to which using a coal shovel from the room's fire grate, he sat on the floor and gave a demonstration of "clay-kicking."

Impressed but sceptical, Kitchener asked Norton-Griffiths to travel that day to France to communicate his method to the commanders there, and confirm the suitability of the Flanders soil. If positive, then he would raise a suitable battalion of "moles" as Norton-Griffith's had termed his new teams, the same name for their civil engineering counterparts.

Norton-Griffiths visits GHQ, France

Arriving with two of his employees in the GHQ St Omer office of the Engineer-in-Chief (E-in-C), Brigadier George Henry Fowke, on February 13, Norton-Griffiths gave another demonstration of "clay-kicking." A sceptical Fowke instructed his assistant Colonel Harvey to take Norton Griffiths and his employees to Army and Corps headquarters on February 14, to see what the Corps of Royal Engineers thought of the idea.

In an early public relations exercise, on February 14, Norton-Griffiths got Colonel Harvey to stop at the four headquarters: Army, Corps, Division and Brigade. At each briefing, Norton-Griffiths repeated his demonstration. On arrival at the front line, a mile from where the first German mine had gone off the previous December, they confirmed the excellent conditions of the clay-based soil, and returned to St Omer via the four headquarters to communicate their findings.

The following day, the team held further meetings in St Omer, closing out the proceedings with a meeting between Norton-Griffiths, Fowke and Sir John French, the C-in-C, for a personal explanation. Fowke gave his agreement to a trial which French agreed to, and the three set out a structure for what were to be called tunnelling companies, in opposition to Norton-Griffiths preference of moles: a symbol which many of the tunnelling companies would later adopt as their unit sign.

On February 17, in meetings with Lord Kitchener, he reported back on his visit to France, and the agreement of Collins and Fowkeat to form trial tunnelling companies. Norton-Griffiths however pointed out that to deploy the units at the speed which Lord Kitchener had suggested, would require the recruitment of civilians, who could not undergo initial military training to enable their immediate deployment to the front line. Kitchener's staff were highly sceptical of the proposal, but using his carte-blanche skill to cull such skilled men from regular infantry, Norton-Griffiths won his argument.

First tunnelling companies

On February 18, Norton Griffiths travelled to Liverpool and closed down one of his tunnelling contracts, making 18 staff redundant. The following day the War Office gave approval to the Royal Engineers tunnelling company scheme. On the same day, 18 formerly redundant Liverpool men turned up in Chatham to be enrolled, clothed and made into Royal Engineers. One of the most rapid acts of the First World War, men who were working underground as civilians on February 17, were working underground on the Western Front on the following Monday, a mere four days later.

The first nine Royal Engineer Tunnelling Companies, numbers 170 to 178, were each commanded by a regular R.E. officer, comprised: 5 officers; 269 sappers; aided by temporarily attached infantrymen as required which almost doubled the companies number. Norton Griffiths, in the rank of major, acted as liaison officer between these units and the E-in-C's office in St.Omer.

Although able to select almost any sign-up soldier he wished to, as he had predicted Norton-Griffiths was quickly forced to recruit civilians. The new recruits in these units, aged anything up to 60, did not readily conform to military discipline and Norton Griffiths' skills as a politician and an engineer were called on to the full in recruiting the men he needed and integrating them into a military environment. His judgement of people was remarkably accurate, and he very rarely made a mistake in selecting men for a commission.

The deployment of the first eight units led to the introduction of a tunnelling method that allowed the British to dig tunnels at a rate of 8 metres (8.7 yd) per day, compared to the German's 2 metres (2.2 yd).

First action: Hill60, Ypres Salient

First deployed in the Ypres Salient with the 28th Division, the specialist tunnelling companies laid six mines by April 10, 1915. These mines (together with other unfinished mines) were filled with around 10,000 pounds (4,500 kg) of Ammonal explosives, with the resulting explosions ripping the heart out of Hill 60 over a period of some 10 seconds. The effect resulted in an earthquake that split the ground under the entire hill with white flames shooting 300 feet (91 m) in to the sky, the concrete pillboxes and occupying soldiers came down 300 yards (270 m) in all directions. The explosion resulted in a 70 feet (21 m) deep crater, with surrounded trenches sandwiched shut so fast soldiers were crushed still in the standing positions. Enemy all around were crying with fear. The resulting terror resulted in German retreats and castigation of then tunnel master Otto von Fusslein, although the position was quickly recaptured days later.

The action showed the importance of the necessity for a counter-offensive against aggressive German mining against the British lines. Having proven the system, Norton-Griffiths left the company and returned to London in April 1916, mainly to return to his duties as an MP. He left GHQ with his August 1915 rough plan for extensive mining on the Messines front, which refined formed the framework on which mines used at the Battle of Messines two years later. He was awarded the DSO for his efforts, was mentioned in dispatches three times, and promoted to Lieutenant Colonel in 1916.

Expansion

The success of the Tunnelling Companies led to mining being made a separate branch of the new E-in-C Major-General S.R. Rice's office, and appointment of an Inspector of Mines at GHQ.

The second group of the tunnelling companies were formed from Welsh miners from the 1st and 3rd Battalions of The Monmouthshire Regiment, who were attached to the 1st Northumberland Field Company, Royal Engineers, a Territorial Force. Twelve Tunnelling Companies were ultimately formed in 1915, and one additional one in 1916. A Canadian troop formed from troops in the battle field, plus two others companies trained in Canada and then shipped to France; three Australian, and one New Zealand tunnelling companies were formed by March 1916. This resulted in 30 tunnelling companies by the end of 1916, many made up of ex-miners.

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.

Recruitment

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.

The mining assistants who acted as beasts of burden were often made up of "Bantams", soldiers of below average height who had been rejected from regular units because they did not meet the height requirements.

Digging

As tunnels were vulnerable to attack, the entrances were a closely guarded secret. With electricity in short supply on the frontline, 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.

Tunnel entrances were most often at the bottom of deep shafts. From here, using clay-kicking techniques, the tunnels were aligned and given direction by simple candlelight techniques, built on a slight uphill gradient of between 1:100 and 1:50 to keep them as dry as possible. This also however meant that they were vulnerable to gas accumulation at the digging face.

A clay-kicking team typically consisted of three men:

• Kicker: who works at the face
• Bagger: who fills sandbags with the lumps of clay spoil
• Trammer: who transports the bags out of the gallery on a small, rubber-tyred trolley on rails; on the return journey this was employed to bring timber in

If the tunnel was long, the trammer was given extra assistants, to speed the exit of spoil and intake of timber. The team was responsible for its own safety, and would insert a sett of wood supports every 9 inches (0.23 m). As no nails or screws could be used due to noise, the setts (consisting of a sole, two legs and a cap), were sawn with a rebated steps, which once trimmed into the clay, would expand with the absorbed water into a solid structure.

Health

Working in cold, cramped conditions and often up to a foot deep in freezing water, miners worked in 6 or 12hour rotating shifts. Due to these conditions, miners 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.

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 later small birds, such as canaries. With high metabolic rates, they were highly susceptible to gas, and 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.

In extensive tunnelling systems, air-tight doors were introduced to control air flows.

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 shaft head 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, and in 1917, Clifford was awarded the Meritorious Service Medal for what he had achieved.

From July 1916, under Logan's new organisation organisation, the second Army Mine-Rescue School was established at Armentieres. This allowed the British to deploy a system of mines rescue, where no mining shaft was further than 200 metres (220 yd) from a rescue station. Named after the breathing kit they employed, Proto-men were hand-picked experienced miners, selected for coolness under pressure. Two men were on duty at all times, with additional access to: 10 electric miners lamps; six canaries; four mobile cages; one saw; one hand axe; three life lines; two mine stretchers; one trench stretcher; one Primus stove; two tins of café au lait; six hot water bottles; six blankets.

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.

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.

British advantages

The British tunnellers had three advantages over their German counter parts, the German Pioniere Corps.

Firstly, the British used clay-kicking which was a virtually silent method of tunnelling. The Germans did not know of this technique, having not used it in their pre-war civil engineering, and thus used mattocks and other loud tools throughout the war. This made their tunnels vulnerable to detection and attack.

Secondly, the use of clay-kicking made the British four times as fast at tunnel digging as their German counterparts.

Thirdly, British positions were most often during the war on the low lands, while German positions were in the highlands. Although this made the British more vulnerable as an army to shelling, it also meant that British tunnellers had less of the soft quicksand like Kemmel Sands (known to the Germans as schwimmsands), an integral component of the geological make up of all the ridges around Ieper, to penetrate. While the bottom blue clay layer was virtually flat, as was the Kemmel Sands that sat on top of it, there was a dry starta which varied above this to create the geographical contours. This varying dry strata increased pressure on the Kemmel Sands, which unable to egress water below them, made them wet and unstable. Often, when punctured, the Kemmel Sands would "spout" under pressure both water and solid. Difficult to dig through and keep the mining wooden structure stable, the Germans, assuming that the British had the same instability problem, dug few tunnels until 1916. The British found an engineering solution by creating a metal tube through the Kemmel Sands. Sunk either through its own weight or by use of hydraulic jacks, once the blue clay layer was hit, the tunnelling could again resume under wooden supports.

The British used tube shafts from May 1915, a full year before the German's, who when they did start to use metal and concrete tunnels, had lost the strategic advantage and were purely digging for defensive purposes.

Operations

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 April 10, 1915. Mining was used increasingly at The Bluff, St Eloi, the Battle of Aubers Ridge in May 1915, Hooge, Givenchy, Cuinchy 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

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

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.

Tunnelling companies involved in the Battle of the Somme were 174th, 178th, 179th, 181st, 183rd, 252nd units.

Battle of Messines

The Lochnagar Crater, showing its memorial cross

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.

In preparation of the attack, six mines were exploded on March 27, 1916. The biggest of these was at St Eloi, dug by the 1st Canadian Tunnelling Company, consisting of 95,600 pounds (43,400 kg) of explosive. This allowed the capture of St Eloi by the British 41st Division.

This choice 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.

Battle of Vimy Ridge

Preserved World War 1 fighting tunnel in Vimy sector

Main article: Battle of Vimy Ridge

In preparation for the Battle of Vimy Ridge between 9th and 12th April, 1917, the British XVII Corps, commanded by Lieutenant-General Sir Julian Byng, relieved the French Tenth Army in the sector in February 1916, permitting the French to expand their operations at Verdun. The British soon discovered that German tunnelling companies had taken advantage of the relative calm on the surface to build an extensive network of tunnels and deep mines from which they could attack French positions. Royal Engineers immediately deployed specialist tunnelling companies along the front to combat the German mining operations. In response to increased British mining aggression, German artillery and trench mortar fire intensified in early May 1916. On 21 May 1916, after shelling both forward trenches and divisional artillery positions from no less than 80 out-of-sight batteries on the reverse slope of the ridge, the German infantry attacked the British lines along a 2,000-yard (1,800 m) front in an effort to eject them from positions along the ridge. The Germans successfully captured several British-controlled tunnels and mine craters before halting their advance and entrenching their positions. The Germans grew uneasy about the proximity of the British positions to the top of the ridge, particularly after the increase in British tunnelling and counter-mining activities.</ref> Small counter attacks by units of the 140th and 141st British Brigades took place on 22 May, but did not manage to change the situation. The Canadian Corps relieved the British IV Corps stationed along the western slopes of Vimy Ridge in October 1916.

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.

According to the original trench maps, hospitals, mess rooms, chapels, kitchens, workshops, blacksmiths, as well as bedrooms where exhausted soldiers could rest, were hewn from the blue-clay and stone. Connected by corridors measuring 6ft 6in high by 4ft wide, they were fitted with water pumps but, when the troops left within weeks of the war ending, they were slowly submerged. The developments at Hill 60 housed up to 3,000men, those near Hooge 1,000, while a brigade headquarters at the Vampire dugout near Zonnebeke, was captured and occupied by the Germans in their Spring Offensive in 1918, before being retaken in September 1918. The level of activity can be gauged by the fact that during 1917 and 1918, more people lived underground in the Ypres area than reside above ground in the town today.

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

Heavy trench mortar emplacement, constructed by the No. 2 Section of the 3rd Australian Tunnelling Company

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 inscription on the base of the Cross of Sacrifice, RE Grave Railway Wood Commonwealth War Graves Commission Cemetery.

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.

The RE Grave Railway Wood Commonwealth War Graves Commission Cemetery was founded by Commonwealth troops in November 1915 and remained in use until August 1917. It commemorates the eight men of the 177th Tunnelling Company, Royal Engineers, and the four assistant infantrymen who were killed whilst tunnelling under the hill. Their bodies were left in situ, beneath the hill on which the memorial now stands.

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.

Awards

Two members of the Tunnellers Companies were awarded the Victoria Cross:

List of Royal Engineer Tunnelling Company Awards

Name	Rank	Company	Location	Date	Unit	Held by	Notes
William Hackett	Saper	Corps of Royal Engineers	Givenchy-lès-la-Bassée, France	26 June, 1916	254 Tunnelling Company, Royal Engineers	Royal Engineers Museum	Posthumous. Commemorated at the Tunnellers Memorial
Coulson Norman Mitchell	Captain	Royal Canadian Engineers	Canal de I'Escaut, north-east of Cambrai	8-9 October, 1918	1 Tunnelling Company, 4th Canadian Engineers	Canadian Military Engineers Museum, CFB Gagetown, New Brunswick

See also

• 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.