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An Introduction to The Mine Craters of Messines Ridge, Cratering the Ridge

Updated: Apr 10, 2023

Traces in the landscape

Messines is to the tunneller what Waterloo was to Wellington. Never in the history of British warfare has a miner played such a great and vital part in a battle. The tunnelling and mining operation at Messines were a staggering feat of engineering by the Tunnelling Companies.

IWM E (AUS) 4621 The 2nd Australian Tunnelling Company at work underground. 14 November 1917 at Nieuport Bains, Belgium.

The Battle of Messines was the most effective integration of mines with an infantry attack and saw the largest quantity of explosives detonated at the same time. The aim of this blog, and the supporting blogs in the series about each of the mine craters, is to give the reader a brief history of the extraordinary story of the part played by the Tunnelling Companies who dug the mines that cratered Messines Ridge at 3.10am on 7 June 1917. The supporting blogs tell the story of the creation of each mine and the craters that remain today and stand as monuments to the work of the Tunnelling Companies. The reader can obtain more detailed insight into the murderous business of mining and counter-mining by using the reading list at the end of this blog.

Linesman map showing British and German trenches at Petit Bois

In his diary published with the title ‘Armageddon Road A VC’s Diary 1914 -1916’, Billy Congreve, then a Lieutenant in the 3rd Division, Rifle Brigade, described the British trenches at Petit Bois, located to the south of the village of Wytschaete, he wrote on the 19 December 1914: ‘In one particular place in our line there is a trench called ‘dead boot ditch’, and one is shown by the inmates with some pride a protruding Boche’s foot where it sticks out from the side of the trench. Everyone is quite friendly with the gruesome boot… It is interesting to think what a section of one of these trenches will look like when dug up in years to come by some research party – dead British, German and French soldiers, rifles, equipment, bully beef, biscuits, spades, ammunition, Tickler’s jam, all mixed up with wood, straw and mud and forming various strata.

Rather prophetic words that betray how symbolic the Flanders landscape had become to Congreve’s generation only four months into a four-year war of attrition, and for us, the research party, how we would pour over the Flanders landscape in order to better understand the events and conditions that formed that bitter conflict in the Salient - the Immortal Salient as it became known after the war.

Crownhole at Petit Bois. Authors image.

Today, the battlefields of the Salient have been reclaimed by nature, the farmers plough or the builder’s bulldozer. New roads, housing, industrial estates, and industrial farming have reshaped much of the old battlefields. There are still traces in the landscape for the battlefield tourist to experience the ‘authentic’ Salient and in the case of the war underground, the occasional limited collapse, a crack in a wall or a hole in a farmers field gives the visitor clues to the underground war as well as the various mine craters still visible in the landscape.

The story of the Messines mines is a protracted one, not because of the time taken in driving the galleries and placing the charges, but because of the inordinate lapse of time between completing and firing them. It begins as far back as May 1915, in the early days of mining and when John Norton-Griffiths wrote to the War Office with his scheme. They rejected it at the time. It ends with the detonation of nineteen of the twenty-three mines at 3.10am on 7 June 1917. As you follow the front line at Messines Ridge and the mine craters trail you may be wondering to your self why those in the middle of the front line are grouped closely together and others are further apart. The plan was to destroy as many of the German strongpoints as they could and the British had actually planned for forty nine mines to be placed. Today, we accept that twenty five charges had been placed - La Petite Douve was lost to countermining and 'C' gallery at Peckham to geology - and many more were either completed or close to being completed by zero day. The reason the British blew nineteen mines on 7 June is because they were the only ones ready by zero day.

Dangerous and Stressful

EO 2094 Australian War Memorial Tunnellers Messines

The work of the tunnelling companies was dangerous and took its toll on the nerves of the men involved. In the early days of a tour of duty in the mines it was normally four days on and four days off however, with the increasing casualties and demands placed on the tunnellers, and with the expanding mining activities, this was changed to six days on and two days off. All Tunnelling company and section commanders were already given as much leave as possible, they were given more leave than an infantry officer, to enable them to cope with the strain and the constant danger, receiving fortnights leave every three moths if possible. Many officers had resorted to heavy drinking to control their nerves, Lieutenant John Westacott, working at Mount Sorrell, required a mug of rum each morning to get him going. Drunkenness was the main reason for field punishment in the tunnelling companies. In their book ‘Beneath Flanders Fields, The tunnellers War 1914-18’ the authors recount the comments from of Major RSG Stokes, RE, Assistant Inspector of Mines, when he wrote in his War Diary about Major AW Davis, who commanded the 3rd Canadian Tunnelling Company: ‘[Davis is] not fresh, Seems to have lost all his push and interest – now only waiting for the end of the war. His thoughts are thoroughly jumpy.

On the 25 April 1917, two officers of the 1st Australian Tunnelling Company were killed in an accident at Hill 60. Alexander Barrie, in his book 'War Underground, the Tunnellers of the Great War' recounted what happened: 'The two officers Captain Wilfred Avery and Lieutenant Arthur Tandy, were preparing a guncotton priming charge that was to be used to fire an ammonal camouflet. They passed a light current through the detonators after inserting them in the explosive (this should have been done before) and the charge, 50lbs. of it promptly fired. Avery and Tandy were blown to pieces and the entire dug-out they were in was wrecked; the blast flashed on through the corridor and into the Proto storeroom (where the gas equipment was stored) to take more casualties there.' Total casualties were three officers and seven men dead, four officers and twelve men gassed, many seriously. Barrie recounted the clearing up by Captain William McBride, who he described as a large and cheery extrovert mining engineer from Adelaide: 'He found sand almost filling the dug-out and sieved as much of it as possible, extracting the remains of the two distinguished officers which he wrapped in blankets and sent down for burial with the other bodies.' McBride was awarded the M.C. for completing this terrible task. Both Avery and Tandy are buried in Poperinge New Military Cemetery graves 1.EI.I and 1.EI.2.

An active Battle Zone

From a British perspective, the fighting in the Salient has always appeared as a permanent feature from First Ypres in 1914, to Second Ypres in the spring of 1915, and the fighting around Mount Sorrel in June 1916, to Third Ypres in the summer of 1917, the German spring offensive in 1918, and the advance to victory in September 1918. In truth, it was relatively quiet between June 1916 to June 1917 however, the spectre of being fired at from three sides brought its own horror to the British troops. For the Germans, their High Command had decided early on that the Flanders sector should not be an area that involved major attack, that said, Second Ypres was an attack that we are still trying to understand what the strategic objectives were to have been. The Germans also knew that the Salient would be a focus of British strategic planning and therefore, began, from late 1915 to the end of 1917, the ‘bunker’ phase in their defence development and to build a sophisticated defensive system that could adapt to the offensive weapons in particular, the weight and accuracy of the British artillery.

German artillery bunker. Authors image.

The Geology

In Flanders, just below the surface soil, which is a layer about one metre thick, is a layer of sandy loam, with underneath this, a layer of blue clay. The sandy loam has a limited permeability, the blue clay, known as Ypresian, today it has a less historically emotive description of Kortrijk Formation, in Britain it is known as London Clay. This is a marine geological formation, and it is virtually impermeable and shrinks when it is dry. It is about one hundred metres thick and hardly any water can penetrate through it. This clay was both a help and a hinderance to the engineers who worked with it and in it. It has a blue grey colour when freshly dug and this changes to a dull brown when it oxidises in the air.

Geological-section-north-south-through-the-Wytschaete-Messines-ridge. Source: Research Gate, Peter Doyle accessed April 2023. See also Disputed Earth, Peter Doyle.

The area is very fertile for farming purposes however, it is also very marshy. The draining of the ground for farming began in the Middle Ages and this saw the digging of ditches and canals however, it was not until the mid-nineteenth century that field draining systems were put in place. It was this network of field drains and ditches that were destroyed by the artillery shelling of the First World War and affected the draining of groundwater and rainwater. It was also the clay that acted as a barrier to the drainage of water into the lower strata and so forming pools and a system of semi-permanent lakes that we see in the photographs. This resulted in the water filled trenches and dugouts that were dug as siege warfare took hold from late 1914 onwards. Gerald Burgoyne, officer commanding ‘D’ Company, 2nd Battalion Royal Irish Rifles, 7th Brigade, 3rd Division, was in the trenches in the Petit Bois area and recorded in his diary on 6 January 1915: ‘On my left the trench is nothing more than a water course, very little head cover, and only some 80 to 100 yards from the Germans in Petit Bois. Parts of my trenches (H2) we cannot even man; a spring runs through it, and the bottom in places is a sort of quicksand into which I have sunk to my knees, and the suction is so great a man cannot get out without help. Sent down some planks to build up the parapet where a man was killed yesterday’ To overcome this, trenches, on both British and German sides, were partially dug below the surface and mainly above the surface in effect breastworks predominated.

The Topography

The country, with its mixture of villages, hamlets, farmhouses, hedgerows, woodlands, made excellent locations and features for dugouts, bunkers and blockhouses for the German defenders and Allies alike. As well as being low lying, the area of the Salient has a series of low ridges each one slightly higher than the next and these formed a semi-circle to the north, east and south of Ypres. One such in the central part of the Salient, that offered the Germans excellent views over the British lines to the west and south, was the Gheluvelt Plateau. It equally gave good views over the rear area of the German positions. The Plateau, ran from west of Geluveld to Hooge, with Clapham Junction as the highest points, along with the Tower Hamlets Spur. In the north, Pilkem Ridge, a barely perceptible ridge, the Germans had their artillery observation points on this ridge so controlling the front line. Together with Houthulst Forest these ridges were of the utmost importance to the German defensive position in the Salient. In the south of the Salient the Germans occupied the high ground on the Messines Ridge. However, the British also had good observation high ground on Mount Kemmel and Le Rossignol (Hill 63) to the northwest of Ploegsteert Wood.

There are many ditches and small streams that cut across the Flanders countryside, and these divert the water to the Yser and Lys rivers. They also form excellent ready-made defensive trenches, if not rather muddy and wet. At Third Ypres the Germans made full use of these ditches and streams that had been destroyed by the shelling and had become wide, almost impassable, swamps. They built their barbed wire defences behind these swamps and had their trenches on the higher ground. To take the German positions, the attacking force had to not only negotiate the swampy ground, the German wire, but also attack up a gently rising slope before engaging the enemy. These were the conditions that the New Zealand Division’s encountered during their attack across the Ravebeek Valley towards the Bellevue Spur near Passchendaele on 12 October 1917. Their casualties, for a few hours of action, were 850 dead.

Establishment of the Corps of Royal Engineers

The British army had experience of mining before the First World War. It began, following the publication of Vauban’s influential paper on fortifications, and the establishment of a training school at Woolwich in the mid-18th century by John Muller, Professor of Fortifications and Artillery at The Royal Military Academy. In 1812, the Duke of Wellington called for the formation of a corps of Sappers and Miners, the Corps of Royal Military Artificers, subsequently renamed The Corps of Royal Sappers and Miners. In 1856, following a reorganisation, the Corps of Royal Engineers, with their battle honour Ubique – everywhere – was established.

British Military Mining Before 1914

Although the services of the Corps of Royal Engineers military mining was not required in the various colonial wars, regular practice was undertaken at Brompton Barracks, Chatham, Kent, the home of the Royal Engineers. In 1868, a practice mine attack was made against the old Napoleonic defences at St Mary’s Casements when nine practice mines were blown, craters ‘crowned’, and defensive ditches and moats blown in. These manoeuvres were designed not just to test the offensive capabilities but also the defensive mining capabilities including listening techniques and countermining.

Royal engineer Practice mines being blown near Chatham 1887. REM

In 1907 the largest mining manoeuvres took place, once again in Kent, and these practiced the latest techniques learned from the conflicts in South Africa and the Russo-Japanese war in Manchuria. Among the officers taking part was Lieutenant Colonel G H Fowke R.E. who would later become the Engineer-in-Chief of the BEF and in command of British military mining on the Western Front. Some twenty-six mines and camouflets were blown between 1 July and 20 August which made these the largest and most comprehensive practice mining operations in British military history.

In 1908, following the lessons learned from the Russo-Japanese war, two Fortress Companies and one Siege Company of Royal Engineers, was specially trained in mine warfare and siege works however, the equipment and gallery sizes remained unchanged from 1870. In June 1913, two R.E. companies, 20th and 42nd, undertook siege exercises I the area around Lulworth in Kent. The ground encountered was a mixture of waterlogged sand and clay to a depth of 3.5 metres, similar ground conditions that were to be encountered in Flanders. It was further noted that the ground conditions made the removal of the spoil difficult and the need for a pumping apparatus for the removal of the water, which was noisy, labour intensive and took up a lot of space in the galleries. They also noted the timber sizes that would best resist the shock of an underground explosion, later applied in Flanders. They also undertook experiments with self-contained breathing apparatus for protection against poison gas underground. Carbon monoxide gas was a dangerous by product of underground explosions from camouflets and they studied how long poison gases remained absorbed in the earth from the explosion of camouflets.

Whose Idea Was It To Crater the Ridge

John Norton-Griffiths

By the end of 1915, the Germans were ahead in mine warfare and were initiating every new attack. A radical British reply was needed in order to wrestle the initiative away from the Germans. It took an Imperial adventurer, businessman, he had his own mining company and was Conservative MP for Wednesbury constituency, one John Norton-Griffiths, better known as ‘Empire Jack’. He convinced the military authorities that not only was mining a possibility in the Flanders mud, but that without a mining organisation the BEF would soon be mined to bits by the Germans.

Before war broke out he formed his own Yeomanry cavalry battalion the 2nd King Edward’s Horse advertising in the Pall Mall Gazette in July 1914, under the heading ‘IF DUTY CALLS, MP’s INVITATION TO OLD FIGHTERS’, old friends and employees volunteered. He funded and equipped the battalion from his own funds. His battalion became one of the few privately raised battalions accepted into the British army. The 1st King Edward’s Horse, also a ‘colonial’ battalion never recognised Griffith’s battalion. Norton-Griffiths founded the Comrades of the Great War whose aims were to care for the veterans and the promotion of a bond of friendship after the war was over. It is said that he came up with the idea while in discussion with a sergeant in a trench near Ypres. Today, we know it as the British Legion.

Pall Mall Gazette 31 July 1914

In January 1915, the Germans blew twenty mines in the La Bassee – Cuinchy sector sewing confusion and panic in the British as they struggled to counter the Germans. In February 1915, Kitchener held a meeting with Norton-Griffiths to discuss Norton-Griffiths letter, submitted in November 1914 in response to the siege conditions developing on the Western Front. He had set out, despite not knowing the ground conditions in Flanders, the idea of his sewermen employees, they were driving the sewer tunnels of the Manchester Main Drainage Scheme, driving mine galleries using a system known as clay kicking. This involved a tool known as a grafting tool, a modified spade, which was worked with the legs, or kicked. Men lying on the floor of the gallery, with their backs partly supported by a plank wedged across it, would push their scoops into the face with their feet. In this way silent work was possible, and they used screws rather than nails to secure the timbers. It was ideal for tunnels or galleries that were too small to swing a pick. It was quick and efficient.

Having heard Norton-Griffiths plan Kitchener immediately demanded 10,000 clay kickers, an impossible number to be found. Despite reservations from GHQ about putting untrained men into uniform they requested an initial draft of 500 men. Norton-Griffiths referred to the men as ‘moles’ and he personally selected the first twenty to be sent from Manchester to the RE Depot at Chatham on 17 February 1915 and they formed the embryonic 170 Tunnelling Company.

Independent of Norton-Griffiths lobbying, Captain Cecil Cropper, commanding 250 Tunnelling Company, his HQ lay within the Canadian Corps at La Clytte, had been ordered by Brigadier-General Charles Armstrong, Canadian Chief Engineer, to come up with an aggressive plan to counter the German mining on his front. Cropper had concluded that it was no use trying to sink shafts in the front or support trenches. He went further back to where the blue clay formation was at a depth that they could reach. He sited a shaft in a wood in order to hide the works from the Germans and was successful in sinking a shaft down to the blue clay.

War Diary 250 Tunnelling Company. Croppers recommendation 13 Dec 1915

The Germans at this point were holding a defensive position on the high ground at Spanbroekmolen. He concluded that it would take a gallery of some 250 to 300 yards to get below the objective and a very large explosion in a deep charge. He also identified four other targets at Peckham Farmhouse , Maedelstede Farm, Petit Bois, and Hollandscheschuur Farm. He thought it was possible to destroy these targets by deep mining. He went to Armstrong with his plan who listened in surprise and gave the go ahead, adding that he would pass on the plans to 2nd Army headquarters.

War Diary 250 Tunnelling Company 17 Dec 1915. Croppers ideas are accepted

On December 18, 1915, Norton-Griffiths arrived at the Canadian HQ and by then Cropper had four shafts marked out and was already well down in three of them. He rather matter of factly informed Norton-Griffiths that he was aiming a four-gallery attack on the Messines ridge.

Cropper and Norton-Griffith leave the scene

Cropper’s plan for a five-tunnel attack have won a place in the history of warfare. Cropper was not present to see the fulfilment of his plan. In December 1916 he caught German measles and the Controller of Mines, Lt-Col Alexander Stevenson and the Medical Officer sent him off for treatment with Cropper protesting that he did not want to go. He never returned to Messines.

Norton-Griffiths also never saw the fulfilment of the plan he had presented to Kitchener. On the 21 March 1916, he asked to be relieved of his duties and requested two months leave effective from 1 April. He gave his reasons as having to attend to his private affairs which were of considerable importance. His request was granted. His last duty was performed on 29 March when he visited Captain Cecil Cropper and then Captain Henry Hudspeth at Ploegsteert Wood to inspect the mines at Trenches 121 and 127. Hudspeth said that Norton-Griffiths spent most of his time taking photographs, in contravention of the regulations, and that he promised to send a photograph to Hudspeth’s mother which he dully did. In the afternoon Norton-Griffiths went to Hill 60 and heard a report that a captured German had told of a countermine being driven towards the British tunnel known as the ‘Berlin Tunnel’. Lt-Col Stevenson, Controller of Mines was considering blowing a camouflet to disrupt the German plans. Norton-Griffiths opposed this on the basis that it would be a mistake however, as it was Stevenson went ahead and it proved to be the right decision. On the 30 March Norton-Griffiths left for England.

Cratering the Ridge: Messines, June 1917

The Messines Ridge is an extension of the Passchendaele Ridge and runs from Passchendaele through Broodsiende, Mount Sorrel, Hill 60, the Bluff and St Eloi and forms a broad plateau-like spur in an arc. Sitting on top of the northern end is the village of Wytschaete ‘Whitesheets’ and Messines is at the southern end overlooking Ploegsteert Wood ‘Plugstreet’. The ridge has a height of ninety-five metres and has magnificent views over the valley of the Douve and into French Flanders. On a clear day you can see Vimy and the coal mounds at Lens. The Messines Ridge had been controlled by the Germans since its capture in November 1914.

Clay-kickers of Flanders Fields: Canadian Tunnellers at Messines Ridge 1916-1917, Brian Pacas

The German Flandern Stellung, a defensive system of trenches and bunkers, extended across the higher ground and presented a major challenge to the British, Positioned on the down slope their artillery could not register on the German positions on top of the ridge. Following the lessons learned at the Somme the British recognised that an infantry assault would result in heavy casualties. However, the British had no intention of attacking using the conventional style of artillery and infantry style, the ‘moles’ of Norton-Griffiths had been tunnelling under the ridge for over a year. They were working on the largest co-ordinated mine attack in military history with the aim of obliterating the German strong points on the ridge and taking the ridge and Oostaverne Line beyond. In doing so they would create an earthquake to match the forces of nature herself.

The Plan

The British had been debating a concentrated mine attack in the Messines sector since mid-1915 and eventually in November 1915 GHQ took up Norton-Griffiths fantastic idea to ‘earthquake’ the ridge and the German defensive positions from St Eloi, Hollandscheschuur, Petit Bois, Maedelstede, Peckham, Kruisstraat and Spanbroekmolen. The plan was extended to take in Hill 60 and the ‘Birdcage’ at Ploegsteert. The plan envisaged was for twenty-three mines laid from twelve main shafts and tunnels however, as zero hour approached General Plumer decided that the ‘Bird Cage’ mines were outside the area of his intended attack, being too far to the right, and also the Germans would occupy the craters before the British infantry could reach them. The British had also lost a mine to German action at La Petit Douve. The revised plan now envisaged nineteen mines being detonated from eleven locations:

1. Hill 60/Caterpillar

2. St Eloi

3. Hollandscheschuur (3)

4. Petit Bois (2)

5. Maedelstede

6. Peckham

7. Spanbroekmolen

8. Kruisstraat (3)

9. Ontario Farm

10. Trench 127 (2)

11. Trench 121 Ultimo & Factory Farm (2)

The Tunnelling Companies tasked with the fulfilment of the plan were 171, 175, 183, 250, 1st, 2nd, and 3rd Canadian, 1st and 2nd Australian.

Throughout 1916 the British tunnelled under the German lines meanwhile, with the conclusion of the Somme offensive in November 1916, Field Marshal Douglas Haig now turned his attention to a long-cherished plan of a breakthrough at Ypres to push onto the Channel ports of Ostend and Zeebrugge to eliminate the German submarine threat and to take the important German railhead at Roulers.

General Sir Herbert Plumer, commander of the British 2nd Army was given the task. Plumer new the ground, he had been in command of V Corps during the Second Battle of Ypres and had been in the sector almost continuously. He planned a limited offensive at Messines using the deep mines to be followed by an infantry attack on Pilkem Ridge to the north of the Salient. Haig rejected the plan; he wanted a breakout from the Salient not limited objectives and sent Plumer back to rework the plan and was assisted by General Sir Henry Rawlinson (Haig had promised Rawlinson a command in the offensive to come).

Plumer presented the revised plan on 31 January 1917 and he now proposed that it encompass a sector-by-sector assault to clear the Passchendaele Ridge from Pilkem in the north sector to Messines in the southern sector. It also included the advance to the coast and linking an assault from the sea north of Nieuport. This audacious plan would require a lot of artillery and this artillery would have to be moved and relayed between the Messines and Pilkem attacks. Haig disagreed and sacked Rawlinson, whose idea it was, and appointed General Sir Hubert Gough who he considered more adventurous. Haig, on 7 May, changed the plan again, and decided that the Messines offensive was to stand alone and asked Plumer when he would be ready. Plumer replied, ‘one month from today’ So, the date was fixed for 7 June 1917.

The Explosives

In their pre-war period and in the early days of their mining operations the British engineers had used black powder packed in 100-lb sacks and guncotton in slabs of a few pounds in their mining operations. They had used other explosives such as amatol, blastine, sabulite, ammonal, cheddite, and gelignite. Gunpowder was replaced by Ammonal as it was easier to handle, safer since it could not be detonated by a bullet or flame and had three-and-a-half times the lifting power. Ammonal was composed of 65 percent ammonium nitrate, 15 percent TNT, 3 percent charcoal, 16 percent course aluminium, and 1 percent fine aluminium. The effect of the aluminium was to raise the temperature of the gases caused by the explosion so that the lifting effect was enormously increased, while the shattering effect of the Ammonium Nitrate and TNT was not reduced. This made it suitable for blowing large surface mines while its crushing effect on any enemy galleries within a given radius could be relied upon. It was also a powder which made it ideal for packing into tins or sandbags, and it would not explode if struck by a bullet, but only if fired by a detonator.

IWM Q 115 Battle of Albert. Laying a charge in a mine chamber. Note the officer using Geophone. July 1916.

It was stored either in 50-lb tins or 25-lb to 40-lb rubberised canvas bags clamped with wood slats. It was necessary to use water-proof rubberised bags because ammonal was liable to fail when it was damp. Detonation was triggered electrically (exploder or dynamo) the detonator fired a primer, which in turn fired the charge. Fulminate mercury detonator tubes were inserted into the guncotton primers.

NAM. 1998-11-87-1 25lb Ammonal bag

Tunnelling officer using a Geophone to listen for German activity

Listening for the enemy was one of the most important duties of a Tunneller. Special listening devices known as geophones; the French geophone was the best. This was an adaption of the donkey’s long ears from a doctor’s stethoscope and two microphones, which were placed on the gallery floor, were connected by rubber tubes to a headpiece that fitted over the ears. The microphones were moved around on the floor of the gallery until the sound appeared to the listener to be coming from straight in front of them and this indicated that it was coming from a direction at right angles to the line joining the two microphones. The compass bearing was noted and a further bearing was taken from an adjoining gallery with the intersection of the two lines indicating the position of the enemy. At Hill 60 the enemy was detected, just a few days before zero to be close to the mines it was calculated that by zero hour on 7 June, they would be within three feet of the mines prior to them being blown.

In order to disrupt or destroy enemy mining operations and their galleries a camouflet charge was used. This was tamped by placing sandbags behind the charge. Tamping prevented the explosion from flowing down the gallery instead of through the earth above the charge. Air spaces between piles of sandbags acted as shock absorbers of the explosion. This was achieved, for example, by 15 feet of tamping, a 10-foot air space, 10 feet of tamping, and another 10-foot air space sufficed for a 50-foot mine depth and sometimes timbers were strutted across the gallery to stiffen the tamping. Explosions released carbon monoxide (CO) gas, which remained trapped in the gallery.

IWM E(AUS) 1683 The interior of 3rd Australian Tunnelling Company's Mine Rescue Station The sapper wears the 'Proto' breathing apparatus and carries a small cage containing a white mouse or canary for testing the air conditions underground.

To counter the effects of CO gas, anti-gas breathing apparatus called Proto sets—in use at mine rescue stations at British coalfields—were utilised along with the Salvus breathing apparatus. The 32lb Proto set included two oxygen cylinders and a breathing bag containing caustic soda sticks—a carbon dioxide absorbent for exhaled air. Both Proto and Salvus apparatus were installed at life-saving stations along with Novita Pattern oxygen reviving sets. Every company had proto-men trained in the operation of breathing apparatus and in resuscitation techniques. Tunnellers using anti-gas breathing apparatus also took mice and canaries into the danger areas with them, both are sensitive to CO gas. On The Scottish National War Memorial in Edinburgh Castle, you can see figures of the Miners’ Friends. A large aviary was maintained by the Royal Engineers at Calais.


At 3.10am on 7 June 1917, the nineteen mines were blown that created an earthquake to match the forces of nature herself. This was the largest mining attack in the history of warfare. Major General R.N. Harvey issued orders for the safety of the British infantry and these are recorded in his mining report held at the National Archive: ‘Prior to firing of the mines it was necessary to frame such instructions to the assaulting troops as would obviate casualties resulting from the effect of the enormous concentration of explosive at the depth of 70-100 feet below the surface. There was no information to be obtained from history as no military mining had ever dealt with so many large charges from one operation.’ These precautions included no man being within 200 yards of a charge until at least twenty seconds had elapsed from the time of the explosion, all dugouts in trenches and surface dugouts within a 300 yard radius of the mine were to be cleared and no man was to be inside any structure that might collapse. Galleries and subways within 400 yards were to be cleared. Finally, the assaulting troops were not to enter the bottom of the craters due to the danger posed by explosive gas.

In his diary published under the title ‘The War Diary of the Master of Belhaven’, R.G. Hamilton commanding an artillery battery witnessed the events at Hill 60 and the Caterpillar: ‘At exactly 3.10am Armageddon began. The timing of all the batteries in the area was so wonderful, and so a second every gun roared in one awful salvo. At the same moment the two greatest mines in history were blown up – Hill 60 and one immediately to the south of it. I cleared everyone out of the dugouts and was watching for it. Never could I have imagined such a sight. First, there was a double shock that shook the earth here 15,000 yards away like a gigantic earthquake. I was nearly flung off my feet. Then an immense wall of fire that seemed to go half-way up to heaven. The whole country was lit with a red light like in a photographic dark-room. At the same moment all the guns spoke and the battle began on this part of the line. The noise surpasses even the Somme; it is terrific, magnificent, overwhelming. It makes one almost drunk with exhilaration, and one simply does not care that we are under all concentrated fire of all the Hun batteries.

Caterpillar Mine crater, Hill 60 today. Authors image

Specially built platforms were built on Kemmel Hill for the press and VIP’s to observe the mine explosions. It was also from here that Lieutenant Brian Frayling, 171 Tunnelling Company observed the explosions as an official observer for the Royal Engineer tunnelling companies. He had worked on the Spanbroekmolen mine and had hoped to have had the pleasure of detonating that mine. He was also concerned that the mines would not blow as they had been ready to blow for nearly twelve months and the ammonal may have been contaminated with dampness. . He wrote of the explosion at Spanbroekmolen from his vantage point: ‘It was a sheet of flame that tongued in the end. It went up as high as St Paul’s - I estimated about 800 feet. It was a white incandescent light darting high in the air. We had calculated the enemy here would go up as gas at over 3,000 degrees Centigrade.’ He visited the site of the mine afterwards and recorded: ‘It left a deep crater and the largest piece of the enemy I could locate there in daylight was a foot in a boot.

IWM Q2325 British soldiers stand looking into the huge mine crater at Messines Ridge, blown up on the morning of the battle. Photographed on 11 June 1917

According to Grieve and Newman in their book ‘Tunnellers’ the Ontario Farm mine resembled a seething caldron. ‘For a long time after the blow the crater resembled a seething cauldron, the semi-liquid mud bubbling like some gigantic porridge pot on the boil.

War correspondent Philip Gibbs reported: ‘The most diabolical splendour I have ever seen. Out of the dark ridges of Messines and Wytschaete and that ill-famed Hill 60, there gushed out and up enormous volumes of scarlet flame from the exploding mines and of earth and smoke all lighted by the flame spilling over into fountains of fierce colour, so that all the countryside was illuminated by red light. Where some of us stood watching, aghast and spellbound by this burning horror, the ground trembled and surged violently to and fro. Truly the earth quaked…

Maedelstede Farm mine crater today. Used for private fishing. Authors image.

The Aftermath

The tunnelling and mining operation at Messines were a staggering feat of engineering by the Tunnelling Companies with all nineteen mines, twenty-three had been made ready, detonated. By midday on 7 June the objectives had been achieved and the front line and the fighting had moved onto the main objective of the Oosttaverne Line. On the 8 June, Plumer met with the commanding officers of the Tunnelling Companies to congratulate them on their achievements.

After the war, Sir John Norton-Griffiths, Bart, in an after-dinner speech he gave in 1927, looked back on the Messines Ridge attack and reminded his audience of the tunnellers ‘stupendous importance’: ‘All we said had come true. There was not the slightest doubt that the frontal attack without the mines would have been absolute failure and would have cost… 50,000 men…This stupendous artificial earthquake shook the ridge from end to end…and enabled the army – as we had promised - to walk to the top of the ridge in comparative safety.

The main features of the Messines mines were the extremely large amount of explosives used, totalling some five hundred tons. The time lapse between placing the mines and firing them, mainly due to the cancellation of the 1916 offensive. The number of charges placed, twenty-three in all, with nineteen blown. The depth and length of the shafts and galleries; along a ten mile front. All of these features combined to make this the largest mining attack in the history of warfare

German Losses

The Messines attack was a comprehensive defeat for the Germans of that there is no doubt. However, German casualties have been exaggerated. The psychological effect on the defenders was enormous with many stupefied and shell shocked and moral was shattered and fear and abject terror took hold. German prisoners totalled 7,354. It is unlikely that the true number of dead and missing from the mine explosions will ever be known. In the book ‘Beneath Flanders Fields, the Tunnellers War 1914-18’ the author’s state: ‘Of a total of around 20,000 German casualties at the end of the first day, ten officers and 679 men were known to have died when the Hill 60 and Caterpillar mines went up, and a further 400 souls simply ceased to exist in the St Eloi blast. …Even an approximate final number for all the mines cannot be extrapolated from these two examples as the sectors in question were known to be heavily manned… by contrast, the trenches at which were obliterated by the five mines at Petit Bois and Hollandscheschuur were understood to have been lightly held, and farther south opposite Trench 121 the greatest fear of the British high command, a limited withdrawal, had been independently effected by order of the local commander.

In his memoirs Ludendorff wrote: ‘We should have succeeded in retaining the position but for the exceptionally powerful mines used by the British, which paved the way for their attack… The result of these successful mining operations was that the enemy broke through on June 7th… the moral effect of the explosions was simply staggering.

The Lost Mines

La Petite Douve Farm - In late summer 1916, the Germans discovered the mine at La Petite Douve Farm when they were probing forward, about 80 feet down, under a house and outbuilding when they struck timber. They removed some of the timber to reveal a gallery and a huge mine charged with 35 tons of ammonal in tins. They began to haul out the tins and exposed the firing wires. As the officer in charge went forward to cut them Lieutenant Peter King of 171 Tunnelling company pressed the exploder handle and blew a camouflet killing the officer and eight men.

La Petite Douve Farm today. Authors image.

Having finished the main mine in July 1916, the British had also begun an extension tunnel that was aimed at an adjacent German strong point. As soon as this work began German counter-mining was heard and it was clear that the Germans were about to enter the main tunnel. The British officers Lieutenant Peter King and Lieutenant Percy Ellis asked for permission to blow the mine. This was denied and instead they set a smaller 1,000lb charge in the extension tunnel to be blown as a last resort. It was this charge that King blew when he realised that the Germans were entering the main tunnel. On the 28 August the Germans blew their own camouflet estimated at 6,000lbs of ammonal and this wrecked the main tunnel, burying four men, and destroying the firing circuit to the main mine. It was then that British had the idea to divert the River Douve into the entrance chamber in the hope that this would also flow into the German workings, and this was done. The owners of La Petite Douve Farm, the Mahieu family, rebuilt it after the war and renamed it La Basse Cour. La Petite Douve mine—with its 50,000 lb (22,679 kg) charge—lies 70 feet beneath a barn, next to the farmhouse. Interviewed by a journalist from the British newspaper The Telegraph in 2004, M Mahieu, 60, living at the farm with his wife and daughter said: “It doesn’t stop me sleeping at night,”

Peckham Farm

‘A’ gallery under Peckham Farm was blown on 7 June. ‘C’ gallery with 20,000 lb (9,071 kg) of explosive stacked in several chambers was abandoned when the gallery collapsed after the electric pumps broke down. A farm was built over this abandoned mine after the war.

Peckham 'A' gallery crater. the farm behind is built on 'C' gallery abandoned mine.

The Four Mines at the Birdcage, Ploegsteert - The four mines, created by the 3rd Canadian Tunnelling Company, at the ‘Birdcage’ which was a series of trenches and strong points at Le Pelerin, Ploegsteert, were left dormant. The British GHQ had decided that German reserves would be closer to the craters and therefore would be in a position to fortify them before the British infantry could get forward. It was decided to keep them charged for possible use in later operations.

After the British attack, Lieutenant B C Hall, 3rd Canadian Tunnelling Company wrote about his inspection of the dormant mines: ‘I then had to go and inspect the other mines which weren’t blown and send a report down as to whether the leads were alright and so on. The leads were alright but the tunnels were hour-glassing (the shaft lining had been fractured and sand was filling the chambers) – all the timbers were broken.’ The British had intended excavating the mine charges and removing the fifty-five tonnes of ammonal explosive after the war but after the German advance of April 1918, the precise location of the charges was lost and they were eventually abandoned.

Australian War Memorial H15258

On the 17 July 1955, the Number 3 Birdcage mine exploded, some thirty eight years after the charge had been laid. A massive burst of energy from a lightning strike had struck one of the armoured firing leads and blew the charge. It left a huge crater, today filled in and there is a slight depression in the ground to mark the location. No one was harmed. It is a reminder that the detonators are still highly dangerous however, what was surprising was that the ammonal had survived as this was an explosive that was prone to degradation in damp conditions (the tunnels had flooded).

The location of the abandoned mines at Le Pelerin. The field to the left of the pole is the location of the 1955 mine explosion.

Today, five Messines mines containing 156,000 lb (70,760 kg) of explosives lie dormant beneath the old battlefield. In addition, the number of smaller abandoned mines and camouflets cannot be estimated. Opinion is divided on their safety.

Sources and Further Reading

  • Captain W Grant Grieve and Bernard Newman, Tunnellers

  • Alexander Barrie, War Underground, The Tunnellers of The Great War

  • Beneath Flanders Fields, the Tunnellers War 1914-1918, Peter Barton, Peter Doyle, and Johan Vandewalle,

  • Underground Warfare 1914-1918, Simon Jones

  • Directing The Tunnellers’ War, The Tunnelling Memoirs of Captain HR Dixon MC R.E., edited by Phillip Robinson and Nigel Cave

  • Disputed Earth, Peter Doyle

  • Clay-kickers of Flanders Fields: Canadian Tunnellers at Messines Ridge 1916-1917, Brian Pacas

  • Trench Warfare 1850-1950, Anthony Saunders

  • Pillars of Fire , the Battle of Messines Ridge June 1917, Ian Passingham

  • Messines Ridge, Peter Oldham

  • The War Diaries of the Master of Belhaven, 1914-1918, R. G Hamilton

  • Armageddon Road A VC’s Diary 1914 -1916’, Billy Congreve

  • The Burgoyne Diaries, the First Winter at Ypres with the Royal Irish Fusiliers, Gerald Achilles Burgoyne

  • National Archives – War Diaries of the Tunnelling Companies

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