This month marks the centenary of the beginning of the Battle of the Somme in northern France, a WWI battle fought by the empires of Britain and France against the German Empire which lasted from July 1 – November 18, 1916. It is notable for being one of the large battles of the war which was supported by mine explosions.

I looked through the archives of Mining Magazine to see if I could find any reference to the battle itself, but there was no mention of it until 1919. However, there were many restrictions on war reporting in Britain at the time, especially any reports that might sap public morale or criticise the war effort.

While the Battle of the Somme is now remembered as one of the bloodiest battles of WWI, with over a million casualties in total over the nearly five months it lasted (there were 57,470 casualties in the British Army on the first day of the battle alone), that was not publicly reported at the time. According to The Guardian: “Even the bloodiest defeat in British history, at the Somme in 1916 - in which Allied troop casualties numbered 600,000 - went largely unreported. The battle’s disastrous first day was reported as a victory.”

As a result, it should be no surprise that Mining Magazine made no mention of it until several years later when the war had concluded. In the opening pages of the January 1919 issue, the editor Edward Walker praised the contribution of the miners during the war and recorded Field Marshal Douglas Haig’s words of thanks for their role:

Mining engineers have done much for their country during the war. Their work does not appeal to the man in the street in the same way as the exploits of the airmen, or the adventures of the Vindictive, but none the less it contributed in no small measure to the success of the campaigns.

It is gratifying to put on record Sir Douglas Haig’s letter of appreciation, wherein he thanks the engineers for their services and speaks of the high quality of their performance: “A large number of men are now being withdrawn from Tunnelling Companies for urgent work at home. Before they leave the country I wish to convey to the Controllers of Mines and to all ranks of Tunnelling Companies, both Imperial and Overseas, my very keen appreciation of the fine work that has been done by the Tunnelling Companies throughout the last four years.

“At their own special work, mine warfare, they have demonstrated their complete superiority over the Germans, and whether in the patient defensive mining, in the magnificent success at Messines, or in the preparation for the offensives of the Somme, Arras, and Ypres, they have shown the highest qualities both as military engineers and as fighting troops. Their work in the very dangerous task of removing enemy traps and delay-action charges, on subways, in dug-outs, bridging roads, and the variety of other services on which they have been engaged, has been on a level with their work in the mines.

“They have earned the thanks of the whole Army for their contribution in the defeat of the enemy. Their fighting spirit and technical efficiency has enhanced the reputation of the whole Corps of Royal Engineers and of the Engineers of the Overseas Forces. I should also like to include in the appreciation the work done by the Army Mine Schools and by the Australian Electrical and Mechanical Mining and Boring Company.”

The tunnelling companies were specialist units within the British Army that were formed specially to dig attacking tunnels under enemy lines. The German side was the first to employ this technique in WWI, exploding ten mines under British lines in December 1914.

The British Army created eight tunnelling companies in February 1915 as a response, which were operational in Flanders by the following month, increasing to 20 tunnelling companies by mid-1915. Notices requesting volunteer tunnellers were posted in collieries, mineral mines and quarries across Britain.

Geology

The underlying geology of the ground on the Western Front varied a lot, requiring different tunnelling methods in different areas. In the earlier stages of the war it was not fully appreciated that knowledge of geology was crucial for successful mining, and many early attempts at mining and tunnelling were uncoordinated and unsuccessful. However as qualified geologists were recruited, the mining became more effective.

Understanding of the geology was vital in determining whether it was possible to sink a shaft, how deep it was possible to mine and how quickly tunnels could be driven. Understanding of the hydrogeology was also essential as in some areas the difference between the water levels in the summer and the winter could be as much as 9m.

In May 1916, Major TW Edgeworth David arrived in France. A Welsh Australian geologist and Antarctic explorer who was Professor of Geology at the University of Sydney, he brought much-needed expertise to the mining efforts and was given the title 'Geological Adviser to the Controllers of Mines in the First, Second and Third Armies'. Under his leadership, thousands of boreholes were drilled along the front to determine the soil composition, and coloured maps were produced to indicate the type of soil and what type of mining activity might be suitable. He also advised on the construction of dug-outs and trenches, and on the siting of wells for the provision of clean drinking water. While the Flanders region consisted of soft waterlogged clays, the harder chalk formations of the Somme was much more suited to mining.

Tunnelling companies

By mid-1916 the British Army had approximately 25 British tunnelling companies with 25,000 trained tunnellers, most of whom were volunteers from British coal mining communities, along with three Canadian, three Australian and one from New Zealand. In most cases, the company commander was a regular officer from the Royal Engineers while the company officers were mining or colliery engineers, civil engineers or men with previous experience of mining or tunnelling.

In the 2003 book ‘Mud, Blood and Poppycock’, author Gordon Corrigan related that there were sometimes misunderstandings due to the fact that most of the soldiers in the tunnelling companies were recruited straight from civilian employment and were not familiar with army life: “On one occasion representatives of the men informed their company commander that they were concerned about the eroding of pay differentials and that they intended to down tools until the dispute was resolved. The company commander explained that this procedure might be all very well in the mines of Lancashire. The army, however, in its quaint way, would regard it as mutiny, which carried the death penalty. Work was instantly resumed.”

There were two types of mining carried out on each side of the conflict – defensive mining and offensive mining. Defensive mining was undertaken to destroy enemy tunnels before they had time to detonate their explosives. As practiced by the British Army, several shafts would be sunk to a depth of about 40ft (12.2m) and then connected up by a gallery. A number of tunnels would then be driven out from this gallery in the direction of the German lines, and at the end of each tunnel two or three men would crouch with the task of listening for sounds of enemy tunnelling. If such sounds were detected, a team would tunnel in that direction as quickly and silently as possible. The aim was to either blow the enemy tunnel up using a relatively small explosive charge that would be large enough to destroy it but not big enough to rupture the surface, or to break into their tunnel and kill the enemy miners in hand-to-hand combat.

Offensive mining consisted of tunnelling underneath enemy trenches and placing explosives at the end of the tunnel, which would be set off using electrical detonators, often in combination with an attack above ground.

Corrigan wrote that blowing increasingly larger mines under enemy positions had three main aims: “Firstly to collapse dug-outs and bunkers and kill the infantry in them; secondly to cause confusion and dislocation of command and control systems; and thirdly to blow a crater in enemy lines which, if seized by friendly infantry, could form a strongpoint within the enemy defences.”

However, he noted: “It has to be said that while the British were much better at producing the craters, the Germans were much better at seizing them.”

The tunnellers typically worked in a space around 2ft (61cm) wide and 4ft (1.2m) high, and with the risk of the tunnel either collapsing or being blown in by enemy fire. For example on June 22, 1916, five miners were buried alive at approximately 35ft (10.7m) below the surface by the explosion of the German Red Dragon mine, which blew in 25ft (7.6m) of their tunnel. A rescue party was formed to try to get them out, and after two days of digging an escape hole was driven through to the trapped men.

Three were helped to safety, but Private Thomas Collins of 14th Battalion, Welsh Regiment was seriously injured and unable to get out. The fifth miner, Sapper William Hackett, insisted on staying with Collins until they could both be rescued. Before the escape hole could be sufficiently enlarged, the gallery collapsed again, trapping the two men once more. The rescuers continued digging for three more days, but were forced to give up. William Hackett was awarded a posthumous Victoria Cross for his gallantry.

Despite the dangers, Corrigan noted: “When one recalls that most of these men had come from the coal mines or from tunnelling for the underground railway or the London sewers, when health and safety at work was not a priority and where accidents were common… Army tunnellers were better fed, and at least as well paid and housed, as their civilian counterparts; safety was a major consideration of their officers; and the risk of being blown up by the Germans was probably only marginally greater than the chance of roof collapse, flooding or gas explosion in their civilian occupations.”

The battle begins

Saturday July 1 was the opening day of the Somme offensive, with Allied troops set to attack the German lines between Serre and the River Ancre. Fewer mines than planned had been completed due to lack of manpower - however, nineteen mines had been excavated under German positions by the tunnelling companies, with eight large and eleven small charges to be detonated.

One of the largest of these, the Lochnagar mine south of the village of La Boisselle, had been dug under a German field fortification known as Schwabenhöhe, and consisted of a Y-shaped tunnel with two mines 60ft (18.3m) apart – it had taken three months to excavate, and between them the two mines contained 60,000lb (27.2t) of ammonal, an explosive made up of ammonium nitrate and aluminium powder. The other mines contained between 200-40,000lb (91kg – 18.1t) of ammonal.

The mines were set to be blown before zero hour, the start of the attack at 7:30am. The idea was that the explosions would disorientate the German defenders and kill many of them, allowing the British infantry to seize the craters before they could react and consequently obtaining strongpoints on the German front line.

Seventeen mines were detonated simultaneously by the British at 7:28am, two minutes before zero hour; the eighteenth failed and was set off late, while the nineteenth, the Hawthorn Ridge mine, was detonated early at 7:20am. The joint explosion of these mines ranks as one of the largest ever artificial non-nuclear explosions, and what was then the loudest human-made sound in history – the sound of the explosion was reportedly heard over 250km away in London.

Eyewitness accounts

The detonation of the Hawthorn Ridge mine was captured on film by Geoffrey Malins, a British film director who was the official British Army filmmaker. His camera was set up approximately 800m away, trained on the ridge and waiting for the explosion. He wrote: “The ground where I stood gave a mighty convulsion. It rocked and swayed. I gripped hold of my tripod to steady myself. Then for all the world like a gigantic sponge, the earth rose high in the air to the height of hundreds of feet. Higher and higher it rose, and with a horrible grinding roar the earth settles back upon itself, leaving in its place a mountain of smoke.”

The two charges of the Lochnagar mine created a vast, smooth sided, flat bottomed crater about 220ft (67m) in diameter excluding the lip and 450ft (140m) across. It is estimated that it destroyed nine German dug-outs and caused several hundred casualties.

The explosion of the Lochnagar and Y Sap mines was witnessed by 2nd Lieutenant Cecil Lewis of 3 Squadron, who was flying a Morane Parasol aeroplane over the battlefield to report back on British troop movements, observe German artillery so that it could be targeted, and watch for signal flares used by the infantry to request support. His aircraft was hit by lumps of mud thrown up by the blast.

He wrote: “At Boisselle the earth heaved and flashed, a tremendous and magnificent column rose up in the sky. There was an ear-splitting roar drowning all the guns, flinging the machine sideways in the repercussing air. The earth column rose higher and higher to almost 4,000ft [1,200m]. There it hung, or seemed to hang, for a moment in the air, like the silhouette of some great cypress tree, then fell away in a widening cone of dust and debris. A moment later came the second mine. Again the roar, the upflung machine, the strange gaunt silhouette invading the sky. Then the dust cleared and we saw the two white eyes of the craters. The barrage had lifted to the second-line trenches, the infantry were over the top, the attack had begun.”

The Kasino Point mine, which contained 5,000lb (2.3t) of ammonal, was set off late. The officer in charge hesitated when he saw that British infantry troops had left their trenches and begun to advance across no man's land. The troops were under bombardment from German machine guns so the officer detonated the mine anyway. It is possible that there was a defect in the charge, as instead of exploding upwards and falling around the crater, the debris from the mine spread outwards and fell over a large area.

Lance Corporal J Fisher with the 10th Essex Battalion was one of those out in no man’s land who witnessed the Kasino Point detonation, and later described it: “I looked left to see if my men were keeping a straight line. I saw a sight I shall never forget. A giant fountain, rising from our line of men, about 100 yards from me. Still on the move I stared at this, not realising what it was. It rose, a great column nearly as high as Nelson's Column, then slowly toppled over. Before I could think, I saw huge slabs of earth and chalk thudding down, some with flames attached, onto the troops as they advanced.”

This explosion caused casualties for at least four British battalions who were struck by falling stone and soil, and obliterated several German machine gun nests. It actually turned out to be one of the most tactically successful mine detonations of the battle however, as the late explosion took the Germans by surprise and allowed British troops to sweep over the German front trenches.

The detonations of the mines on the first day of the Battle of the Somme were exceeded the following year by those used in the Battle of Messines. In my next column, I will discuss the use of mining and tunnelling in the Flanders region of Belgium during WWI.