"Here we are sapping and mining under Fritz’s trenches and he is doing the same under ours and we can hear him quite distinctly by aid of a microphone listener."     Sgt Frederick

Mining as a method of breaking the built defences of an enemy has an ancient heritage. The Egyptians were known to have undermined city walls and the Assyrians had specialised engineering troops in 850BC. Mining became a standard tactic in siege warfare and by the 17^th Century designers such a Vauban were including complex counter mining measures into their geometric fortifications.

However, as artillery increased in power, prolonged sieges became a less frequent feature of warfare. That is until the Russo-Japanese War (1904-1905) gave a precursor of what was to become a common and terrifying element of the First World War.

By the end of 1914, as the opposing forces reached stalemate, the ubiquitous trenches of the Western Front began to emerge. Conditions for viable military mining were born and the lethal work of digging beneath the enemy’s fixed field defences, laying mines and counter mines began.

Formation of Royal Engineer (RE) Tunnelling

German Pioneers blew the first mine of the War late in 1914. This new threat from below  caused increased uneasiness in the British Infantry in their nascent trenches. British mining began on a localised level only, with shafts being sunk from front line trenches by RE Field Companies and skilled infantry. However, it was very quickly apparent that a more organised approach was the only way of ensuring schemes of sustainable defensive mining to counter the German threat.

As with so much of the advancement in military technology during the War, the impetus and organisations of an expanded military mining capability came from the civilian world.

At the outbreak of the War a millionaire entrepreneur, MP and mining engineer, John Norton Griffiths, had offered his  expertise to the War Office but with expectations of a short campaign his offer was turned down. All changed in February 1915 when he was given authority to raise a Tunnelling Company from workers employed him for the extension of Manchester's sewage system.

Norton Griffiths had realised that the geology of Manchester was very similar to that of Flanders and that the technique known a 'Clay Kicking', used by miners in his UK works, could easily transfer to the Front line. With his inimitable energy it took only 36 hours for the first 18 Clay Kickers to transfer to military service and be tunnelling to the enemy.

From this small beginning tunnelling capabilities expanded, reaching their peak in 1916 when around 25,000 men were employed in the 'Underground War'. Their tunnels protected 30 of the 80 miles of British held front line and 1,500 mines were blown.

Silent War

The main purpose of the Tunnellers work was to protect the infantry in their trenches from the actions of German Pioneers. This subterranean theatre of War relied on accuracy, technical ability and nerve.

In the clay of Flanders, Tunnellers employed the peacetime technique of ‘clay kicking’. With his back braced the seated miner would use his legs to push an extremely sharp ‘grafting tool’ into the clay. Working from the bottom up the kicker would work 9 inches before fixing a set of timber, a bagger would bag up the spoil and a trammer loaded a tram taking the spoil the surface. The process was almost silent and very fast.

In the chalk valley of the Somme, Norton Griffiths, turned to coal mining techniques and a relaxed top age of enlistment enabled very experienced civilian miners to enter military service. Digging proceeded with pick and some mechanisation but many tunnel galleries and mine chambers still had to be completed by hand, cutting the chalk with bayonets to limit noise.

In this way extensive systems progressed along and across the front lines; spearheading an enormous logistical effort to supply timber, explosives and other equipment whilst ensuring that spoil and any other sign of mining remained unobserved.

Secrecy was paramount as both sides established underground listening posts to monitor enemy activity and progress. At first relatively rudimentary methods such as water in a glass and augers were used but by 1915 the introduction of geophones was enabling much more accuracy. Using these tunnelling could be heard in clay from 100m and in chalk from a 240m distance. Establishing quiet relied fundamentally on discipline and attention to detail. British miners wore plimsolls underground, Germans remained in their hobnailed boots; British trucks and trams ran on rails screwed into place, German rails were nailed and by 1916 all British mine trolleys had self-oiling bearings.

Added, therefore, to the not inconsiderable general hazards of mining was the constant threat of defensive action by the enemy. Each side strove to disrupt the advancing enemy. Camouflet mines would be used to blow and cave-in enemy galleries; a staggered detonation could be primed to hit the rescue party which would deploy after the first blow. There are also instances of incursion and attack with hand to hand fighting taking place in mine galleries themselves.

Offensive Operations

The Somme offensive saw the first use of mining in the opening stages of a major 'push'. Months in advance of the battle thousands of RE Tunnellers worked to preparing 19 mines. These targeted strategic positions on the German front line.

Minutes before the first assault the mines were blown. The largest, Lochnegar mine at La Boiselle, blew over 60,000lbs of ammonal explosive and sent debris nearly 4000ft into the air. It successfully destroyed 9 German dugouts, about 300 men. However, as with many of the mines, the British failed to capture the strategic position formed by the crater. German machine gunners quickly positioned themselves on this vantage point.

Tunnelling Companies were also tasked with digging Russian Saps. These shallow tunnels crossed no-mans land to within metres of the German frontline with machine gun or trench mortar positions at their head. They could have provided essential shelter for Infantry, or surprise attack positions for bombing (grenade) parties before the attack. Many, however, were built in such secrecy that the Infantry were unaware of their existence whilst others were used successfully for communications and reinforcements.

Without doubt the most successful mining operation of the War was that at the Messine Ridge Offensive on the Ypres Salient 1917. Here 6000 Sappers and attached Infantry prepared 19 mines, holding nearly 1 million lbs of explosives across a 10 mile front.  The effort was enormous, relying on successful dispersals of tons of spoil, accurate surveying of targeted German positions and the constant husbandry of many mines which had been laid and tamped over a year in advance.  Time and geology combined to allow an extensive system which, when blown destroyed an enormous area of ground and is thought to have instantly killed 10,000 Germans. The remaining defenders were profoundly disorientated and incapable of mounting any resistance to the British attack. Indeed the blast even concussed some British troops waiting to attack.

Messine really marked the end of large scale offensive mining operations and defensive tactics began to shift. Tunnelling Companies were increasingly used to construct enormous subterranean systems of accommodation, headquarters, dressing stations and subways. During the final British Offensive in 1918 their knowledge of explosives, attention to detail and safety saw them remove about 2.5 million pounds of explosives from German mines and booby traps.

"The fighting spirit and technical efficiency [of the Tunnellers] has advanced the reputation of the whole Corps of Royal Engineers."      Field Marshal Douglas Haig

For Gallantry

On the 4^th August 1916 Sapper William Hackett won the only Victoria Cross ever to be awarded to a military miner.

“For most conspicuous bravery when entombed with four others in a gallery owing to the explosion of an enemy mine. After working for 20 hours, a hole was made through fallen earth and broken timber, and the outside party was met. Sapper Hackett helped three of the men through the hole and could easily have followed, but refused to leave the fourth, who had been seriously injured, saying," I am a tunneller, I must look after the others first." Meantime, the hole was getting smaller, yet he still refused to leave his injured comrade. Finally, the gallery collapsed, and though the rescue party worked desperately for four days the attempt to reach the two men failed. Sapper Hackett well knowing the nature of sliding earth, the chances against him, deliberately gave his life for his comrade".   The London Gazette, dated 4 August 1916

William Hacket’s Victoria Cross can be seen from May 2017 at the Royal Engineer’s Museum, Chatham.